(*' . * < *! Digitized by the Internet Archive in 2018 with funding from Getty Research Institute https://archive.org/details/technicaldictionOOweal_O -asas* a s £ 8 ta %r^ u i& ta ‘ e i94tma,, amatm - p«- A TECHNICAL DICTIONARY OF TERMS USED IN ARCHITECTURE, BUILDING, AND ENGINEERING; MINING, SURVEYING, AND CONSTRUCTION; EARLY AND ECCLESIASTICAL ART; THE FINE ARTS, ETC. WITH EXPLANATORY OBSERVATIONS ON VARIOUS SUBJECTS CONNECTED WITH APPLIED ART AND SCIENCE. BY JOHN WEALE. iljirb dbitioit, toitlj (frormtions anb ^bbiiions. LONDON: VIRTUE AND CO., 26 , IVY LANE. NEW YORK: VIRTUE AND YORSTON. 1868 . ADVERTISEMENT TO THE THIRD EDITION. ! The Sale of Fifteen Thousand Copies of this “Technical Dictionary of Terms used in Architecture, Building, Engineering, Fine Art, and Kindred Studies,” is sufficient evidence, not only of a want supplied, hut also of the efficiency and practical utility of the work itself. In preparing this Thibd Edition for the press, some alterations and additions have been made to keep it up with the requirements of the day; and, in order not to add to its bulk, it has been deemed advisable to omit certain terms which were introduced into its predecessor, but which may there he looked upon as out of place. These terms, which occupied considerable space, were: Affections in General; Apostles of Christ; Ark of Noah,; Colours (Symbolic); Consideration; Farm; Five Species of Temples; God the Father , Son, and Holy Ghost; Millennium ; Mind of Man ; Talmud ; and some few others of like character; and the space so gained is now filled by additions to some of the definitions already given, or by the introduction of new technical terms. The late Mr. Weale’s preface to the former edition of this “Technical Dictionary” has been retained, because it contains the record of the origin of the series of rudimentary works on pure and applied science and arts with which his own name is associated, and gives the names of the men of science whose powerful aid contributed mainly to its great success. To that iv ADVERTISEMENT TO THE THIRD EDITION. list must now be added those of Charles Tomlinson, F.R.S., of King’s College, London; J. K. Heather, M.A., of the Royal Military College, Woolwich ; the late Sir William Snow Harris, F.R.S., of Plymouth; Robert Mallet, M.A., P.R.S. ; Robert Sabine, F.S.A.; Captain W. Knollys; John Keast Lord, F.G.S.; Dr. Robert James Mann ; Edward Hugent, C.E. ; Ralph Tate, F.G.S. ; the late Hr. S. P. Woodward, of the British Museum; Henry Bauerman, F.G.S. ; Thomas Hay S. Escott, B.A. ; and others, whose valuable contributions are included in the catalogue of the contents of this “ Rudimentary Cyclopaedia,” bound up at the end of this volume, in which will be found a classed arrangement of all the monographs already published as portions of it. This classification is intended to enable Mechanics’ Institutions and Free Libraries, both at home and in the colonies, to bind up the entire work in volumes, classed according to their several requirements. April, 1868. PREFACE. It was intended that the contents of this work should be comprised within the space of about one hundred and fifty i pages, and thus form a single volume of the series of * Rudi¬ mentary Treatises; 5 but in the course of its compilation it i soon became apparent that such confined limits were wholly j inadequate to the admission of explanations of terms which, j although not immediately connected with the subjects men- i tioned in the title-page, were yet deemed essential to their further amplification : its utility as a book of reference will therefore, it is hoped, be found commensurate with its neces¬ sarily increased extent. Since the publication, in 1819, of Mr. Peter Nicholson’s elaborate ‘Architectural Dictionary,’ in two quarto volumes, changes of vast import have occurred : the field of practical science has been widely extended, and proportionately occu¬ pied by a new generation of professional men and students; important advances have been made in the arts of design and construction ; and the extended application of steam as a motive power has not only produced an extraordinary de¬ velopment of the means of internal communication, but surmounted those impediments which considerations of space and time formerly presented to the pursuits of men in quest of business or pleasure,—thus influencing, to a great extent. PREFACE. vi the various operations by which the wants and luxuries of civilized life are supplied. In a ratio proportionate to the rapid extension of what may be strictly termed practical knowledge has the study of the more pleasurable sciences also progressed : archaeology, architecture, civil and mechanical engineering, geology, etc., have exercised a powerful and captivating influence, which has gradually led to the incorporation of societies or associations devoted to the cultivation and advancement of the several branches of human knowledge; and hence has arisen an extensive class of non-professional men, who, however duly acquainted with scientific principles, may yet be anxious to possess any easily available means of becoming familiar with the nomenclature and the technical language necessarily employed in a series of rudimentary treatises on the practical arts and sciences. Within the period already adverted to, much professional taste and skill have been displayed in the erection of public buildings, in the construction of engineering works of vast magnitude and importance (both at home and abroad), and in the invention of the improved machinery employed in the arts and manufactures of the country. These and similar causes have combined greatly to augment the ranks of a meritorious and useful class of men, among whom, more especially, new wants may be said to have been created,—a class which comprises no inconsiderable number of ingenious operative engineers, artisans, etc. ; and to such this work may become interesting and useful, however insufficient it may prove to those already advanced in their professional pursuits. Should, however, the paucity of information contained in the following pages induce others more competent to the task, and who have sufficient leisure for the purpose, to devote their talents and time to the production of a more PREFACE. vii comprehensive and more valuable compilation, some share of useful information will at least have been contributed to the means of supplying the wants of an improving age. The slender efforts here placed before the reader were ac¬ complished, by the aid of the lamp, after the hours usually devoted to the labours of business, and they are now, with the most humble pretensions, submitted to public approval. It has been well observed, that “the language of truth is simpleno attempt has here been made to trace the deriva¬ tions of the scientific or technical terms which have been adopted ; they are given and explained as generally written, spoken, and understood at the present period, and care has been taken to avoid surreptitious or unauthorized versions, with the view of correctly guiding the student and the operative workman in the onward path of knowledge. Some analogous explanations and references may probably appear, at a first glance, as superfluous, and to detract from the merits of the work; but when it is considered how numerous and varied, in the present age, are the ramifications into which the employment of those engaged in the building and constructive arts has been extended, and how earnestly the searchers after technical terms and meanings must desire the acquisition of a knowledge of what may not inaptly be designated as a correct disposition of fine art, any unfavour¬ able impression of this nature, hastily formed, will probably be removed upon mature reflection. In referring to the series of ‘ Rudimentary Scientific Works’ to which this ‘ Dictionary of Terms’ will, it is presumed, be deemed an appropriate Companion, it is proper to mention that the first suggestion as to their publication emanated from the late Major-General Sir William Reid, of the Corps of Royal Engineers, and myself. Sir William kindly contributed, as a commencement, Professor Fownes’s ‘ Rudimentary Che- PREFACE. mistry.’ This elementary treatise, the first of the series, and to which the recommendation of Sir William Reid was limited, had been printed originally at his own expense, for the lau¬ dable and special purpose of adding to the numerous educa¬ tional and scientific works which he had already distributed among different classes in the West India colonies. To Major-General Portlock, R.E., E. B. Denison, Esq., Q.C., and to Alan Stevenson, Esq.,of Edinburgh, James Peake, Esq., of Keyham (H.M.) Dockyard, Sir R. Macdonald Stephenson, Charles Wye Williams, Esq., of Liverpool, William Bland, Esq., of Hartlip, Kent, Hyde Clarke, Esq., David Gibbons, Esq., Joseph Gwilt, Esq., and to others who have so liberally con¬ tributed their aid in the production of the extensive treatises, I have to acknowledge my obligations. Of the First Edition 10,000 copies have been sold. The present Edition, the second, has been revised with care, and, it is hoped, will be found to be considerably improved. John Weale. 59, High Holborn, May, 1860. LIST OF THE WORKS WHICH HAVE BEEN CONSULTED IN THE COMPILATION OF THIS DICTIONARY. Adcock’s Rules and Data for the Steam Engine, etc. 12mo. 1839. Aide-Memoire to the Military Sciences. 3 vols. 8vo. Architectural Papers. 4 vols. 4to. Bartol’s American Marine Boilers. 8vo. 1851. Blashfield’s Terra Cotta Vases, etc. 4to. 1857. Britton’s Architectural Dictionary. 4to. 1838. Buchanan’s Technological Dictionary. 12mo. 1849. —— -Practical Essays on Mill-work and on Machinery and Tools. 2 vols. 8vo. Edited by George Rennie, 1841. Builder’s (The) Dictionary. 2 vols. 4to. 1788. Bury’s Styles of Architecture. 12mo. 1855. Calmet’s Dictionary of the Bible. 8vo. 1848. Campbell’s Text-Book of Inorganic Chemistry. 12mo. 1849. Castell’s Villas of the Ancients, fol. 1728. Clegg’s Essay on the Architecture of Machinery. 4to. 1842. -Manufacture and Distribution of Coal Gas. 4to. 1848. Dana’s Seaman’s Vade Mecum. 12mo. 1856. Dempsey’s Practical Railway Engineer. 4to. 1855. Dictionary of Painters, Sculptors, and Engravers. 8vo. 1810. Divers Works of Early Masters. 2 vols. imp. folio. 1847. Dobson’s Student’s Guide, by Garbett. 8vo. 1858-9. Dodd’s (Ralph) Observations on Water. 18mo. 1805. Ensamples of Railway Making. 8vo. 1843. Engineer and Contractor’s Pocket-Book for 1859. Engineering Papers. 6 vols. 4to. Ewbank’s Hydraulics and Machinery. 8vo. New York, 1849. Fairbairn on Cast and Wrought Iron for Building Purposes. 8vo. 1858. Fergusson’s Rock-Cut Temples of India : plates folio, text 8vo. 1845. Field’s Chromatography. 8vo. 1841. X LIST OF WORKS CONSULTED. Garbett (E. L.) on the Principles of Design in Architecture. 2 vols. 1852. Glossary of Architecture. 3 vols. Oxford, Parker. 1845. Greir’s Mechanical Dictionary. 12mo. 1850. Gregory’s Mathematics for Practical Men : large 8vo. 1848. Gwilt’s (Joseph) Encyclopaedia of Architecture. 8vo. 1857. -. edition of Sir William Chambers’s Civil Architecture. 2 vols. imperial 8vo. 1824. ---— Notitia Architectonica Italiana. 8vo. 1818. Hamilton on Terms used in the Arts and Sciences. 12mo. 1825. Hann’s Theoretical and Practical Mechanics. 8vo. 1849. I-Iann’s etc. Theory and Practice of Bridges. 4 vols. in 3 : large 8vo. 1858. HolzapfFel’s Turnery and Mechanical Manipulation. 3 vols. 8vo. 1848. Homersham on Water Supply to Manchester and the adjacent Towns. 8vo. 1849. Hunt’s Tudor Architecture. 4to. 1830. Hutton’s Mathematical and Philosophical Dictionary. 2 vols. 4to. 1815. Jamieson’s (Dr.) Dictionary of Mechanical Science. 4to. 1827. ■- - -Mechanics for Practical Men. 8vo. 1830. Leeds’s Rudimentary Treatise on the Orders of Architecture. 12mo. 1855. Meason’s Architecture of the Great Painters of Italy. 4to. 1828. Meteorological Society’s Transactions, vol. i. large 8vo. 1839. National Encyclopaedia, by Mr. Charles Knight. Nicholson’s Architectural Dictionary. 2 vols. 4to. 1819. ■—-- Mechanical Exercises. 8vo. 1819. Normand’s Parallel of the Orders of Architecture, by Pugin : folio. 1829. Palladio’s Architecture, with Notes by Inigo Jones. 2 vols. folio. 1742. Pambour’s Practical Treatise on Locomotive Engines. 8vo. 1840. Papers connected with the Duties of the Corps of Royal Engineers. 10 vols. 4 to. 1835-1849. Papers and Practical Illustrations of Public Works, both British and American, royal 8vo. Pole on the Cornish Pumping Engine. 1 vol. 4to. folio plates. 1844. Pryce’s Treatise on Mines and Minerals: folio. 1773. Pugin’s True Principles of Pointed or Christian Architecture. 4to. 1841. -Apology for the Revival of Christian Architecture in England. 4 to. 1843. Reid (Major-General Sir Wm.) on the Law of Storms: large 8vo. 1850. -Variable Winds : crown 8vo. 1857. Rennie’s (Sir John) Harbours, Docks, and Coast Engineering. 2 vols. imp. folio. 1855. Repton’s Theory and Practice of Landscape Architecture: large 4to. 1805. Rich’s Companion to the Greek Lexicon and Latin Dictionary. 8vo. 1849. Smeaton’s Reports. 4to. 1837. LIST or WORKS CONSULTED. xi Smith’s Classical Dictionary: large 8vo. 1849. Stephenson’s (Robert) Report on the Atmospheric Railway System. 4to. 1844. Stuart’s Antiquities of Athens. 4 vols. folio. Taubert’s Use of Field Artillery in Service, translated by Lieut. H. II. Maxwell. 1856. Templeton’s Workshop Companion, 1858. Thorman’s Taunus Railway. 4to. 1846. Tomlinson’s Rudimentary Natural Philosophy. 12mo. 1856. Transactions of the Institution of Civil Engineers. 3 vols. 4to. 1835-40. Tredgold on the Steam Engine. 2 vols. 4to. 1838-1849. -Strength of Cast Iron. 8vo. 1842. Tredgold’s Elementary Principles of Carpentry. 4to. 1856. Vitruvius’s Civil Architecture, by Wilkins: imperial 4to. 1812. Watson’s Account of Mines. 8vo. 1843. Wicksteed’s Experimental Inquiry into Cornish Engines. 4to. 1845. -Work on Cornish and Boulton and Watt Engines. 1846. Wightwick’s Hints to Young Architects. 8\o. 1846. Williams (Chas. Wye) on Combustion. 2 vols. 12mo. Willis’s (Professor) Architectural Nomenclature. 4to. Cambridge. —--System of Apparatus for the use of Lectures. 4to. 1841. And lastly, The Dictionary of Architecture, by the Architectural Publication Society, of which several Parts in folio have already appeared. To this really learned and valuable work I am indebted, and acknow r - ledge with much pleasure and thankfulness the several extracts made from it, and testify to its great utility to the profession at large. DICTIONARY OF TERMS USED IN ARCHITECTURE, BUILDING, ENGINEERING, NAVAL ARCHITECTURE, ARCHAEOLOGY, etc. AAR ABACUS. ABB Aaron’s-rod, an ornamental figure representing a rod with a serpent entwined about it; improperly called the caduceus of Mercury. Abacia, in antiquity, a kind of roll, resembling a bag. Abaciscus, small tesserae or square stones, for tessellated pavement. Abacot, the cap of state, a double crown formerly worn by the sove¬ reigns of England. Abaculus, a small table or desk. Abacus, a small tile or covering mem¬ ber of a capital, varying in the several orders: in Grecian Doric, square, without chamfer or mould¬ ing; in Roman Doric it has an ogee or fillet round the upper edges; in the Tuscan, a plain fillet and a ca- vetto under it; in Grecian Ionic it is thinner, with ovolo only; in Ro¬ man Ionic, an ogee and ovolo, and fillet above; in the Saxon and Nor¬ man styles, and in early English, it varies in form and substance,—flat, chamfered, and hollow, circular and octagonal, with mouldings, latterly decorated. Abacus (among mathematicians), a table strewed over with dust or sand, on which the ancients used to draw their schemes and figures. Abacus, a multiplication - table, in form of a right-angled triangle. Abacus (in old records), a counting- table used for calculations and schemes. Abacus major, a large trough to wash in. Abadir (Paul), born at Bordeaux in 1783, a pupil of Bonfin and Per- cier, built the church of St. Andre, and other public buildings in that city. Abaft, towards the stern of a ship. Abaiser, burnt ivory, or ivory-black Abamurus, a buttress or second wall, added to strengthen another. Abated, sunk or lowered. ‘ The Marbler’ “agrees that all the champes about the letters are to be abated and hatched curiously, to set out the letters.” Abatement, a carpenter’s term used by old authors, signifying the waste of a piece of stuff by forming it to a designed purpose. Abat-jour, a skylight, or aperture for the admission of light. Abattoir, a building appropriated to the slaughtering of cattle. Abat-vent, the sloping roof of a tower; a penthouse. Abat-voix, the sounding-board over a pulpit or rostrum. Abbey, a building annexed to or ad¬ jacent to a convent or monastery, for the residence of the abbot or abbess, and the whole combining a series of buildings for the accom- 1 ABERRATION. ABB modation of a fraternity under ecclesiastical government. Abbey gate-house, a lodge for warders or porters at the entrance of an abbey edifice. Abbot, the superior of a monastery of monks erected into an abbey or priory: there are various classes of abbots, as mitred, crosiered, car¬ dinal, regular, and commendatory abbots. Abbot's lodgings, in the early times of English ecclesiastical architecture, a complete house, with hall, chapel, and every convenience for the resi¬ dence of a spiritual baron. Abbreviate, to contract a word in writing or printing. Abbreviations , characters or marks over letters to signify either a word or syllable. Abel (John), an English architect of considerable notoriety, died in 1674, aged 97 : built, during the periods of James I. and Charles I., the market-houses of Brecon, Here¬ ford, Weobly, with its school- house, Kingston, and Leominster, and the timberwork of the church at Abbeydore; and being in Here¬ ford when the Scots besieged it in 1645, he constructed mills to grind corn, which were of great use to the besieged, and for which Charles I. afterwards made him one of his carpenters. Abele-tree, a species of white poplar. Aber, or Abber, the fall or emptying a lesser water into a greater, as of a brook into a river: hence several towns situated on or near the mouth of rivers generally derive the first parts of their names. Aberration, in astronomy, an appa¬ rent motion of the celestial bodies occasioned by the progressive mo¬ tion of light and the earth’s annual motion in its orbit. Aberration, in optics, the deviation or dispersion of the rays of light when reflected by a lens, by which they are prevented from meeting or uniting in the same point, called the geometrical focus ; but spread ABS over a small span, they produce a confusion of images. Ablactation, in gardening, the method of grafting. Ablaqueation, the opening of the ground around the roots of trees, for the admission of the air. Aboard, a nautical term, the inside of a ship, or to go on board. Abobe, unbaked bricks in Spain, used for the erection of cottages in Cas¬ tile and Leon. About-ship, the situation of a ship after she has tacked. About-sledge, the largest hammer em¬ ployed by smiths; it is slung round near the extremity of the handle, and generally used by under work¬ men, called hammer-men. Abrasion, the effect produced by at¬ trition or rubbing. Abraum, a red clay, used in England to give a red colour to new maho¬ gany. Abreast, as when two ships have their sides parallel. Abreuvoir, a watering-place. Abreuvoir, in masonry, the interstice or joint between two stones to be filled up with mortar or cement. Abscissa, a geometrical term for a segment cut off from the straight line by an ordinate to a curve. Absis, or Apsis, the bowed or arched roof of an oven, room, or house. Absis, or Apsis, the ring or compass of a wheel. Absorbents, in chemistry, those earthy substances capable of uniting, by capillary attraction, a large pro¬ portion of water: such are mag¬ nesia, lime, and clay, when dry and porous. Absorbing-well, a shaft or boring for removing either the excess of drain- age-waters, or the foul waters pro¬ duced by manufacturing purposes. Absorption is the successive and inti¬ mate penetration of a gas, or a liquid, into any substance; but fa¬ miliarly, the taking up moisture, in any material, by capillary at¬ traction. Absthdnes, a lower kind of nobility 1 ABS ABUSES. ABU formerly in Scotland, but now ex¬ tinct. Abstract (To), a term used by arti¬ ficers and surveyors in arranging and apportioning theii work, to explain and price it. Abstract mathematics, otherwise de¬ nominated pure mathematics, that branch of the science which treats of simple properties, magnitude, figure, or quantity, absolutely and generally considered. Abstraction and absorption of heat is that process under which caloric, or heat, passes from any body to whatever surrounds it, or to any conducting substance with which it is in contact. Absurd, a term used in demonstrating converse propositions. Abundant number, a number whose aliquot parts, added together, make a sum which is greater than the number itself. Abuses: “Architecture,” says Palladio, “ being an imitatrix of Nature, de¬ lights in that which is most conso¬ nant with her prototype.” Ancient edifices were built with wood, trees forming the columns; and when architects began to build with stone, they made the columns to imitate the trunks of trees, taper¬ ing from their bases. Being thus originally of wood, and therefore liable to split when much loaded, they bound them with rings at top and bottom. Thus the bases and capitals in the different orders seem originally derived from these bandages, though they are now become essential ornaments. Thus also in entablatures, the triglyphs, modillions, and dentils represent the ends of those beams and tim¬ bers which are employed for the support of the floors and roofs. If therefore all these conditions be duly considered, those practices in building are highly to be repro¬ bated which are in opposition to that analogy which should exist between the original and its imi¬ tation, or which depart from Na- b 2 ture and the simplicity observable in all her works. Consoles or cartouches, which are of a scroll-like form, should never be employed for the appa¬ rent support of great weights, in place of columns or pilasters; nor should they ever project from, or spring out of cornices. Pediments and frontispieces over doors and windows, or elsewhere, should on no account be broken or disconnected in the middle; for the intention of these is to shelter the parts below from the rain, and this result is completely obviated by such a practice. The projecture of cornices, though for the purpose of shelter¬ ing buildings,, should not be more than in due proportion to their height,whether or not accompanied by columns; for if too heavy, they seem to threaten with danger those who are under them; and if too small in projection, they do not properly perform their office. Again, those columns which are feigned to be composed of several pieces, by being jointed together with rings, should be carefully avoided, because the more solid and strong the columns appear, the better they seem to answer the pur¬ pose for which they were erected, which is securely to receive the superincumbent loading. There are many other abuses which the authority of great mas¬ ters may sanction, but not justify; and such will readily occur to the student, and themselves point out that they ought to be avoided. Abutment, the solid part of a pier from which the arch springs. Abutments, the extremities of a bridge, by which it joins upon the banks or sides of a river, etc.; in carpentry and joinery, the junc¬ tions or meetings of two pieces of timber, of which the fibres of the one run perpendicular to the joint, and those of the other parallel to it. 3 ABU ACCESSES. ACE Abuttals, the buttings or boundaries of land. Acacio, a heavy, durable wood, of the red mahogany character, but darker and plainer : it is highly esteemed in ship-building. Academia, in antiquity, a villa or plea¬ sure-house in one of the suburbs of Athens, where Plato and other philosophers assembled. Academician, a member of a society or academy instituted for the cul¬ tivation of the arts and sciences. Academy-figure is a drawing or de¬ sign, done after a model, with crayon or pencil. Acanthus, the plant Branca ursina, in English bear's-breech, the leaves of which are imitated in decorating the Corinthian and Composite ca¬ pitals of columns. Accelerated motion, a force acting in¬ cessantly upon a body; called also a constant or uniformly accelerating force when the velocity increases equally in equal times : the force of gravity near the earth’s surface is of this kind; it generates a velo¬ city of 32£ feet in each second of time; that is, a body, after falling one second, acquires_a velocity of 32i feet; after falling two seconds, it will acquire a velocity of 2 x 32£ feet; after three seconds, a velocity of 3 x 32£ feet, and so on. Accelerating force, in physics, the force which accelerates the motion or velocity of bodies; it is equal to, or expressed by, the quotient arising from the motion or absolute force, divided by the mass or the weight of the body moved. Accelerative or retardative force, is commonly understood to be that which affects the velocity only, or that by which the velocity is ac¬ celerated or retarded; it is equal or proportional to the motive force directly, and to the mass or body moved inversely. Accesses, approaches or passages of communication between the va¬ rious apartments of a building, as I corridors. Accessible, in surveying, a place which admits of having a distance or length of ground measured from it; or such a height or depth as can be measured by the application of a proper instrument. Accessories, or accompaniments, in painting, secondary objects to the principal one in a picture, intro¬ duced as explanatory and illus¬ trative of the scene: sometimes they are considered as solely con¬ tributing to the general effect and harmony of the piece. Accidental point, in perspective, the point in which a right line drawn from the eye, parallel to another right line, cuts the picture or per spective plane. Acclivity, the slope or steepness of a line or plane inclined to the hori¬ zon, taken upwards; in contra¬ distinction to declivity, which is taken downwards. Accouplement, in carpentry, a tie or brace, or the entire work when framed. Accretion, in physics, the growth or increase of an organized body. Accubitus, a room annexed to large churches, in which the clergy oc¬ casionally reposed. Aceric acid, in chemistry, an acid formed from the juice of the maple- tree. Acerra, in antiquity, an altar erected, among the Romans, near the bed of a person deceased, on which his friends daily offered incense until his burial. Aces (a sea term), hooks for the chains. Acestides, the chimneys of furnaces where brass was made; they were contrived to be narrow at top, on purpose to receive and collect the fumes of the melting metal, in or¬ der that cadmia might be produced in greater quantities. Acetate of lead,—sugar of lead,—a compound of acetic acid aud lead. Acetate of potash, a compound of acetic acid and potash, produced 4 ACH ACR0TER1A. ACT by dissolving carbonate of potash in distilled vinegar. Achievement, the ensigns armorial of a family. Achleitner (Simon) was master of the works at St. Stephen’s, in Vienna, 1481. Achromatic, a term expressing ab¬ sence of colour; in optics, applied to telescopes invented to remedy aberrations and colours. Achromatic, without colour, is ap¬ plied in decorations to total absence of colour: mere white and black, or white and gold, may be consi¬ dered in this sense achromatic. Acids, in chemistry, are sour to the taste, and convert vegetable blues to a red colour; they combine with alkalies, earths, and metallic oxides, and form, with them, the well- known compounds named salts. Acinose, a term applied to iron ore found in masses, and of several colours. Acisculis, a small pick used by ma¬ sons, having one end like that of a hammer and the other pointed. A-cock-bill, in navigation, the situ¬ ation of the yards when they are topped up at an angle with the deck; the situation of an anchor when it hangs to the cat-head by the ring only. Acolyte, in the ancient church, a person who trimmed the lamps, prepared for the sacrament, etc. Acorn, the seed of oak: imitations of it are much used in architec¬ ture, and it is sometimes intro¬ duced instead of the egg in the Roman ovolo. Acoumeter, an instrument invented by Itard for estimating the extent of the sense of hearing. Acoustics, the doctrine or theory of sounds, consisting of diacoustics, or direct sounds, and catacoustics, or reflecting sounds. Acre, a measure of land, containing, by the ordinance for measuring land in the time of Edward I., 160 perches or square poles of land ; and as the statute length of a pole is 5J yards, or 16| feet, the acre contains 4840 square yards, or 43,560 square feet. The chain with which land is now commonly measured, invented by Gunter, is 4 poles, or 22 yards, in length; and the acre is therefore just 10 square chains; and as a mile contains 1760 yards, or 80 chains, in length, the square mile is equal to 640 acres. The acre, in surveying, is divided into 4 roods, and the rood into 4 perches. Acrolithes, in sculpture, statues, the extremities of which are formed of stone. Acropolis, a building strictly appli¬ cable to a Greek city, and usually erected upon a hill, rock, or some natural elevation, and devoted to a magnificent temple ; also a tower, castle, or citadel. Acrostolion, in ancient naval archi¬ tecture, an ornament of the prow or forecastle of a ship, chiefly of war, most frequently circular or spiral. Acroteria, small pedestals at the angles and vertex of a pediment: the gate of the Agora at Athens is the only instance in which they appear in Grecian buildings. Actinometer: Sir John Herschel, at the third meeting of the British Association, submitted an instru¬ ment for measuring at any instant the direct heating power of the solar ray : it affords a dynamical measure of the solar radiation, by receiving a quantity of heat per second, or any short space of time, on a surface exposed to the sun. In making observations with this instrument, it should be freely ex¬ posed in the shade for one minute, and the variation read ; afterwards expose it for the same time to the solar action, and again note it; and lastly, repeat the experiment in the shade : the mean of the two varia¬ tions in the shade being subducted from the variation in the sun, the excess gives the dilatation per mi¬ nute due to the sun’s rays the 5 ADMEASUREMENT. AiDE ACT quantity subducted being the effect of the other causes at the time. Action, in painting or sculpture, the posture, attitude, expressive of the passion the painter or carver would convey to the mind of a spectator. Actus, a Roman measure of length, equal to 120 Roman feet. Acute angle, in geometry, less than a right angle, and measured by less than 90° or a quadrant of a circle. Acute-angled cone, that in which the opposite sides make an acute at the vertex, or whose axis, in a right cone, makes less than half a right angle with the side. Acute-angled section of a cone, an el¬ lipsis made by a plane cutting both sides of an acute-angled cone. Acute-angled triangle, that in which the three angles are all acute. Adam (Win.), an architect of Scot¬ land, died about 1760, designed and built several edifices. Adam (John), of Edinburgh, son of the above, executed several designs in Scotland. Adam (Robert), second son of Wil¬ liam : he and his brother James executed very many very splendid buildings in England and Scotland, more particularly in London, the Adelphi, Portland-place, Lans- downe-house, and other noble¬ men’s houses. Mr. Weale purchased several unpublished (and posthumous) plates at the sale of the effects in Albemarle-street in 1822, which he published as a third or supple¬ mentary volume to the two vo¬ lumes sometime previously pub¬ lished. Adam (James), architect, also a son of William Adam, died in Albe¬ marle-street in 1794, was with his brother Robert the intimate friend of Clerisseau, Zucchi, and patrons of other celebrated French and Ita¬ lian artists. Adam (William), architect, another son of the same William, built several houses in Whitehall, died in 1822, aged 84. Adamant, a very hard stone, used by the ancients for cutting and polish¬ ing other hard stones and glass. Adeling, a title of honour given to the children of princes among the Anglo-Saxons. Adhesion, the force with which differ¬ ent bodies remain attached to each other when brought into contact. Adit, the passage or approach to a house; applied also to the hori¬ zontal shaft of a mine, driven for the purposes of ventilating, water¬ ing, or draining. Adit-level, in mining, a horizontal excavation through which the wa¬ ter is drawn by the engine. Adjacent angle, in geometry, an angle immediately contiguous to another, so that one side is common to both. Adjutage (Ajutage), or jet-d'eau, a tube fitted to the aperture of a ves¬ sel through which water is to be played. Admeasurement, the measuring or finding the dimensions and quan¬ tity of a thing by the application of a standard or rule. Admeasurement, a process in the art of mensuration for measuring and determining dimensions of work. Adonia, a festival celebrated in ho¬ nour of Aphrodite and Adonis in most of the Grecian cities. Adrift, the condition of a vessel broken from her moorings. Adytum, the most sacred place in the heathen temples; the Holy of Ho¬ lies ; in Christian architecture, the chancel or altar-end of a church. Adze, an edged tool used to chip sur¬ faces in a horizontal direction; the axe being employed to chop mate¬ rials in vertical positions. /.Ebrechts (H.) was with Louis Ger- brandt and Klas Huygens, in 1499, to build the town-hall at Gonda, in Holland. AZcclesiolo, in Domesday Book, a chapel subordinate to the mother church. AEdes, an inferior kind of temple; in Christian architecture, a chapel; also sometimes applied to a house. 6 iEGINA MARBLES. JERA ^EDI JEdicula, a small chapel, house, or building of any kind ; not unfre- quently applied to the niches of tabernacles in a wall which held statues of the lares or penates. JEgina marbles: C.R.Cockerell,Esq., visited Athens with Mr. Foster in 1811. In examining the temples of Athens with their lamented friend and companion, the Baron Haller, some details, of singular interest and novelty, induced them to form the project of excavating the Temple of Jupiter at AEgina, for the purpose of ascertaining how far these might be found common to other remains of Grecian archi¬ tecture, as well as for the general object of advancing their stu¬ dies. The JEginetan statues furnish the only illustrations of the heroic costume and armour, as described by Homer, ACschylus, and the ear¬ liest Grecian writers; and the great nicety of execution in the smallest details corresponds perfectly with the exactness which the poets have observed in their description; a minute and scrupulous attention is paid to each tie and fastening ; and as if the whole had been of¬ fered to the severest scrutiny, the parts never seen were equally fur¬ nished with exact resemblance of each particular detail in the most ancient coins of Corinth, Sybaris, Posidonia, and the earliest Greek cities of Italy, as well as of Ionia, which were much earlier proficients in arts than those of Greece Pro¬ per ; and in the vases of the most archaic style (commonly in black on a red ground) we trace the cha¬ racter which is developed and ex¬ plained in these statues. In the magnificent statue of Mi¬ nerva, who, by her action, seems from Olympus to have just alighted to animate the combat by her pre¬ sence, we have the most antique costume hitherto known to us. The form of the JEgis is singular, nor have we seen it before in sculpture, surrounded with the tassels, the noise of which was said to have dismayed her oppo¬ nents : we know such a sort of appendage Jo have been in much earlier use than the more usual one of the serpents. These were undoubtedly of brass, or some me¬ tal which has (disappeared ; they were fastened by rivets of lead, most of which still remained. The holes by which the Gorgon’s head was attached to her breast were evident, and the whole of the ASgis was painted with scales in encaustic ; they could not however be discovered. The lion’s head attached to the extreme tile of this temple was found perfect, and in the blocking, which carries the Chimmra, was a sinking, corresponding with the thickness of the plinth, to which the legs were attached. The whole of the ornaments in¬ dicated on the several members of the cornice were painted on the marble in encaustic; as are the extreme tiles, forming the upper moulding of the pediment; and on the stone of which the whole tem¬ ple was constructed, is a thin coat or varnish of very fine and hard plaster. JEgricanes, a name given to rams’ heads when sculptured on friezes, altars, etc. 2Egypti.Ha, a species of Egyptian or¬ nament. yEmasia, a fence, or fence-wall. yEolipile, in hydraulics,an instrument consisting of a hollow metallic ball with a slender neck or pipe pro¬ ceeding from it, which being filled with water, produces a violent blast of wind. 2Eolus, a small portable machine for refreshing and changing the air of apartments. 2Eolus (in mythology, the god of ■winds), the name of a ventilator, or a machine used to extract foul air out of rooms. yErarium, a treasury among the Ro- 7 AESTHETICS. AER mans ; the place where public mo¬ ney was deposited. Aerial perspective, the relative appa¬ rent recession of objects from the foreground, owing to the quantity of air interposed between them and the spectator. Adro, according to Vitruvius, a bas¬ ket to carry earth in, used by the Romans. Aero-dynamics, the science relating to the active powers or forces of gaseous fluids. Aerology, the doctrine or science of the air. Aerometer, an instrument contrived to ascertain the mean bulk of gases. Aerometry, the science of measuring the air, its powers and properties. Aeronautics, the art of sailing or floating in the air. Aerostatics, the doctrine of the weight, pressure, and balance of the air and atmosphere. Adrugo, rust, more especially that of copper,—verdigris. Aesthetics, the power of perception by means of the senses: theword im¬ plies the perception and the study of those qualities which constitute the beautiful and artistic, and form the finer essence of all productions of fine art; it carries with it, there¬ fore, a more exact and philosophic meaning than the word ‘ taste in its adjective form, in which it more frequently occurs, it is particularly useful, as no adequate epithet can be substituted for it. Thus we speak of the ‘ aesthetic sense,’ of ‘ aesthetic feeling,’ or ‘study,’ or‘principles,’ etc. ; but we cannot correctly say, the ‘ tasteful sense,’ or ‘ tasteful study.’ Adstuarium, a description of the an¬ cient baths, to the flue from hypo- caustum or stove to chambers. AEsyinnium, a building in Megora ; so called from AEsymnius, its founder, who erected that edifice, ■which consisted of a counGil-hall round the tomb of his countrymen AGN who died in battle against the Persians. Adthousa, the portico on the sunny side of the court of a Greek dwell¬ ing. Aetoma, a pediment, or the tympanum of a pediment. Affection, in painting, the represen¬ tation of any passions, whereby they appear to be animated, and swell to the sight. Affinity, in chemistry, the power by which the ultimate particles of matter are made to unite, and kept united. Light has considerable influence in controlling chemical affinity. Hydrogen and chlorine gases mixed and exposed to the sun’s rays combine with explo¬ sion, and form hydrochloric acid. Chlorine and carbonic oxide gases exert no action on each other until they are exposed to the light, when they combine and form phos¬ gene gas. The Daguerreotype and Photography are beautiful illus¬ trations of the actions of light upon chemical substances. Afflux, a flow of electric matter to a globe and conductor, in opposition to efflux, from them. After, in ship-building, implies a connection, as belonging to the after-body, after-timber, etc. Agalma, a sculptural ornament or image. Ayer, a Roman acre of land. Agger, a heap or mound of any kind, formed of stone, wood, or earth. Agglutination , the cohesion of bodies. Aggregation, in chemistry, the col¬ lection of bodies, solid, fluid, or gaseous. Agiasterium, the sanctuary, which is the basilicae of the Latin Church. Agnolo (B. D’), born in 1459, ex¬ celled in inlaid works, and exe¬ cuted in Florence, besides some coffers in walnut-wood, a large figure-frame, described by Vasari : he was also the most celebrated carver of his time. 8 AGN AIR-PUMP. AIR Agnolo (D. D’), a son of the pre¬ ceding, Baccio : was also a wood- carver as well as an architect. Agnolo (G. D’) another son of Baccio: besides wood-carving, he gave more attention to architecture. Agora , a place of public assembly, in a Greek city, for the transaction of all public business; a market¬ place. Agrafe, a French term used by buil¬ ders for small cramps employed in fixing chimney-pieces, etc. Agrippa (Camillus), a distinguished Milanese architect of the sixteenth century. Aguilla, an obelisk, or the spire of a church-tower. A-hull, the condition of a vessel when she has all her sails furled, and her helm lashed a-lee. Aile, the wing, the inward portico, on each side of a church or other large building, supported by pil¬ lars within. Air-brick, an iron box used in walls, and usually made to the size of a brick, but with one of its faces formed into a grating. Air-casing, the sheet-iron casing which surrounds the base of the chimney of a steam-vessel, to pre¬ vent too great a transmission of heat to the deck. Air-drains, cavities between the ex¬ ternal walls of a building, protected by a wall towards the earth, which is thus prevented from causing dampness. Air-escape, a contrivance for letting off the air from water-pipes. Air-holes, those made for admitting air to ventilate apartments. Air-machine, in mining, the apparatus used for forcing purer air into or withdrawing foul air from parts badly ventilated. Air-pipes, in mining, tubes or pipes of iron or wood, for ventilating under ground, or for the convey¬ ance of fresh air into levels having j but one communication with the atmosphere, and no current of air: also used for clearing foul air from the holds of ships or other close places. Air-pump, a pneumatic instrument, by means of which the air is ex¬ hausted out of the proper vessels : its effects are produced by the elas¬ ticity of the air; and as at each stroke of the pump only a part of the remaining air is withdrawn, an absolute vacuum cannot be ob- j tained, although so near an ap- j proximation to it may be bad as j to remove the general effects of j the atmosphere. In steam-engines, i the proportion of the air-pump, as given by Watt, is usually about | two-thirds of the diameter of the j cylinder, when the length of the stroke of the air-bucket is half the j length of the stroke of the steam- i piston. The area of the passages j between the condenser and the air-pump should never be less than one-fourth of the area of the air- pump. The apertures through the air-bucket should have the same proportion ; and, if convenient, the discharging flap or valve should be made larger. The capacity of the condenser should at least be equal to that of the air-pump ; but, when convenience will admit of it, the j larger it is the better. Air-pump bucket, an open piston, i with valves on the upper surface, J opening upwards, so as to admit the air and water in the down- stroke, and lift it with the up¬ stroke of the pump. Air-pump rod, the rod for connecting the bucket to the beam. Air-shaft, in mining, a passage made for the air by digging. Air-tint, in painting, the tint by which the distant parts of a land¬ scape are rendered more distinct, or sometimes giving a misty appear¬ ance to the whole : it is generally compounded of a blue-grey, occa¬ sionally approaching to purple. Air-trap, a trap immersed in water, to prevent foul air arising from sewers or drains. Air-valve, applied to steam boilers B 3 9 AIR AIR-VESSEL. ALG for the purpose of preventing the formation of a vacuum when the steam is condensing in the boiler. Air-vessel, the closed cylinder con¬ nected to the discharge-pipe of a force-pump, and by the action of which the water ejected by the pis¬ ton or plunger of the pump enters the cylinder and compresses the air within; it acts as a spring during the return stroke, and thus renders the stream constant; also a cham¬ ber containing air, attached to pumps and other water-engines, for the purpose of making the dis¬ charge constant when the supply is intermittent. Aisle, the side-passage or division of a church, partially separated from the nave and choir by columns or piers. Aitre, a hearth or chimney. Ajambe, the French term for a win¬ dow : it differs from the usual French window in having four or more casements, with separate hinges and fastenings complete, instead of two upright ones, which they generally have. Alabaster, a species of gypsum, a mi¬ neral substance, chemically termed sulphate of lime; also a box or vase for holding perfumes and oint¬ ments, so called because originally made of alabaster, and for which the variety called onyx-alabaster was usually employed. Alba, a beacon or lighthouse. Albarium, white-wash ; according to Pliny and Vitruvius, a white stucco or plaster, made of a pure kind of lime burned from marble, and used to spread over the roofs of houses. Albarium opus, according to Vitru¬ vius, a species of stuccowork. Alberti (Leone Battista), the son of a noble Florentine, born at Genoa in 1406: an architect of some ce¬ lebrity, and an author on the sub¬ jects of architecture and paint¬ ing. Albertolli (G.), the son of an archi¬ tect, born at Bedana in 1742 : was an architect of repute, and pub- blished some works on ornament of refined taste. Alcha, a cellar, pantry, or an apart¬ ment for the reception of drinking vessels. Alchemist, one skilled in the art of alchemy or chemistry. Alchemy, that branch of chemistry which presumes the transmutation of metals: Lord Bacon calls it the art of distilling or drawing quint¬ essences out of metals by fire. Alcohol, in chemistry, a pure spirit. Alcoholometer, an instrument for as¬ certaining the strength of spirits. Alcorans, in oriental architecture, high slender towers attached to mosques, in which the Koran is read. Alcove, a recess in a chamber, or a , recess separated from other parts of the room by columns, antae, and balusters. Alder, a wood formerly much used. The common alder seldom exceeds 40 feet in height, is very durable under water, and was used for the piles of the Rialto at Venice, the buildings at Ravenna, etc.: it was formerly much used for pipes, pumps, and sluices. Aldrich (Henry), dean of Christ Church, Oxford, born in 1647 : he was distinguished for his architec¬ tural attainments, and published a work on its elements. Aleaceria, a palace, castle, or other large edifice. Aleatorium, an apartment in a Roman house appropriated to the use of persons playing with dice. A-lee, a term used to denote the posi¬ tion of the helm when it is put in the opposite direction from that in which the wind blows. Alembic, in chemistry, a vessel used in distillation. Aleois, loopholes in the walls of a cas¬ tle or fortification, through which arrows may be discharged. Algebra, literal arithmetic, or the science by which quantity, and the operations of quantity, are ex¬ pressed by conventional symbols. 10 ALTAR. aLH Alhambra, in Saracenic architecture, the royal palace of the kings of Granada. Alien priories, cells or small religious houses erected in different coun¬ tries, and distinguished as alien from their dependence on large foreign monasteries. Alipterion, in ancient Rome, a room wherein bathers anointed them¬ selves. Aliquot part, such part of a number as will exactly divide it without a remainder; a part as, being taken or repeated a certain number of times, exactly makes up or is equal to the whole: thus 1 is an aliquot part of 6, or any other whole num¬ ber. Alkalimeter, an instrument for mea¬ suring and determining the quan¬ tity and strength of alkalies. Allette, used to express a small wing of a building; also applied to a pilaster or buttress. Alley, a passage from one part of a building to another; a passage or court with houses. Alligation, one of the rules of arith¬ metic, by which are resolved ques¬ tions which relate to the com¬ pounding or mixing together of divers simples or ingredients. Allorium, a piazza, corridor, or co¬ vered way in the flank of a building. Alloy, baser metal, commonly mixed with the precious metals. Alluminate (To), in painting, to wash prints with alum-water, to keep the colours from sinking or run¬ ning. Alluminate (To), to enlighten; to give grace, light, and ornament. Alluvium, the debris occasioned by causes still in operation, as deposits left by the action of rivers, floods, and torrents. Almacantar, lines parallel to the ho¬ rizon, and conceived to passthrough every degree of the meridian. Almasia, in old records, the archives of a church ; a library. Almehrab, a niche in the mosques of the Arabs, for praying. ALT Almond-furnace, a furnace used by refiners, and called a sweep, for separating all sorts of metals from cinders, etc. Almond-tree, a hard, heavy, oily, or resinous kind of wood, somewhat pliable. Almonry, a room or place where alms were formerly distributed to the poor. Almshouse, a house for the reception and support of the poor. Aloof, in navigation, to keep the ship near the wind when sailing upon a quarter wind. Alquifore, lead ore found in Cornwall, and used by potters to green-var¬ nish their wares. Alrunce, small images carved out of roots of trees, and anciently held in much veneration by the northern nations. Altar, an elevated table of either stone, marble, or wood, dedicated to the ceremonies of religious wor¬ ship. “ And Noah builded an altar unto the Lord; and took of every clean beast, and of every clean fowl, and offered burnt-offerings on the altar.” Altar-piece, the ornamental sculpture or painting behind the altar in a Christian church. Altar-screen, the back of an altar, or the partition by which the choir is separated from the presbytery and lady-chapel. Altars, among the Greeks, according to Wilkins’s ‘ Vitruvius,’ faced the east, and were placed lower than the statues arrangedabout the cella, in order that those who offered up prayers and sacrifices might know, from their different heights, to what particular deities the several altars were consecrated. Altare chori, a reading-desk in a church. Altare farum, the lustre, chandelier, or cresset, suspended over an al¬ tar. Altimetry, the art of taking or mea¬ suring altitudes or heights. Altitude, of a figure, the length of a 11 ALT ALUMINIUM. AMP line drawn perpendicularly from the vertex to the base. Altitude of the eye in perspective, a right line let fall perpendicular to the geometrical plane. Altitude of a figure in geometry, the nearest distance between the vor¬ tex or a top of that figure and its base. Altitude, height. Alto-rilievo, highly relieved sculpture representing figures either entirely or nearly detached from the back¬ ground. Alum, a salt extracted from various minerals called alum ores : of great use to chemists, dyers, and artists; acid and sharp to the taste. Aluminium is a metal which by unit¬ ing with oxide forms the univer¬ sally distributed earth, alumina, the chief constituent of clay, and an ingredient of many gums and minerals. This metal was origi¬ nally discovered in 1808, and Mr. Deville, a French chemist, has re¬ cently discovered a method of ob¬ taining it in large pieces, and a bar of it has been presented to the Polytechnic Institution in London by the Emperor Napoleon. The metal is coming into very general use by its becoming cheap. Its colour is white, with a faint blue tinge; it is highly malleable and ductile ; a perfect conductor of electricity; it melts at a tempera¬ ture higher than zinc (773°Fahr.), and resists the action of sulphu¬ retted hydrogen, of water, and of oxygen, if not heated. It is of very light weight, its specific gra¬ vity being only 2-60, that of gold being 19-26, and of iron 7*79. Alston Moor, in Northumberland. Mining in this district is of great antiquity: the miners of Alderston had their charter 600 years ago. These mines yielded gold, silver, and lead, but more of the last- named, and formerly belonged to Sir Edward Radcliffe,and remained in that family till the confiscation of the estates of James, Earl of _________— Derwentwater, in 1716. It was granted in 1734 to the Royal Hos¬ pital for Seamen at Greenwich. In form the manor of Alston Moor nearly resembles a square of about 6| miles, containing about 45 square miles, or 29,000 acres. The mines were yielding Green¬ wich Hospital in 1821 annually £100,000, and the lands £12,000. Alveus, in hydrography, the channel or belly of a river. Amaasa, such pieces of glass as are used in enamelling. Amalgam, a mixture of mercury with any other metal, tin, lead, etc. Ambitus, an enclosure : more particu¬ larly applied to the space around a building, as a churchyard, or a castle-yard. Ambo, Ambone, a rostrum or raised platform. Ambulatio, walks, or places of exer¬ cise, according to Vitruvius, adja¬ cent to theatres. Ambulatory, a cloister, gallery, or alley. American wood-boring tools. Some most efficient tools for boring in wood have been invented by Dr. Brown, of the United States, which appear, from the facility with which they may be worked, and the ex¬ cellent character of their perform¬ ance, likely to supersede entirely the old-fashioned ‘ auger” which is now in use in this country. The form of the implements has been borrowed from the boring appa¬ ratus with which the tiny insects who make such havoc in timber are provided. Amethyst, in heraldry, is a purple colour in noblemen’s coats of arms. Ammailare, to enamel. Ammoniac, a gum used for metallic vessels. Amphiprostyle, a term applied to a temple with a portico in front and also behind. Amphitheatre, an edifice formed by the junction of two theatres at the proscenium, so as to admit of seats all round the periphery. 12 Amphitheatre, in Roman antiquity, a large edifice of an elliptic form, with a series of rising seats or benches disposed around a spacious area, called the arena, in which the combats of gladiators and wild- beasts, and other sports, were ex¬ hibited. It consisted exteriorly of a wall pierced in its circumference by two or more ranges of arcades, and interiorly of vaulted passages radiating from the exterior arcades towards the arena, and several tranverse vaulted corridors which opened a free communication to the stairs at the ends of the passage and to every other part of the building, the corridors and ranges of seats forming elliptical figures parallel to the boundary wall. Amphithura, in the Greek Church, the veil or curtain opening to the folding doors, and dividing the chancel from the rest of the church. Amphora (pi. amphorae), an earthen vase or jar, with a handle on each side of the neck: among the an¬ cients, the usual receptacles of olives, grapes, oil, and wine. Hence, in decoration, amphoral means, shaped like an amphora or vase. Amulet, in decoration, a figure or cha- racter to which miraculous powers were supposed to be attached, and which particularly distinguished the buildings of Egypt. Amussium, anciently a carpenter’s and mason’s instrument, the use of which was to obtain a true plane surface; but the statements of the ancient writers render its construc¬ tion extremely difficult. Anahathra, steps to any elevated situ¬ ation, as the anabathra of theatres, pulpits, etc. Anabathrum, a pulpit, desk, or high seat. Anacampteria, the lodgings of per¬ sons who fled for sanctuary t© pri¬ vileged religious houses. Anacamptics, the doctrine of reflected light. Anachorita, the cell of a hermit. Anaclastics, the doctrine of refracted light. Anaglyph, an engraved, embossed, or chased ornament. Anaglypha, chased or embossed ves¬ sels made of bronze or the precious metals, which derived their name from the work on them being in relief, and not engraved. Anaglyphic work, a species of sculp¬ ture wherein figures are made pro¬ minent by embossing. Analemma, a projection of the meri¬ dian ; used also to designate a wall, pier, or buttress. Analogium, a tomb over the bodies of saints; also a term formerly applied to pulpits wherein the gospels and epistles were read. Anamorphosis, a distorted piece of perspective, occasioned by too near a point of view, and from the inju¬ dicious attitude or situation of the object, but perfectly true accord¬ ing to the laws of perspective. Anchor, an instrument used for the mooring of ships ; in architecture, a decorative moulding used in the orders, and applied to the echinus ; also an ornament in the form of the fluke of an anchor, frequently cut in the ovolo of Ionic capitals, and in the bed-mouldings of Ionic and Corinthian cornices. Anchor-stock, in ship-building, a me¬ thod of working planks, by which the abutments are to be disposed near the middle of those planks which are above or below them. Ancon, in decoration, a carved drink¬ ing-cup or horn ; an elbow or angle, or corner-stone. The An¬ cona foot measure is l - 282 of an English foot. Ancone, a console or ornament cut on the key-stone of an arch. Ancones, trusses or consoles employed in the dressings of apertures; also used to signify the corners or quoins of walls, cross-beams, or rafters, etc. Andirons, iron bars with legs to sup¬ port logs of wood in fire-places. Android, in mechanics, an automaton. 13 AND ANNULAR ENGINE. ANN Andron, an apartment, cloister, or gallery, assigned to the male part of a monastic establishment; ap¬ plied also to the space in a church by which the men were separated from the women. Anemography, a description of the winds. Anemometer, an instrument for mea¬ suring the force of the wind. Anemoscope, a machine to denote the changes of the wind or wea¬ ther. Angiportum, among the ancients, a narrow lane between two rows of houses. Angle, in geometry, the mutual in¬ clination of two lines meeting in a point. Angle-bar, in joinery, the upright bar at the angle of a polygonal win¬ dow. Angle-bead, a vertical bead, com¬ monly of wood, fixed to an exte¬ rior angle, and flush with the sur¬ face of the plaster, etc. of rooms, arches, etc. Angle-brace, in carpentry, timber fixed to the two extremities of a piece of quadrangular framing, making it to partake of the form of an octagon. Angle-bracket, a bracket placed in the vertex of an angle, and not at right angles with the sides. Angle-capital, used in Ionic capitals to the flank columns which have their volutes placed at an angle of 45° with the planes of the front and returning friezes. Angle-float, in plastering, a float made to any internal angle to the planes of both sides of a room. Angle-modillion, a modillion placed in a direction parallel to a diagonal drawn through a cornice at its mitring. Angle-staff, vertical head, generally of wood, fixed to exterior angles of a building flush with the service of the plaster. Angle of application, the angle which the line of direction of a power gives the lever it acts upon. Angle of inclination, the angle an in¬ clined plane makes with the horizon. Angle of traction, the angle which the direction of a power makes with the inclined plane. Angular modillions, those which are placed at the return of a cornice in the diagonal vertical plane, pass¬ ing through the angle or mitre of the cornice. Angular perspective, a term applied to the horizontal lines, both of the front and end of a building, con¬ verging to vanishing points, and terminating in the horizon; it is sometimes called oblique perspec¬ tive. Anlace, a falchion or sword, shaped like a scythe. Annealing, the process of softening and restoring the malleability of metals, by heating and allowing them to cool very slowly; and by which means glass, cast-iron, and steel, may be united to other sub¬ stances. Annatto, in chemistry, a reddish-yel¬ low vegetable dye, obtained from the seeds of the Bixa Orellana, and used for colouring cheese. Annicut, the Hindostanee term for a weir or dam : it is a stoppage built out in a river from a bank, as a pier or breakwater, and made use of in the Indian rivers to intercept the current of the stream, and di¬ vert a portion of its waters into channels or reservoirs for agricul¬ tural purposes. Annular engine, a direct-action ma¬ rine engine, having tw r o concentric cylinders; the annular space is fitted with a piston which is at¬ tached to a T-shaped cross-head by two piston-rods : the cross-head is formed by two plates with a space between for the connecting-rod to vibrate, and the lower end slides within the inner cylinder, and is connected to the crank. This ar¬ rangement has been patented by Messrs. Maudslay. Annular vault, a vaulted roof sup¬ ported on circular w r alls. 14 ANN ANTEJb'lXJS. ANT Annul.ittd columns , those clustered together or joiued by rings or bands. Annulet, in architecture, a small square member in the Doric capi¬ tal ; also the name of a small flat moulding. Anston, a parish in Yorkshire from whence the stone used for the Houses of Parliament has been brought. Antarala, the inner vestibule of a Hindoo temple. Antae, square pilasters terminating the walls of a temple: when a temple had no portico in front, two columns were made to intervene between the antse, and the aspect of the temple was said to be in antis. Antechamber, a room or passage to an inner chamber, for the accom¬ modation of servants and persons in waiting. Ante-capitulum, part of a cloister be¬ fore the door of a chapter-house. Anlefixae (by some called Greek tiles), upright ornamental blocks placed at intervals on the cornice along the side of a roof, to conceal or rather terminate, the ridges formed by the overlapping of the roof-tiles; also heads of lions, etc., for water¬ spouts below the eaves of temples. Antemural, a term applied to the outward wall of a castle; or that which separates a presbytery from a choir; also to a barbican en¬ trance before a castle. Antepaymenta, or Antepagmentum, the jamb of a door-case. Ante-parallels, in geometry, lines which make equal angles with two other lines, but in a contrary direc¬ tion. Ante-portico, a term sometimes used to denote an outer porch or vesti¬ bule ; the propyleeum in classic architecture. An ter ides, buttresses for strengthen¬ ing walls. Ante-solarium, a balcony facing the sun. Ante-venna, an awning or projecting roof of woodwork; a wooden or pent-house before a shop. Anthepsa, a Grecian vessel used for boiling water or keeping it hot; a cooking utensil. Anthracite, a coal not bituminous, found principally in South Wales and in the United States. Antics, in architecture,figures of men, beasts, etc., placed as ornaments to buildings. Anticum, a porch before a door. Antilia, an ancient machine similar to the modern pump. Antimensium, a portable altar or con¬ secrated table, used as a substitute for a proper altar. Antimeter , an optical instrument for measuring angles. Antimony, a metal usually found in a crude state combined with sulphur, of a bluish-white colour, crystal¬ line texture, brittle, and easily pul¬ verized : it does not oxidate at ordinary temperatures in the air, but, when heated, it burns with a light flame, producing the oxide; it fuses at 800°, and volatilizes at a white heat. Antimony yellow, a preparation of antimony, of a deeper colour thaq Naples yellow, and similar in its properties: it is principally used in enamel and porcelain painting, and is very various in tint; that of a bright colour is not affected by foul air, although blackened by sugar of lead. Antipayments, ornaments in carved work on the architrave, jambs, posts, or puncheons of doors. Antiquarium, a repository for antique monuments. Antoine (J. D.), born in Paris in 1733; became in after-years an architect of a high position; built several noble edifices, in Paris principally; died in 1807. Antrellum, a small grave or grotto; also a small temple. Antrum, an early temple for Christian worship. Antrum tumbale, a sepulchral cave or grotto. 15 ANT AFPIAN WAY. APT Antwerp bine, light-coloured, and somewhat brighter than Prussian blue, or ferro-prussiate of alumine, having more of the terrene basis, but all the other qualities of that pigment, except its extreme depth. Haarlem blue is a similar pigment. Antwerp brown, a preparation of as- phaltum, ground in strong drying oil, by which it becomes less liable to crack. Anvil, a large block of iron with a very hard, smooth, horizontal sur¬ face on the top, in which there is a hole at one end, for the purpose of inserting various tools, and a strong steel chisel, on which a piece of iron may be laid, and cut through by a blow with a hammer. The best anvils are faced with steel. This steel facing is shaped, heated, and laid on the anvil at a welding heat, the facing, however, being less heated than the anvil, and hammered rapidly until it is closely united ; the whole is then finished by repeated heatings and hammer¬ ings. The anvil is next hardened by raising it, but especially the face, to a full red heat, and quench¬ ing it in a large quantity of cold ■ water. It is of importance to cool it rapidly, and for this purpose a stream of water is to be preferred. Should the steel facing not crack by this process, it is ground until it is perfectly even, and the edges are made sharp or round as required. A-peek, a nautical term imph ing that the cable is hove taut, so as to bring the vessel nearly over her anchor : the yards are a-peek when they are topped up by contrary lifts. Aperture, an opening in a wall, door¬ way, or window. Apex, the top or highest point of a cone, mountain, pyramid, spire, roof, etc. Apiary, a place where bees are kept. Aplome, a mineral of a deep orange- colour. Aplustre, in early naval architecture, a carved tablet fixed on the extre¬ mity of a ship’s head, or ensign. Apudyterium, a dressing-room or anteroom to a bath in lloman vil¬ las, contiguous to the laconicum. Apopliyye, in architecture, that part of a column between the upper fillet of the base and the cylindrical shaft, which is usually curved into it by a concave sweep or inverted caveito. Apostles (the), in the tables of sym¬ bols of the early ages, were repre¬ sented by twelve sheep or lambs issuing from Bethlehem and Jeru¬ salem, cities of Christ’s birth and death. Apotheca, a place in the upper part of the house, in which theRomans fre¬ quently placed their wines in earth¬ en amphoiae; also an apothecary’s shop, a cabinet, storehouse, etc. Apothesis, a recess on the south side of the chancel of a church, fitted up with shelves for books, vest¬ ments, etc. Apparatus, a term denoting a com¬ plete set of instruments belonging to an artist or a mechanist. Appian Way, a celebrated road lead¬ ing from Rome to Brundusium: so named from Appius Claudius. Appii forum, the forum built by Ap¬ pius, the Roman consul, about fifty miles distant from Rome, near the modern town of Piperno, on the way to Naples. The uses to which the Romans applied the forum were so various, that it is not easy to as¬ certain the nature of the building. It might have been a place for the distribution of justice, or for hold¬ ing a market. The ‘Three Ta¬ verns’ were nearer to Rome than the Appii Forum, as Cicero inti¬ mates, who, in going from Rome, a little before he came to the fo¬ rum of Appius, arrived at the Three Taverns : so that probably the chief number of Christians waited for the Apostle Paul at a place of refresh¬ ment, while some of their number went forward to meet him, and respectfully to acquaint him with their expectation of seeing him among them. 16 ARCADE. APP Apple-tree, a wood generally hard and close, and of reddish-brown tints, used commonly in Tunbridge tur¬ nery, etc. Apricot-tree, a native wood of Arme¬ nia, used by the French in turnery. Apron, the sill or lower part of a win¬ dow; a platform or flooring of plank raised at the entrance of a dock: in naval architecture, a piece of curved timber fixed behind the lower part of the stern of a ship. Apsis, the east end of a church or chancel; sometimes applied to a canopy over an altar; also to a circle about a star or planet. Apsis gradata, a bishop’s throne in cathedral churches. Aqua fortis, in chemistry, nitric acid diluted : the more concentrated is named spirit of nitre. Aquamale, a holy-water basin. Aqua regia, nitro-muriatic acid; a compound of two parts nitric acid and one part muriatic acid. Aquatinta, in the arts, engraving which resembles drawings in In¬ dian ink. Aqueduct, a conduit for water: a con¬ struction of stone or timber, built on uneven ground, to preserve the level of water, and convey it by a canal from one place to another. Aquemola, a water-mill. Aquila, a reading-desk, so called from its shape being that of an eagle with extended wings, supported by a pedestal. Arabesque, generally applied to a style of ornament for pilasters, friezes, etc., as those painted by Raffaelle in the Vatican. Arabo-tedesco, a term applied to the Moorish style of buildings in Spain, etc. Ara dignitatis, an altar at which none but the highest ecclesiastics per¬ form divine rites. Arceostyle, in architecture, the great¬ est interval or distance which can be made between columns, that is, eight modules or four diameters ; also a species of temple which has its columns placed widely asunder. ARC Arbor, a spindle or axis upon which a ring or wheel is turned in a lathe. Arbor Diance, in chemistry, crystals formed by the combination of sil¬ ver and mercury. Arbores, brass branches for lights sus¬ pended from ceilings. Arboretum, a grove of trees in a park, pleasure-ground, or garden. Arbor vitae, a tree which attains to a height of from 40 to 50 feet; its wood is of a reddish colour, very light, soft, and fine-grained, and is much used in house carpentry. Arc, in geometry, part of the circum¬ ference of a circle, or any curve lying between two points; a bow, vault, or arch. Area, a place in a vaulted chamber for sepulchral purposes; an exca¬ vation before the basement story of a house; an enclosed space; a chest in which the Romans depo¬ sited their money: the word is also used to signify a beam of wood which has a groove or channel hol¬ lowed in it from one end to the other. Arcade, a series of recesses with arched ceilings or soffits ; a covered passage: in modern appliances, a vaulted avenue, now much in vogue, more particularly in Paris.—Ar¬ cades, though less magnificent than colonnades, are of extraordinary beauty when well contrived, afford¬ ing shade from the sun and shelter f«om the rain. Though not so mag¬ nificent as colonnades, they are stronger, more solid, and less ex¬ pensive. They are proper for tri¬ umphal entrances, gates of cities, of palaces, of gardens, and of parks; for public squares, markets, or large courts in general, and for all aper¬ tures that require an extraordinary width. Their ornaments. —The piers of arcades may be decorated with columns, pilasters,niches, and aper¬ tures of different forms. The arch itself may be turned either with rock worked or plain rustic arch- stones or voussoirs, or with an 17 ARCH. ARC archivolt properly moulded. The keystone is generally carved in the form of a console, or sculptured with some head, or the like. The archivolt springs from an impost or plat-band, or sometimes from co¬ lumns ; but this is not to be prac¬ tised except in cases of the most urgent nature, for its makes neither substantial nor beautiful work. In arches that are of large dimen¬ sions, the keystone should never be omitted ; its carving, however, may be dispensed with, if expense be an object. When the piers are deco¬ rated with disengaged columns, the entablature must break round over the columns; and the columns, whether eugaged or not, should stand either on a pedestal or high plinth, by which means they will not only be kept dry, but their bases will likewise be protected from accidental damage.—Arches must always rise from an impost or a plat-band; and if there be no keystone to the archivolt, its sum¬ mit should be kept down from the under side of the architrave of the accompanying order, at least half the distance that it would be, were a keystone employed, in order that the disagreeable appearance of the acute angle which it would other¬ wise form with the architrave may be avoided. Their proportions. — The height of arches to the underside of their crowns should not exceed twice their clear width, nor should it be much less; the piers not less than one-third the breadth of the arch, nor more than two-thirds; but the piers at the angles should be wider than the other piers by one-half, or one-fourth at least. Area, in Roman architecture, the gutters of the cavedium. Arc-boutant, a kind of arched but¬ tress formed of a flat arch, or part of an arch, and abutting against the feet or sides of another arch or vault, to support them, and prevent them from bursting or giving way. ARC Arcella, in mediaeval architecture, a cheese-room. Arch, the curved part of a building, supported at its extremities only, and concave towards the earth ; a vaulted roof, or dome, constructed either with bricks, stone, or other materials : the arch of a bridge is formed of segments of a circle, elliptical or catenarian; in Christian architecture,arches display twenty- two varieties of form. — Arches are used in large intercolumni- ations of spacious buildings; in porticoes, both within and without temples; in public halls, as ceil¬ ings, the courts of palaces, cloisters, theatres, and amphitheatres : they are also used to cover the cellars in the foundations of houses and pow¬ der-magazines ; also as buttresses and counterforts, to support large w^alls laid deep in the earth; for triumphal arches, gates, win¬ dows, etc.; and, above all, for the foundations of bridges and aque¬ ducts : they are supported by piers, abutments, imposts, etc.—Arcbes are of several kinds, circular, ellip¬ tical, cycloidal, catenarian, etc., ac¬ cording as their curve is in the form of a circle, ellipse, cycloid, cate¬ nary, etc. Arches are to be found in the Greek theatres, stadia, and gymnasia, some of them erected probably 400 years before Christ. The most ancient arches of which we have correct data are those of the cloacae at Rome. The Emperor Hadrian threw a bridge over the Cephisus, between the territories of Attica and Eleusis, on the most frequented road of Greece. Arch (theory of the). This important subject has exercised the talents and ingenuity of some of the great¬ est mathematicians in modern times, and many different solutions have been given to the various pro¬ blems connected with it; but, as the greater partof them are founded on suppositions that have no exist¬ ence whatever either in nature or practice, they have had a tendency 18 ARCH. ARC rather to mislead than direct those •who are engaged in the operations of bridge-building. Dr. Olinthus Gregory, in the preface to his ex¬ cellent work on ‘Mechanics,’ states, that “theoretical and practical men will most effectually promote their mutual interests, not by affecting to despise each other, but by blend¬ ing their efforts ; and further, that an essential service will be done to mechanical science, by endeavour¬ ing to make all the scattered rays of light they have separately thrown upon this region of human know¬ ledge converge to one point. Gauthey, speaking of the theory of La Hire, observes that such analy¬ tical researches are founded on hy¬ potheses which every day’s experi¬ ence contradicts. The following are the principal writers on the equili¬ brium of the arch. In 1691, the ce¬ lebrated mathematicians, Leibnitz, Huygens, James and John Ber¬ noulli, solved the problem of the catenary curve: it was soon per¬ ceived that this was precisely the curve that should be given to an arch of which the materials were in¬ finitely small and of equal weight, in order that all its parts may be in equilibrium. In the ‘ Philoso¬ phical Transactions’ for the year 1697, it is stated that David Gre¬ gory first noticed this identity; but his mode of argument, though suf¬ ficiently rigorous, appears not to be so perspicuous as could be desired. In one of the posthumous works of James Bernouilli, two direct solu¬ tions of this problem are given, founded on the different modes of viewing the action of the voussoirs : the first is clear, simple, and precise, and easily leads to the equation of the curve, which he shows to be the catenary inverted; the second requires a little correction, which Cramer, the editor of his works, has pointed out. In 1695, La Hire, in his ‘ Treatise on Mecha¬ nics,’ laid down, from the theory of the wedge, the proportion accord- ARC ing to which the absolute weight of the materials of masonry ought ro be increased from the keystone to the springing in a semicircular arch. The historian of the ‘ Acade¬ my of Sciences’ relates, in the vo¬ lume for the year 1704, that Parent determined on the same principle, but only by points, the figure of the extrados of an arch, the intrados being a semicircle, and found the force or thrust of a similar arch against the piers. In the ‘ Memoirs of the Academy of Sciences’ for the year 1712, La Hire gave an inves¬ tigation of the thrusts in arches under a point of view suggested by his own experiments : he supposed that arches, the piers of which had not solidity enough to resist the thrust, split towards the haunches at an elevation of about 45 degrees above the springings or impost; he consequently regarded the upper part of the arch as a wedge that tends to separate or overturn the abutments, and determined, on the theory of the wedge and the lever, the dimensions which they ought to have to resist this single effort. Couplet, in a memoir composed of two parts, the first of which was printed in the volume of the Aca¬ demy for 1729, treats of the thrusts of arches and the thickness of the voussoirs, by considering the mate¬ rials infinitely small, and capable of sliding over each other without any pressure or friction. But, as this hypothesis is not exactly conform¬ able to experiment, the second part of the memoir, printed in the vo¬ lume for 1730, resumes the ques¬ tion by supposing that the mate¬ rials have not the power of sliding over each other, but that they can raise themselves and separate by minute rotatory motions. It can¬ not however be said that Couplet has added materially to the theo¬ ries of La Hire and Parent, and none of them treated the subject, either in theory and practice, in such a satisfactory manner as was 19 ARCH. ARC afterwards done by Coulomb. Sub¬ sequently a memoir was published by Bouguer on the curve lines that are most proper for the formation of the arches of domes. He con¬ siders that there may be an infinite number of curve lines employed for this purpose, and points out the mode of selecting them. He lays it down uniformly that the voussoirs have their surfaces infi¬ nitely smooth, and establishes, on this hypothesis, the conditions of equilibrium in each horizontal course of the dome, but has not given any method of investigating the thrusts of arches of this kind, nor of the forces that act upon the masonry when the generating curve is subjected to given conditions. In 1770, Bossut gave investigations of arches of the different kinds, in two memoirs, which were printed among those of the Academy of Sciences for the years 1774 and 1776 : he appears to have been engaged in this in consequence of some disputes concerning the dome of the French Pantheon, begun by the celebrated architect Soufflot, and finished from his de¬ signs. In 1772, Dr. Hutton pub¬ lished his principles of bridges, in which he investigated the form of curves for the intrados of an arch, the extrados being given, and vice versa. He set out by developing the properties of the equilibrated polygon, which is extremely useful in the equilibrium of structures. Mr. Attwood has written a disserta¬ tion on the construction of arches on the same principles as La Hire. Arch, in architecture, a concave struc¬ ture raised or turned upon a mould, called the centering, in form of the arc of a curve, and serving as the inward support of some superstruc¬ ture. Sir Henry Wotton says, “ An arch is nothing but a narrow or contracted vault; and a vault is a dilated arch.” Arch, in geometry, a part of any curved line, as of a circle or ellipsis. ARC Arch, in masonry, a part of a building suspended over a hollow, and con¬ cave towards the area of the hol¬ low: the top of the wall or walls which receives the first archstones is technically called the abutment or springing. Arch, in mining, a piece of ground left unworked. Arch-band, applied by workmen to that portion of an arch or rib which is seen below the general surface of vaulting. Arch-briclc, a wedge-shaped brick employed in the construction of arches. Arch-buttress, a piece of insulated masonry usually named a flying- buttress, extending from the clere¬ story of a church and over the roof of its aisle, where it rests on the buttress of the outer wall. Arch of equilibration, that which is in equilibrium in all its parts, having no tendency to break in one part more than in another. Arch, triumphal, a building of which an arch is the principal feature, usually raised to commemorate some great achievement. Archaeology, the study of ancient art, but more particularly that of the middle ages. Arched, in mining: the roads in a mine, when built with stones or bricks, are generally arched level drifts. Archeion, a recess in a Grecian tem¬ ple, for the reception of the trea¬ sures of the deity to whom the temple was dedicated. Archeion, in Athens, the office in which the decrees of the people and other state documents were preserved. Arches, Norman, semicircular, which form continued to the latest date of this style, and is frequently in¬ termixed with pointed arches, even when other parts had advanced into the next style, of which the Temple Church is an instance. There are some Norman arches more than a semicircle,—the horse- 20 ARC ARCHITECTURE. ARC shoe,—and a few instances of a double arch. Archetus, a saw for cutting stones: Muratori used the term for a crane or pulley for raising stones to the upper part of a building. Archimedes screw-propeller, in 1836, was launched by T. P. Smith, pa¬ tentee. The vessel 232 tons, 125 feet long, 21 feet 10 inches beam, 80-horse power. Archimedean screw, a machine in¬ vented by Archimedes for raising water; also now applied to propel vessels through water. Archiepiscopal palace, the dwelling of an archbishop. Architect, a person skilled in the art of building ; one who forms plans and designs for edifices, conducts the work, and directs the secondary artificers employed; and whose emoluments are generally 5 per cent, on the amount of money ex¬ pended. Architecture, a science applicable to the art of constructing domestic, ecclesiastical, municipal, palatial, or other buildings, and the adorn¬ ment of the same according to the rules of the several orders, Doric, Ionic, and Corinthian, also the Tus¬ can and Composite, from Roman models, or other styles, each for its purpose, such as is usually called Gothic architecture, and modes subservient to climate and fashion, or caprice. “ Architecture,” says Palladio, “ being grounded upon rules taken from the imitation of Nature, admits of nothing that is contrary or foreign to that order which Nature has prescribed to all things. An architect is not re¬ strained from departing sometimes from common methods or usage, provided such variation be agree¬ able and natural.” The public at large has a claim over the architecture of a country. It is common property, inasmuch as it involves the national taste and character ; and no man has a right to pass off his own barbarous in- ventions as the national taste, and to hand dowm to posterity his ow u ignorance and disgrace to become a satire and a libel on the know¬ ledge and taste of his age. Architecture, the Orders of. — Among the ancients, the use of the orders was very frequent; many parts of their cities were provided with spa¬ cious porticoes, their temples were surrounded with colonnades, and their theatres, baths, basilic®, tri¬ umphal arches, mausolea, bridges, and other public buildings were profusely enriched with columns ; as were likewise the courts, vesti¬ bules, and halls of their private villas and houses. In pure architecture, says A. W. Pugin, the smallest detail should have a meaning or serve a purpose ; and even the construction itself should vary with the material em¬ ployed, and the designs should be adapted to the material in which they are executed. Strange as it may appear at first sight, it is in pointed architecture alone that these great principles have been carried out: we may be enabled to illustrate them from the vast cathedral to the simplest erec¬ tion. Moreover, the architects of the middle ages were the first who turned the natural properties of the various materials to their full account, and made their mechanism a vehicle for their art. The won¬ derful strength and solidity of their buildings are the result, not of quantity or size of the stones em¬ ployed, but of the art of their dis¬ position. The two following pages contain a synopsis of the proportions of the Orders, and of various exam¬ ples of each, compiled by Mr. W. H. Leeds for Pugin’s edition of Normand’s 1 Parallel of the Or¬ ders.’ 21 ARCHITECTURE. ARC ARC Names of the Orders. Base. Column. Capital. Archi¬ trave. Frieze. e H3 s' T3 s s •B s TUSCAN. 'B a A '£ a "S. s p. •B i cL *3 S 0. Palladio. 0 1 0 7 0 0 0 1 0 0 1 5 0 0 26 Scamozzi. 0 1 0 7 1 0 0 1 0 0 1 24 0 1 9 Serlio. 0 1 0 6 0 0 0 1 0 0 1 0 0 1 0 Vignola.. . . 0 1 0 7 0 0 0 1 0 0 0 25 0 1 5 DORIC. Parthenon at Athens .... 5 1 0 0 0 28 0 1144 0 1 194 Temple of Theseus, do. . . . 5 1 0 0 1 0 0 1 20 0 1254 Great Temple at Paestum . . . 4 0 15 0 1 n 0 1 114 0 1 24 Temple of Apollo, at Delos . . 5 0 25 0 0 284 0 1 20 0 1 7 Portico of Philip, do. . . . 6 0 20 0 0 16 0 1 9 0 1 14 Temple at Corinth. 8 0 10 0 0 25i 0 1 id . . Propylaeum at Athens .... 5 1 0 0 0 23 Portico of Augustus, do. . . . 6 0 0 0 0 23 0 1 16 Theatre of Marcellas, Rome . . Doric Order at Albano .... 7 1 18 0 1 24 0 1 1 7 1 0 0 1 0 0 1 0 0 1 15 Baths of Diocletian. 8 0 0 0 1 0 0 1 2 0 1 15 Palladio. 0 1 0 8 0 0 0 1 0 0 1 0 0 1 15 Scamozzi. 0 1 0 8 1 0 0 1 0 0 1 5 0 1 15 Vignola. 0 1 0 8 0 0 0 1 0 0 1 0 0 1 15 Viola ......... 0 1 0 8 0 0 0 1 0 0 1 0 0 1 15 Delorme. 0 1 0 8 0 0 0 1 0 0 1 0 0 1 15 IONIC. Temple on the Ilissus .... 0 1 0 8 0 0 0 1 94 0 1 25 0 1 19 Temple of Minerva Polias, Athens 0 0 25 9 1 0 0 1 134 0 1 214 0 1 184 Temple of Erechtheus, Athens . 0 0 234 9 0 0 0 1 10 0 0 283 Temple of Fortuna Virilis . . 0 1 0J 8 1 24 0 0 29 0 1 84 Theatre of Marcelius .... 0 1 0 9 0 0 0 1 14 0 1 13 0 1 6| Baths of Diocletian. 0 1 0 8 1 0 0 1 14 0 1 4 0 0 28 Palladio. 0 0 22 9 0 0 0 1 0 1 6 0 0 27 Scamozzi. 0 0 22 8 1 15 0 0 264 0 1 15 0 0 28 Vignola. 0 0 20 9 0 0 0 1 04 0 1 74 0 1 15 Serlio. 0 0 204 7 1 0 0 1 0 0 1 0 '0 0 224 Alberti. 0 0 224 8 0 0 0 1 14 0 1 0 0 1 0 CORINTHIAN. Lantern of Demosthenes, Athens 0 1 CD 10 0 0 1 0 24 0 1 21 0 1 94 Temple of Jupiter Olympius, do. 0 0 21 9 1 15 1 0 2 7 0 1 114 0 0 2/4 Incantada at Salonica .... 0 0 25 9 0 15 1 0 11 0 1 164 0 1 124 Arch of Theseus, Athens . . . 0 0 23 9 1 0 1 0 15 0 1 124 0 1 10 Temple of Jupiter Stator, Rome 0 0 20 10 0 64 1 0 64 0 1 134 0 1 13| Temple of Jupiter Tonans . . 0 0 224 10 0 15 1 0 10 0 1 124 0 1 13 Portico of the Pantheon . . . 0 0 24 9 1 164 i 0 74 0 1 123 0 1 94 Interior of the Pantheon . . . 0 0 23£ 9 1 44 1 0 124 0 1 12 0 1 12 Forum of Nerva ...... 1 0 18 0 1 14 0 1 15 Templeof Antoninus and Faustina Nero’s Frontispiece. .... 0 0 24 9 1 6 1 0 8J 0 1 134 0 1 lOf 0 0 204 10 0 0 1 0 16 0 1 H4 0 1 143 Arch of Constantine .... 0 0 24 9 1 7 1 0 63 0 1 15 0 1 10 Temple of Mars the Avenger. . 1 0 91 0 1 94 Basilica of Antoninus .... 0 0 23 10 0 lii 1 0 94 0 1 134 0 1 10 Temple of the Sibyl, Tivoli . . 0 0 164 9 0 25 1 0 0 0 1 0 0 1 9j Palladio ........ 0 1 0 9 1 0 1 0 0 0 1 8 0 0 23.1 Scamozzi. 0 1 0 10 0 0 1 0 0 0 1 12 0 1 2 Vignola. .. 0 1 0 10 0 0 1 0 0 0 1 15 0 1 15 Serlio. 0 1 0 9 0 0 1 0 0 0 1 0 0 1 7 Alberti .. 0 I 0 9 0 0 1 0 0 0 1 0 0 1 0 COMPOSITE. 16 Arch of Titus. 0 0 23 10 0 6 1 0 14i 0 1 0 1 14 Arch of Septimius Severus . . 0 0 20 9 1 10 1 0 54 0 1 15 0 0 25.1 Baths of Diocletian. 0 0 22 10 0 m 1 0 11 0 1 144 0 1 14 Palladio. 0 1 14 10 0 0 1 0 0 0 1 10 0 1 0 Scamozzi. 0 1 0 9 1 15 1 0 0 0 1 9 0 1 1; Vignola. 0 1 0 10 0 0 1 0 0 0 1 15 0 1 15 Caryatides of the Temple of 1 • • 5 0 0 0 0 27 0 1 254 ■ . . 22 ARCHITECTURE. ARC ,RC Cornice. Entabla¬ ture. Xnterco- umniation Diameter of column. g 5 i . 6 a. diam. p ‘d O a p< diam. 0 s Pr feet. inches. 0 1 134 1 1 144 0 i 11 1 1 224 0 1 0 1 1 0 0 I 10 1 1 10 0 0 26 2 0 0 2 0 20 6 0 0 254 2 0 11 2 1 6 6 1 * 0 0 28 1 1 12 2 0 10 7 0-03 0 1 74 2 0 2 0 25 0 0 25 1 1 18 3 1 5 2 5*10 2 0 15 4 4-05 0 1 63 1 1 233 0 1 5 1 1 20 0 1 16 2 0 3 0 1 8 1 1 23 2 1 15 0 l 17 2 0 7 4 0 11 0 1 15 2 0 0 0 1 10 1 1 25 . . . 0 1 10 1 1 25 • 0 1 2 2 0 16 2 0 15 1 9-4 0 1 74 2 0 174 3 0 0 2 9-4 1 1 20 2 3’8 1 o 104 2 0 17 * 2 1 5 3 2 1 0 6 2 0 25 f 0 1 16 1 1 18 . 0 1 16 l 1 19 2 0 74 0 1 12 1 1 25 0 1224 2 0 15 , . 0 1 2 1 0 244 . . 0 1 10 1 1 10 . . 0 1 20 2 0 204 2 0 6 1 2 0 1 18 1 1 27 3 0 0 ; 2 1*3 0 1 134 2 0 7\ 3 0 24 2 / 9 " 0 1 164 2 0 14 • / • 10 * 1 0 9i 2 1 1 I 5 4 0 1 164 2 0 n| 1 1 34 4 8* 0 1 24 2 0 164 2 0 15 4 11 0 1214 2 0 154 2 0 24 3 84 s 0 1254 2 0 bO OO , . 3 6 0 1224 2 0 164 1 1 14 4 10* 0 1274 2 0 264 1 1 0 0 1 284 2 0 234 2 11* 1 0 284 5 . 1 1 104 0 1 3 1 1 124 2 0 14 2 44 0 1 174 1 1 24 2 0 0 0 1 19 2 0 3 2 0 0 1 0 0 2 1 0 a 0 20 0 1 9 1 1 16 0 1 10 1 1 10 1 0 2 2 1 2 2 1 0 84 2 0 19 8 0 * 0 1 21 2 0 194 0 1 20 2 0 0 • s 0 1 163 1 1 27 t e - 1 0 0 2 1 0 * 1 0 0 1 1 254 . Architecture, qualities of. There is perhaps no subject on which persons are more apt to differ in their opinions than on the beauty of a building. In architecture the creative power of Nature herself is the model imitated. It is an art which, appeals directly to the un¬ derstanding, and has not the means of flattering the senses in the same way as the sister arts: hence its productions are not universally ap¬ preciated. The beautiful models of Nature, however, are the index and guide of the painter and sculp¬ tor : a successful imitation of these models, even without an advance on the part of the artist towards those higher intellectual beauties which distinguish the historical painter, is capable of affecting us with very agreeable sensations. The object of an artist’s inquiry is not so much to investigate meta¬ physically the cause of beauty in the productions of his art, as to study the effects that flow from those which by the common con¬ sent of ages are esteemed beautiful, and thus shorten his road by an a priori method. It is in this way that he will more readily obtain information on those qualities which act on the understanding and excite our affections by means of the beautiful result they exhibit. These qualities may be classed as follows Magnitude and solidity, as qualities which affect the eye. Order and harmony, as quali¬ ties which affect the understanding. Richness and simplicity, as qualities which excite the affec¬ tions,—-in which taste is the prin¬ cipal guide. These qualities an¬ swer to the three divisions which those who have written on archi¬ tecture have usually adopted, namely— Construction, in which the chief requisites are solidity and strength. Design or disposition, in ARCHITECTURE. ARC ARCHITJ SCTURE. ARC which the principal requisites are order and harmony. Decoration, whose requisites are richness or simplicity, accord¬ ing to the nature of the composi¬ tion. That there are, however, many other circumstances which tend to the production of an agreeable and , beautiful result, is sufficiently ob¬ vious : one of them should be more particularly noticed, because there can be no doubt of its influence in the excitement of our admiration of the splendid monuments of Gre¬ cian art; it is an association with the times and countries which are most hallowed in our imagination. It is difficult for us to see them, even in their modern copies, with¬ out feeling them operate upon our minds, as relics of those polished nations where they first arose, and of that great people by whom they were afterwards borrowed. The business of an architect re¬ quires him rather to be a learned judge than a skilful operator; and when he knows how .to direct and instruct others with precision, to examine, judge, and value their performances with masterly accu¬ racy, he may truly be said to have acquired all that most men can ac¬ quire : there are but few instances of such prodigies as Michael An¬ gelo Buonarroti, who was at once the first architect, painter, geome¬ trician, anatomist, and sculptor of his time. Vitruvius furthermore observes, that an art enriched with such variety of knowledge is only to be learned by long and constant appli¬ cation ; 'and advises his contempo¬ raries never to assume the title of architects till they are perfect mas¬ ters of their own profession, and of the arts and sciences with which it is connected ; a caution that even in the present, times may perhaps not be unnecessary. Architecture, Naval, the art of con¬ structing ships and vessels to float on the waters. Naval architecture has suffered more than most other sciences by the arbitrary 'systems of those interested in its improve¬ ment. Disregarding the fundamen¬ tal principles of all floating bodies, and too hastily giving up as hope¬ less the attainment of a theory combining experiment with esta¬ blished scientific principles, they have contented themselves with ingeniously inventing mechanical methods of forming the designs of ships’ bodies, which they did not even pretend to prove had any connection with the properties of the machine necessary to insure the qualities conducive to its in¬ tended use. For instance, some invented methods of forming ships’ bodies of arcs of circles ; others, of arcs of ellipses, parabolas, or of whatever curve they might arbi¬ trarily assume. They did not at¬ tempt to show that these curves possessed any property which would render a ship a faster sailer, a more weatherly or safer ship, than any other curves which might have been adopted in the construction of the ship’s body. Architholus, a round chamber, the sudatorium of a Roman bath. Architrave, the lower of the three principal members of the entabla¬ ture of an order, being the chief beam resting immediately on the column. Architrave cornice, an entablature consisting of an architrave and cor¬ nice only, without the interposition of a frieze. Architrave doors, those which have an architrave on the jambs and over the door. Architrave windows, of timber, are usually an ogee raised out of the solid timber, with a roll over it. Archivolt, a collection of members in the face of an arch, concentric with the intrados, and supported by imposts. Archivolt of the arch of a bridge,— 1 the curve line formed by the upper 24 A UR ARK. ARC sides of the arch-stones in the face of the work ; it is sometimes un¬ derstood to be tiie whole set of arch-stones which appear in the face of the work. Archivultu.nl, a cesspool or common sewer. Archway, an aperture in a building covered with a vault. Arcs doubleaux, a French term for arch-bands, and employed by Eng¬ lish writers from the time of De POrme, etc. Arcunio (M.), born in Rome, was both an architect and.painter, died about 1640. Arcula, a small coffer or box. Arcus, an area in the form of an ancient basilica. Arcus, an arch ; a true arch is formed of a series of wedge-like stones or of bricks supporting each other, and all bound together by their mutual pressure. Arcus-toralis, in medieval architec¬ ture, the lattice separating the choir from the nave in a basilica. Arcutio, a machine consisting of hoops. Ardeme (John) was clerk of the work at the building of the monu¬ ment in Westminster Abbey Church to King Henry V., who died in 1422. Ardesia, a slate used in Italy for covering roofs. Area, in geometry, the superficial content of any figure. Areas, in computing the superficial content of land, are generally ex¬ pressed in statute acres, roods, and perches. The acre is equal to 10 square chains of 66 feet, or 22 yards in length. Area drain, a narrow area drain not covered, on the basement floor of a building, to remedy or prevent dampness in the connecting walls. Area wall, the wall which forms the sides of an area. Arena, the area or floor of an amphi¬ theatre. Arenarium, an amphitheatre, ceme¬ tery, crypt, or sepulchre. Areometer, an instrument for measur¬ ing the density or gravity of fluids. Areupayus, the court in which the Areopagites, or supreme judges of Athens, assembled. Areostylos, intercolumniations, when their distance from each other is four diameters. Arerde, reared, built, or raised up. Argand lamp, a lamp with a circular wick, through which a current of air passes. Aryyrocopewn, the mint at Athens. Arislotele (G.F.),architect and sculp¬ tor, commenced, from the designs of Raffaelle, the Palazzo Pandol- fini at Florence ; he died in 1530. Ark, a shelter, a place of protection from floods ; in the time of Moses, a coffer or sort of bark, in shape and appearance like a chest or trunk ; also described by Moses as a little wicker basket, in which he was exposed on the Nile. The ancients inform us that the Egyp¬ tians used on the Nile barks made of bulrushes. Ark, a chest used in farm-houses for. keeping meal or flour. Armarium, a niche or cupboard near the side of an altar. Armenian architecture, the edifices in Armenia, erected previously to the cultivation of a Graeco-Roman architecture, supposed a.it. 260 — 314 . Armilla, an ornament w’orn by Greek men and women as a bracelet or an armlet. Aimour, a defensive clothing of metal. Armoury, a storehouse or room in which armour is preserved. Arnatto (colour), the name of a ve¬ getable substance from the West Indies, of an orange-red colour, soluble in water and spirit of wine, principally used by the dyer, and in colouring cheese. It is also an ingredient in lacquering. Aronude, embattled, a junction of several lines forming indentations. Arrayonite, a remarkable form of carbonate of lime, found in difler- 25 C ARR ART ART AND ent shapes, from hexagonal pris¬ matic crystals of coralloid masses. Arris, in joinery and masonry, tiie line of concourse, edge, or meeting of two surfaces. Arris fillet, a slight piece of timber of a triangular section, used in raising the slates against chimney- shafts, etc. Arris gutter, a wooden gutter of the V form, fixed to the eaves of a building. Arris-wise, in bricklaying, tiles laid diagonally. Arshin, a Russian measure of length, equal to 2j feet English. Arsenal, a building for naval or mili¬ tary stores. Arsenic, a metal of a crystalline appearance, and very brittle. It sublimes out of the air unchanged at 360°, but in air it is oxidated, and becomes arsenious acid : it is occasionally found alone, but is generally combined with nickel, cobalt, and other metals. Art and Science are necessarily very closely allied, but their points of difference are sufficiently manifest. Dr. Whewell, in his ‘ History of the Inductive Sciences,’ defines Science as exact, general, specu¬ lative knowledge. ‘ The object of Science,’ he says, ‘is knowledge ; the object of Art is work. The latter is satisfied with producing its material results ; to the former the operations of matter, whether natural or artificial, are interesting only as far as they can be em¬ braced by intelligible principles. The end of Art is the beginning of Science ; for when it is seen what is done, then comes the question why it is done. Art may have fixed rules stated in words, but she has these merely as means to an end ; to Science the propo¬ sitions which she obtains are each in itself a sufficient end of the effort by which it is acquired. When Art has brought forth her products her task is finished ; Sci¬ ence is constantly led by one step | SCIENCE. of her path to another ; each pro¬ position which she obtains impels her to go onwards to other propo¬ sitions more general, more pro¬ found, more simple. Art puts elements together without caring to know what they are or why they coalesce. Science analyses the compound, and at every step strives not only to perforin, but to understand the analysis. Art ad¬ vances in proportion as she be¬ comes able to bring forth products more multiplied, more complex, more various ; but Science reckons her success in proportion as she sees in all the phenomena the results of one or two simple and general laws. Artesian wells, so called from a mode practised at Artois, in France, in boring for water. Arthur’s oven : According to the tes¬ timony of Boethius, we had a spe¬ cimen of one of the Roman temples in Britain, built in the time of Ves¬ pasian, remaining in that singular little structure cal led Arthur’s oven, not far from theWall of Antoninus. He says, according to tradition, there was an inscription on a stone declaring that the building was erected by Vespasian, in honour of the Emperor Claudius and the God¬ dess Victory. It had a tesselated pavement. It was 19 feet 6 inches in diameter within, arched towards the top, with a round aperture (like that of the Pantheon at Rome) in the midst of the dome 11 feet 6 inches diameter, and the utmost height to the periphery, or edge of this aperture, from the floor, 22 feet (query, within or without, i. e. the lowest or highest periphery of the aperture?). At a little distance from the top, beneath the circular opening in the midst of the dome, was a small square window on one side, and round the inside, resting on the floor, were stone seats, and against the wall on the south side an altar ; the door of entrance, which had a 26 ARTIFICER. ASS ART regular Roman arch, being placed under the square window. Arthur’s oven was pulled down about 1743, by Sir Michael Bruce of Stonehouse, near Falkirk, for the sake of the stones; but with little profit to himself, for the stones were used in constructing a mill- dam, which was soon carried away by a flood. See the ‘ Antiquarian Repertory,’vol. iii. p. 73; also Pen¬ nant’s ‘ Tour in Scotland,’ pt. i. p. 242, and pt. ii. p. 228; and General Roy’s ‘ Military Antiqui¬ ties,’ pi. 36 ; and Gordon’s ‘ Itiu. Septentr.,’ p. 24, tab. Few Roman arches existing in Britain,—few, it appears probable, were ever erected in it by that people, and those of no great mag¬ nificence,—the arch was probably a recent invention when the Ro¬ mans had possession of this island. Artificer, one who possesses a supe¬ rior knowledge as an artist or ma- ! nufacturer. Asarotum, a kind of chequered pave¬ ment used by the Romans. Ash, a superior wood, of British growth, of a brownish white with a shade of green: it is tough and elastic, and superior to any other wood exposed to sudden shocks i and strains; used for frames of machines, wheel carriages, inside work of furniture, etc. Asheley (Hector), a famous master mason in the times of Henry VII. and VIII. Ashlar, a term applied to common or freestones as they come out of the quarry. By ashlar is also meant the facing of squared stones on the front of a building: if the work be so smoothed as to take out the marks of the tools by which the stones were first cut, it is called plane ashlar; if figured, tooled ash¬ lar, or random tooled, or chiselled, or bousted, or pointed: if the stones project from the joints, it is said to be rusticated. Ashlar, or Achelor, hewn stone, used for the facings of walls. Ashlering, in carpentry, the fixing ol short upright quarterings between the rafters and the floor. Ash-pan, in locomotive engines, an iron box, open to the front only, attached to the fire-box to receive the ashes from the fire. Ashpitel (W. H.), architect and en¬ gineer, born in 1776, was exten¬ sively employed in some very im¬ portant public works : his reputa¬ tion was of a dignified character; he died 20th April, 1852. His son, now in practice, is of equal merit. Aspect, in architecture, the front si¬ tuation of a building, or direction towards any point. Asphalt, native bitumen used with pitch as a substitute for pave¬ ment. Asphaltum, a bituminous substance, used for pavements and as a build¬ ing material. Asphaltum, called also Bitumen, Mineral Pitch, etc.; it is a resinous substance rendered brown by the action of the fire, natural or artifi¬ cial. The substances employed in painting under this name are the residua of the distillation of various resinous and bituminous matters in preparing their essential oils, and are all black and glossy like common pitch, which differs from them only in having, been less acted upon by fire, and in their being softer. Asphaltum is prin¬ cipally used in oil-painting: for which purpose it is first dissolved in oil of turpentine, by which it is fitted for glazing and shading. Its fine brown colour and perfect transparency are lures to its free use with many artists, notwith¬ standing the certain destruction which awaits the work on which it is much employed, owing to its disposition to contract and crack from changes of temperature and the atmosphere. Assay, to examine and prove metals. Assay balance, a very accurate ba¬ lance, used in determining- the c 2 27 ASSURANCE. ASS exact weights of very small bodies. Assaying, ascertaining the qualities of gold and silver with respect to their purity. Assemblage, in carpentry and joinery, framing, dovetailing, etc. Assemblage of the Orders, in archi¬ tecture, the placing of columns upon one another in the several ranges. Assembly room, the room or suite of rooms appropriated to the recep¬ tion of large parties, for balls, etc. Asser, a term used by Vitruvius for a rafter, carrying the tile of a roof. Asserts, small rafters immediately beneath the tiles of a roof. Assize Court, an edifice erected for the accommodation of the officials and the public at the sessions of the judges of the superior courts. Assula or Astula, chippings of blocks of stone, small marble slabs. Assurance, or Insurance, a contract to make good a loss. Assurance Companies, or Societies, afford protection to persons from the chances or hazards to which their property or interests may be exposed. Assurance on human life is a con¬ tract by which a certain amount of capital is secured at the expiration of a stipulated period, either by the payment of a specified sum at the time of effecting the assurance, or by the annual payment of a smaller amount, according to the age of a person whose life is as¬ sured. A person, with the view of secu¬ ring a certain sum of money to his family after his death, desires to effect an assurance, either for a determinate period, as one, three, five, seven, ten, or more years, or for the whole term of his life. In the first case, if the person whose life is assured, die before the expi¬ ration of the term specified in the policy, his inheritors receive the amount for which the assurance has been effected ; but, if the as¬ ASS sured live beyond that period, they receive nothing, and the assurer reaps the advantage of the contin¬ gency. In the latter case,—that is, by assurance for the whole term of life,—the inheritors are entitled to receive the amount named in the policy, upon proof of the death of the person whose life has been assured. To prevent the forfei¬ ture of the policy, it is in all cases essentially important that the con¬ ditions upon which it has been granted be strictly complied with. The calculation as to the amount of premium should be made ac¬ cording to mathematical expecta¬ tion,—that is, equitably as to both parties, allowing a fair rate of pro¬ fit to the party granting the assu¬ rance. If the terms for assuring £100 be required, for one year, the probability must depend on the age of the person whose life is pro¬ posed to be assured; and in equity the sum to be paid should be equal to the value of the expectation, multiplied by the probability of its being obtained. Should the age of the person be 40 years, the proba¬ bility of death in the course of the year will be, according to the ta¬ bles of mortality generally adopted, ; and this fraction, multi¬ plied by 100, gives the price of the assurance, namely, 174 nearly. The result, according to the tables of mortality used in France, is U89. This is the rate charged by the ‘ General Assurance Company ’ established at Brussels; but the ‘ Belgic and Strangers’ Union So¬ ciety’ charges at the rate of 1’87. Both societies adopt Dubillard’s table of mortality, which is depo¬ sited in the Bureau of Longitude in Paris. The profit to the assurer thus ap¬ pears to be reduced to the interest on the sum paid by the assured ; but persons in health being alone accepted, the chance of profit thereby becomes considerable. For a longer term than one year, the 28 ATT AC AMITE. ASS calculations are made on an esti¬ mate of the probable amount of interest derivable from the pre¬ mium paid by the assurer. Assynt marble, a white and greyish- white British marble, found in Sutherlandshire. Astel, in mining, a board or plank, an arch or ceiling of boards, over the men’s heads in a mine, to pro¬ tect them. Astragal, a small moulding, whose contour is circular, at the neck of the shafts of columns, next the apo¬ physes : it also occurs in the base of Ionic columns, and below the fasciae of the Corinthian epistylium. Astralish (mining), is that ore of gold which lies as yet in its first state or condition. Assyrian Architecture, of the period of Nineveh and the lower dynas¬ ties, see examples of style in the British Museum. Astronomy, a mixed mathematical science, which treats of the hea¬ venly bodies, their motions, pe¬ riods, eclipses, magnitudes, etc., and of the causes on which they depend: the knowledge of astro¬ nomy is essential in navigation and in measuring the earth’s sur¬ face : the diameter of this, the third planet in the system, is 7924 miles and 7 furlongs. Astylar, a term which expresses the absence of columns or pilasters, where they might otherwise be supposed to occur. Astyllen, in mining, a small ward or stoppage in an adit or mine, to pre¬ vent the free and full passage of water, by damming up. Asylum, in the Greek States, the tem¬ ples, altars, sacred groves, and statues of the gods; a place pro¬ vided for the protection of debtors and criminals who fled for refuge. Atacamite, prismatoidal green mala¬ chite, a native muriate of copper. Athanor, an ancient term for a metal furnace. Athenaeum, a school founded by the Emperor Hadrian, at Rome, for the ATM promotion of literary and scientific studies. Athwart-hawse, the situation of a ship when driven by the wind or tide across the fore-part of another. Atlantes, in architecture, male figures, used similarly to the female Carya¬ tides, in place of columns. Atmosphere, the invisible elastic fluid which surrounds the earth to an unknown (exact) height, and par¬ takes of all its motions ; the con¬ stituent parts are—air, water, car¬ bonic acid gas, and unknown bodies. The atmosphere is mea¬ sured by a column of mercury of 29'922 inches, which has been adopted in France as the mean height of the barometer at the surface of the sea. Atmospheric currents, in high lati¬ tudes, when undisturbed, are west¬ erly, particularly in the winter sea¬ son. If storms and gales revolve by a fixed law, and we are able, by studying these disturbing causes of the usual atmospheric currents, to distinguish revolving gales, it is likely that voyages may be short¬ ened. The indications of a revolv¬ ing gale are, a descending barome¬ ter, and a regularly veering wind. Atmospheric engine, an engine in which the steam is admitted only to the under side of the piston for the up-stroke ; it is then con¬ densed, and the top of the cylinder being open, the down-stroke is caused by the pressure of the at¬ mosphere. Marine engines on this principle have three cylinders con¬ nected to one crank-shaft, to ob¬ tain uniformity of motion. Atmospheric railway. The conclu¬ sions drawn by Mr. R. Stephenson are as follows : 1st, That the atmo¬ spheric system is not an economical mode of transmitting power, and inferior in this respect both to loco¬ motive engines and stationary en¬ gines with ropes. 2ndly, That it is not calculated practically to ac¬ quire and maintain higher veloci¬ ties than are comprised in the pre- 29 ATM ATMOSPHERE. ATT sent working of locomotive en¬ gines. 3rdly, That it would not, in the majority of instances, produce economy in the original construc¬ tion of railways, and in many would most materially augment their cost. 4thly, That on some short railways, where the traffic is large, admitting of trains of mo¬ derate weight, but requiring high velocities and frequent departures, and where the face of the country is such as to preclude the use of gradients suitable for locomotive engines, the atmospheric system would prove the most eligible. 5thly, That on short lines of rail¬ way, say four or five miles in length, in the vicinity of large towns, where frequent and rapid communication is required between the termini alone, the atmospheric system might be advantageously applied. 6thly, That on short lines, such as the Blackwall Rail¬ way, where the traffic is chiefly derived from intermediate points, requiring frequent stoppages be¬ tween the termini, the atmospheric system is inapplicable, being much inferior to the plan of disconnect¬ ing the carriages from a rope, for the accommodation of the inter¬ mediate traffic. 7thly, That on long lines of railway, the requisites of a large traffic cannot be attained by so inflexible a system as the atmospheric, in which the efficient operation of the whole depends so completely upon the perfect per¬ formance of each individual section of the machinery. Atmospheric vapour. Deluc proves the amount of force and vapour in a vacuum of any given dimensions is equal to its force and quantity in an equal volume of air at the same temperature, or that the tem¬ perature of the air will determine the force and quantity of vapour held in it. M. le Roi, however, first observed the temperature at which dew commences to be de¬ posited, as a rule of ascertaining the moisture of the atmosphere. Dr. Dalton investigated the force of vapour of every temperature, from zero to the boiling-point of water (Fahrenheit), and expressed this force by the weight of the mercurial column it could support in the tube of the barometer. Dalton and Le Roi find the clear point by pouring cold water into a glass, and marking the temperature at which it just ceasesto deposit dew on the sides of the glass in the open air. The temperature here observed is the point at which dew would begin to be formed. From this Dalton infers not only the force exerted by the vapour, but also its amount in a perpen¬ dicular column of the whole atmo¬ sphere, and likewise the force of evaporation at the time of obser¬ vation. Atomic iveights, or atoms, are the quantities in which the different objects of chemistry, simple or compound, combine with each other, referred to a common body, taken as unity. Atramentum, a dye made of soot mixed with burnt resin or pitch, used by the ancients, particularly by painters ; used also as a varnish. Atrium, a term applied by the Ro¬ mans to a particular part of a pri¬ vate house: the court or hall of a Greek or Roman house entered immediately from the fauces of the vestibulum. Attal, Attle, Adall, Addle, in mining, corrupt, impure off-casts, found in the working of mines. Attic base, the base of a column of upper and lower torus, a scotia, and fillets between them. Attic Order, a low order of architec¬ ture, used over a principal order, never with columns, but with antse or small pilasters. Attics should not be less than one- quarter nor more than one-third of the order they surmount: they are frequently decorated with small short pilasters, whose breadth 30 ATT AVILOR. AXI ought to be equal to the upper diameter of the column underneath them, and their projection usually not more than one-quarter of their breadth, Attic story, the upper story of a house when the ceiling is square with the sides, by which it is distin¬ guished from a common garret. Atticurgus, a term applied by Vitru¬ vius to the base of a column, which he describes as divided by a scotia or trochilus, with a fillet above and below, and beneath all a plinth. Attle, in mining, rubbish, deads, re¬ fuse, or stony matter. Attributes, in architecture, symbols given to figures, or disposed as ornaments on a building, to indi¬ cate a distinguished character. Attrition, the rubbing of bodies one against another, so as to destroy their surfaces. Auditorium, an apartment in monas¬ teries for the reception of strangers ; also, a place where the Roman ora¬ tors and poets recited their com¬ positions. Auger, a tool for boring large holes ; it consists of a wooden handle, ter¬ minated at the bottom with steel. Aula, an area or open place; in ancient Roman architecture, a court or hall. Auleolum, a small church or chapel. Aureola, a crown of glory, given by statuaries, etc., to saints, etc., to denote the victory they have ob¬ tained. Aurificina, a place for melting and refining gold, etc. Aurum, anciently, gold. Automaton, an apparently self-acting machine, constructed of weights, levers, pulleys, and springs, by means of which it continues in motion for a definite period. Autometer, an instrument to measure the quantity of moisture. Auxiliary, or cushion rafter, a term applied to the raking-piece of the truss in a green post. Avant mure, an outward wall. Avenue, a passage from one part of a building to another. Aviary, an apartment or building for the keeping of birds. Avilor (A. C. d’), architect, born in Paris in 1653. The companion with Desgodotz as travelling pupil to Rome in 1674 : both were cap¬ tured by Tunisian corsairs ; at Tunis Avilor designed and executed a mosque; was ransomed in 1676: published several works, principally of the styles of Louis XIV. and Louis XV. : died in 1700. Avolta, a place vaulted or arched over. A-weather, a term applied to the helm of a ship when it is put in the direction from which the wind blows. Awning, a covering of canvas over the the deck of a vessel, or over a boat, as shelter from the sun or rain. Axal section, a section through the axis of a body. Axes, the timbers of a roof which form two sides of a triangle, the tignum being the base: more gene¬ rally termed Principals. Axe, or broad axe, a tool used in hewing timber. Axiom, a self-evident truth. Axis, in architecture, an imaginary line through the centre of a column, etc., or its geometrical representa¬ tion : where different members are placed over each other, so that the same vertical line, on the elevation, j divides them equally, they are said to be on the same axis, although they may be on different planes: j thus, triglyphs and modillions are j so arranged, that one coincides with the axis or line of axis of each co- ; lumn : in like manner, the windows or other openings in the several j stories of a fa 9 ade must all be in | the same respective axis, whethei ; they are all of the same breadth i or not. Axis, in geometry, the straight line in a plane figure, about which it revolves to produce or generate a solid. Axis, in mechanics: the axis of a balance is the line upon which it moves or turns. 31 AXt AXLE. AZU Axis, in turning, an imaginary line passing longitudinally through the middle of the body to be turned, from one point to the other of the two cones, by which the work is suspended, or between the back centre and the centre of the collar of the puppet which supports the end of the mandril at the chuck. Axis of a circle or sphere, any line drawn through the centre, and ter- minated at the circumference on both sides. Axis of a cone, the line from the ver¬ tex to the centre of the base. Axis of a cylinder, the line from the centre of the one end to that of the other. Axis in peritrochio, a wheel and axle, one of the five mechanical powers, or simple machines; contrived chiefly for the raising of weights to a considerable height, as water from a well, etc. Axis of rotation, of any solid, the line about which the body really revolves when it is put in motion. Axle bearing, in locomotive engines, the gun-metal, or other metal bear¬ ing, under which the axle journal revolves: it is nicely fitted to the journal, and lubricated by a si¬ phon, to reduce, as far as practi¬ cable, the friction on the journal. Axle, in locomotive engines, journal, or neck, the part of the axle turned and polished for revolving in the axle-box bearing. Axle, leading, in locomotive engines, the front axle of the engine : eight- wheeled engines have two axles in front of the driving wheel axle, and they are often called leading axles. Axle, trailing, the last axle of the en¬ gine, usually placed under the foot¬ plate : in Stephenson’s and Cramp- ton’s patent engines, the driving wheel axle is the last axle. Axles, in locomotive engines, the iron shafts supporting the engine, and on which the wheels are fixed. Axles, driving wheel, in locomotive engines, with inside cylinders, this is a cranked axle; with outside cylinders, it is a straight axle; it is called the driving axle because the connecting-rods and eccentric- rods connect this axle to the pis¬ tons, slide-valves, and pumps, and by converting the rectilinear mo¬ tion of the piston into a rotatory one, it propels or drives the engine in the direction required. Axle-box, in locomotive engines, the box (usually cast iron) fitted up with a metal bearing in it, which rests upon the polished part of the axle. Axle-box cover, in locomotive en¬ gines, the plate of iron (usually lined with leather) fitted to the top of the axle-box to keep the oil clean, and also from shaking out by the motion of the engine. Axle-box siphon, in locomotive en¬ gines, the small tubes fitted into the top of the axle-box for feeding oil on to the axle journal as it re¬ volves : the oil is fed by a piece of cotton or worsted, having one end introduced into these pipes, and the other end lying down amongst the oil in the axle-box. Axle-guards, or horn-plates, in loco¬ motive engines, the parts of the frame in which the axle-box slides up and down, as acted upon by the springs. Axle-guard stays, in locomotive en¬ gines, the iron rods bolted to the frame and to all the ends of the axle-guards, to strengthen them. Azimuth compass, an instrument used at sea for finding the sun’s magne¬ tic azimuth. Azimuth dial, a dial of which the style or gnomon is perpendicular to the plane of the horizon Azote, called also Nitrogen, a gas which forms an important consti¬ tuent of atmospheric air, etc., but which, when breathed alone, de¬ stroys life. Azure, blue colour; in painting, a bright and florid tint of blue, equal in force to ultramarine with the addition of a little white. 32 BABEL. BAB Babel, Tower of, built by the poste¬ rity of Noah, after the Flood ; re¬ markable for its great height, and for the disappointment of the builders by the confusion of their language. It was erected in the plain of Shinar, upon the banks of the great river Euphrates, and near the place where the famous city of Ba¬ bylon subsequently stood. “ Let us build us a city and a tower whose top may reach unto heaven.”— Gen. xi. 4. “ The name of it is called Babel, because the Lord did there confound the language of all the earth, and from thence did the Lord scatter them abroad upon the face of all the earth.”— lb. xi. 9. Babylonian architecture takes its ap¬ pellation from the magnificence and extent of the public buildings of Babylon. This city was founded by Nimrod about 1665 years before Christ: its walls were fifty cubits thick and 200 in height, built of bricks made from the earth dug out of the ditch that surrounded the city. In the walls were 100 gates made of brass; the jambs and lintels were made of the same metal. Babylonian engine. An engine, to raise water from the Euphrates to supply the hanging gardens of Ba¬ bylon, was constructed and used in this the most ancient and splendid city of the early age, founded by the builders of Babel and enlarged by Nimrod, extended and beauti¬ fied by Semiramis. This engine greatly exceeded in the perpendi¬ cular the height to which the water was elevated by it. Extensive terraces were formed one above another to the top of the city walls; and to supply them with the necessary moisture, the engine was erected, of which no account is known at the present time. Bac, in navigation, a praam or ferry¬ boat. BAG B. Bac, in brewing, a cooler. Baccalaureus, an ecclesiastical appa¬ ritor or verger, who carries a staff of office. Bacca, a light-house, watch-tower, or beacon. Baccharis, ploughman’s spikenard* Baccio della Porta, called Fra Barto¬ lommeo, born 1469 ; of the Floren¬ tine school; he taught the use of the lay figure. Back, the back of a lode is the part of it nearest the surface ; the back of a level is that part of the lode extending above it to within a short distance of the level above. Back-board, in turning, that part of the lathe which is sustained by the four legs, and which sustains the pillars that support the puppet- bar : the back-board is only used in the best constructed lathes. Back centre screw, the screw for set¬ ting up the back centre of a lathe, to the work to be turned, after the puppet-head has been fixed. Backed, a sea phrase, to back an an¬ chor, to carry out a smaller one ahead of the one by which the ves¬ sel rides, to take off some of the strain. Background, in painting, is the space of ground behind the principal ob¬ jects of the picture. Back joint, applied by masons to a rebate such as that made on the inner side of the jamb of a chimney- piece to receive a slip. Back-links, the links in a parallel mo¬ tion which connect the air-pump rod to the beam. Back of a hip, in carpentry, is the upper edge of a rafter between two sides of a hipped roof, formed to an angle, so as to range with the raft¬ ers on each side of it. Back of a window, the board or wain¬ scoting between the sash-frames and the floor, uniting with the two elbows in the same plane with the shutters: when framed it is com- c 3 33 BAC BAKEHOUSE. BAL monly with single panels, with mouldings on the framing corre¬ sponding with the doors, shutters, etc., in the apartment in which it is fixed. Back-painting, the art of painting mezzotinto prints, on plate or crown glass, with oil colours. Backs, in carpentry, the principal rafters of a roof. Back-staff, an instrument nventedby Capt. Davis for a sea quadrant, so named because the back of the ob¬ server is turned towards the sun when using it. Back-stays, long ropes from the top¬ mast heads to both sides of the ship, where they are extended to the channels. Back-stay stool, a short piece of plank fitted for the security of the dead- eyes and chains for the backstays, though sometimes the channels are left long enough at the after end for the back-stays to be fitted thereto. Bac-maker, a cooper who makes liquor-bacs, etc. Baculometry, the art of measuring either accessible or inaccessible distances or lines, by the help of baculi, stqves, or rods. Baculus, a branch of hazel, used for the discovery of mines, springs, etc. Badigeon, in statuary, a mixture of plaster and freestone sifted and ground together, used by statuaries to repair defects in their work. Baguette, a small moulding, like the astragal: when enriched with foli¬ age, it is called a chaplet; when plain, a head. Bagnio, a bath. Bagpipe. To bagpipe the mizen is to lay it aback by bringing the sheet to the weather-mizen rig¬ ging- Bailey, an area of ground, a court, within the walls of a fortress; in modern acceptation, frequently applied to a prison. Baird (Mr.), in 1816, constructed a steamboat in St. Petersburg. Bakehouse, an apartment with an oven to bake bread. Baker’s central rule for the construc¬ tion of equations, is a method of constructing all equations not ex¬ ceeding the fourth degree. Bal, a term used in mining. Balance, Hydrostatic, an instrument which determines the specific gra¬ vity of fluids and solids by weigh¬ ing them in water. Balance, or equilibrium, in a picture, is when the forms of objects, the lights, shades, colours, and expres¬ sions, are happily adapted to each other, and no one figure or colour overpowers or obscures the rest. When a building is seen in one corner of a picture, it is frequently balanced by something in the other; even a large bird will produce the effect. Balance, one of the six simple powers in mechanics, chiefly used in de¬ termining the equality or differ¬ ence in heavy bodies, and conse¬ quently their masses or quantities of matter. Balances of various kinds are commonly used—as the common balance, the bent lever balance, the Roman balance, and the Swedish or Danish balance— for the adjustment of differences in weights, etc. Balance, in hydrostatics,'an instru¬ ment for determining the specific gravity of bodies. Balance {The) of a clock or watch, the part which, by the regularity of its motion, determines the beat or strike. Balance-gates, in hydraulic engineer¬ ing, may be described by referring to those made for the Compensation Reservoir of the East London Wa¬ ter-works. These gates were de¬ signed for the purpose of discharg¬ ing the body of water collected in the reservoh during the rise of the tide, in order to supply the mills lower down the river Lea, which might otherwise have been injured by the amount withdrawn from the river by the pumping-engines of 34 BAL BALL. BAL the Water Company. They differ in construction from common flood-gates, being made to work upon a vertical shaft or spindle as a centre, and having an equal sur¬ face of gate on each side of that centre; so that whatever pressure of water there may be on one side of the gate tending to force it open, there is as great a pressure on the opposite leaf to keep it shut. Balance-reef, a reef in a spanker or fore-aft mainsail, which runs from the outer head eaving diagonally to the tack; it is the closest reef, and makes the sail triangular. Balastre, the finest gold-cloth, manu¬ factured at Vienna. Balcony, a projection in the front of a house or other building, supported by consoles or columns, sometimes applied to the interiors of theatres, and for public convenience in large buildings. Balcony, the projecting gallery in the stern of large ships. Baldachin, a canopy supported by columns, and raised over altars, tombs, etc. Baldachino, in architecture, an open building supported by columns and covered with a canopy, frequently placed over an altar. Bale: to hale a boat is to throw water out of her. Balista, in practical geometry, the same as the geometrical cross, called the Jacob’s staff. Balistic pendulum, an instrument used for measuring the velocity of a cannon-ball, i.e. the force of gun¬ powder. It consists, in its simplest form, of a beam which can swing on a fixed axis at one end, while the ball strikes the other end; and the angle through which that end moves being known, the velocity of the cannon-ball may be com¬ puted. Balistics, the art of throwing missive weapons by means of an engine. Balistraria, a room in fortified build¬ ings, in which the crossbows were deposited. Balk, a great beam. Ball, any spherical body, either na¬ tural or artificial. Ballast, for ships, the materials for which are gravel, iron, or stone, or any heavy substance, to stow away in the hold, to bring a ship to a proper water-line when unladen, to counterbalance the effect of the wind on the masts, and to give sta¬ bility. Ball-cock, a hollow globe of metal at¬ tached to the end of a lever, which turns the stop-cock of a cistern- | pipe by floating on the surface of ; the water, thereby regulating the supply. j Ball-flower, an ornament like a ball, j placed in a circular flower, the pe- , tals of which form a cap round it; [ it belongs to the decorated style of the fourteenth century. Ball-lever, a lever of metal having a ball affixed at one end as a weight, which assists in closing again the plug or valve of a cistern after it has been pulled up to obtain a sup¬ ply of water. Ball of a pendulum, the weight at tne bottom of it; sometimes called the bob. Balister or Baluster, the lateral part of a scroll in the capital of the Ionic column; a little pillar-rail, such as are on the outside of cloisters. Ball and socket, an instrument made of brass, with a perpetual screw, so as to move horizontally, vertically, or obliquely : used for the managing of surveying and astronomical in- j struments. Ballon, is a round globe on the top of a pillar. Balloon or Baston, a mould at the base of a column called a Tore. i Balloon, a spheroidal hollow body, capable of floating in the air by means of its inflation with gas spe¬ cifically lighter than the air. Balloon, a globe placed on the top of a pillar or pediment, as an acroter or crowning. Balls, in electricity, are two pieces of 35 BAL BALUSTRADES. BAN cork or pith of elder-tree, nicely turned in a lathe to the size of a small pea, and suspended by means of delicate threads. Balk-staff, a quarter-staff. Ball-valves, the valves in the force- pumps of a locomotive engine : the balls are turned and ground truly spherical, so as to fit watertight into the valve-seats in every posi¬ tion. Balneac, in Greek, signifies a bath or bathing-vessel. Balteum, a band or girdle, according to Vitruvius : this word is used to denote the moulding on the bolsters or sides of the Ionic capital. Baltei, the bands in the flanks of Ionic pulvinated capitals. Balteum and balteus were generally used by the Romans to signify the belt by which the sword or quiver was suspended. Baluster, a small column or pillar used in a balustrade. Balusters are generally placed round the gallery in the stern and the quarter gallery of large ships. Balustrade, a series or row of balus¬ ters, joined by a rail, serving for a rest to the arms, or as a fence or enclosure to balconies, altars, stair¬ cases, etc. Balustrades, when intended for use, as against windows, on flights of steps, terraces, and the like, should not be more than three feet six inches, nor less than three feet in height. When used for ornament, as on the summit of a building, their height may be from two- thirds to four-fifths of the entabla¬ ture whereon they are employed ; and this proportion is to be taken exclusive of their zoccolo or plinth, so that from the proper point of sight the whole balustrade may be exposed to view. There are vari¬ ous species of balusters ; if single- bellied, the best way is to divide the total height of the space al¬ lotted for the balustrade into thir¬ teen equal parts,—the height of the baluster to be eight, of the base three, and of the cornice two of those parts; or divide the total height into fourteen parts, making the baluster eight, the base four, and the cornice two. If double- bellied, the height should be divi¬ ded into fourteen parts, two of which are to be given to the cor¬ nice, three to the base, and the re¬ mainder to the baluster. The distance between two balus¬ ters shofild not be more than half the diameter of the baluster in its thickest part, nor less than one- third of it; but on inclined planes the intervals should not be quite so wide. Bancalia, cushions or coverings for seats and benches. Band, in architecture, denotes any flat low member, or moulding, that is broad and not very deep. Banded column, a support which has its body interrupted at intervals by one or more broad projecting cinc¬ tures, etc. Bandle, an Irish measure of two fee in length. Bandlet, a small fillet, or flat mould¬ ing. Bandrol, a little flag or streamer affixed to the top of masts. Bank, a long piece of timber. Bank, a carpenter’s term for a piece of fir-wood unslit, from 4 to 10 inches square, and of any length. Bank: to double-bank an oar, is to have it pulled by two men. Banker {The), in bricklaying, a bench from 6 to 12 feet in length, used for preparing the bricks for gauged work. Banker, a cushion or covering for a seat. Banker hrowded, cushions embroid¬ ered. Banneret, anciently a knight made in the field, with a ceremony of cut¬ ting off the point of his standard and making it as if it were a banner. Banquet, the raised footway adjoin¬ ing to the parapet on the sides of a bridge. Banqueting house or room, a house 36 BAN BAR IRON. BAR or room where public feasts are given. Bantam-work, painted or carved work, resembling that of japan, only more gaudy. Baptaterium, a back-mill or fulling- mill. Baptistery, a place or edifice where baptism is performed. A basin, pool, or place for bathing. Bar, a barrier, gatehouse : in law, a place where counsellors plead. Bar, a bank or shoal at the entrance of a harbour. Bar of ground, in mining, any course of vein which runs across a lode, or different from those in its vicinity. Bar iron, long prismatic pieces of iron, being rectangular parallelopi- peds, prepared from pig iron, so as to be malleable, for the use of black¬ smiths for the method of joining bars. Barberry-wood is of small size, re¬ sembling alder, and is straight and tenacious. Barbacan, or Barbican, in the middle ages, a fort at the entrance of a bridge, or the outlet of a city; the part of a fortress where watch and ward was kept. Barbacan, a long narrow canal or passage for water in Wales, where buildings are liable to be overflowed, likewise to drain off water from a terrace. Bar-master, among miners, the per¬ son who keeps the gauge or dish for measuring the ore. Bar of the port, a billet thrust through the rings that serve to shut up the portholes of a ship. Barbarelli (Giorgio), of Castelfranco, known by the name of Giorgione, of the Venetian School of Painting. He died in 1511, at the age of 34. Barcella, a vessel containing incense. Barcon, a luggage-vessel used in the Mediterranean. Bardiglione, a blue variety of anhy¬ drite, cut and polished for orna¬ mental purposes. Bare poles, the condition of a ship when she has no sail set. Bari, the portion of a slate showing the gauge, and on which the water falls. Barge, a large double-banked boat used by the commander of a vessel in the navy. Barge-board, a front or facing to conceal the barge couples, laths, tiles, thatch, etc. Barge-boards (or, more properly, verge-boards), pendants, pinnacles, and brackets, being the chief decorations of houses in early domestic archi¬ tecture, should always be made of strong oak, and left to acquire by age a grey hue; and not of slight deal, painted, as is now the too frequent practice. Barge-couple, in architecture, a beam mortised into another, to strengthen the building. Barge-course, a part of the tiling or thatching of a roof, projecting over the gable, and filled up with boards, mortar, etc. Bargh-master, a surveyor of mines. Bargmote, a court held concerning the affairs of mines. Barium, a metal that exists in the sulphate and carbonate of barytes ; found in nature in great abund¬ ance. Barker’s mill, an hydraulic machine much in use. Barkery, a tan-house; also a sheep- cote. Bark hert, a seat in large gardens, a resting-place. Barmkyn, the rampart or outer forti¬ fication of a castle. Barn, a covered farm-building for laying up grain, hay, straw, etc. Barnacle, a shellfish often found on a vessel’s bottom. Barocci (Federigo), of the Roman school, in the style of Correggio, a style best calculated to reform an age which had neglected the true principles of art, particularly colour¬ ing and chiaroscuro. Barometer and Sympiesometer. The barometer is a measure for the weight of the atmosphere, or its pressure on the surface of the globe. 37 BAR BAROMETER. Bar It is well known that it is owing to the atmospheric pressure that water rises in a common pump after the air has been drawn from the barrel, but that the height to which it can be raised by this means is limited, and does not much exceeds 30 feet. A little more than 30 feet of water, therefore, balances the atmosphere. Mercury being about twelve times heavier than water, about 30 inches of mercury will also counterpoise the atmosphere. The principle of the barometer is simple. If a tube, about 3 feet long, closed at one end and open at the other, be filled with mercury, and, with the open end stopped by a finger, this tube be reversed, and placed upright in a cup partly filled wdth the same liquid, the mercury in the tube, in ordinary states of the weather, will descend to 30 inches, measured from the surface of the fluid in the cup, and not much lower. The mercury is sustained in the tube by the pres¬ sure of the atmosphere on the sur¬ face of the fluid in the cup. Such a tube and cup, so filled, would in fact be a barometer; and if a move- able index were added to it, this simple instrument would indicate the changes which take place in the atmospheric pressure. The Sympie- someter is a more delicate instru¬ ment for measuring the atmosphe¬ ric pressure; but it is also a more complicated one than the mercurial barometer, and it would be best un¬ derstood by inspection. The upper part of the tube contains hydrogen gas, which is elastic ; and the lower part, including the well, contains oil. By this compound construc¬ tion, whilst the length of the tube is less than that of the mercurial barometer, the index, or scale for measuring the pressure, is increased. Hydrogen gas being very sensibly affected by all changes of tempe¬ rature, the index, by which the at¬ mospheric pressure is read, requires to be set according to the actual temperature, before the atmospheric pressure can be read off. Since mercury expands by heat, a correction for temperature is also required for the mercurial barome¬ ter, when exact calculations are to be made; and for this reason ba¬ rometers usually have a thermome¬ ter attached to them, in order that the temperature may be read off, and recorded at the same time that the barometer is registered. The atmosphere is supposed to extend to about the height of 50 miles, and its density to diminish from the surface of the globe up¬ wards, in a geometrical ratio. Thus, when observations are made on land, above the level of the sea, a correction is required for altitude, since the weight of the atmosphere diminishes as we ascend. It is owing to this that we are enabled to determine the height of moun¬ tains by barometers, and that aero¬ nauts compute the altitude to which they ascend in balloons. The cause of the oscillations of the barometer in a gale of wind was first explained by the late Mr. Redfield, of New York.—A quan¬ tity of fluid in a cup, put in rapid circular motion, gives a represen¬ tation of the form of that portion of the atmosphere which is within the limits of a storm. A whirlwind which sets an extended portion of the atmosphere in a state of rapid revolution, diminishes the pressure over a corresponding portion of the earth’s surface, and most of all at the centre of the whirl, where the depth of the compressing column of air will he least. The principle of the barometer should be explained in all works on navigation, and in all schools where navigation is taught. The following is a table for the correction to be applied to the ob¬ served height of the mercury, to reduce it to the freezing point, at 32° Fahrenheit, or zero of the Cen¬ tigrade scale. 38 BAR BAROMETER. BAR Reduction of the English Barometer to the Freezing Point, or to 32° on Fahrenheit’s Scale.— Subtractive. (From Galbraith's Tables.) Temp. Part I.—For Mercury only. Part ii. —Mercury and Brass. c 0 Height of the Barom. in inches. Height of the Barom. in Inches. Fall. Cent. 28 In. 29 In. 30 In. 31 In. 28 In. 29 In. 30 In. 31 In. s O 32 °o-oo o-oooo 0-0000 0-0000 o-oooo 0-0088 0-0091 0-0094 0 0097 2 34 111 0-0056 0-0058 0-0060 0-0062 0-0138 00143 00148 00152 5 36 222 0-0112 0-0116 0-0120 0-0124 0-0188 0-0194 0‘0201 0 0208 7 38 3 33 0-0168 0-0174 0*0180 0-0186 0-0238 0-0246 0-0255 0 0263 9 40 4'44 0*0224 0-0232 0*0240 0-0248 0*0288 0-0298 0-0309 00319 11 42 555 0-0280 0-0290 0*0300 0-0310 0“0338 0*0350 0-0362 0-0374 12 44 666 0-0336 0*0348 0-0360 0*0372 0-0388 0 0402 0-0416 0 0430 14 46 777 0*0392 0-0406 0 0420 0*0434 0*0438 0-0454 0-0470 0 0485 16 48 8’88 0*0448 0-0464 0-0480 0-0496 0-0488 0-0506 0-0523 0 0541 17 50 1000 0-0504 0*0522 0-0540 0*0558 0*0538 0*0558 0-0577 0-0596 19 52 11-11 0*0559 0-0579 0-0599 0-0619 0*0583 00609 0-0630 0-0652 21 54 12-22 0-0615 0-0637 0-0659 0-0681 0-0638 0-0661 0-0684 0 0707 23 56 13*33 0-0671 0-0695 0-0719 0-0743 0-0688 0-0713 0-0738 0 0762 25 58 14*44 0-0727 0-0753 0-0779 0-0805 0-0738 0-0765 0 0791 0 0818 26 60 15-55 0-0783 0-0811 0-0839 0-0867 0-0788 0-0817 0-0845 0-0873 28 62 16-66 0*0838 0-0868 0*0898 0-0928 0-0838 0-0868 0-0898 0-0928 30 64 1777 0-0894 0-0926 0*0958 0-0990 0-0888 0-0920 0-0951 0 0983 32 66 18'88 0*0950 0-0984 0-1018 0*1051 0-0938 0-0971 0-1005 0-1039 34 68 20-00 01005 0-1041 0-1077 0-1113 0-0988 0-1023 0-1058 0-1094 36 70 21*11 0-1061 0-1099 0-1137 0-1175 0-1037 0-1075 0-1112 0-1149 38 72 22*22 0-1117 0-1156 0-1196 0-1256 0-1087 0-1126 0-1165 01204 40 74 2333 0-1172 0-1214 0-1256 0-1298 0-1137 01178 0*1218 01259 42 76 24-44 0-1228 0-1271 0*1315 0-1359 0-1187 0*1229 01272 01314 44 78 25*55 0*1283 0*1329 0*1375 0-1421 0-1237 0-1281 01325 01369 45 80 26-66 0-1339 0-1387 0-1434 0*1482 0-1286 0-1332 0-1378 01424 47 82 27-77 0-1394 0*1444 0-1494 0-1544 01336 0-1384 01432 01479 49 84 28-88 0-1450 0*1502 0-1553 0-1605 0-1386 0-1435 01485 01534 51 86 30-00 0-1505 0-1559 0-1613 0-1667 0-1435 0-1486 01538 0-1589 53 88 31-11 0-1561 01616 0-1672 0-1728 0-1485 0-1538 0-1501 0-1644 54 90 3222 0-1617 0-1674 0-1731 0-1790 0-1535 0*1589 01644 0-1699 56 P. P. for O O 0 _ 0 CO .0 2 1°. 6 2°. 0 0°. 4 0 00 0* 0 2 l°. 6 O O ’ CS Temp. F. + 12 24 35 47 59 10 21 31 42 52 for retaining the water of that river at a sufficient height to irrigate the summer crops. The dam consists of a curved quay, 4,500 feet in length; and two sluice-gates are placed at the head of the Delta, one on the Rosetta, the other on the Damietta branch, at a distance of half a league from each other. Barrel, in machinery, is a term ap¬ plied generally to anything hollow and cylindrical. Barrow, in mining, a heap of dead attle, rubbish, etc. Barrow, in salt-works, wicker cases almost in the shape of a sugar loaf, in which the salt is put to drain. Barrows, or tumuli, monuments of the greatest antiquity, raised as se- Baroscope, an instrument for finding out the variations of the air, or weather-glass. Barouche, a coach without a roof. Barozzi, otherwise Vignola, a dis¬ tinguished architect and painter, horn 1507, died in 1573. Barque, a three-masted vessel having her fore and main masts rigged like a ship’s, and her mizen-mast like the main-mast of a schooner, with no sail upon it but a spanker. Barra, in the middle ages, a tower or bar at one end of a bridge. Barracks, buildings for the lodgment of soldiers. Barrage, a mound or dyke to raise the waters of a river. One of the most remarkable works of- this kind is the Barrage of the Nile, 39 BASE-COURT. £>AJs BaR pulchres for the interment of the great. Barry (James), a painter, was born in Cork, October 1741, and died in the 65th year of his age. Bars, straight pieces of timber or metal that run across from one part of a machine to another. Bartholomew (Alfred),architect, born in 1801, published some excellent works for study and use, died in 1844 Bartisan, a wooden tower; a turret on the top of a bouse, castle, or church tower; a balcony or platform, within a parapet on the roof of any building; in architecture, bar- tisans are small overhanging turrets, which project from the angles on the top of a tower, or from the parapet or other parts of a building. Barton, the demesne lands of a manor, a manor house; the fields, a fold- yard, or outhouse. Barton house, a term used in the southern and western counties to express a farm-building, outhouse, and appurtenances. Bar wood, an African wood, in pieces four to five feet long. It is used as red dip-wood, also for violin bows, ramrods, and in turning. Barytes, a heavy mineral, found in copper-mines, and formerly named ‘ ponderous spar; ’ it has a caustic, alkaline taste, and is extremely poisonous. Basalt, a variety of trap-rock, hard and heavy, usually of a dark green or brownish-black colour, composed of augite and felspar, with some iron and olivine ; it frequently oc¬ curs in a columnar form. Basanite, a variety of schistose horn- stone, called also Lydian stone. Bascule bridge, a bridge to lift, to ac¬ commodate a passing for shipping. Base of a figure, in geometry, denotes the lowest part of its perimeter. Base of a conic section is a right line in the parabola and hyperbola formed by the common intersection of the cutting plane and the base of the cone. Base, in architecture, the lower part or member of a column, on which the shaft stands. Base-court, the outer or lower yard of a castle, appropriated to stables, offices, etc. Base-line, in perspective, the common section of a picture and the geo¬ metrical plane. Base-line, in surveying, a line, mea¬ sured with the greatest possible exactness, on which a series of tri¬ angles are constructed, in order to determine the position of objects and places. The measurement of degrees of the meridian, for the purpose of ascertaining the size of the earth, has been undertaken in various countries, with extreme accuracy. The arc measured by the French extended from Dun¬ kirk to the southernmost point of the Balearic Islands, including 120° 22' 14", having its centre halfway between the Equator and the North Pole. Another survey of this kind was performed on a part of the shore of Pennsylvania, which happens to be so straight and level as to admit of a line of more than 130milesbeingmeasured directly without triangulation. Very long lines have also been measured (trigonometrically) by order of the English Government, both at home and in India, the mean result of which makes the earth’s axis 7898 miles, 5 furlongs, 16 yards, and the diameter of the Equator 7924 miles 7 furlongs. Basement, the lower story or floor of a building; the story of a house below the level of the ground. Basements. As an alternative for employing orders upon orders, the ground-floor is made to assume the appearance of a basement, and the order that decorates the principal story placed thereupon: in such cases the basement should not be higher than the order it supports, nor lower than one-half the height of the order; but if a basement be introduced merely for the purpose 40 BAS BASILICA. BAS of raising the principal or ground- floor, it may be three, four, five, or six feet high, at pleasure. These basement stories are gene¬ rally in rock-worked or plain rus¬ tics ; and in no case should the height of a rustic course be less than one module of the order rest¬ ing on the basement, nor should it ever much exceed it: their joints, if square, ought not to be broader than one-eighth of the height of the rustic, or narrower than one- tenth, and their depth should equal their breadth ; if chamfered, the whole joint may be one-quarter to one-third the height of the rustic, the joint being always right-angled. When the basement is high, it is sometimes crowned with a cor¬ nice, but a plat-band is more com¬ monly used.— Gwilt. Basenet, a helmet. Base-plate, the foundation-plate of an engine. Basevi (George), an architect of con¬ siderable taste, born in 1794, acci¬ dentally killed in 1845. Basil, to grind the edge of a tool to an angle. Basilica, in the time of the Romans, a public hall or court of judicature. After the conversion of the Em¬ peror Constantine to Christianity, these edifices were converted into Christian churches. The Basilica of the Romans were the types from which the early Christian places of worship were taken ; and the ruins of these buildings were the chief materials used. In several instances the columns that divide the centre part of the church from the aisles have been taken from other edifices, either on account of the want of artists capable of executing any¬ thing equal to them, or the haste with which they were erected. The expedient that was adopted tends to show that proportion was not considered; some columns were reduced from their former height, and others mounted on pedestals, to suit the purposes to which they were applied. Besides this total disregard to proportion in the shafts of the columns, capitals and bases were applied without any consider¬ ation to their fitness. The heathen basilicae, generally situated in the forums, were of rectangular form, and divided into three or five parts by rows of columns parallel to the length of the building; another colonnade at the extremity crossed the former at right-angles, and in the middle of the end wall was a semicircular recess, in which was situated the tribune of the judge. These basilicae had likewise galle¬ ries over the aisles, in which com¬ mercial or other business was transacted; but in the Christian churches this was appropriated to the women, who (as in the Jewish synagogues) were not allowed to join with the men in the lower parts of the building. These gal¬ leries were omitted in the after basilicae, and one of the aisles was retained solely for their use. Six of the principal churches or basi¬ licae at Rome are attributed to the zeal of Constantine. The basilicae of St. John de Lateran, St. Peter, St. Laurentius, St. Paul, St. Agnes, and St. Stephen were built by him, besides the baptisterium that bears his name. The Christian Basilica may be sketched as follows :— 1. The Atrium, or court of en¬ trance, usually surrounded by a columned portico as in the heathen temples. This was an addition to the heathen basilica. 2. The Portico, in front of the building, called the Narthex or Scourge-—reserved for the catechu¬ mens and penitents, the former being confined to its precincts till baptism, the latter till ecclesiastical absolution. 3. In the interior, the central area, or nave, parted from its side- aisles by rows of columns—in the smaller churches single,in thelarger double ; the rows next the nave 41 BASINS. BAS almost invariably supported round arches instead of an unbroken archi¬ trave, and upon these arches rested the main walls of the building ; the walls were pierced with windows, under which often ran lines of mosaic; both nave and aisles were crowned with a wooden roof, and under that of the aisles Triforia, or galleries, as in their pagan proto¬ types, were sometimes provided for the women. 4. The Cancellum, Chancel , or Choir —the upper part of the nave, raised two or three steps, railed off or separated by a low wall, and appropriated to the sing¬ ers and inferior clergy ; within it, sometimes on the same side, more frequently on the opposite, stood the Ambones, or desks, that on the left for reading the Gospel, that on the right for the Epistle; the Paschal candlestick, emblematic of revealed religion, being fixed adja¬ cent to the former. The congre¬ gation stood on either side the can¬ cellum, the men to the right, the women to the left, as in the heathen basilicae. 5. The Triumphal Arch, intro¬ ducing from the central nave into the sanctuary, and thus figurative of the transition through death from the Church Militant on earth to the Church Triumphant in Heaven, respectively symbolized by the nave and sanctuary : subjects allusive to this triumph, the Sa¬ viour in glory or the Vision of the New Jerusalem of the Apocalypse, were usually represented on it in mosaic. 6 . The Transept, Presbytery, or Sanctuary, elevated by steps, in the centre of which stood the altar, originally uncovered, but after¬ wards surmounted by a ciborium or tabernacle supported by small pillars. 7. The Tribune or Ah sis, within which, overlooking the church, arose the throne of the bishop, flanked to the right and left by the BAS seats of his attendant clergy. The side-aisles were terminated by similar absides of smaller propor¬ tions. 8 . Lastly, the Crypt, beneath the sanctuary, generally half-sunk be¬ low the level of the earth, an open screen or grating admitting a sight of its interior from the nave, and of the Confession, the tomb or shrine containing the relics of the saint or martyr. The theory of a primitive church presumed it to be built over a catacomb. S. Agnes, S. Lorenzo, S. Martino, S. Prassede, and a few others at Rome actually are so; but as this could rarely be the case elsewhere, artificial catacombs or crypts were dug to represent them. At Rome, the Basilica of San Lorenzo, situated about a mile from the city on the Via Tiburtina. The Basilica of Santa Croce in Gierusalemme. The Basilica of San Giovanni in Laterano, the cathedral church of Rome, called the metropolitan church of the Christian world; it is also sometimes named the Basilica Constantiniana. The Basilica of San Sebastiano fuori le mura. The Basilica of Santa Maria Maggiore, which is also sometimes called the Basilica Laberiana. The Basilica of Santa Maria in Trastevere. The remaining Basilica is either that of San Pietro in Vaticano, or of San Paolo fuori le mura ; indeed both of them ought to be included in the number, as they have respec¬ tively the Porta Santa. Basilicula, a shrine, oratory, or ceno¬ taph. Basins and ewers. In early times, before the cleanly custom of using a fork was practised, the hands were frequently washed during dinner: a basin and ewer were handed for that purpose by an at¬ tendant. At the feast given by Henry VIII. to the French am- 42 BATH. BAS BAT bassadors, there were three ewry boards ; one for the king, another for the queen, and the third for the princes, etc. Basin, a concave piece of metal made use of by opticians to grind their convex glasses in. Basin, a reservatory of water; a canal; a pond ; a dock for repair¬ ing ships. Basset. The basset or outcrop means the emergence at the surface of the ditferent mineral strata from be¬ neath each other. Basset, or Outfall, applied to open¬ ings from or into mines to the sur¬ face. Bas-relief, or Basso-rilievo, low or flat relief, applied to sculpture con nected more or less with a plane surface, and of which the figures do not project in their full proportions. Bast, lime-tree bark made into ropes and mats. Bastard stucco, a three-coated plas¬ ter, the first generally roughing in or rendering; the second floating, as in trowelled stucco ; but the finishing coat contains a little hair besides the sand: it is not hand- floated, and the trowelling is done with less labour than in what is called trowelled stucco. Bastard-toothedfile , in smithing, that employed after the rubber. Bastard wheel, a flat bevel-wheel, or one which is a near approach to a spur-wheel. Bastida, in the twelfth century, a place of defence, a fortress. Bastille, a prison; a castle, tower, fortress, or any place of defence. Bastion, a rampart, bulwark, or earthen mound. Batardeau, a coffer-dam, or case of piling without a bottom, for build¬ ing the piers of a bridge. Batch, in mining, a certain quantity of ore sent to the surface by any pair of men. Bateau, a light boat, long in propor¬ tion to its breadth. Bateman light, a window in which the sides of the aperture are left to admit light, an upright, and the bottom horizontal. Bath, a receptacle for water, in which to plunge, wash, or bathe the body. Among the Romans, baths were erected magnificent both in style and purpose, and many of them of great architectural beauty. In later times the bath was always used by the Romans before they went to their supper. The rich generally had hot and cold baths in their own houses; and it was not till the time of Augustus that the baths assumed an air of grandeur and magnificence. The situation chosen for baths ought to be sheltered from the north and north-east. The caldaria and tepidaria should be made to receive their light from the west: or, should local circum¬ stances not admit of this dispo¬ sition, they may both be made to face the south, because the general time of bathing is from midday un¬ til sunset. One thing necessary to be observed is, that the caldaria of that division of the bath which is appropriated to the women should be contiguous to that exclusively used by the men, and have the same aspect; for then the cop¬ pers of both may be heated from the same furnace. Three brazen vessels are fixed over the furnace, which are severally called calda- rium, tepidarium, and frigidarium : they are so arranged, that whatever heated water is taken from the first, it is replaced by warm water from the second, the deficiency of which is supplied, in a similar man¬ ner, from the third. The concave coverings of the small tubes of both baths are likewise heated from the same furnace. The insulated stages of the caldaria are thus constructed: the floor is made inclining towards the furnace, so that if a ball were placed upon any part of it, it would not remain at rest, but take a direc¬ tion towards the mouth ; by which means' the flame will more easily pervade the interval between the 43 BAT BATTERY. BAY floors, which is paved with tiles a foot and a half square: upon the floor, earthen props, eight inches each way, are arranged at such in¬ tervals as to receive upon them square tiles two feet in length : the props are two feet in height; the tiles which form them are cemented with clay and hair mixed together. The square tiles which they support form the substratum of the pave¬ ment of the caldaria. Bath metal , a mixed metal, otherwise called Prince’s metal. Bath-stone, Bath oolite ; minute glo¬ bules, cemented together by yel¬ lowish earthy calcareous matter; it is much used in building, but is not a lasting material. It is soft when quarried, but hardens by exposure to the air. Ba/ifolium, a movable wooden tower used by besiegers in attacking a fortress. Batten , in carpentry, a scantling of wooden stuff, from two to four inches broad, and about one thick, principally used for wainscot, on which also are bradded, on the plain boards, also batten doors, those which resemble wainscot-doors, but are not so, for in wainscot-doors the panels are grooved in the fram¬ ing. Battens (nautical), thin strips of wood put around the hatches to keep the tarpaulin down; also put upon rigging to keep it from chafing. A large batten widened at the end, and put upon rigging, is called a Scotchman. Batter, to displace a portion of the iron of any bar or other piece by the blow of a hammer, so as to flatten or compress it inwardly, and spread it outwardly on all sides around the place of impact. Batter, a term applied to walls built out of the upright, or gently sloping inwards; wharf walls and retain¬ ing wails built to support embank¬ ments. Batter, the leaning back of the up¬ per part of the face of a wall, so as to make the plumb-line fall within the base. Battery, in electricity, a combination of coated surfaces of glass, com¬ monly jars, so connected that they may be charged at once and dis¬ charged by means of a common conductor. Battlement, an open or interrupted parapet on the roof of a building; a parapet with embrasures. Battory, a name given by the Hans Towns to their country-houses and warehouses in foreign coun¬ tries. Baugium, an outhouse or domestic office. Baulk, a piece of foreign fir or deal, from 8 to 16 inches square, being the trunk of a tree of that species of wood; generally brought to a square for the use of building. Bawdrick, a cord or thong for the clapper of a bell; a sword-belt; a jewel. Bawk, a cross-beam in the roof of a house which unites and supports the rafters ; a tie-beam. Bay, a division of a roof or vaulting of a building, consisting of the space between the beams or arches. A part of a window between the mullions is often called a bay or day. Bay, in plastering, the space between the skreeds, prepared for regulating and working the floating-rule. Bay of joists, the joisting between two binding joists, or between two girders when binding joists are not used. Bay of roofing, the small rafters and their supporting purlins between two principal rafters. Bay-salt, salt obtained by evaporating sea-water in shallow ponds by the heat of the sun ; it is of a dark grey colour, and contains iodine. Bay-tree, a native of Italy and Greece; it grows to the height of thirty feet, and its wood is aromatic. Bay-window, an oriel window; a win¬ dow jutting outwards; frequently called a bow-window. 44 BAY BEAMS. Bbn Bayeux tapestry, ordered to be work¬ ed by Matilda, the Queen of Wil¬ liam the Conqueror. Bazaar, a market-place. Beacon, a post or buoy placed over a shoal or bank, to warn vessels off: also a signal-mark on land ; a tower placed on an eminence, with a light to warn against the approach of danger. Beaconage, dues levied for the main¬ tenance of beacons. Bead, a small globular ornament used in ancient and modern architec¬ ture. Bead and Butt work, in carpentry, framing in which the panels are flush, having beads stuck or run upon the two edges, the grain of the wood being in the direction of them. Bead and quirk, a bead stuck on the edge of a piece of stuff, flush with its surface. Bead-butt and square-work, framing with bead and butt on one side; and square on the other: used in doors. Bead-plane, a moulding plane of a semi-cylindric contour, generally used in sticking a moulding of the same name on the edge or on the side close to the arris. Beak, the crooked end of a piece of iron, to hold anything fast. Beak, a small pendent fillet, forming a channel behind, to prevent water from running down the lower bed of the cornice. Beak-head, a small platform at the fore-part of the upper deck in large ships. Beak-iron, the conie part of the an¬ vil, with its base attached to the side, and its axis horizontal. Beaking-joint, the joint formed by the meeting of several heading joints in one continued line, which is sometimes the case in folded floors. Beam, a horizontal piece of iron or timber, used to resist a force or weight, as a tie-beam, where it acts as a string, or chain, by its ten¬ sion ; as a collar-beam, where it acts by compression; as a bres- summer, where it resists a trans¬ verse insisting weight. Beam, in steam-engines, a large lever turning upon a centre, and forming the medium of communication be¬ tween the piston-rod and the crank¬ shaft. Beam of an anchor, the straight part or shank to which the hooks are fastened. Beams. — Forms op Beams. In the construction of beams, it is ne¬ cessary that their form should be such that they will be equally strong throughout; or, in other words, that they will offer an equal resistance to fracture in all their parts, and will, therefore, be equally liable to break at one part of their length as at another. If a beam be fixed at one end and loaded at the other, and the breadth uniform throughout its length, then, that the beam may be equally strong throughout, its form must be that of a parabola. This form is generally used in the beams of steam-engines; and in double-acting steam-engines the beam is strained sometimes from one side, and sometimes from the other; therefore, both the sides should be of the same form. Mr. Emerson gives the load that may be safely borne by a square inch rod of each of the following : lbs. avoird. Iron rod an inch square 1 will bear Brass . . . Hempen rope Ivory . . . Oak, box, yew, plum tree . . . Elm, ash, beech Walnut, plum Red fir, holly, elder plane, crab . . Cherry, hazel . . Alder, asp, birch, wil low. Lead. Freestone.... 35.600 19.600 15,700 - 7,850 6,070 5,360 5,000 5,000 4,760 ► 4,290 430 914 He also gives the following prac- 45 BEAMS. BEA BEA tical rule, viz. That a cylinder, the diameter of which is d inches, loaded to one-fourth of its absolute strength, will carry as follows :— cwt. Iron.135 x d 2 Good rope . . . 22 x ^ Oak.14 x d 2 Fir. 9 x d 2 He also adds, that a cylindric rod of good clean fir, of an inch cir¬ cumference, drawn in length, will bear at its extremity 400 lbs.; and that a spar of fir, 2 inthes diameter, will hear about 7 tons, but not more. A rod of good iron, of an inch circumference, will bear nearly 3 tons weight. A good hempen rope, of an inch circumference, will bear 1000 lbs. being at its extremity. Mr. Barlow gives the following table as a mean derived from his experiments on the strength of direct cohesion on a square inch of the following:— lbs. Box, about . . . . 20,000 Ash . . . . . . 17,000 Teak . . . . . . 15,000 Fir .... . . . 12,000 Beech . . . . . . 11,500 Oak . . . . . . 10,000 Pear . . . . . . 9,800 Mahogany . . . . 8,000 Transverse Strength of Beams, etc. — The transverse strength of rectangular beams, or the resistance which they offer to fracture, is as the breadth and square of the depth : therefore, if two rectangular beams have the same depth, their strengths are to each other as their breadths; but if their breadths are the same, then their strengths are to each other as the squares of their depths. The transverse strengths of square beams are as the cubes of the breadths or depths. Also, in cylindrical beams, the transverse strengths are as the cubes of the diameters. Thus, if a beam which is one foot broad and one foot deep, support a given weight, then a beam of the same depth, and two feet broad, will support double the weight. But if a beam be one foot broad and two feet deep, it will support four times as much as a beam one foot broad and one foot deep. If a beam one foot square sup¬ port a given weight, then a beam two feet square will support eight times as much. Also, a cylinder of two inches in diameter will sup¬ port eight times as much as a cy¬ linder one inch in diameter. The following table of data is extracted from tables in Barlow’s Essay:— Teak.2,462 English oak .... 1,672 Canadian do.1,766 Dautzic do.1,457 Adriatic do.1,383 Ash.2,026 Beech.1,556 Elm.1,013 Pitch pine.1,632 Red pine.1,341 New England fir . . . 1,102 Riga fir.1,108 Mar Forest fir. . . . 1,262 Larch.1,127 Beam-ends. A ship is said to be on her beam-ends when she inclines very much on one side, so that her beams approach to a vertical posi¬ tion. j Beam-engine, generally a land en¬ gine, which has the top of the pis¬ ton-rod connected to one end of a lever or beam ; by a contrivance called a parallel motion, the beam vibrates upon a central axis, and communicates the motion of the piston to the crank by means of a connecting-rod attached to the other end of the beam, and also gives motion to the various parts. Beam filling, the brickwork, or ma¬ sonry, brought up from the level of the under to the upper sides of beams. Beam gudgeons, the bearings on the 46 BEA BEDS. BED centre of the beam, or the central pivot upon which it vibrates. Beam of a balance, the horizontal piece of iron from the ends of which the scales are suspended. Beams , in naval architecture, strong thick pieces of timber stretching across the ship from side to side, to support the decks: they are sus¬ tained at each end by thick planks in the ship’s side, called clamps, upon which they rest. Bearer, anything used by way of sup¬ port to another weight. Bearer, in turning, that part of the lathe which supports the puppets. Bearing, the distance that a beam or rafter is suspended in the clear: thus, if a piece of timber rests upon two opposite walls, the span of the void is called the bearing, and not the whole length of the timber. Bearing, that part of a shaft or spindle which is in contact with the supports. Bearing, a word used in describing a plaster figure copied from the antique. It is generally said, if the drawing or outline of a figure has not the same bearings or angles of inclination as the original pos- esses, that it is out in all its bearings. Bearing, in heraldry, the figures on a coat of arms; a coat of arms in general. Bearing, the direction of an object from the person looking. In ship¬ ping,the bearings of a vessel are the widest part of her below the plank- sheer ; that part of her hull which is on the water-line when she is at anchor and in her proper trim. Beat away, in mining, to excavate ; usually applied to hard ground. Beating, in navigation, the operation of making progress at sea against the wind. Beaufet, a cupboard or niche. Beaufrey, a beam or joist. Beau ideal, in painting, that beauty which is freed from the deformity and the peculiarity found in nature in all individuals of a species. Beauty, in architecture, consists of the following qualities : magnitude and strength, order and harmony, richness and simplicity; Construc¬ tion, in which the chief requisites are magnitude and strength, order and harmony ; Decoration, whose requisites are richness or simplicity, according to the nature of the com¬ position. Beazley (Sami.), an architect of re¬ putation, particularly in the con¬ struction of theatres; he also executed with success many other buildings. Born 1786; died in 1851. Becalm, to intercept the wind by al¬ ternate tacks. Beck, a little river or brook. Beck, an English weight containing sixteen English pounds, or two gallons. Becket, a piece of rope, placed so as to confine a spar or another rope; a handle made of rope in the form of a circle. Bed of a brick, the horizontal sur¬ faces as disposed in a wall. Bed, a term used in masonry to de¬ scribe the direction in which the natural strata in stones lie ; it is also applied to the top and bottom surface of stones when worked for building. Bed, in mining, a seam or horizontal vein of ore. Beds, of stonework, are the parallel surfaces which intersect the face of the work in lines parallel to the horizon. Beds and Bedding. Feather - beds, bolsters, and pillows, filled with feathers and down, with mattresses and every other comfort of this kind, seem to have been as well known to, and enjoyed by, the su¬ perior orders of society three cen¬ turies ago, as they are now. Di¬ rections are, however, mentioned as having been given in the reign of Henry VIII. “ to examine every night the straw of the king’s bed, that no daggers might be con¬ cealed.” . 47 BED BEECHWOOD. BE* Beds (Trussing ) were beds which packed into chests, for travelling; and, considering the frequent re¬ movals, these must have been the most convenient kind. John of Ghent seems to have always slept in such beds, as by his will it ap¬ pears that he demised to his wife all the beds made for his body, “calledin England trussing-beds and the “ best chambers ” of both Master Fermor and Sir Adrian Fos- kewe had trussing-beds. Bed-chambers: in Tudor times the furniture of these apartments, in great houses, was of the same gor¬ geous character as that in the chief rooms; and the paraphernalia of an ancient dressing-table yielded only in the splendour and costliness of plate, to the cupboard of the great chamber, or the altar of the chapel. Like the hall, the state bed-cham¬ ber had a high place, on which were placed the ‘standingbed’ and the ‘truckle-bedon the former lay the lord, and on the latter his at¬ tendant. Beddern, a refectory. Bedding-stone, used in bricklaying, a straight piece of marble : its use is to try the rubbed side of the brick; first, to square, to prove whether the surface of the brick be straight; secondly, to fit it upon the leading skewback, or leading end of the arch. Bed-moiddings. This may be under¬ stood as a collective term for all the mouldings beneath the corona or principal projecting member of a cornice, which, without bed- mouldings, would appear too much like a mere shelf. Bed-plate, the foundation-plate of a marine or a direct-action engine. Bedsteads: in Tudor times the posts, head-boards, and canopies or sper- vers of bedsteads were curiously wrought and carved in oak, walnut, box, and other woods, and variously painted and gilt. Ginger-colour, hatched with gold, was a favou¬ rite style, but purple and crimson were also used in their decoration. Bede, among miners, a kind of pick¬ axe used for separating the ores from the rocks in which they lie. Bedesmen, almsmen who prayed for their benefactors and founders. Bede-house, an almshouse or hospi¬ tal. Beech, a species of timber very much used by artificers : while young, it possesses great toughness, and is of a white colour: the cohesive strength of this timber requires 12,225 lbs. weight to tear asunder a piece one square inch in thick¬ ness. Beech-wood, common in Buckingham¬ shire and Sussex as the best; about fifty feet high and thirty inches in diameter; white, brown, and black colour : it is used for piles in wet foundations ; is used also, for its uniform texture and closeness, in in-door works, as the frames of machines, bedsteads, and furniture; also for planes, tools, lathe-chucks, keys, cogs of machinery, brushes, bandies, etc. Beef-wood, red-coloured wood, gene¬ rally applied to Botany Bay oak. Beer-drawing machines are contriv¬ ances by means of which beer is drawn from a barrel or cask. Beer or Bere stone, composed chiefly of carbonate of lime, friable and with partial indurations. It is ex¬ tensively quarried at Bere, or Beer, in Devon. Bees, pieces of plank bolted to the outer end of the bowsprit, to score the fore-topmast stays through. Beetle, or Maul, a large mallet to knock the corners of framed work, and to set it in its proper position : the handle is about three feet in length. Beetle, or Boytle, a wooden instru¬ ment or hammer for driving piles, stakes, wedges, etc. Before the beam, in naval architec¬ ture, is an arc of the horizon com¬ prehended between a line which crosses a ship’s length at right an¬ gles, and some object at a distance 48 BELL. BEH BEN before it; or between the line of the beam, and that point of the compass which she stems. Behr (Geo. Hen.), published in 1732 a work on Strasburg Cathedral. ! Belace, Belage, or to Belay, to fasten any running rope when it is haled, that it cannot run forth again ; to mend a rope by laying one end over another. Belandre, in navigation, a sort of Nor¬ man vessel. Belay, to make a rope fast by turns round a pin or coil, without hitch¬ ing or seizing it. Belfry, that part of the lower of a church which contains bells. Bell (Henry), late of Glasgow, who, in 1812, tried Symington’s plan for navigating by propulsion a steam- vessel on the Clyde. The vessel (‘The Comet’) was 25 tons bur¬ den, 40 feet long and 10 feet beam, with a steam-engine of four-horse power, which succeeded. Bell, a metallic instrument rung in the belfry of a church for the attend¬ ance of divine worship, and upon occasions of rejoicing; composed of three parts of copper and one of tin, called bell-metal. Bell: the body of a Corinthian or Composite capital, supposing the foliage stripped off, is called the bell; the same is applied also to the early English and other capitals in Gothic architecture which in any degree partake of this form. Bell-cage, a timber frame, also called Belfry, carrying one or more large bells. Bell-canopy, a canopy containing a bell in harness. Bell-chamber, the room containing one or more large bells in harness. Bell-cot , a structure presenting the appearance of a steeple. Bell-crank, a bent lever, used for changing a vertical into a horizon¬ tal motion. Bell-gable, a term applied to the gable of a religious edifice, having a plain or ornamental niche for the recep¬ tion of one or more bells. Bell-trap, a contrivance, usually air¬ tight, consisting of an inverted cup, the edges of which dip into a trench, gutter, or canal holding water, and formed at the top of a pipe, for the purpose of prevent¬ ing foul smells ascending from the drain into the air. Belloivs, the instrument for blowing a fire, with an internal cavity so contrived as to be of greater or less capacity by reciprocating motion, and to draw in air at one place while the capacity is upon the increase, and discharge it by another while upon the decrease. The bellows are placed behind the forge with a pipe, and are worked by means of a lever, called a rocket. Steam machinery is now much used for blowing furnaces. Bellows, or water blowing-engine, is a machine in w'hich the stream of air is supplied by the flowing of water. Belly, the hollow part of a compass timber, the round part of which is called the back. Belt, in building, a string-course and blocking-course ; a course of stones projecting from a wall, either moulded, plain, fluted, or enriched. Belvedere, a turret, lantern, or cupola, raised above the roof of a building. It is sometimes applied in Italy to open galleries or corridors. Belzoni (G.), an explorer of Egyptian antiquities; died in 1823. Bema, an ambo, or reading-desk; a raised structure for the seat or throne of a bishop. Bema, the sanctuary, presbytery, or chancel of a church. Bema, in Greek, the platform from which the orators spoke in the Athenaeum. Bema, a bishop’s throne. Ben-alive, a Cornish term in mining. Bench, for carpenters and joiners to do their work on, usually 10 or 12 feet in length, and about 2^ feet in width. Bench-mark, in surveying, is applied to a mark showing the starting- point in levelling along a line, and 49 D BEN BEVEL. BEV to similar marks affixed at conve¬ nient distances to substantial or permanent objects, to show the ex¬ act points upon which the levelling staffs were placed when the various levels were read, thus facilitating reference and correction. Bench-planes. The jack-plane, the trying-plane, the long-plane, the jointer, and the smoothing-plane, are called bench-planes. Bench-table , a low stone seat round the interior of the walls of many churches. Bend, in mining, indurated clay; a name given by miners to any indu¬ rated argillaceous substance. Bend, the form of the ship from the keel to the top of the side, as the midship bend, etc. Bends, the strongest parts of a ves¬ sel’s side, to which the beams, knees, and futtocks are bolted. Bending-strakes, two strakes wrought near the coverings of the deck, worked all fore and aft, about one inch or one inch and a half thicker than the rest of the deck, and let down between the beams and ledges so that the upper side is even with the rest. Bending of timber. The process of bending wood to any required curve depends on the property of heat, as its pressure increases the elasticity of the wood. Benefice, a church endowed with a revenue for the performance of divine service. Benetier, a vessel to contain holy water; a font, or piscina. Ben-heyl, in Cornish mining, rich in tin. Benticlc-shrouds, formerly used, and extending from the futtock-staves to the opposite channels of a vessel. Benzine, the bicarburet of hydrogen, procured by heating benzoic acid with lime. Bergamo, a coarse tapestry. Bergmote, a court held on a hill, for tlie decision of controversies among miners. Berne machine, for rooting up trees ; the invention of Peter Sommer, of Berne. Berth, the place where a vessel lies; the place in which a man sleeps. Berth, convenient sea-room to moor a ship. Bertying a ship, the rising up of the ship’s sides. Beryl, a pellucid gum, of a bluish- green colour, found in the East Indies, Peru, etc.; used by artists. Bethel’s patent for preserving wood. This patent was taken out in 1838, and consists in thoroughly impregnating the wood with oil of tar containing creosote and a crude solution of acetate of iron. Betty, in mechanics, an instrument to break open doors. Beton, the French name for concrete : beton is composed by first mixing the proper proportions of lime and sand, either by hand or by a pug- mill, in the same manner as for ordinary mortar. Bevel, any angle except one of 90 de¬ grees. Bevel, in bricklaying, is for drawing the soffit-line on the face of the bricks. Bevel, in joinery : one side is said to be bevelled with respect to another, when the angle formed by these two sides is greater or less than a right angle. Bevel gear, in mechanics, denotes a species of wheel-work where the axis or shaft of the leader or driver forms an angle with the axis or shaft of the follower or the driven. In practice it is requisite to have finite and sensible teeth in bevel gear: these are made similarly to those of spur gear, except that in the latter they are parallel, while in bevel gear they diminish in length and thick¬ ness in approaching the apex of the cone: the teeth are of any breadth, according to the strength required. Bevel gearing is stronger, works smoother, and has superseded the face-wheel and trundle. Bevelling, in sliip-building, the wind¬ ing of a timber, etc., agreeably to 50 BEY BIMEDIAL LINE. BIR directions given from the mould- loft. Bevel-wheel, a wheel having teeth formed so as to work at an angle either greater or less than half a right angle. Bibbs, in ship-building, pieces of tim¬ ber bolted to the hounds of a mast, to support the trestle-trees. Bibliotheca, in Greek, the place, apart¬ ment, or building where books were kept. Bicarbide of hydrogen. This gas is known by the names of light car- buretted hydrogen, marsh-gas, fire¬ damp, and gas of the acetates. It is discharged from fissures in coal in large quantities, and from the bottoms of the pools in which there is vegetable matter. Bice, a blue colour used in painting, prepared from the Lapis Armenius. Bice, or Bise, in painting, a pale blue colour, procured by the reduction of salt to a fine powder. Bicellum, the dwelling of a tradesman, having under it two vaults, for the reception of merchandise. Bichoca, a turret or watch-tower. Bier-balk, the church-road for burials. Bifrons, in sculpture, double-fronted or faced, usually applied to Janus. Bigelf an arch or chamber. Bigg, to build. Bigger , a builder. Bight, the double part of a rope when it is folded, in contradistinction from the ends. Bilander, a small vessel with two masts, used chiefly in the canals of the Low Countries. Bilboes, large bars or bolts of iron, with shackles sliding on them, used for criminals. Bilage, the breadth of a floor of a ship when she lies aground. Bilge-pump, that which is applied to the side of a ship, to exhaust or pump out the bilge-water. Bilection-mouldings, those surround¬ ing the panels, and projecting before the face of a door, gate, etc. Bilge, that part of the floor of a ship which approaches nearer to a hori¬ zontal than to a perpendicular di¬ rection. Bilge-pump, the forcing-pump worked by a marine engine, to discharge the bilge-water from tlie vessel. Bilye-pump rod, the plunger-rod, or rod connecting the piston of the bilge-pump to one of the side- levers. Bill, the point at the extremity of the fluke of an anchor. Billet-moulding, an ornament used in string-courses and the archivolts of windows and doors. Billiard-room. The apartment pre¬ pared for the reception of a billiard table, and therefore requiring to be of specific dimensions. Billion, in numbers, the sum of a mil¬ lion of millions. Bills, the ends of compass or knee- timber. Bimedial line, in geometry, the sum of two medials. When medial lines, equal only in power and containing a rational rectangle, are compound¬ ed, the whole will be irrational with respect to either of the two; this is called a first bimedial line ; but if two medial lines, commen¬ surable only in power, and con¬ taining a medial rectangle, be com¬ pounded, the whole will be irra¬ tional, and is then called a second bimedial line. Binary, in arithmetic, double. Binder, one who undertakes to keep a mine open. Binding-joists, those beams in a floor which support transversely the bridgings above and the ceiling- joists below. Bindings, the iron wrought round the dead-eyes. Binnacle, a box near the helm, con¬ taining the compass. Binocular telescope, one to which both eyes may be applied. Bins, for wine, open subdivisions in a cellar for the reception of bottles. Birch-wood, a forest tree, common to Europe and North America; an excellent wood for turning, being d 2 51 BITUMEN. BIR of light colour, compact, and easily worked. Bird (Edward), painter, born at Wol¬ verhampton, April 1772, died No¬ vember 1819. Bird's-eyeperspective is of two kinds, angular and parallel: it is used in the drawings of extensive buildings having spacious courts and gardens, as palaces, colleges, asylums, etc. The observer is supposed to be on an eminence, and looking down on the building, as from a steeple or mountain. Bird's-mouth, in carpentry, an interior angle or notch cut in the end of a piece of timber for its reception on the edge of a pole or plate. It sig¬ nifies also the internal angle of a polygon. Bireme, a vessel with two hanks or tiers of oars. Birhomboidal, having a surface of twelve rhombic faces, which, being taken six and six, and prolonged till they intercept each other, would form two different rhombs. Birthing, the working a top side, bulk¬ heads, etc. Bisection, in geometry, the division of any quantity into two equal parts. Bishops, prelates holding baronies of the King or of the Pope, and exer¬ cising ecclesiastical] urisdiction over a certain extent of territory, called their diocese. Bismuth. This metal is found native, crystallized in cakes, which gene¬ rally contain small quantities of silver; it is also combined with oxygen, arsenic, and sulphur. Bispia, abishopric or episcopal palace. Bissextile, or leap-year, a year con¬ sisting of 366 days, happening once every four years, by the addition of a day in the month of February, to recover the six hours which the sun spends in his course each year, beyond the 365 days usually allow¬ ed for it. Bistre, a brown pigment, extracted hv watery solution from the soot of wood fires, when it retains a strong pyroligneous scent. It is BLA of a wax-like texture, and of a ci¬ trine-brown colour, perfectly dura¬ ble. It has been much used as a water-colour, particularly by the old masters, in tinting drawings and shading sketches, previously to Indian ink coming into general use for such purposes. In oil, it dries . with the greatest difficulty. Bisturres, small towers placed at in¬ tervals in the walls of a fortress, forming a barbican. Bit, an instrument for boring holes in wood, etc. Bitter (a sea term), a turn of a cable about the timbers called bitts, when the ship lies at anchor. When a ship is stopped by the cable, she is said to he brought up by a hitter. Bitternut-wood, a native of America, is a large timber wood, measuring 30 inches when squared ; plain and soft in the grain, like walnut. Bitts, in ship-building, perpendicular pieces of timber going through the deck, placed to secure anything to. The cables are fastened to them, if there is no windlass. There are also bitts to secure the windlass, and each side of the heel of the bowsprit. Bitumen, a name for a number of inflammable mineral substances, known under the . names of naph¬ tha, mineral tar, mineral pitch, sea-wax, asphalte, elastic bitumen, or mineral caoutchouc, jet, mineral coal, etc. Bituminous cement, a factitious sub¬ stance, used for pavements, for roofs, and other useful purposes. Bituminous limestone, a limestone of a lamellar structure. Black, the last and the lowest in the series or scale of descending co¬ lours ; the opposite extreme from white; the maximum of colour. To be perfect, it must be neutral with respect to colours individually, and absolutely transparent, or desti¬ tute of reflective power in regard to light, its use in painting being to represent shade or depth, of which it is the element in a picture 52 BLA BLAST. BLA and in colours, as white is of light. Black-band iron-stone, discovered by Mr. David Mushet, in 1801, while engaged in the erection of the Calder Iron-works. Great prejudice was excited against him by the iron-masters, in presuming to class the wild coals of the country with iron-stones lit and proper for the blast furnace; yet that discovery has elevated Scotland to a consi¬ derable rank amongst the iron¬ making nations of Europe, and pro¬ duces an annual average income of £16,500 to Sir W. Alexander, Bart. Black Botany Bay wood is the hardest and most wasteful of all woods; some of the finest, however, if well selected, exceeds all woods for ec¬ centric turning. Black chalk is an indurated black clay, of the texture of white chalk: its principal use is for cutting into the crayons which are employed in sketching and drawing. Black dye : the ingredients of black dye are logwood, Aleppo galls, ver¬ digris, and sulphate of iron, or green vitriol. Black iron, malleable iron, in contra¬ distinction to that which is tinned, called white iron. Black Jack, in mining, blende. Black lead, plumbago, or graphite, is a native carburet of iron, or oxide of carbon, found principally at Bor- rodale in Cumberland; consumed in large quantities in the formation of crayons and black-lead pencils for writing, sketching, designing, and drawing. Black marble. The marble called in commerce Nero Antico, and Egyp¬ tian black, is the most beautiful black marble without any ad¬ mixture of other colours. In Eng¬ land the chief quarries of uniform colours and texture are at Ashford, Bakewell, Derby, etc. Black ochre, a variety of the mine¬ ral black, combined with iron and alluvial clay. Black tin, tin ore when dressed, stamp¬ ed, and washed, ready for melting. Black wadd, one of the ores of man¬ ganese, used as a drying ingredient in paints. Blade, in joinery, is expressive of any part of a tool that is broad and thin, as the blade of an axe, of an adze, of a chisel, of a square : the blade of a saw is more frequently called the plate. Blades, the principal rafters or breaks of a roof. Blanc d’argent, or silver-white. This is a false appellation for a white lead, called also French white. It is first produced in the form of drops, is exquisitely white, but is of less body then flake white, and has all the properties of the best white leads; but, being liable to the same changes, is unfit for gene¬ ral use as a water-colour, though good in oil or varnish. Blake (William), a poor but meritori¬ ous artist, was born in London, in November 1757. The Canterbury Pilgrimage was designed by him. His first work was, however, the Songs of Innocence ; his next, the Gates of Paradise. Poverty-stricken as he was, his cheerfulness never forsook him ; he uttered no com¬ plaint, he contracted no debt, and continued to the last manly and in¬ dependent. Blast, the air introduced into a fur¬ nace. Blasting of stone, from rocks and beds of stone, for the purpose of quarrying and shaping stones to be used for building purposes: the ordinary implements used are the jumper or cutting-tool, the ham¬ mer, and scraper. For the process and its effect, see Sir John Bur- govne’s Rudimentary Volume on Blasting, etc. Blast-pipe, the waste steam-pipe of an engine, but more particularly applied to locomotive engines : in the latter it leads from the exhaust passages of the cylinders into the chimney, and is of great use for forming the draught through the fire-tubes, as each jet of steam 53 BLENDING. BLE emitted creates a partial vacuum in the chimney, which is immediately filled by a current of air rushing through the fire-grate. Bleaching , an art divided into branches, bleaching of vegetable and animal substances requiring different pro¬ cesses for whitening them. Blend, a mineral substance resem¬ bling lead. Blende, in mining, an ore of zinc, composed of iron, zinc, sulphur, si- lex, and water: on being scratched, it emits a phosphoric light. Blending and melting, in colouring or painting, are synonymous terms. They imply the method of laying different tints on buildings, trees, etc., so that they may mingle to¬ gether while wet, and render it impossible to discover where one colour begins and another ends. A variety of tints of nearly the same tone, employed on the same object and on the same part, gives a richness and mellowness to the effect; while the outline, insensibly melting into the background, and artfully disappearing, binds the ob¬ jects together, and preserves them in unison. Bleostaning, mosaic pavement. Block, a lump of wood or stone. Blocks, pieces of wood in which the sheaves or pulleys ran, and through which the ropes pass. Block cornices and entablatures are frequently used to finish plain build¬ ings, where none of the regular or¬ ders have been employed. Of this kind there is a very beautiful one composed by Vignola, much used in Italy, and employed by Sir Christo¬ pher Wren to finish the second design of St. Paul’s cathedral. Block-house, a building erected by be¬ siegers for the investment of a cas¬ tle. Block-houses were erected in the time of Henry VIII. on the south and south-western coast of England. Blocking-course, a course of masonry or brick-work, laid on the top of a cornice crowming a wall. BLO Blockings, small pieces of wood, fitted in, or glued, or fixed to the interior angle of two boards or other pieces, in order to give strength to the joint. Block-machinery , the machinery for manufacturing ships’ blocks, in¬ vented by the elder Brunei, and adjusted by the late Dr. Gregory. Block-tin, tin cast into blocks or in¬ gots. Blondel (F.), architect, was born at Ribemont, in Picardy, in 1617. Principally employed in the con¬ struction of fortresses, and pub¬ lished several scientific works. Blondel (J. F.), architect, son of the preceding, born in Paris, 1705. He published several very beautiful works. Blondel (J. F.), architecte du Roi, was born at Rouen, in 1683, and stated to be a brother of Frarifois. He was extensively employed as an architect and decorator by the Court, and published many beauti¬ ful works. Blondel (J. B.), architect to the city of Paris. Last of the family. He constructed the Temple, Marche St. Germain, etc. Blood-red heat, the degree of heat which is only necessary to reduce the protuberances on coarse iron by the hammer, in order to prepare it for the file, the iron being pre¬ viously brought to its shape. This heat is also used in punching small pieces of iron. Bloom, a mass of iron after having un¬ dergone the first hammering. Bloom (a), in iron-works, is in form a square piece 2 feet long. Blower, in mining, a smelter. Blowing, the projection of air into a furnace, in a strong and rapid cur¬ rent, for the purpose of increasing combustion. Blow-off cock, the stop-cock in the blow-off pipe. Blow-off pipe, the pipe fixed to the bottom of a boiler, for discharging the sediment, which is effected by blowing through a portion of the water from the boiler. 54 BLO Blow-pipe. The blow-pipe is a most valuable little instrument to the mineralogist, as its effects are strik¬ ing, rapid, well characterized, and pass immediately under the eye of the operator. The most efficacious flame is produced by a regular, mo¬ derate stream of air; while the act of blowing with more force only has the effect of fatiguing the mus¬ cles of the cheeks, oppressing the chest, and at the same time renders the flame unsteady. The student should fill his mouth with air, so as to inflate the cheeks moderately,and continue to breathe without letting the air in the mouth escape ; the blow-pipe may then be introduced between the lips, and while the breathing is carried on through the medium of the nose, the cheeks will expel a stream of air through the blow-pipe ; and by replenishing the mouth at each ex¬ piration, and merely discharging the surplus air through the nostrils, a facility will be acquired of keep¬ ing up a constant stream of air. The best flame for the purpose of this instrument is that of a thick wax candle, such as are made for the lamps of carriages, the wick being snuffed to such a length as to occasion a strong combustion : it should be deflected a little to one side, and the current of air directed along its surface towards the point: a well-defined cone will be pro¬ duced, consisting of an external yellow, and an internal blue flame. At the point of the former, calcina¬ tion, the oxidation of metals, roast¬ ing of ores to expel the sulphur and other volatile ingredients, may be accomplished ; and by the ex¬ treme point of the latter (which affords the most intense heat) fu¬ sion, the deoxidation of metals, and all those operations which require the highest temperature, will he effected. The piece of mineral to be examined must necessarily be supported on some substance; and for the earths, or any subject not BLO being metallic, or requiring the operation of a flux, a spoon or pair of forceps made of platina will be found useful; but, as the metals and most of the fluxes act on pla¬ tina, the most serviceable support, for general purposes, will be a piece of sound, well-burnt charcoal, with the bark scraped off, as free as pos¬ sible from knots or cracks : the piece of mineral to be examined should not in general be larger than a pepper-corn, which should he placed in a hollow made in the charcoal; and the first impression of the heat should be very gentle, as the sudden application of a high temperature is extremely liable to destroy those effects which it is most material to observe. Many substances decrepitate immediately they become hot; and when that is found to be the case, they should be heated red, under circumstances which will prevent their escape: this may be effected, with the earthy minerals, by wrapping them in a piece of platina foil, and, with the metallic ores, by confining them betw-een two pieces of charcoal, driving the point of the flame through a small groove towards the place where the mineral is fixed, by which means a sort of reverberating furnace may be formed. The prin¬ cipal phenomena to be noticed are, phosphorescence, ebullition, intu¬ mescence, the exhalation of vapours having the odour either of sulphur or garlic (the latter arising from the presence of arsenic), decrepita¬ tion, fusibility ; and, amongst the fusible minerals, whether the pro¬ duce is a transparent glass, an opaque enamel, or a bead of metal. Having first made some observa¬ tions on a particle of the mineral alone, either the residue or a fresh piece should be examined with the addition of a flux, more particularly in the case of the ores, as the na¬ ture of the metal may be generally decided by the colour with which it tinges the substance used. The BLOW-PIPE. 55 BLUE. BLO most eligible flux is glass of borax : a piece about half the size of a pea being placed on the charcoal, is to be heated till it melts; the particle of ore being then taken in a pair of forceps, is to be pressed down in it, and the heat applied; or, should the mineral not be inclined to de¬ crepitate, it may be laid on the charcoal, and two or three pieces of glass of borax, about the size of a pin’s head, placed over it; and on using the blow-pipe, the whole will form itself into a globular bead. Blow-valve, the ‘ snifting valve ’ of a condensing engine. Blue, one of the seven primitive co¬ lours of the rays of light, into which they are divided when refracted through a glass prism. Blue-Mack is a well-burnt and levi¬ gated charcoal, of a cool, neutral colour, and not differing from the common Frankfort black. Blue- black was formerly much employed in painting, etc. Blue carmine is a blue oxide of mo- lybdena, of which little is known as a substance or as a pigment. It is said to be of a beautiful blue colour, and durable in a strong light, but is subject to be changed in hue by other substances, and blackened by foul air: we may conjecture, therefore, that it is not of much value in painting. Blue dyes, indigo, Prussian blue, log¬ wood, bilberry, etc. Bluing, the process of heating iron, and some other metals, until they assume a blue colour. Blue John, fluor spar, called so by Derbyshire miners. Blue ochre is a mineral colour of rare occurrence, found with iron pyrites in Cornwall, and also in North America, and is a subphosphate of iron. What Indian red is to the colour red, and the Oxford ochre to yellow, this is to other blue co¬ lours. They class in likeness of character: hence it is admirable rather for the modesty and solidity, than for the brilliancy of its colour. BOA Blue pigments, found in common, are Prussian blue, mountain blue, Bre¬ men blue, iron blue, cobalt blue, smalt, charcoal blue, ultramarine, indigo, litmus, and blue cake. Blue tint, in colouring, is made of ultramarine and white, mixed to a lightish azure. It is a pleasant working colour, and with it should be blended the gradations in a pic¬ ture. It follows the yellows, and with them it makes the greens; and with the red it produces the purples. No colour is so proper for blending down or softening the lights into keeping. In pictures of less value, Antwerp blue may he substituted for ultramarine. Blue verditer is a blue oxide of cop¬ per, or precipitate of the nitrate of copper by lime, and is of a beauti¬ ful light-blue colour. It is little affected by light; but time, damp, and impure air turn it green, and ultimately blacken it, — changes which ensue even more rapidly in oil than in water: it is, therefore, by no means an eligible pigment in oil, and is principally confined to distemper, painting, and the uses of the paper-stainer, though it has been found to stand well, many years, in water-colour drawings and crayon paintings, when kept dry. Blue vitriol, sulphate of copper. Bluff: a bluff-bowed or bluff-headed vessel is one which is full and square forward. Blank, heavy cotton cloth : the term is used in Scotland. Board, a substance of wood contained between two parallel planes; as when the baulk is divided into se-' veral pieces by the pit-saw, the pieces are called boards. Board, in nautical language, the line over which a ship runs between tack and tack. To hoard is to en¬ ter a ship. Boarding -floors are those covered with boards : the operation of . boarding floors should commence as soon as the windows are in, and the plaster dry. 56 BOILERS. BOA Boarding-joists, joists in naked floor¬ ing, to which the boards are fixed. Boar ding -pile e, a pike used by sailors in boarding an enemy’s vessel. Boasting, in masonry, the paring of a stone with a broad chisel and mallet. Boasting, in sculpture or carving, is the rough cutting of a stone to form the outline of a statue or ornament. Boats, small open vessels, impelled on the water by rowing or sailing, having different uses, dimensions, etc., either for river or sea service. Boat-hook, an iron hook with a sharp point, fixed on a pole, at the extre¬ mity. Boatswain, a warrant officer in the navy, who has the charge of the rigging, and calls the crew to duty. Bob, the miner’s engine-beam. Bob, of a pendulum, is the metallic weight which is attached to the lower extremity of a pendulum-rod. Bobstay-holes, those in the fore-part of the knee of the head, for the se¬ curity of the bobstay. Bob-stays, used to confine the bow¬ sprit down to the stem or the cut¬ water. Bocatorium, anciently a slaughter¬ house. Bodium, a crypt, or subterraneous chapel. Body, in physics or natural philoso¬ phy, any solid or extended palpable substance. Body, or solid, in geometry, has three dimensions, length, breadth, and thickness. Bodies are either hard, soft, or elastic. Body-plan, in naval architectural drawing, sectional parts showing fore and after parts of a vessel. Boeria, anciently a manor-house or large country dwelling. Bog, soft, marshy, and spongy matter, or quagmire. Railroads have been made across bogs in Lancashire and in America, by draining, etc., and in the latter by piling as well as draining. Bog-iron ore, an iron ore discoverable in boggy land. BOI Boiler, a wrought-iron vessel contain¬ ing water, to which heat is applied for the generation of steam. Boilers are made of various forms, accord¬ ing to the nature of their applica¬ tion, and are constructed so as to obtain the largest heating surface with the least cubical content. Boilers. Aboiler for 20-horse power is usually 15 feet long and C feet wide; therefore 90 feet of surface, or 4^ feet to 1-horse power ; a boiler for 14-horse power, 60 feet of surface, or 4 - 3 feet to 1-horse power; but engineers allow 5 feet of surface to 1-horse power, and Mr. Hicks, of Bolton, proportions his boilers at the rate of 5£ square feet of hori¬ zontal surface of waterto each horse¬ power : Mr. Watt allows 25 cubic feet of space to each horse-power. Boilers. Iron cement is far preferable to any other material for making iron joints : it has the excellent property, that it becomes more sound and tight the longer it stands, so that cemented joints which at first may be a little leaky, soon be¬ come perfectly tight. The follow¬ ing is the best mode of preparing this iron cement: take 16 parts of iron filings, free from rust; 3 parts powdered sal-ammoniac (muriate of ammonia); and 2 parts of flower of sulphur : mix all together inti¬ mately, and preserve the compound in a stoppered vessel, kept in a dry place, until it is wanted for use. Then take 1 part of the mixture, add it to 12 parts of clean iron filings, and mix this new compound with so much water as will bring it to the consistence of a paste, hav¬ ing previously added to the water a few drops of sulphuric acid. In¬ stead of filings of hammered iron, filings, turnings, or borings of cast iron may be used ; cement, how¬ ever, made entirely of cast iron is not so tenacious and firm as if of wrought iron ; it sooner crumbles and breaks away. It is better to add a certain quantity, at least one- third, of the latter to the former. d 3 57 BOILERS. BOI There is but little ground to fear for the soundness of a well-riveted iron boiler; for in time the action of rust and deposit will stop almost any crevices. In order, however, to take all precaution, it is to be re¬ commended that some clammy sub¬ stance, such as horse-dung, hran, coarse meal, or potatoes, should be boiled in the vessel before it is used. A very small quantity also of the same kind of substance may be put into the boiler when first set to work: this will find its way into the crevices by the pressure within, and, gradually hardening, will soon render the vessel perfectly sound. Boilers. Copper is more tough and less liable to crack than iron, and is a most excellent material for high-pressure boilers : it has, how¬ ever, a less cohesive power; and therefore a greater thickness of me¬ tal is necessary to produce an equal strength : but since copper boilers never fly in pieces in case of explo¬ sion, it is not necessary to be too scrupulous in regard to this point. Even when the metal is thin, espe¬ cially if the diameter is not great, the use of copper removes all dan¬ ger of destructive explosion, since at most only a simple tearing asun¬ der of the metal will ensue. Boiling, or ebullition, the agitation of fluids, arising from the action of fire, etc. Bole, an argillaceous mineral, having a conchoidal fracture, an internal lustre, and a shining streak. Bollards, large posts set in the ground at each side of the docks, to lash and secure hawsers for docking and undocking ships. Bollard timbers, in a ship, two tim¬ bers within the stern, one on each side of the bowsprit, to secure its end. Bolognese School, in painting, a Lom¬ bard school, founded by Caracci. Bolognese School, the great painters of which were,—Francia Agostino, b. 1558, d. 1601; Domenichino, b. 1581, d. 1641; Guido Remi, b. BON 1575, d. 1642; Gio. Lanfranco, b. 1678, d. 1744; Ludovico Caracci, b. 1555, d. 1619; Annibale Ca¬ racci, b. 1560, d. 1609 ; Francesco Albani, b. 1578, d. 1660 ; Guercino, b. 1590, d. 1666. Bolognian stone is derived from sul¬ phate of baryta by calcination and exposure to the rays of the sun. Bolster, a piece of timber placed upon the upper or lower cheek, worked up about half the depth of the hawse-holes, and cut away for the easement of the cable, and to pre¬ vent its rubbing the cheek ; like¬ wise the solid piece of timber that is bolted to the ship’s side, on which the stantients for the linings of the anchors are placed ; or any other small piece fixed under the gun¬ wale, to prevent the main sheet from being rubbed, etc. Bolster, a tool used for punching holes and for making bolts. Bolster of a capital, the flank of the Ionic capital. Bolt, a cylindrical pin of iron or other metal, used for various purposes of fastening, planking, etc. Bolt-auger, an auger of a large size, used by shipbuilders. Bolt-rope, the rope to which the edges of sails are sewed, to strengthen them. Bolt-screwing machine, a machine for screwing bolts, by fixing the bolt- head to a revolving chuck, and causing the end which it is required to screw to enter a set of dies, which advance as the bolt revolves. Bolts, large iron pins. Bolts, long cylindrical bars of iron or copper, used to secure or unite the different parts of a vessel; the prin¬ cipal ironwork for fastening and securing the ship. Bomb-vessel, a strong-built vessel carrying heavy metal for bombard¬ ment. Bomb-ketch, a ship or vessel built with large beams, for carrying and raising of mortars at sea. Bonarroti (Michelangiolo), born 1474, pupil of Domenico Ghir- 58 BONING. BON landajo,—painter, sculptor, and architect: the most eminent of his country for his very great ac¬ quirements in the arts in which he so eminently practised. Bond, in masonry, is that connection of lapping the stones upon one another in the carrying up of the work so as to form an inseparable mass of building. Bond, in bricklaying and masonry, is the arrangement or placing of bricks, etc., so as to form a secure mass of building. Bonders, Bond-stones, Binding stones, stones which reach a considerable distance into, or entirely through, a wall, for the purpose of binding it together. Bond stones, are placed in the thick¬ ness of a wall, at right-angles to its face, to bind securely together. Bond, in carpentry, a term among workmen,—to make good bond by fastening two or more pieces to¬ gether, either tenoned, mortising, or dovetailing. Bond timber, pieces of timber used to bind in brickwork especially. The naked flooring being laid, in carry¬ ing up the second story bond tim¬ bers must be introduced opposite to all horizontal mouldings, as bases and surfaces. It is also customary to put a row of bond timber in the middle of the story, of greater strength than those for the bases and surfaces. Bongrace (a sea term), is a frame of old ropes or junks of cables, laid at the bows, sterns, and sides of ships sailing in cold latitudes, to preserve them from damage by flakes of ice. Bone-brown and Ivory-brown, pro¬ duced by torrefying or roasting bone and ivory, till, by partial charring, they become of a brown colour throughout. Boning, in carpentry and masonry, the art of making a plane surface by the guidance of the eye : joiners try up their work by boning with two straight-edges,which determine whether it be in or out of winding, BOR that is to say, whether the surface be twisted or a plane. Bonnet, in navigation, an additional piece of canvas attached to the foot of a jib, or a schooner’s foresail, by lacings, taken off in bad weather. Bonnets, the cast-iron plates which cover the openings in the valve- chambers of a pump : the openings are made so that ready access can be had when the valves need re¬ pairing. Bonney (mining), a distinct bed of ore, that communicates with no vein. Bonnington. In landscape his practice was to sketch in the outline and general character, and then make accurate studies of the local light and shade and colour. Boom, in ship-building, a long pole run out from different places in the ship, to extend the bottoms of par¬ ticular sails, as jib-boom, flying- jib-boom, studding-sail-boom, etc. Boomkin, in ship-building, a beam of timber projecting from each bow of a ship, to extend the clue or lower corner of the foresail to w'ind- ward. Boor, a parlour, bedchamber, or in¬ ner room. Booth, a stall or standing in a fair or market. Boot-topping, scraping off the grease, or other matter, which may be on a vessel’s bottom, and daubing it over with tallow. Borax, in chemistry, a salt in appear¬ ance like crystals of alum ; an arti¬ ficial salt used for soldering metals. Borcer, an instrument of iron, steel- pointed, to bore holes inlarge rocks, in order to blow them up with gun¬ powder. Bord, anciently a cottage. Bore, in hydrography, a sudden and abrupt influx of the tide into a river or narrow strait. Boreas, the north wind. Borer, a boring instrument, with a piece of steel at the end, called a boring-bolt. Boring, the art of perforating or mak- 59 BORING. BOR ing a hole through any solid body ; as boring the earth for water; boring water-pipes, either wood, iron, zinc, or lead; boring cannon, etc. Boring. Modern steam-engines depend on the improved method of boring their cylinders. The cylinder to be bored is firmly fixed with its axis parallel to the direction in which the borer is to move : the cutting apparatus moves along a bar of iron accurately turned to a cylindrical form. Boring-bar, a bar of a small horizontal boring-machine: it is used for bor¬ ing the brasses of plummer-blocks, by means of a cutter fixed in it. Boring-collar, in turning, a machine having a plate with conical holes of different diameters : the plate is movable upon a centre, which is equidistant from the centres or axes of the conical holes; the axes are placed in the circumference of a circle. The use of the boring- collar is to support the end of a long body that is to be turned hol¬ low, and which would otherwise be too long to be supported by a chuck. Boring-lathe, a lathe used for boring wheels or short cylinders. The wheel or cylinder is fixed on a large chuck, screwed to the mandril of a lathe. Boring-machine, a machine for turn¬ ing the inside of a cylinder. Boromino (F.), born in Bissano, near the Lago di Lugano, in 1509. He was architect in the service of the family of the Visconti, and was architect of superb taste ; many of his buildings are finely portrayed in M. Letarouilly’s great work on Rome. Boron, in chemistry, is an olive-green powder, which, heated out of the air, becomes harder, and darker in colour : it burns brilliantly when heated in air or oxygen, forming boracic acid. Bosco (Jean de Sacro), a celebrated mathematician of the thirteenth BOT century, who was so called from Ho- lywood, a town in England of that name, which was his birth-place. After studying in the University of Oxford, he went to Paris and ac¬ quired great reputation by his knowledge of mathematics. He has left two works, valuable for their time, one entitled, ‘ De Sphaera Mundi; ’ the other, ‘De Computo Ecclesiastico.’ They are printed in one volume. Boss, a sculptured keystone or carved piece of wood, or moulded plaster, placed at intervals of ribs or groins in vaulted and flat roofs of Gothic structures. Boss, a short trough for holding mor¬ tar when tiling a roof : it is hung to the laths. Bossage, projecting stones laid rough in building, to be afterwards cut into mouldings or ornaments. Bosquet, a French expression for a piece of ground in gardens, en¬ closed by a palisade or high hedge¬ row of trees, etc. Botany Bay oak, resembling in colour full red mahogany, is' used as ve¬ neer for the backs of brushes, turn¬ ery, etc. Bottle-glass, a composition of sand and lime, clay, and alkaline ashes of any kind. Bottom - captain, a superintendent over the miners in the bottoms. Bottom-heat, artificial temperature, produced in hothouses. Bottom-lift, in mining, the deepest or bottom tier of pumps. Bottom-rail, in joinpry, the lowest rail of a door. Bottoms, in mining, the deepest work¬ ing parts of a mine, wrought either by sloping, driving, or otherwise breaking the lode. Bottoms in fork. In Cornwall, when all the bottoms are unwatered, they say, ‘the bottoms are in fork;’ and to draw out the water from them, or any dippa, or any other particular part of a mine, is said to be ‘ forking the water;’ and when accomplished, such dippa, etc., is GO BOW. BOW BOU ‘ in fork.’ Likewise when an en¬ gine has drawn out all the water, they say, ‘ the engine is in fork.’ Boudoir, a small retiring-room. Boulders, fragments of rocks trans¬ ported by water, and found on the sea-shore. Boulder walls, walls built of the above. Boultine, in architecture, a convex moulding, whose periphery is a quarter of a circle, next helow the plinth in the Doric and Tuscan orders. Bounds, in mining, signifies the right to tin ore over a given district. Boulevard, promenades around a city, shaded by avenues of trees. Bourgeois (Nicolas), an Augustin, was the inventor of the pont-tournant. A reward of 1200 livres a year was offered to him w T ho should invent a movable bridge to be placed over the ditch of the Tuileries. Bourse, a public edifice for the as¬ semblage of merchants to consult on matters of business or money, an exchange. Boutant; in architecture, an arc-bou¬ tant is an arch, or buttress, serving to sustain a vault, and which is it¬ self sustained by some strong wall or massive pile. Bova, anciently a wine-cellar. Bovey coal, wood-coal found at Bovey, in Devonshire. Bow, the round part of a ship forward. Bow, anciently an arch or gateway. Bow-compass, for drawing arches of very large aisles ; it consists of a beam of wood or brass with three long screws that bend a lath of wood or steel to any arch. The term also denotes small compasses employed in describing arcs too small to be accurately drawn by the common compasses. Bow and string bridge, or bow-string or tension bridge; in which the horizontal thrust of the arch, or trussed beam, is resisted by means of a horizontal tie attached as nearly as possible to the chord line of the arch. Bow and string beam, a beam so trussed that the tendency of the straight part to sag when loaded is counteracted to some extent by the tension upon its two ends, by a bow of wood or metal attached to those extremities. Bower cables, for ships. Table showing the differentkinds of best bower cables at present em¬ ployed in the British navy, with the corresponding iron cables, and the proof-strain for each: Best bower hempen Diameter and cables, 100 fathoms. Number Breaking weight of the bolt Strain Rates of Ships. of of the iron cable for the Cir- Weight. threads experiment. substituted for proof. cumf. in each. the preceding. in. cwt. qr. lb. tons. cwt. qr. tons. First-rate, large . 25 114 2 7 3240 1 middle 24 105 2 17 2988 ! 24 inches, j 218 cwt. small . 23 96 2 27 27361 1 81 Second-rate . . 23 96 2 27 2736 ) 114 0 0 Third, large . . 23 96 2 27 2736 J J small . . 22 89 0 12 2520 \ 89 0 0 r 2 inches. }72 Fourth, 60 guns . 21 80 0 22 2268 / 1186 cwt. 2 qrs. 58 do. . 19 66 0 21 1872 / If inch. }63 50 do. . 184 62 1 14 1764 \ 170 cwt. 2 qrs. Fifth, 48 do. . 46 do. "i 42 do. / 18 174 68 56 2 0 6 1 1656 1584 63 0 0 1 13 inch, j 145 cwt. 3 qrs. ]■ 55 Sixth, 28 do. . 144 38 0 21 1080 40 0 0 r If inch. \ 87 cwt. 2 qrs. }34 Ship, sloop . . 134 33 0 10 936 . f 14 inch. ^ 28 Brig, large . . 134 33 0 10 936 1 74 cwt. 3 qrs. Ditto small . . 11 21 2 15 612 / 14 inch. 1 6l cwt. 1 qr. } 23 61 BOW BOWLS. BRA From the preceding Table the im¬ mense advantage of iron cables will be distinctly seen, and particularly when it is considered that a hempen cable, on a rocky bottom, is de¬ stroyed in a few months, while the other will sustain no perceptible injury. Bow and string girder , a wrought- iron bow and string girder, pa¬ tented by Mr. G. Nasmyth. Bower, anciently a small enriched chamber for ladies; a private room, or parlour, in ancient castles and mansions. Bower, a working anchor, the cable of which is bent and veered through the hawse-hole. Bower, in navigation, two anchors thus named from their being car¬ ried at the bow T . Boweric, in the East Indies, a well descended by steps. Bow-grace, a frame of old rope or junk, placed round the bows and sides of a vessel, to prevent the ice from injuring her. Bowge (a sea term), a rope fastened to the middle of the sail, to make it stand closer to the wind. Bow-line, in navigation, a rope lead¬ ing forward from the leach of a square sail, to keep the leach well out, when sailing close-hauled. Bowling-alley, a place where the game and exercise of bowling is carried on. Bowl, bowling, or bowline (in a ship), a round space at the head of the mast for men to stand in. Bowling-green. Bowling, an ancient English game, which was usually attached to the private grounds during the 16th, 17th, and 18th centuries. Bowls of silver were used as drinking- glasses are now, before the intro¬ duction of glass for such purposes ; they were of small sizes, in ‘ nests’ fitting one within another. Of the larger-sized bowl, the most distin¬ guished are the mazer and the wassail. Mazer is a term applied to large goblets, of every kind of material ; but the best authors agree that its derivation is from maeser, which, in Dutch, means maple ; and therefore that a mazer bowl was originally one formed of maple-wood. Bow-saw, a saw used for cutting the thin edges of wood into curves. Bowse, to pull upon a tackle. Bowse away, a sea phrase, to pull all together. Bowsprit, in ship-building, a large boom or mast which projects for¬ ward over the stem to carry sail. Bowtel, the shaft of a clustered pillar, or a shaft attached to the jambs of a door or window. Box, for mitring, a trough for cutting mitres: it has three sides, and is open at the ends, with cuts in the vertical sides at angles of 45° with them. Box-drain, an underground drain built of brick and stone, and of a rectangular section. Box of a rib-saw, two thin iron plates fixed to a handle, in one of which plates an opening is made for the reception of a wedge, by which it is fixed to the saw. Box-haul, to veer a ship in a manner when it is impossible to tack. Box the compass, to repeat thirty-two points of the compass in order. Boxing-off, throwing the head sails aback, to force the ship’s head ra¬ pidly off the wind. Boxings of a window, the cases oppo¬ site each other on each side of a window, into which the shutters are folded. Box-wood is of a yellow colour, in¬ clining to orange ; is a sound and useful wood, measuring from 2 to 6 feet long, and 2^ to 12 inches in diameter : it is much used by wood- engravers; for clarionets, flutes; for carpenters’ rules, drawing-scales, etc. Much of it comes from Box Hill, in Surrey, and from several districts in Gloucestershire, also from other parts of Europe. Boziga, anciently a house or dwelling. Brace, a piece of slanting timber, used 62 BRA BRAMAH’S PRESS. BRA in truss partitions, or in framed roofs, in order to form a triangle, and thereby rendering the frame immovable : when a brace is used by way of support to a rafter, it is called a strut: braces in partitions and span roofs are always,or should be, disposed in pairs, and placed in opposite directions. Brace, an instrument into which a vernier is fixed ; also part of the press-drill. Brace, a rope by which a yard is turned about. Braces, that security for the rudder which is fixed to the stern-post and to the bottom of a ship. Bracket plummer-block, a support for a shaft to revolve in, formed so that it can be fixed vertically to the frame of a machine, or to a wall. Brackets, ornaments: the hair bracket in ship-building is the boundary of the aft-part of the figure of the head, the lower part of which ends with the fore-part of the upper cheek. The console bracket is a light piece of ornament at the fore¬ part of the quarter-gallery, some¬ times called a canting-hose. Brackets, the cheeks of the carriage of a mortar; a cramping-iron to stay timber-work; also stays set under a shelf, to support it. Bracket-stairs. “ The same method must be observed, with regard to taking the dimensions and laying down the plan and section, as in dogling-stairs. In all stairs what¬ ever, after having ascertained the number of steps, take a rod the height of the story, from the surface of the lower floor to the surface of the upper floor; divide the rod into as many equal parts as there are to be risers; then, if you have a level surface to work upon below the stairs, try each one of the risers as you go on: this will prevent any defect.” Brad, a small nail with a projecting head on one edge. Brad-awl, the smallest boring tool used by a carpenter; its handle is the frustum of a cone tapering downwards ; the steel part is also conical, but tapering upwards, and the cutting edge is the meeting of two basils, ground equally from each side. Brails, in navigation, ropes by which the foot or lower corners of fore- and-aft sails are hauled up. Brake, the apparatus used for retard¬ ing the motion of a wheel by friction upon its periphery. Brake, the handle of a ship’s pump. Brake, a machine used in dressing flax. Brake-wheel, the wheel acted upon by a brake. Bramah's hydrostatic press consists in the application of water to en¬ gines, so as to cause them to act with immense force; in others, to communicate the motion and powers of one part of a machine to some other part of the same machine. This press was constructed in Woolwich dockyard for testing iron cables, and the strain is pro¬ duced by hydrostatic pressure: its amount is estimated by a system of levers balanced on knife-edges, which act quite independently of the strain upon the machine, and exhibit sensibly a change of pres¬ sure of £th of a ton, even when the total strain amounts to 100 tons. This proving-machine was con¬ structed by Messrs. Bramah, of Pimlico, and is doubtless one of the most perfect of the kind which has been executed. It consists of two cast-iron sides, cast in lengths of 9^ feet each, with proper flanges for abutting against each other, and for fixing the whole to sleepers resting on a secure stone founda¬ tion. The whole length of the frame is 104£ feet, equal to ^th the length of a cable for a first-rate ; so that the cables are tested in that number of detached lengths, which are afterwards united by shackle- bolts. The press is securely bolted down at one end of the frame, and the cylinder is open at both ends. 63 BRASS. BRA The solid piston is 5£ inches in diameter in front and 10^ inches behind, so that the sdrface of pres¬ sure is the difference of the two, viz. ^2lJ 2 __21| ^ x •7854 = 65ii nC hes. The system of levers hung on knife-edges is attached to the other end of the frame, and the cable is attached by bolt-links to this and to the end of the piston-rod. The levers being properly balanced, and the cable attached to a short arm rising above the axis, this draws the other arm downwards; and at a distance equal to twelve times the short arm, is a descending pin and hall, acting in a cup placed on the upper part of the arm of the second lever, and this again acts on a third. The first two levers are under the floor, and pass ultimately into an adjacent room, where a scale carry¬ ing weights is conveniently placed, and the whole combination is such that every pound in the scale is the measure of a ton strain: the whole acts wdth such precision that £th of a pound, more or less, in the scale, very sensibly affects the balance. At the same place is situated a scale, acted upon by the water-pressure from the charge-pipe of the press, and the valve in this^pipe is of such dimen¬ sions that, together with the lever by which it acts, the power is again such that a pound should balance a ton; but the friction is here so great that it requires several pounds to make a sensible change in the apparent balance, and for this rea¬ son this scale is never used. The forcing-pumps are in another adja¬ cent room, and are worked by han¬ dles, after the manner of a fire en¬ gine. At first, six pistons are act¬ ing, and the operation proceeds quickly; but as the pressure and strains increase, the barrels are suc¬ cessively shut off, till at length the whole power of the men is em- BRA ployed on one pair of pumps only, and on this the action is conti¬ nued till the proofstrain is brought on the cable. A communication is then opened between the cistern and cylinder, and everything is again restored to equilibrium. Eramley Fall stone, a sandstone of the Millstone Grit formation quar¬ ried in the township of Bramley in Yorkshire. Branch, in mining, a leader, string, or rib of ore, that runs in a lode; or if a lode is divided into several strings, they are called branches, w hether they contain ore or not: likewise strings of ore which run transversely into the lode are called branches ; and so are all veins that are small, dead or alive, i. e. whe¬ ther they contain ore or not. Branched-worlc, carved and sculp¬ tured leaves and branches in monu¬ ments and friezes. Branches, anciently the ribs of groin¬ ed ceilings. Brandishing or Brattisliing, a term used for carved-work, as a crest, battlement, or other parapet. Brandrith, a fence or rail round the opening of a well. Brass, a factitious metal, made of copper and zinc. Brass, in the middle ages, a plate of metal inserted or affixed to a flat gravestone. Brasses (Sepulchral ), monumental plates of brass or mixed metal, an¬ ciently called latten, inlaid on large slabs of stone, which usually form part of the pavement of a church, and represent in their outline, or by lines engraved upon them, the figure of the deceased. Brattisliing , anciently, carved open¬ work. Bray, anciently, a bank or earthen mound. Brazil-wood, the wood of Ccesalpinia echinata, which yields a red dye: it is imported principally from Per¬ nambuco : the tree is large, crook¬ ed, and knotty; and the bark is thick, and equals the third or fourth 64 BREAK. BRA of its diameter. Its principal use is for dyeing : the best pieces are selected for violin-bows and turn¬ ery. Braziletto-wood is of a ruddy orange colour, principally used for dyeing, and for turnery and violin-bows. Brazing, the soldering together of edges of iron, copper, brass, etc., with an alloy of brass and zinc called spelter solder. Breadth is applied to painting when the colours and shadows are broad and massive, such as the lights and shadows of the drapery ; and when the eye is not checked and dis¬ tracted by numerous little cavities, but glides easily over the whole. Breadth of colouring is a promi¬ nent character in the painting of all great masters. Break, in shipping. To break bulk, is to begin to unload. Break, a projection or recess from the surface or wall of a building. Break joint, constructively, to dis¬ allow two joints to occur over each other. Breaker, a small cask for water. Breaking down, in sawing, is dividing the baulk into boards or planks. Breaking joint, in joinery, is not to allow two joints to come together. Breakwater, a human contrivance to ward off and diminish the force of waves, to protect harbours, sta¬ tions, etc., from the violence of tem¬ pestuous gales. Some stupendous works have been executed for these purposes, especially that at Ply¬ mouth, by the late John Rennie. Breaming, cleaning a ship’s bottom by burning. Breast, in mining, the face of coal- workings. Breast-fast, a rope used to confine a vessel sideways to a wharf or to some other vessel. Breast-hooks, pieces of compass or knee-timber, placed withinside a ship, to keep the bows together. The deck-holes are fayed to the timbers, and placed in the direction of the decks: the rest are placed BRE one between each deck, and as many in the hold as are thought needful; all of which should be placed square with the body of the ship, and fayed on the planks. Breast-hooks are the chief security to keep the ship’s bows together ; therefore they require to be very strong and well secured. Breast-knees are placed in the for¬ ward part of a vessel, across the stem, to unite the bows on each side. Breast-plate, that in which the end of the drill opposite the boring end is inserted. Breast-rail, the upper rail of the bal¬ cony or of the breastwork on the quarter-deck. Breast-rope, a rope passed round a man in the chains, wdiile taking soundings. Breast-ivheel, in mill-w T ork, a form of water-wheel in which the water is delivered to the float-boards at a point somewhat between the bot¬ tom and top. Buckets are seldom employed on breast-wheels. Breastwork, the stantients with rails on the quarter-deck and forecastle. The breastwork fitted on the up¬ per deck of such ships as have no quarter-deck serves to distinguish the main-deck from the quarter¬ deck. Breastwork, a mass of earth raised to protect troops from the fire of an enemy. Breech, the angle of a knee-timber, the inside of which is called the throat. Breechings, in a ship, are ropes by which the guns are lashed fast or fastened to the ship’s side. Breeze, small ashes and cinders used instead of coal for the burning of bricks. Breostweall, anciently, a breast-high wall. Bressummer, a beam supporting a su¬ perincumbent part of an exterior wall, and running longitudinally below that part. Brest, in architecture, is that co- 65 BRICKS. BRE lumn which is called the thorus or tore. Bretachice, anciently, wooden towers, attached to fortified towns. Brewhouse, a building specially built and appropriated for the brewing of beer. Bride. “ Let us make brick, and burn them thoroughly. And they had brick for stone, and slime had they for mortar.”— Gen. xi. 3. Bricks are a kind of factitious stone, composed of argillaceous earth, and frequently a certain portion of sand, and cinders of sea-coal (called breeze), tempered together with water, dried in the sun, and burnt in a kiln, or in a heap or stack called a clamp. For good brick¬ making, the earth should be of the purest kind, dug in autumn, and exposed during the winter’s frost; this allows the air to penetrate, and divide the earth particles, and facilitates the subsequent opera¬ tions of mixing and tempering. The Romans made bricks of va¬ rious sizes, from 1 foot to 2 feet in length, from 7 inches to 9 inches in breadth, and from 3-j inches to If in thickness. Roman bricks found in the old Roman wall at Veru- lam, compared with modern bricks, show the superiority of the old to the new, the Roman bricks be¬ ing lighter and better burnt than the modern. The brick remains of the period of the Roman empire are more en¬ tire than the stone. Bricks were found at Toulouse, quite sharp at the edges, and not altered hy time; they measured 14 inches long, 9 inches broad, and thick. These bricks formed the founda¬ tion all around the building. The arches were formed of them for entrances; and round, large, water- worn pebbles of quartz, with mor¬ tar, formed the walls of the Circus, resting on the brick arches. Mr. Layard, in his work on Ni¬ neveh, says—“The soil,an alluvial deposit,was rich and tenacious: the BRI builders moistened it with water, and adding a little chopped straw, that it might be more firmly bound together, they formed it into squares, which, when dried by the heat of the sun, served them as bricks. In that climate, the pro¬ cess required but two or three days. Such were the earliest building materials, and as they are used to this day, almost exclusively, in the same country. “ The Assyrians appear to have made much less use of bricks baked in the furnace than the Babylo¬ nians, no masses of brickwork, such as are everywhere found in Babylonia Proper, existing to the north of that province. Common clay moistened with water, and mixed with a little stubble, formed, as it does to this day, the mortar used in buildings ; but, however simple the materials, they have suc¬ cessfully resisted the ravages of time, and still mark the stupendous nature of the Assyrian structures. “ This mode of brick-making is described by Sanchoniathon : The people of Tyre invented the art of brick-making and of building of huts; after them came two brothers: one of them, Chrysor or Hyphags- tus, was the first who sailed in boats; his brother invented the way of making walls with bricks. From the generation were born two youths, one called Technites and the other Genius Autochthon. They discovered the method of mingling stubble with the loam of the bricks, and drying them in the sun; they also invented tiling.” Bricks. Some of Palladio’s finest ex¬ amples are of brick : the cortile of the Carita at Venice is an instance. The interiors of the Redentore and St. Giorgio, in the same city, have but a coat of plaster on them ; the beautiful PalazzoThiene at Vicenza, at least that part which was exe¬ cuted, is left with its rockworked basement in brickwork chipped out. Form alone fastens on the mind in 66 BRIDGE. BRI works of art; the rest is meretri¬ cious, if used as a substitute to su¬ persede this grand desideratum. Brick-axe, used for axing off the soffits of bricks to the saw-cuttings, and the sides to the lines drawn: as the bricks are always rubbed smooth after axing, the more truly they are axed, the less labour there will be in rubbing. Brick groins, the intersecting or meet¬ ing of two circles upon their dia¬ gonal elevations, drawn upon the different sides of a square, whose principal strength lies in the united force of elevation divided by geo¬ metrical proportions to one certain gravity. Bricklaying, the art by which bricks are joined and cemented, so as to adhere as one body. This art, in London, includes the business of walling, tiling, and paving with bricks or tiles. Brick-nogging, brickwork carried up and filled in between timber fra¬ ming. Brick trimmer, a brick arch abutting upon the wooden trimmer under the slab of a fire-place, to prevent the communication of fire. Brick-trowel, a tool used for taking up mortar and spreading it on the top of a wall, to cement together the bricks, etc. Bridge, a constructed platform, sup¬ ported at intervals, or at remote points, for the purpose of a road¬ way over a strait, an inlet or arm of the sea, a river or other stream of water, a canal, a valley or other depression, or over another road: it is distinguished from a cause¬ way, or embanked or other con¬ tinuously supported roadway, and from a raft, by being so borne at intervals or at remote points. Constructions of the nature and general form and arrangement of bridges,—such as aqueducts and viaducts ; the former, being to lead or carry streams of water or canals, and the latter, to carry roads or railways upon the same, or nearly BRI the same level, over depressions,— are in practice considered as bridges, although they are not such in the commonly received sense of the term. Taken, however, in the sense which the most plausible ety¬ mology that has been suggested of the term would require, the word ‘bridge’ being formed by prefixing the constructive be to ridge, a bridge is an elevated construction upon, or over a depression, and between depressed points. There are bridges built of the materials, stone, brick, iron, timber, wire, and on the principles of sus¬ pension ; for the explanation of which, see the word Suspension. The bridge across the Zab, at Lizari, is of basket-work. Stakes are firmly fastened together with twigs, forming a long hurdle,reach¬ ing from one side of the river to the other. The two ends are laid upon beams, resting upon piers on the opposite banks. Both the beams and the basket-work are kept in their places by heavy stones heaped upon them. Animals, as weli as men, are able to cross over this frail structure, which swings to and fro, and seems ready to give way at every step. These bridges are of frequent occurrence in the Tiejari mountains. Bridges. The principal object to be observed in forming the plan of a bridge, is to give a suitable and convenient aperture to the arches, so as to afford a free vent to the waters of sudden floods or inunda¬ tions, and to secure the solidity and duration of the edifice by a skilful construction. The solidity of a bridge depends almost entirely on the manner in which its foundations are laid. When these are once pro¬ perly arranged, the upper part may be erected either with simplicity or elegance, without impairing in any degree the durability of the structure. Experience has proved that many bridges either'decay, or are swept away by sudden floods, 67 BRI BRITTLENESS. BRO by reason of the defective mode of fixing their foundations, while very few suffer from an unskilful con¬ struction of the piles or arches. This latter defect, however, is easy of correction, nor is it difficult to prevent the consequences that might be expected from it. In the projection of a bridge, five principal points are necessary to be considered,—first, the choice of its position or locality ; secondly, the vent, or egress that must be allowed to the river; thirdly, the form of the arches ; fourthly, the size of the arches ; fifthly, the breadth of the bridge. Bridge-board, or notch-board, a board on which the ends of the steps of wooden stairs are fastened. Bridged gutters are made with boards supported by bearers, and covered above with lead. Bridge-stone , a stone laid from the pavement to the entrance-door of a house, over a sunk area, and sup¬ ported by an arch. Bridging-floors, floors in which bridg¬ ing-joists are used. Bridging-joists are the smallest beams in naked floorings, for supporting the boarding for walking upon. Bridging-pieces, pieces placed be¬ tween two opposite beams, to pre¬ vent their nearer approach, as rafters, braces, struts, etc. Bridle, the spans of rope attached to the leaches of square sails, to which the bowlines are made fast. Bridle-cable, in navigation. When- a vessel is moored by laying down a cable upon the ground, with an anchor at each end, then another cable attached to the middle of the ground cable is called bridle-cable. Bridle-part, the foremost part, used for stowing the anchors. Brig, a square-rigged vessel with two masts. Brine-pump, the pump in a steam¬ ship, used occasionally for drawing off a sufficient quantity of water, to prevent the salt from depositing in the boiler. Brettingham (M.), an architect of some eminence of more than a cen¬ tury ago; built Norfolk House, in St. James’s Square, in 1742; Lang¬ ley Park, in Norfolk, in 1740-44, etc. Brittleness, in iron, is a want of tena¬ city or strength, so as to be easily broken by pressure or impact: when iron is made too hot, so as to be nearly in a state of fusion, or so hard as to resist the action of the file, this is called the dispo¬ sition of cast iron. Broach, an old English term for a spire; still in use in some parts of the country to denote a spire springing from the tower without any intermediate parapet. Broach-to, to fall off so much, when going free, as to bring the wind round on the other quarter, and take the sails aback. Broadside, the whole side of a vessel. Broken back, the state of a vessel when she is so loosened as to droop at each end. Bromine , in chemistry, is found com¬ bined with silver in a few ores, also iii sea-water and salt-springs; as bromide of potassium, sodium, or magnesium. Brontern, in Greek architecture, bra¬ zen vessels placed under the floor of a theatre, with stones in them, to imitate thunder. Bronze, a compound metal, made of from 6 to 12 parts of tin and 100 parts of copper. Brood, in mining, any heterogeneous mixture among tin or copper ore, as Mundick, Black Jack, etc. Browning, a process by which the surfaces of articles of iron acquire a shining brown lustre : the mate¬ rial used to produce this is the chloride of antimony. Brown (Sir Samuel), Captain, R.N. engineer of the chain-pier at Brighton; he was the first to in¬ troduce the bar-link. Sir S. Browm has stated that at Brighton he found the impetus of the waves during heavy gales 68 BUFFET. BRO was “ equal to SOlbs. to afoot upon a cylindrical column of 12 inches diameter.” The hydrostatical pres¬ sure of a wave only 1| foot high is equal to 801b. upon a square foot. Brown ink. Various compounds were used in sketching by Claude, Rem¬ brandt, and many of the old mas¬ ters, the principal of which were solutions of bistre and sepia. Broxcn ochre, Spruce ochre, or Ochre de Rue, a kind of dark-coloured yellow ochre : it is much em¬ ployed, and affords useful and per¬ manent tints. This and all natural ochres require grinding and wash¬ ing over, to separate them from extraneons substances ; and they acquire depth and redness by burn¬ ing. Brown-pink , a fine glazing colour having but little strength of body. In the flesh, it should never join or mix with the lights, because this colour and white antipathize and mix of a warm dirty hue; for which reason their joinings should be blended with a cold middle tint. Brown-post, a name given by some builders to a beam laid across a building. Brown spar, a magnesian carbonate of lime, tinged by oxide of iron and manganese. Bruiser, a concave tool used in grind¬ ing the specula of telescopes. Brunswick green, a pigment com¬ posed of carbonate of copper with chalk or lime. Brush-wheels are used in light ma¬ chinery, to turn each other by means of bristles or brushes fixed to their circumference. Buata, anciently an arch of chamber ; a crypt. Bucca, anciently an almonry. Bucentaur, the name of the once ce¬ lebrated galley of Venice, used by the Doge on Ascension-day, to ce¬ lebrate the wedding of the Adria¬ tic, by dropping a ring into that sea. Buckers, in mining, bruisers of the ore. BUF Buckets, in water-wheels, a series of cavities placed on the circumfer¬ ence of the wheel, and into which the water is delivered, to set the wheel in motion. By the revolu¬ tion of the wheel the buckets are alternately placed so as to receive the water, and inverted so as to discharge it, the loaded side al¬ ways descending. Bucking, in mining, a term applied to a method of breaking the poor foul copper ore smaller by hand, with small flat irons, called bucking- irons, into order to wash and se¬ parate the pure ore from the use¬ less waste : the same term is used in the lead-mines; but Pettus, in his ‘ Plata Miner,’ gives it the sig¬ nification of washing or wet-stamp¬ ing ores. Bucking-iron, in mining, the tool with which the ore is pulverized. Buckler, a shield of armour, anciently used in war. Bucklers, in ships, blocks of wood made to fit in the hawse-holes, or holes in the half-ports, when at sea. Bucranes, in sculpture, the heads of oxen, flayed and lacerated, some¬ times represented on friezes. Buddie, in mining, a pit dug in the earth near the stamping-mill, 7 feet long, 3 feet wide, and 2^ feet deep, where the stamped tin is cu¬ riously washed from its impuri¬ ties by water constantly running through the buddle, while a boy, called a buddle-boy, is standing in the body of it, and working both with a shovel and with his feet. Budget, a pocket used by tilers for holding the nails in lathing for tiling. Buffers, rods with enlarged ends or striking-blocks projecting from the ends of the frame of a railway carriage, and attached to springs, for deadening the shocks received from the engines. Buffet, a table with long narrow shelves over it; a convenient 69 BUH BUILDINGS. BUL piece of furniture for a sitting room. Buhl, unburnished gold. Buhl-work, ornamental furniture, in which tortoise-shell is inlaid with wmod and brass. Builder, a term applied both in civil and naval architecture: in the for¬ mer the builder is mostly employed under the superintendence of an architect, by contract, or at mea¬ sure and value ; in the latter, under the naval architect, mostly by contract. Building, the art which comprises all the operations of an architect in building with stone, brick, timber, iron, cement, etc. Buildings. Of the aspects best adapted to convenience and health, for the different kinds of buildings, Vitru¬ vius writes : “ The principles which should be attended to in allotting to each kind of building an appro¬ priate aspect remain to be explain¬ ed : the winter eating-rooms and baths ought to face the winter- west, because the use of them re¬ quires that they should be light at the time of the sun’s setting : be¬ sides which, the western sun, be¬ ing immediately opposite to them, renders their temperature mild at the close of the day. The sleeping apartments and libraries should be made to front the east, because the morning light is necessary for them; and books are better preserved when the air and light are received from that quarter. When libraries have a southern or western aspect, they admit those winds which, at the same time that they carry with them moths, instil also damp va¬ pours into the books, which, in process of time, cause their decay. The vernal and autumnal triclinia should face the east, because the windows being turned from the sun’s rays, whose heat increases as the sun advances towards the west, their temperature is cool at the hours they are generally used. The summer triclinia should front the north ; because, having that aspect, they will be least exposed to the sun, and the temperature of the apartments will be grateful, at the same time that it is conducive to health. No other aspect possesses equal advantages ; for the sun, dur¬ ing the solstice, would render the air of all others sultry. This as¬ pect is necessary for pinacothecae and the apartments in which the pursuits of embroidery and paint¬ ing are followed, because the colours used in works of this kind retain their brightness longer when exposed to an equable and regular light.” — Wilkins’s Vit. p. 220. Buildings Act, an Act of Parliament passed in the 18th and 19th of Victoria, to regulate the construc¬ tion of buildings generally, and appurtenances thereto, and to de¬ termine their supervision by dis¬ trict surveyors and referees. Building of beams, the joining of two or several pieces of timber together in one thickness, and of several pieces in one length, by means of bolts, so as to form a beam of given dimensions, which it would be im¬ possible to obtain from a single piece of timber. Buleuteria, among the Greeks, coun¬ cil-chambers or public halls. Bulge, that part of a ship which bulges out at the floor-heads, to assist the ship w'hen taking the ground. Bulge-way, a large piece of timber, or pieces bolted together, making one solid piece, placed under the bulge of a ship, to support her launch. The support of the bulge- ways to lie on is called ways, which sometimes are placed straight and sometimes cumber : but if they do cumber, it should be truly circu¬ lar ; though sometimes the curve is quicker at the lower part, hut this is liable to strain the sheer of the ship. Their extreme distance is generally about one-third the breadth of the ship, but this must 70 BURDEN. BUL depend on the form of the mid¬ ship bend. Bulk,the contents of the hold of a ship. Bulkar, a beam or rafter. Bulk-heads, partitions built up in se¬ veral parts of a ship, to form and separate the various apartments. Bullanlic, so-called ornamental capi¬ tal letters, used in apostolic bulls. Bullen-nails, such as have roundheads with short shanks, turned and lac¬ quered, used principally for hang¬ ings of rooms. Bullet-wood, from the West Indies, is the produce of a large tree with a white sap; is of a greenish ha¬ zel, close and hard; used in the country for building purposes. Bullet-wood, another species, from Berbice, is of a hazel-brown colour, adapted to general and eccentric turning. Bull's-eye, a small circular aperture for the admission of light or air. Bull's-eye, a small oval block of hard w'ood without sheaves, having a groove round the outside, and a hole in the middle. Bulwarks, the woodwork round a vessel, above her deck, consisting of boards fastened to stanchions and timber-heads. Bumboats, those which lie alongside a vessel in port with provisions for sale. Bumpkins, pieces fitted above the main-rail in the head, which ex¬ tend nearly as far forward as the fore-part of the knee of the head, and are for the use of hauling down the fore-tack. Bunch, or Bunchy: a mine that is sometimes rich and at other times poor, is said to be bunchy. Bunch, or Squat, in mining, a quan¬ tity of ore, of small extent, more than a stone and not so much as a course : a mine is said to be bunchy when these are found in place of a regular lode. 1 Bundle-pillar, a column or pier, with others of small dimensions attached to it. Bunny, in mining, of tin or copper BUR ore ; a sombrero in Alonzo Barba; a pipe of ore ; a great collection of ore without any vein coming into or going out from it. Bunt of a sail, the middle part formed into a bag or cavity, that it may gather more wind. Buntine, thin woollen stuff, of which a ship’s colours are made. Bunt-line cloth, the lining sewed up the sail in the direction of the bunt-line, to prevent the rope from chafing the sail. Bunt-lines, ropes fastened to cringles on the bottoms of the square sails, to draw them up to their yards. Buoy, a cask, or block of wood, fast¬ ened by a rope to an anchor, to point out shoals or particular spots. Burden, in mining, the tops or heads of Streamwork which lie over the stream of tin, and which must be first cleansed. Burdon, a pilgrim’s staff. Bureau, a chamber or office for the transaction of state or business af¬ fairs. Burges, the Persian word for Towers, evidently the same as the Gothic burgh ; a fortified dwelling or en¬ closed town. Gird or yard is in Persian a city or fortress, which approximates to garth, an enclo¬ sure in the Gothic : hence garden. But a castle, comprehendingtowers and walls, is in Persian calaa. Burgundy pitch, a resin collected from the spruce fir. Burgus, anciently a number of houses protected by a fortress. Burgward, anciently the custody or keeping of a castle. Burgwork, anciently applied to a castle or borough. Burin, an engraver’s instrument ; a graver. Burners, for gas-light. Coal gas has now been used for the purposes of artificial illumination nearly fifty years, and the burners sanctioned by the companies at the present day are of several shapes. Carburetted hydrogen of the spe¬ cific gravity ’390 (which is about 71 BUR BURNERS. BUR the density of gas when arrived at the point where it has to he burnt) requires two volumes of pure oxy¬ gen for its complete combustion and conversion into carbonic acid and water. Atmospheric air con¬ tains, in its pure state, twenty per cent, of oxygen, — in populous towns less ; hut twenty per cent, may be taken as a fair average : 1 cubic foot of carburetted hydro¬ gen then requires for its proper combustion 10 cubic feet of air ; if less be admitted on to the flame, a quantity of free carbon will escape (from its not finding a proper vo¬ lume of oxygen for conversion into carbonic acid), and be deposited in the form of dense black smoke. When the flame from an Argand burner is turned up high, the air which rushes through the interior ring becomes decomposed before it can reach the air on the top of the flame, which consequently burns in one undivided mass, the gas being in part unconsumed, the products unconverted, and carbon deposited abundantly. If an excess of air is admitted, it would appear at first to be of no consequence, but it will be found that the quantity of nitrogen ac¬ companying this excess has a ten¬ dency to extinguish the flame, while it takes no part in the elective affi¬ nity constantly going on between the several elementary gases, viz. hydrogen, oxygen, and the vapour of carbon ; and also that the quan¬ tity of atmospheric air passing through the flame unchanged, tends to reduce the temperature below that necessary for ignition, and therefore to diminish the quantity of light. For the proper combus¬ tion of the gas, neither more nor less air than the exact quantity re¬ quired for the formation of carbonic acid and water can be admitted through the flame without being injurious. It is not possible practi¬ cally to regulate the supply of air to such a nicety : it is preferred | therefore to diminish the quantity of light by having a slight excess of air rather than to produce smoke by a deficiency, the former being unquestionably the least evil. Burnet (James), a landscape painter : died in 1816, aged 28 years. Burning-glass, a glass lens, which, being exposed directly to the sun, refracts the rays which fall upon it into a focus. Burning-house, the furnace in which tin ores are calcined, to sublime the sulphur from pyrites : the latter being thus decomposed, are more readily removed by washing. Burnisher, a tool used for smoothing and polishing a rough surface. A- gates, polishe^ steel, ivory, etc., are used for burnishing. Burnt Carmine is, according to its name, the carmine of cochineal par¬ tially charred till it resembles in colour the purple of gold, for the uses of w'hich in miniature and water painting it excels. Burnt Sienna earth is, as its name implies, the Terra di Sienna burnt, and is of an orange-russet colour. Burnt Umber, a pigment- obtained from a fossil substance, which w T hen burnt assumes a deeper and more russet hue: it contains manganese and iron, and is very drying in oil, in which it is employed as a dryer. It is a fine warm brown, and a good wmrking strong colour, of great use j| for the hair of the human head, and mixes finely with the warm shade. Burnt Verdigris is an olive-coloured oxide of copper deprived of acid. It dries well in oil, and is more durable, and in other respects an j improved and more eligible pig¬ ment than in its original state. Burre-stone, a mill-stone w r hich is almost pure silex: the best kind is of a wdiitish colour. BurrocJc, a small weir or dam, w'here wheels are laid in a river for catch¬ ing fish. Burrow, in mining, the heap or heaps of attle, deads, or earth (void of ore), which are raised out of a mine, 72 BYZANTINE ARCHITECTURE. BUR and commonly lie around the shafts ; any heap or hillock of deads or waste. Burr-pump, a bilge-pump worked by a bar of wood pulled up and down by a rope fastened by the middle. Bursa, a bag; a purse used in the middle ages for the purposes of a little college or hall for students. Bursar, one to whom a stipend is paid cut of a fund set apart for poor students ; the treasurer of a college. Bursary , the treasury of a college. Burthen, the weight or measure of capacity of a ship. Multiply the length of the keel, the inner mid¬ ship breadth, and the depth from the main deck, to the plank joining the keelson together; and the pro¬ duct, divided by 94, gives the ton¬ nage or burthen. Burton, a manor; a manor-house. Burton, in a ship, a small tackle of two single blocks, named from the inventor. Bush, in machinery, a piece of metal fitted into the plummer-block of a shaft in which the journal turns. The guide of a sliding-rod also bears the same name. Bush, a circular piece of iron or other metal, let into the sheaves of such blocks as have iron pins, to prevent their wearing. Bushel, a dry measure of 8 gallons or 4 pecks. Bush-harrow, an implement used in harrowing grass lands. Buskin, a high shoe or boot worn anciently, in tragedy, on the stage. Bushnell (David), A.M., of Saybrook, in Connecticut, in 1776 invented several machines for the annoyance of shipping: he destroyed a vessel in the charge of Commodore Sim- monds, whose report to the Admi¬ ralty was published. | Buss, a small sea-vessel used in the herring fishery. 1 Bust, in sculpture, the head, neck, and breast of human figure. Bustum, anciently a tomb. I But, the end of a plank where it unites with another. BYZ But-hinges, those employed in the hanging of doors, shutters, etc. Butmen cheeks, the two solid sides of a mortise varying in thickness. Butments, the supports on which the feet of arches stand. Butterfly-valve, the double valve of an air-pump bucket, consisting of two clack-valves, having the joints opposite and on each side of the pump-rod. Butteris, an instrument of steel set in a wooden handle, used by farriers for paring the hoof of a horse. Butternut-ivood is of large size, and is produced in New Brunswick. The propagation of this tree is very easy, either from the cuttings or from the nut. Buttery, a cellar in which butts of wine are kept; aplace for provisions. Buttock, the round part of a ship abaft, from the wing transom to the upper water-line, or lower down. Button (in smitherv), a brass knob of a lock serving to open or shut a door. Button (in carpentry), a piece of wood upon a nail, to keep a door close. Buttress, inGothic architectural struc¬ tures, a pilaster, pier, or masonry added to and standing out from the exterior of a wall. Buttresses are usually divided into several heights, each of which projects less from the wall as they ascend. Buttress, a piece of strong wall that stands on the outside of another wall, to support it. By, said of a vessel when her head is lower in the water than her stern; if her stern is lower in the water, she is hy the stern. Byard, a piece of leather across the breast, used by those who drag the sledges in coal-pits. Byzantine Architecture. About the year a.d. 328, Constantine, who had previously resided at Rome, commenced his new capital in the East, which was called after his name, and in May, 330, was so¬ lemnly dedicated to the Virgin Mary. He adorned it with so 73 CABBLING. CAB many stately edifices that it nearly equalled the ancient capital itself: he here built a cathedral dedicated to Santa Sophia,or tlieEternalWis- dom,and a church to the Apostles. This cathedral, having been twice destroyed by fire, was finally rebuilt about 532 a.d., by Justinian, who had invited the celebrated architect Anthemius to Constantinople for that purpose. It was completed in six years from the time of laying the first stone. The Emperor, in his admiration of this magnificent edifice, is said to have exclaimed, “ Ihave vanquished thee, 0 Solomon:” and with justice might he glorify himself, for the dome of St. Sophia is the largest in the world, and the more to be ad¬ mired in its construction from the lowness of the curvature. This church, after twelve centu¬ ries, remains the same, with the ex¬ ception of the mode of worship to which it is devoted. It still retains its former name, but the Maho¬ metans, instead of the Christians, possess it. This is the earliest Byzantine building extant, totally dissimilar in arrangement to the Christian churches in the empire. The plan of the interior is that of a Greek cross, the four arms of which are of equal length ; the cen¬ tral part is a square, the sides are about 115 feet in length. At each angle of the square a massive pier has been carried, 86 feet in height from the pavement, and four semi¬ circular arches stretch across the Cabbling. The process in the manu¬ facture of iron, which in Glouces¬ tershire is called ‘ scabbling,’ or, more correctly, ‘ cabbling,’ may be thus described. When the cast or pig-iron has been subjected to the influence of a refinery, the product is called ‘ Fineryit is then carried CAB intervalsoverthe sides of thesquare, and rest on the piers. The interior angles between the four piers are filled up in a concave form. At 145 feet from the ground is the level of the springing of the dome, w hich is 115 feet in diametdr; the form is a segment of a circle, and the height is equal to one-sixth of its diameter at the base. On both the eastern and western side of the square is a semicircular recess, with domes that rest against the main arches, and assist in resisting the lateral thrust. On the north and south sides of the square are vesti¬ bules forming a square on the plan. Above the vestibules are galleries appropriated to women during the performance of worship. The whole church is surrounded by cloisters, and enclosed by walls. The total cost of St. Sophia has been reckoned at the lowest com¬ putation to have exceeded one mil¬ lion pounds ; as before the building was four feet out of the ground, its cost had amounted to a sum equi¬ valent to £200,000 sterling. Besides this cathedral, Justinian is said to have built, at Constanti¬ nople, twenty-five churches to the honour of Christ, the Virgin, and the Saints; he also built a church to St. John at Ephesus, and another to the Virgin at Jerusalem: the bridges, hospitals, and aqueducts erected by this emperor were nu¬ merously distributed throughout the empire. Byzanteum artificium, mosaic-work. c. to the forge, and smelted in a fur¬ nace with charcoal: in a short time, a large ball,about 2Jcwt.,is formed by working with an iron bar; this ball is then taken to a large ham¬ mer, and beaten into a flat oval or oblong shape, from 2 to 4 inches in thickness: this is allowed to 74 CAB CALCULATING MACHINES. CAL cool, when ‘ cabbling ’ commences, which is simply breaking up this flat iron into small pieces. Men are especially allocated for this ope¬ ration, and are named ‘ cabblers.’ The pieces of iron obtained by cabbling are then heated in another furnace almost to fusion, hammered down into shape, and ultimately drawn out into bar-iron. Cabin, a room or apartment in a ship where any of the officers usually re¬ side, and also used in passenger ves¬ sels for the residence of passengers. Cabinet pictures, usually denominated so, are small valuable paintings from flie old masters, painted ou copper, panel, or canvas. Modern subjects, if painted small in size, should equally be called Cabinet. Cabinets, in Tudor times, were of massive proportions, carved in oak, ebony, walnut, and other woods, inlaid. Some of them answered the double purpose of depositories and cupboards for plate, from having drawers and recesses, or ambries, enclosed by doors; and broad shelves between the tiers of turned columns were conspicuous objects in these apartments. Cable, a thick stout rope, made of hemp, etc.,to keep a ship at anchor. Cable-moulding,& bead ortorus mould¬ ing, cut in imitation of the twisting of a rope, much used in the later period of the Norman style. Cabling, a round moulding, frequently used in the flutes of columns, pilas¬ ters, etc. Cadrnia, a stone, out of which brass is tried ; brass ore. Caduceus, an emblem or attribute of Mercury: a rod entwined by two winged serpents. Calatura (Greek), a branch of the fine arts, under which all sorts of or¬ namental work in metal, except ac¬ tual statues, appear to be included. Caementicius, built of unhewn stones ; large irregular masses laid together without mortar, having the inter¬ stices filled in with small chippings. Caen stone, a peculiar quality of stone used for building purposes, prin¬ cipally for Gothic structures ; it is taken from quarries in Normandy. CageworJc, the uppermost carved work of the hull of a ship. Caisson, a wooden frame or box with a flat bottom, made of strong timbers firmly connected together; used for laying the foundations of a bridge in situations where the coffer-dam cannot be adopted. Caisson, a name given to the sunk panels of various geometrical forms symmetrically disposed in flat or vaulted ceilings, or in soffits gene¬ rally. Cal, in Cornish mining, a kind of iron Gossan stone found in the bryle and backs of lodes, much of the colour of old iron ; reckoned a poor brood with tin. Calcar, a small oven or reverberatory furnace, in which the first calcina¬ tion of sand and potashes is made for turning them into frit, from which glass is ultimately made. Calcareous earth, the same as lime, and of which there are various combinations, as marble, limestone, marl, gypsum, etc. Calcatorium, among the Romans, a raised platform of masonry in the cellar attached to a vineyard. Calcination, the process of subjecting a body to the action of fire, to drive off the volatile parts, whereby it is reduced to a condition that it may be converted into a powder : thus marble is converted into lime by driving off tbe carbonic acid and water ; and gypsum, alum, borax, and other saline bodies are said to be calcined when they are deprived of their water of crystallization. Calcium, the metallic basis of lime. Calcography, writing, engraving, etc. Calculating machines are of early in¬ vention ; but recently Mr. Babbage has completed a calculating ma¬ chine surpassing all previous ones ; the machine accomplishes the ad¬ ditions of numbers by the move¬ ments of a number of cylinders having on the convex surface of e 2 75 CALORIC SHIP. CAL each the series of numbers 12 3 4 5 6 7 8 9 0; and the operations are of two kinds: by the first the additions are made, and by the second there is introduced the 1, which should be carried to the ten’s place every time that the sum of the two numbers is greater than 10, etc. Caldarium, the hot hath. The vase which supplied the hot bath was likewise so termed. According to Vitruvius, the thermal chamber in a set of baths. Calender, a mechanical engine for dressing and finishing cloths. Calends, in Roman antiquity, the first day of every month. Caliber or Caliper compasses; com¬ passes made with bowed or arched legs, for the purpose of taking the diameter of any round body. Caliber, an instrument used by car¬ penters, joiners, and bricklayers, to see whether their work be well squared. Calico, a cloth made from cotton¬ wool, like linens : the origin of the name is from Calicut, in India. Calico-printing, the art of applying coloured patterns on a white or coloured ground of linen or cotton. Calidnets, pipes or canals disposed along the walls of houses and apartments; used by the ancients for conveying heat to several re¬ mote parts of the house. Caligraphy, fair or good writing. Calin, a mineral, like lead and tin. Calk, a Cornish term for lime. Callipers, a species of compasses with legs of a circular form, used to take the thickness or diameter of work, either circular or flat; used also to take the interior size of holes. Callipers, in turning, compasses with each of the legs bent into the form of a curve, so that when shut the points are united ; and the curves, being equal and opposite, enclose a space. The use of the callipers is to try the work in the act of turn¬ ing, in order to ascertain the dia¬ meter or the diameters of the CAL various parts. As the points stand nearer together at the greatest required diameter than the parts of the legs above, the callipers are well adapted to the use intended. Callys or A7//a6'(Cornish),hard, smart; the most common and agreeable stratum in our mine country, usually called killas. Caloric, the matter and cause of heat. Caloric (Ericsson’s) ship has under¬ gone a great experiment in naviga¬ tion. Wise men have long pondered the idea which Captain Ericsson is working out patiently and hope¬ fully. The need of new motors has become more manifest with the advance of time and commercial prosperity. Electricity has been tried, and has not succeeded. Ca¬ loric was something never known in its best sense until now, and the credit is due to Captain Ericsson of directing attention to an old agent of which new applications 7uay produce the most remark¬ able results. The experiment now making is no ephemeral fancy, but is the work of a quarter of a century of mature reflection and diligent inquiry. The ingenious projector under whose auspices it is carried forward has devoted his best ener¬ gies to the task, and it will not fail through want of forecast, judg¬ ment, or ability. Calorific, in chemistry, the quality of producing heat. Calorimeter,an instrument to measure the heat given out by a body in cooling by the quantity of ice it melts. Calotte, a round cavity or depressure in form of a cap or cup. Calquing, the process of copying or transferring a drawing. It is ef¬ fected by rubbing over the back of the original with a fine powder of red chalk or black lead; the smeared side is then laid on a sheet of paper, and the lines of the drawing are traced by a blunt-pointed needle, which imprints them on the paper underneath. Another method is to 76 CAMBER-SLIP. CAL hold the drawing up to a window with a sheet of paper before it: the outlines will appear through, and may be penciled off without damage to the original. Calyon, flint or pebble stone, used in building walls, etc. Cam, in steam machinery, a plate with curved sides, triangular or other¬ wise, fixed upon a revolving shaft, for changing the uniform rotatory motion into an irregular rectilinear motion. It is sometimes used for moving the slide-valves. Camaieu, a term used in painting when there is only one colour, the light and shades being of gold, or on a golden and azure ground. It is chiefly used to represent basso- rilievo. Camber, the convexity of a beam upon the upper surface, in order that it may not become concave by its own weight, or by the binder it may have to sustain, in the course of time. Camber-beams, are those used in the flats of truncated roofs, and raised in the middle with an obtuse angle, for discharging the rain-water to¬ wards both sides of the roof. Camber-slip, a piece of wood, gene¬ rally about half an inch thick, with at least one curved edge rising about 1 inch in 6 feet, for drawing the soffit-lines of straight arches : when the other edge is curved, it rises only to about one-half of the other, viz. about half an inch in 6 feet, for the purpose of drawing the upper side of the arch so as to pre¬ vent it from becoming hollow by the settling of the bricks. The upper edge of the arch is not always cambered, some persons preferring it to be straight. The bricklayer is always provided with a camber- slip, which, being sufficiently long, answers to' many different widths of openings: when he has done drawing his arch, he gives the camber-slip to the carpenter, in order to form the centre to the required curve of the soffit. Cambering, a sea phrase, used when CAM a deck is higher in the middle than at the ends. Camel, the name of a machine used by the Dutch for carrying vessels heavily laden over the sand-banks in the Zuyder Zee. Camera (Greek), an arched or vaulted roof, covering, or ceiling, formed by circular bands or beams of wood, over the intervals of which a coating of lath and plaster was spread: they resembled, in their construc¬ tion, the hooped awnings now commonly in use. Camera-lucida, and Camera-obscura, (the light and dark chamber,) the names given to two methods, simi¬ lar in principle, of throwing images of external objects upon plane or curved surfaces, for the purpose of drawing or amusement: in the first contrivance there is no chamber; but as it was the last invented, and as its predecessor had been called the ‘camera-obscura,’ it was termed the ‘ camera-lucida.’ Camerated, a term applied to the roof of a church. Cameron (C.),architect; published in 1772 and 1775, editions of the work on the Baths of the Romans. Carnes, the slender rods of metal used by glaziers as turned lead; they are usually cast in lengths which measure 12 or 14 inches. Caminus, according to Pliny, a smelt¬ ing furnace. Campance or Campanula or Guitce, the drops of the Doric architrave. Campanile, from the Italian, a bell- tower, principally used for church purposes, but now sometimes for domestic edifices. Campanini, a species of marble taken out of the mountain of Carrara, in Tuscany ; so called because, when wrought, it imitates the sound of a bell. Campanologia, the art or science of ringing of bells. Campbell (C.), an architect of his period of some celebrity ; erected several of the large mansions of the nobility and gentry of this 77 CAM CANAL NAVIGATION. CAN country, and first published his great work, entitled ‘ Vitruvius Britannicus,’ in 1715. Camphor-wood is imported from Chi¬ na and the Indies in logs and planks of large size, and used in England for cabinet-work and turnery. Campus Martius, a district outside the walls of ancient Rome, between the Quirinal and Pincian Mounts and the Tiber, dedicated to Mars : there public exercises were per¬ formed, and the consuls and other magistrates elected : it was adorned with statues, columns, arches, etc., and much frequented by thecitizens. Camus de Mezieres (M. le), born at Paris in 1721, and died in 1789 : he was the architect of the Halle au Ble and other buildings, and the author of several valuable profes¬ sional works. Cam-wood, the best and hardest of the red dye-woods: it is brought from Africa, and used in ornamental and eccentric turnery. Can, a term used in Scotland for a chimney-pot. Canal of the larmier, in architecture, the hollowed plafond or soffit of a cornice, which makes the pendent mouchette. Canal of the volute, in the Ionic capital, is the face of the circum¬ volutions enclosed by a listel. Canal Navigation, or river and inland navigation, or internal communi¬ cation by water, terms severally expressed.—The origin of inland navigation is involved in great ob¬ scurity. The ancient inhabitants of every part of the globe wherewith history has made us acquainted, were alive to the benefits resulting from the adoption of inland navi¬ gation : in England, the first on record is the Caerdike, cut by the Romans. Subsequently, very many very important ones, particularly those by Brindlay, under the direc¬ tion of the celebrated Duke of Bridgewater; and as late as 1829, the science of canal engineering was in active operation. Canals in France for ‘ grande navigation’ are made 33 feet 4 inches wide upon the floor-line, and 49 feet 6 inches upon the water-line, by 5 feet 5 inches depth of water. The locks are 106 feet 8 inches long by about 17 feet wide; the towing-paths 13 feet wide. Canals for ‘petite navigation ’ are made only 33 feet 4 inches wide upon the water-line, and 22 feet on the floor, with a depth of water of 5 feet. The locks are 100 feet long by 9 feet 1 inch wide. Some of theFrench canals for steam navigation have locks from 26 to 40 feet wide, and of lengths between 150 and 233 feet in clear of gates.—In England, no very definite rule appears to be followed in fixing the dimensions of canals. Those executed for the internal important lines vary from 31 to 48 feet upon the water-line, with an average depth of about 5 feet. The locks are generally 70 feet in length by 14 feet 6 inches to 18 feet wide. Small canals, in the mining dis¬ tricts, have in some cases been executed with a width of not more than 16 feet on the water-line, and they range from that to 28 feet. The locks are made of the same length as for large canals, but of only half the width. Ship-canals have been made of much larger dimensions, such as the Caledonian Canal, which has in part 122 feet upon the water-line, with a depth of 20 feet. The Gloucester and Berkeley Canal has a water-line of 70 feet and a depth of 18 feet. The Thames and Medway had a width of 50 feet by a depth of 7 feet; the Ulverstone, 65 feet by 15 feet: the locks being in proportion to the size of the canals. In the United States the same irregularity occurs in the dimensions of canals as in our own country. Canal, an artificial watercourse for connecting rivers and lakes ; a navigable communication. Canalis, in Latin, a water-pipe or gutter; used in architecture for any 78 CANDLESTICKS. CAN channel, such as the flutings of columns ; the channel between the volutes of an Ionic column. Canary-wood, from South America, is a sound, light, orange-coloured wood, used for cabinet-work, mus¬ ketry, and turnery. Cancelli, among the Romans, iron gratings and trellis-work ; in mo¬ dern buildings, latticed windows made with cross-bars of wood, iron, lead, etc. Candela, a candle, made either of wax or tallow ; used generally by the Romans before the invention of lamps. Candelabrum, originally a candlestick, but afterwards used to support lamps. Candlemas, the popular name for the feast of the Purification of the Virgin Mary, February 2, derived from the lights which were then distributed and carried about in procession. Candlestick of gold {The) was made by Moses for the service of the Temple, and consisted wholly of pure gold: it had seven branches, upon the extremities of which were seven gold lamps, which were fed with pure olive oil, and lighted every evening by the priest on duty -. it was used in the holy place, and served to illumine the altar of incense and the table of shew- bread, which stood in the same chamber. Candlesticks. The magnificence of these articles was at first displayed in chapels and in domestic apart¬ ments, as banquets in early times were given by daylight. "VVe find them, however, of very costly de¬ scriptions. In Henry the Eighth’s temporary banqueting - room, at Greenwich, the “ candlestykes were of antyke worke, which bare little torchetts of white waxe: these candlestykes were polished lyke ambre.” Cangica-wood, from South America, is of a light and yellow-brown colour, used for cabinet-work and turnery. CAN Can-hooks, strings with flat hooks at each end, used for hoisting barrels or light casks. Canopy, a covering or hood, the en¬ riched projecting head to a niche or tabernacle. The tablet or drip¬ stone, whether straight or circular, over the heads of doors or windows, if enriched, is so called. Canopy, in Gothic architecture, an ornamental projection over doors, windows, etc. ; a covering over niches, tombs, etc. Cant, a term used among carpenters to express the cutting off the angle of a square. Canted, applied to a pillar or turret when the plan is of a polygonal form. Canterbury (John), born at Tewks¬ bury, was clerk of the works of King’s College Chapel, Cambridge, of which College he was a Fellow in 1,451. Canterbury (Michael of), erected in 1291-93, the Cross in Westcheap, London, which was the handsomest, except Charing, of all that were erected to the memory of Queen Eleanor. Canterii, beams of wood in the frame¬ work of a roof, extending from the ridge to the eaves, corresponding to the rafters of a modern roof. The word canterii was also applied to two inclining reeds fixed in the ground some distance asunder and meeting at the top, for the support of vines. Cantharus, a fountain or cistern in the atrium or court-yard before ancient churches, at which persons washed before they entered the sacred buildings. Canthus, in Greek and Latin, the tire of a wheel; a hoop of iron or bronze fastened on to the felloe, to preserve the wood from abra¬ sion. Cantilevers are horizontal rows of timbers, projecting at right angles from the naked part of a wall, for sustaining the eaves or othermould- ings. 79 CAN CAPITAL. CAP Cantling. The lower of two courses of burnt bricks, which are placed on the top of a clamp before fire is applied. Cant-moulding, a bevelled surface, neither perpendiculartothe horizon nor to the vertical surface to which it may be attached. Cantoned, in architecture^ when the corner of a building is adorned with a pilaster, an angular column, rustic quoins, or anything that projects beyond the wall. Cant-pieces, in ships, pieces of timber fastened to the angles of fishes and side-trees, to supply any part that may prove rotterv. Cant-timbers, in ship-building, those timbers or ribs of the ship which are situated afore or abaft, or at the two ends, where the ship grows narrower below. Cant-timber abaft, the chock upon which the spanker-boom rests when the sail is not set. Cantuar. The signature of the Arch¬ bishop of Canterbury, is thus abbreviated, the Christian name being usually prefixed. Canvas, the cloth of which the sails of ships are made. Caoutchouc, a substance produced by the siphonia elastica, the ficus elas- tica, and the urceola elastica, and many other American and Asiatic trees. It is often termed Indian- rubber, from its use in removing pencil traces from paper. There are various chemical properties which render caoutchouc valuable in the arts, but elasticity and impervious¬ ness to water are those for which it is most prized. It is worked into a great variety of useful things for dress and for domestic purposes. Cap, a thick, strong block of wood, with two holes through it, one square and the other round, used in ship-building to confine together the head of a mast and the lower part of that next above it. Capacity, the same in sense as content or volume in pure mathematics. In physics it generally signifies the power of holding or retaining : thus we speak of the capacity of a body for heat, etc. Capel, in mining, a stone composed of quartz, schorl, and hornblende, usually occurring in one or both walls of a lode, and more frequently accompanying tin than copper ores. Capillary attraction and repulsion. These names have been given to the properties of matter which cause the ascent above or descent below the level of the surrounding fluid which takes place when a tube of small diameter is dipped into water, mercury, etc. Capital, in architecture, the head or uppermost part of a column or pi¬ laster. The capitals of the columns constitute the principal and most obvious indicia! mark of the re¬ spective orders. For those of each of the three classes or orders a cer¬ tain character conformable with the rest of the order is to be observed ; but that attended to, further re¬ striction is unnecessary. Between several examples, all decidedly re¬ ferable to one and the same order, very great special differences occur, and there might easily he a very great many more. Although the capital itself is indispensable, it is so only aesthetically, and not out of positive necessity. The necessity is only artistic: decoration of the kind there must be, but the express mode of it is one of those matters which should be left to design, to which it properly belongs. Capitals are just as legitimate subjects for the exercise of taste and invention as anything else in decorative de¬ sign. The capital is only an orna¬ mental head to the column, and therefore admits of being as freely designed as any other piece of orna¬ ment, on the conditions of its being accordant in character with the rest of the order, and of forming an agreeable transition from the shaft of the column to the architrave. Capitolium, a temple or citadel at Rome, on the Tarpeian rock: it was 80 CAP finished by Tarquinius Superbus, and consecrated by the consul M. Horatius,—was burnt in the time of Marius, and rebuilt by Sylla,— destroyed a second and a third time in the troubles under Vitellius and Yespasian, and lastly raised again byDomitian. Its name was derived from the discovery of the head of Tolius, during the excavation of the earth for the foundation. Q. Catulus consecrated it to Jupiter Capitolinus, and covered it with gilded brass tiles. The steep ascent of the rock was mounted by 100 steps on the side of the forum. In the temple were statues of gold and silver, vessels of those metals and of crystal, and 3000 brass tables, on which the Roman laws were engraved. Caple (in Cornwall) stone is some¬ thing like limestone, but will not burn. The walls of most lodes are of this kind, and therefore it is common to call a lode by the name of its caple: those veins which abound with it are termed caples or caple-lodes. Capreoli, the pieces of timber on a roof which serve to uphold the axes or principals. A fork inclined so as to afford support to anything was formerly called a Capreolus. Capsa or Capsula, a box for holding books among the Romans: these boxes were usually made of beech wood, and were cylindrical in form. Capsize , to overturn. Capstan , in naval architecture, a strong massive piece of timber let down through the decks of a ship, and resting its foot or axis, which is shod with iron, in an iron socket, called a saucer, fixed on a wooden block or standard, called the step, resting on the beams. \Captain, in mining, an experienced I miner ; one who directs and over- ; sees the workmen and business of a mine. I Caracal, a term sometimes used for a staircase in a helix or spiral form. Caradoc formation, the uppermost of CAR the two great divisions of the lower Silurian strata of Murchison, seen principally in Shropshire, Worces¬ tershire, Somersetshire, etc., and on the eastern borders of Wales. Caravanserai, a building in the East, expressed in our version of the Scripture by the term Inn; in Turkey it is understood to be a place of accommodation for strangers and travellers : they are built at proper distances through the roads of the Turkish dominions, and afford the indigent and weary traveller an asylum from the in¬ clemency of the weather. Carbon, a non-metallic elementary solid body, which is widely diffused throughout nature. The purest and at the same time the rarest formed w hich it occurs is that of the dia¬ mond ; the more common states in which it is met with are those of anthracite, graphite, and coal: an¬ other form is that of charcoal. Carbonate, a salt composed of car¬ bonic acid and a base. The chief varieties are described under their alkaline, earthy, and metallic bases. Carburet, a compound of carbon with nitrogen, metals, etc. Carcase {The) of a building is the naked w'alls and the rough timber- work of the flooring and quarter partitions, before the building is plastered or the floors laid. Carcase-roofing, that which supports the covering by a grated frame of timber-work. Career, a prison or gaol. The Roman prisons were divided into three stories, one above the other, each of which was appropriated to dis¬ tinct purposes. Card-making machine, an arrange¬ ment of wires used in the cotton manufacture, for disentangling the fibres of cotton preparatory to spinning. Cardo, a pivot and socket, an appa¬ ratus by means of which the doors of the ancients were fixed in their places, and made to revolve in opening and shutting. CARAVANSERAI. 81 CARLISLE TABLES. CAR Careening, the operation of heaving a ship down on one side by the application of a strong purchase to her masts, which are properly sup¬ ported for the occasion to prevent their breaking w T ith so great a strain, and by which means, one side of the bottom being elevated above the surface of the water, it may be cleansed or repaired. Carina, according to Cicero, the keel or lowest piece of timber in the framew'ork of a ship. Carlings, short pieces of timber rang¬ ing fore and aft from one deck- beam to another, into wdiich their ends are mortised : they are used to sustain and fortify the smaller beams of the ship. Carlisle Tables, so called from the more recent mode of making cal¬ culations of the value of annuities on lives, based on the average du¬ ration of human life, as taken at Carlisle, in Cumberland.. The value of a life annuity depends upon the manner in which it is presumed a large number of persons, similarly situated with the buyer, would die off successively. Various tables of these decrements of life, as they are called, have been constructed from observations made among different classes of lives. Some make the mortality greater than others ; and, of course, tables which give a large mortality, give the value of the annuity smaller than those which suppose men to live longer. Those who buy annuities would therefore be glad to be rated according to tables of high mor¬ tality, or low expectation of life; while those who sell them would prefer receiving the price indicated by tables which give a lower rate of mortality. Hence arise bar¬ gains or stipulations according to either the Northampton or Carlisle tabulated rating of the duration of life. In assurances the reverse is the case : the shorter the time which a man is supposed to live, the more must he pay the office, CAR that the latter may at his death have accumulated wherewithal to pay the amount. The Northamp¬ ton tables, formed by Dr. Price, from observations of burials at Northampton, as compared with all other tables of authority, give too high a mortality at all the younger and middle ages of life, and, consequently, too low a value of the annuity. The Carlisle tables, formed by Mr. Milne, give much less mortality than most of the old tables, and therefore a higher value of the annuities: they have been proved to represent the actual state of life among the middle classes. Carlovingian Architecture. French authors establish two epochs of art, under the terms Merovingian (from Clovis to Pepin, 481-751) and Car¬ lovingian (from Pepin to Hugh Capet, 751-987). Carmine {colour), a name originally given only to fine specimens of the tinctures of kermes and cochineal, and denoting generally at present any pigment which resembles them in beauty, richness of colour, and fineness of texture : hence we hear of blue aud other coloured car¬ mines, though the term is princi¬ pally confined to the crimson and scarlet colours produced from co¬ chineal by the agency of tin. Cam, in Cornish mining, a rock; a heap of rocks ; a high rock. Carnagioni (of the Italians), a colour which differs from terra puzzuoli in its hue ; in which respect, other variations and denominations are produced by dressing and com¬ pounding. Carol, a small closet or enclosure to sit and read in. Carpenter's square : the stock and blade are formed, in one piece, of plate-iron, and the instrument is thus constructed :—one leg is 18 inches in length, numbered from the exterior angle ; the bottoms of the figures are adjacent to the in¬ terior edge of the square, and con- 82 CARPENTRY. CAR sequently their tops to the exterior edge : the other leg is 12 inches in length, and numbered from the extremity towards the angle ; the figures are read from the internal angle, as in the other side; and each of the legs is about an inch broad. It is not only used as a square, but also as a level, and as a rule : its application as a square and as a rule is so easy as not to require any example; but its use as a level, in taking angles, may be thus illustrated : suppose it were required to take the angle which the heel of a rafter makes with the back,—apply the end of the short leg of the square to the heel-point of the rafter, and the edge of the square level across the plate; ex¬ tend a line from the ridge to the heel-point, and where this line cuts the perpendicular leg of the square, mark the inches : this will show how far it deviates from the square in 12 inches. Carpenter’s tools : the principal tools used in the rougher operations of carpentry are the axe, the adze, the chisel, the saw, the mortise and tenon-gauge, the square, the plumb-rule, the level, the auger, the crow, and the draw-bore-pin, or hook-pin, for draw-boring. Carpentry is the art of combining pieces of timber for the support of any considerable weight or pres¬ sure. The theory of carpentry is founded on two distinct branches of mechanical science : the one in¬ forms us how strains are propagated through a system of framing; the other, how to proportion the re¬ sistance of its parts, so that all may be sufficiently strong to resist the strains to which they are exposed. The cfne determines the stability of position, the other the stability of resistance. Each of these may be considered in the most simple manner the subject admits of, with the addition of rules and practical remarks. CAR Timber is wrought into various forms according to the principles of geometry ; and these forms are to be preserved in their original shape only by adjusting the stress and strain according to the laws of mechanics. Hence the importance of studying both these sciences is evident, and particularly the latter ; for unless the stress and strain be accurately adjusted, the most careful attention to geometri¬ cal rules, and the most skilful work¬ manship, will be exerted in vain. If, for instance, the centre of an arch were to be drawn and worked ever so truly to the curve required, what would it avail if the centre changed its form with every course of stone laid upon it ? And it must be remarked, that this is not an imaginary case, but one that has frequently happened ; and not only to men ignorant of mechanics, hut to some of the most celebrated engineers that France ever pro¬ duced. The engineers of our own coun¬ try have been more successful, having succeeded in gradually in¬ troducing a better principle of con¬ structing centres than our neigh¬ bours. The greatest defect of the English centres is now an excess of strength, which, on principles of economy, it would be desirable to avoid in erections for temporary purposes. Carpentry , in civil architecture, is the art of employing timber in the construction of buildings. The first operation of dividing a piece of timber into scantlings, or boards, by means of the pit-saw, belongs to sawing, and is previous to anything done in carpentry. The tools employed by the carpenter are a ripping-saw, a hand-saw, an axe, an adze, a socket-chisel, a firmer-chisel, a rip¬ ping chisel, an auger, a gimlet, a hammer, a mallet, a pair of pincers, and sometimes planes; but as these are not necessarily used, they are 83 CARVING. CAR described under the head of joi¬ nery, in which they are absolutely necessary. Carr (John), born 1723, at Horbury, near Wakefield, in Yorkshire, com¬ menced his career as a working mason; afterwards settling in York as an architect,in 1750,he executed many fine and expensive buildings ; died in 1807. Carrara marble , a species of white marble : it is distinguished from the Parian or statuary marble b,y being harder and less bright. It takes its name from Carrara, in Italy. Carrel, a pew, closet, or desk, with a seat placed under a window, where the monks were engaged in copying writings. Carriage of a stair, the timber which supports the steps. Carrick-bend, a kind of knot. Car- rick-bitts are the windlass-bitts. Carrier, the piece of iron which is fixed by a set-screw on the end of a shaft or spindle to be turned in a lathe, to carry it round by the action of the driver of the centre chuck. Carry away, a sea-term, to break a spar or part a rope. Carthusian buildings, Charter-house. The characteristic features of these buildings are austere, and to the Benedictine rule. The monas¬ teries of this order had generally two courts : the smaller, next the entrance, contained the priorial residence and the buildings allot¬ ted to secular purposes. Females were not only excluded from the court, but from the church. Cartoon, a distemper-coloured draw¬ ing, made on paper, linen, parch¬ ment, etc., of the exact pattern of a design intended to be executed either in tapestry, mosaics, or on glass : such are Raphael’s divine pictures in Hampton Court Pa¬ lace. Cartoon, in painting, a design drawn on strong paper, sometimes after¬ wards calqued through, and trans¬ CAR ferred on the fresh plaster of a wall, to be painted in fresco. Cartouche, the same as modillior., except that it is exclusively used to signify the blocks or modillions on the eaves of a house. Cartouche, an ornament representing a scroll of paper. Carucru, or Chica, a new pigment, of a soft powdery texture and rich morone colour, first brought from South America by Lieut. Mawe. Carving and inlaying of woods had become pretty general at the latter end of the sixteenth century. “ At Hardwick, in Derbyshire (1570), the wood-work, in several of the principal apartments, is oak, inlaid with ebony ornaments on the panels and stiles. The doors and shutters of ‘ Mary Queen of Scot’s room,’ as it is called, are framed in panels of light wood, inlaid with profiles of the Caesars, and other enrichments; the stiles, of darker coloured oak. In the state¬ room, the walls are divided, at about half the height, by a string¬ ing, the upper part filled with landscapes, figures, and animals, relieved in plaster, and painted in their proper colours on white ground; and the lower division hung with tapestry. The chimney front is entirely occupied by a large armorial compartment, re¬ lieved in plaster and emblazoned.” Cary at es or Caryatides (Greek), fi¬ gures used instead of columns, employed in architecture to repre¬ sent the portraiture of the defeated Persians after the subjugation of the Caryatae. The male figures are denominated Persians, Telamones, or Atlantides; the female, Caryans or Caryatides. Caryatides, anthropostylar pillars or human figures (usually female ones) employed instead of columns to support an entablature. Such fi¬ gures ought always to be perfectly free from all attitudinizing, and to appear to support their burden without any effort. Some very 81 CASTING. CAS matter-of-fact critics object to ca¬ ryatides as being at the best only beautiful absurdities ; as if statues so applied were particularly liable to be mistaken for living persons subjected to a more severe punish¬ ment than that of being posted up in a niche, or on the top of a building. Casa, according to Vitruvius, a cot¬ tage ; a small country-house. Cased tin, in Cornish mining, that which is re-framed by the gentlest current of water, and prevented from running off the frame by turf placed at the bottom. Case-hardening. The hardness and polish of steel may be united, in a certain degree, with the firmness and cheapness of malleable iron, by what is called case-hardening, an operation much practised and of considerable use. Casement, a frame enclosing part of the glazing of a window, with hinges to open and shut; also an early English name for a deep hollow moulding. Casement, the same as ‘ scotia,’ the name of a hollowed moulding. Casements, sashes or glass frames opening on hinges and revolving upon one of the vertical edges. Cases, in Cornwall, very small fissures in the strata of the earth, through which small streams of water flow when they are opened by the work¬ ing underground, greatly to the hindrance of the workmen. Casing of timber-work, the plastering a house all over on the outside with mortar and then striking it wet by a ruler with the corner of a trowel, or the like instrument, to make it resemble the joints of freestone, by which means the whole house appears as if built thereof. Casino. The Italian name used at first for a small house, afterwards a pleasure-house in a garden, and then for a place of relaxation in town. Cassel earth, or Castle earth, an ochreous pigment of a brown co- _ CAS lour, more inclined to the russet hue. Cassia Fistula is a native vegetable pigment, though it is more com¬ monly used as a medicinal drug. Cast, to pay a vessel’s head off, in getting under way, on the tack she is to sail upon. Cast after cast, in Cornwall, is throw¬ ing up of tin stuff, etc., from one stage of boards to another, each cast about 5 or 6 feet high. Castella, square towers in the ce¬ lebrated Roman wall of Severus, which was raised to separate Eng¬ land from Scotland. Castellated, built in imitation of an ancient castle. Castellum, the receptacle in which the water was collected and heated for the public baths of the Romans; a castle. Casting, among sculptors, the taking casts of impressions of figures, busts, medals, leaves, etc. Casting of draperies: by this term is implied the distribution of the folds, and draperies are said to be well cast when the folds are dis¬ tributed in such a manner as to appear rather the result of mere chance than of art, study, or labour. In that manner or style of painting, which is called the grand, the folds of the draperies should be great, and as few as possible, because their rich simplicity is more sus¬ ceptible of great lights; but it is an error to design draperies too heavy and cumbersome, for they ought to be suitable to the figures, with a combination of ease and grandeur. Order, contrast, and a variety of stuffs and folds, consti¬ tute the elegance of draperies; and diversity of colours in these stuffs contributes extremely to the har¬ mony of the whole in historic com¬ positions. Casting or Warping, in joinery, is the bending of the surfaces of a piece of wood from their original posi¬ tion, either by the weight of the wood or by an unequal exposure to 85 CAS CASTLE. CAT the weather, or by the unequal tex¬ ture of the wood. Cast-iron framing, for mill-work, possesses great superiority over that of timber, for constructing the framing. It is not only much more durable, but, from the uni¬ formity of its texture, may be con¬ verted into any shape, so as to give it great advantage in arranging the materials with respect to strength, and proportioning it to the stress it has to sustain. Cast-iron shoes for roofs. A practice has been recently introduced into the construction of roofs having the beams of wood, of protecting their extremities from the damp and consequent decay to which they are liable, by resting imme¬ diately in contact with the brick or stone work of the walls of the building. This is effected by what the workmen call cast-iron shoes, which are attached to the ends of the tie-beams by means of bolts, nuts, etc. The iron shoe itself, of course, takes various forms, according to circumstances and the situation where it is introduced, and the particular views of the architect who employs it. In cases where, from the nature of the work carried on, every part is exposed to great heat and mois¬ ture, the defence afforded by such an attachment is of great import¬ ance ; the wood, unless thus pro¬ tected, being of course very liable to decay in those parts where damp and moisture might accumulate. Castle , a fortified and strong man¬ sion, situated and constructed and arranged for the purpose of pro¬ tecting its inmates against the as¬ saults of enemies ; in modern use, domestic residences of the nobi¬ lity and gentry, without the neces¬ sity of being garrisoned by armed men. Cat, the tackle used to hoist the an¬ chor up to the cat-head. Catacombs, subterraneous vaults or excavations used as burying-places. Catadrome, a tilt-yard, or place where horses run for prizes ; also an en¬ gine like a crane, used by builders to draw up or let down any weight. Catafalco, a decoration of sculpture, painting, etc., raised on a timber scaffold, to show a coffin or tomb in a funeral solemnity. Catagraph, the first draught of a picture. Catamaran, a name given both in the East and West Indies to some kinds of rafts, which are used in short navigations along the sea-shore. Cataract, a contrivance applied to Cornish engines for regulating the number of strokes per minute : it consists of a small pump fixed on a cistern; the piston is raised at each stroke of the engine by a tappet on the plug-rod, and the water rises into the cylinder of the pump ; it is then forced through a cock by means of counterw eights attached to a cross-head on the pump piston-rod : when the water has been forced back into the cistern, a series of levers, acting on a rising rod, loosen catches which allow r weights to act, by means of levers, to open or shut the steam, equilibrium, and exhaust valves. Cataractes, a cataract, cascade, or sudden fall of water from a higher to a lower level ; according to Pliny, a sluice, flood-gate, or lock in a river. Catch, a contrivance in machinery, acting on the principle of a latch. Catenary, in the higher geometry, a mechanical curve which a chain or rope forms itself into by its own weight, when hung freely between two points of suspension, whether these points be in the same hori¬ zontal plane or not. Catgut, in turnery, the string which connects the fly and the mandril. Cat-harpin, an iron leg used to con¬ fine the upper part of the rigging to the mast. Catharpings, small ropes in a ship, running in little blocks, from one 8G CATHEDRALS. CAT side of the shroud to another, near the deck. Cat-head, in naval architecture, a large square piece of timber, one end of which is fastened upon the forecastle and the other end pro¬ jects without the bow, so as to keep the anchor clear of the ship when it is being drawn up by a tackle. Cathedra, according to Horace, a chair without arms; according to Juve¬ nal, a chair with a long deep seat. Cathedral, the principal church of a diocese, in which the bishop’s throne is placed. Very few of the Gothic cathe¬ drals on the Continent have the tower or spire springing from the centre of the cross, and resting on four pillars, to balance the thrusts of the ranges of arches centering there ; nor have those of Strasburg, Ulm, Vienna, Orleans, or Antwerp. “ The distribution of light in a Gothic cathedral is ad¬ mirably adapted to the grandeur of the edifice, and produces that effect which a painter aims at in his picture. At the entrance at the west,thewindow being placed high, there is a low-toned light on the lower part of the pillars, and a shadow on the pavement, which, as we walk up the nave, graduates into light from the choir. The east window, always the broadest and the highest, pours in a greater body of light than is to be found in any other kind of building. The altar, rather in shadow, surrounded by this strong light, gives additional effect by contrast. The light from the transept windows is softened down by painted glass. The small windows, placed high along the aisles, enlighten their roofs, but the lower part of the pillars and floor remain in shadow.” Cathedral (the very ancient)of Usum- bar and other Armenian churches in Georgia have an arcade sur¬ rounding the outside of the build¬ ing, of which the arches are in the flattened Gothic style: the same CAU form prevails in the windows, doors, etc., in the body of the church. These structures are of an earlier date than any Gothic architecture in Italy. Catherine-wheel, in architecture, an ornament that occurs in the upper part of the north and south tran¬ septs of ancient cathedrals. Catherwood (Frederick), architect, born in London 1799: his travels were extensive; had much to do both in North and South America; was lost in the Arctic in 1854. Cathetus. The eye of the volute is so termed because its position is determined, in an Ionic or voluted capital, by a line let down from the point in which the volute generates. Cathhnia, a subterraneous mineral vein, out of which gold and silver are dug. Cat's:paw, a hitch made in a rope. Cauliculus, the volute or twist under the flower in the Corinthian capital. Caulking, in naval architecture, the art of driving a quantity of oakum, i.e. old ropes untwisted and soft¬ ened, into the seams of the planks, to keep out the water. Caunter and Caunting, in Cornish mining, Contra: when two lodes run across, the one, with respect to the other, is called a counter or contra lode. Cans (S. de), born in France, was drawing-master to Henry Prince of Wales : he published several scien¬ tific works. Died in 1614. Caus (J. de), of Dieppe, brother of the above, hydraulic engineer. Causeway, a carriage-road. Cautions in Architectural Construc¬ tion .— UNION OF NEW AND OI.D WORK. In attaching any new work to a building, every allowance must be made for the sinking of the footings under pressure, and for the settle¬ ment of the masonry into itself. Thus, while it is necessary that a vertical groove, or indent, be made in the old work, to receive a cor- 87 CAU CAUTIONS IN CAU responding piece of the new, it is still more essential that a freedom for the downward motion of the latter should he secured: otherwise, if it he tightly toothed and bonded into the old work, the result illus¬ trated in the annexed sketch may he anticipated. UNION OF ASHLAR FACING WITH BRICK OR RUBBLE BACKING. The same caution required in the latter case must be here equally observed. The backing (composed of small material and much mor¬ tar) will settle more than the face; and the latter will consequently bulge. This is easily remedied by computing, and allowing for, the difference of settlement; and by a due regard to the occasional bond¬ ing of the ashlar, so as to make the wall one substance, instead of two differently conditioned. The preceding sketch illustrates the consequence of weight pressing upon unbonded ashlar and upon yielding rubble. INVERTED ARCHES. Inverted arches must be used cautiously. Here is an instance, in which the points a and a were prevented by the inverted arch from sinking with the points b b, which latter sunk the more from the pressure of the arch c in the direction of the dotted lines. It is not uncommon for the young architect to affect precautionary science, without a due considera¬ tion of the peculiar circumstances of his case. DRAINAGE, ETC. Always endeavour, if possible, to get your water-closet cess-pit out¬ side the building, so that it may be approached for cleansing with¬ out disturbing the interior. Be careful in the efficient use of dip- draps to prevent the ascent of rats from the outer sewer into the I drains which are under the floors of the house. Rats are destructive in their operations, and if they die in the drain, prove, for a length of time, an unbearable nuisance. Drains may serve every purpose of carrying off soil and water; but the slightest opening in their upper part will allow the escape of effluvia into the space under the ground J flooring, and thence into the rooms, unless that space be thoroughly ventilated with grated openings, allowing a thorough draught,—or, 88 CAU CONSTRUCTION. CAU at least, a free ingress of fresh air, and equal egress of foul. In the application of covered dry areas round the excavated basements of buildings, on no account omit their entire ventilation. If this be not attended to, the main walling, which they are intended to preserve from damp, may remain even more continually moist than if in imme¬ diate connection with the natural ground. Moisture frequently rises up the walling from below its foun¬ dation, and, exuding from the face of the masonry, remains confined, unless it evaporate and escape. Without means to this end, a co¬ vered area will be merely a recep¬ tacle for damp, and may keep the masonry continually wet, even when the ground outside is perfectly dry. Be especially cautious that the water from the rain-pipes of the roofs and fiats be not conducted by them into the foundations. FIRE OPENINGS. It will save much subsequent trouble and disturbance of masonry, to be assured as to the size and character of the stoves, grates, ranges, etc., which the proprietor will employ. In the kitchen and cooking-rooms, especially, precau¬ tionary care should be taken in suiting the openings to the intended apparatus. Do not forget to be prepared for a smoke-jack, etc. DWARF WALLS. In constructing these, do not omit the holes, etc., necessary for under-floor ventilation. PAVING. Be careful that the bottom, on which fine paving is laid, be dry and free from staining material. Common lime mortar is often in¬ jurious to pavements. Portland paving is especially liable to be disfigured by it. WROUGHT STONE-WORK. In putting wrought stone-work together, iron is to be avoided as the certain cause of its subsequent destruction. The stone cornices, architraves, and dressings of many a noble mansion have been brought into premature ruin by the con¬ traction and expansion of iron under the effects of cold and heat. But there are careless contractors who will allow their Corinthian capitals and fluted shafts to be ruined, even before the entablature surmounts them; and the young architect will not, therefore, omit to insert a clause in his specifica¬ tion (and to be peremptory in its enforcement), that all cut stone¬ work be securely preserved, during the progress of the building, with wood casing. It is surprising how grossly indifferent each class of artificers is to the work of the others. It is still more surprising to observe how frequently they seem indifferent to the preserva¬ tion of their own. SLATING. Get rid of the masons and plas¬ terers and plumbers before your slaters begin. The injury done to slating by the afterwork of chim¬ ney-tops, etc., is much to be dreaded. The cementitious ‘ stop¬ ping ’ to a roof will not be effi¬ ciently done without close super¬ vision : the ridge, hip, and valley courses will not be properly formed of large cut slates,—nor will every slate have its two nails, unless the architect see to it. PLASTERING. Clear may be your specification in forbidding salt sand, but, if your work be carried on in the vicinity of any estuary, the chances are (unless you be deemed cruelly strict) that the surface of your in¬ ternal walls will vary with the weather, from damp to dry, like a seaweed, and throw out salt in abundance. BEAMS, JOISTS, AND OTHER TIMBERS. LINTELS, BOND, PARTITIONS. It is the office of walls to carry 89 CAU CAUTIONS IN CAU beams, etc.; and that of beams to stay the walls from falling out¬ wards or inwards: but it is the duty of architects to see that the wood-work which supplants ma¬ sonry does not weaken the latter; i. e. that the ends of timbers in¬ serted into walls may not, by com¬ pression or decay, leave the su¬ perincumbent masonry to loosen downwards. Thus, the beam a, though entering only a portion of the wall,presses uponthe thorough- stone e, which throws the weight upon the whole wall, and has, by means of an iron plate c, a hold to secure its perpendicularity. The cover-stone c presses on the surface of the timber to confirm its secu¬ rity : but should the timber rot, the cover-stone will not sink, be¬ cause sustained by the side-stones d d. To prevent rot, the backing and side-stones are left free of the timber, so that air may traverse round it. The habit of plac¬ ing the ends of beams on a template, as g, is bad. The only jus¬ tification of the employment of wood, so built into the walls, is when it forms a continuous plate, that it may act as a bond to pre¬ serve the perfect horizontal level of joists, which, however, should ex¬ L- .] -——-^ Psl EE5 j tend a little beyond the plate, so as to have a bearing also on the solid of the wall. Careful inspection 90 will then so manage the construc¬ tion of the wall in this part, as to leave it but little weakened by the air-hollows required for the plate and joists : unless, indeed, it be very thin,—as only one brick, for instance,—when no law of common sense can justify the use of conti¬ nuous bond. Where joists uninter¬ ruptedly cross a thin wall, which is to support another story of ma¬ sonry, let there only be one plate, thin, and on its edge, in the centre of the wall, so that at least a brick on edge may be placed on each side of it, to fill up the intervals between the joists, and give solid support to the superincumbent masonry. On no account let the upper part of the wall be separated from the lower by a mere layer of perishable wood, or supported by a range of joists on their edge. It has often been seen that iron hoop¬ ing should be more used than it is as the internal bonding of walls. At the same time it must be re¬ membered that bond timbering is necessary, at intervals, to receive the nails of the battening. When, however, the wall is thin, it may be imperative to avoid its use, employing old oak bats for that purpose. In short, let it be the care of the young architect, so to contrive the union of his masonry and carpentry, as that the entire removal of the latter may leave the CONSTRUCTION. CAU former secure in its own strength. In the use of lintels especially, he should be cautions. They are use¬ ful as bonds to unite the tops of piers, and as means for the fixing of the joinery; but they ought never to be trusted to as a lasting support of masonry,—-that support being always really afforded by the relieving segment arch above the lintel. A bressummer may be termed a large lintel; and by its adoption here, at least, the support of the masonry is truly intended. The use of the bressummer, in shop¬ front openings, is an evil necessity to which an architect must often submit; and all that he can do, is to make the best of a bad job, by wrought-iron trussing, which will at least give adequate strength , though it may not ensure perma¬ nent durability. If time spare it, fire may destroy it; and the latter evil is not to be met even by iron, which, if wrought, will bend,—if cast, will crack,—with heat. Let the arch, then, or some modifica¬ tion of it, be always used, if pos¬ sible. Partitions of wood should not be left to the sagacity of the carpenter. Under all circumstances where they have to support themselves over I voids, or to bear, or participate in the bearing of, a pressure from above, they should be considered by the architect in his specifica¬ tion, and carefully studied in making the working drawings. It CAU is not enough merely to say, that “ they are to be trussed so as to pre¬ vent any injury to ceilings by their own pressure;” marginal sketches should be made, showing the dis¬ position of the skeleton framing, with whatever iron-work is neces¬ sary to its security. See, for in¬ stance, what a carpenter may do, unless well directed : a roof c, bearing partly on the partition a, when it should have borne only on the walls ; and, instead of distress¬ ing the partition, should have rather held it suspended : the par¬ tition a bearing down with its own weight, and that of the roof, on the floor b, instead of being so truss-framed in its length as to leave the floor unconscious of its existence. No ignorance in the young architect is presumed as to the manner of doing these things ; he is merely admonished not to imagine that they are so obvious as to be done without his guidance. In the framing of roofs, give a maximum strength to the purlins : the undulating surface of a weakly- purlined roof will soon proclaim its defect in this particular. The position of the principals should not be observable from without. FLOORS ; SIMPLE AND FRAMED, ETC. For permanent and uniform strength, there is no floor so good as one composed of simple joists, stiffened by cross-bonding : but, in very large rooms, there is more economy in the compound floor of binders and joists, or of joists, binders, and girders. There may be particular reasons for girders, etc.; as, when the weight of the floor has to be thrown upon 91 CAUTIONS. CAU piers, and not oh a continuous wall of uniform strength : but the usual motive to the use of the compound floor, in rooms which exceed 18 or 20 feet in width, is a legitimate economy of materials. It is only necessary to caution the young practitioner on the necessity of considering, that girders have to perform the duty of cross-walls; that they should be trussed to prevent their ‘ sagging ’ even with their own weight; that their scant¬ ling should allow for the weakening effect of the cuttings made into their substance to receive the tim¬ bers they support; that their truss¬ es should be wholly of iron (and not partially of oak); and, espe¬ cially, that the end of each girder, instead of being notched on perish¬ able templates of wood, and closely surrounded with mortar and ma¬ sonry, should be housed in a cavity with an iron holding-plate ; or inserted into a cast-iron boxing, notched into a thorough - stone, leaving a space (however small) for the air to circulate about it, and prevent rot. The failure of a girder sometimes involves the failure of all the rest of the floor : and, though all timbers inserted in masonry should have a more careful regard to their preservation from decay than it is usual to be¬ stow, it will be readily admitted, that too much care cannot be given to those leading bearing timbers, without the permanent duration of which the durability of the large remainder is of no avail. ROOFS. The same remarks, applying to CAU the extremities of girders, apply also to tie-beams. CEILINGS. To procure a good ceiling in single-joist floors it is necessary there should be ceiling-joists cross¬ ing below the others : and it is a question whether the ceiling-joists, under double-framed floors, instead of being chase-mortised into the binders, should not be in unbroken lengths nailed under the binders. Where the ceiling-joists (as under roofs) are likely to be trodden upon, they must be well secured. SOUND BOARDING. Always consider whether the occupants of any particular room will be annoyed by noises from the rooms below or above. Sound boarding and pugging considerably increase the weight of the floor, the scantling of whose timbers should therefore be thought upon. Watercloset partitions should be well pugged. MICE IN PARTITIONS AND SKIRT¬ INGS. The space behind the skirtings is often a thoroughfare for mice, which also contrive to travel from floor to floor in the hollows of the quarter- partitions, and become in several ways a great nuisance. Plaster or wood stopping is not always so efficacious as the use of broken glass in those secret passages which they are prone to frequent. COVERINGS TO GUTTERS, CISTERNS, ETC. The liability of gutters and cisterns to become choked with snow, or filled up with leaves, etc., renders it advisable to protect them with a boarded covering, which may preserve the under-current of water from receiving what may 92 CEDARS. CAV speedily produce a cliokage or overflow. IRON COLUMNS, BEAMS, ETC. On this most important subject the young architect should not move a step without carefully con¬ sulting the experienced knowledge of the engineer. Tredgold’s ‘ Prac¬ tical Essay on the Strength of Cast Iron ’ should be well studied, whenever necessity compels the support of heavy and loaded su¬ perstructures by iron columns and beams. A careful computation of the weight of the mere building, added to that of its possible bur¬ then, with allowance for theoretical fallacy, and a due estimate of the increased strength of the hollow pillar, as compared with a solid one having the same amount of metal, must be made, examined, and re-examined, before the speci¬ fication be issued. Cavcedium, one of the courts of a Roman house, most commonly sur¬ rounded by a covered passage, having the middle area exposed to the air. There are five kinds of cavaedia, which, from their mode of construction, are severally deno¬ minated Tuscan, Corinthian, tetra- style, displuviatum, and testudi- natum. They are termed Tuscan when the beams which are thrown across the court have timbers and gutters extending diagonally from the angles made by the walls of the court to those made by the junction of the beams, and the rafters of the eaves are made to incline every way towards the centre of the compluvium. The timbers and compluvia of Corinthian cavaedia have a disposition, in all respects, similar; but beams are made to project from the walls, and are supported upon columns arranged around the court. Cavazion, in architecture, the hollow trench made for laying the foun¬ dation of a building; according to CED Vitruvius, it ought to he one-sixth part of the height of the whole building. Cavetto, a hollow moulding whose profile is a quadrant of a circle; principally used in cornices. Cavendish (the Hon. Henry), one of the most learned men in chemistry and the arts of his age. Born 10th October 1731; died 24th Febru¬ ary, 1810. An octavo volume, pub¬ lished by the Cavendish Society in 1851, very copiously adduces evidences of Mr. Cavendish’s prior claim to the discovery of the theory of the composition of air and water : the volume contains many valuable papers on the life and experimental labours of Cavendish, and the relative merit of Cavendish; on Watt and Lavoiser and others ; inquiries of the learned men of the latter end of the last, and the be¬ ginning of the present century. CawJc-stone, a mineral, akin to the white milky, mineral juice of lead mines. Caya, a kay or water-lock. Cede, an old English term for a ca¬ nopy. Cedar. Cedar-wood was known an d used in the earliest times, as in the construction of Solomon’s Temple : great varieties are produced in the eastern and western parts of the world: it is used in ship-building, cabinet-work, pencil-making, and for various other purposes. Cedars of Lebanon, of great age and size, constitute a peculiar and very observable feature in the landscape of the suburbs of London, and are unusually numerous on the west and south-west sides as the ad¬ juncts of stately mansions or ele¬ gant villas, along the valley of the Thames. Poplars (Lombardy) are very freely introduced into the scenery around London. Beeches do not appear at home anywhere along the flat grounds near the Thames; but at Burnham, a little below Slough, there are some celebrated ones, 93 CEI CEMENTS. CEM growing on a thin, light, gravelly soil, and Windsor Park contains some superb specimens. Chestnuts (of Spanish) we shall have some prodigious specimens to notice on a property of the Duke of Devonshire, near Chiswick. In Kensington Gardens, Greenwich Park, and other places, there are some very fine ones. It is a first- rate park tree for the low sheltered tract by the sides of the Thames, and is hardly enough esteemed. Ceiling , the upper side of an apart¬ ment, opposite to the floor, gene¬ rally finished with plastered work. Ceilings are set in two different ways: the best is where the setting- coat is composed of plaster and putty, commonly called ‘ gauge.’ Common ceilings have plaster, but no hair: the latter is the same as the finishing coat in walls set for paper. Ceiling , the under covering of a roof, under the surface of the vaulting in vaulted rooms and buildings. Ceil¬ ings in buildings of any dimensions at either story are the upper or overhead surfaces of the rooms respectively. Ceilings. When ceilings are covered, the height of the cove should be regulated by the total height of the room. In proportioning the height of a room to its superficial dimen¬ sions, the best proportion for the cove is one-quarter of the whole height. Celerity is the velocity or swiftness of a body in motion ; or that affec¬ tion of a body in motion by which it can pass over a certain space in a certain time. Cell, an enclosed space within the walls of an ancient temple; a term applied also to monkish sleeping- rooms in religious establishments. Celia, the body or principal part of a temple,—anciently written cela. It is thought to be derived from celandus, —to be concealed or shut out from public view; because in early emple the cella could 94 only be entered by privileged , persons. Cellarino, that part of the capital in i the Roman, Doric, and Tuscan orders which is below' the annulets under the ovolo. Cellular beam. A newly introduced application of wrought-iron to the purposes of girders and beams, in which wrought-iron plates are riveted with angle-irons in the form of a series of longitudinal cells with occasional struts. Cemetery, a place wherein the bodies of the dead are buried; a church¬ yard or burying-ground. Cementation is the process of con¬ verting iron into steel, which is ' done by -stratifying bars of iron in charcoal, igniting it, and letting them continue in a kiln in that state for five or six days : the carbon of the charcoal is thus absorbed by the iron, and the latter converted into steel. Cements, natural. When the propor¬ tion of clay in calcareous minerals exceeds 27 to 30 per cent., it is seldom that they can be converted into lime by calcination; but they then furnish a kind of natural ce¬ ment, which may be employed in !i the same manner as plaster of Paris, ] by pulverizing it, and kneading it i with a certain quantity of water. There are some natural cements | which do not set in water for many . > days, and some which harden in ;| less than a quarter of an hour: i these last are the only ones which : have been made use of at present. Though very useful in circum¬ stances where a quick solidification is indispensable, they are far from affording, in ordinary cases, the advantages of hydraulic mortars or cements of good quality. In fact, they merely adhere to the stone, owing to the roughness of its sur- i face, and the entanglement result- j ingfromit; and,however dexterous or experienced the workman may be who makes use of them,he w'ill be unable to connect the different CEM CEMENTS. parts of his masonry in one conti¬ nuous bond by means of them. This statement must be understood to apply only to cements which harden while in contact with bricks under water, because the adhesion of such as dry in the open air is well known to he much greater than what would be caused merely by asperities of the surface. It is not uncommon to see from twenty to thirty bricks stuck to one an¬ other by Roman cement, and pro¬ jecting at right angles from the side of a wall, as a proof of the excellence of the composition ; and an instance has been mentioned in which thirty-three bricks were suc¬ cessfully supported in this manner. Now, if we assume the weight of a brick and its corresponding joint of cement to be 6 lbs., and their thickness, when the bricks were joined one to another in the man¬ ner above alluded to (in which the longest dimension of the brick was placed vertically), to be 2-§ inches, then the cohesive force necessary to unite the first brick to the wall, with sufficient firmness to bear the strain occasioned by the weight of the remaining thirty-two supported hv it, must have been nearly 9libs, per square inch, or equivalent to a direct load of 3640 tbs. upon its whole surface of about 40 square inches. That which is in England very improperly termed Roman cement is nothing more than a natural ce¬ ment, resulting from a slight calci¬ nation of a calcareous mineral, containing about 31 per cent, of ochreous clay,and a few hundredths of carbonate of magnesia and man¬ ganese. A very great consumption of this cement takes place in Lon¬ don ; but its use will infallibly be¬ come restricted, in proportion as the mortars of eminently hydraulic lime shall become better known, and, in consequence, better appre¬ ciated. Very recently, natural cements CEM have been found in Russia and in France. They may be composed at once by properly calcining mix¬ tures made in the average propor¬ tions of 66 parts of ochreous clay to 100 parts of chalk. It is fair, however, to admit, that no artificial product has yet been proved to equal the English cement in point of hardness. The pure calcareous substances, when imperfectly calcined, become converted into sub-carbonates, pos¬ sessed of certain properties. These properties are to afford a powder, which, when kneaded with water In the same way as plaster of Paris, acquires in it, at first, a consistency more or less firm, but which does not continue its progress at the same rate. The argillaceous limestones, and the artificial mixtures of pure lime and clay in the proportions requi¬ site to constitute hydraulic lime by the ordinary calcination, become natural or artificial cements when they have been subjected merely to a simple incandescence, kept up for some hours, or even for some minutes. This result, which has often occurred in the course of first experiments in burning the artificial hydraulic limestones, has been equally observed in Russia by Colonel Raucourt; and M. Lacor- daire, Engineer of Roads, has not only fully verified it with respect to the different argillaceous lime¬ stones of the neighbourhood of Pouilly, hut has also made a use¬ ful and happy application of it in the works which have been erected at the junction of the Burgundy canal; both in transforming these limestones into natural cements, and in turning to account the large quantity of half-burnt lime which is found in the upper layers of the kilns, when the intensity and du¬ ration of the heat is so regulated as not to exceed the limit proper for the lower strata of the charge. The history of these new cements CEN CENTRE FRAMES. CEN will not be complete until authentic and multiplied experiments shall have established their power to resist the effects of air and frost, and the degree of adhesion with which they unite to the building- stone. Cenotaphium, a cenotaph, an empty or honorary tomb, erected by the Greeks as a memorial of a person whose body was buried elsewhere, or not found for burial. Censitores, surveyors of the Roman aqueducts. Centaur, poetically, and in ancient mythology, a being represented as half man half horse; the Sagitta¬ rius of the Zodiac. Centering, temporary supports, prin- cipally of timber, placed and affixed under vaults and arches to sustain them while they are in course of building. Much ingenuity is dis¬ played in the centering for bridges and tunnels. Centigrade, the division into grades or degrees by hundredth parts; called also centesimal. Central forces, the powers which cause a moving body to tend to¬ wards or recede from the centre of motion. When a body is made to revolve in a circle round some fixed point, it will have a continued tendency to fly off in a straight line at a tangent in the circle, which tendency is called the centrifugal force ; and the opposing power by W'hich the body is retained in the circular path is called the centri¬ petal force. Centre, any timber frame, or set of frames, for supporting the arch¬ stones of a bridge during the con¬ struction of an arch. The qualities of a good centre consist in its being a sufficient sup¬ port for the weight or pressure of the arch-stones, without any sen¬ sible change of form taking place throughout the whole progress of the work, from the springing of the arch to the fixing of the key¬ stone : it should be capable of being easily and safely removed, and de¬ signed so that it may be erected at a comparatively small expense. In navigable rivers, where a cer¬ tain space must be left for the pas¬ sage of vessels, and in deep and rapid rivers, where it is difficult to establish intermediate supports, and where much is to be appre¬ hended from sudden floods, the frames should span the whole width of the archw r ay, or be framed so as to leave a considerable portion of the archway unoccupied. In such cases, a considerable degree of art is required to make the centre an effectual support for the arch¬ stones, particularly when the arch is large. But in narrow rivers, and in those where the above-mentioned inconveniences do not interfere with the work, the framing may be constructed upon horizontal tie- beams, supported in several places by piles, or frames fixed in the bed of the river; and the construction is comparatively easy. In large arches, when the arch¬ stones are laid to a considerable height, they often force the centre out of form, by causing it to rise j at the crown; and it is sometimes ; necessary to load the centre at the i crown to prevent such rising; but this is a very imperfect remedy. ! Notwithstanding the subject has been considered by several very eminent men, their works are not much calculated to instruct the carpenter how to avoid this diffi¬ culty: indeed, their object seems to have been exclusively to calcu¬ late the strength of a centre already j designed, instead of showing the principles on which it ought to be contrived; and even in calcu¬ lating the strength, they are very imperfect guides, because they have not attempted to find what forces would derange a centre, but only the force that might be supported without fracture. Centre, in a general sense, denotes a point equally remote from the ex- 96 CEN tremes of a line, surface, or solid: the word signifies a point. Centre-lit , in joinery, an instrument with a projecting conical point nearly in the middle, called the , centre of the bit: on the narrow I vertical surface, the one most re¬ mote from the centre, is a tooth with a cutting edge. The under edge of the bit on the other side of the centre has a projecting edge inclined forward. The horizontal section of this bit upwards is a , rectangle. The axis of the small I cone in the centre is in the same straight line as that of the stock ; the cutting edge of the tooth is more prominent than the projecting edge on the other side of the cen¬ tre, and the vertex of the conic centre is still more prominent than the cutting edge of the tooth. The use of the centre-bit is to form a cylindric excavation, having the upper point of the axis of the intended hole given on the surface of the wood. The centre of the bit is first fixed in this point; then, by placing the axis of the stock and bit in the axis of the hole intended to be bored, with the head of the stock against the breast, and by turning the stock swiftly round by means of the handle, the hollow cone made by the centre will cause the point of the tooth to move in the circumference of a circle, and cut the cylindric surface progres¬ sively as it is turned round, while the projecting edge upon the other side of the centre will cut out the cone in a spiral-formed shaving. Centre-bits are of various sizes, for bores of different diameters. Centre-chuck , a chuck which can be screwed on the mandril of a lathe, and has a hardened steel cone or centre fixed in it; also a projecting arm or driver. Centre-drill, a small drill used for making a short hole in the ends of a shaft about to be turned, for the entrance of the lathe centres. Centre of attraction of a body is that CEN r point into which, if all its matter were collected, its action upon any remote particle would still be the same as it is while the body retains its own proper form ; or it is that point to which bodies tend by their own gravity, or about which a planet revolves as a centre, being attracted or impelled towards it by the action of gravity. The common centre of attraction of two or more bodies is used to denote that point in which, if a particle of matter j were placed, the action of each body upon it would be equal, and where it will remain in equilibrium, | having no tendency to move one | way rather than another. Centre of a circle, that point in a I circle which is equally distant from j every point of the circumference, | being that from which the circle is described. Centre of a conic section, that point which bisects any diameter, or that ■’ point in which all the diameters intersect each other. This point in an ellipse is within the figure, in the hyperbola without, and in the parabola it is at an infinite distance. Centre of conversion, a mechanical term, the signification of which may be thus conceived : if a stick be laid on stagnant water, and drawn by a thread fastened to it, so that the thread makes always the same angle with it, the stick will be found to turn about a certain point, which point is called the ‘ centre of conversion.’ Centre of a curve of the higher kind, is the point where two diameters concur; and when all the diameters concur in the same point, it is called the general centre. Centre of a dial, that point where the gnomon or style, placed paral¬ lel to the axis of the earth, inter¬ sects the plane of the dial. Centre of an equilibrium is the same with respect to bodies immersqd in a fluid as the centre of gravity is to bodies in free space; or it is a certain point on w'hich, if a body, CENTRE-BIT. CEN CENTRE OF GRAVITY. CEN or system of bodies, be suspended, they will rest in any position. Centre of friction is that point in the base of a body on which it revolves, in which, if the whole surface of the base and the mass of the body were collected and made to revolve about the centre of the base of the given body, the angular velocity destroyed by its friction would be equal to the angular velocity de¬ stroyed in the given body by its friction in the same time. Centre of gravity of any body, or sys¬ tem of bodies, is that point upon which the body or system of bodies acted upon only by the force of gravity will balance itself in all positions; or it is a point on which, when supported, the body or sys¬ tem will be supported, however it may be situated in other respects. Hence it follows, that if a line or plane passing through the centre of gravity be supported, the body or system will also be supported; and conversely, if a body or system balance itself upon a line or plane, in all positions, the centre of gravity is in that line or plane. In a simi¬ lar manner it will appear, that if a body rest in equilibrio when sus¬ pended from any point, the centre of gravity of that body or system is in the perpendicular let fall from the centre of suspension ; and on these principles depends the me¬ chanical method of finding the cen¬ tre of gravity of bodies. Centre of gyration, that point in a body revolving on an axis, into which, if the matter of the whole body were collected, the same an¬ gular velocity would be generated by the same moving force. Centre of motion of a body is a fixed point about which the body is moved ; and the axis of motion is the fixed axis about which it moves. Centre of oscillation, the point in which the whole of the matter must be collected, in order that the time of oscillation may be the same as when it is distributed. Centre of percussion, that point of a revolving body which would strike an obstacle with the same force as if the whole of the matter were collected in it. Centre of position, in mechanics, de¬ notes a point of any body, or system of bodies, so selected that we may properly estimate the situation and motion of the body or system by those points. Centre of pressure, or metacentre of a fluid against a plane, is that point against which a force being applied, equal and contrary to the whole pressure, it will sustain it, so as that the body pressed on will not incline to either side. This is the same as the centre of percussion, supposing the axis of motion to be at the intersection of this plane with the surface of the fluid ; and the centre of pressure upon a plane parallel to the horizon, or upon any plane where the pressure is uni¬ form, is the same as the centre of gravity of that plane v Centre of spontaneous rotation, that point which remains at rest the instant a body is struck, or about which the body begins to revolve. If a body of any size or form, after rotatory or gyratory motions, be left entirely to itself, it will always have three principal axes of rota¬ tion ; that is, all the rotary motions by which it is effected may be con¬ stantly reduced to three, which are performed round three axes per¬ pendicular to each other, passing through the centre of gravity, and always preserving the same position in absolute space, while the centre of gravity is at rest, or moves uni¬ formly forward in a right line. Centre phonic, in acoustics, the place where the speaker stands in mak¬ ing polysyllabical and articulate echoes. Centre phonocamptic, the place or object which returns the voice. Centre-punch , a small piece of steel with a hardened point at one end. Centres, in turnery, are the two cones 98 CEN CHAINS. CHA with their axes horizontally posited for sustaining the body while it is turned. Centre-velic or Velic-point, the centre of gravity of an equivalent sail, or that single sail whose position and magnitude are such as cause it to he acted upon by the wind when the vessel is sailing, so that the motion shall be the same as that which takes place while the sails have their usual positions. Centrifugal force is that force by which a body revolving about a centre, or about another body, has a tendency to recede from it. Centrifugal pump , a machine for raising water by centrifugal force combined with the pressure of the atmosphere. Centripetal force is that force by which a body is perpetually urged onwards to a centre, and thereby made to revolve in a curve instead of a right line. Ceramics, a term for all the varieties of baked or burnt clay. \ Cerium, a metal discovered in 1803 by Berzelius, and named after the planet Ceres. It is brittle, white, and volatile in a very intense heat: it is not acted upon by nitric acid, but is dissolved in aqua regia, nitro- hydrochloric acid. \ Cesspool, a receptacle, sunk below the level of a drain from a privy or water-closet, for the sediment which would otherwise choke the drain. Cerceau (A. du), architect: practised in France in 1575, and built se¬ veral magnificent palaces and mansions for Royalty and for the nobility. Cerceau (J. A. du), architect: born in 1516, at Orleans ; died in 1592. He published valuable books on the architecture of the period. i Chafery, a forge in an iron mill, wherein the iron is wrought into bars. lhain, in surveying, is a lineal mea¬ sure, consisting of a certain number of iron links, usually 100, serving to take the dimensions of fields, etc.: at every tenth link is usually fastened a small brass plate, w'itli a figure engraved upon it, or else cut into ditferent shapes, to show how many links it is from one end of the chain. Chains, strong links or plates of iron, the lower ends of which are bolted through a ship’s side to the tim¬ bers. Chain-plates, plates of iron bolted to the side of a ship, to which the chains and dead-eyes of the lower rigging are connected. Chain-pump, an hydraulic machine for raising water. It is made of different lengths, and consists of two collateral square barrels and an endless chain of pistons of the same form, fixed at proper distances. Chain-timber, in brick-building, a timber of large dimensions placed in the middle of the height of a story, for imparting strength. Chairs. Anciently, in most apart¬ ments we find “ two great chayers these were arm-chairs, with stuffed backs and sides, entirely covered, and similar to the lounging-cliairs of the present day. Others are described as ‘ Flemish chairs,’ ‘ scrolled chairs,’ and ‘ turned chairs,’ wrought in ebony, W'alnut, cherry-tree, etc., with high backs, either stuffed in one long upright panel, or filled with wicker-work,etc. Chalcedony, a precious stone, in co¬ lour like a carbuncle; by some trans¬ lated from the Scriptures as ‘ eme¬ rald.’ Chalcidicum, among the Romans, a large, low, and deep porch, covered with its own roof, supported on pilasters, and appended to the en¬ trance-front of a building, where it protected the principal doorway, and formed a grand entrance to the whole edifice. Chalcidria, chambers attached to a basilica ; they were built at one end when the situation would allow. I Chalcographer, an engraver in copper. CHANTING. CHA CHA Chalice, the cup used for the wine at the celebration of the Eucharist. Chalinque, a boat which is almost of a square building, used in Italy. Chalk, in geology, forms the higher part of the series or group termed cretaceous : it is composed of nearly 44 parts of carbonic acid and 56 parts of lime. Chamber of a mine, the place where the powder is fixed. Chambers (Sir William), born in Stockholm in 1725, was an emi¬ nent architect of the reign of George III. In the year 1768 was instituted the Royal Academy, to the establishment of which Cham¬ bers was principally instrumental. In 1775 he was appointed by the Government to construct the mag¬ nificent edifice of Somerset House, which was commenced in the fol¬ lowing year. Sir William Cham¬ bers had social intimacy with Drs. Johnson, Goldsmith, Burney, and Garrick, and other literary men of his day ; he published several ar¬ chitectural works, among them the celebrated work on the decorative part of civil architecture, which Mr. Joseph Gwilt has re-edited and improved. Died in London 1796. Chambers, according to Palladio, are made either arched or with a flat ceiling: if in the last way, the height from the floor to the joist above ought to be equal to their breadth ; and the chambers of the second story must be a sixth part less than them in height. Cliambranle, an ornament in masonry and joiners’ work which borders the sides of doors, windows, and chimneys. Chandry, an apartment in a prince’s house, where the candles and other lights are kept. Chamfer. An edge or arris, taken off equally on the two sides which form it, leaves what is called a chamfer, or a chamfered edge. If the arris be taken off more on one side than the other, it is said to be splayed or bevelled. Chamfering, the process of cutting the edge or the end of anything bevel or aslope. Champ, the flat surface of a wall. Champe, the field or ground on which carving is raised. Champ de Mars : in French history, the public assemblies of the Franks are said to have been held in an open field, and in the month of March; whence the name. Chancel, the choir or eastern part of a church appropriated to the use of those who officiate in the perform¬ ance of the services, and separated from the nave and other portions in which the congregation assemble, sometimes by a screen. Channel, in hydrography, the deepest part of a river, harbour, or strait, which is most convenient for the track of shipping; also an arm of the sea running between an island and the main, or continent, as the British Channel, etc. Channelling, in architecture, perpen¬ dicular channels, or cavities, cut along the shaft of a column or pilaster. Channels, broad pieces of plank bolted edgewise to the outside of a vessel, used for spreading the lower rig- ging. Chant, Chanting. The word ‘ chant ’ is derived from the Latin Cantus, which signifies singing ; a song, a tune, or melody,—the sound of a trumpet, crowing of a cock (whence this bird is called ‘ chanticleer ’): it also signifies the frequent repe¬ tition of the same thing. The word chant is not confined to merely a melody consisting of several notes ; it may consist of one only : in this case it is called, in church music, ‘intonation,’ although in Gregorian music the word intonation has a somewhat different signification. (See Gregorian Chant.) Hence chanting is reciting in a musical tone, and is peculiarly adapted to a dignified utterance of the sublime language of the Liturgy. Chant¬ ing or intoning on a monotone, or CHAPEL. CHA single sound, is the simplest and easiest method of reading and re¬ sponding the various prayers, ex¬ hortations, litanies, suffrages, Kvrie eleisons, Allelujahs, Gloria Patri, and the Amens, and is eminently more dignified and solemn than when there is neither elevation nor depression of the voice at any one termination. In chanting the greater and lesser Canticles,—the Te Deum, Jubilate, Benedicite, Benedictus, Athanasian Creed, Ve- nite exultemus, Magnificat, Can- tate Domino, Nunc dimittis, Deus misereatur, as also the prose Psalms,—the chant may consist of more than one tone, although it is preferable to use a small number. The method of chanting the Psalter in the English church is different from that adopted on the Conti¬ nent, where it appears to be go¬ verned by no rule; whereas the Gregorian chant is governed en¬ tirely by rule. Chantlate, in building, a piece of wood fastened near the ends of the rafters, and projecting beyond the wall, to support two or three rows of tiles, so placed to hinder the rain-water from trickling down the sides of the walls. Chantry , an ecclesiastical benefice or endowment to provide for the chanting of masses. Chapel, a small building attached anciently to various parts of large churches or cathedrals, and sepa¬ rately dedicated ; also a detached building for divine service : in Eng¬ land chapels are sometimes called chapels of ease, built for the ac¬ commodation of an increasing po¬ pulation. Chapelling, wearing a ship round, when taken aback, without bracing the head-yards. Chapiter, the capital of a column. Chaplet , in architecture, a small orna¬ ment carved into round beads, etc. 1 Chapman (Admiral), born in the last century, in Sweden, of English descent. His naval architectural CHE works on men-of-war and mer¬ chant-vessels are, as examples of principles, to practice the most eminent. The plates are drawn to a large scale, both in English and Swedish measurements. Chaps, the two planes or flat parts of a vice or pair of tongs or pliers, for holding anything fast, and which are generally roughed with teeth. Chapter-house, an establishment for Deans and Prebendaries of cathe¬ drals and collegiate churches; the apartment or hall in which the monks and canons of a monastic establishment conduct their affairs connected with ecclesiastical regu¬ lations. Char or Chare, to hew, to work charred stone; hewn stone. Character, in a picture, is giving to the different objects their appro¬ priate and distinguishing appear¬ ance. Charcoal consists mainly of carbon procured from the decomposition of wood by burning. This ope¬ ration is generally conducted in pits made in the ground, and in iron cylinders. Wood is essentially composed of carbon, oxygen, and hydrogen. Charcoal has the same properties : it is black, lighter than water, and full of pores, occasioned by the expulsion of the bodies vo¬ latilized. Charge, in electricity, is the accumu¬ lation of the electric matter on one surface of an electric, as a pane of glass, Leyden phial, etc., whilst an equal quantity passes off from the opposite surface. Charge, in mining: any quantity of ore put at one time into a furnace to fuse is called a 1 chargeletting it out is called ‘ tapping.’ Chargers, large dishes, sometimes de¬ scribed as ‘ flat pieces.’ Chatelet, the common gaol and ses¬ sion-house in the city of Paris. Cheeks, the shears or bed of the lathe as made with two pieces for con¬ ducting the puppets. Checks, the projection on each side 101 CHEMISTRY. CHE of a mast, upon which the trestle- trees rest; the sides of the sheet of a block. Cheeks. Two upright, equal and si¬ milar parts of any piece of timber work, as the sides of a dormer- window. Cheeks (of a mortise) are the two solid parts upon the sides of the mortise. The thickness of each cheek should not be less than the thickness of the mortise, except mouldings on the stiles require it to be otherwise. Cheerly, quickly ; with a will. Chemistry. The science of chemistry has for its object the study of the nature and properties of the dif¬ ferent substances of which the earth, the waters, the air, and their inhabitants (namely, plants and animals), are composed. In a word, it embraces the study of everything under heaven accessible to man. In its highest branches it aims at discovering the laws or rules which regulate the formation of chemical compounds generally ; and in its useful applications it has been already exceedingly service¬ able in directing and improving the various arts of common life, as agriculture, the working of metals, dyeing, and many other pursuits. It serves also to guide the medical man in the preparation of his re¬ medies, and also occasionally in distinguishing between diseases which are in other respects much alike. There is, indeed, scarcely a situation in life in which a know¬ ledge of chemistry may not prove directly useful. It is a science the study of which, from its simplest beginnings to its highest attempts, is rendered delightful by the con¬ stant succession of new and inter¬ esting things brought before the eye and the mind. Cherry-tree, a hard, close-grained wood, of a pale red-brown colour : when stained with lime, and oiled and varnished, it resembles maho¬ gany, and is used for furniture, etc. CHE Chess-trees, nieces of oak fitted to the sides of a vessel, abaft the fore¬ chains, with a sheave in them, to board the main-tack to ; not much used. Chest, a piece of furniture for the re¬ ception of all kinds of goods, par¬ ticularly household conveniences, deposited therein for security, and for plate ; placed also in churches, for the keeping of the holy ves- 1 sels, vestments, etc. : the seaman’s chest contains all the personalities of a sailor. Coffers and chests were the general repositories for articles of every kind : writings, apparel, food, and even fuel, were kept within them. Many of these chests which were raised on feet to protect them from damp and vermin, were beau¬ tifully ornamented with carving and other sumptuous enrichments. Large trunks, in which clothes, hangings, etc., were packed for removal, were called ‘ Trussing Cheststhey were substantially made, and bound in every direction with iron straps, wrought into fan¬ ciful forms, and secured by locks of artful and curious contrivance. Two “ standard chests ” were de¬ livered to the laundress of King Henry VIII.; “ the one to keep the cleane stuff, and the other to keep the stuff that had been occupied.” “ In ivory coffers,” says Grameo, “ I have stuffed my crowns ; in cypress chests, my arras, counter¬ points, etc.” Cypress-wood was selected for its rare properties of neither rottingnor becomingworm- eaten. Chestnut wood is very durable, and was formerly much used in house carpentry and furniture. Cheval de frise, a square or octagonal beam of wood, from 6 to 9 feet in length, and pierced by iron rods or wooden pickets 6 feet long, which j are pointed at each end, and shod with iron : the pickets are placed 6 inches asunder, and pass through two opposite faces of the beam, in 102 CHE CHIMNEY-PIECES. CHI directions alternately at right an¬ gles to each other, the cheval resting on the ground at the lower extremity of the pickets. Chevet, the termination of a church behind the high altar, when of a semicircular or polygonal form. Chevron, a moulding of a zig-zag cha¬ racter, of the Norman style parti¬ cularly, but sometimes to be found with the pointed arch. Chiaro-oscuro, a drawing made in two colours, black and white; also the art of advantageously distributing the lights and shadows which ought to appear in a picture, as well for the. repose and satisfaction of the eye as for the effect of the whole together. Chief point (in do.) is the uppermost part of an escutcheon. Chiliad, an assemblage of several things ranged by thousands; ap¬ plied also to tables of logarithms, which were at first divided into thousands. Chiliaedron, a solid figure of a thou¬ sand faces. Chiliagon, in geometry, a regular plane figure of a thousand sides and angles. Chimes, a set of bells tuned to the modern musical scale, and struck by hammers acted on by a pinned cylinder, or barrel, which revolves by means of clock-work : also ap¬ plied to the music or tune pro¬ duced by mechanical means from the bells in a steeple, tower, or common clock. Chimney, in locomotive engines. The chimney is regulated in size for each engine so as to act in union with the blast-pipe, to produce a proper blast on the fire. This is done by each exhaust of steam from the cylinders creating a partial vacuum in the chimney : hence a rush of air takes place through the fire and tubes to fill this vacuum ; nd these successive rushes of air blow the fire.’ This vacuum ranges from 2 to 8 inches of a water-gauge. The mild blast produces the least vacuum and the least consumption of fuel. Chimney-pieces. The Egyptians, the Greeks, and the Romans, to whom architecture is so much indebted in other respects, living in warm climates, where fires in the apart¬ ments were seldom necessary, have thrown but little light on this branch of the science. Palladio only mentions two, which stood in the middle of the rooms, and con¬ sisted of columns, supporting archi¬ traves, whereon were placed the pyramids or funnels through which the smoke was conveyed. Scamozzi mentions only three in his time, placed similarly. In England, Inigo Jones designed some very elaborate chimney-pieces. The size of the chimney must depend upon the dimensions of the room wherein it is placed: the chimney should always be situated so as to be im¬ mediately seen by those who enter: the middle of the side partition wall is the best place in halls, sa¬ loons, and other rooms of passage, to which the principal entrances are commonly in the middle of the front or of the back wall; but in drawing-rooms, dressing-rooms, etc., the middle of the back wall is the best situation ; the chimney being then farthest removed from the doors of communication. Chinese architecture, a style peculiar to China, where the material em¬ ployed is principally wood. It is a style not congenial to English taste or climate: its monstrosity may be seen at Brighton. Chinese Yellow (colour), a very bright sulphuret of arsenic, brought from China. Chinse, to thrust oakum into seams with a small iron. Chisel, a tool with the lower part in the form of a wedge, for cutting iron plate or bar, and with the upper part flat, to receive the blows of a hammer, in order to force the cutting edge through the substance of the iron. 103 CHI CHISELS. CHI Chisel, an instrument used by car¬ penters. The large chisels used by millwrights for heavy work are generally composed of iron and steel welded together. Chisels are also employed in turning, and they are driven more or less by blows : those used by the joiners are similar; but those used by cabinet-makers are straight across the end. Chisels in general. A chisel is an edge tool for cutting wood, either by leaning on it or by striking it with a mallet. The lower part of the chisel is the frustrum of a cuneus or wedge ; the cutting edge is al¬ ways on and generally at right angles to the side. The basil is ground entirely from one side. The two sides taper in a small de¬ gree upwards, but the two narrow' surfaces taper downwards in a greater degree. The upper part of the iron has a shoulder, which is a plane surface at right angles to the middle line of the chisel. From this plane surface rises a prong in the form of a square pyramid, the middle line of which is the same as the middle line of the cuneus or wedge : the prong is inserted and fixed in a socket of a piece of wood of the same form : this piece of wood is called the handle, and is generally the frustrum of an octa¬ gonal pyramid, the middle line of which is the same as that of the chisel: the tapering sides of the handle diminish downwards, and terminate upwards in an octagonal dome. The use of the shoulder is for preventing the prong from split¬ ting the handle while being struck with the mallet. The chisel is made stronger from the cutting edge to the shoulder, as it is some¬ times used as a lever, the prop being at or very near the middle, the pow'er at the handle, and the resistance at the cutting-edge. Some chisels are made with iron on one side and steel on the other, and others consist entirely of steel. There are several kinds of chisels, as the mortise-chisel, the ripping- chisel, and the socket-chisel. Chisel, the firmer, is formed in the lower part similar to the socket- chisel ; but each of the edges above the prismoidal part falls into an equal concavity, and diminishes upwards until the substance of the metal between the concave narrow surfaces becomes equal in thickness to the substance of that between the other two sides, produced in a straight line, and meeting a protu¬ berance projecting equally on each side. The firmer chisel is used by carpenters and joiners in cutting away the superfluous wood by thin chips: the best are made of cast steel. When there is a great deal of superfluous wood to be cut away, sometimes a stronger chisel, con¬ sisting of an iron back and steel face, is first used, by driving it into the wood with a mallet; and then a slighter one, consisting entirely of steel sharpened to a very fine edge, is used in the finish. The first used is called a firmer, and the last a paring chisel, in the application of which only the shoulder or hand is employed in forcing it into the wood. Chisel, the mortise, is made exceed¬ ingly strong, for cutting out a rectangular prismatic cavity across the fibres, quite through or very deep in a piece of wood, for the purpose of inserting a rectangular pin of the same form on the end of another piece, and thereby uniting the two. The cavity is called a mortise, and the pin inserted a tenon ; and the chisel used for cut¬ ting out the cavity is, therefore, called a mortise-chisel. As the thickness of this chisel from the face to the back is great, in order to withstand the percussive force of the mallet, and as the angle which the basil makes with the face is about 25°, the slant dimen¬ sion of the basil is very great. This chisel is only used by percussive force given by the mallet. Chisel, the ripping, is only an old 104 I CHI CHORAGIC MONUMENTS. CHR socket-chisel used in cutting holes in walls for inserting plugs, and for separating wood that has been j nailed together, etc. Chisel, the socket, is used for cutting excavations: the lower part is a prismoid, the sides of which taper in a small degree upwards, and the edges considerably downwards: one side consists of steel, and the other of iron. The under end is ground into the form of a wedge, forming the basil on the iron side, and the cutting edge on the lower end of the steel face. From the upper end of the prismoidal part rises the frustrum of a hollow cone, in¬ creasing in diameter upwards : the cavity or socket contains a handle of wood of the same conic form : the axis of the handle, the hollow cone, and the middle line of the frustrum,are all in the same straight line. The socket-chisel, which is commonly about or inch broad, is chietly used in cutting mortises, and may be said to be the same as the mortise-chisel em¬ ployed in joinery. Chisel, in turnery, a flat tool, skewed in a small degree at the end, and bevelled from each side, so as to make the cutting edge in the middle of its thickness. Chock, in navigation, a wedge used to secure anything with, or for any¬ thing to rest upon. The long-boat rests upon two large chocks when it is stowed. 1 Chocolate lead, a pigment prepared by calcinating oxide of lead with about a third of that of copper, and reducing the compound to a uniform tint by levigation. Choke. An adit is said to be choked when any earth or stone falls in and prevents the current of water through it: the place or part so filled is called ‘ the choke.’ Chopping-hlock, a block of wood used for reducing bricks to their intended form by axing them : it is made of any chance piece that can be ob¬ tained, and commonly from 6 to 8 inches square, supported generally upon two 14-inch brick piers, if two men are to work at it; but if four men, the chopping-block must be lengthened and supported by three piers, and so on, according to the number: it is about 2 feet 3 inches in height. Choragic monuments, in Grecian story, monuments in honour of those who had gained a prize as choragus, or leader of the play and choruses. Choragic monument of Lysierates, known as the Lantern of De¬ mosthenes, was built in the 111th Olympiad, and is still entire : it is considered the most exquisite and perfect specimen of the orders. Choragic monument of Thrasycles, etc., now the church of our Lady of the Grotto. It is built against the rock of the Acropolis : above it standtwo columns, onwhich tripods have been placed, and on each side of it the rock has been chiseled away in such form as evidently shows that similar buildings had been erected contiguous to it. Chord, in geometry, is the right line joining the extremities of any arc of a circle. Chorohates (Greek), an instrument for determining the slope of an aqueduct, and the levels of the country through which it was to pass. It differed but slightly from a common carpenter’s level, which consists of a straight rule support¬ ing a perpendicular piece, against which hangs a plumb-line. Chorography, the art of making a map of a particular country or province, or of teaching geography. Chromatics, a division of the science of optics, by which the properties of the colours-of light and of natural bodies are illustrated. Chromaseope, or optical chromatics : there are three species of optical effects of colours,—-that of refrac¬ tion of prisms and lenses, that of the transmission of light through transparent media, and that of the reflection of specula, etc. 3 105 CHRONOMETRICAL GOVERNOR. CHR Chromate of mercury is improperly classed as a red with Vermillion ; for though it is of a bright ochreous red colour in powder, it is, when ground, of a bright orange ochre hue, and affords, with white, very pure orange-coloured tints. Chromatics, the science of the rela¬ tions of light, shade, and colours. Chrome greens are compound pig¬ ments of which chrome yellow is the principal colouring substance. Chrome orange is a beautiful orange pigment,and one of the most durable and least exceptionable chromates of lead, hut not of iron. Chrome yellow is a pigment of modern introduction into general use, and of which there are many varieties, mostly chromates of lead, in which the latter metal more or less abounds. They are distinguished by the pureness, beauty, and brilliancy of their colours, which qualities are great temptations to their use in the hands of the painter; they are, however, far from unexception¬ able pigments. Chromium, a very rare metal, found either in the form of chromate of lead or chromate of iron. Chronometer, a time-keeper, used for determining the longitude at sea, and for other purposes where great accuracy is required. Chronometricalgovernor, an improved regulator for rendering the mean velocity of an engine uniform. The mechanism is as follows : a spindle placed vertically has a pulley fixed upon the top,to receive motionfrom the crank-shaft; below the pulley two bevel-wheels of equal diameters are placed face to face ; the upper wheel is fixed to the spindle, and the lower one is free to turn upon it, and has an arm or crank attached to its under side, to act as a driver for the pendidous hall: between the two wheels, and communicating with them, is a third wheel, fixed upon a spindle placed horizontally, and connected at one end with the vertical spindle, so as to turn round CHU it; the other end is supported by a carriage resting upon a plate, and is connected with a spring or coun¬ ter weight on one side, and on the other side with the throttle-valve; the ball being suspended from a sperical bearing near the top of the rod. The spring is adjusted so that when the velocity of the engine is as required, the upper and lower wheels revolve at the same speed : when the velocity increases, the centrifugal force causes the ball to rise, and retards the motion of the lower wheel; then the inter¬ mediate wheel distends the spring, and moves forward upon the lower wheel as a rack, and closes the throttle-valve: when the velocity diminishes, the ball falls, and the lower wheel requires less power, so that the spring pulls back the inter¬ mediate wheel and opens the valve. The above is a modification of Mr. James Wood’s governor, and is patented by Mr. C. W. Siemans. Chrysolite, a precious stone, probably the tenth on the high-priest’s pec¬ toral, bearing the name of Zebulon : it is transparent, the colour of gold, with a mixture of green, which dis¬ plays a fine lustre. Chuck, a piece of wood or metal fixed on the end of the mandril for keep¬ ing fast the body to be turned. Church Music. By this term is com¬ monly understood all music set to words of a sacred character: hence we have not only the language of Scripture set to music in the shape of anthems, etc., but also metrical versions and paraphrases thereof, used and considered by many as church music. Indeed it too often happens that these are adapted to secular melodies—melodies not ori¬ ginally intended to be applied to words of a sacred character, and yet the music is then termed sacred, probably from an idea that there is no such thing as sacred and profane music. But this is a great error, and arises solely from ignorance of the existence of sacred music,—we 3.06 CHU CHURCH MUSIC. CHU mean especially church music. Ex¬ amine any of the ancient authorized liturgical books, and there will be found an order of music that can¬ not be mistaken for profane, which is not only sacred in its character, but eminently grand, dignified, noble, and sublime; in short, it is for church purposes so superior to all other music, that it alone can properly be called church music. Church music is the music of the holy offices,—is that music in which thewholechurch ,priests and people, can participate. It is easy to exe¬ cute, being simple and. plain (plain chant). It can be sung by every one, and is always most majestic when sung by all; hence it is also called the full chant (cantus ple- nus). For a long period, and until very lately, scarcely a remnant of church music was to be found, even in those places where we had a right to expect to find it: the plain chant was banished entirely in some places, and mutilated in others, so that it could scarcely be discerned; but it is now being restored, and we hear the priest intoning his part in the offices of morning and evening prayer, and the people singing, in response, the ancient authorized melodies of the church ;—we hear the Psalter chanted to fine old (so called) Gregorian tones we hear the Litany chanted to its own proper music, that of the church: we also hear the soul-stirring music in the Communion office, the Gloria in ex- celsis, the Credo, and Sanctus; the latter moreover in its proper place. We can have also, if so disposed, the church music for the matri¬ monial,baptismal, and burial offices, as well as an immense variety of tunes for the metrical psalms, of a true church character, unlike any other kind of music, and which is truly church music, inasmuch as it is the church’s peculiar property, and would be totally misused in any other place. Our definition of church music is, music which is adapted for the services and pur¬ poses of the church, and unfit for any other place or purpose. Church music, such as is here shortly defined, is unisonous; and harmonized music is not fit for congregational purposes ; it is pro¬ per only in those parts of divine worship which may be called extra- liturgical, such as the anthem. Singing harmonized chants, canti¬ cles, Te Deum, etc., is thrusting out the congregation, that is, the chief part of the church present. The harmonies should be left entirely to the discretion of an intelligent organist, to be executed on the organ alone. Harmonized music requires accomplished and well- informed musicians for its perform¬ ance, and can be sung only by the few. The anthem, in cathedral worship, is edifying only when it is performed by the choir-men in a masterly manner, not only with correct musical execution, but with care and attention, to develop all the piety, sublimity, grandeur, dig¬ nity, and whatever else the music is capable of. Before the latter half of the 15th century, the liturgy was chanted in unison ; and it is from this period we can trace the gradual departure from the rigid church style of mu¬ sic, in the compositions of Josquin de Pres especially. In the early part of the 16th century, we find that Adrian Willaert, who was made singing-master at St. Mark’s, Venice, was the first who harmo¬ nized the psalm melodies for two or more choirs ; then followed the mo¬ tet, or harmonized antiphon, which before had been chanted in unison, as it is done at this day in the Ro¬ man Catholic chapels in England, where there are not accomplished singing men to perform the motet. During this century, the use of harmony had not only driven the people away from their part in the performance of the service, but also corrupted the music itself so 107 CHU CINQUE-CENTO. CIR much, that it was only saved from being wholly forbidden by the grave and devotional motets and other compositions of the renown- ed Palestrina, whose works were imitated with great success by the disciples of his school, and this in a very eminent degree by the Eng- glish church musicians. The har¬ monies used by Tallis, Morley, Gibbons, and the rest of the mas¬ ters of church music of this age, are truly sublime. Church ornament consists principally of the painted and stained glass windows of the emblem of the Trinitjq of the passion of our Lord, of the evangelists, sacred mono¬ grams, statues of the holy apostles, of the holy evangelists, and of the saints commemorated by the church. Church in rotundo, that whose plan is a perfect circle, in imitation of the Pantheon. Chymol, a hinge, anciently called a grimmer. Ciborium, an arch supported by four pillars placed over the high altar. Cilery, in architecture, the drapery or leavage that is wrought upon the head of pillars. Cill, the timber or stone at the foot. Ground-cills are the timbers on the ground which support the posts and superstructure. Chnellare , the vestry or room where ' plate, vestments, and other rich ! things belonging to the church are kept. Cincture, a ring, list, or fillet at the top and bottom of a column, serv¬ ing to divide the shaft from the capital and its base. Cinder-frame, in locomotive engines, a wire-work frame placed in front of the tubes, to arrest the ascent of large pieces of ignited coke. Cinque-cento, a term generally archi¬ tecturally applied to the Revival of art, co-eval with the early Tudor style in England and the Renais¬ sance style in France.—In 1506 the church of St. Peter’s at Rome was commenced by Bramante, the greatest monument of the revived classical or Cinque-cento style of architecture, and on the death of Bramante, in 1514, the great Raf- faello continued the building. The Loggia Vaticano is a monument of his fame for its design and orna¬ mentation. Cinque-cento, literally five hundred, or the fifth Century, generally ap¬ plied to the period of the Revival of the arts in Italy and even sub¬ sequently.—The ornament was of an enriched kind, much applied by the Italians, andsince by the French. Cinque-foil, an ornamental foliation or feathering, used in the arches of the lights and tracery of wind- dows, panellings, etc. Cinque Ports, the sea-port towns of Dover, Sandwich, Hastings, Hythe, and Romney, to which three others were afterwards added, viz. Win- chelsea, Rye, and Seaford. These towns possess peculiar privileges, and are under the government of a Lord Warden. Cipher, a secret mode of writing. Cipollino, is a name given by the Ita¬ lians to an impure marble, which containing veins of schistose, de¬ composes and falls off in flakes like the coats of an onion. Cippus (Latin), a low column, some¬ times round, but more frequently rectangular, used as a sepulchral monument. Circmus, a pair of compasses. Those used by statuaries, architects, ma¬ sons, carpenters, etc., were often represented on their tombs. Circinus, according to Vitruvius, a pair of compasses employed by architects, carpenters, etc., for de¬ scribing circles, measuring dis¬ tances, and taking the thickness of solids. Circle, a plain figure contained by one line, which is called the cir¬ cumference, and is such that all straight lines drawn from a certain point within the figure to the cir¬ cumference are equal to one an- 108 CIRCULAR. CIR other, and this point is called the ] centre of the circle. The circumference of a circle is known to be about 3'14159 times its diameter, or, in other words, the ratio of the circumference to the diameter is represented by 3‘14159 : for this number writers generally put the Greek letter it. \ Circular sailing, is that which is performed in the arch of a great circle. Circular saw. Circular saws, revolv¬ ing upon an axis, have the advan¬ tage that they act continually in the same direction, and no force is lost by a backward stroke : they are also susceptible of much greater velocity than the reciprocating saws, an advantage which enables them to cut more smoothly : used principally for cutting mahogany for veneering, and for other woods cut into thin layers. Circus, an area used by the Romans for chariot-races and horse-races, and for other public sports. Cissoid of Diodes, in the higher geo¬ metry, a curve line of the second order. Cistern. There were cisterns through¬ out Palestine, in cities and in pri¬ vate houses. As the cities were mostly built on mountains, and the rains fall in Judea at two seasons only (spring and autumn), people were obliged to keep water in ves¬ sels. There are cisterns of very large dimensions at this day in Pa¬ lestine. Near Bethlehem are the cisterns or pools of Solomon : they are three in number, situated in the sloping hollow of a mountain, one above another, so that the waters of the uppermost descend into the second, and those of the second descend into the third. The breadth is nearly the same in all, between 80 and 90 paces, but the length varies: the first is about 160 paces long; the second, 200 ; the third, 220. These pools for¬ merly supplied the town of Beth¬ lehem and the city of Jerusalem CLA with w'ater. Wells and cisterns, fountains and springs, are seldom correctly described in Scripture. Cistern, in the steam-engine, the vessel which surrounds the con¬ denser, and contains the injection water. Cisterna, an artificial tank or reser¬ voir, sunk in the ground and co¬ vered in with a roof, for the pur¬ pose of collecting and preserving good water for the use of a house¬ hold. Near the baths of Titus are nine subterraneous cisterns, 17J feet wide, 12 feet high, and above 137 feet long. Citrine, or the colour of the citron, is the first of the tertiary class of colours, or ultimate compounds of the primary triad, yellow', red, and blue, in which yellow is the archeus or predominating colour, and blue the extreme subordinate ; for ci¬ trine being an immediate compound of the secondaries, orange and green, of both which yellow is a constituent, the latter colour is of double occurrence therein, while the other two primaries enter singly into the composition of citrine ; its mean or middle hue compre¬ hending eight blue, five red, and six yellow, of equal intensities. Citrine lake is a durable and better drying species of brown pink, pre¬ pared from the quercitron bark. City, a town, an incorporated town, a town having had a bishop’s see. Clack, the valve of a pump piston; the can-lead, in Derbyshire. Clacks, in locomotive engines, the complete valves of the pumps where the ball-valve is enclosed in a frame or cage, to limit its rise, and guide its fall into the steam-tight seat of the orifice of the pipe. Clack-box, in locomotive engines, the box fitted on to the boiler where a ball-clack is placed, to close the orifice of the feed-pipe, and pre¬ vent steam or hot water reaching the pumps. The ball of the clack is raised from its seat by the stroke of the pump-plunger forcing the 109 CLASSIC ORDERS. CLA CLI water against it, which water then passes into the boiler, while the instant fall of the ball prevents egress from the boiler. Clack-door, a square iron-plate screw¬ ed on to the side of a bottom-pump, or small bore for convenience of changing the clack or valve. Clack-seats, in locomotive engines, two recesses in each pump, for the clacks to fit into. Clack-valve, in the steam-engine, a flat valve in the cold-water pump, with a hinge joint. Clamp, a kiln built above the ground, for the purpose of burning bricks in. Clamp, a piece of wood fixed to the end of a board by mortise and tenon, or by groove and tongue, so that the fibres of the one piece, thus fixed, traverse those of the board, and by this means prevent it from casting: the piece at the end is called a clamp, and the board is said to be clamped. Clamps, in naval architecture, thick planks in a ship’s side, which sup¬ port the ends of the beams. Clamping, in joinery: when a piece of board is fitted with the grain to the end of another piece of board across the grain, the first board is said to be clamped. Clamp-nails, used to fasten on clamps in the building of ships. Clasp-nails, are such with heads, brought into a little compass, so that they will sink into the wood. Classic Orders, in architecture : of these there are but three, —the Doric, Ionic, and Corinthian : two others, the Tuscan and Composite, are often improperly classed with them, and the whole denominated ‘ the five orders of architecture.’ Claude Roman, architect of Paris; he designed and executed the grand altar, and, in consideration of the merit of that work, was permitted to be buried before the image of the Virgin, which he had chosen for the place of his interment; he died in 1675, aged 65. ___ Claustura, brushwood for fences and hedges. Cleading, in locomotive engines, is usually made of narrow strips of timber, neatly fitted round the boiler and fire-box, to prevent the radiation of the heat. Externally, this is sometimes covered with zinc, and a coating of dry hair felt is commonly placed between the boiler and the timber, for the same purpose. Clear, in architecture, inside work. Clearing the deads, a term for clearing a shaft or drift, etc. Cleat, a piece of wood used in different parts of a vessel to belay ropes to. Cleavage, in geology, is an indicator of peculiar fossility in certain rocks, which is independent of, and meets at a considerable angle, the surfaces of lamination or de¬ position. Clay slate furnishes the best examples of this phenomenon. Cleithral, a covered Greek temple. Cleithros, an enclosed place; a temple whose roof covers or encloses it. Clench-bolts, in a ship, clenched at the ends where they come through. Clench-nails, are such as will drive without splitting the board, and draw without breaking. Clepsydra, an instrument anciently used by the Egyptians to measure time by the running of water out of one vessel into another; which we call an hour-glass. Clerestory, an upper story or row of windows in a Gothic church, rising clear above the adjoining parts of the building. Clew, the lower corner of square- sails, and the after corner of a fore- and-aft sail. Clew-garnet, a rope for hauling up the clew of a fore-sail or main¬ sail in a square-rigged vessel. Clew-line, a rope for hauling up the clew of a square-sail : the clew- garnite is the clew-line of a course. Clicket, a latch-key; the latch of a door. Clinch, in navigation, the great ring connected with the mooring-chains. 110 COAL. CLI Clinch, a half-hitch stopped to its own part. Clinker-bar, in steam-engines, the bar fixed across the top of the ash-pit for supporting the rods used for clearing the fire-bars. Clinkers, bricks which, by the vio¬ lence of the fire, are run together and glazed over; hard bricks im¬ ported from Holland, so called. Cloaca, a common sewer. _The term cloaca is generally used in reference to those spacious subterraneous vaults, either of stone or brick, through which the foul waters of the city, as well as all the streams brought to Rome by the aque¬ ducts, finally discharged themselves into the Tiber; according to Livy, a large subterranean canal, con¬ structed of masonry or brick-work, for the purpose of carrying off the rain-water from the streets of a town, and the impurities from private houses, which were thus discharged into some neighbouring river. Cloacarium, the sewers-rate ; a tax which was levied in Rome for the expenses of cleansing and repair¬ ing the sewers. Cloister, a covered ambulatory, form¬ ing part of a monastic or collegiate establishment. Cloisters are always attached to a college cathedral, and arranged round three or four sides of a quadrangular area, with large windows, not often glazed, looking into the quadrangle. Close-hauled, a term applied to a ves¬ sel sailing with her yards braced up so as to get as much as possible to windward. Closer, a brick-back inserted where the distance will not permit of a brick in length. Closet, a small chamber or private room. Clout-nails, used for nailing clouts on the axle-trees of the carriage. Clove-hitch, two half-hitches round a spar or other rope. Clove-hook, an iron clasp, in two parts, moving upon the same pivot COA and overlapping one another, used for bending chain-sheets to the clews of sails. Clubbing, drifting down a current with an anchor out. Club-haul, to bring a vessel’s head round on the other tack, by letting go the lee anchor, and cutting or slipping the cable. Clue garnets, in navigation, tackles fixed to the clews or lower corners of the fore and main sail, to clew them up to the yards. Clustered column, a pier which con¬ sists of several columns or shafts clustered together. Clutch, an apparatus for engaging or disengaging two shafts: it consists of two pieces of metal formed so that when placed together, project¬ ing pieces on one (made to slide to and fro on the shaft, but turn with it) fit into recesses in the other, which is fixed on the driving shaft, so that the first being pulled back, its shaft will remain at rest. Cooking, in ship-building, uniting pieces of spar by means of tabular projections, formed by cutting away the solid of one piece into a hollow, so as to make a projection in the other in such a manner that they may correctly fit, the buts pre¬ venting the pieces from drawing asunder. Coal belongs to the third series of the Wernerian principle, viz. car¬ boniferous rocks, coal-measures, carboniferous limestone, and old red sandstone ; it is admitted to be of vegetable origin, and comprises —1. Lignites, a species of mineral charcoal or intermediate gradation from wood to coal; 2. Ordinary bituminous coal, of numerous va¬ rieties ; 3. Anthracite, found gene¬ rally in connection with the lowest portion of the third series, and sometimes in the primary rocks themselves. Coal, then, appears to have been formed of large vegetable masses, of considerable extent, in strata varying from a few inches to many feet in depth, the strata 111 COA COBALT. COC alternating with rocks wonder¬ fully uniform, and consisting, in most cases, of the following : sand¬ stone, slate clay or shale, fire-clay, ironstone, limestone, etc. Rocks are found participating of both clay and sandstone texture, greatly predominating. The coal-beds are indiscriminately accompanied by rocks either of sandstone or shale, which often rest upon fire-clay. It is in the shale accompanying the coal that the fossil impressions are so numerous; they are seldom found in the sandstones, or in the shales considerably distant from the coal-beds. The organic remains of coal formation consist of many shells of freshwater origin. The fossils, with land plants, occur in great abundance and variety, be¬ longing to extinct species, but bearing considerable analogy to those now growing only in tropical climates. These plants are mostly succulent, and are of enormous growth. Coal-gas , carburetted hydrogen ; coal- gas, when freed from the obnoxious foreign gas, may be propelled in streams out of small apertures, which, when lighted, from jets of flame, and are called gas-lights. Coal-tar, tar made from bituminous coal. Coamings, in ships, raised work round the hatches, to prevent water from getting down into the hold. Coat. Mast-coat is a piece of canvas tarred or painted, placed round a mast or bowsprit where it enters the deck. Coat, in building, a stratum or thick¬ ness of plaster-work. Cob (Cornish), to break or bruise: a cobber, a bruiser of tin. Cobbed ore is spoiled which is broken out of the solid large stones with sledges, and not put to water, being the best ore: the same as bing ore in the lead-mines. Cobalt (among miners), the damps of mines, so very fatal to the workmen. Cobalt. The ancient name for this mineral is not known. Theophras¬ tus mentions its use for staining glass. No cobalt has been disco¬ vered in any of the remains of ancient painting. It makes a co¬ lour, according to Vitruvius, be¬ tween scarlet and purple. In chemistry, a metal, when pure, of a white colour, inclining to bluish or steel gray: at the com¬ mon temperature its specific gra¬ vity is more than 8-5. Cobalt-blue is the name now appro¬ priated to the modern improved blue prepared with metallic cobalt, or its oxides, although it properly belongs to a class of pigments in¬ cluding Saxon blue, Dutch ultra- marine, Thenard’s blue, royal blue, Hungary blue, smalt, Zaffoe or enamel blue, and Dumont’s blue. These differ principally in their degrees of purity, from the nature of the earths with which they are compounded. Cobalt-green. There are two pig¬ ments of this denomination, the one a compound of cobalt-blue and chromic yellow, which partakes of the qualities of those pigments, and may be formed on the pallet. Coboose, the place where the victuals are cooked on board of merchant and passenger ships. Cob-wall, a wall built of unburnt clay mixed with straw. Cochineal is extremely rich in the finest red colouring matter, and has been long employed in scarlet dye¬ ing, and in the manufacture of carmine. Cochlea, a term used by the ancients to denote something of a spiral form; a spiral pump for raising water, etc. Cock, or stop-cock, a kind of valve contrived for the purpose of per¬ mitting or arresting at pleasure the flow of a liquid through a pipe. Cock-boat, a small boat used on rivers. Cock-pit, that part of a ship which is appropriated to the use of the sur¬ geon, being the place where the 312 COHESION. COC CO HI ISION. COH wounded are dressed: it is near the hatchway, and under the lower gun-deck. Cockle, the skiorl of the Swedes and the schorl of the Germans : a la¬ minated mineral substance of a blackish brown colour, like tin. Cocoa-wood, the heart of which is seldom sound, is much used in turnery. Coctilis, according to Pliny, a brick hardened by burning. Cock-water (among miners), a stream of water brought into a trough to wash away the sand from tin-ore. Cod-line, an eighteen-thread line. Co-efficients, in algebra, are numbers or letters prefixed to other letters or unknown quantities, into which they are supposed to be multiplied ; and therefore with such letters, or the quantities represented by them, making a product, or co-efficient product. Coigne, a corner; a wooden wedge. Coining (in the tin works), is the weighing and stamping the blocks of tin. Ccelum, according to Vitruvius, a soffit or ceiling. Ccenobium, anciently a monastery of monks or friars. Cofer, in Cornish mining, a small wooden*trough which receives the tin claused from its impurities or slime. Coffee-tree, a wood of alight greenish brown, close-grained, and small in stature, sometimes used by cabi¬ net-makers. Coffer, a deep panel in a ceiling; also applied to a casket for keeping jewels, and sometimes to a chest. Coffer-dam, a hollow space formed by a double range of piles, with clay rammed in between, for the purpose of constructing an en¬ trance lock to a canal, dock, or basin, or for the piers of a bridge. Coffin, in Cornish mining, old work¬ ings which were all worked open to grass, without any shafts, by dig¬ ging and casting up the thin stuff from one stall of boards to another. Coffin, a wooden case in which a dead body is placed, sometimes en¬ cased in lead : anciently, stone coffins were used for interment. Cog, the wooden tooth of a large wheel. Cog-teeth are formed of a different material from the body of the wheel: a timber tooth on a cog¬ wheel is one made of wood, when the teeth stand perpendicularly to the plane of the wheel. Cog-wheel, an iron wheel with wooden teeth or cogs. Cohesion of fluids. M. Monge and others assert that the phenomena of capillary tubes are referable to the cohesive attraction of the su¬ perficial particles only of the fluids employed, and that the surface must consequently be formed into curves of the nature of linteariae, which are supposed to be the re¬ sults of a uniform tension of a surface resisting the pressure of a fluid, either uniform or varying according to a given law. Cohesion, the attraction which takes place between the particles of bo¬ dies, denoting that force by which the particles firmly cohere. Cohesion and resistance of fluids, as examined by the force of torsion. Pressure does not augment the friction; on the contrary, the re¬ sistance is greater when the im¬ mersion is only partial. Greasing wood does not lessen the friction : the friction of oil is 17^ times as great as that of water. A part of the friction is proportional to the velocity : the constant part is al¬ most insensible. Thus a circle • 195 metre in diameter, turning in water with a velocity equal to’14 m. in 1", meets a resistance equivalent to a weight of 1 gramme acting on a lever of '143 m. The portion proportional to the velocity is e- quivalent to -042 gr. for a surface equal to twice such a circle moving in its own direction with a velocity of -01 m. Cohesive strength of materials. The 113 CO I COKE. COK force of cohesion may be defined to be that force by which the fibres or particles of a body resist sepa¬ ration, and is proportioned to the number of fibres in the body, or in the area of its section. Coiling, a serpentine winding of ropes, by which they occupy a small space, and are not liable to be entangled in working the sails of a ship. Coin, or quoin, the angle of a building; used also for the machicolation of a wall. Coke, charred pitcoal. The most va¬ luable of the secondary products of a gas establishment is coke. The best kind is obtainedfrom coalwhen carbonized in large masses, in ovens constructed on purpose. In a gas manufactory, the production of coke being of minor importance to the formation of good gas, it is ge¬ nerally of an inferior quality to that made in coke ovens, where it is the primary, and indeed sole object for which the coal is carbonized. But gas-coke is excellent for many pur¬ poses in the arts and manufactures, producing as clear a fire as that of the first quality, though it is neither so lasting nor so free from slag: for domestic use, however, it is unob¬ jectionable, and may be burnt both in the drawing-room and kitchen with economy and comfort. The distinguishing characters of good coke are, first, a clean, granu¬ lar fracture in any direction, with a pearly lustre, inclining to that exhibited by cast-iron. Secondly, density, or close proximity of its particles, which adhere together in masses, and specific gravity of 110, or rather higher. Thirdly, when exposed to a white heat, it con¬ sumes entirely away, without leav¬ ing either slag or ashes. It is invariably the case that the quality of the coke is inversely as that of the gas. The manufacturer must not expect to produce both of the best quality. The process by which the best gas is made gene¬ rally leaves the coke light, spongy, and friable, although an increase of quantity is gained ; for the simple reason, that the degree of heat and other circumstances required to form perfect coke must be entirely changed when gas of a high specific gravity is to be obtained. Thus large masses of coal exposed to a red heat in close vessels are acted upon by slow degrees, the external portionspreventing heat from pene¬ trating into the interior until most of the bituminous portions are given off in condensable vapour, or as charcoal and free hydrogen; the after products being light carbu- retted hydrogen, carbonic oxide, and carbonic-acid gases. The re¬ sidue is a carbon of a dense granular composition. Coke, as prepared for use in locomo¬ tive and other steam-engines, may be regarded as purified coal, or coal from which the extraneous matters not conducive to combustion have been expelled by the application of heat. It appears from experiments that the heating power of every description of fuel, whether coal, coke, wood, lignite, turf, or peat, is proportional to the quantity of carbon it contains, and that from 83 to 86 per cent, of this element enters into the composition of any given-weight of Newcastle, D urham, or Lancashire coal, the other in¬ gredients being hydrogen, azote, oxygen, and ashes. The exact pro¬ cess which takes place in the con¬ version of coal into coke is not yet thoroughly understood, although the result can he readily estimated, and is found to depend, to a con¬ siderable extent, upon the manner in which the process is performed. Thus, by coking in close ovens, "Welsh coal loses about 30 per cent, of its weight; but if the coking .be effected in uncovered heaps of coarse lumps, as it often is in the Welsh coal and iron districts (where abundance is allowed, as the excuse for extravagance and waste), the loss of weight is from 50 to 55 114 COL COLLAR. COL per cent. While the weiyht is thus diminished by coking in close ovens, the bulk is increased from 22 to 23 per cent. The rapid and complete combustion of the carbon which takes place in the burning of coke has the effect of preventing, to a considerable extent, the emis¬ sion of that palpable smoke which arises from the combustion of coal; and for this property coke was resorted to for use in locomotive engines, when the non-emission of smoke was imposed as one of the conditions upon which railway companies were empowered by Act of Parliament. The practical ad¬ vantages since found to be derived from the burning of coke instead of coal are, its greater power in evaporating water and producing steam, and the less rapid destruc¬ tion of the boiler which ensues from its employment. Colander, a vessel perforated at the bottom with little holes for the purpose of straining liquors. Cvlarin, the little frieze of the capital of the Tuscan and Doric column, placed between the astragal and the annulets. Colation, the act of straining liquor by passing it through a perforated vessel. Cold chisel, a piece of steel flattened and sharpened at one end, which is properly tempered, so that it may be used for cutting metal. Cold-harbour, an inn ; a shelter from the cold; a protection on the way- side for travellers benighted or benumbed. Cold short iron, iron in an impure state. Cold-water well and reservoir. To effect the condensation of steam, the water is very commonly raised, by means of the cold-water pump, from a reservoir or well. This ab¬ sorbs from the engine some portion of its power. Indeed, when the wells are deep, the quantity of power thus expended is so great, that the condensing system can no longer be judiciously applied. This may be known by the follow¬ ing investigation : Rule. —Multiply the weight of water, in pounds, by the feet through which it passes in a minute, and divide the product by 33,000 ; the quotient will exhibit, friction excluded, the horses’ power ex¬ pended. Example. —To condense 103°; Weight of cold water 10 lb. per gallon, at 62° of tem¬ perature, Engine, nominal power...4 horses. Water, per horse power...4 gals. Lift of do., or height raised, 230 feet per minute. „ 4X40 X230 HenCe 3 3,000 '= P° Wei '- Cold-water pump, the pump for sup¬ plying the water for condensation. Collapse, the falling together, as of the sides of a hollow vessel. Collar, the chain worn round the neck to which the Order of Knight¬ hood is attached. Also the part of the garment which surrounds the neck in ecclesiastical vestments. Collar, in ships, an eye in the end of the mandril next the chuck, in order to make the spindle run freely and exactly. Collar, a plate of metal screwed down upon the stuffing-box of a steam- engine, with a hole to allow the piston-rod to pass through. Collar of a shaft, the timber and boarding used to secure the upper¬ most part of a shaft in loose rub¬ ble from falling in. Collar-beam, a beam framed across and between two principal rafters. Colliery, the place where coal is dug, with its machinery and plant for discharging the water and raising the coal. Hence Collier, a person employed in a colliery; and Collier, a vessel for conveying coal. Collimator, an instrument for ascer¬ taining the horizontal point. Colliquefaction, the act of reducing different bodies into one mass by fusion. . 115 COL COLUMN. COL Collision, in mechanics. Whenever two bodies act on each other so as to change the direction of their relative motions, by means of any forces which preserve their activity undiminished at equal distances on every side, the relative velocities with which the bodies approach to or recede from each other will al¬ ways be equal at equal distances. Colliquation, smelting or dissolving anything by heat. Collumarium , anciently a well or opening formed at intervals in the channel of an aqueduct for pro¬ curing a free current of air along its course, and to facilitate the opera¬ tion of clearing away foul deposits left by the waters. Cologne earth is a native pigment, similar to the Vandyke brown in its uses and properties as a colour. Colonnade, a range of columns, whether attached or insulated, and supporting an entablature. Colosseum, aname given to the theatre of Vespasian, either from its mag¬ nitude or from its colossal statue of Nero; also the name of a fine building in the Regent’s Park. Colossus, a statue of gigantic dimen¬ sions, or very much beyond the proportions of nature. Colour. The term colour being used synonymously for pigment is the cause of much ambiguity, particu¬ larly when speaking of colours as sensible or in the abstract; it would be well, therefore, if the term pig¬ ment were alone used to denote the material colours of the pallet. Colouring, in painting, the art of dis¬ posing the tints, so as to produce either an imitation of the natural colours of the objects represented, or force and brightness of effect. Although a subject inferior to many others which the painter must study, this is yet of sufficient im¬ portance to employ a considerable share of his attention; and to excel in it, he must be well ac¬ quainted with that part of optics which has the nature of light and colours for its object. Light, how¬ ever simple and uncompounded it may appear, is nevertheless made up, as it were, of several distinct substances; and the number and quantity of component parts have been happily discovered by the moderns. Colourist, one who colours, and hence significantly, one who excels in giving the proper colour to his designs. Columbaria, or Columbary, a dove¬ cot; the holes left in w r alls for the insertion of pieces of timber; so called from resembling the niches of a pigeon-house. The niches of a mausoleum, made to receive the cineral urns, were likewise termed columbaria. The columbarium was a place of sepulture used for the ashes of the Romans, after the custom of burning the dead had been introduced among them. Columen, the term applied to the upright timbers of a roof, corre¬ sponding to the modern kingposts. Column, in architecture, a member of a cylindrical form, placed up¬ right for support of buildings, principally wrought in stone, and made decorative in conformity to the order and style of architectural composition. It consists of a base, a shaft or body, and a capital, and differs from the pilaster, which is square on the plan. Columns, in architecture, ac¬ cording to Vitruvius, were of the three orders. The proportions of Corinthian columns are in every respect, excepting their capitals, similar to those oflonic ; although their form is more graceful and proportionately more delicate, by reason of the greater height of the capitals; for Ionic capitals are a third part only of the lower dia¬ meter of the columns, whereas the Corinthian capital is equal in height to an entire diameter. The peculiar character of the ca¬ pitals, which admits of their being higher than those of Ionic co- 116 COM COMBUSTION. COM lumns by two-thirds of a diameter, gives beauty to them, by permitting an increase of the height without violating the laws of symmetry. In strictness, the shaft of a column consists of one entire piece ; but it is often composed of different pieces, so united as to have the appearance of one entire piece. It differs, in this respect, from a 'pillar, which primarily signifies a. pile, composed of small pieces. But the two things are unfortunately confounded; and a column, consisting of a single piece of timber, is called a pillar or pile. An erect or elevated structure, resembling a column in architec¬ ture ; as, the astronomical column at Paris, a kind of hollow tower, with a spiral ascent to the top; ynomonic column, a cylinder on which the hour of the day is indicated by the shadow of a style; military column, among the Romans ; triumphal column, etc. Column is also used to designate any body pressing perpendicularly on its base, and of the same dia¬ meter as its base ; as a column of water, air, or mercury. In the military art, a large body of troops drawn up in deep files, with a narrow front; as, a solid column. See, also, numbers of ships in a fleet following each other in order. In printing, a column signifies a division of a page; a perpendicular set of lines separated from another set of lines by a line or blank space. In manuscript books and papers, any separate perpendicular line or row of words or figures. A page may contain two or more columns; and, in arithmetic, many columns of figures may be added. The word column in botany is applied to the aggregate stamen of a plant when the filaments are united into a tube around the styles, as in the Malvaceous plants, which have been called Columni- ferce, i.e. column-bearers. The united stamens and styles of the plants of which the genus Orchis is the type, is called a column In conchology, the upright pillar in the centre of most of the uni¬ valve shells, from its semblance to a column, is called Columella. Combustion, a chemical process, in which two substances at least enter into combination, and heat and a new compound are the results. Thus, when antimony in powder, or copper in the form of thin leaf, is presented to chlorine, a combi¬ nation is instantly effected between these bodies, and a chloride of antimony or of copper is the result, attended at the moment of combi¬ nation with heat and light. It is usual to reckon five supporters of combustion, viz. oxygen, chlorine, iodine, bromine, and fluorine. Of these, the first is by far the most important. It is one of the con¬ stituents of the atmosphere and of water; it enters abundantly into the composition of most bodies in their natural state,and is altogether so important that without it no animal could live, no plant could grow, and, generally speaking, no flame could burn ; the other four supporters of combustion, as they are termed, would not support animal or vegetable life. Before the discovery of oxygen gas com¬ bustion was explained by sup¬ posing that all combustible bodies contained a certain principle called phlogiston, the presence of which enabled bodies to burn. It was further supposed that when a body burned, phlogiston was liberated, and that when a body lost phlogis¬ ton it ceased to be combustible; it was then said to be dephlogisti- cated. The heat and light which accompany combustion were attri¬ buted to the rapidity with which phlogiston was evolved. But according to this hypothesis, a combustible body having under¬ gone the process of combustion 117 COM COMBUSTION. COM ought to have lost weight, whereas it was found in many cases that the results of combustion were heavier than before combustion had taken place. The discovery of oxygen gas proved fatal to the phlogiston theory. Lavoisier burnt phosphorus in a jar of oxygen, and observed that much of the gas disappeared, and that the phos¬ phorus gained in weight; that the increase of the one was in the ratio of the decrease of the other. Iron wire burnt in oxygen gas gave a result equal to the wire employed, plus the weight of the oxygen that had disappeared. Mercury being confined in a vessel of oxygen, and exposed to the temperature of about 600°, the gas combined with the metal, and the resulting oxide being heated to about 90G°, was reconverted into oxygen gas and metallic mercury; the quantity of oxygen thus recovered answering precisely to that employed in the first instance to produce the oxida¬ tion. In ordinary cases of com¬ bustion the heat evolved does not depend upon the combustible, but upon the quantity of oxygen that enters into combination. Thus, ac¬ cording to Despretz, 1 lb. of oxygen, in combining respectively with hydrogen, charcoal, alcohol, etc., evolved in each case nearly the same amount of heat, each raising 29 lbs. of water from 32° to 212°. A given weight of different com¬ bustibles gives the comparative quantities of heat represented by the following figures :— lbs. of water. 1 lb. of pure charcoal raised ... 78 from 32° to 212° „ common wood charcoal . . 75 „ „ baked wood. . 36 „ „ „ wood, holding 20 per cent, of water ... 27 „ ,, „ bituminous coal 60 „ „ „ turf . . 25 to 30 „ „ ,, alcohol ... 63 „ „ „ oil, wax ... 90 „ „ ether .... 80 „ „ „ hydrogen . 236 „ „ The products of combustion in oxygen or its compounds form the three great classes of acids, alkalies, and oxides. When combustion is unintentional, or is the result of ignorance or carelessness, it is con¬ venient to call it spontaneous com¬ bustion. Thus we frequently hear of hayricks, etc., on fire; occa¬ sionally of carts loaded with quick¬ lime being burned by the rain falling upon the lime. There are also somewhat apocryphal accounts of coal in coal-yards being de¬ stroyed in like manner. But the most important instance of this class, as far as regards the preser¬ vation of Government establish¬ ments, is the combustion that infallibly and rapidly ensues when greasy hemp, flax, or cotton, is allowed to remain loosely heaped together, in any quantity, in a con¬ fined unventilated space. Full proof of this has been made by experiments in the dockyards; and there is much reason to attribute many fires in former days to care¬ lessness in the rope-walks and hemp-stores; in consequence of which, rigorous orders have been of late years issued as to the im¬ mediate disposal of loose oakum and hemp sweepings—all more or less greased or oiled. The very oil-rags used by engravers in clean¬ ing plates, when heaped together to any amount, will be consumed in a few hours. The combination in question seems to be within the oil and the oxygen of the atmosphere. Oil has always an affinity for oxygen; though, when the bulk of the former is considerable in pro¬ portion to the surface, the action is but feeble, and the results not ordinarily appreciable: but in the case of admixture of such fibrous vegetable bodies as hemp, flax, or cotton with oily matters, where the ratio of surface to solidity is great, and when the conditions for accumulating heat are favourable, 118 COM COMPARTMENT. COM —this accumulation soon produces ignition amongst such inflammable bodies as those just enumerated. Come. ‘ Come home said of an an¬ chor when it is broken from the ground, and drags. To ‘ come up ’ a rope or tackle, is to slack it off. Commandry, a religious house be¬ longing to a body of knights of the order of St. Bernard and St. Anthony. Commissure, the joins between two stones, in masonry. Common pitch, an old term still ap¬ plied by country workmen to a roof in which the length of the rafters is about three-fourths of the entire span. Common sewer of Rome : it was near the Senatorian bridge, and was 16 feet in diameter. Communication valves, the valves in a steam-pipe which connects two boilers to an engine, for cutting off the communication between either boiler and the engine. ! Communion table, a piece of church furniture usually placed near the wall of the east end of the chan¬ cel, and enclosed by rails, within which the clergyman stands to administer the Sacrament. Companion, a wooden covering over the staircase to a ship’s cabin. Compartition, the division or distri¬ bution of the ground-plan of an edifice into its various apartments. Compartment of the streets within a city. According to Palladio, re¬ gard must be always had to the temperature of the air, and also to the region of heaven, or the cli¬ mate under which the place is situated ; because where the air is cold or temperate, there the streets ought to be made large and noble, since thereby the city will become more wholesome, convenient, and ' beautiful: it being certain that the less piercing, and the freer the air is, the less will it offend the head; and therefore the more a _ town is situated in a cold place, or in a piercing air, and the houses are high, the longer ought the streets to be made, that they may be vi¬ sited by the sun in every part. Compartment, a division or separate part of a general design. Compass (Harris’s magneto-electric). The inventor’s object, in the appli¬ cation of his discovery of the stea¬ dying action of the copper ring, “ is the combination of great sensi¬ tiveness with stability and simpli¬ city of construction ; so that w'hile the needle is free to obey the mag¬ netic force of the earth in the most perfect way, it yet remains tran¬ quil amidst the disturbing motions to which a ship is exposed; and this stability is obtained without the aid of friction or other me¬ chanical impediment, which often produce an apparent steadiness or rather sluggishness of the com¬ pass (arising from indifference to motion), at the expense of ac¬ curacy. “ When the horizontal position of the card is disturbed by any alteration of dip incidental to a change of latitude, it is to be cor¬ rected by moving the silver sliders on the needle. “ Should the compass be out of use, care must be taken to let the needle hang freely in the meridian ; and if put into a store-room, or otherwise set by, the card and needle should be removed alto¬ gether, and placed with the needle downward in the shallow' box pro¬ vided for it,—the north point being on that part of the keeper marked with a cross, thus x . A good compass is liable to deterioration and damage when stowed aw r av without regard to its magnetic properties, and without due care being taken to preserve the agate and the point of suspension in a perfect state.” Compasses, an instrument with tw T o long legs, working on a centre pin at one extremity; used for draw¬ ing circles, measuring distances, setting out wmrk, etc. 119 COM COMPOSITION. Compass-headed, in ancient architec¬ ture, circular. Compass-plane, in joinery, a tool si¬ milar to the smoothing-plane in size and shape, but the sole is convex, and the convexity is in the direction of the length of the plane. The use of the compass- plane is to form a concave cylin¬ drical surface, when the wood to be wrought upon is bent with the fibres in the direction of the curve, which is in a plane surface perpen¬ dicular to the axis of the cylinder: consequently, compass-planes must be of various sizes, in order to accommodate different diameters. Compass-roof, a roof in which the braces of the timbers are inclined so as to form a sort of arch. Compass-saw, in joinery, a tool for cutting the surfaces of wood into curved surfaces : for this purpose it is narrow, without a back, thicker on the cutting edge, as the teeth have no set : the plate is about an inch broad, next to the handle, and diminishes to about one quar¬ ter of an inch at the other extre¬ mity; there are about five teeth in the inch: the handle is single. Compass-window, a bay window, or oriel. Complement (the) of an arch or angle is what it wants of 90 degrees -. thus the complement of 50° is 40°, and the complement of 40° is 50°. Compluvium (Latin), the interval be¬ tween the roofs of porticoes which surround the cavacdium. The rain was admitted through this opening and fell upon the area below, which was termed by some authors the impluvium. Composite Order: by some considered not a distinct order, but a variety of the Corinthian. For its height and proportion, see Architecture, Orders. Care must be taken in Compo¬ site as well as in Corinthian capi¬ tals, that the feet of the lower leaves do not project beyond the upper part of the column, as at COM St. Carlo, in the Corso at Rome, and at the Banqueting-house in London ; for nothing can be uglier. Neither are these leaves, as they mount, to bend forwards, as in many of the antiques, and in some modern buildings, because they then hide a considerable part of the upper row of leaves, and give a stunted disagreeable form to the whole capital. The different divi¬ sions of the acanthus-leaf, and bunches of olive or parsley which compose the total of each leaf, must be firmly marked, and massed in a very distinct manner: the stems that spring from between the upper leaves are to be kept low upon the vase of the capital, while rising between the leaves, then spring gradually forwards, to form the different volutes; and the ornaments, which sometimes are used to adorn the sides of the angular volutes, are never to pro¬ ject beyond the fillets between which they are confined. Composition of motion, in mechanics, an assemblage of several directions of motion resulting from several powers acting in different though not in opposite directions. Composition, in painting, is a tasteful and proper distribution of the ob¬ jects of a picture, in grouping, in the attitudes, in the draperies and the management of the back¬ ground. In architecture, the seve¬ ral parts which constitute a temple ought to be subject to the laws of symmetry, the principles of which should be familiar to all who pro¬ fess the science of architecture. Symmetry results from proportion, which, in the Greek language, is termed analogy. Proportion is the commensuration of the various constituent parts with the whole; in the existence of which, sym¬ metry is found to consist; for no building can possess the attributes of composition in which symmetry and proportion are disregarded, nor unless there exists that perfect 120 CONCRETE. COM conformation of parts which may be observed in a well-formed hu¬ man being. Compound arch, according to Profes¬ sor Willis, an arch which has the archivolt moulded or formed into a series of square recesses and angles, on the principle that “ it may be resolved into a number of concen¬ tric archways successively placed within and behind each other.” Compound pier, a term applied to a clustered column. Compression, the result of pressing or squeezing matter so as to set its parts nearer to each other, and to make it occupy less space. Computation, the method of esti¬ mating time, weights, measures, etc. Concamerate, to arch over. Concameratio, arched work. Concave, a term denoting the curvi¬ linear vacuity of hollow bodies. Concentric, having a common centre ; as concentric circles, ellipses, etc. Concha, according to Dr. Whewell, a term for the concave ribless sur¬ face of a vault. Conclave, a private or secret council; an inner room for meeting pri¬ vately. Concluding line, a small line leading through the centre of the steps of a rope or Jacob’s ladder. Concrete, a composition of lime, sand, pebbles, or other materials, now commonly used for the foun¬ dations of buildings. The general employment of the mixture of lime and gravel, commonly known hv the name of concrete, in all foundations where, from the nature of the soil, precautions against partial settlements appear neces¬ sary, and the great probability of an extension of its use in situa¬ tions where the materials of which it is composed are easily and cheaply procured, must of course render it a subject of great inte¬ rest to the engineer. Much va- ■ luable information on this subject will he found in a prize essay by CON Mr. G. Godwin, published in the * Transactions of the Institute of British Architects.’ In this essay, many instances are brought for¬ ward of the employment by the ancients of a mixture analogous to concrete, both for foundations and for walls. Several cases are also mentioned in which, of late years, it has been used advanta¬ geously for foundations, by some of the most distinguished architects and civil engineers. In these lat¬ ter instances, the proportion of the ingredients varies from one of lime and two of gravel, to one of lime and twelve of gravel,—the lime being in most cases Dorking lime, and the gravel, Thames ballast. The proportion, however, most commonly used now, in and about London, is one of lime to seven of ballast; though, from experiments made at the building of the West¬ minster New Bridewell, it would appear that one of lime to eight of ballast made the most perfect con¬ cretion. Concrete, compounded solely of lime and screened stones, will never assume a consistence at all equal to that of which sand forms a part. The north wing of Buck¬ ingham Palace affords an instance of this : it was first erected on a mass of concrete composed of lime and stones, and when subsequent alterations made it necessary to take down the building and remove the foundation, this was found not to have concreted into a mass. Mr. Godwin states, as the result of several experiments, that two parts of stones and one of sand, with sufficient lime (dependent on the quality of the material) to make good mortar with the latter, formed the best concrete. As the quality of the concrete depends, therefore, on the goodness of the mortar composed of the lime and sand, and as this must vary with the quality of the lime, no fixed proportions can of course he laid 121 G CON CONCRETE. CON down which will suit every case. The proportions must be deter¬ mined by experiment; but in no case should the quantity of sand be less than double that of the lime. The best mode of compounding the concrete is to thoroughly mix the lime, previously ground, with the ballast in a dry state; sufficient water being then thrown over it to effect a perfect mixture, it should be turned over at least twice with shovels, and then wheeled away instantly for use. In some cases, where a great quantity of concrete has to be used, it has been found advisable to employ a pug-mill to mix the ingredients : in every case it should be used hot. With regard to the quantity of water that should be employed in forming concrete, there is some difference of opinion ; but as it is usually desirable that the mass should set as rapidly as possible, it is not advisable to use more water than is necessary to bring about a perfect mixture of the ingredients. A great change of bulk takes place in the ingredients of concrete when mixed together: a cubic yard of ballast, with the due proportion of lime and water, will not make a cubic yard of concrete. Mr. God¬ win,from several experiments made with Thames ballast, concludes that the diminution is about one-fifth. To form a cubic yard, therefore, of concrete, the proportion of lime being J-th of the quantity of ballast, it requires about 30 cubic feet of ballast, and 3f cubic feet of ground lime, with sufficient water to effect the admixture. An expansion takes place in the concrete during the slaking of the lime, of which an important use has been made in the underpinning of walls : the amount of this ex¬ pansion has been found to be about fths of an inch to every foot in height; and the size thus gained, the concrete never loses. The examples from which the above rules are deduced are princi¬ pally of buildings erected in or about London ; the lime used is chiefly from Dorking, and the bal¬ last from the Thames. It is very desirable that a more extended collection of facts should be made, that the proportions of the mate¬ rials, when other limes and gravels are used, should be stated, in order that some certain rules may be laid down by which the employment of concrete may be regulated under the various circumstances which continually present themselves in practice. The Dorking and Hailing limes are slightly hydraulic. Will com¬ mon limes, such as chalk, and common stone-lime, answer for forming foundations of concrete, where the soil, although damp, is not exposed to running water ? Is it possible, even with hydraulic lime, to form a mass of concrete in running water ? If common lime will not answer, may it not be made efficient by a slight mixture of cement ? These, and questions similar to these, are of great in¬ terest ; and facts which elucidate them will be valuable contributions to the stock of knowledge on this subject. It is a question for consideration, whether a great variety of sizes in the materials used would not form the most solid as well as the hardest wall. The walls of the.fortress of Ciudad Rodrigo, in Spain, are of concrete. The marks of the boards which retained the semi-fluid mat¬ ter in their construction are every¬ where perfectly visible; and besides sand and gravel, there are every¬ where large quantities of round boulder-stones in the walls, from 4 to 6 inches in diameter, procured from the ground around the city, which is everywhere covered with them. Condensation , the conversion of va¬ pour into water by cold. 122 CONDUCTION, ELECTRICAL. CON Condenser, in steam-engines, the ves¬ sel connected with the exhaust-port of the cylinder of a low-pressure engine, and also with the air-pump, by a passage at the bottom fitted by the foot-valve of the pump i it receives the steam from the cylin¬ der, and condenses it by a jet of cold water, thus forming a vacuum for the return stroke: the water, air, etc., are then drawn off by the air-pump, and discharged into the hot well. Conditorium, a secret place; a sepul¬ chre ; a vault. Conduction, electrical, a series of phenomena in electricity, giving origin to a classification of sub¬ stances as conductors of electricity. The substances which properly come under this conducting or non¬ electric class are principally as fol¬ lows :— LIST OF ELECTRICAL CONDUCTORS. Every metallic substance known. Well-burned charcoal. Plumbago. Concentrated and diluted acids, and saline fluids. Water, and moist vegetable matter. Living animal matter. Flame — smoke — steam. The distinctive difference in the conducting and non - conducting property of bodies may he readily illustrated in the following way :— Excite a glass tube and wire, and bring the ball of the wire into contact with any of the electrics, as a rod of glass, a stick of sealing- wax, or brimstone rendered per¬ fectly dry : the attractive power of the ball and wire, together with the tube, will not be in any sensi¬ ble degree impaired. Let the elec¬ trified ball now touch the walls of i the room or other conducting sub¬ stance communicating with the ground ; the attractive power will instantly vanish. It is evident from these facts that all electric substances are non¬ conductors or insulators, as they are appropriately termed; whilst, CON on the other hand, non-electric substances are transmitters or con¬ ductors of electrical action. When, therefore, any conducting sub¬ stance is placed on an electrical support, such as a rod of glass or shell-lac, it is considered to be insulated, and is termed an insu¬ lated conductor; when electrified by contact with any excited or other electrified body, it is said to be charged. The electrical charge thus communicated to an insulated conductor appears to be collected about its surface, and to he rather dependent on that than on the solid content. Thus, if two metallic spheres or cylinders, the one solid, the other hollow and extremely light, be suspended by silk lines, or placed on dry insu¬ lating supports, and be charged by contacts with an excited tube, the attractive energy of each upon any liglrt substance presented to it will be found quite alike in each. In this experiment the insulators must be very dry and perfect. The best insulating substances are of the vitreous and resinous class, such as shell-lac, brimstone, dry glass rods, vitrified and crys¬ talline bodies : to these may be added silk. The best conducting substances are principally metallic bodies, sa- I line fluids, and common charcoal. It should, however, he here un¬ derstood, that modern researches, especially those of Faraday, lead us to conclude that there are really no substances which perfectly con¬ duct or perfectly obstruct electrical action. The insulating and con¬ ducting power is, in fact, a differ¬ ence of degree only: still, the ex¬ treme differences are so great, that if classed in relation to such dif¬ ferences, those at the extremes of the series admit of being considered the one as insulators, the other as conductors; whilst the interme¬ diate terms are made up of sub¬ stances which may be considered g 2 123 CON CONICAL as imperfect, taken as either. Con¬ versely, every substance is capable of excitation by friction; yet the differences in this respect are so great as to admit of some bodies being called electrics and others non-electrics, with an intermediate class between these extremes, which may be termed imperfect electrics. Series of conductors and insu¬ lators. —Metals and concentrated acids are found at the conducting extremity of such a series,—shell- lac, brimstone, all vitreous and resinous bodies, at the other or electric extremity ; whilst the im¬ perfect or intermediate substances comprise such matter as common earth and stones, dry chalk, mar¬ ble, porcelain, paper, and alkaline matter. The attractive power evinced by any electrical body in a state of excitation,' although the first and usually the most evident electrical effect, is yet not the only force which seems to result from this curious condition of common mat¬ ter. On a closer examination of the phenomena, a new class of facts present themselves, of re¬ markable interest. If the excita¬ tion be considerable, and the at¬ tracted body insulated, it will, after being drawn into contact with the electrified substance, rebound from it with great violence, as if repelled by some new power, and will not be again attracted until it has had conducting communication with the earth, or some other mass of matter capable of reducing it to its original condition before the con¬ tact. Conduit , a structure forming a reser¬ voir for water, and from which it is drawn for use. Cone, a solid body having a circular base, and its other extremity ter¬ minating in a single point or vertex. Cones are either right or oblique. Cone-plate , a strong plate of cast iron fixed vertically to the bed of a lathe, POINTS. CON with a conical hole in it, to form a support for the end of a shaft which it is required to bore. Confessional , a recess or seat in which the priest sits to hear the confes¬ sions of penitents. Conge, another name for the echinus or quarter-round, as also for the cavetto : the former is called the swelling conge, the latter the hol¬ low conge. Conic sections, the curves formed by the intersection of a circular cone and a plane ; the former being either oblique or right. Conical points, in turnery, the cones fixed in the pillars for supporting the body to be turned : that on the right hand is called the fore centre, and that on the left hand, the back centre. Conissinet, the stone which crowns a pier, or that lies immediately over the capital of the impost, and under the sweep. The bed of it is level below, and curved above, receiving the first rise or spring of the arch or vault. Conisterium, an apartment in the pa¬ laestra, in which sand was kept for sprinkling the athletae, after they had been anointed. Connecting-rods, in locomotive en¬ gines, the strong iron rods which connect the piston to the driving- wheel axle, and thus give motion to all the machinery. Connecting-rods, in locomotive en¬ gines, outside or side rods, those which connect together the wheels of good engines. They are seen outside the wheels, making an ir¬ regular forward motion, like water¬ men rowing a boat. By connect¬ ing the wheels together, one pair cannot slip without the others, and the greatest practicable adhe¬ sion is thus obtained. Connecting-rod straps, in locomotive engines, strong pieces of iron bent like the letter c, which fit the ends of the connecting-rod, and into which the axle-bearing is fitted in two parts. They are attached 124 CON CONSERVATORY. CON to their respective ends of the rod by keys and cotters, which are taken out, and the half of the bearing also, when a connecting- rod has to be put on. The strap and half-bearing are then brought over the axle or cross-head, the other half-bearing put into the strap, the end of the rod brought up against the bearing, and se¬ cured by the keys and cotters. Taking off a rod is of course the reverse of putting one on. Connecting-rod bearings, in locomo¬ tive engines, the gun-metal or composition metal bearings fitted into the straps, to suit the parti¬ cular part they are to work on. Conning, directing the helmsman in steering a vessel. Conservatory, a superior kind of greenhouse, for exotic plants, is made with beds of the finest composts, into which plants are removed for culture and preser¬ vation. Its construction is more capacious than the ordinary green¬ house, and it is furnished in a superior style, provided with a free admission of light, and, in addition, with flues or boiling- water pipes to raise the tempera¬ ture when necessary, and also contrivances for the introduction of fresh air. Consistory court, a spiritual court, formerly held in the nave of the cathedral church. Console, a bracket or truss, mostly with scrolls or volutes at the two ends, of unequal size and contrasted, but connected by a flowing line from the back of the upper one to the inner convolving face of the lower. Constant white, permanent white, or barytic white, is a sulphate of ba¬ rytes, and, when well prepared and free from acid, is one of the best whites for water-painting, being of superior body in water, but desti¬ tute of this quality in oil. Construction, in architecture: for this the chief requisites are, magnitude and strength,and the art of distri- buting the different forces and strains of the parts and materials of a building in so scientific a manner as to avoid failure and to insure durability. Continuous imposts, according to Pro¬ fessor Willis, are the mouldings of an arch which are continued with¬ out interruption down the uprights to the ground or base, the impost point having no mark or distinc¬ tion of any kind. Contouring (surveying altitudes and levels). This term is applied to the outline of any figure, and con¬ sequently to that of any section of a solid body; but when used pro¬ fessionally, in connection with the forms of ground, or of works of defence, the outline of a horizontal section of the ground, or works, is alone to be understood by it. When the forms of ground, or works, are described by contours, or horizontal sections, these sec¬ tions are taken at some fixed vertical interval from each other, suited to the scale of the drawing, or to the subject in hand; and the distance of each, above or below some assumed plane of compari¬ son, is given in figures at the most convenient places on the plan. When the scale of the drawing is about 100 feet to an inch, 2 or 3 feet will be found a convenient vertical interval between the con¬ tours ; and however large the scale of the plan, it will scarcely be found necessary to obtain contours with a less vertical interval than 2 feet. If the scale of the plan be about 250 feet to an inch, or the ordinary special survey scale of 4 chains to an inch, 5 feet will prove a convenient vertical interval; and with a horizontal scale of from 500 to 100 feet per inch, 10 feet may be taken as the vertical interval. In tracing and surveying the contours of ground, the following process may be adopted : com¬ plete the survey of the occupation of the ground, the streams, etc., CON COPPER. COR and determine carefully the alti¬ tudes of the trigonometrical points employed above the intended place of comparison; take an accurate trace from the plot of one of the triangles, which, if the distances between the trigonometrical points are properly proportioned to the scale of the plan, will generally he a convenient piece in point of size to contour; take this trace to the ground, and find upon the ground, and mark upon the trace the points where each of the intended con¬ tours will cut the boundary lines of the triangle. Contraction, the effect of cold upon a warm body, causing a diminution in its size by the particles ap¬ proaching each other. Conti ainure, an out-wall built about the wall of a city or fortification. Convent, a building appropriated to religious persons. Convocation and Convocalors, or par¬ liament of tinners. All Stannary laws are enacted by the several convocations. Cooper, one who makes barrels. About a.d. 70, according to Pliny, cooperage was first used by the Romans, and casks superseded wine-skins—the old bottles into which it was not prudent to put new wine. The artof puttingpieces of wood together in the formation of vessels for holding liquid had its rise amongst the dwellers at the foot of the Alps, and shortly" after it was probably introduced into Britain. The tiykt-cooper, as also the wet-cooper, makes casks for hold¬ ing liquid, and is the representative of the first inventor. The dry- cooper makes casks for goods not in a liquid state,such as flour, rice, dried fruits, sugar, etc. The white- cooper makes butter-casks, tubs, pails, and churns, and combines in some measure the skill and know¬ ledge of his two elder brothers. A cooper-in-general is seldom a skilled workman, but a jobber and mender of other men’s work. Cooper tor ium, the roof of a build- ing. Co-ordinates, in the theory of curves, any absciss and its corresponding ordinate. Cope (to), to jut out as a wall. Cope (to), to cover over an arch. Coping, the reversing course of a wall, either flat or sloping on the upper surface, to throw off water. Coppe-house, anciently a tool-house. Copper, one of the six primitive metals, and the most ductile and malleable after gold and silver. Of this metal and lapis calaminaris is made brass, which is comparatively a modern invention. Copper green (colour); the appella¬ tion of a class rather than of an in¬ dividual pigment, under which are comprehended verdigris, verditer, malachite, mineral green, green bice, Scheele’s green, Schweinfurt or Vienna green, Hungary green, emerald green, true Brunswick green, lake green, mountain green, African green,French green, Saxon green, Persian green, patent green, marine green, Olympian green, etc. The general characteristic of these greens is brightness of colour, well suited to the purposes of house¬ painting, but not adapted to the modesty of nature in fine art. Coral wood is of a fine red colour, hard, and polishable. Corbel, or Corbeille, a short piece of timber or stone let into a wall half its length or more, as the burthen superimposed may require, to carry a weight above it, and projecting from the general face of the work: it is carved in various fanciful ways; the commonest form is, however, that of an ogee. Corbel, in Gothic architecture, a pro¬ jecting stone or piece of timber which supports a superincumbent weight. Corbel-table , a cornice supported by corbels. Corbie steps, steps up the side of a gable, found in old houses in Flan¬ ders, Holland, etc. 126 CORONA. COR Cordon, the edge of stone on the out¬ side of a building. Core, with the Cornish tinmen, is a division of time and labour. Corinthian Order. The three columns in the Campo Yaccino, supposed remains of the temple of Jupiter Stator, are generally allowed to be the most perfect models of the Corinthian order amongst the an¬ tiques at Rome. Palladio, in his fourth book, where he gives the whole profile at large, acknow¬ ledges that he never had seen any work better executed, or more deli¬ cately finished; that its parts are beautifully formed, well-propor¬ tioned, and skilfully combined ; all which last qualities are certainly signified by his benissimo intesi. With these favourable senti¬ ments, it is extraordinary that, in his design of the Corinthian order, he should have so very considerably deviated from this excellent origi¬ nal as scarcely to leave the smallest shadow of resemblance. Vignola, in his Corinthian pro¬ file, has chiefly imitated the above- mentioned fragment, and the inte¬ rior order of the Pantheon, another very perfect model. His compo¬ sition is uncommonly beautiful, and, without dispute, superior to that of any other master: he art¬ fully collected all the perfections of his originals, and formed a whole far preferable to either of them. Corinthian Brass. Gold, silver, and copper, casually mixed together at the burning of the city of Corinth, there being a great many statues and vessels melted down and so embodied. Corner-stones, in architecture, the two stones which stand one in each joint of the chimney. Corneus, a kind of tin ore, found in black columns, with irregular sides, and terminating in prisms. Cornice, the projection, consisting of several members, which crowns or fini-hes an entablature, or the body or part to which it is annexed. The COR cornice used on a pedestal is called the cap of the pedestal. Cornish engine, a single-acting beam engine, used for raising water ; the steam is worked very expansively, and used for the down-stroke only, to raise an immense weight, fas¬ tened to the pump-rod, at the end of the beam : the steam having acted for the down-stroke, and the entrance-valve being closed, a com¬ munication is formed between the top and bottom of the cylinder, by lifting a valve in the steam passage, called an equilibrium valve ; the pressures on the piston are thus equalized, and the weight acts to force the water up, and raise the piston. Cornucopia, or horn of plenty; among architects, painters, etc., it is repre¬ sented under the figure of a large horn, out of which issue fruit, flowers, etc. Corollary, an inference or deduction. Coromandel wood, the produce of Ceylon and the coast of India, is shipped in logs and planks from Bombay and Madras ; it is of a red hazel-brown colour, handsome for furniture wood, and turns well. Corona, the members constituting the uppermost of the three divisions of the entablature of a portico, or any other building in which columns are introduced ; this division is termed cornice. Corona, that flat, square, and massy member of a cornice, more usually called the drip or larmier, whose situation is between the cymatium above and the bed-moulding below; its use is to carry the water drop by drop from the building. Corporax cloth, a linen cloth or nap¬ kin spread upon the altar, on which the host and chalice are placed at the mass in the Catholic service. Corpse-gate, a covered place at the entrance to a churchyard, intended to shelter the corpse and mourners from rain. Correggio (Antonio Allegri); of the Lombard school he acquired the art I 127 COR COTTON. of modelling. His early style was acquired probably from Andrea Mantegna. Corridor, a gallery or open communi¬ cation to the different apartments of a house. Cori'ugated Iron, a design for the strength of iron beams or girders, in the employment of corrugated sheet iron. This was the subject of a patent, granted in 1848 to Mr. J. H. Porter, “ for an improved mode of applying corrugated iron in the formation of fire-proof floors, roofs, and other structures.” Corsa, the name given by Vitruvius to a platband or square fascia whose height is more than its projecture. Cortile, a small court enclosed by the divisions or appurtenances of a | building. Cords, in the middle ages, a court surrounded by edifices. Corgceum, a room similar to a tennis- court. Cosecant of an arch, the complement of another to 90 degrees. Costean pits , in Cornish mining, are shallow' pitssunk to trace orfindtin. Costeaning, in mining, the discover¬ ing of lodes by sinking pits in their vicinity, and drawing transversely to their supposed direction. Cot, in nautical phraseology, a bed- frame suspended from the beams of the ship, or otherwise. Cotangent, is the tangent of any com- plemental arch, or what the arch wants of a quadrant or 90 degrees. Colton, a white W'oolly or downy substance, found in a brown bud, produced by a shrub, the leaves of w'hich resemble those of the syca¬ more-tree. The bud, w'hich grows as large as a pigeon’s egg, turns black when ripe, and divides at top into three parts ; the cotton is as white as snow, and with the heat of the sun swells to the size of a pullet’s egg. Scripture speaks of cotton. Cotton manufactures and trade. Cot¬ ton was woven by the Hindoos and Chinese many centuries before the cou Christian era. The Egyptians are supposed to have imported woven cotton before the plant had begun to be cultivated in their country, and the Romans received woven cotton from India long before the cotton-plant was know n in Europe. The extension of the manufacture of it has now' become enormous. The export of cotton goods from England, in 1846, was .£25,600,693 in value. The distinctive names by which cotton is known in commerce are mostly derived from the countries which produce it; the exceptions are, sea-island cotton, and upland cotton. The former of these was first cultivated in the low sandy islands near the coastof Charleston, in America, while the latter is grown in the inner or upland country. The sea-island cotton is the finest of the several varieties. The upland is often called Bowed Cotton. The spinning of cotton into the form of yarn or thread requires many preparatory processes; but the inventions and improvements in machinery that have been ef¬ fected in recent years have rendered the process simple and of great national value. Cotton and Calico printing, the art of staining woven fabrics of cotton with various figures and colours. Cotton, gun, is prepared with cotton w'ool, and explodes at 400° Fahr. Gunpowder explodes at 600°. Couched, laid close, as in a stratum. Couissinet. (See Conissinet.) Coulisse, any piece of timber which has grooves in it; also pieces of wood which hold the floodgates in a sluice. Counter, that part of a vessel between the bottom of the stern and the wing transom and buttock. Counterfort, a pier, buttress, or ob¬ lique wall, built up agaiust a wall to strengthen and support it. Counter-gauge, in carpentry,a method of measuring joints by transferring 128 COU COUNTRY RESIDENCES. COU the breadth of a mortise to the place on another timber where the tenon is to be made. Counter-lath, in tiling, a lath placed by the eye. Counterpoise, any weight which, placed in opposition to another weight, produces an equilibrium ; but it is more commonly used to denote the weight used in the Ro¬ man balance, or steelyard. Countersinks, in joinery, are bits for widening the upper part of a hole in wood or iron, for the head of a screw or pin, and have a conical head. Those for wood have one cutter in the conic surface, and I have the cutting edge more remote from the axis of the cone than any other part of the surface. Coun¬ tersinks for brass have eleven or twelve cutters round the conic sur- I face, so that the horizontal section represents a circular saw. These are called rose-countersinks. The conic angle at the vertex is about 1 90 degrees. Countersinks for iron have two cutting edges, forming an obtuse angle. Counterview, in painting, a contrast or situation in which two things illustrate or set off each other. Counters, in ships, two parts of a ship called the upper and lower counter. Count-house, a reckoning-house, in Derbyshire; a house or room on the mine used for keeping accounts of the products, etc. Country residences. There are im¬ portant advantages which deserve to be brought into notice, whether for comfort and convenience, for gratifying taste or fashion. Addi¬ tional rooms appropriated for new purposes are often requisite. For¬ merly a gallery,although there were no works of art to fill it, was a ne¬ cessary part of a mansion ; of late years, tire billiard-room and tbe conservatory enter into the arrange¬ ments of an architect; and a suit of well-planned nursery-room shave been made a necessary part of the plan of a country mansion. The gallery is again about to resume its importance, and perhaps we may hereafter imitate the Romans in having covered walks contiguous to the house, in order to enjoy fresh air in the many rainy and snowy days at a country residence in an English winter. The irregu¬ lar style admits of such additions, and loses nothing of the picturesque effect. The exterior decorations of terraces, parterres, stairs of com¬ munication, and different gardens filled with groups of the many flowering shrubs and plants, are ad¬ mirably in harmony with this style of architecture. While we thus decorate closely around the house, it becomes less necessary to sacri¬ fice so much to the park. The masonry of such irregular archi¬ tecture requires not the expen¬ sive labour bestowed on a Grecian or Roman mansion. The whole should be in rough rubble-work, excepting the parapets, the corners, the windows, and doors. Many very good designs of castellated dwellings have been, in the execu¬ tion, deprived of their effect, by being built of smooth, hewn free¬ stone. If circular or square tow'ers are introduced in a composition of the irregular style, they should, in every case, be of great dimensions, as much for their being applied to useful rooms, as to produce that grandeur of appearance which bulk in towers always gives. The Country-seats of the Ita¬ lians have been copied by most civi¬ lized nations of Europe ; celebrated by poets, visited and admired by travellers : they have not, however, been described or represented as they deserve. They are so ar¬ ranged as to produce the best effect, and advantage of the nature of the site has been taken with admirable skill. The regularities of the gardens accompany the de¬ coration, and support the architec¬ ture. (See Parker’s ‘ Villa Rus- tica,’ recently published.) g 3 129 COU COUPLINGS. COW Couple-close, a pair of spars of a roof; also used by heralds as a diminu¬ tive of the chevron. Coupled columns. When, from the extent between columns sometimes necessary for the introduction of doors, windows, niches, or other decorations, neither the eustylos nor the diastylos intercolumniation can be used, coupled columns are frequently introduced. In this case two sistylos intercolumniations are used; the column which would otherwise occupy the middle of the space being brought to the distance of only half a diameter (or suffi¬ cient room for the projection of the capitals) from the extreme column. The middle space will then be three diameters and a half. This species has been called araso- sistylos. When buildings are small, the intercolumniations will not re¬ quire such particular attention to the foregoing rules, for columns should never be placed nearer to each other than three feet, which will allow for the easy passage of a bulky person. j Coupling , in machinery, is the name given to various arrangements by which the parts of a machine may be connected or disconnected at pleasure, or by which a machine may be disengaged from, or re¬ engaged with, a revolving wheel or shaft, through which it receives motion from a steam-engine, water¬ wheel, or other prime mover. Couplings, in inill-wmrk: it is fre¬ quently necessary to convey motion much farther than would be prac¬ ticable by any one shaft, and there¬ fore often requisite to connect two or more shafts together. These connections are denominated cou¬ plings, and may be divided into two classes: 1st, Those having two bearings ; 2ndly, Those having one bearing. Couplings having two bearings have been long in use, and before those having one bear¬ ing, and are generally more simple in their construction. Coupling-box, a metal box for joining the ends of two shafts, so that they may revolve together. Course, a continuous range of stones or bricks, of uniform height, in the wall of a building. Course, in Cornish mining, is a tin or copper course; a phrase for working of the lode. Courses, sails that hang from a ship’s lower yards : the fore-sail is called the fore-course, and the main-sail the main-course. Courts of Justice: there were in Rome twelve halls or courts of justice, where causes were heard and tried : they were adorned with statues, fine columns, and porticoes with double rows of columns. Cove, a cave, a recess; any kind of concave moulding; the concavity of an arch or of a ceiling. Coved ceiling, the upper surface of an apartment formed in an arched or coved shape at its junction with the side walls. Covenants of the Old and New Testa¬ ment (The Two), in the Table of Symbols of the early ages, are re¬ presented by the wheel in the middle of a wffieel. Ezek. i. 16. Cover, in slating, the part of the slate that is hidden; the exposed part being called the margin. Cover-way, in roofing, the recess or internal augle left to receive the covering. Cover, a turret or cupola on the roof of a hall or kitchen, pierced at the sides to let out smoke or steam. Covie or Covey, a pantry. Coving, the exterior projection of the upper parts of a building beyond the limits of the ground-plan. Coving, a term applied to houses, etc., that project over the ground-plot. Coving of a fireplace, the vertical sides, inclining backwards and in¬ wards, for the purpose of reflecting the heat. Cowl, a cover for the top of a chim¬ ney, made to turn round by the wind, and used to facilitate the escape of smoke. 130 cox CRANK. CRE Cowner, an arch part of a ship’s stern. Coxsivain, the person who steers a hoat, and has charge of her. Crab, a wooden apparatus, something like a capstan, but not furnished with a drum-head; it is used for similar purposes, with holes made to insert the bars. Crab, a machine with three claws, used to launch ships, to heave them into the dock, or off the quay. Cradle, a frame placed under the bot¬ tom of a ship, in order to conduct her steadily into the water when she is to be launched, at which time it supports her .weight while she slides down the descent or sloping passage, called the Ways, which are for this purpose daubed with soap or tallow. Craft, a general name for all sorts of vessels employed to load or dis¬ charge merchant ships, or to carry alongside or return the guns, stores, or provisions of a man-of-war: such are lighters, hoys, barges, etc. Cramp, a short bar of iron, with its ends bent so as to form three sides of a parallelogram: at one end a set-screw is inserted, so that two pieces of metal, being placed be¬ tween, can be held firmly together by the screw. Crane, a machine used for hoisting and lifting stones, ponderous weights, and heavy goods, principally at wharfs and warehouses, now much employed for hoisting heavy build¬ ing materials; also as travelling cranes on framed scaffolding, for the assistance of masons, brick¬ layers, and other artisans in build¬ ing, saving the time and labour formerly so much prolonged in the execution of the work to be done. Cranes, pieces of iron or timber at a vessel’s sides, used to stow boats or spars upon. Crank, the condition of a vessel when she is inclined to lean over a good deal, and cannot bear much sail: this may be owing to her construc¬ tion, or to her stowage. Crank, the arms projecting from the main shaft of an engine, joined to¬ gether at the outer ends. Crank, in mechanics, a square piece projecting from a spindle, serving by its rotation to raise and fall the pistons of engines: it also denotes the iron support for a lantern, and the iron made fast to the stock of a bell. Crank, in machinery, is a bend in an axle, by which a reciprocating mo¬ tion in a rod is made to produce a revolving motion of an axle and of a wheel which may be connected with it. Crank, in turning that part of the axle of the fly which is bent into three knees, or right angles, and three projecting parts : one of the parts is parallel to the axis, and has the upper part of the crank- hook collared round it. Crank-axle, the driving axle con¬ nected to the piston-rods of a loco¬ motive engine. Crank-hook, in turning, sometimes also called the connecting-rod, as it connects the treadle and the fly. Crank-pin, the cylindrical piece join¬ ing the ends of the crank arms, and attached to the connecting- rod, or, in vibrating engines, to the piston-rod: if the crank has only one arm, the pin projects from the end of it. Crayon, a chalk; a species of mate¬ rial for drawing. Black chalk, found in Italy, white chalk, found in France, and red chalk, form three of the best varieties of cra¬ yons : each has its own peculiar value as a drawing material. Creazes, in mining, the work or tin in the middle part of the buddle or dressing. Credence, the small table at the side of the altar, or communion table, on which the bread and wine were formerly placed before they were consecrated. Creeper, an iron instrument like a grapnel, with four claws, used for dragging the bottom of a harbour or river, to find anything lost. 131 CRE CROSS. CRO Cremona school of painting. Boc¬ caccio Boccaccino bears the same character among the Cremonese, as Ghirlandajo, Mantegna, Vanucci, etc., in their respective schools. Camillo Boccaccino was the chief master of this school, grounded in the ancient maxims of his father. Crenelle, the embrasure of a battle- i ment, or loopholes. Crepido, according to Pliny, any raised basement upon which other things are built or supported, as of a temple, altar, obelisk, etc. Crescent, or half-moon. ] Cresset, a candlestick or lamp to j contain a light. Crest, a term in heraldry ; the orna¬ ment of the helmet. ! Creste, the ornamented finishing sur¬ rounding a screen or canopy of a building. Crest-tiles, those used to cover the ridge of a roof, upon which they fit on the principle of a saddle. Creux, a kind of sculpture, when the lines and figures are cut and formed within the face of the plate. Cringle, a short piece of rope with each end spliced into the bolt-rope of a sail, confining an iron ring or thimble. Criplings, short spars at the sides of houses. Crista, a crest; the apex or highest part of a shrine. Crockets, ornaments of foliage or animals running up the back of a pediment, arch-pinnacle, or spire, from the corbels below to the finial above, in which latter the crockets on both sides appear to merge. Projecting leaves, flowers, or bunches of foliage, used in Gothic architecture to decorate the angles of spires, canopies, pinna¬ cles, etc. Cromlech, in British antiquity, high, broad, and fiat stones, raised upon other stones set on end, apparently for the purpose of an altar. Crop, ore or tin of the first quality, after it is dressed or cleaned for smelting. Crosette, a truss, or console, in the flank or return of an architrave of a door, window, or other aperture in a wall. Crosettes, in decoration, the trusses or consoles on the flanks of the architrave, under the cornice. Cross-beam, a beam laid across an¬ other. In a ship, a great piece of timber so called, crossing two others, called bites, and to which the cable is fastened, when a ship rides at anchor. Cross-jack, in a ship, is a small yard flung at the upper end of the mizen-mast under the top. Cross, a gibbet constructed of two pieces of wood placed transversely, whether they cross each other at right angles at the top, like a T, or in the middle of their length, like an X. Cross, the symbol of the Christian religion. Cross, cross crusse, cross-bar, cross goffan, cross lode, either a vein of a metallic nature, or a soft earth, clay, or flookan, like a vein, which unheads and intersects the true lode. Cross-bars, round bars of iron bent at each end, used as levers to turn the shank of an anchor. Cross-chocks, pieces of timber fayed across the deadwood amidships, to make good the deficiency of the heels of the lower futtocks. Cross {church), or a Greek cross, that in which the length of the trans¬ verse part is equal to that of the nave; so called because most of the Greek churehes were built in that form. Cross {church), or a Latin cross, that whose nave is longer than the cross part, as in most Gothic churches. Cross-grained stuff, in joinery, wood having its fibres running in con¬ trary positions to the surfaces, and which consequently cannot be made perfectly smooth when planed in one direction, without turning it or turning the plane. Cross-heads, in locomotive engines, 132 CRYPT. CRO the part of the motion into which the piston-rod is fitted on the cy¬ linder side and the connecting-rod attached on the driving wheel axle side. Cross-head guides, in locomotive en¬ gines, the parallel bars between which the cross-head moves in a right line with the cylinder and driving wheel axle: they are also called motion bars. Cross-head blocks, in locomotive en¬ gines,the parts which slide between the parallel guides. The ends of the cross-head are fitted into these blocks. The cross-head,, cross¬ head guides, and block, constitute what is called ‘ the motion of the engine.’ Cross-head, in the steam-engine, a cross-bar fixed centrally on the top of a piston-rod, and connected to the beam: its motion is confined to a direct line by guides at each end; or, in the side-lever and beam engines, by an apparatus called a * parallel motion.’ Cross-jack: the cross-jack yard is the lower yard on the mizen-mast. | Cross-spales, pieces of timber placed across a vessel, and nailed to the frames, to keep the sides together until the knees are bolted. Cross-somer, a beam of timber. ' Cross-springer, in groined vaulting, the rib which extends diagonally from one pier to another. Cross-trees, pieces of oak supported by the cheeks and trestle-trees at the mast-heads, to sustain the tops on the lower mast, and to spread the top-gallant rigging at the top¬ mast head. j Cross vaulting is formed by the inter¬ section of two or more simple vaults of arch-work. Crotchet, a support?, or piece of wood fitted into another to sustain it. Also crooked pieees of iron, used on board sloops and long-boats. Croud, or Crowde, a crypt, or under¬ croft of a church. | Crow, in mechanics, an iron lever, made with a sharp point at one CRY end, and two claws at the other; used in heaving and purchasing great weights. Crow-foot, a number of small lines rove through to suspend an awning. Croivn, in geometry, a plane ring in¬ cluded between two concentric perimeters, generated by the mo¬ tion of part of a right line round the centre, to which the moving part is not contiguous. Crown of an anchor, the place where the arms are joined tp the shank. Crown of an arch, that line or point upon its surface which is the highest or most elevated from its springing. Crown-post, the middle post of a trussed roof. Crown-wheels. Circular motion is communicated at right angles by means of teeth or cogs situated parallel to the axis of the wheel. Wheels thus formed are denomi¬ nated ‘crown’ or ‘contrate wheels: ’ they act either upon a common pinion or upon a lantern. Crazier, the pastoral staff of a bishop or mitred abbot, having the head curled round somewhat in the manner of a shepherd’s crook. Crucifix, a representation of our blessed Saviour on the cross. Crustce, figures or images in low relief, embossed upon plate. Crustarius, an artist; an engraver for inlaid work, etc. Crutch, a knee or piece of knee timber, placed inside a vessel to secure the heels of the cant-tim¬ bers abaft. Cryophorus, an instrument by which the freezing qualities of the atmo¬ sphere may be ascertained. Crypt, a vault beneath a building, either entirely or partly under¬ ground, frequently under churches and cathedrals. Crypta, or Crypt, among the Romans, any long narrow vault, whether wholly or partially below the level of the earth. Crypto Portico, an enclosed gallery or portico having a wall with 133 CUPBOARDS. CTE CUP openings or windows in it, instead of columns at the side. Ctesibica macliina, a double-actioned forcing-pump invented byCtesibius of Alexandria. Cuare (Cornish), a quarry of stones. Cubature, the cubing of a solid, or measuring of the space compre¬ hended in a solid, as in a cone, pyramid, cylinder, etc. Cube, in geometry, a regular or solid body consisting of six square and six equal faces and sides, and its angles all right and therefore equal. Cube, or Hexahedron, a solid regular body, consisting of six equal square sides. Cubes, or Cube numbers in arithmetic, and the theory of numbers, are those whose cube-root is a com¬ plete integer; or they are numbers produced by multiplying a given number twice into itself, or by the multiplication of three equal fac¬ tors. Cube-root, of a number, say 8, the number which multiplied into itself twice will produce 8,—namely, 2 ; or it is that number by which, if you divide a number twice, the quotient will be equal to itself. Cubic foot of water, what a vessel one foot square and one foot deep will hold. Cubicule, among the Romans, a bed¬ chamber, tent, or balcony. Cubiculum, according to Pliny, a room furnished with a sofa or bed. Cubile, the ground-work or lowest course of stones in a building. Cubit, a measure used among the ancients, and which the Hebrews call ‘ amma,’ the mother of other measures. A cubit was originally the distance from the elbow to the extremity of the middle finger; which is the fourth part of a well- proportioned man’s stature. Cubital, a bolster or cushion for the elbow to rest upon, for invalids. Cuboch, a name for the unit or in¬ teger of a power, being the effect produced by one cubic foot of water in one foot perpendicular descent. Cuckold's-neck, a knot by which a rope is secured to a spar, the two parts of the rope crossing each other and seized together. Cuddy, a cabin in the fore part of a boat. Culage, the laying up a ship in the dock, to be repaired. Cul-de-four of a niche, arched roof of a niche, on a circular plan, a sphe¬ rical vault. Cul-de-lampe, for several decorations both of masonry and ironery. Cullis, a gutter in a roof; any groove or channel. Culm, stone coal, resembling the Kil¬ kenny coal of Ireland. Culmen, the roof of a house or church. Culverhouse, a dove-cot or pigeon- house. Culvert, an arched drain for the pas¬ sage of water. Culvert, an arched passage or bridge beneath a road, canal, or railway. Culver-tail, to dove-tail. Cuneus, the wedge. Cuneus, the division of the audience part of a theatre comprehended between two adjoining scalaria or staircases which lead from one praecinctio to another: so called from its form, which resembles a wedge. The foremost cunei were termed ‘ cavea prima;’ the middle, ‘ cavea mediaand the uppermost, ‘ cavea summa.’ The whole of the audience part, exclusive of the or¬ chestra, was likewise called ‘cavea.’ Cupboards answered in some respects to the sideboards of the present day. They were sometimes mere planched tops, resting on trestles, or fixed with legs against the wall ; at others, framed on stages, rising one above another, and moveable : these w T ere called ‘ joined cupboards,’ occasionally carved, and, like tables, covered with carpets. At the marriage of Prince Arthur, son of Henrv VII., in the hall was a triangular cup- 134 CUP CYCLOIDAL CURVES. CYC board, five stages high, set with plate, valued at £1200, entirely ornamental ; and in the “ utter chamber,” where the princess dined, was another cupboard, “ set with gold plate, garnished with stone and pearl,” and valued at £20,000. Cupola, a small room, either circular or polygonal, standing on the top of a dome : by some it is called a lantern. Cupola, a spherical or spheroidal covering to a building, or any part of it. Cup-valve, for a steam-engine: it re¬ sembles a conical valve, made to fit a cover in the form of a vase or of the portion of a sphere. Curia, in architecture; the building in which the highest council of the Roman state assembled, described by Vitruvius as being adjacent to the agora or forum. Curling-stuff, in joinery, that which is produced by the winding or coiling of the fibres round the boughs of a tree, when they begin to shoot out of the trunk. Current, a stream or flux of water in any direction. The setting of the current is that point of the com¬ pass towards which the waters run ; and the drift of a current is the rate it runs per hour. Curtilage, a term formerly applied to the division or boundary of mano¬ rial lands. Curve, in geometry, a line wherein the several points of which it con¬ sists tend several ways, or are po¬ sited towards different quarters. Curvilinear, consisting of curved lines. Cushion-capital, the capital of a co¬ lumn so sculptured as to resemble a cushion pressed down by the weight of its entablature. Cushions and window-pillows were, in Tudor times, stuffed—not unlike the woolsack of the Lord Chancel¬ lor—in round, square, and oblong shapes, covered with carpet-work, velvet, or embroidery ; the family arms frequently supplying the de¬ vice. Cusp, an ornament generally in Gothic windows or doors ; it is to be found in the concave bends of stone-work. Cusps, projecting points forming the featherings or foliation in Gothic tracery, archery, panels, etc. Cut, in mining, to intersect a vein, branch, or lode, by driving hori¬ zontally or sinking perpendicularly at right angles. Cutter, a small boat; also a kind of sloop. Cutting. Cutting instruments act in dividing bodies upon the same principle as the wedge. The blade of the instrument is in general a thin wedge, but the edge itself is usually much more obtuse. Cutwater, in a ship, is the sharp part of the head under the beak or figure. Cycle, a round of time; a space in which the same revolution begins again ; a periodical space of time. A lunar cycle is a period of nine¬ teen years. A solar cycle is a period of twenty-eight years, after which the days of the mouth re¬ turn to the same days of the week. Cyclograph, or Arcograph, an instru¬ ment for drawing arcs of circles without centres, used in architec¬ tural and engineering drawings when the centres are too distant to be conveniently accessible. Cycloidal curves are defined as fol¬ lows : 1. When a circle is made to rotate on a rectilinear basis, the figure described on the plane of the basis by any point in the plane of the circle is called a trochoid : a circle concentric with the gene¬ rating circle, and passing through the describing circle. 2. If the describing point is in the circum¬ ference of the rotating circle, the two circles coincide, and the curve is called a cycloid. 3. If a circular basis be substituted for a rectilinear one, the trochoid will become an epitrochoid, and the cycloid an epicycloid. 135 CYPRESS-TREE. CYC Cyclopean Architecture, a class of building supposed to have preceded the invention of the classic orders in Greece, and attributed to the Cyclopes. Cyclopean wall, the oldest example of mason-work in Italy: in town-walls only has this style of building been used. The history of its origin is obscure. A large irregular mass of stone, having three, four, five, or more sides, hewn only on the irregular sides to be built upon, begins a wall: to this mass others are added, the sides of which are made to fit the irregular sides of the first block ; and on these again others of similar forms are built in the same manner. Cyclostylar, relating to a structure composed of a circular range of columns without a core; with a core, the range would be a peri¬ style. Cylinder, a body having two flat sur¬ faces and one circular : for in¬ stance, a roller is a cylinder. Cylinder, a roller used for levelling and condensating the ground in agricultural and other operations. Cylinders, in steam-engines, hollow cylindrical vessels : within the cy¬ linder the steam exerts its power upon the piston, which, by means of its rod, transmits it to the other parts of the engine. In locomotive engines, hollow vessels, usually made of cast-iron, and bored out accurately, into which pistons are fitted steam-tight, yet easily mov¬ able by the pressure of the steam. Cylinder cocks, in steam-engines, cocks placed in convenient parts of the cylinder for admitting oil to lubricate the piston, or by which to blow out the condensed steam, or any deposit in the cylinders. Cylinder cover, in steam-engines, the lid bolted to a flanch round the top of a cylinder, so as to be perfectly CYZ steam-tight: it has a stuffing-box cast in the centre, through which the piston-rod alternates. Cylindrical vault, a vault without groins, resting upon two parallel walls. Cylindrical walling is that erected upon a circular plan, forming a cylinder, or a part less than a cy¬ linder, according as the plan is an entire circumference or a less por¬ tion. Cyling, anciently ceiling. Cyma, called also cymatium, its name arising from its resemblance to a wave ; a moulding which is hollow in its upper part, and swelling be¬ low. There are two sorts,—the Cyma recta, just described, and the Cyma reversa, whose upper part sw 7 ells, whilst the lower part is hollow. Cymatium, a moulding w hose section or profile is convex below and con¬ cave above, somewhat resembling the letter S. Cymatium, in sculpture, carved work, resembling rolling waves. Cymophane, a mineral of a green colour, resembling the clirysobervl. Cypress-tree, one of the evergreens ; very proper to mix with pines and firs in forming clumps. The wood of the cypress is very valuable, W'hen grown to a size fit for planks, which dimension it attains in as short a time as oak. It was much used by the ancients, and was em¬ ployed in the original doors of St. Peter’s at Rome, which, on being replaced, after six hundred years, by gates of brass, were found to be perfectly free from decay, and wdth- in to have retained part of the ori¬ ginal odour of the wood. Cyrtostyle, a circular projecting por- -tico. Cyzicenus, anciently a hall decorated with sculpture. 136 DAC DAGUERREOTYPE. DAT D. Dactylus, a Greek measure of length, the sixteenth part of an English foot. Dado, a term for the die or plane face of a pedestal. The dado em¬ ployed in the interior of buildings is a continuous pedestal, with a plinth and base moulding, and a cornice or dado moulding sur¬ mounting the die. Dado, the solid block or cube forming the body of a pedestal, in classical architecture, between the base mouldings and cornice; an archi¬ tectural arrangement of mouldings, etc., round the lower part of the walls of a room. Dagger, in ship-building, a piece of timber that crosses all the poppets of the bulge-ways, to keep them together: the plank that secures the heads of the poppets is called the dagger-plank. Dagger knees are lodging knees, with side arms cast down and bolted through the clamp : they are placed at the lower decks of some ships, instead of hanging knees, to pre¬ serve as much stowage in the hold as possible. Daguerreotype, sun drawing ; na¬ ture’s drawing by the aid of light. It was the invention of two French¬ men, M. Daguerre and M. Niepce. The invention consists of the fix¬ ation of the images formed on the focus of the caiuera-obscura; is made on very smooth surfaces of pure silver plated on copper. Dairy-house, a place for keeping milk. Dais, in early domestic architecture, the chief seat at the high board or principal table (cross-table) in a baronial hall; also the principal table itself, and the raised part of the floor on which it is placed. •Dais, a canopy to cover an altar, throne, or tribunal; the chief or upper table in a monastery. Dam, a bank or obstruction built across a river or stream, for the purpose of raising the level of the water on the opposite side of it. Dams built for the purpose of in¬ land navigation, or for that of se¬ curing a water power, may be con¬ sidered as having a more permanent character. Damascus steel, a sort of steel brought from the Levant, greatly esteemed for the manufacture of cutting in¬ struments. Damasquine, a term applied to orna¬ mental work of gold or silver, in- crusted on iron or steel. Darnonico or Monicon, an iron ochre, being a compound of terra di sienna and Roman ochre, burnt, and hav¬ ing all their qualities : it is rather more russet in hue than the orange de Mars, has considerable transpa¬ rency, is rich and durable in colour, and affords good flesh tints. Damper, a valve placed in a chimney, to diminish the draught when the heat is too intense. Damper, in locomotive engines, a kind of iron Venetian blind, fixed to the smoke-box end of the boiler, in front of the tubes : it is shut down when the engine is standing, and thus stops the draught and econo¬ mizes fuel; but it is opened when the engine is running. Damps: various kinds of permanently elastic fluids generated in mines are thus named by the miners : choke-damps consist mostly of carbonic acid gas, and fire-damps of carburetted hydrogen gas. Dancette, in heraldry, zigzag or chevron fret; seen in Norman buildings. Dark ages were periods when the monks and ecclesiastics were the only learned persons : when reli¬ gion, law, politics, and physics were administered and controlled by the clergy, denominated clerks. Data useful in various calculations of the properties of materials. [The data correspond to the mean tern- 137 DAT DATA. DAT perature and pressure of the atmo¬ sphere ; the materials are assumed to he dry, and the temperature is measured by Fahrenheit’s scale.] Air. Specific gravity, 0'0012; weight of a cubic foot, 0 - 07531bs., or 527 grains (Shuckburgh); 13'3 cubic feet, or 17 cylindric feet of air, weigh 1 lb.; it expands or •00208 of its bulk at 32° by the addition of one degree of heat. (Dulong and Petit.) Ash. Specific gravity, 0'76; weight of a cubic foot, 47‘5 lbs.; weight of a bar 1 foot long and 1 inch square, 0'33 lbs.; will bear without permanent alteration a strain of 3540 lbs. upon a square inch, and an extension of of its length ; weight of modulus of elas¬ ticity for a base of an inch square, 1,640,000 lbs.; height of modulus of elasticity, 4,970,000 feet; mo¬ dulus of resilience, 7’6; specific resilience, 10. (Calculated from Barlow’s experiments.) Compared with cast iron as unity, its strength is 0’23 ; its extensibi¬ lity, 2'6 ; and its stiffness, 0’089. Atmosphere. Mean pressure of, at London, 28 - 89 inches of mercury = 14T81bs. upon a square inch. (Royal Society.) The pressure of the atmosphere is usually estimated at 30 inches of mercury, which is very nearly 13| lbs. upon a square inch, and equivalent to a column of water 34 feet high. Beech. Specific gravity, 0 696; weight of a cubic foot, 45 - 3 lbs.; weight of a bar 1 foot long and 1 inch square, 0 - 3151b.; will bear without permanent alteration on a square inch, 2360 lbs., and an ex¬ tension of -gJ-o of its length ; weight of modulus of elasticity for a base of an inch square, 1,345,000 lbs.; height of modulus of elasticity, 4,600,000 feet; modulus of resi¬ lience, 4'14 ; specific resilience, 6 . (Calculated from Barlow’s Experi¬ ments.) Compared with cast iron as unity, its strength is 0*15; its extensi¬ bility, 2'1 ; and its stiffness, 0 073. Brass, cast. Specific gravity, 8.37; weight of a cubic foot, 523 lbs.; weight of a bar 1 foot long and 1 inch square, 3’63 lbs.; ex¬ pands of its length by one degree of heat (Troughton) ; melts at 1869° (Daniell); cohesive force of a square inch, 18,000 lbs. (Ren¬ nie) ; will bear on a square inch without permanent alteration, 6700 lbs., and an extension in length of ; weight of modulus of elasticity for a base of an inch square, 8,930,000 lbs.; height of modulus of elasticity, 2,406,000 feet; modulus of resilience, 5; specific resilience, 0 6 . (Tredgold). Compared with cast iron as unity, its strength is 0'435; its extensi¬ bility, 0 - 9 ; and its stiffness, 0'49. Brick. Specific gravity, 1841 ; weight of a cubic foot, 115 lbs.; absorbs of its weight of water ; cohesive force of a square inch, 275 lbs. (Tredgold) ; is crushed by a force of 562 lbs. on a square inch (Rennie.) Brick-work. Weight of a cubic foot of newly built, 117 lbs.; weight of a rod of new brick-work, 16 tons. Bridges. When a bridge is covered with people, it is about equivalent to a load of 120 lbs. on a superficial foot; and this may be esteemed the greatest possible ex¬ traneous load that can be collected on a bridge; while one incapable of supporting this load cannot be deemed safe. Bronze. See Gun-metal. Cast Iron. Specific gravity, 7'207 ; weight of a cubic foot, 450 lbs.; a bar 1 foot long and 1 inch square weighs 3 - 21bs. nearly; it expands of its length by one degree of heat (Roy); greatest change of length in the shade in this climate, xy-V 3 ; greatest change ; of length when exposed to sun’s rays, xsVtrl melts at 3479° (Da¬ niell), and shrinks in cooling from T>V to ws ' ts length (Muschet); 138 DAT DATA. DAT is crushed by a force of 93,000 lbs. upon a square inch (Rennie); will bear -without permanent alteration 15,300 lbs. upon a square inch, and an extension of of its length; weight of modulus of elasticity, for abase 1 inch square,18,400,OOOlbs.; height of modulus of elasticity, 5,750,000 feet; modulus of resi¬ lience, 12'7; specific resilience, 1‘7G. (Tredgold.) Chalk. Specific gravity, 2-315 ; weight of a cubic foot, 144'7 lbs.; is crushed by a force of 500 lbs. on a square inch. (Rennie.) Clay. Specific gravity, 2 - 0; weight of a cubic foot, 125 lbs. Coal, Newcastle. Specific gra¬ vity, 1-269 ; weight of a cubic foot, 79 31 lbs. A London chaldron of 36 bushels weighs about 28 cwt., whence a bushel is 87 lbs. (but is usually rated at 84 lbs.) A New¬ castle chaldron, 53 cwt. (Smea- ton.) Copper. Specific gravity, 8-75 (Hatchett); weight of a cubic foot, 549 lbs.; weight of a bar 1 foot long and 1 inch square, 3 81 lbs.; expands in length by one degree of heat, Y 0 /900 (Srueaton); melts at 2548° (Daniell ); cohesive force of a square inch, when hammered, 33,000 lbs. (Rennie.) Earth, common. Specific gra¬ vity, 1 -52 to 2-00; weight of a cubic foot, from 95 to 125 lbs. Elm. Specific gravity, 0-544 ; weight of a cubic foot, 34 lbs.; weight of a bar 1 foot long and 1 inch square, 0 236 lbs.; will bear on a square inch without permanent alteration, 3240 lbs., and an ex¬ tension in length of ; weight of modulus of elasticity for a base of an inch square, 1,340,000 lbs.; height of modulus of elasticity, 5,680,000 feet; modulus of resi¬ lience, 7 - 87; specific resilience, 14-4. (Calculated from Barlow’s Experiments.) Compared with cast iron as unity, its strength is 0-21 ; its extensi¬ bility, 2 9 ; and its stiffness, 0'073. Fir, red or yellow. Specific gra¬ vity, 0-557 ; weight of a cubic foot, 34 8 lbs.; weight of a bar 1 foot long and 1 inch square, 0-242 lb.; will bear on a square inch without permanent alteration, 4290 lbs. = 2 tons nearly, and an extension in length of yto! weight of modulus of elasticity for a base of an inch square, 2,016,000 lbs.; height of modulus of elasticity, 8,330,000 feet; modulus of resilience, 9"13 ; its specific resilience, 16 - 4. (Tred¬ gold.) Compared with cast iron as unity, its strength is 0 - 3 ; its extensibility, 2-6, and its stiffness, 0-1154,= s-S-e- Fir, white. Specific gravity, 0-47; weight of a cubic foot, 29-3 lbs.; weight of a bar 1 foot long and 1 inch square, 0-204 lb. ; will bear on a square inch without perma¬ nent alteration, 3630 lbs., and an extension in length of ; weight of modulus of elasticity for a base of an inch square, 1,830,000 lbs. ; height of modulus of elasticity, 8,970,000 feet; modulus of resi¬ lience, 7 - 2 ; specific resilience, 15-3. (Tredgold.) Compared with cast iron as unity, its strength is 0-23'; its extensibi¬ lity, 2-4 ; and its stiffness, 0-1. Floors. The weight of a super¬ ficial foot of a floor is about 40 lbs. when there is a. ceiling, counter¬ floor, and iron girders. When a floor is covered with people, the load upon a superficial foot may be calculated at 120 lbs,: therefore, 120 + 40 = 160 lbs. on a superficial foot is the least stress that ought to be taken in estimating the strength for the parts of a floor of a room. Force. See Gravity, Horse, etc. Granite, Aberdeen. Specific gravity, 2-625 ; weight of a cubic foot, 164 lbs.; is crushed by a force of 10 910 lbs. upon a square inch. (Rennie.) Gravel. Weight of a cubic foot, about 120 lbs. Gravity generates a velocity 139 DAT DATA. DAT of 32£ feet in a second in a body falling from rest; space described in the first second, 16^ feet. Gun-metal, cast (copper 8 parts, tin 1). Specific gravity, 8153; weight of a cubic foot, 509 F lbs.; weight of a bar 1 foot long and 1 inch square, 3'54 lbs. (Tredgold) ; expands in length by 1° of heat, c- g7r (Smeaton); will bear on a square inch without per¬ manent alteration, 10,000 lbs., and an extension in length of ; weight of modulus of elasticity for a base 1 inch square, 9,873,000 lbs.; height of modulus of elasticity, 2,790,000 feet; modulus of resi¬ lience, and specific resilience, not determined. (Tredgold.) Compared with cast iron as unity, its strength is 0-65; its extensibi¬ lity, 1*25 ; and its stiffness, 0-535. Horse, of average power, pro¬ duces the greatest effect in draw¬ ing a load when exerting a force ofl87 F lbs. with a velocity of 2i feet per second, working 8 hours in a day. (Tredgold.) A good horse can exert a force of 480 lbs. for a short time. (Desaguliers.) In calculating the strength for horse machinery, the horse’s power should be considered 400 lbs. Iron, cast. See Cast Iron. Iron, malleable. Specific gravity, 7'6 (Muschenbroek); weight of a cubic foot, 475 lbs.; weight of a bar 1 foot long and 1 inch square, 3 - 3 lbs. ; ditto, when hammered, 3 - 4 lbs.; expands in length by 1° of heat, ^Voo (Smeaton); good English iron will bear on a square inch without permanent alteration, 17,800 lbs. = 8 tons nearly, and an extension in length of 1 / 00 ; cohe¬ sive force diminished b. v an elevation l°of temperature; weight of modulus of elasticity for a base of an inch square, 24,920,000 lbs.; height of modulus of elasticity, 7,550,000 feet; modulus of resi¬ lience, and specific resilience, not determined. (Tredgold.) Compared with cast iron as unity, its strength is 1 • 12 ; its extensibi¬ lity, 0'86 ; and its stiffness, 1*3. Larch. Specific gravity, -560 ; weight of a cubic foot, 35 lbs.; weight of a bar 1 foot long and 1 inch square, 0-243 lb.; will bear on a square inch without perma¬ nent alteration, 2065 lbs., and an extension in length of ; weight of modulus of elasticity for a base of an inch square, 10,074,000 lbs.; height of modulus of elasticity, 4,415,000 feet; modulus of resi¬ lience, 4; specific resilience, 7'1. (Calculated from Barlow’s Experi¬ ments.) Compared with cast iron as unity, its strength is 0-136; its extensi¬ bility, 2'3 ; and its stiffness, 0-058. Lead, cast. Specific gravity, 11-353 (Brisson); weight of a cubic foot, 709'5 lbs.; weight of a bar 1 foot long and 1 inch square, 4-94 lbs.; expands in length by 1 degree of heat, Fg * 00 (Smeaton); melts at 612° (Crichton); will bear on a square inch without per¬ manent alteration, 1500 lbs., and an extension in length of FFF ; weight of modulus of elasticity for a base 1 inch square, 720,000 lbs.; height of modulus of elasticity, 146,000 feet; modulus of resi¬ lience, 3-12; specific resilience, 0-27 (Tredgold). Compared with cast iron as unity, its strength is 0-096; extensi¬ bility, 2 5; and its stiffness, 0'0385. Mahogany, Honduras. Specific gravity, 0'56 ; weight of a cubic foot, 35 lbs. ; weight of a bar 1 foot long and 1 inch square, 0'2431b.; will bear on a square inch without permanent alteration, 3800 lbs., and an extension in length of ; weight of modulus of elasicity for a base 1 inch square, 1,596,000 lbs.; height of modulus of elasticity, 6,570,000 feet; modulus of resi¬ lience, 9-047 ; specific resilience, 16* 1. (Tredgold.) Compared with cast iron as unity, its strength is 0'24 ; its extensibi¬ lity, 2'9 ; and its stiffness, 0-487. 140 DATA. DAT Man. A man of average power produces the greatest effect when exerting a force of 31J lbs. with a velocity of 2 feet per second, for 10 hours in a day. (Tredgold.) A strong man will raise and carry from 250 to 300 lbs. (Desaguliers.) Marble, white. Specific gra¬ vity, 2-706; weight of a cubic foot, 169 lbs; weight of a bar 1 foot long and 1 inch square, 1-17 lb. ; cohesive force of a square inch, 1811 lbs.; extensibility, of its length ; weight of modulus of elas¬ ticity for a base of an inch square, 2,520,000 lbs.; height of modulus of elasticity, 2,150,000 feet; mo¬ dulus of resilience at the point of fracture, l - 3 ; specific resilience at the point of fracture, 0'48 (Tred¬ gold) ; is crushed by a force of 6060 lbs. upon a square inch (Rennie). Mercury. Specific gravity, 13'568 (Brisson); weight of a cubic inch, 0-4948 lb.; expands in bulk by 1° of heat, (Dulong and Petit) ; weight of modulus of elasticity for a base of an inch square, 4,417,000 lbs.; height of modulus of elasticity, 750,000 feet. (Dr. Young, from Canton’s Experi¬ ments.) Oak, good English. Specific gravity, 0'83; weight of a cubic foot, 52 lbs.; weight of a bar 1 foot long and 1 inch square, 0-36 lb.; will bear upon a square inch with¬ out permanent alteration, 3960 lbs., and an extension in length of T i Ty ; weight of modulus of elasticity for abase 1 inch square, 1,700,000 lbs.; height of modulus of elasticity, 4,730,000 feet; modulus of resi¬ lience, 9-2; specific resilience, 11. (Tredgold.) Com pared with cast iron as unity, its strength is 0-25 ; its extensibi- ( lity, 2'8 ; and its stiffness, 0 093. Pendulum. Length of pendu¬ lum to vibrate seconds in the lati¬ tude of London, 39-1372 inches (Rater); ditto to vibrate half- seconds, 9‘7843 inches. DAT Pine, American yelloio. Specific gravity, 0'46 ; weight of a cubic foot, 26f lbs.; weight of a bar 1 foot long and one inch square, 0-1861b. ; will bear on a square inch without permanent alteration, 3900 lbs.,and an extension in length of-rnr! we ight of modulus of elas¬ ticity for a base of an inch square, 1,600,000 lbs.; height of modulus of elasticity, 8,700,000 feet; mo¬ dulus of resilience, 9-4; specific resilience, 20. (Tredgold.) Compared with cast iron as unity, its strength is 0'25 ; its ex¬ tensibility, 2'9 ; and its stiffness, 0-087. Porphyry, red. Specific gra¬ vity, 2-871 ; weight of a cubic foot, 179 lbs.; is crushed by a force of 35,568 lbs. upon a square inch. (Gauthey.) Rope, hempen. Weight of a common rope 1 foot long and 1 inch in circumference, from 0-04 to 0-46 lb.; and a rope of this size should not be exposed to a strain greater than 200 lbs.; but in com¬ pounded ropes, such as cables, the greatest strain should exceed 120 lbs.; and the weight of a ca¬ ble 1 foot in length and 1 inch in circumference does not exceed 0-027 lb. The square of the circum¬ ference in inches multiplied by 200 will give the number of pounds a rope may be loaded with; and multiply by 120 instead of 200 for cables. Common ropes will bear a greater load with safety after they have been some time in use, in con¬ sequence of the tension of the fibres becoming equalized by repeated stretfchings and partial untwisting. It has been imagined that the im¬ proved strength was gained by their being laid up in store ; but if they can there be preserved from deterioration, it is as much as can be expected. Roofs. Weight of a square foot of Welsh rag slating, 11 Jibs.; weight of a square foot of plain tiling, 16Jlbs.; greatest force of the wind 141 DAT DATA. DAT upon a superficial foot of roofing may be estimated at 40 lbs. Slate, Welsh. Specific gavity, 2'752 (Kirwan); weight of a cubic foot, 172 lbs.; weight of a bar 1 foot long and 1 inch square, 1 • 19 lb.; cohesive force of a square inch, 11,500 lbs.; extension before frac¬ ture, -j-g- 7 -o ; weight of modulus of elasticityforabase of aninch square, 15,800,000 lbs.; height of modulus of elasticity, 13,240,000 feet; mo¬ dulus of resilience, 8-4 ; specific re¬ silience, 2 (Tredgold). Slate, Westmoreland. Cohe- siveforceof a square inch, 7870 lbs.; extension in length before fracture, tbVo > weight of modulus of elas¬ ticity for a base of an inch square, 12,900,000 lbs. (Tredgold.) Slate, Scotch. Cohesive force of a square inch, 9600 lbs.; exten¬ sion in length before fracture, ; weight of modulus of elasticity for a base 1 inch square, 15,790,000 lbs. (Tredgold.) Steam. Specific gravity at 212° is to that of air at the mean tem¬ perature as 0-472 is to 1 (Thomson); w eight of a cubic foot, 249 grains ; modulus of elasticity for a base of an inch square, 14f lbs.; when not in contact with w r ater, expands of its bulk by 1° of heat (Gay- Lussac). Steel. Specific gravity, 7‘84; weight of a cubic foot, 490 lbs.; a bar l foot long and 1 inch square weighs 3/4 lbs.; it expands in length by 1 ° of heat, ysyijuo (Roy); tem¬ pered steel will bear without per¬ manent alteration, 45,000 lbs.; co¬ hesive force of a square inch, 130,000 lbs. (Rennie); cohesive force diminished 3 -oVu by elevating the temperature 1 °; modulus of elasticity for a base of an inch square, 29,000,000 lbs.; height of modulus of elasticity, 8,530,000 feet. (Dr. Young.) Stone, Portland. Specific gra¬ vity, 2113; weight of a cubic foot, 132 lbs.; weight of a prism 1 inch square and 1 foot long, 0 921b.; absorbs T *y of its weight of water (R. Tredgold) ; is crushed by a force of 3729 lbs. upon a square inch (Rennie); cohesive force of a square inch, 857 lbs.; extends be¬ fore fracture yy§-g °f Rs length ; modulus of elasticity for a base of an inch square, 1,533,000 lbs. ; height of modulus of elasticity, 1,672,000 feet; modulus of resi¬ lience at the point of fracture, 0-5 ; specific resilience at the point of fracture, 0-23. (Tredgold.) Stone, Bath. Specific gravity, L975 ; weight of a cubic foot, 123-4 lbs.; absorbs Jy of its weight of water (R. Tredgold) ; cohesive force of a square inch, 478 lbs. (Tredgold.) Stone, Craigleith. Specific gra¬ vity, 2-362 ; weight of a cubic foot 147’6 lbs. absorbs y’y of its weight of water; cohesive force of a square inch, 772lbs. (Tredgold); is crushed by a force of 5490 lbs. upon a square inch (Rennie). Stone, Dundee. Specific gra¬ vity, 2-621; weight of a cubic foot, 163’8 lbs; absorbs yiy P art °f R s weight of water; cohesive force of a square inch, 2661 lbs. (Tredgold); is crushed by a force of 6630 lbs. upon a square inch (Rennie). Stone-work. Weight of a cubic foot of rubble--work, about 140 lbs.; of hewn stone, 160 lbs. Tin, cast. Specific gravity, 7-291 (Brisson); w r eight of a cubic foot, 455-7 lbs.; weight of a bar 1 foot long and 1 inch square, 3-165 lbs.; expands in length by 1 ° of heat, ttsto (Smeaton) ; melts at 442° (Crichton); will bear upon a square inch without permanent alteration, 2880 lbs., and an extension in length of yyyo > modulus of elas¬ ticity for a base of an inch square, 4,608,000; height of modulus of elasticity, 1,453,000 feet; modulus of resilience, 18; specific resili¬ ence, 0-247 (Tredgold). Compared with cast iron as unity, its strength is 0-182 ; its extensibi¬ lity, 0'75 ; and its stiffness, 0-25. 142 )AT DEAD COLOURING. DEA Water, river. Specific gravity, 1-000 ; weight of a cubic foot, 62-5 lbs.; weight of a cubic inch, 252-525 grains; weight of a prism 1 foot long and 1 inch square, 0-434 lb.; weight of an ale gallon of water, 10-2 lbs.; expands in bulk by 1° of heat, ^-g (Dalton); ex- pands in freezing, ^ of its bulk (Williams); and the expanding force of freezing water is about 35,000 lbs. upou a square inch, ac¬ cording to Muschenbroek’s valua¬ tion ; modulus of elasticity for a base of an inch square, 326,0001bs.; height of modulus of elasticity, 750,000 feet, or 22,100 atmo¬ spheres of 30 inches of mercury. (Dr. Young, from Canton’s Expe¬ riments.) Water has a state of maximum density at or near 40°, which is con¬ sidered an exception to the general law of expansion by heat: it is extremely improbable that there is anything more than an apparent exception, most likely arising from water at low temperatures absorb¬ ing a considerable quantity of air, which has the effect of expanding it, and consequently of causing the apparent anomaly. Water, sea. Specific gravity, D0271; weight of a cubic foot, 64-2 lbs. Water is 828 times the density of air of the temperature 60°, and barometer 30. Whale-bone. Specific gravity, 1 3 ; weight of a cubic foot, 81 lbs.; will bear a strain of 5600 lbs. upon a square inch without permanent alteration, and an extension in length of modulus of elas¬ ticity for a base of an inch square, 820,000 lbs.; height of modulus of elasticity, 1,458,000 feet; modulus of resilience, 38-3 ; specific resili¬ ence, 29. (Tredgold.) Wind. Greatest observed ve¬ locity, 159 feet per second (Ro- chon); force of wind with that ve¬ locity, about 57J lbs. on a square foot. Zinc cast. Specific gravity, 7-028 (Watson); weight of a cubic foot, 439^ lbs; weight of a bar 1 inch square and 1 foot long, 3 05 lbs.; expands in length by 1° of heat, giwo (Smeaton) ; melts at 648° (Daniell); will bear on a square inch without permanent al¬ teration, 5700 lbs. = 0-365 cast iron, and an extension in length of g-fgo = £ of cast iron (Tredgold); modulus of elasticity for a base of an inch square, 13,680,000 lbs.; height of modulus of elasti¬ city, 4,480,000 feet; modulus of resilience, 2 - 4 ; specific resilience, 0-34. (Tredgold.) Compared with cast iron as unity, its strength is 0"365 ; its extensi¬ bility, 0-5 ; and its stiffness, 0 - 76. Data , a term for such facts, things, or quantities as are given or known, in order thereby to find other things that are unknown. Davit , in navigation, a short boom fitted in the fore channel, to hoist the flukes of the anchor to the how, which is called ‘ fishing the anchor.’ David's-staff, an instrument used in navigation. Day , or Bay, in architecture, one of the lights or compartments between mullion and mullion, in the great windows of the pointed style. Days, in early domestic architecture, the bay or lights of a window ; the spaces between the mullions. Dead colouriny is the first layer of colours, consisting usually of some shade of grey. Its design is to receive and preserve the finishing colours; and it is called dead be¬ cause it is not seen when the work is completed. Dead doors, in ship-building, fitted to the outside of the quarter-gallery doors, in case the quarter-gallery should be carried away. Dead eyes, fixed in the channels, with three holes to receive the lanyard of the shrouds. Deadflat, the nameof a midship board Dead lights, in navigation, wooden 143 DECORATION. DEA DEC shutters for the cabin windows, which are fastened on when the sea runs high. Dead-men's-eyes (in a ship), small blocks or pulleys with many holes, but no shivers wherein run the laniers. Dead-neap, a low tide. Dead reckoning, the estimation which seamen make of the ship’s place, by keeping an account of her way by the log, by the course steered, and by rectifying the whole by al¬ lowance for drift, leeway, etc. Dead rising, is that part of the ship that lies aft, between her keel and floor timbers. Dead ropes, ropes which do not run in any block or pulley. Deads (among miners), the earth or other fossil substances which en¬ close the ore on every side. Dead shore, a piece of timber worked up in brick-work, to support a su¬ perincumbent mass until the brick¬ work w'hich is to carry it has set or become hard. Dead water, the eddy water imme¬ diately at the stern of a ship while under way. Dead wood, pieces of timber fayed on the keel to seat the flow-tim¬ bers on afore and abaft the floors, and continued as high as the cutting down of the floors. Deafening sound-hoarding, the pug¬ ging used to prevent the passage of sound through wooden partitions. Dearn, a door-post, or threshold; to conceal, or shut up. Deambulatory, an ambulatory or clois¬ ter for exercise ; also the aisles of a church, or the porticoes round the body of a church. Debacle, a great aqueous torrent, a breaking up and transport of mas¬ sive rocks and gravel by an enor¬ mous rush of water. Debris, fragments of rocks, boulders, gravel, sand, trunks of trees, etc., detached from the summits and sides of mountains by the effect of the elements. Decade, the sum of ten. Decagon, in geometry, a plain figure of ten sides. Decalogue, the Ten Commandments delivered to the Israelites from Mount Sinai, in which the moral law is summarily comprehended. I The Jews call these precepts ‘ The | Ten Words.’* In the building of ! new churches, and in the restore- j tion of those of olden times, a pro¬ per and effective style of painting and embellishing the words of the ten commandments in face of the altar has been introduced. Decanicum, an ecclesiastical prison. Decastyle, in architecture : a temple is said to be decastyle when its por¬ tico contains ten columns in aline. Decastyle, a portico consisting of ten columns in front. Decempeda, a ten-foot rod employed by architects and surveyors for taking measurements. Decemremis, a vessel with ten banks of oars on a side. Decimal, the tenth part. Deck, the floor of a ship. Decoration, the combination of orna¬ mental objects which are employed in great variety, principally for the interior and exterior of all kinds of edifices, and for purposes of art generally. Decoration, when judi¬ ciously introduced, becomes in many instances a language, intel- j ligible only, however, when the artist is capable of speaking it correctly and the spectator of comprehending it. It is then a system of hieroglyphic writing, and the building to which it is ap¬ plied becomes historical, and tells its tale more nobly and appro¬ priately than it can ever do through the undignified medium of mural inscriptions. Nothing can be more judicious or appropriate than the sculpture in the metopes and pedi-! * To these the Saviour added another : “ A new commandment I give unto you. That ye love one another; as I have loved you, that ye also love one another.” (John xiii. 34.) 144 DEC DEFINITIONS IN GEOMETRY. DEF merit of the Parthenon. Ornament here not only creates a variety on the surface of the work, but re¬ lates, by the aid of the sculptor, a history intimately connected with the religious and moral destination of the edifice to which it is applied. Decorative style of Gothic Architec¬ ture : first introduced in the reign of Edward I., it was matured in England, and prevailed during the greater part of the 14th century. Its distinguishing features, says Dr. Whewell, are characterized by its window-tracery, geometrical in the early instances, flowing in the later; but also, and perhaps bet¬ ter, by its triangular canopies, crocketed and finialed; its niched buttresses, with triangular heads ; its peculiar mouldings, no longer a collection of equal rounds, with hollows like the early English, but an assemblage of various members, some broad, some narrow, beauti¬ fully grouped and proportioned. A capital with crumpled leaves, a peculiar base and pedestal, also belong to this style. Definitions in geometry :— 1. A point is that which hath no parts, or which hath no magni¬ tude. 2. A line is length without breadth. 3. A superficies has length and breadth. 4. A solid is a figure of three di- I mensions, having length, breadth, and thickness. Hence surfaces are extremities of solids, and lines the extremities of surfaces, and points the extremities of lines. If two lines will always coincide however applied, when any two points in the one coincide with the two points in the other, the two lines are called straight lines, or otherwise right lines. A curve continually changes its direction between its extreme points, or has no part straight. Parallel lines are always at the same distance, and will never meet, though ever so far produced. Ob¬ lique right lines change their dis¬ tance, and would meet, if pro¬ duced. One line is perpendicular to an¬ other when it inclines no more to one side than another. A straight line is a tangent to a circle when it touches the circle without cutting, when both are produced. An angle is the inclination of two lines towards one another in the same plane, meeting in a point. Angles are either right, acute, or oblique. A right angle is that which is made by one line perpendicular to another, or when the angles on each side are equal. An acute angle is less than a right angle. An obtuse angle is greater than a right angle. A plane is a surface with which a straight line will everywhere coincide; and is otherwise called a straight surface. Plane figures, bounded by right lines, have names according to the number of their sides, or of their angles, for they have as many sides as angles : the least number is three. An equilateral triangle is that whose three sides -are equal. An isosceles triangle has only two sides equal. A scalene triangle has all sides unequal. A right-angled triangle has only one right angle. Other triangles are oblique- angled, and are either obtuse or acute. An acute-angled triangle has all its angles acute. An obtuse-angled triangle has one obtuse angle. A figure of four sides, or angles, is called a quadrilateral, or quad¬ rangle. A parallelogram is a quadrilate¬ ral, which has both pairs of its 145 H DEF DEFINITIONS opposite sides parallel, and takes the following particular names:— A rectangle is a parallelogram, having all its angles right ones. A square is an equilateral rect¬ angle, having all its sides equal, and all its angles right angles. A rhombus is an equilateral parallelogram whose angles are oblique. A rhomboid is an oblique-angled parallelogram, and its opposite sides only are equal. A trapezium is a quadrilateral, which has neither pair of its sides parallel. A trapezoid has only one of its sides parallel. Plane figures, having more than four sides, are in general called polygons, and receive other parti¬ cular names according to the num¬ ber of their sides or angles. A pentagon is a polygon of five sides, a hexagon of six sides, a hep¬ tagon seven, an octagon eight, an enneagon nine, a decagon ten, an undecagon eleven, and a dodecagon twelve sides. A regular polygon has all its sides and its angles equal; and if they are not equal, the polygon is irregular. An equilateral triangle is also a regular figure of three sides, and a square is one-of four ; the former being called a trigon, and the latter a tetragon. A circle is a plane figure, bounded by a curve line, called the circumference, which is every¬ where equidistant, from a certain point within, called its centre. The radius of a circle is a right line drawn from the centre to the circumference. A diameter of a circle is a right line drawn through the centre, terminating on both sides of the circumference. An arc of a circle is any part of the circumference. A chord is a right line joining the extremities of an arc. DEF A segment is any part of a circle bounded by an arc and its chord. A semicircle is half a circle, or a segment cut off by the diameter. A sector is any part of a circle bounded by an arc, and two radii drawn to its extremities. A quadrant, or quarter of a cir¬ cle, is a sector having a quarter part of the circumference for its arc, and the two radii perpendicular to each other. The height or altitude of any figure is a perpendicular let fall from an angle or its vertex to the opposite side, called the base. The measure of any right-lined angle is an arc of any circle con¬ tained between the two lines which form the angle, the angular point being the centre. A solid is said to be cut by a plane when it is divided into two parts, of which the common sur¬ face of separation is a plane, and this plane is called a section. Definitions of solids :— A prism is a solid, the ends of which are similar and equal paral¬ lel planes and the sides parallelo¬ grams. If the ends of the prism are per¬ pendicular to the sides, the prism is called a right prism. If the ends of the prism are oblique to the sides, the prism is called arr oblique prism. If the ends and sides are equal squares, the prism is called a cube. If the base or ends are paral¬ lelograms, the solid is called a parallelopiped. If the bases and sides are rect¬ angles, the prism is called a rect¬ angular prism. If the ends are circles, the prism is called a cylinder. If the ends or bases are ellipses, the prism is called a cylindroid. A solid, standing upon any plane j figure for its base, the sides of which are plane triangles, meeting in one point, is called a pyramid. The solid is denominated from IN GEOMETRY. 146 DEGREE. DEM DEF its base, as a triangular pyramid is one upon a triangular base, a square pyramid one upon a square base, etc. If the base is a circle or an ellip¬ sis, then the pyramid is called a cone. If a solid be terminated by two dissimilar parallel planes as ends, and the remaining surfaces joining the ends be also planes, the solid is called a prismoid. If a part of a pyramid next to the vertex be cut off by a plane parallel to the base, the portion of the pyramid contained between the cutting plane and the base is called the frustum of a pyramid. A solid, the base of which is a rectangle, the four sides joining the base plane surfaces, and two oppo¬ site ones meeting in a line parallel to the base, is called a cuneus or j wedge. A solid terminated by a surface which is everywhere equally dis¬ tant from a certain point within it is called a sphere or globe. If a sphere be cut by any two planes, the portion contained be¬ tween the planes is called a zone, and each of the parts contained by a plane and the curved surface is called a segment. If a semi-ellipsis, having an axis for its diameter, be revolved round this axis until it come to the place whence the motion began, the solid formed by the circumvolution is called a spheroid. If the spheroid be generated round the greater axis, the solid is called a prolate spheroid. If the solid be generated round the lesser axis, the solid is called an oblate spheroid. A solid of any of the above structures, hollow within, so as to contain a solid of the same struc¬ ture, is called a hollow solid. Deflayrator, an instrument for pro¬ ducing intense light and heat. Deflection, a term applied to the dis¬ tance by which a curve departs from another curve, or from a straight line. Deflection , the deviation of a ship from its course. Deyree, the 360th part of the circum¬ ference of a circle; 60 geographical miles. Deyree, consisting of three figures of three places, comprehending units, tens, and hundreds. Delen (Derk Von) painted temples, saloons, and colonnades, and was a perfect master of architectural em¬ bellishment. De VOrme (Philibert) claims the ho¬ nour of inventing the volute now most commonly used, and com¬ plains that others pretend to it because Palladio and Serlio have spoken of it before him. Deliquice, according to Vitruvius, gut¬ ters, or drains. Delivery valve, the upper valve in the air-pump, or that through which the water is lifted into the hot well; also used when speaking of any sort of pump. Delphica, a table made of marble or bronze, and resembling a tripod. Delving, to dig. Delubrum, a font or baptismal basin. In antiquity, a church, chapel, temple, or consecrated place. Also that part of a Roman temple in which the altar or statue of the deity was erected. Demesne, lands belonging to the lord of a manor, and which are conti¬ guous to the manor-house. Demi-relievo, in sculpture, half-raised figures from the plane, as if cut in two, and only half fixed to the plane. Demi-tint is that shade seen when the sun shines on a house, or any other object, making an angle of nearly 45° on the ground plane, or when it shines more on the front than on the end. Dendrometer, an instrument for the measuring of trees. Dendiculus, a member in the Ionic and Corinthian entablatures, occur¬ ring between the zophorus and 147 h 2 •DEN DERRICK. DIA 1 _ : corona, and, properly speaking, a • part of the latter : so called be- i cause it represents denticuli, or i small teeth, placed at equal inter- ! vals apart. pentils , ornaments resembling teeth, used in the bed-mouldings of Ionic, , Corinthian, and Composite cornices. Departure, in navigation, is the east¬ ing or westing of a ship with re¬ spect to the meridian from which it departed or sailed; or it is the difference of longitude between the present meridian and where the last reckoning was made. Depression of the pole, in navigation : so many degrees as you sail from the pole towards the equator, so many you are said to depress the 1 pole, because it becomes so much lower in the horizon. | Derrick , a Cornish word for a miner. Derrick, in navigation, a tackle used at the outer quarters of the mizen- yard; it also signifies a prop or ! support to sheers, etc. j Derrick. Sheers and Gyn have one ' object in common,—to find a point or fulcrum in space to which the i pulley, in the shape of block and j tackle, is to be supplied ; and this is effected by the above, on one, | two, and three legs, respectively. ! In the derrick and sheers, stability is given by guys; in the gyn, they are unnecessary. Wherever these guys are used, great attention must be paid to their being well fixed, or i being (when requisite) duly eased- otf: when accidents occur from i neglect in this respect, they are generally very severe. ! Describent, in geometry, is the line or \ surface from the motion of which ; a surface or body is supposed to be generated or described. Descriptive geometry: the applica¬ tion of geometrical rules to the , representation of the figures and the various relations of the forms of bodies, in accordance to forms applicable to civil, military, and naval architecture, civil and me¬ chanical engineering, and the other arts that require more correct sci¬ entific representations than have hitherto been afforded to the stu¬ dent. Desiccation, the chemical operation of drying bodies, sometimes effected by drying in the air, sometimes in warm chambers, by the air-pump, etc. Design, a term in the fine arts, is em¬ ployed first to signify the art of drawing or representing in lines the form of any object; next it ex¬ presses that combination of inven¬ tion and purpose which enables the artist to compose a picture or a group, without reference to the material in which it is executed. Designing, the art of delineating or drawing the appearance of natural objects by lines. Destina, according to Vitruvius, a column or pillar to support an edi¬ fice. Detrampe, in painting, in water¬ colours. Device, an emblem or ensign for¬ merly borne on shields or em¬ broidered upon banners as a cogni¬ zance; contemporary, in the history of heraldry, with coat armour it¬ self. Device, in heraldry, painting, etc., any emblem used to represent a certain family, person, action, or quality, with a suitable motto, applied in a figurative sense. Diagonal, a line drawn from angle to angle. Diagonal rib, a projecting band of stone or timber passing diagon¬ ally from one angle of a vaulted ceiling across the centre to the opposite angle. Diagonal scale. Equidistant parallel lines cut all lines drawn across them into equal parts ; conse¬ quently a set of equidistant paral¬ lels laid down upon a ruler, with oblique lines of various lengths drawn across them, give with the compasses the means of imme¬ diately taking off various propor¬ tions of those lines. 148 DIA DIES. DIE Diagram, a delineation of geometrical figures; a mathematical illustration. Diagraphic Art, the art of painting or engraving. Dial, an instrument for the measuring of time; not mentioned in Scrip¬ ture before the reign of Ahaz, a.m. 3262. It is not clearly ascertained, even after this time, how the Jews divided the time by hours. The word hour occurs first in Tobit, which may confirm the opinion that the invention of dials came from beyond the Euphrates. Dialling. In all dials, the gnomon represents the axis of the earth; hence its angle with the horizon is the latitude of the place, and it lies in the plane of the meridian. There are a great variety of dials, according to whether they are hori¬ zontal, oblique, or vertical, and also depending on their aspect with re¬ ference to the sun, etc. Diamicton, according to Pliny, a term used by the Roman builders to designate a particular manner of constructing walls, the exterior of masonry and the interior of rub¬ ble. Diamond, a genus of precious stones of a fine pellucid substance of great hardness, and never debased by any admixture of earthy or other coarse matter. When pure, it is perfectly colourless. It is the most valuable of all gems, and is found only in the East Indies and the Brazils. It is constituted solely of carbon in its densest form. Diamond, glaziers', the pencil dia¬ mond, used in cutting glass, is a small fractured piece of diamond. Diaper ornament, of flowers, applied to a plain surface, either carved or painted: if carved, the flowers are entirely sunk into the work below the general surface; they are usually square, and placed close to each other, and are various in their pattern and design: it was first introduced in the early Eng- I lish style in some of the principal Gothic structures in England. 149 Diaper, a panel or flat recessed sur¬ face covered with carving or other wrought work in low relief; a kind of linen cloth, wrought with figures in the process of weaving. Diastyle, an arrangement of columns in Grecian and Roman architecture, in which the intercolumniation or space between them is equal to three or four diameters of the shaft. Diathyra, the vestibule before the doors of a Greek house, corres¬ ponding with the prothyra of the ; Romans. : Dialoni, the angle stones of a wall, . wrought on two faces, and which, stretching beyond the stones above and below them, form a good band or tie to the work. Diatoni, according to Vitruvius, the girders or band-stones formerly employed in constructing walls; corner stones. Diatretum, an enchased or curiously engraved vase or drinking-cup. Diaulon, a race-course, the circuit of which was two stadia, or 1200 feet; whence it was used to signify a measure of two stadia. Dicrotum, a boat with two oars. Die, the cube or dado of a pedestal. Die or Dye, a naked square cube: thus the body of a pedestal, or that part between its base and its cap, is called the die of the pe¬ destal. Dies, two pieces of hardened steel, which, when placed together, form a female screw (or a screw in a nut) which has cutting edges, used for making a screw on a bolt. Die-sinlcing: in the preparation of coined money and of medals, the most important feature is the en¬ graving of the die which is to form the stamp. The piece of steel is prepared with care, and brought to a soft state when about to be submitted to the hands of the en¬ graver. By the aid of small, fine, hardened steel tools, the engraver cuts away the steel until he has, produced, in cavity or intaglio, an DILAPIDATION. DIE exact reverse of the design for the medal or coin. Dieu et mon droit, —‘ God and my right,’—in heraldry; the motto of the royal arms of England, first assumed by Richard I. Differential thermometer. This in¬ strument was invented bv the same gentleman who contrived the pho¬ tometer and aetherioscope, and was used by him in his investi¬ gations on heat. Its principal use to the meteorologist is to make experiments on the light and heat of the moon, etc., by concentrating its rays, by a lens upon the sentient ball. This can only be done when the moon is on the meridian. It is peculiarly adapted for measuring the effect of radiation. Digester, a boiler invented by Papin for raising water to a higher tem¬ perature than the common boiling point, 212°: this is effected by forming a vessel somewhat resem¬ bling a kitchen pot; the mouth is formed into a flat ring, so that a cover may be screwed tightly on ; this cover is furnished with a safety- valve, loaded to the required pres¬ sure. Digit, a finger; a term employed to signify any symbol of number from 0 to 9 : thus ten (10) is a number of two digits. Digit, a measure of length, containing three-fourths of an inch. Diglyph, in architecture, an imperfect triglyph, with only two channels instead of three. Dilapidation, decay for want of repair; not unfrequently a point of dispute between a party in possession of a house and another party having an interest therein. Where there is a right to use lands or houses, ques¬ tions will arise as to the manner in which they ought to be used, and by whom dilapidations, whether caused by accident or decay, ought to be supplied. The rights of par¬ ties with respect to immovable property so closely border on each other, and the line of demarcation DIM between them is so indistinct, that one man, in the fancied exercise of his right, is continually liable to encroach upon or disregard the right of another. No person, how¬ ever absolute his property in laud, can put it to any use he pleases : his right to use it is restrained by the rights of his neighbour; he is bound to take care that his manner of using does not interfere with the inoffensive and profitable occu¬ pation by his neighbour of his land. (See the second edition, just pub¬ lished, of Mr. Gibbons’s elaborate work on the ‘ Law of Dilapidations and Nuisances.’) Dilettante (Italian),an ardent admirer of the fine arts. The Dilettanti Society, consisting of many dis¬ tinguished noblemen and gentle¬ men, has done much to rescue the noble monuments of Grecian art from otherwise inevitable ruin. Dilleuing,& Cornish word for a method of washing or finishing the dress¬ ing of tin in very fine hair sieves. Diluvial formation, the superficial deposits of gravel, clay, sand, etc., which lie far from their original sites on hills, and in other situ¬ ations, to which no forces of water now in action could transport them. Dilving, in dressing tin ore, shaking it in a canvas sieve, in a tub of water, so that the waste flows over the rim of the sieve, leaving the tin behind. Dimension, a term used in the same sense as degree. Dimensions. 1. General dimensions: size, magnitude, dimension, hulk, volume, largeness, massiveness. 2. Linear dimensions. 3. Central. Diminution, a term expressing the gradual decrease of thickness in the upper part of a column. Diminution of columns. The shafts of columns are diminished in dia¬ meter as they rise, sometimes from the foot itself of the shaft, some¬ times from one-quarter, and some¬ times from one-third of its height. The diminution at top is seldom 150 DIO DIVING-BELL. DIV less than one-eighth or more than one-sixth of the inferior diameter of the column. Dioptase or emerald copper, a crys- talized silicate of copper, the pri¬ mary form of which is a rhomboid. Its colour varies from emerald to hlackish green: it is translucent and brittle. Dioptra, a geometrical instrument employed in measuring the altitude of distant objects, and for taking the levels of a source of water intended to be conveyed to a distance by means of an aqueduct. Diorama, a mode of scenic exhibi¬ tion invented by two French artists, Daguerre and Bouton. Dip, in mining, the greatest inclina¬ tion of a stratum to the hori¬ zon. Di Palito is a light yellow ochre, affording tints rather purer in co¬ lour than the stone ochre, but less so than Naples yellow'. Many pleasing varieties of ochreous co¬ lours are produced by burning and compounding with lighter, brighter, and darker colours, but often very injudiciously and ad¬ versely to that simple economy of the palette which is favourable to the certainty of operation, effect, and durability. Diphryges, the scorial sediment, a calx of melted copper, gathered in the furnace when the metal was run out. Diplinthius, according to Vitruvius, two bricks thick. Dipping-needle, in navigation, a mag¬ netic needle, so hung that one end dips, or inclines to the horizon, and the other is proportionally elevated, forming an angle equal to the dip¬ ping of the needle at the place where the experiment is made. Dipping (among miners), the inter¬ ruption or breaking off of the vein of ore. Dipteral, having a double range of columns all round; a dipteral tem¬ ple usually had eight in the front row r of the end porticoes, and fifteen 151 at the sides, the columns at the angles being included in both. Dipteron, in ancient architecture, a temple surrounded with a double row of columns which form porti¬ coes, called wings or aisles. Dipteros, in Greek architecture, a temple with a double row of co¬ lumns on each of the four sides. Direct-action engine, an engine having the rotatory motion communicated to a crank placed directly over the cylinder, so as to save height, and lessen the weight of the engine : the term applies more particularly to marine engines. Discharging arch, an arch formed in the substance of a wall, to relieve the part which is below it from the superincumbent W'eight: it is fre¬ quently used over lintels and flat¬ headed openings. Discord, a term applied to painting when there is a disagreement of the parts or the colouring; when the objects appear foreign to each other, and have an unpleasing and unnatural effect. Disembogue, to pour out at the mouth of a river. Distemper, in painting, the w’orking- up of colours with something else besides mere water or oil. If the colours be prepared with the first, it is called limning ; and with the last, painting in oil. Distemper is a preparation of colours without oil, only mixed with size, w'hites of eggs, or any such proper glutinous or unctuous substance : with this kind of colour all the ancient pictures, before the year 1410, w r ere painted, as also are the celebrated cartoons of Raphael. Disti Salvi built the Baptisteryof Pisa. Ditriglyph, an interval between two columns, admitting two triglyphs in the entablature ; used in the Doric order. Dividiculum, in Rome, a tower on an aqueduct, containing a large reser¬ voir. Diving-bell, a machine contrived for safely lowering a man to any rea- DIV DOCKS. DOC sonable depth under water, so that he may remain there for a consi¬ derable time. Division of an Order. The general division of an Order being into two parts, namely, the column and en¬ tablature, the column is subdivided into three unequal parts, viz. the base, the shaft, and the capital. The entablature consists also of three unequal parts, which are, the architrave, the frieze, and the cor¬ nice. Each of these divisions con¬ sists of several smaller parts, which by their variety and peculiarity dis¬ tinguish the Orders from each other. Dock, a place artificially formed for the reception of ships, the entrance of which is generally closed by gates. There are two kinds of docks,—dry docks and wet docks : the former are used for receiving ships for repair, the latter for the purpose of keeping vessels afloat. Docks are enclosed artificial re¬ ceptacles for shipping, and are usually formed by excavation of the soil and constructed walls of ma¬ sonry, with inlets and gates for ad- mittingthepassageof vessels. Docks are usually distinguished as wet docks or basins and dry or graving docks. The former of these are already described under the head Basin ; the latter may be described as follows: Graving docks, in which repairs of vessels are effected, are con¬ structed of various dimensions, ac¬ cording to the class of vessel for which provision is intended. Se¬ veral splendid works of this kind have, within the last few years, been executed in the English dock¬ yards. One of these—the Eastern Dock in Hef Majesty’s Dockyard at Woolwich—is 282 feet in ex¬ treme length, 81 feet in width on the ground level, and 39 feet in the bed. The depth from the ground level to the bed is 27 feet. The inclined sides and curved end of the masonry are formed into a series of steps or altars, by which access is readily obtained to all parts of the dock, and fixing-places obtained for the struts with which the sides of the vessel under repair are maintained in an upright posi¬ tion, when the water is discharged from the dock. The river-wall of this structure was originally con¬ structed of concrete block-facings with rough concrete backings, ac¬ cording to a plan introduced into this country by Mr. Ranger ; but these were abandoned, and granite facings substituted, the entire mass of the wall being supported on timber-piling. The whole of the piers, apron, and coffer-dam walls were executed by tide-work, in the following manner: a small space was surrounded by sheet-piling, which was carried up from 6 to 8 feet above the level of low-water: into the enclosure thus formed a pipe from two 18-inch pumps, worked by a steam-engine, was led, and the pumps set to work as soon as the tide fell below the sheet-piling. The subsequent ex¬ cavation for the dock reached a bed of chalk, which was found to be sufficiently firm to dispense with the inverted arch of masonry usu¬ ally constructed beneath the bed of these docks, and the floor was con¬ sequently constructed of a hori¬ zontal paving of blocks of granite 2 feet in thickness, each stone, being joggled to the adjacent stones with dove-tail joggles of Valentia slate bedded in cement. The river water is admitted into the dock through a culvert 5 feet high and 3 feet wide, passing through each pier, and which culverts are worked by sluices of cast-iron. The front of the dock is closed with a caisson formed of plate-iron, fixed with rivets to ribs of angle-iron; the form of the caisson being similar to that of a vessel, namely, with a continuous keel along the bottom and up each end, and a swelling outline tapering towards the end keels, and reduced to a width nearly i 152 parallel in the dock-level. This continuous keel, which is of oak, and formed in two pieces, fits into a recess in the masonry at the en¬ trance of the dock, and the admis¬ sion of water into it is regulated by sluices and pumps. From the description given of graving docks, it will be under¬ stood that their action and efficiency depend upon the command of an adequate depth of water, and a sufficient rise and fall of tide to leave the vessel dry or to float her, as occasion requires. The use of these docks also compels the re¬ tention of the vessel during the action of the tide, and thus in¬ volves a considerable lapse of time, which sometimes cannot be af¬ forded for trifling repairs or ex¬ amination of a vessel in active ser¬ vice. For situations in which no tide exists, a different arrangement be¬ comes necessary, and a construction called a ‘ slip ’ is commonly substi¬ tuted for a graving dock. The slip which has been the most ex¬ tensively used is that known as ‘ Morton’s slip,’ and which was secured by a patent dated March 23, 1819, granted to T. Morton, for a method of dragging ships out of water for repairs, etc. This slip consists of an inclined plane, formed of timber framing laid upon suitable foundations of masonry, or cut in the surface of the rock. Upon this framing longitudinal metal racks are fixed, and a move- able carriage, upon which the ves¬ sel is received (by running the carriage to the lower part of the plane, beneath the water, and se¬ curing the vessel upon it), is fitted with cog-wheels, or other suitable apparatus for working upon these racks. The moving carriage con¬ sists of a succession of small strong blocks or carriages, any number of which may be connected together, according to the length of vessel to be hauled up. Each of these blocks or carriages, which are laid in corresponding pairs on each side of the central line of the slip, so as to leave a continuous inter- j mediate space to receive the keelj of the vessel, is fitted with rollers,* upon which it may be moved trans-; versely ; and thus the distance be¬ tween the two blocks of each pair,; or on each side of the centre, may; be adjusted according to the sec-, tional form of the ship. These motions are ingeniously effected with the aid of cross-ropes or lines ; which are fixed to the blocks, and by which means the entire action of the apparatus is much facili¬ tated. The combined carriage, : when loaded with the vessel, is hauled up the slip by cables at¬ tached to a drum apparatus, with suitable gearing fixed in a building at the head or upper end of the slip. The power required is of course in proportion to the weight to be hauled up, and to the rate of inclination of the slip, and is usu¬ ally supplied by a steam-engine. This principle is susceptible of; being extended, so as to provide berths for several vessels with only i one hauling-up slip and machinery.; For this purpose it has been sug¬ gested to construct a series of ’ frames arranged radially round a I centre, and capable of motion and of adjustment, with one slip con¬ structed in such a direction as to : correspond with a produced radius : of the same circle. This arrange- : ment, which would be similar to ; that of the polygonal engine-houses now erected on several lines of railway, offers great facilities for extended operations in the repair ■ of vessels, but of course requires great space for the construction of the radial frames. In order to provide for cases in which sufficient tidal difference cannot be had for raising vessels of deep draughts on to a dry dock, floating docks have been introduced in North America, and found to DOC DOCKS. DOC DOGS. DOC act satisfactorily. These floating docks are constructed with a buoy¬ ant bed or cradle, capable of sup¬ porting a vessel within the dock, with its keel above the surface of the water. This float or cradle is made in a box-like form, composed of strong logs, jointed firmly, and well caulked, so as to make it water-proof. The capacity of the float must be such that when freed from water by pumping, and loaded with the vessel, workmen, etc., it shall sustain the load with safety. The float moves within a recess of masonry, by which its motion is guided and secured. Suitable shores, blocks, struts, etc., are used in making the vessel steady within the float, which is fitted with valves in the lower part. The action of this floating dock is as follows: The cradle or float, being full of water (the valves being open), is sunk so that the vessel may be brought over it, and temporarily secured in position: the valves are then closed, and the pumps set to work to clear the water from the float, which rises in consequence, and brings up the vessel to a dry level. When the ship is again ready for sea, the opening of the valves admits the water, and sinks the float, leaving the vessel free above it to pass out of the dock. The docks and basins of London and Liverpool comprise some of the largest specimens of works of this kind. Those of the latter port were commenced in 1708, and con¬ sist of several docks of great ex¬ tent. The first public docks for merchant shipping in London were the West India Docks, opened in 1805, the great basin of which is 420 yards in length, and 230 yards in width. This is connected with the river by another basin of about three acres in area. The London Docks were commenced soon after the West India Docks, and opened in the same year, viz. 1805. The principal basin of these docks is DOG 420 yards in length, and 276 yards in width. The East India Dock for unloading inwards is 470 yards in length, and 173 yards in width ; and that for loading outwards is 260 yards in length, and 140 yards in width. The St. Katherine’s Docks occupy an area of 24 acres. Dodecagon, in geometry, a figure of twelve angles and sides. Dodecahedron, in geometry, one of the regular bodies comprehended under twelve equal sides, each of which is a pentagon. Dodecastyle, a building having twelve columns in front. Dogs, or andirons, creepers, braziers, etc. Long after the general intro¬ duction of chimneys, wood was the ordinary fuel for all sorts of apart¬ ments. Coals formed no part of the ‘ liveries,’ but wood was com¬ monly included in them. A ‘ cra¬ dle for sea-coal’ is however fre¬ quently mentioned as belonging to the chief rooms in superior houses, though the usual way of warming, or rather airing, bed-chambers was with braziers or chafing dishes. Andirons are a larger and higher sort of irons, made to support the wood, and have usually long necks rising up before, to prevent the wood from falling upon the floor. Creepers are smaller and lower irons with short necks, or none at all, which are placed between the andirons, to keep the ends of the wood and thebrandsfrom theliearth, that the fire may burn more freely. Dog-kennel, a lodgement for dogs kept for the purpose of field sports: it is almost as invariable an ap¬ pendage to the manor-house as it was formerly to the baronial castle. Bishop Percy observes, “ that a nobleman in the dark ages, retired within his castle, had neither books, nor newspapers, nor literary correspondence, nor visits, nor cards, to fill up his leisure : his only amusements were field sports; nor did the love for these decline in the Tudor period.” 154 DOMES. DOM DOG Dog-wood, a small underwood, free from silex : small splinters are used by watch-makers for cleaning out the pivot-holes of watches; it is also used by butchers for making skewers. Dogger, a ship of about eighty tons burden, with a well in the middle, to bring fish alive to shore. Dolomite, massive magnesian lime¬ stone, used by the ancient sculptors in their best works. Dolphin, a technical term applied to the pipe and cover at a source for the supply of water. Dome, a term applied to a covering of the whole or part of a building: the word dome is strictly applied to the external part of the spheri¬ cal or polygonal roof, and cupola to the internal part. Dome or cupola, a roof, the base of which is a circle, an ellipsis, or a polygon, and its vertical section a curve line, concave towards the in¬ terior. Hence domes are called circular, elliptical, or polygonal, according to the figure of the base. The most usual form for a dome is the spherical, in which case its plan is a circle, the section a seg¬ ment of a circle. The top of a large dome is often finished with a lantern, which is supported by the framing of the dome. The interior and exterior forms of a dome are not often alike, and in the space between, a staircase to the lantern is generally made. According to the space left between the external and internal domes, the framing must be designed. Sometimes the framing may be trussed with ties across the opening; but often the interior dome rises so high that ties cannot be inserted. Accord¬ ingly, the construction of domes may be divided into two cases: viz. domes with horizontal ties, and those not having such ties. Dome, in locomotive-engines, the conical part of the boiler, forming a steam-chamber, and terminating the top of the fire-box part. In a locomotive-engine the safety- valves are usually placed on the top of the dome or the body of the boiler. Dome-cover, in locomotive-engines, the brass or copper cover which encloses the dome, to prevent the radiation of heat. Dome Cathedral of Pisa, the first model of that Tuscan style of ar¬ chitecture, so solid, grave, and im¬ posing, neither Greek nor Gothic, was begun in the eleventh century; and in the thirteenth was founded the majestic church of Santa Maria dei Fiori at Florence, of which the dome equals in size that of St. Peter’s at Rome, and was its model. Dome of St. Paul's Cathedral (the) is elliptical, and built of wood; it is confined by strong chains, consist¬ ing of iron bars: that of the Pan¬ theon at Rome is nearly circular, and its lower parts are so much thicker than its upper parts as to afford sufficient resistance to their pressure; they are supported by walls of great thickness, and fur¬ nished with many projections which answer the purpose of abutments and buttresses. Domes in Asia are probably more ancient than in Italy. At Lanker- rood, at Dhay-nain, at Sin-sin, five or six days’ journey south of Tehe¬ ran, in Persia, the towns are all de¬ serted : there are about a hundred large dwelling-houses quite entire, of a very singular construction. Each edifice stands separate, and is constructed of several central arches supporting a pointed dome; while smaller divisions project from the body of the building, also arched, and the whole finished with the greatest neatness, having remains of stucco-painted walls within. It is probable that the arch and vault and dome were not unknown to the nations in the East, beyond the Indies, in a very remote age; but in Greece and in Asia Minor 155 DOM DOMESTIC BUILDINGS AND CASTLES. DOM there are no traces of them before their introduction by the Romans. To the Romans they were familiar at a very early period of their his¬ tory ; a knowledge of which they borrowed perhaps from the Etrus¬ cans, or from the supposed extinct people who possessed a city on the site of Rome itself, before the Romans. Domestic Architecture in England. At the termination of the York and Lancaster wars, the fortified style of architecture was gradually aban¬ doned in England; and as we had no oilier model of domestic archi¬ tecture than the gable and the cot¬ tage, by the duplication of this simple form, in various positions, was constructed what has been called the Old English Manor- house style. If we take a common two-floored English gable and cot¬ tage, add to it one, two, or three cottages side by side, of the same size, and, in order to gain rooms out of the roof on the sides of this double or triple cottage, raise gable ends either projecting from the ground to the top of the roof, or merely raised from the eaves-drop; if we insert broad low windows, divided by simple wooden or stone mullions, in these projecting gable ends, and similar windows at the ends of this double or triple cot¬ tage ; ornament the inclined sides of the gable ends above the eaves¬ drop by steps or small pinnacles, or both; then add a parapet, plain or embattled, we have a manor-house in the most florid style. Many such houses came afterwards to be adorned by a centre of architec¬ tural decoration, in which Roman, Grecian, and Gothic were strangely mixed. There is, however, a cer¬ tain degree of antique-like gran¬ deur in such houses, which pro¬ duces a very striking impression. This step towards a better style took place before the time of Inigo Jones. “The mansion at South Elmham, when entire, formed a quadrangle, as usual, of which stables and offices made up a part. The do¬ mestic and ecclesiastical styles are ] singularly combined in this build- i ing, though the latter seems to predominate; and the occasional discovery of old floor-stones, of a sepulchral character, intimates that the projecting porch led to the chapel of the dwelling, not into the hall; and yet the ceilings of the chambers where the two wings and upper windows are observed, on the right hand of the porch, are flat, divided into small squares by the girders above, and covered with plastered mouldings, in the manner usually seen in dwellings of an early period.” Domestic buildings and castles. The towns and ordinary houses of the Normans were entirely built of wood, and, for the most part, are so to this day. Their castles, having but one destination, that of defence, aimed at nothing but strength in their plan or con¬ struction. A site was also selected which was already fortified by nature. The plan of the Norman castles was as nearly the same as the di¬ versity of ground would allow. The principal feature was always the keep, which contained the apartments of the lord of the cas¬ tle, and was also meant to be the last refuge of the garrison, if the outer works were forced. The keep was usually raised on an artificial mound, or placed on the edge of a precipice. The walls, strengthened in every way that art could devise, were of immense thickness, and composed of grouting poured in between two solid walls of stone. The facing consisted sometimes of irregular courses, and sometimes of small squared stones, after the Ro¬ man manner. Ashler was usually introduced at the angles of the building. The window's were few, and little more than chinks, unless 156 DOM DOORS. DOO cimen taken from the church of St. Botolpli, at Cove, in the county of Sutfolk. Dornus, a private house occupied by a single proprietor and his family. Doors {Antique). The Greeks in the temple of Minerva Polias, at Athens, and also the Romans in the temple of Vesta, or the Sibyl, at Tivoli, made the doors and win¬ dows smaller at top than at bot¬ tom : the architrave or dressing always constituted an agreeable decoration when in character with the building. Those of the win¬ dows in the Grecian temple have a projection, or what is sometimes termed a knee,at their upper angle; while those of the temple of Vesta, whose apertures have the same form, continue without interrup¬ tion, and are surmounted by a cor¬ nice ; but the cornice above the door is separated from the archi- very high up, or turned to the court. The door of entrance could only he reached by a staircase. Under the keep were usually vaults, or dungeons, for the recep¬ tion of prisoners. The keep was enclosed in two courts surrounded by walls flanked with towers. The tower at the entrance was called the barbican, and served at once for an outwork and post of obser¬ vation. The whole fortress was defended by a moat. The remains of the Norman cas¬ tles which exist scarcely afford any specimens of early Norman con¬ struction, almost all these castles having been besieged, destroyed, and rebuilt, over and over again. The keep of Falaise is perhaps the only castellated remnant of early Norman times. The castle of Gi- zors, which was built by William Rufus, retains nothing of its origi¬ nal construction. Doorway ( Anglo- Norman ). The Anglo - Norman buildersbestowed much pains and evinced consider¬ able artistic skill in very elaborately ornamenting the portal entrances to churches in their style of ar¬ chitecture, by a profusion of orna¬ mental mouldings and of sculpture. Very many ex¬ amples are to be met with in great variety in several of the counties of England, particu¬ larly in the coun¬ ties of Norfolk and Suffolk. The example repre¬ sented in the an¬ nexed engraving is a beautiful spe- 157 DORIC ORDER. DOO trave by a frieze, while the cornice of the windows joins the archi¬ trave. In the temple of Minerva, the architrave of the windows rests only on a plain socle ; those of the temple of Vesta rest also on a socle or support, the face of which is sunk. Doors ( Modern ). There are two doors, designs of Vignola, which offer in their profiles and propor¬ tions a happy medium between the antique and modern compositions ; and all other designs of this kind are either derived from them, or pos¬ sess a vague character which ren¬ ders them unworthy of imitation. There are breaks in the archi¬ trave, as in those of the temple of Minerva Polias; and the ter¬ mination or low r er extremity of these breaks determines the length of the consoles, which gives har¬ mony to the arrangement. These consoles are also placed against a second architrave, beyond which the first projects. The design of the door of the church of St. Lo¬ renzo is more regular. Doorways. In the Gothic, and the architecture of the middle ages, doorways are striking and impor¬ tant features, affording in the cha¬ racter of the mouldings and orna¬ ments the style and period of the edifice. Doric Order. The Doric order, says Palladio, w r as invented by the Do¬ rians and named from them, being a Grecian people which dwelt in Asia. If Doric columns are made alone without pilasters, they ought to he seven and a half or eight diameters high. The intercolumns are to be little less than three diameters of the columns ; and this manner of spacing the columns is by Vitruvius called Diastylos. The ancients employed the Doric in temples dedicated to Minerva, to Mars, and to Hercules, whose grave and manly dispositions suited well with the character of this order. Serlio says it is proper for churches dedicated to Jesus Christ, DOR to St. Paul, St. Peter, or any other saints' remarkable for their forti¬ tude in exposing their lives and suffering for the Christian faith. Le Clerc recommends the use of it in all kinds of military build¬ ings ; as arsenals, gates of fortified places, guard-rooms, and similar structures. It may likewise he employed in the houses of generals or other martial men,—in mauso¬ leums erected to their memory, or in triumphal bridges and arches built to celebrate their victories. Vitruvius himself makes the Do¬ ric column in porticoes higher by half a diameter than in temples ; and most modern architects have, on some occasions, followed his example. In private houses, there¬ fore, it may be 16£, 16^, or 16§ modules high ; in interior decora¬ tions, even seventeen modules, and sometimes perhaps a trifle more ; which increase in the height may he added entirely to the shaft, as in the Tuscan order, without changing either the base or capital. The entablature, too, may remain un¬ altered in all the aforesaid cases ; for it will he sufficiently bold with¬ out alteration. The height of the Doric column, including its capital and base, is sixteen modules; and the height of the entablature, four modules; the latter of which being divided into eight parts, two of them are given to the architrave, three to the frieze, and the remaining three to the cornice. In most of the antiques, the Doric column is executed without a base. Vitruvius likewise makes it without one; the base, accord¬ ing to that author, having been first employed in the Ionic order, to imitate the sandal or covering of a woman’s foot. Scamozzi blames this practice; and most of the moderns have been of his opi¬ nion, the greatest part of them having employed the Attic base in this order. 158 DOR DOVE-TAIL. Dorman tree , a large beam lying across a room ; a joist, or sleeper. Dormer window, a window pierced through a sloping roof, and placed in a small gable which rises on the side of the roof. Dormitory, a sleeping apartment; a term formerly applied to the sleep¬ ing-room of the inmates of monas- j teries and other religious houses. Dormond, a large beam lying across a room; a joist, or sleeper : same as Dorman. Doron, a hand-breadth, or palm: among the Greeks, their bricks or tiles were termed tetradoron, four hands’ breadth, or pentadorou, five hands broad; the word also im¬ plies a gift: hence, probably, the origin of the English word dowry. Dorture, a place to sleep in, a bed¬ chamber. “ He led us to a gallery' like a dorture.” Dosel, hangings round the walls of a hall, or at the east end, aud some¬ times the sides, of the chancel of a church, made of tapestry or car¬ pet-work ; used also in churches, and frequently richly embroidered with silks, and gold and silver. Dosel, ornamental and rich stuff for the back of a chair, a throne, or a screen of ornamental woodwork. Double-acting pump, a pump which lifts and forces water at the same time, by means of a solid piston, and an entrance and exit-valve communicating with each side. Double-beat valve, a valve used in Cornish engines and water-works. It has two beats, or seatings, one above the other; the bottom one is similar to an ordinary circular valve seating ; the top one is some¬ what less in diameter than the bottom one, and is supported from it by ribs, and forms a cover nearly the size of the inner passage. A shell with two beats to correspond with the seatings shuts the sides; when raised (which requires but little power, as the fixed cover before mentioned bears nearly all the pressure, its diameter being DRA nearly equal to that of the shell) the steam or water escapes at the sides both of the top and bottom beat. Double-cylinder engine, a marine en¬ gine with two cylinders placed at right angles to the crank-shaft, and at a small distance apart, to give space for the vibration of the rod connecting the crank to the long end of a shaped cross-head, which slides in grooves between the cy¬ linders ; the upper ends of the cross-head are connected to the piston-rods. This form of engine is patented by Messrs. Maudslay. Doucine, a moulding, concave above and convex below. Dove-tail, in carpentry, a method of joining two boards together by letting one piece into another in the form of the tail of a dove, when that which is inserted has the ap¬ pearance of a wedge reversed. Dove-tailing, a method of fastening together twrn pieces of metal or W'ood by projecting bits cut in the form of dove-tails in one piece, to fit into corresponding hollows in the other. Dowel. A round dowel or coak is the piece of timber to which the felloes of a carriage-wheel are united. Dowsing cheeks, in sliip-building, pieces fayed across the apron, and lapped on the knightheads or in¬ side stuff above the upper deck. Drabler, a small topsail. Drabs,m salt-works, a kind of wooden box for holding the salt wdien taken out of the boiling pan. Draft-engine, an engine used for pumping. Drag-bar, a strong iron rod with eve-holes at each end, connecting a locomotive engine and tender by means of the drag-bolt and spring. Drag-bolt, the strong bolt coupling the drag-bar of a locomotive engine and tender together, and remov¬ able at pleasure. Drag-hook and chain, the strong chain and hook attached to the front of DRA DRAINAGE. DRA the engine buffer-bar, to connect it on to any other locomotive en¬ gine or tender; also attached to the drag-bars of goods-waggons. Drag-link, a link for connecting the cranks of two shafts ; it is used in marine engines for connecting the crank on the main-shaft to that on the inner paddle-shaft. Drag-spring, a strong spring placed near the back of the tender. It is attached by the ends to the drag- bar which connects the engine and tender, and by tbe centre to the drag-bar which connects the train to the tender. Dragon-leams are two strong braces which stand under a breast-sum¬ mer and meet in an angle on the shoulders of the king-piece. Dragon's blood (colour), a resinous substance brought from the East Indies. It is of a warm semi-trans¬ parent, rather dull-red colour, which is deepened by impure air, and darkened by light. There are two or three sorts, but that in drops is the best. White lead soon de¬ stroys it, and it dries with extreme difficulty in oil. It is sometimes used to colour varnishes and lac¬ quers, being soluble in oils and alcohol; but notwithstanding it has been recommended as a pigment, it does not merit the attention of the artist. Drainage of marshes and fen lands. The steam-engine is used to raise the water above the level of those lands which lie too low to be drained by natural outfall, and also in situ¬ ations where the fall is not sufficient to carry off the superfluous water in time to prevent damage to the crops. Mr. Glynn has applied steam- power to the drainage of land in fifteen districts, all in England, chiefly in Cambridgeshire, Lincoln¬ shire, and Norfolk. The quantity of land so drained amounts to more than 125,000 acres, the engines em¬ ployed being seventeen in number, and their aggregate power 870 horses: the size of the engines varies from 20 to 80 horses. Mr. Glynn was also engaged in draining by steam power the Hammerbrook district, close by the city of Ham¬ burgh ; and in another level near to Rotterdam, an engine and ma¬ chinery with the requisite buildings have been erected from his plans by the Chevalier Conrad, and the works successfully carried into effect. In British Guiana the steam-en¬ gine has been made to answer the double purpose of drainage and irri¬ gation. Some of the sugar-planta¬ tions of Demerara are drained of the superfluous water during the rainy season, and watered during the dry season. In many of the swampy levels of Lincolnshire and Cambridgeshire, much had been done to carry off the water by natural means, and many large cuts had been made and em¬ bankments formed, especially in the Bedford Level, which alone contains about 300,000 acres of fen-land; the Great Level of the fens contains about 680,000, for¬ merly of little value, but now rich in corn and cattle. The general plan is to carry away the water coming off the higher grounds, and prevent it, as much as possible, from running down into the marsh by means of the catchwater drains, leaving the rain alone which falls upon the district to be dealt with by mechanical power. As the quantity of rain falling on the Great Level of the fens seldom exceeds 26 inches in the year, and about two-thirds of this quantity is carried off by evaporation and absorption, or the growth of plants, it is only in extreme cases that 2 inches in depth require to be thrown off by the engines in any one month, which amounts to cubic foot of water upon every square yard of land, or 7260 feet to the acre. The standard and accepted mea¬ sure of a horse’s power is 33,000fts. DRAINAGE. IDRA raised 1 foot high in a minute, or 3300fbs. raised 10 feet high in the same time ; and as a cubic foot of water weighs 62^tbs., and a gallon of water 10ibs.,so one horse’s power will raise and discharge, at a height of 10 feet, 330 gallons, or 52 T 8 y cubic feet of water in a minute. Consequently this assumed excess of 7260 cubic feet of water fallen upon an acre of land will be raised and discharged at an elevation of 10 feet in about two hours and twenty minutes. If the quantity of land be 1000 acres of fen or marsh, with the upland waters all banked out, the excess of rain, ac¬ cording to the foregoing estimate, will amount to 726,000 cubic feet. A steam-engine of 10-horse power will throw off this water in 232 hours, or in less than twenty days, working twelve hours a day. This calculation has been found fully supported in practice. Although the rain due to any given month may fall in a few days, yet in such case much of it will be absorbed by the ground ; and the drains must be made of sufficient capacity to receive and contain the rain as it falls; besides, in case of necessity, the engine may be made I to work twenty hours a day in¬ stead of twelve, until the danger be past. The main drains have generally been cut 7\ feet deep, and of width sufficient to give them the required capacity to contain the excess of rain, and to bring the water freely down to the engine. In some in- I stances, where the districts are ex¬ tensive and their length great, it i has been found necessary to make them somewhat deeper. In all cases where it has been requisite to use steam-power, Mr. Glynn has applied scoop-wheels to raise the water. These scoop-wheels somewhat resemble the undershot I wheel of a water-mill, but instead of being turned by the impulse of the water, they are used to lift it, DRA and are kept in motion by the steam-engine. The floats or ladle-boards of the wheels are made of wood, and fitted to work in a trough or track of masonry ; they are generally made 5 feet in length, that is to say, they are immersed 5 feet deep in the water, and their width or horizontal dimension varies from 20 inches to 5 feet, according to the power of the engines employed, and the head of water to be overcome. The wheel-track at the lower end com¬ municates with the main drain, and at the higher end with the river; the water in the river being kept out by a pair of pointing doors, like the lock-gates of a canal, which close when the engine ceases to work. The wheels themselves are made of east-iron, formed in parts for convenience of transport. The float-boards are connected with the cast-iron part of the wheel by means of oak-starts, which are stepped into sockets cast in the circumference of the wheel to re¬ ceive them. There are cast-iron toothed seg¬ ments fitted to the wheel, into which works a pinion fixed upon the crank-shaft of the steam-en¬ gine. When the head of water in the river or delivering drain does not vary much, it is sufficient to have one speed for the wheel; but where the tide rises in the river, it is desirable to have two speeds or powers of wheel-work, the one to be used at low rate, the other more powerful combination to act against the rising tide. But in most cases it is not requisite to raise the water more than 3 or 4 feet higher than the surface of the land intended to be drained; and even this is only necessary when the rivers are full between their banks, from a continuance of wet weather, or from upland floods. In some instances, the height of the water in the rivers being af¬ fected by the tide, the drainage by 161 DRA DRAINAGE. DRA natural outfall can take place only during the ebb; and here, in case of long continuing rains, the natu¬ ral drainage requires the assistance of mechanical power. It has been stated that the main drains have generally been made 7|feet deep, or more in larger dis¬ tricts, so that the water may never rise higher than within 18 inches or 2 feet of the surface of the ground, and the ladles or float- boards dip 5 feet below the water, leaving a foot in depth below the dip of the wheel, that the water may run freely to it, and to allow for the casual obstruction of weeds in the main drain, which, if it be sufficiently capacious and well formed, will bring dow n the water to the engine with a descent of 3 inches in a mile. Suppose then that the wheel dips 5 feet below the surface of the water in the main drain, and that the water in the river into which this water must be raised and discharged has its level 5 feet above that in the drain, the wheel in such case will be said to have 10 feet head and dip, and ought to he made 28 or 30 feet in diameter. Mr. Glynn has found it practi¬ cable to throw out the water against a head of 10 feet with a dip of 5 feet, that is to say, 15 feet of head and dip, with a wheel of 35 feet in diameter; but in another engine, more recently erected, he has made the wheel 40 feet in diameter. The engine that drives this wheel is of 80-horse power, and is situ¬ ated on the Ten-mile Bank, near Littlepool, in the Isle of Ely. The largest quantity of water delivered by one engine is from Deeping Fen, near Spalding ; this fen con¬ tains 25,000 acres, and is drained by two engines, one of 80 and one of 60-horse power. The 80-horse engine has awheel of 28 feet in diameter, with float- boards or ladles measuring 5-| feet by 5 feet, and moving with a mean velocity of 6 feet per second ; so that the section of the stream is 2?5 feet, and the quantity dis- 1 charged per second 165 cubic feet; I equal to more than 4 £ tons of water I in a second, or about 16,200 tons 9 of water in an hour. It was in 1825 that these two 1 engines were erected, and at that |j time the district was kept in a half- !| cultivated state by the help of forty- n four windmills, the land at times ) being wholly under water. It now I'j grows excellent wheat, producing i from four to six quarters to the M acre. In many districts, land has 1 been purchased at from £ 10 to £20 1 an acre, by persons who foresaw the I consequences of these improve- j> ments, and which they could now p sell at from .£50 to £70 an acre. ;| This increase in value has arisen, j not only from the land beingcleared from the injurious effects of the i water upon it, but from the im- | proved system of cultivation it has I enabled the farmers to adopt. The fen-lands in Cambridgeshire and great part of the neighbouring : counties are formed of a rich black earth, consisting of decomposed vegetable matter, generally from 6 feet to 10 feet thick, although in some places much thicker, resting upon a bed of blue gait, containing clay, lime, and sand. Draining, as applied to lands, towns, and buildings, is the art of drawing or conveying away refuse liquid and other matters, the accumula¬ tion of which would be detrimental to animal and vegetable existence. In that department which re¬ lates to lands, draining compre¬ hends also the methods of irriga¬ ting or supplying water for agri¬ cultural purposes, for which the natural supply is inadequate. Re¬ ferring to towns, and buildings, this art includes also, for the purpose of thorough cleansing, the artificial supply of water. According to this comprehensive definition, which will be found to 162 DRA DRAINAGE OF LANDS. DRA have greater practical convenience than any more limited one, Drain¬ ing comprises observations of the relative levels of districts and of their geological structure ; of the several sources of water, and the amount of their products ; and the construction and arrangement of all the artificial appliances required for the supply, conduct, and dis¬ posal of water, and for conveying and discharging refuse matters generally. The sources of water are rains and the ocean. The former pass¬ ing into the earth, descend along the lower surfaces, and form streams and rivers ; or penetrate into some permeable media, and accumula¬ ting in subterranean depositories, form springs. An examination of the superficial and structural fea¬ tures of the soil enables us to esti¬ mate the quantity of water present in a district, and to determine the means that will be available for supplying the deficiency or dis¬ charging the excess. The same observations afford general infor¬ mation required in order to arrange the artificial channels, drains, sewers, etc., by which the supply and refuse matters are to be con¬ ducted and disposed of. Soils are retentive of water in proportion to their density and compactness. Thus, on clay-lands an excess of water is commonly found, while, from the porous tex¬ ture of gravel and loose sand, water passes rapidly away, and they are thus kept in a dry condition. The size of the channels or drains, by which the water is con¬ ducted away, will be adapted to the superficial extent to be drained, and the quantity of water due to the district, as computed from its relative position and structure. The construction of the drains will depend upon the materials of the soil, and the proximity of those suitable for the purpose. Generally, covered drains are far preferable to open ones ; and those formed with a duct of earthen piping are more durable and economical than any others. The implements used are rods and levels, for measuring dis¬ tances and ascertaining inclinations of surface;—tools for boring the soil, to examine substrata, and de¬ tect springs, consisting of augers, chisels, punches, etc. ; — spades, shovels, and picks of various forms and dimensions ; and hoes, scoops, etc., for clearing out and finishing the form of drains. For the draining of towns and buildings, including the artificial supply of water, the best available sources—such as rivers and springs —are resorted to, and the advan¬ tageous use of these will require a careful consideration of the quali¬ ties of the water obtained, and its suitability for domestic and manu¬ facturing purposes. Arrangements are required for making the water furnished by rains available to the full extent, and rendering it and all other waters fit for use by subsi¬ dence, filtration, and purification. For discharging the refuse mat¬ ters from houses and other build¬ ings, and from streets and public thoroughfares, drains and sewers of various forms and materials are to be selected, made of ample di¬ mensions and permanent construc¬ tion, with such vertical inclination, and so arranged, that their con¬ tents shall always have a tendency to run off, and never suffer inter¬ ference from the discharge of other channels. As a final point to be observed in any system of town-drainage, that of the ultimate disposal of the refuse matters is one of the highest importance in both a sanatory and an economical point of view. Col¬ lected in proper reservoirs, and judiciously treated, these matters may be distributed in fertilizing streams over the fields and the gardens of the suburbs, and will thus realize immense value in im- DRAWBRIDGE. DRA DR AWE RIDGE. DRA proved and augmented crops: al¬ lowed to accumulate in cesspools beneath human dwellings, they en¬ gender malignant and fatal disease, and if finally discharged into a river, by way of getting rid of them, they pollute waters otherwise wholesome, and, in dry seasons, send forth from the banks the most unhealthy gases. Drana, a drain or watercourse. Draught ,in ship draughting,the draw¬ ing or design by which the ship is to be built, which is generally by a scale of oue-fourth of an inch to a foot. Draute-chamber, a retiring or with¬ drawing room. Draw-bore , the pinning a mortise and tenon, by piercing the hole through the tenon nearer to the shoulder than the holes through the cheeks from the abutment in which the shoulder is to come in contact. Draw-bore pins, pieces of steel in the shape of the frustum of a cone, somewhat tapered, and inserted in handles with the greatest diameter next to the handle, for driving through the draw-bores of a mor¬ tise and tenon, in order to bring the shoulder of the rail close home to the abutment on the edge of the style: when this is effected, the draw-bore pins, when more than one are used, are taken out singly, and the holes filled up with wooden pegs. Drawbridge. All drawbridges are composed of two distinct parts, viz. the platform, which revolves on a horizontal axis, acting as a barrier or gate when in a vertical position, and becoming a bridge when in a horizontal position ; and the con¬ trivance necessary to balance the platform in every position. The equilibrium should be such that friction is the only force to be overcome in raising or lowering the platform. The chief difference between drawbridges lies in the arrange¬ ment of this latter contrivance; for the platforms only differ in small details of construction, which have very little influence on the qualities which are essential to the arrange¬ ment of the balancing apparatus. These qualities remain the same, | whether the drawbridges are used for closing communications in for- ! tified works, or merely for forming passages across navigable canals. 1 They are principally as follows:— 1st. The whole system should possess sufficient strength to be i perfectly free from danger in all positions and at all times, and should therefore be constructed i of solid and lasting materials. 2nd. A small number of men should be able to raise or lower the bridge in a short space of time. This quality requires all the parts to be in equilibrium when friction is not considered. 3rd. The machinery for raising and lowering the bridge should not obstruct the communications either in front or in rear of the buttresses ! of the gateway where it is placed; and also the space formed by rais¬ ing the bridge should be as wide j as possible, for this space consti- ; tutes the chief use of the bridge. ! 4th. The counterpoise and the machinery attached to it should be raised as little as possible above the platform when vertical, in or¬ der that it may not be much ex¬ posed to an enemy’s fire, and that it may be easily covered by the ad¬ vanced works; besides that, by raising it, the expense of construct¬ ing and the inconvenience of work¬ ing the machinery are increased, and the strength of the gateway or postern is sometimes diminished. 5th. The counterpoise and its machinery should not be much be¬ low the level of the ground, and particularly very little below the j level of the surface of the water in wet ditches. At all events, the descending parts should be enclosed in narrow shafts of masonry secure j from damp. In order not to weaken 164 DREDGING. DRA the postern walls, they should be at least 3 feet in rear of them. Drawing is the art of representing objects on a flat surface by lines describing their forms and contours alone, independently of colour or even shadow, although the latter is closely allied with drawing, both in i practice and theory. Drawings in pencil are sometimes re¬ quired to be fixed: this can be done by using water-starch -made to the consistency of that employed by laundresses: it should be ap¬ plied with a broad camel's hair brush, as in varnishing. Isinglass, size, and rice-water are sometimes used, but are not so good as the first-named substance. Dredge’s Suspension Bridge consists in making the chains of sufficient magnitude and strength at the ! points of suspension to support I with safety the greatest permanent and contingent load to which, un¬ der the circumstances of locality, they are ever likely to be exposed ; and from thence, to taper or dimi¬ nish them gradually to the middle of the bridge, where the strain be¬ comes essentially evanescent. The gradual diminution of the chains, however, is not the only peculiarity which characterizes this mode of construction, and marks its utility. The suspending-rods or bars that support the platform, or roadway, instead of being hung vertically or at right angles to the plane of the horizon, are inclined to it in angles which vary in magnitude from the abutments to the middle of the bridge, where the obliquity, as well as the stress upon the chains, at¬ tains its minimum value. 1 j Wedging machines , mechanical con- t trivances placed in the hull of a vessel, and floated in situations for the dredging and clearing away of deposited matter from the beds of rivers, canals, harbours, basins, etc. Some machines for these purposes are to be compared to harrows or shovels, which loosen the deposit I.- DRI preparatory to its removal either by the action of the tide or stream ; but for the more general purposes of dredging, vast improvements have been effected. The machinery of the best construction is described in Weale’s ‘ Quarterly Papers on Engineering.’ Dressings, the mouldings and sculp¬ tured decorations of all kinds which are used on the walls and ceilings of a building for the purpose of ornament. Drift, a piece of hardened steel, notched at the sides and made slightly tapering: it is used for enlarging a hole in apiece of metal to a particular size by being driven through it. Drift, the horizontal force which an arch exerts with a tendency to overset the piers from which it springs. Drifts, in the sheer draught, are wffiere the rails are cut off and ended with a scroll. Pieces fitted to form the drifts are called drift- pieces. Driftway, in mining, is a passage cut under the earth from shaft to shaft. Drill, a tool for cutting a circular hole in a piece of metal. Drilling machine, a machine for cut¬ ting circular holes in metal by means of a revolving drill. Drilling, the art of boring small holes. Drilling may be effected in a lathe. The drill is screwed upon the spin¬ dle, so that its point shall turn ex¬ actly opposite that of the screw in the shifting head. Various inge¬ nious improvements have recently been made. Drip, the projecting edge of a mould¬ ing channeled beneath, so that the rain will drip from it: the corona of the Italian architects. Dripstone, called also the ‘ label,’ ‘ weather moulding,’ and ‘ water table,’ a projecting tablet or mould¬ ing over the heads of doorways, windows, archways, niches, etc. Driver, the foremost spur in the bulge-ways, the heel of which is 165 DRUMMOND LIGHT. DRI fayed to the foreside of the fore¬ most poppet, and the sides placed to look fore and aft in a ship. Driver, the bent piece of iron fixed in the centre chuck, and projecting over it to meet the carrier, and drive it forward. Driving shaft, any shaft which gives motion to another shaft. Driving springs , the springs fixed upon the boxes of the driving axle of a locomotive engine, to support the weight and to deaden the shocks caused by irregularities in the rails. Driving wheels, the large wheels of a locomotive engine, which are fixed upon the crank-axle or main shaft of the engine. Drop, in architecture, is an ornament of the columns of the Doric order, representing drops or little bells under the triglyphs. Drum, in architecture,thebell-formed part of the Corinthian and Compo¬ site capitals. Drum, a hollow cylinder fixed on a shaft, for driving another shaft by a band. Drummond light, a peculiar light in¬ vented by the late Captain Drum¬ mond, called a heliostat, which re¬ flected the sun’s rays in sufficient abundance to render the station which was to be observed visible. This invention obviated the diffi¬ culty of distinguishing the stations chosen for the angular points of the triangles in a geodesical sur¬ vey : where those stations are many miles asunder, it is necessary to have recourse to illuminations even in daytime. Dry oil, nearly colourless, may he ob¬ tained by combining linseed or nut oil with litharge, and tritura¬ ting them together for a consider¬ able time ; this will produce a yel¬ lowish creamy substance, which being allowed to rest, soon becomes clear; but if there be not time to wait, this fluid may he filtered through blotting paper : it is then transparent, but with a little colour, 166 DUT which soon goes off when exposed to the light. Druxey, timber in a state of decay, i with white spongy veins. Dryness is a term by which artists express the common defect of the early painters in oil, who had but little knowledge of the flowing con- ! tours which so elegantly show the delicate forms of the limbs and the .insertions of the muscles; the flesh in their colouring appearing hard and stiff, instead of expressing a pleasing softness. The draperies of those early painters, and parti¬ cularly of the Germans, concealed the limbs of the figures, without truth or elegance of choice; and even in their best masters, the dra- i peries very frequently either de¬ meaned or encumbered the figures. Dry-rot, a disease affecting timber, and particularly the oak employed for naval purposes. Many contri¬ vances are employed as remedies ! which have recently been patented, and have been successfully applied. I) Dub, to work with the adze. Ductilimeter, an instrument for com¬ paring the ductility of lead, tin, etc. Ductility is that property of bodies which admits of their being drawn out in length, while their diameter is diminished, without any actual ' fracture. Gold, silver, platinum, iron, copper, zinc, tin, lead, nickel, are ductile in the order here given : wire-drawing depends on ductility. Dums (in Cornish), frames of wood like the jambs of a door or the i frame of a window; set in loose ground in adits and places that are ! weak and liable to fall in or tumble i down. Dungeon, a place of incarceration, formerly the principal tower or [ keep of a castle: it was always the strongest and least accessible part of a building. Durbar (Persian), a court or building jl where the sovereign or viceroy 1 gives audience. Dutch Pink, English and Italian, I Pinks, are bright yellow colours) I DYNAMICS. DUT used in distemper and for paper- staining, and other ordinary pur¬ poses. The pigment called ‘ stil,’ or ‘ stil de grain,’ is a similar pre¬ paration, and a very fugitive yel¬ low, the darker kind of which is called Brown Pink. Dutch School of Painting. —This school of art cannot be said to possess the perfections that are to be observed in the Flemish school; their subjects are derived from the tavern, the smith’s shop, and from vulgar amusements of the rudest peasants. The expressions are suf¬ ficiently marked ; but it is the ex¬ pression of passions which debase, instead of ennobling human nature. It must be acknowledged, at the same time, that the Dutch painters have succeeded in several branches of the art. If they have chosen low subjects of imitation, they have represented them with great exact¬ ness ; and truth must always please. If they have not succeeded in most difficult parts of the chiaro-oscuro, they at least excel in the most striking, such as in light confined in a narrow space, night illumi¬ nated by the moon, or by torches, and the light of a smith’s forge. The Dutch understand the grada¬ tions of colours. They have no rivals in landscape painting, con¬ sidered as the faithful represen¬ tation of a particular scene; but i they are far from equalling Titian, Poussin, Claude Lorraine, etc., who have carried to the greatest per¬ fection the ideal landscape; and whose pictures, instead of being the topographical representation of certain places, are the combined result of everything beautiful in imagination or in nature. Eyeing is the art of staining textile substances with permanent co¬ lours. 'tyke, in coal mining, the banks of basalt or whin, by which the coal J strata are frequently divided. dynamics, the science of moving powers, or of the action of forces DYN on solid bodies when the result of that action is motion. GENERAL DEFINITIONS. 1. The mass of a body is the quantity of matter of which it is composed, and is proportional to its weight, or to the force which must be applied to the body to prevent its gravitating to the earth, and which, being greater or less as the mass is greater or less, we regard as a measure of the mass itself. 2. Density is a word by which we indicate the comparative close¬ ness or otherwise of the particles of bodies, and is synonymous with the term specific gravity. Those bodies which have the greatest number of particles, or the great¬ est quantity of matter, in a given magnitude, we call most dense; those which have the least quan¬ tity of matter, least dense. Thus lead is more dense than freestone ; freestone more dense than oak; and oak more dense than cork. 3. The velocity with which a body in motion moves, is measured by the space over which it passes in any given time ; the unit usually assumed being one second. 4. If the body passes over an equal space in each successive unit of time, the body is said to move uniformly, or to have a uniform velocity, and the measure of such velocity is the space actually passed over by the body in each second. 5. If, however, the body passes over a greater space in each suc¬ cessive second than it did in the preceding, then it is said to move with an accelerated velocity : when the differences between the spaces moved over in any tw’o successive seconds is the same, at whatever period of the body’s motion they be taken, or in other words, when the successive spaces form an arith¬ metical progression, the body is said to move with a uniformly ac¬ celerated velocity; but when the spaces passed over in successive 167 DYN EARLY ENGLISH ARCHITECTURE. EAR seconds increase according to any other law, the body is then said to have its velocity variably accele¬ rated. 6. If, on the other hand, the body passes over a smaller space in each successive second than it did in the preceding, then it is said to move with a retarded velocity ; which, if the successive spaces form a decreasing arithmetical series, is said to be uniformly re¬ tarded ; if otherwise, it is said to be variably retarded. 7. The velocity of a body whose motion is variable is expressed at any moment by the space which it would pass over in a second, if its velocity at the moment spoken of were to continue uniform for that period. 8. Mechanical effect is measured by the product of the mass or weiyht of the body into the space over which it has been moved; no Early English Architecture , the first of the pointed or Gothic styles of architecture used in England. It immediately succeeded the Norman towards the end of the 12th cen¬ tury, and gradually merged into the Decorated at the end of the 13th. The mouldings consist of alternate rounds and deeply cut hollows, with small fillets, pro¬ ducing a strong effect of light and shadow. The arches are usually equilateral or lanced - shaped, though drop-arches are frequently met with, and sometimes point¬ ed segmented arches: trefoil and cinquefoil arches are also often used in small openings and panel- ings. The doorways of this style, in large buildings, are often divided into two by a single shaft or small pin, with a quatrefoil or other ornament. The windows are al¬ most universally of long and narrow proportions, and are used singly, or in combinations of two, three, regard being had to the time occu¬ pied. The unit of mechanical effect is a weight of one pound raised through a space of one foot. 9. The momentum of a body in motion means the mechanical effect which such a body will produce in a moment (or second) of time, and varies as the weight of the body multiplied by its velocity. 10. The vis viva of a body in motion is the whole mechanical effect which it will produce in being brought to a state of rest, no regard being had to the time in which the effect is produced, and it varies as the weight of the body multiplied by the square of its velocity. Dynamometer, an instrument which measures anything to which the name of power has been given, whether that of an animal or other¬ wise. Dysodile, a papyraceous brown coal. E. five, and seven: when thus com¬ bined, the space between them ! sometimes but little exceeds the width of the mullions of the latter styles. Groined ceilings are very common in this style. The pillars usually consist of small shafts ar¬ ranged round a larger circular pier, but others of a different kind are sometimes found. The capitals consist of plain mouldings, or are enriched with foliage and sculpture characteristic of the style. Earthwork. The patented excavator, an American invention, is capable, it is said, of cutting and levelling earthwork for the making of rail¬ ways and for other works at a cost! considerably below manual labour,, and has the additional advantage of saving much time: it forms an important consideration in railway making, hut little used in England. Earth-table, the lowest course of stone that is seen in a building, level with the earth. EAS EFFECTS OF BUILDINGS. EFF Easel, for painters, the frame on which the canvas is laid, stretched for painting. East Indian Black-wood grows to an immense size, and is much used for making furniture. Easter, a movable feast held in com¬ memoration of the Resurrection. Being the most important and most ancient in observance, it governs the other movable feasts through¬ out the year. Eaves, the lower edge of a sloping roof which overhangs the face of a wall, for the purpose of throwing off the water. Ebony wood is of several colours, as yellow, red, green, and black. The latter is always preferred, and is much used. It is imported princi¬ pally from the East, and is used for cabinet, mosaic, and turnery work, for flutes, handles of doors, knives, surgeons’ instruments, piano-forte keys, etc. Eborarius, a term applied by the Ro¬ mans to a kind of ivory-work. Eccentric , or Excentric, a circular disc revolving within a strap or ring, and having its axis of revolution on one side of the centre. It is used as a substitute for a crank for giving a reciprocating motion to the slide-valve or to the feed-pump of a steam-engine. Eccentrics are circular sheaves with a hole for the driving-wheel axle, I about two inches out of the centre of i the sheave of a locomotive-engine, which thus makes it project some 1 four inches more from the centre of the driving axle on one side than on the other. It is this eccentricity |j of motion which works the slide- i valve gear and pumps in a very sa¬ tisfactory manner. Eccentrics are fitted in two parts, and secured to | the axle by a hoop and setbolts. Eccentric hoops, hoops fitted round the projecting part of the eccentric sheaves of a locomotive-engine, to strengthen them. Eccentric rod and strap, the rod, the strap end of which encircles the . ---- eccentric sheave, and the other end connects it w T ith the quadrant, or rocking-shaft, according to the class of a locomotive-engine. In some engines the end is forked to go on the stud of the rocking- shaft, and opens out something like the letter V; or when only one rod is used for both back and forward movements, it resembles the letter X. In other engines it is attached to the quadrants by a bolt, one rod for forward gear, and another rod for backward gear. Eccentric rod, the rod connecting the eccentric strap to the lever which moves the slide-valve. Eccentric strap, a brass ring formed by two pieces bolted together, and fixed to the eccentric rod: the ring fits a grooved part in the cir¬ cumference of the eccentric. Echinus, the egg and anchor, or egg and tongue ornament found carved on the ovolo, in classical architec¬ ture. Echinus, a member of the Doric capi¬ tal ; so called from itsjesemblauce to f^e echinus, or large vase, in which drinking-cups were w'ashed. Ecphora, the projection of any mem¬ ber or moulding before the face of the member or moulding next be¬ low it. Eduction pipe, the pipe from the ex¬ haust passage of the cylinder to the condenser. Effect is the art of giving to a draw¬ ing a striking appearance, or so¬ lemnity, awe, sadness, mirth, or tranquillity, by a judicious combi¬ nation of objects, and by strong light and shadow. It is a faithful representation of the appearance of nature, best seen under certain cir¬ cumstances and at certain times, such as morning effect, evening effect, twilight effect, and stormy effect, torch-light and candle-light effects, etc. Effects of buildings. “ The site adapt¬ ed for buildings, and the accompa¬ niments of terraces, gardens, and other decorations to set off their 169 EGG EGYPTIAN ARCHITECTURE. ELA architectural designs, are subjects for consideration in which we are influenced by the desire to raise and extend the theory and practice to what we consider belongs to the art. It was in Italy, when the fine arts were in perfection, that the laying out great villas w'as prac¬ tised by artists who often combined the practice of painting and archi- ture; and until it be adopted in England, the designs of the archi¬ tect never will have justice done to them in the execution. Our parks may be beautiful, our mansions fauliless in design ; but nothing is more rare than to see the two pro¬ perly connected. Let the architect by study and observation qualify himself to include in his art the decorations around the immediate site of the intended building, toge¬ ther with its interior adornment, furniture, and upholstery, and the growing taste among the gentry of England will second such laudable efforts.” Egg, in architecture, an ornament of that form, cut in the echinus or quarter round. Egyptian Architecture had its origin 2222 years before Christ, and ad¬ vanced and flourished under dif¬ ferent dynasties. The first includes the two great dynasties of Theban princes, who governed Egypt dur¬ ing her “ most high and palmy state,” when Thebes sent forth her armies to distant conquest. In the second period is comprised the erection of the Pyramids. The third includes the reigns of the Ptolemies and earlier Caesars, un¬ der whom Egyptian architecture flourished in a second youth, and almost attained its original splen¬ dour, Egyptian architecture, so massive anil so sombre, with its vast aisled halls without windows, its close files of gigantic columns, and its colossal statues, owes many characteristic forms and elfects to earlier cavern temples in Ethiopia. One of the most striking peculiari- 170 ties of the style is the pyramidal character of the ascending lines: I it is observed in the outline of the . portal and the gigantic pylon, in walls, doorways, pedestals, and screens: it pervades the whole t system, and must have been occa- ‘ sioned by circumstances connected with its origin. The representa- ! tions given in ancient paintings show a remarkable love of unifor¬ mity of arrangement of their do- i mestic houses and gardens. In an ordinary house a number of cham- | bers were ranged round a rectan- Ij gular court, as at Pompeii. The || larger mansions sometimes consist- ji ed of an assemblage of such courts, | the whole occupying a square or oblong plot. Sometimes a central group of buildings was surrounded ; by a narrow court. A spacious area often extended from front to rear, j with a chief and side entrances at I either end: the exterior had no- ! thing of the ponderous character of temple structures, which would have been ill-suited to the wants and festivities of social life. Houses two and three stories high were common; hut large mansions ap¬ pear to have been low and extensive rather than lofty. The terraced top was covered by an awning or roof, supported on light graceful columns. | Ediograph, an instrument contrived forthe purpose of copying drawings. Ekeing, in ship-building, a piece fitted to make good a deficiency in length on the lower part of the supporter under the cat-head, etc.; likewise the piece of carved work under the lower end of the quarter-piece at the aft part of the quarter-gallery. Elastic, springy, having the power of returning to the form from which it w r as distorted. Elastic force of steam. The French reckon an atmosphere to be equal to a column of mercury ‘76 of a metre in height, which is onlyi 29'92 inches, and the boiling point of their thermometer is adapted; thereto; whereas, since about the! ELECTRICITY. ELB ELECT KICITY. ELE commencement of the pressnt cen¬ tury, the English have reckoned it to be 30 inches. This circum¬ stance accounts in some degree for their scale of temperatures differing from Mr. Southern’s. The French account of the occa¬ sion of making their experiments on the temperatures corresponding to different elasticities of steam, in 1829, contains the following pas¬ sage : ‘ Science did not then pos¬ sess this knowledge, and engineers appointed to superintend the con¬ struction of steam-engines had no other guidance than some discord¬ ant measures upon the tempera¬ tures which correspond to the elas¬ ticities between one and eight at¬ mospheres : for higher pressures there was no result of direct expe¬ riments, nor any theory which could supply the deficiency.’ Elbow, in architecture, an obtuse angle of a wall, building, etc. The term Elbow is also used to denote the upright sides which flank any panelled work, as in windows helow the shutters, etc. Elder-wood.. The branches of the elder contain a very light kind of pith, which is used, when dried, for electrical purposes; the wood is also frequently used for carpenters’ rules, weavers’ shuttles, etc. Elective Affinity , preference of one chemical substance for another. Electrical state of the atmosphere. The electrical condition of the air in serene and tempestuous weather has been too much overlooked by meteorologists. The atmosphere is generally found to be in an elec¬ trical state. The apparatus for these observations is simply a me¬ tallic rod, insulated at its lower extremity, elevated at some height above the ground, and communi¬ cating with an electroscope. When the amenity of the weather will permit, a kite should be raised, in the string of which a metallic wire should be interwoven ; this will collect the electricity of the higher regions of the air. Theatmosphere is usually found to be positively elec¬ trified, and its electricity is stronger in the winter than in the summer, and during theday than in thenight. Electricity, the name of which is de¬ rived from the Greek word ? )\ac- rpov, amber, because it was in friction of this substance that the subtile and invisible agency which we designate electric fluid was first discovered, is one of those hidden and mysterious powers of nature which has thus become known to us through the medium of effects: our first acquaintance with it appears to have arisen out of a curious but simple fact, noticed full 600 years before the Christian era. Thales, of Miletus, a celebrated Greek phi¬ losopher, the founder of the Ionic Philosophy, observed, as a remark¬ able property of amber, its power of attracting light particles of matter on being subjected to a peculiar kind of excitation by fric¬ tion, and with which he is said to have been so struck, that he imagined the amber to be endowed with a species of animation. Theophrastus, about 300 years before the Christian era, observed a similar property in a hard stone termed the lyncurium, now sup¬ posed to have been the tourmaline, which he says will not only attract light straw's and sticks, but even thin pieces of metal. Pliny and other naturalists also notice this property of amber ; and a similar property is said to have been dis¬ covered at an early period in agate. In the present state, however, of this department of science, we no longer confine our views to a par¬ ticular instance of electrical action limited to a few conditions only, but consider the development of electricity as arising out of a great variety of operations and circum¬ stances, both natural and artificial -—such as the contact of various substances, friction, pressure, cleav¬ age, and other mechanical pro- i 2 171 ELE ELECTRICITY. ^-cesses, changes of temperature and form, as in tiie case of liquefaction, and other natural processes of that kind, together with chemical and certain forms of magnetic action ; these will all superinduce upon bodies an attractive power of a greater or less amount. As our knowledge of such phenomena advanced, these other substances, possessing similar properties, were considered as being amber-like, were said to be electrical, and were hence termed Electrics. In a similar way, when any given substance was caused to exhibit attractive powers by the simple process of friction, it was said to be electrified ,—the process itself being termed electrical excitation, and the attractive force electrical attraction : any contrivance also for the mere exhibition of such force has been termed an Electro¬ scope, whilst other contrivances for the more precise measurement of the power itself have been termed Electrometers; so that the common terms employed in this department of science are all based on the Greek and Latin terms signifying amber. This scienceissometimes divided into five or six branches, according to the modes in which electric effects may be brought about. The term atmospheric electricity applies to that which is naturally exhibited at nearly all times, but especially in thunderstorms ; common or frictional electricity, to that deve¬ loped by mere mechanical actions ; galvanism, or voltaic electricity 7 ’, to that developed by chemical action; t/(e/7Mo-electri('ity, by the action of heat; magneto-electricity, by that of magnetism ; and animal electri¬ city, by the will of certain fishes, which use this power as a defence. A more modern and comprehensive division is into—1 . Electro-statics, or tensional electricity, referring to those effects in which the agency seems to have the equilibrium of its distribution disturbed, so as to 172 ELE be excessive or deficient in certain bodies, making them appear in dif¬ ferent states. 2. Electro-dynamics, or current electricity, describing those effects in which the agency appears to he moving from place to place, and displaying momentum. It is convenient to denominate this peculiar agency Electric fluid, because it has a greater resem¬ blance to an elastic fluid of extreme rarity than to anything else with which we are acquainted. Some bodies permit this agency to pass freely through them, and are hence called conductors; others hardly permit it to pass through them at all, and are therefore known as non-conductors. Metals are the best conductors ; next water and fluids ; then the bodies of animals. Glass, resinous substances, such as amber, varnish, sealing-wax, silk, wool, cotton, hair, and fea¬ thers, are non-conductors. The h phenomena of electricity are such as j attraction and repulsion, heat and light, shocks of the animal system, and mechanical violence. The word Electricity is also used to* }u denote the science which treats of this peculiar and invisible agency. For a knowledge of the pheno- j i mena themselves, consult the treatises on ‘ Electricity, Magnet¬ ism, and Galvanism,’ by Sir W. Snow Harris, in the Weale Series, j Electric, a non-conductor of electri¬ city employed to excite or accu- j mulate the electric fluid, for which purpose amber, glass, resin, wax, gum-lac, sulphur, etc., arc usually made use of. Electric Light. In the Supplement to Mr. Tomlinson’s ‘ Cyclopaedia of Useful Arts ’ the following in¬ teresting account is given of the . Electric Light;—‘When the cur¬ rent of a powerful voltaic battery is closed by means of two pencils of hard charcoal, which is an imper- I feet conductor, the points become ! incandescent, and produce a light J which has hitherto been unsur- j ELE passed in brilliancy. Charcoal is infusible, so that it will bear the enormous heat produced ; the best form of charcoal is that which is sometimesdeposited within the gas retort employed in the manufac¬ ture of street-gas. The form of the flame is not symmetrical with respect to the two poles of the battery, the part next the positive pole having the greatest diameter ; and the diameter gradually de¬ creases in approaching the negative pole. The light is not true com¬ bustion, as is proved by the fact that no carbonic acid is evolved, and also that the light is even more intense in a vacuum ; it may also be produced in gases which do not support combustion. There is, however, a mechanical trans¬ port of the material of the charcoal points. If these be sharp at the commencement of the experiment, the piece attached to the positive wdre will have its point worn down into a cavity. At the same time, a mammillated deposit con¬ tinues to grow upon the charcoal of the negative wire. When the battery is very powerful, the elec¬ tricity between the two charcoal points assumes the form of an arc of dazzling brilliancy. With 600 of Bunsen's cells arranged con¬ secutively, with the points in a vertical line, and the negative pole below,Despretzobtained an arc 7 - 8 inches in length. With 100 pairs the arc was only one inch in length. The most intense light is obtained when the points are very near together, since, in such case, the resistance is less, a greater quantity of electricity passes in a given time, and the temperature is pro¬ portionally higher. The arrange¬ ment of the cells is also of im¬ portance. Despretz obtained a much more intense light when his 600 cells were arranged in six parallel series, the effect being that of 100 cells of six times the size, as compared with the arrangement ELE of a consecutive series of 600 cells. He also found that when the char¬ coal points were arranged horizon¬ tally at right angles to the mag¬ netic meridian, the length of the arc with 200 pairs of Bunsen’s cells, in two parallel series, was greater in the proportion of 20’8 to 16'5, when the positive pole was to the east, than when it was to the west. Messrs. Fizeau and Foucault have instituted a com¬ parison of the electric light with that of the sun, by means of the chemical effects produced on iodide of silver. Taking the intensity of the solar light at mid-day at 1000, the electric light from 46 pairs of Bunsen was represented by 235, while with 80 pairs it was only 238. The electric light exerts some of the effects of solar light; it determines the combination of a mixture of chlorine and hydrogen, and blackens chloride of silver. When passed through a prism, the resulting spectrum varies with the material of which the electrodes are made. Many attempts have been made to introduce this bril¬ liant light into use for the purposes of artificial illumination, and most of our readers will have seen it during nightwork for engineering purposes, street illuminations, and also in the lecture-room, for the illustration of optical and other experiments, for which it is ad¬ mirably adapted. It is also used in the theatre, where some brilliant and beautiful stage effects are pro¬ duced by its means. The objec¬ tions to the use of this light are— first, its cost, which is consider¬ able; secondly, the intensity of the light, which is painful to the eyes; thirdly, the mechanical arrange¬ ment, which involves some prac¬ tical difficulties : the transfer of conducting matter from one pole to the other is also an objection. This light was used at Cherbourg by night, during the excavation of the docks : two sets of apparatus ELECTRIC LIGHT. 173 ELECTRIC LIGHT. ELE were employed, each maintained with one of Bunsen’s large bat¬ teries of 50 pairs, at a cost, it is said, of not more than 14 francs 55 cents for each apparatus. The two gave sufficient light for 800 workmen. The first philosopher who applied the electric light as a substitute for the lime-light in the gas miscroscope was, we believe, M. Foucault. Now, one of the great practical difficulties in the employment of this light is to keep the points at a uniform dis¬ tance from each other, and at the same height in the lantern, so that the source of light may always be in the same position with respect ELE to the lens. This is effected by means of an electro-magnet and a clock movement, the function of the latter being to bring the two points towards each other, so as to compensate for their waste in burning, while the electro-magnet checks the clock action when it is no longer required. It is found that the negative point is always consumed in the air more slowly than the positive one, so that means have to be provided for moving each point proportioned to the rapidity of its waste; this effect is produced by making the two cylinders of unequal dimen¬ sions, while the chains transmit DELEUIi’S PHOTO-ELECTRIC APPARATUS. the movement of the clockwork to the points. The barrel con¬ tains a mainspring, and the clock movement, which is moderated by a fly, tends to bring the two char¬ coal points nearer together. This is done by means of two chains, one of which is wound on the small barrel and guided hv the small pulley, passes up the tube, over the pulleys, and is finally attached to the metal holder, which holds the negative charcoal point. The other chain is wound upon the large drum, which moves on the same axis as the small drum. This chain is guided over the pulley, and passing down the tube which holds the charcoal point, is fixed at the bottom of the tube. M. Deleuil has a photo-electric ap¬ paratus, in which the self-acting adjustment is very simple. The negative charcoal pencil is sup¬ ported by a metallic rod, sliding with friction in a support, but being ottce regulated, it remains fixed. The positive pole is raised by the current as the charcoal is wasted. For this purpose, a lever, A (see cut), attached at one end to a spiral spring, B, is capable of oscillating on the pivot L, through a very small space, and is main¬ tained at the other end between the points of two screws, which limit its play. This lever is drawn upwards by the spring B, and 174 ELM ELE ELECTRIC. downwards by the electro-magnet E. At the end of the lever, near B, is a straight steel spring, the upper end of which, at I, is en¬ gaged in the teeth of a ratchet- bar, on the rod which carries the positive charcoal pencil P, and transmits to it the motion of the lever. As long as the current passes with its full force, the electro-magnet, E, attracts its armature, m, which is attached to the lever A, one arm of the lever rises, and the opposite arm sinks, the spring is drawn down, so that its upper extremity is lowered from one tooth to another .of the rack. When, however, the distance be¬ tween the charcoal points is in¬ creased the current becomes weaker, and the electro-magnet, not being able to support the arm of the lever, the end is drawn up by the spiral spring, and the small spring being pressed against the tooth of the wheel, drives it upwards and raises the pencil, whereby the points are brought together again, and the current is re-established. At C is a screw for regulating the spiral spring B. O is a section of the iron table that supports the apparatus. The arrow shows the wires that convey the current.’ Electric Telegraph. To enter at length in this place into the history and construction of the Electric Telegraph would somewhat in¬ terfere with the plan of the present work ; but as the subject is one of great and absorbing interest, by way of Appendix at the close of the alphabet, at page 585, the reader will find it lully discussed, and illustrated with numerous dia¬ grams, showing the construction and working of the instrument. ‘The Electric Telegraph’ requires, and has found, an exhaustive trea¬ tise in the elaborately illustrated volume recently published by Mr. Robert Sabine, of which it is in¬ tended to give in the Weale Series an abridged edition. On that account nothing is said of the con¬ struction of Submarine Telegraphs in the Appendix just referred to, because the principles which go¬ vern the overland telegraph are the same as those which apply to submarine telegraphy. Electrode, the pole of the voltaic circle. The electrodes are the surfaces of air, water, metal, etc., which serve to convey an electric current into and from the liquid to be decomposed. Electrometer, or Electroscope, an in¬ strument for measuring the quan¬ tity, pressure, or intensity of elec¬ tricity. Electrum, from the Greek, a name given to amber, or to a mixture of metals composed of gold and silver. Electrum, argentiferous gold; an alloy of silver. Elegance, in a design, is a manner which embellishes and heightens objects, either as to their form or colour, or both, without destroying or perverting truth. Elevation, an upright draft of a build¬ ing, geometrically drawn. Elizabethan Architecture, the style which prevailed in England at the time of Queen Elizabeth, and im¬ mediately subsequent to the Tudor style of Henry VIII. Ellipse : this curve is one of the conic sections, and next in importance to the circle and the straight line. Ellipsis, an oval figure generated from the section of a cone by a plane cutting both sides of the cone, but not parallel to the base, and meet¬ ing with the base when produced. Elliptic compasses, a term given to any machine for describing ellipses. Elliptoyraph, an instrument for draw¬ ing ellipses. Elm, a timber-tree, of European growth, and of which there are five species: mean size, 44 feet long, • 32 inches diameter : it is not liable to split, and bears the driving of nails, bolts, etc. : much used in building; also for the keels of ves¬ sels, and for wet foundations. ELO ELECTRIC TELEGRAPH. EMB Elutriation, the separation of foul substances from pure by pulveriza¬ tion. Elutriation, in metallurgy, the sepa¬ rating the lighter matters from the mixed ores or metals, by means of great quantities of fair water. Elvan (in Cornish), a hard close- grained stone, said to be a bastard limestone. Embankments, raised mounds or dykes to preserve the proper and useful course of rivers, etc.; and also for forming a level line of railway. Embankments (some) executed on the Continent. On the banks of the Po, two sorts of dykes are used to prevent the river from overflowing during the winter, or the flood season. They are called ‘ in froldi ’ when immediately upon the banks of the river, and ‘ in golene ’ when at any considerable distance, as it is sometimes found advisable to allow the river to spread over a large surface of the adjacent valley, either for the purpose of admitting it to deposit the mud in suspension, or to allow it to lose its torrential character. The maintenance of the works of these dykes is con¬ fided to the Government engineers, who are under the control of a syndicate of the proprietors of the property most liable to be affected by inundations. On this subject consult Professor Paul Frisi’s ad¬ mirable treatise on Rivers and Torrents, in the Weale Series. The Haarlem lake, besides the very remarkable steam-engines de¬ scribed by Mr. Dempsey, merits observation for the extensive works executed for the defence of the land, and for the canals reserved for the navigation. The enclosure dyke is 50,000 metres long, or rather more than 31 miles. It has two outfall dykes, which serve for the navigation, 9,000 metres, about 5£ miles ; one half of which is 40 m - (131 ft. 2 in.) wide at the bottom or floor line; the other 43 m - 20 (141 ft. 10 in.) The ordinary tides are, at the flux, 2 ft. 4 in. above the scale or datum line at Amsterdam ; at the reflux, 2 ft. 8 in. below the same datura: the difference between high and low water is then, on the average, about 5 feet. With vio¬ lent winds from the n.w. however, the tides rise sometimes 6 ft. 6 in. above the average. The tides of the Y, near the lake, are 4- 16°- (or 64 in.) and — 23 c - (or 9 in.), giving a total variation of 1 ft. 3§ in. The estimated cost of reclaiming the 18,000 hectares was 8 millions of florins, or £667,000 English, nearly, about £13 per acre. Pre¬ viously to undertaking this colos¬ sal work, the Zind Plass, of 4,600 hectares superficial (nearly 11,500 acres), had been reclaimed at a cost of 3 millions of florins, or £250,000; not far from £22 per acre. The heights of the enclosure dyke are -I- or — the datum line or mean level of the sea at Amsterdam. Embankment of the flooded part of the Amsterdam and Haarlem Rail¬ way. The bottom part consists of treble ranges of fascines, tied down by longitudinal poles 1 metre apart from centre to centre, and 0'25°- diameter; two double stakes at each end of the poles, and two ties in the intermediate distances. The interstices of the fascines and the space between the rows are filled in with sand. The upper part, forming the encasement for the ballast, is made of three rows of treble fascines, well staked, and wattled together. A core of sand or clay, faced with step fascines, is made up to low- water mark. Upon this a bed of rushes, fastened down by stakes and wattles, is laid ; and the upper portion of the bank is faced with fascines of a regular slope of 1 to 1. Embattled, a term applied to any building with a parapet, and having embrasures to resemble a battery. Emblema, an emblem, or inlaid orna¬ ment of divers colours. 176 EMB ENGINEERING. ENG Embolus , in mechanics, a wedge; an¬ ciently, among the Greeks,the prow or beak of a vessel, or a body of soldiers in the form of a wedge. Embolus, the movable part of a pump or syringe, named likewise the pis¬ ton or sucker. Embossing , forming work in relievo, whether cast or cut with a chisel; or in modern times, the art of pro¬ ducing raised figures upon wood or other materials by means of pres¬ sure, either applied by a sudden blow, as in a stamping press, or in a more gradual manner, as by an ordinary screw or hydraulic press, or by means of revolving cylinders. Embrasure, the crenelles or interval between the merlons of a battle¬ ment. Embroidery , a mode of working de¬ vices on woven substances. Emerald green is a new colour of cop¬ per green upon a terrene base: it is the most vivid of this tribe of colours, being rather opaque, and powerfully reflective of light: it appears to be the most durable pigment of its class. Emissarium, a sluice, flood-gate, or channel by which an outlet is formed to carry off stagnant'or foul water: according to Pliny, an arti¬ ficial canal, formed for the draining of stagnant waters. Emplecton, a method of constructing walls introduced by the Greeks and copied by the Roman architects, in which the outside surfaces on both sides were formed of ashlar laid in regular courses, and the central space between them filled in with rubble-work, layers of cross stones being placed at intervals in regular courses, and of sufficient size to ex¬ tend through the entire thickness of the wall, and so act as girders to bind the whole together. Emporium, a mart or factory, a large building containing ranges of bond¬ ing warehouses, in which foreign merchandise brought by sea is de¬ posited for sale. Enamelling, the art of using enamel, which is divided into trasparent and opaque. The first is employed for the purpose of ornamenting gold and silver; the second, commonly in the manufacture of watch and clock dials, and of plates for pic¬ tures, etc. Encarpa (Encarpus ), according to Vitruvius, festoons of carved fruit and flowers, employed as decorative ornaments. Encaustica, the art of encaustic painting, i.e. in colours mixed with wax, and afterwards hardened by the action of fire. Encaustic painting, a kind of paint¬ ing in which by heating or burning in, the colours are rendered perma¬ nent in all their original splendour. Enchasing, the art of enriching and beautifying gold, silver, and other metal work, by some design or figure represented thereon in basso rilievo. Enclosure, a fence, a wall, or hedge, or other means of protection and security surrounding land. Endecagon, in geometry, a plane fi¬ gure of eleven sides and angles. End-irons, andirons or dogs, articles of household furniture, in earlier times, used in fire-places to sustain the ends of logs of wood. Engineering, Civil. This profession may be said to have originated in England about the middle of the last century. Before that period, whenever the prospects of great profit induced individuals or bodies to incorporate themselves for the purpose of undertaking extensive systems of drainage, or for the supply of water, requiring the as¬ sistance of an engineer, recourse was generally had to those great masters of hydraulic engineering, the Dutch. True it is that some so¬ litary exceptions have occasionally been found; men who, like Sir Hugh Myddelton, combined a spe¬ culative turn of mind with some mechanical knowledge, and to these two qualities added an un¬ tiring energy of purpose, leading 177 13 ENGINEERING. ENG ENG them to persevere in any under, taking, even under the most dis¬ couraging circumstances. But these men were rare instances of a peculiar talent, which, though it thus displayed itself occasionally, was far too uncommon a gift to allow the possessors of it to form a class or profession. The case is very different now: a demand for this peculiar talent has been created of late years by the extraordinary development of our system of in¬ ternal communication, as well as by the application of steam to the purposes of our manufactures; i and employment is now found for hundreds where one was sufficient, not fifty years since, for the whole business of the country. So great indeed has been the demand, that the profession may be said to be divided into two distinct bodies, viz. those who turn their attention to subjects which come more par¬ ticularly within the scope of the duty of a civil engineer, such as docks, bridges, canals, railroads, etc., and those who devote them¬ selves altogether to the manufac¬ ture of machinery. The duties which are involved in the practice of these two branches of the pro¬ fession, though apparently dissimi¬ lar in character, are yet founded upon the same general principles ; and the acquirements which are necessary to enable the individual of one class to distinguish himself, or even to practise his profession with a moderate chance of success, will be found equally necessary for those of the other class. These acquirements are partly abstract and theoretical, and partly experimental or practical. A civil engineer should, in addition to the knowledge required to fit him as well as others for the active duties of life, have such a knowledge of mathematics as will enable him to investigate as well as to apply the rules laid down by writers on those branches of the mixed sciences to which his attention will most fre¬ quently be drawn. He should be well acquainted with the principles of mechanics, hydraulics, and in¬ deed with all the branches of na¬ tural philosophy; and a certain amount of chemical knowledge will be found very valuable: he should be able to draw neatly, and should understand the principles of pro¬ jection upon which all engineering drawings are constructed : a gene- ral knowledge of the principles of architecture will also be essential. Having acquired the requisite a- mount of theoretical information, the next step is to gain that prac¬ tical knowledge which is essential in order to the proper application of this information. The best mode of gaining this experience is to enter into the employment of some eminent man in the profes¬ sion, in whose office there will be every opportunity offered to the young beginner of witnessing the mode in which the various descrip¬ tions of work are carried on. He will there be employed, first as a draughtsman, in copying drawings: I as he becomes more acquainted with practical details, he will have more responsibility thrown upon him, and be placed in charge of works, at first of small importance, but, by degrees, of those of such magnitude as will require all his theoretical knowledge, and all the practical experience he may have gained, to enable him to carry out the work to the satisfaction of his employers: he should cultivate a | habit of observation, and make a : point of taking ample notes and ! sketches of whatever he may see I which in any way bears upon his profession. Having thus by de¬ grees acquired a sufficient amount of information to give him a con¬ fidence in his own judgment upon any subject which may be submit¬ ted to him, and having become known as an active and intelligent agent of others, he will very pos- ENG ENGINEER. ENG sibly be called upon to plan and execute a work himself, and then, by degrees, with industry and ac¬ tivity, may work his way upwards in a profession where merit alone can lead to distinction. The course of the man who de¬ votes himself to the machinery branch of the profession differs but little, up to a certain point, from that just described : his theoretical acquirements should be the same, but the practical part of his edu¬ cation will commence at the bench, where he will learn the use of all the tools and machinery by working at them with his own hands : he will then be placed in the drawing room, and go through much the same routine of instruction as be¬ fore described, and will by degrees work his way up to the position of foreman; then, distinguishing himself by a power of applying general principles to particular cases, he will show himself capable of assuming the direction of an establishment for the manufacture of machinery. Engineer , Steam-boat. A steam-boat engineer is a person employed for the purpose of keeping the engine or engines of a steam-vessel in as efficient a state as possible, and to superintend their working. He must set the engines to work, regulate their speed, and stop them, as may be required. His duties while the engines are at work are various. He must take care that every moving part is properly lu¬ bricated ; that no steam is allowed to pass through valves or joints that ought to be steam-tight; that no air is permitted to enter in any of the parts of the engine where it is essential that a vacuum should be kept up ; and that none of the bolts, or pins, or keys, work loose by the vibration, and shift their position, or come out of their places. He must also take care that none of the working parts be¬ come overheated by any undue amount of friction, arising from any want of proper lubrication, any excessive tightness, or any other disturbing cause ; and if they should become overheated, he must take prompt and energetic measures to remedy the evil, and prevent any serious consequences arising therefrom. He must from time to time carefully observe the effect produced by the gradual wear of the working parts, so that if the truth or accuracy of any of these seems to be materially affected, he may take steps to rectify the defects when lying up in harbour. He must also be careful to observe if the frame of the engine ever begins to move or work in any way, and en¬ deavour to discover the cause, in order that it may be remedied when the engines are at rest. One of the most important of bis duties is to take care that the engines are kept clean, and any grit or dirt prevented from getting into the bearings or moving parts : he must wipe away all oil and grease most carefully and completely as soon as they have passed through the bearings, and prevent them from running down the rods or remaining about the engine. The boiler requires his unremit¬ ting and particular attention, in order that the proper supply of steam, neither too much nor too little, may be generated for the en¬ gine. To ensure this, the manage¬ ment of the flies must be duly attended to, both in the supply of coal in the proper quantities at the proper intervals, and in the perio¬ dical clearing of the fires from the earthy matters of the coal, which may have become vitrified in the furnace, and formed what are call¬ ed clinkers. By due attention to the former, the smoke in all well- proportioned boilers may be very greatly abated; and, by due at¬ tention to both, the consumption of fuel (when the engines are pre¬ vented by a strong head-wind, or 179 ENG ENGINEER. ENG by the deep immersion of the paddle-wheels on the commence¬ ment of a long voyage, from making the proper number of strokes, and thus using the proper amount of steam) may be reduced in an equal or greater degree than has taken place in the consumption of steam. The due and constant supply of water to the boiler, to compensate for the constant evaporation of the water in the formation of the steam, must he assiduously attended to. Another of the most important of the duties of a steam-boat engineer, during the time that the engines are at work on a voyage at sea, is to attend to the degree to which the water in the boilers may be¬ come saturated with salt by thecon- tinued evaporation which is going on, and to take care that this satu¬ ration is not allowed to be carried to such an extent as that a deposi¬ tion of the salt and other matters contained in sea-water should take place. After the boilers have been in operation for three or four hours in salt water, so that the water in them has become brine, he ought to test the strength of it, that is, he ought to ascertain the degree of sa¬ turation to which it has reached, and continue this examination pe¬ riodically, whether the engines are fitted with an apparatus for the con¬ tinuous discharge of a portion of the brine, to be exchanged for a portion of sea-water, or whether this system of exchange is left en¬ tirely at his discretion, to be at¬ tended to by means of the common blow-off cocks. The best test is the common hydrometer, though the thermometer has hitherto been more commonly applied to this pur¬ pose, as the brine is considered to be of a proper strength when it boils under atmospheric pressure at a temperature 2° higher than that at which the common sea-water will boil at the same time, under the same circumstances. Before coming into port, it may occasionally be advantageous to take indicator diagrams, to see whether the action of the valves continues to be correct. The duties of a steam-boat en¬ gineer, on arriving in port after a long voyage, are also various, and equally important with those he has to perform when out at sea. Im¬ mediately on coming to anchor, it is a good practice to test the tight¬ ness of the steam-valves and pis¬ tons, by putting them in such a position that it can be seen if they allow any steam to pass when it ought not to do so. If any im¬ perfections in these the most vital parts of the engines are discovered, he must draw out the valves, or lift the cylinder covers, to get at the pistons, and rectify the defects in the best manner that he can with the means within his power. He should also occasionally examine all the interior parts of the engines, and rectify any incipient defects. He must now also rectify any want of truth in the parallel motion or in any of the shafts or working parts caused hv wear, and tighten or make good any of the fastenings of the frame if he has found them to be loose, and put to rights any other such defects. Any parts sub¬ ject to corrosion should be carefully examined, cleaned, and dried, and painted if need be. The water should be blown off out of the boilers as completely as possible, and all ashes and soot thoroughly cleaned out of the furnaces and flues as soon as possible. The fur¬ naces and flues must then be tho¬ roughly examined, and the slight¬ est leak or defect that can be discovered made good; as it is especially important in a boiler to stop these defects at the first, as otherwise they spread very rapidly. No pains should be spared to dis¬ cover any suspected leak of steam on the top of the boiler, as nothing tends more to corrode and destroy a boiler than this. Inside the boil- 180 ENG ENGLISH SCHOOL OF PAINTING. ENG ers, any scale that may have been deposited from the brine having been allowed to become too strong must be removed, and the whole thoroughly cleaned out from every part of the boiler, from below as well as from the tops and sides of the furnaces and flues. The take- up, the inside of the steam-chests, and of the roofs of the boilers, which are the parts most subject to corrosion from the interior, should be very carefully examined, and after being duly scraped andcleaned and dried, they should be well painted with two or three coats of red lead, or done over with some other preservative. The paddle-wheels should also be thoroughly examined, and any I broken floats or hook-boltsreplaced by new ones. The whole of the ironwork should be thoroughly scraped and cleaned, and, when dry, painted with three coats of red lead, or done over with black varnish, once every four months at least. When in harbour, espe¬ cially if lying in a stream or tide- wav, the wheels ought to be turned round every three or four days, to change the parts exposed to the action of the water, and thus pre¬ vent corrosion. The various kinds of the screw now in use should be well studied, and all circumstances connected with its operations [ should be closely watched for every incident or change should be con¬ sidered as a new experiment. He must now also get his supply of stores made good, so as to be ready for another voyage. To qualify an engineer to per¬ form these duties, he should be trained as a mechanic, and be a fair workman in iron, brass, and wood. He shoidd be able to work rot only at the lathe or vice, but also at a smith’s forge. His education should be such as to make him able to keep accounts, and make notes in his log of all that occurs in the engine- room. He should have sufficient knowledge of mechanical drawing to enable him, in the event of any important part of the engines being broken wheu at a distance from any manufactory, to make sucb a draw¬ ing of it as would enable a manu¬ facturer to replace it. He should have some knowledge of the first principles of mechanics, a general knowledge of the leading principles of hydrostatics, hydraulics, and pneumatics, without which he can¬ not fully understand many of the principles carried on in the engine, and on which its power depends. Some knowledge of heat, of the theory of combustion, of ebullition, and of evaporation, may also be reckoned as almost indispensable : to which should be added, if pos¬ sible, an acquaintance with the sub¬ ject of steam, especially as regards its temperature, pressure, and latent heat. Engineer, Mechanical, one who is effi¬ cient in the invention, contrivance, putting together, and the adjust¬ ment of all kinds of machinery ; who is acquainted with the strength and quality of the material used, and who also possesses a thorough knowledge of the power of steam and the engine in all its modifica¬ tions, and the uses for which this motive power is applied : he should also be duly acquainted with mill- work of the several kinds, whether impelled by steam, water, or wind. English School of Painting. This school, which is but of recent date, is connected with the Royal Acade¬ my in London, instituted in 1766 ; and although as a school it did not exist before that period, yet since the revival of the arts, and the con¬ sequent encouragement given to them by the sovereigns of Europe, England has possessed portrait- painters of no inconsiderable abi¬ lity ; and it is probably owing to the remarkable partiality of the na¬ tion for this branch of the art, that historical painting has been, until recently, comparatively neglected. 181 ENG ENTABLATURE. EPI Latterly, however, painters of the highest eminence in this superior branch of the art have distinguished themselves, and given earnest of the rise of a school that may, ere long, surpass others of the pre¬ sent age. English Varnish. When mastic var¬ nish is mixed w'ith drying-oil which holds litharge in solution, the mix¬ ture soon assumes the appearance of a firm jelly; which is strong in proportion as a greater quantity of litharge, and a stronger varnish, have been used. This substance holds its place on the palette. This mixture is particularly useful in glazing, for it flows freely under the brush. Instead of using brown drying-oil, it is preferable to use that prepared without fire. Entablature , those members of a por¬ tico which were constructed upon the columns, consisting of theepi- stylium, zophorus, and corona. Vi¬ truvius uses the words ornamenta columnarum to signify these mem¬ bers ; and sometimes he includes the three several parts in the term epistylia. Entablature, the superstructure that lies horizontally upon the columns in the several orders or styles of architecture. It is divided into architrave, the part immediately above the column ; frieze, the cen¬ tral space; and cornice, the upper projecting mouldings. Each of the orders has its appropriate entabla¬ ture, of which both the general height and the subdivisions are re¬ gulated by a scale of proportion derived from the diameter of the column. The entablature, though archi¬ tects frequently vary from the pro¬ portions here specified, may, as a general rule, be set up one-fourth the height of the column. The to¬ tal height thereof thus obtained is in all the orders, except the Doric, divided into ten parts, three of which are given to the architrave, three to the frieze, and four to the cornice. But in the Doric order the whole height should be divided into eight parts, and two given to the architrave, three to the frieze, and three to the cornice. The mouldings which form the detail of these leading features are best learned by reference to representa¬ tions of the orders at large. Pal¬ ladio and Vignola, the restorers of genuine architecture, are the au¬ thors whose works may be con¬ sulted w'ith greatest advantage by those who desire to make any ad¬ vance in the science, and most par¬ ticularly by those who wish to ob¬ tain further knowledge on the use and abuse of its details. Entail, a term used in the middle ages to signify elaborated sculp¬ tured ornaments and carvings. Entasis, the swell of the shaft or co¬ lumns of either of the orders of ar¬ chitecture. Enterclose, a passage between two rooms in a house, or that leading from the door to the hall. Entresol, in architecture, a floor be¬ tween two other floors. The en¬ tresol consists of a low apartment usually placed above the first floor: in London, frequently between the ground floor and the first floor. Ephebeum, an apartment in the pa¬ laestra appropriated to wrestling and other athletic exercises. Epicycle, a little circle whose cen¬ tre is in the circumference of a greater. Epicycloid, a curve generated by the revolution of the periphery of a circle along the convex or concave part of another circle. Epicycloidal wheel, a wheel for con¬ verting circular into alternate mo¬ tion, or alternate into circular. Episcenium, a division of the scene of a Greek theatre : it sometimes con¬ sisted of three divisions made by ranges of columns one above the other : the lower was termed scena, and the others episcenia. Epistomium, the cock or spout of a water-pipe, or of any vessel contain- 182 EPI ERA. EVA ing liquids to be drawn off in small quantities when required. Epistylium, the lower of three divi¬ sions of an entablature or super¬ structure upon the columns of a portico, formed by pieces extend¬ ing from centre to centre of two columns. Epistylium, the architrave or hori¬ zontal course resting immediately upon columns. Epistylar arcua- tion is the system in which co¬ lumns support arches instead of horizontal architraves and entab¬ latures. Epitithidas, a term applied by some writers, by way of distinction, to the cymatium on the sloping or raking cornices of a pediment, which superimposed moulding (as its name implies) was frequently largely developed, and enriched with an ornamental pattern. Epitithides, the upper members of the corona surmounting the fastigium of a temple, which was also con¬ tinued along the flanks. Epotides, in naval architecture, two thick blocks of wood, one on each side the prow of a galley, for ward¬ ing off the blows of the rostra of the enemy’s vessel. Equation, an equal division: in alge¬ bra, a mutual comparing of things of different denominations: in as¬ tronomy, the difference between the apparent and mean motion of the sun. Equilateral, having all sides equal. Equilibrium, equipoise, equality of weight. Equilibrium valve, the valve in the steam passage of a Cornish engine for opening the communication be¬ tween the top and bottom of the cylinder, to render the pressure equal on both sides of the piston. Era. The year 5611 of the Jewish era commenced September 7,1850 ; Ramadan, the month of abstinence observed by the Turks, July 11, 1850 ; the year 1267 of the Mo¬ hammedan era, Nov. 6, 1850; and the Christian era, 1849 since the birth of Jesus Christ, for 1850 vears, on the 1st of January, 1850. Erasement (applied to buildings and cities), entire destruction and de¬ molition. Ergastulum, a sort of prison or house of correction contiguous to the farms and country villas of the Romans. Ergata, a capstan or windlass. Erisma, an arch-buttress, shore-post, or prop, to hold up buildings. Euripus, an arm of the sea with land on both sides; a canal, a pool, or stand of water; ditch, a trench or moat about a place ; a water-pipe of the smaller size, so made that the water therein may mount aloft: also an inlet or small creek. Escape, the scape of a column in ar¬ chitecture. Escutcheon, a shield charged with armorial bearings. Etching, a branch of engraving in which the lines are drawn by a stylus or etching-needle, on copper, steel, or stone, prepared by a che¬ mical process. Eudiometer, an instrument used to ascertain the purity of air, or rather the quantity of oxygen contained in any given bulk of elastic fluid. Eurythmy, in architecture, the exact proportion between all parts of a building. Eustyle, t hat intercolumniation which, as its name would import, the an¬ cients considered the most elegant, viz. two diameters and a quarter of the column. Vitruvius says, this manner of arranging columns ex¬ ceeds all others in strength, conve¬ nience, and beauty. j Evangelists, The. In the Table of Symbols of the early ages, by the four Mystic Animals, Rev. iv. 7 :— The Angel being assigned to St. Matthew, the Lion to St. Mark, the Ox to St. Luke, and the Eagle to St. John ; and the four rivers issuing from the Mount of Paradise to enter the earth, Gen. ii. 10. Evaporation, the transformation of a 183 EXPANSIVE STEAM. EVO liquid into a gaseous state by the action of heat. Evolute, a particular species of curve. Evolution, in geometry: the equable evolution of the periphery of a cir¬ cle, or any other curve, is such a gradual approach of the circum¬ ference to rectitude as that all the parts meet together, and equally evolve or unbend. Ewry, an office of household service, where the ewers, etc., were for¬ merly kept. Examen, the tongue on the beam of a balance, rising perpendicularly from the beam, and moving in an eye affixed to the same, by which it serves to point out the equality or inequality of weight between the objects in the scale. Excalefaction, heating or warm¬ ing. Exedra, an assembly-room or hall of conversation ; according to Vitru¬ vius, a large and handsome apart¬ ment; also a by-place, or juttv. Exedra, or Exhedra, the portico of the Grecian palaestra, in which dis¬ putations of the learned were held : so called from its containing a number of seats, generally open, like the pastas or vestibule of a Greek house. Exemplar, a pattern, plan, or model; resemblance. Exhaust-port, the exit passage for the steam from a cylinder. Exhaust-valve, the valve in the educ¬ tion passage of the steam cylinder of a Cornish engine,placed between the cylinder and air-pump, and worked by the tappet motion, so as to open shortly after the equili¬ brium valve, and admit the steam to the condenser. Existence, being, entity, subsistence, reality, actuality, positiveness, ab¬ soluteness, fact.—Verb : to be, to exist, have being, subsist, live, breathe. Expansion-joint, a stuffing-box joint connecting the steam-pipes, so as to allow one of them to slide within the enlarged end of the EXP other when the length increases by expansion. Expansion-valve, an auxiliary valve placed between the slide-valve and the steam cylinder : it is worked by a cam or other contrivance, so as to cut off the steam at a given pe¬ riod, and cause the remainder of the stroke to be performed by ex¬ pansion. Expansive steam. The expansive pro¬ perties of steam are now well un¬ derstood, and extensively applied to practice in manufacturing dis¬ tricts. In Cornwall, and in some other parts of the kingdom, the ap¬ plication is attended with highly beneficial results. But it should be stated that this system can be introduced with much greater ad¬ vantage in engines that are em¬ ployed in raising water, than in those which are entirely devoted to manufacturing purposes. In these last, the power is opposed to a continually varying resistance ; while, in the former, the resistance is commonly the same, or of equal intensity. To pumping engines, the adop¬ tion of the expansive system to an almost unlimited extent is recom¬ mended, even to the exclusion of any further ingress of steam to the cylinder after the piston has passed through but one-eighth or one- ninth of its stroke. Expansive steam may be thus explained :—If we allow steam to flow into the cylinder of a steam- engine until the piston be de¬ pressed to one-half of the stroke, and then prevent the admission of any further quantity, the piston will, if the engine be properly weighted, continue its motion to the bottom. The pressure of the steam, so long as the supply is continued from the boiler, will be equal, it is presumed, to ten pounds upon the inch. With this force it will act upon the piston until it completes one-half of the stroke: the further supply of steam will 184 EXP EXPRESSION. EXT then he excluded, and that which is in the cylinder will expand as the piston descends, so that when the stroke is completed it will occupy the entire capacity. The pressure of the steam will then be half of its former amount, or five pounds upon the inch. During the descent of the pis¬ ton, the pressure of the steam does not suddenly decrease from ten pounds to five; but it gradually declines, through the successive intervals, until at the final point it yields that force. It is by this gra¬ dual expansion and diminution of pressure that the superior action is produced. Experiments on Brass. Dr. Young made some experiments on brass, from which he calculated the height of the modulus of elasticity of brass plate to be 4,940,000 feet, or 1 8,000,000 Its. for its weight to a base of 1 square inch. For wire of inferior brass he found the height to be 4,700,000 feet. As cast brass had not been sub¬ mitted to experiment, a cast bar of good brass was procured, with which the following experiment w as made : The bar was filed true and regu¬ lar: its depth was 0 - 45 inch, and breadth 0‘7 inch ; the distance be¬ tween the supports was 12 inches, and the scale suspended from the middle. Hence 52 lbs. seems to be about the limit which could not be much exceeded without permanent change of structure. It is equiva¬ lent to a strain of 0700 lbs. upon a square inch, and the corresponding extension isof its length. Ab¬ solute cohesion above 21,000 lbs. per square inch. The modulus of elasticity according to this experi¬ ment is 8,930.000 lbs. for a base of an inch square. The specific gra¬ vity of the brass is 8 37, whence we have 2,460,000 feet for the height of the modulus. Expression principally consists in re¬ presenting the human body and all its parts in the action suitable to it; in exhibiting in the face the se¬ veral passions proper to the figures, and marking the motions they im¬ press on the other external parts. Expression , in painting, con¬ sists in the representation of those attitudes of the body, and varia¬ tions of the countenance which always accompany and indicate the immediate influence of the pas¬ sions on the mind. Expression of colour. Every pas sion and affection of the mind has its appropriate tint; and colour¬ ing, if properly adapted, lends its aid, with powerful effect, in the just discrimination and forcible ex¬ pression of them : it heightens joy, warms love, inflames anger, deep¬ ens sadness, and adds coldness to lbs. inch. the cheek of death itself. 12 bent the bar 0 01 External thermometer (the) should 23 . . . 0'02 be a mercurial one, well exhausted of air, and the graduated scale di- fThe bar was vided to tenths of a degree, or into 38 q,q 2 j relieved seve- quarters of a degree, or w ith whole 52 ! ral times, but . 0 04 1 .. . . | it took no per- divisions large enough to be di- vided into as many parts by the (_ceptible set. eye. Choose a locality for the 65 . „ n - j Relieved, the instrument, where it will be well ' 1 set was -01. exposed to the ambient air,—apart 110 . . 0-18 from the reflection of sunbeams, C slipped between the etc.,—and where it may be dis- 163 . J supports, bent more tinctly read off without inconve- | than 2 inches, but did nience. It should be lead off as ! not break. quickly as possible. For uniformity 185 EXT FAHRENHEIT. of system, it should be read off at stated periods, the same time at which the barometer, etc., are noted, and carefully watched in the interim, to see whenever any remarkable change occurs ; before and after storms, during eclipses of the sun and moon, or the passage of dense clouds of vapour, etc. Extract of gamboge is the colouring matter of gamboge separated from its greenish gum and impurities by solution in alcohol and precipita¬ tion, by which means it acquires a powdery texture, rendering it mis¬ cible in oil, etc., and capable of F. Faber, a name given by the Romans to any artisan or mechanic who worked in hard materials. Fabrica, according to the Romans, the workshop of any mechanic. Fabrication , the art of building, con¬ struction. Fabrillia, according to Horace, me¬ chanics’ tools. Fagade, the face or front of any con¬ siderable building to a street, court, garden, or other place. Face-piece , in ship-building, a piece wrought on the fore-part of the knee of the head, to assist the con¬ version of the main-piece, and to shorten the upper bolts of the knee of the head. Fagg (sea term) the ends of those strands which do not go through the tops, when a cable or rope is closed. Fagot of Steel, 120 lbs. weight. Faithful (the), (on the table of sym¬ bols of the early ages), represented by sheep, John x. 14; by fish, Matt, xii. 47 ; by doves eating grapes or ears of corn ; by stags, Psalm xlii. 2 ; by date-trees or cedar-trees, Isaiah i. 13 ; Jerem. xvii. 8 ; by little children. Fahrenheit, a native of Dantzic, was born in 1686 : he invented the scale called after his name : he also im¬ proved the thermometer by sub- FAN use in glazing. It is at the same time improved in colour, and re¬ tains its original property of work¬ ing well in water and gum. Extrados, the exterior curve of an arch, measured on the top of the voussoirs, as opposed to the soffit or intrados. Ege, a name given to certain circular parts and apertures in architecture, but more especially to the central circle of the Ionic volute; to the circular or oval window in a pedi¬ ment ; to a small skylight in a roof, or the aperture at the sum¬ mit of a cupola. stituting mercury instead of spirits of wine, and formed a new scale for the instrument, founded on ac¬ curate experiments, fixing the freez¬ ing point of water at 32°, and that of boiling at 212°. Faldstool, or folding stool, a portable seat made to fold up in the manner of a camp-stool: it was made either of metal or wood, and sometimes covered with rich silk. False red is a second red, which is sometimes put under the first, to make it deeper. False stem in a ship, when the stem being too flat, another is fastened to it. False-roof, the space between the ceiling and the roof above it, whe¬ ther the ceiling is of plaster or a stone vault, as at King’s College chapel, Cambridge, and St. Jacques church, Liege. Fan-tracery vaulting : this was used in late Perpendicular work, in which all the ribs that rise from the springing of the vault have the same curve, and diverge equally in every direction, producing an ef¬ fect like the bones of a fan: very fine examples of it exist in Henry the Vllth’s chapel, Westminster St. George’s chapel, Windsor, and in King’s College chapel, Cam bridge. illl FAN FARM. FEED Fan, used in smithies and foundries, by means of which the smith can heat his work with precision, and vary the size of his nozzle tuyere without lowering the intensity of the blast, and he can heat one piece of work while shaping another. Fanal, a pharos or lighthouse, or the lantern placed in it. Fan-light, a window in shape of an open fan ; the light placed over a doorway. Fang, in mining, a niche cut in the side of an adit, or shaft, to serve as an air-course : sometimes a main of wood-pipes is called a fanging. Fanners, vanes or flat discs revolving round a centre, so as to produce a current of air ; generally used in¬ stead of bellows for forges. Fanum, a Roman temple or fane, usually consecrated to some deity. Farm, in Cornish mining, that part of the lord’s fee which is taken for liberty to work in tin-mines only that are bound, which is gene¬ rally one-fifteenth of the whole. Fascia, a flat architectural member in an entablature or elsewhere; a band or broad fillet. The architrave in the more elegant orders of archi¬ tecture is divided into three bands, which are called fasciae: the lower is called the first fascia, the middle one the second, and the upper one the third fascia. Fasciae, the bands of which the epi- stylium of the Ionic and Corinthian orders are composed. The ante- pagments of Ionic doorways were generally divided into three fasciae or corsae. Fasciae were also bands which the Romans were accus¬ tomed to bind round the legs. Fast and loose pulleys, two pulleys placed side by side on a shaft which is driven from another shaft by a band: when it is required to stop the shaft, the band is trans¬ ferred to the loose pulley. Fastigium, the pediment of a portico ; so called because 'it followed the form of the roof, which was made like a triangle, the sides being equally inclined, to carry off the water. In architecture, the sum¬ mit, apex, or ridge of a house or pediment. Fat, see Vat, a large tub, cistern, or vessel used for various purposes by brewers, tanners, etc. Also, a measure of capacity, differing in different commodities. Faubourg, the suburbs, or such por¬ tion of a French town as were suburbs at an earlier date. Fausse-braye, a small mound of earth thrown up round a rampart. Faux, according to Vitruvius, a nar¬ row passage which formed a com¬ munication between the two prin¬ cipal divisions of a Roman house, the atrium and peristylium. Fay, in ship-building, to join two pieces of timber close together. Feathering or foliation, an arrange¬ ment of small arcs or foils sepa¬ rated by projecting points or cusps, used as ornaments in the mould¬ ings of arches, etc., in Gothic archi¬ tecture. Feed-head, a cistern containing water and communicating with the boiler of a steam-engine by a pipe, to supply the boiler by the gravity of the water, the height being made sufficient to overcome the pressure within the boiler. Feed-pipe, the pipe leading from the feed-pump, or from an elevated cistern, to the bottom of the boiler of a locomotive engine. Feed pipe cocks, those used to regulate the supply of water to the boiler of a locomotive engine,and the handle of which is placed conveniently to open and shut at pleasure. Feed pipe strainer, or strum, a perfo¬ rated half-spherical piece of sheet- iron, after the manner of the rose end of a watering-pot: it is placed over the open end of the feed-pipe in the locomotive tender tank, to protect it. Feed-pipes, the copper pipes reaching from the clack-box to the pump and from the pump to the tender, FEED FENESTRATION. FEN to convey water to the boiler of a locomotive engine. Feed-pump, a forcing-pump, worked by the steam-engine, for supplying the boiler with water. Feed-pump plunger, the solid piston, or enlarged end of the pump-rod, fitting the stuffing-box of the pump of a steam-engine. Feldspar or Felspar, a mineral of foliated structure. This important mineral is chiefly interesting in the useful arts on account of its fur¬ nishing, by a natural process of decomposition, the celebrated kao¬ lin, used in making porcelain or china ware. Felspar is composed of silica 64'20, alumina 18’40, and potash 16 95. According to some chemists it may be regarded as a silicate of alumina with silica of potash. Felspar also furnishes some soils with potash. Accord¬ ing to Liebig, a single cubic foot of felspar is sufficient to supply an oak copse, covering a surface of 26,910 square feet, with the potash required by the trees for five years. Feldspatliic or Feldspathose, pertain¬ ing to feldspar, or consisting of it. Fell, a barren or stony hill; a field. Felling timber, the act of cutting down a full-grown tree, which doubtlessly should be done late in the autumn, when less moisture exists in all trees, and which ren¬ ders the timber less liable to dry- rot. Felly or Felloe, the rim of a wheel supported by the spokes. Felsite, a species of compact feldspar, of an azure blue or green colour, found amorphous, associated with quartz or mica. Felt, a cloth or stuff made of wool, or wool and fur, fulled or wrought into a compact substance by rolling or pressure with lees or size or with asphalt. With the latter it is used for roofing; with the former for carpets, hats, etc. Felucca, in navigation, a little vessel used in the Mediterranean, capable 188 of going either stem or stern fore¬ most ; also a small open boat, rowed with six oars. Female-screw , the spiral threaded cavity into which another screw works. Femerell, a lantern, louvre, or cover¬ ing placed on the roof of a kitchen, hall, etc., for the purpose of venti¬ lation or the escape of smoke. Femur, in architecture, the long, flat ! projecting face between each chan¬ nel of a triglvph ; the thigh, or a covering for the thigh. Fence, a wall, ditch, hedge, bank, line of rails or posts, of boards or pickets; a guard, anything to re¬ strain entrance; a defence. Fender-piles, those driven to protect I work either on land or water. Fenders, to vessels or ships, are j pieces of old ropes, or wooden I billets, hung over the side to pre¬ vent injury from collision. Fender-bolts are iron pins for the | protection of the sides of ships. Feneste/la, the niche at the side of an altar containing the piscina ; also a little window. Fenestra, a window, an entrance. Fenestrai: window-blinds, or case¬ ments closed with paper or cloth. Fenestration, termed by the Germans Fenster-architektur, is, in contra- I distinction to columniation, the j] system of construction and mode ' of design marked by windows. Fe¬ nestration and columniation are so far antagonistic and irreconcilable, j that fenestration either interferes with the effect aimed at by colum- , niation with insulated columns, as in a portico or colonnade, or re¬ duces it, as is the case with an engaged order, to something quite secondary and merely decorative.' Astylar and fenestrated ought, therefore, to be merely convertible! terms ; but as they are not, that of: columnar fenestrated has been in¬ vented, to denote that mode ot composition which unites fenestra¬ tion with the semblance, at least of the other. Employed as a col- FER FINLAYSON’S TABLES. FIN lective term, fenestration serves to express the character of a building or design with regard to the win¬ dows generally: thus it is said, the fenestration is excellent, or the contrary,—ornate or meagre,—well arranged or too crowded,—which last circumstance is a very common fault, and is destructive both of grandeur and of repose. Feretory , a bier, or coffin; a tomb, or shrine. Ferrari (Gaudenzio), called by Vasari Gaudenzio Milanese, w’as ranked among the seven greatest painters in the world. Ferrule , a metal ring fixed on the handle of a tool to prevent the wood from splitting. Festoon , an ornament of carved work, representing a wreath or garland of flowers or leaves, or both inter¬ woven with each other: it is thick¬ est in the middle, and small at each extremity, a part often hanging down below the knot. Festoon, in architecture, an ornament of carved Work, in the form of a wreath or garland of flowers, or leaves twisted together. Fictile, an earthen vessel or other article, moulded and baked. Fictor, among the Romans, an artist, a deviser, or potter. Fid-hammer, a tool;—a Add at one end and a hammer at the other. Fidd is a piece of iron or wood to open the strands of ropes. Fife-rails of a ship are banisters on each side of the top of the poop. Figulus, an artist who makes figures and ornaments. Filagree, in the arts, a kind of en¬ richment in gold and silver. File, a well-known instrument having teeth on the surface for cutting metal, ivory, wood, etc. File, a strip or bar of steel, the sur¬ face of which is cut into fine points or teeth, which act by a species of cutting closely allied to abrasion. When the file is rubbed over the material to be operated upon, it cuts or abrades little shavings or shreds, which, from their minuteness, are called file-dust, and in so doing the file produces minute and irregular furrows of nearly equal depth, leav¬ ing the surface that has been filed more or less smooth, according to the size of the teeth of the file, and more or less accurately shaped, ac¬ cording to the degree of skill used in the manipulation of the instru¬ ment. The files employed in the mechanical arts are almost endless in variety. Fillet, a small flat face or band, used principally between mouldings to separate them from each other in classical architecture: in the Gothic, Early English, or Decorated styles of architecture, it is also used upon larger mouldings and shafts. Finial, sometimes called a pinnacle, but more truly confined to the bunch of foliage which terminates pinnacles, canopies,pediments, etc., in Gothic architecture. Finite force, a force that acts for a finite time, such as the force of gravity. Finlayson’s Tables of the value of life assurance and annuities differ in several respects w idely from either the Northampton or the Carlisle calculated Tables. In framing them for Government annuities, from ob¬ servations made on the mortality in tontines and amongst the holders of Government annuities, Mr. Fin- lavson, in his calculations, is in¬ clined to take a favourable view of the duration of human life, and his Tables coincide very nearly with the Carlisle, except that he makes a distinction between males and females,—the latter being consi¬ dered rather longer lived than the former. As regards annuities, these observations may be thus illus¬ trated : the present value of an an¬ nuity of £1 for the life of a person aged twenty-five, calculated at 4 per cent, interest, would be, ac¬ cording to the £. s. Northampton Tables 15 4 FIR Carlisle Tables . . .£17 6 Government, Male . .16 9 Do. Female . 18 1 Fire-bar frame, in a locomotive engine, a frame made to fit the fire-box on which the fire-bars rest: a plan of dropping all the bars at once by a movable frame, acted on by a lever and handle outside the fire-box, has been frequently tried, but the action of the intense heat soon puts it out of working order. Fire-bars, in a locomotive engine, wedge-shaped iron bars fitted to the fire-box with the thick side uppermost, to support the fire: the ends rest on a frame : they are in¬ clined inwards, with an air space between each, to promote combus¬ tion, and are jointed at one end, and supported by a rod at the other, so that the rod being with¬ drawn, the bars fall, and the fire- i box is emptied. Fire-box, in a locomotive engine, the box (usually made of copper) in which the fire is placed. The out¬ side is of iron, separated from the copper fire-box by a space of about 3 inches all round for water. Fire-box door, the door opening into the fire-box, facing the locomotive tender, by which coke is supplied to the fire. Fire-box partition: in large fire¬ boxes a division is made in the box, into which water is admitted: this division is about the height of the fire-box door, and divides the fire into two parts in a locomotive en¬ gine, thereby increasing the heating surface of the fire-box. Fire-box stays, in a locomotive engine, deep strong iron stays bolted to the top of the copper fire-box, to enable it to resist the pressure of the steam: round copper or iron stays are also used to connect the outside shell to the inside box, in the proportion of about one stay to every 4 square inches of flat surface. Fire-bricks are used for lining fur¬ naces, and for all kinds of brick¬ work exposed to intense heat which FIR i would melt common bricks. They are made from a natural compound of silica and alumina, which, when free from lime and other fluxes, is infusible under the greatest heat to which it can be subjected. Oxide ! of iron, however, which is present in most clays, renders the clay fu- j sible when the silica and alumina are nearly in equal proportions, and those fire-clays are the best in which 1 the silica is greatly in excess over | the alumina. When the alumina is in excess, broken crucibles, glass- a house pots, and old fire-bricks, I ground to powder, are substituted l{ for the common siliceous sand used « in the ordinary processes of brick- I making, but which, in this case, ] would be injurious, as having a tendency to render the clay fusible. Fire-clay being an expensive ar¬ ticle, it is usual, when making fire- . bricks at a distance from mines, to mix with it burnt clay, for the sake of economizing the clay and j diminishing its contraction. Mr. Pellatt states that Stourbridge clay, : 1 when carefully picked, ground, and | > sifted, will bear, for brick-making, ] two proportions (by weight) of burnt clay to one of native clay. Fire-clay is found throughout the j . coal formation, but that of Stour- i bridge is considered the best. The j fire-clays of Newcastle and Glasgow are also much esteemed. Fire- 1 bricks are brought to London from Stourbridge and from Wales; the i latter, however, will not stand such intense heat as the Stourbridge bricks. Fire-bricks are also made at the village of Hedgerly, near Windsor, of the sandy loam known by i the name of W'indsor loam, and these are much used in London for fire-work, and also by chemists for luting their furnaces, and for similar purposes. The relative merits of Windsor, Welsh, and Stourbridge fire-bricks are best shown by their value in the market. FIRE-BRICKS. 190 FIREPROOF FLOORS. FIR FIR The following Table shows the constituents of several infusible clays:— iron ores, glass-making, etc., and sometimes for the linings of retort- ovens: for this latter purpose they Authority . . Dr. Ure. Vauquelin. Wrightson. Description. Kaolin, or porcelain clay. Plastic clay of Forge-les-eaux. Sagger clay, from the Staffordshire potteries. Silica . . . 52 63 54-38 Alumina 47 16 26"55 Iron.... 0-33 8 8-38 Lime . . . — 1 — Carbonic acid . — — 3-14 Water . . . — 10 7-28 9933 98 99-73 ( Used for making Used for making Remarks . . glass-house pots saggers and fire- (. and pottery. bricks. The following prices are from the ‘Contractor’s Pocket-Book for 1850.’ They include carriage to London and delivery on the works : Fire-bricks per m. £. s. d. Windsor ... 5 8 0 Welsh ... 8 12 0 Stourbridge. .11 6 0 Fire-brick*. The parts of furnaces exposed to heat are built of bricks made of a description of clay which is to different extents infusible, the qualities chosen for use being regu¬ lated by the degree of heat to which they are to be exposed. They are known in commerce by the names of Bristol, Stourbridge, Newcastle, Welsh, and Windsor bricks. The first of these are composed almost entirely of silex, and are infusible at the greatest heat of the blast¬ furnace ; but they are very costly, and seldom used. The second quality are made from clay found in the neighbourhood of Stour¬ bridge, lying in a stratum of con¬ siderable thickness between the upper soil and the coal formations : they are used in the construction of furnaces required to resist great heat, such as those for smelting are considered too expensive, ex¬ cept for the arch immediately over the furnace, as the heat is not in¬ tense. The third variety are com¬ posed of the clay lying above the coal measures in Northumberland, and for the construction of retort furnaces and ovens are the most desirable. Fire-damp , in coal-mines, is impure carburetted hydrogen. Fire-place, a space within a chimney- piece for the burning of fuel to warm the temperature of the air, and in communication with a shaft or chimney-flue. Fireproof floors. When a fire breaks out in London it destroys a whole building in spite of the prompt ef¬ forts of the Brigade; this is owing to the materials used in the con¬ struction of houses being very in¬ flammable. In an enlightened country like England, so rich in iron, and commanding such power¬ ful means of action, we ought to have got rid altogether of wooden floors and roofs, which are so ex¬ pensive, so combustible, so apt to wear out. In Paris there are firms who 191 FIR FIRES OF THE ANCIENTS. FIR manufacture iron roofs and floors. The Exhibition contained numerous samples of this manufacture, espe¬ cially those exhibited by theCreu- sot Foundry, consisting of a flooring with its various modes of construc¬ tion, all worthy the attention of competent judges. The Creusot manufacture girders offering a re¬ sistance of 18 to 20 per cent, above that obtained by any other system, independently of the extra strength produced by the peculiar mode in which they are riveted. The usual price of iron girders in England is from 30 to 40 per cent, cheaper than in Paris, and the timber joisjts are from 30 to 40 per cent, dearer; the former are gene¬ rally preferred in Paris on account of their greater durability and their being fireproof. There are firms supplying rolled iron girders in London ; plate gir¬ ders have been found by several builders more economical than rolled ones, and there is no lack of them. The iron girders are prevented from oxidation when imbedded in mortar, and not in plaster. In all the French systems the wooden floors (‘ parquets’) are laid on small wooden joists, resting on the top of the main girders, which allows the ventilation required for preventing the ‘ dry rot.’ Fire-tubes , or tube-flues, are those through which the fire passes, for obtaining a large heating surface, fixed longitudinally in the middle compartment of a locomotive en¬ gine, between the fire-box and smoke-box. Fires of the Ancients. Palladio says, —“ Finding that this subject about fires of the ancients had not been treated of distinctly by anybody, I resolved to compose something about it. We are ignorant of most things delivered thereupon by the ancients which might give us some light upon the matter : we must have recourse to the inventions of later times, thereby gradually to obtain a more ample knowledge of it. The Romans were sensible that a continual flame and a great heat from live coals were hurtful to the eyes; they therefore went very wisely about finding out a remedy. They found how dangerous it was to carry fire about the house from one room to another. Stoves are an abominable invention : they cause a continual stench, swell the head, and make men drowsy, dull, and lazy. Most people that use them grow tender and weak: some cannot stir out of these rooms all the winter. The ancients used to light their fire in a small furnace under the earth. Thence they conveyed a great many tubes of different sizes into all the different stories and rooms of the house, which tubes or pipes were invisi¬ ble, but laid in the thickness of the walls and ceilings, just like water- pipes. Each of these opened at that part of the furnace which joined to the very wall of the house, and through these ascended the heat, which was let in whenever they had a mind it should, whether in dining-rooms, bed-chambers, or closets, much in the manner as we see the heat or steam of water contained in an alembic to ascend and warm the parts most distant from the fire-place. The heat in that manner used to spread so equally that it warmed the whole house alike. It is not so with chimneys or hearths; for if you stand near, you are scorched; if at any distance, you are frozen ; but here a very mild warm air spreads all around, according as the fire that warms t he pipes laid along the wall opposite to the hearth is more or less burning. Those pipes which dispensed the heat did not open into the very furnace, on purpose that neither smoke nor flame should get into them, but only a warm steam should enter, which they let out again ; thereby creating a con-j FLAMBOYANT STYLE. FLA FIR tinual moderate heat. The fire needed not to be large, provided it was continual, to supply those confined and enclosed pipes with a sufficient power of warming. They dressed their meat at the mouth of the furnace ; and all along the walls were disposed kettles, or other vessels, filled with hot water, to keep the meat warm.” Fire-brick, a brick that will sustain intense heat without fusion. In the Yale of Neath, in Glamorgan¬ shire, is a layer of clay superposed on a bed of limestone, and consists almost entirely of silica or sand the colour of which when dry is a pale grey. The rock is crushed between iron rollers: it softens by exposure to the atmosphere, but some of it is too hard for making into bricks. The powder thus obtained is mixed with a small • proportion of lime when that sub¬ stance is not previously contained in it, and sufficient water to make itcohere slightly by pressure. This mixture is compressed in iron moulds, two of which are placed side by side under one press. Each mould is open top and bottom, is closed below by a movable iron plate, and above by another iron plate, which fits like a piston, and is connected with a lever. The workmen put on good stout gloves to protect their hands from the rough edges of the fragments, adjust the machine, and fill the moulds with the coarse powder. The piston is then pressed down, the bottom plate of iron is taken out from below, the brick still re¬ maining on it, and is so conveyed to the drying sheds. At this stage the brick is too soft to allow of being directly handled, and there¬ fore it is removed on the iron plate. When dry the bricks are piled up in dome-shaped kilns, where they remain about a fortnight, a week being allowed for firing the bricks, and a week for the kiln to cool. Fir-poles, small trunks of fir-trees, from 10 to 16 feet in length; used in rustic buildings and out-houses. Fisk, a machine employed to hoist and draw up the flukes of a ship’s anchor towards the top of the bow, in order to stow it after it has been catted. Fissure, or Gulley, is the crack or split in the strata of the earth which is the receptacle of mineral particles, whose contents are styled a ‘ lode.’ Fistuca, among the Romans, an in¬ strument used for ramming down pavements and threshing-floors, and the foundations of buildings. Fistula, a water-pipe, according to Vitruvius, who distinguishes three modes of conveying water: by leaden pipes, by earthen pipes, and by channels of masonry. Flag, a national colour, a standard. Flag, a stone for pavement. Flake-white is an English white lead, in the form of scales or plates, sometimes grey on the surface. It takes its name from its figure, is equal or sometimes superior to cream white, and is an oxidized carbonate of lead, not essentially differing from the best of the above. Other white leads seldom equal it in body; and when levi¬ gated, it is called ‘ body-white.’ Flamboyant Style of Architecture, the decorated and very ornamental style of architecture of French in¬ vention and use, and contemporary in France with the Perpendicular style in England. One of the most striking and universal features is the waving arrangements of the tracery of the windows, panels, etc. The foliage used for enrichments is well carved, and has a playful and frequently good effect. Flanders varnish: dissolve grain mastic in alcohol: this operation is requisite to detach the impurities in the resin. The proportion of spirit ought to be sufficient to cover the mastic, and \ part more. Flanning, the internal splay of a win- dow-jamb. 193 s FLA FLORENTINE SCHOOL. FLO Flaring, in ship-building, over-hang¬ ing, as in the top side forward. Flatting, in house-painting, a mode of painting in oil in which the surface is left, when finished, with¬ out gloss. The material is pre¬ pared with a mixture of oil of tur¬ pentine, which secures the colours, and, when used in the finishing, leaves the paint quite dead. Flemish bricks are used for paving : seventy-two will pave a square yard: they are of a yellowish colour, and harder than the or¬ dinary bricks. Flemish School of Painting. This school is highly recommended to the lovers of the art by the disco¬ very, or at least the first practice, of painting in oil. It has been generally attributed to John Van Eyck, who was, it is said, accus¬ tomed to varnish his distemper pictures with a composition of oils, which was pleasing on account of the lustre it gave them. In course of practice he came to mix his colours with oil, instead of water, which rendered them brilliant without the trouble of varnishing. From this and -subsequent experi¬ ments arose thd|irt of painting in oil. The attention of the Italian painters was soon excited. John of Bruges was the founder of paint¬ ing as a profession in Flanders. Fleur-de-Lis, the ancient trophy of France. Flight, the stair from one landing- place to another. Float, a flat piece of stone or other material attached to a valve in the feed-pipe of the boiler of a steam- engine, and supported upon the surface of the water by a counter¬ weight; used either for showing the height of the water, or regu¬ lating the supply from the cistern. Flock-paper has raised figures made of flock. Floohan, in Cornish, an earth or clay of a slimy, glutinous consistence ; in colour for the most part blue or white, or compounded of both. Floor-hollow, in ship-building, an el¬ liptical mould for the hollow of the floor-timbers and lower futtocks. Flooking, among miners, the inter¬ ception of ore by the crossing of a vein of earth or stone. Floors, in early English domestic ar¬ rangements, were generally covered with rushes, carpets being seldom used for such purposes, although instances occur of tapestry cloths for the feet to rest upon as early as Edward I. It does not, indeed, appear to have been the custom at any time to leave floors bare, whether boarded or paved. Floor-timbers , in ship-building, are those placed immediately across the keel, and upon which the bot¬ tom of the ship is framed. Floran, an exceedingly small-grained tin, scarcely perceivable in the stone, though perhaps very rich. Florentine lake colour is extracted from the shreds of scarlet cloth: the same may be said also of Chinese lake. Florentine School of Painting. This school is remarkable for greatness; for attitudes seemingly in motion; for a certain dark severity ; for an 1 expression of strength by which grace is perhaps excluded; and for a character of design approaching to the gigantic. The productions of this school may be considered as overcharged; but it cannot be denied that they possess an ideal majesty which elevates human na¬ ture above mortality. This school has an indisputable title to the veneration of all the lovers of the arts, as the first in Italy which cul¬ tivated them. In the year 1349 the painters established themselves into a religious fraternity, which they denominated ‘The Society of St. Luke’s.’ Florid Gothic, or Florid English or Tudor, is a style of redundant or¬ namentation. The period is from 1400-1537. There are many churches of the time of Henry VII. in Somersetshire. 1 194 , FLO FONT. FON Flotilla, a Spanish term for a num¬ ber of ships, or fleet. Flower-garden (the) “ should be an object detached and distinct from the general scenery of the place; and whether large or small, whe¬ ther varied or formal, it ought to be well protected from hares and smaller animals by an inner fence: within this enclosure rare plants of every description should Ire en¬ couraged, and a provision made of soil and aspect for every different class. Beds of bog-earth should he prepared for the American plants: the aquatic plants, some of which are peculiarly beautiful, should grow on the surface or near the edges of water. The nu¬ merous class of rock-plants should have beds of rugged stone pro¬ vided for their reception, with¬ out the affectation of such stones being the natural production of the soil; but, above all, there should be poles or hoops for those kinds of creeping plants which sponta¬ neously form themselves into grace¬ ful festoons when encouraged and supported by art.” There is no ornament of a flower- garden more appropriate than a conservatory or greenhouse, where the flower-garden is not too far from the house ; but amongst the refinements of modern luxury may be reckoned that of attaching a green-house to some room in the mansion. Fluccan, in mining, a soft, clayey sub¬ stance, generally found to accom¬ pany the cross courses and slides. Fluke, in mining, the head of a charger; an instrument used for cleansing the hole previous to blasting. Fluor or Fluores, a soft, transparent kind of mineral concretion. Flush, a term common to workmen, and applied to surfaces which are on the same plane. Flutings or Flutes, the hollows or channels cut perpendicularly in the shafts of columns, etc., in classical architecture: they are used in the Doric, Ionic, Corinthian, and Com¬ posite orders. Flux, in metallurgy, saline matters which facilitate the fusion of ores and other silbstances which are not easily fusible in assays; used also in the reduction of ores. Fly, in mechanics, that part of a machine which, being put in mo¬ tion, regulates the rest. Fly-wheel, a w'heel with a heavy rim, fixed upon the crank-shaft of a land engine, for the purpose of equaliz¬ ing the motion by the centrifugal force absorbing the surplus force at one part of the action, to dis¬ tribute it again when the action is deficient. Flyers, stairs that go straight and do not wind, the fore and back part of each stair and the ends respectively being parallel to each other. Focus, among the Romans, an altar, a fireplace or hearth: hence the Latin motto, “ Pro aris et focis,” “for our altars and firesides.” Fodina, a mine or quarry. Foye, Cornish, a forge or blowing- house for smelting tin. Foils, foliation; the spaces between the cusps of the featherings of Gothic architecture. Foils, a font or a natural spring of water, frequently converted into or¬ namented fountains by the Greeks and the Romans. The latter also erected edifices of various degrees of splendour over natural springs, such as the grotto of Egeria, near Rome, where the natural cave is converted by the architect into a temple. Font, the vessel which contains the water for the purposes of baptism. The font is the only relic of our ancient architecture w'hich in its form is at all analogous to the Grecian and Roman vases. The shape which has at different pe¬ riods been given to it is a subject of some interest. Norman fonts are generally square or circular; the first frequently placed on five k 2 195 FORCING-PUMP. FOO FOR legs ; but which may be the older form, the square or circle, is not yet known. The circular form continued to he much used during the Early English period ; so, occa¬ sionally, was the square. Through¬ out the continuance of the Deco¬ rated style, the octagon was gene¬ rally used, sometimes the hexagon. During the Perpendicular style, the octagon was almost always used. Until the Reformation, and occa¬ sionally after, dipping was prac¬ tised in this country. Pouring or sprinkling was not unusual pre¬ vious to the Reformation ; for as early as the year 754, pouring, in cases of necessity, was declared hv Pope Stephen III. to he lawful; and in the year 1311, the Council | of Ravenna declared dipping or sprinkling indifferent: yet dipping appears to have been in this coun¬ try the more usual mode. The Earl of Warwick, who was born in 1831, was baptized by dipping: so Prince Arthur (eldest son of Henry VII.), King Edward VI., and Queen Elizabeth, were all baptized in a similar manner. Font of the time of Edward II. Foot, an ancient measure of tin, con¬ taining two gallons ; now a nominal measure, but in weight 60 lbs.; also a lineal measure of twelve inches. Foot-pace , the dais or raised floor at the upper end of an ancient hall. Foot-plate, the platform on which the engine-man and fire-man of a lo¬ comotive engine attend to their duties. Foot-stall, the plinth or base of a pillar. Foot-valve, the valve in the passage between the condenser and air- pump of an engine, opening towards the air-pump. Foot-waleing, the plank wit’ninside a ship, below the lower deck. Force of the wind. Air, when in continuous motion in one direction, becomes a very useful agent of machinery, of greater or less energy according to the velocity with which it moves. Were it not for its vari¬ ability in direction and force, and the consequent fluctuations in its supply, scarcely any more appro¬ priate first mover could generally be wished for; and even with all its irregularity, it is still so useful as to require a separate considera¬ tion. The force with which air strikes against a moving surface, or with which the wind strikes against a quiescent surface, is nearly as the square of the velocity; or, more correctly, the exponent of the ve¬ locity varies between 2 03 and 2'05; so that in most practical cases the exponent 2, or that of the square, may be employed without fear of error. Forceps, tongs used by smiths to take the hot metal from the fire. Force-pumps, the plunger-pumps for supplying the boiler of a locomo¬ tive engine: the plunger-rods are connected to the piston-rods of the steam cylinder. Forcer, in Cornish, a small pump worked by hand, used in sinking small simples, dippas, or pits. Forcing-pump (the) differs but little from a syringe : the latter receives and expels a liquid through the same passage, but the former has "a separate pipe for its discharge, and 196 for forum. for both the receiving and discharging orifices are covered with valves. By this arrangement it is not ne¬ cessary to remove a pump from the liquid to transfer the contents of its cylinder, as is done with the sy¬ ringe, but the operation of forcing up water may be continuous, while the instrument is immovable. A forcing-pump, therefore, is merely a syringe furnished with an induc¬ tion and eduction valve, — one through which water enters the cylinder, the other by which it es¬ capes from it. The ordinary forcing- pump has two valves: the cylinder is placed above the surface of the water to be raised, and consequently is charged by the pressure of the atmosphere : the machine, there¬ fore, is a compound one, differing from that described, which is purely a forcing-pump, the water entering its cylinder by gravity alone. Forecastle , a short deck at the fore¬ part of a ship, above the upper deck, on which castles were for¬ merly erected, or places to shelter the men in time of action. Fore-foot, the foremost piece of the keel of a vessel. Foreground, the front of a picture. Foreyn, an ancient term to signify a drain or cesspool. Forge, a smith’s furnace for heating metals, to render them soft and more malleable. Fork, a short piece of steel which fits into one of the sockets or chucks of a lathe, and is used by wood¬ turners for carrying round the piece to be turned ; it is flattened at the end like a chisel, but has a pro¬ jecting centre-point, to prevent the wood from moving laterally. Fore-locks, in a ship, little flat wedge¬ like pieces of iron, used at the ends of bolts to keep the bolts from fly¬ ing out of the holes. Foreshorten, in painting, is when a head or face in a draught is made to appear shorter before. Fofm: 1. General form : figure,shape, configuration, make, formation, frame, construction, conformation, efformation, mould, fashion.—2. Special form.—3. Superficial form. Formosity, beauty, fairness, etc. Form-peys, an ancient term for form- pieces ; the lower terminations of mullions which are worked upon sills. Forms and motions of tools. The principles of action of all cutting tools, and of some others, whether guided by hand or by machinery, resolve themselves into the simple condition, that the work is the combined copy of the form of the tool and of the motion employed : thus the geometrical definitions employed convey the primary ideas of lines, superficies, and solids; that is, the line results from the motion of a point, the superficies from the motion of a line, and the solid from the motion of a superficies. Formula (pi. Formula), a prescribed rule in arithmetic or mathematics ; a maxim : in law, an action, process, or indictment. Formulary, a book containing set forms, rules, or models. Fornax, among the Romans, a kiln for baking pottery. Fortification, the science of military architecture; a defensive building. Forum, a large open space used by the Romans for the' sale of merchan¬ dise, and for public assemblies; also a court of justice. Forum and Basilica. The Greeks built their forum with spacious porticoes, two tiers in height, ar¬ ranged in a square form ; the co¬ lumns of the porticoes were placed at small intervals from each other, supporting stone or marble enta¬ blatures ; and galleries were made over the lacunaria of the low'er porticoes, or places of exercise. In Italy, the mode of constructing the forum was different; because, by a custom sanctioned by its anti¬ quity, the show of gladiators was exhibited there; and therefore the intervals between the columns sur¬ rounding the area w r ere greater. 197 FOS FOSSES D’AISANCES. FOS ; The lower porticoes were occupied as the offices of bankers, which sit¬ uation was calculated to facilitate the management of the public re¬ venue : the upper contained seats for the spectators of the diversions practised in the forum. Forward , the fore part of a ship. Fosses d'Aisances: the cesspools of Paris are so called; and they are usually made 3 m -00 long in the clear by l™-70, by l ra -50, to the springing of the semicircular head (9 ft. 10 in. x 5 ft. 7 in. x 4 ft. 11 in. English, nearly) : a man-hole, l m -00 by 0 m -35 is left for the pur¬ poses of emptying and visiting them (3 ft.3 -j?g in. x 1 ft. 2 in.). The walls which surround them, as well as the bottom, are exclusively formed of such materials as are most effi¬ cacious in preventing the filtra¬ tion of the matters contained with¬ in them. Of late years the usual custom has been to employ the meuliere, or mill-stone, bedded in mortar composed of lime and ce¬ ment, the inside being w'ell point¬ ed, and rendered throughout with this mortar. No cesspool is al¬ lowed to be used until after an exam¬ ination, to be certified by the mu¬ nicipal authority. Any infiltration to a neighbour’s property gives a title to damages, and the architect and builder are both responsible for ten years to the proprietor, as also to the neighbours, in case any nuisance arises from defects in the execution of the works. When the cesspools require clean¬ ing, notice is given to the Board of Public Health (‘aux Agents de la Salubrite publique’), who authorize and direct the operations. In win¬ ter these are carried on between 10 p.m. and 7 a.m. ; and in sum¬ mer, between 11 p.m. and 6 a.m. The carts, as well as all the other material of the nightmen, are under the inspection of the above-named officers, and must be, as nearly as possible, both water-tight and air¬ tight. They contain not more than 20 m -00 cube each, or nearly 71 ft. cube English. The contents of the cesspools are usually (especially in the modern houses) sufficiently fluid to allow of their extraction by pumps. In this case a small furnace is placed over the bung of the cart, to burn the gas as it rises : the bung itself is plastered over directly the cart is filled. When the contents are too solid to he pumped out, they are conveyed from below in small ves¬ sels of wrought iron, called 1 tin- ettes,’ holding about 3* feet (-Jgth of a metre cube) each; and the lids are plastered over before the vessels are removed from the cess¬ pool. Of late years a system of what are called ‘ fosses mobiles' has been introduced into the better class of houses. It consists of air-tight tubs, placed in a vault (rendered also as air-tight as possible), which receive the ends of the soil-pipes. These tubs are removed at stated intervals, the openings plastered over, and may in that state be transported at any time of the day. This system obviates the terrible in¬ fection of the old kind of cesspool, and is gaining rapidly. Indeed, as the French people are fond of gilt ornaments in their dwellings, and the gases from the cesspools turn them black at once, unless great precautions be observed in cover¬ ing them, whenever a cesspool is opened, it is easy to understand that the ‘fosses mobiles’ which obviate this inconvenience, should become of general use. Until of late, all the carts were obliged to pass through the Bar- riere du Combat to deposit their contents at the laystalls of Mont- faucon ; but some iievv works have been constructed at Bony, so as to allow the suppression of this gigan¬ tic nuisance at the immediate gates of Paris. The cleaning of the cesspools of Paris is executed by several private 198 FOS FOSSES D’ATSANCES. FOS companies, the most important of which is ‘ La Cotnpagnie Richer,’ who do at least one-half of this business: their capital was about £200,000, in land, plant,and build¬ ings. They employ 150 horses and 300 men, of whom 60 are for the repairs of the plant. Their charge is 8f., 9f., and lOf. per metre cube (35^ feet English, nearly), accord¬ ing to the distance. No cesspool is allowed to be used after being emptied until it has been visited by an ‘ Agent de la Salubrite,’ to ascertain whether it be water-tight. The laystalls of Montfaucon con¬ sist of two large reservoirs, at a high level, into which the carts are emptied. These reservoirs are about 2i acres superficial, and apparently 12 feet deep, with a dam between them, to allow of one being used when the other is being emptied. An overflow drain, with sluice-gates at each end,allows the liquid matter to run off to a large basin on a lower level, where it deposits any¬ thing which may be merely in a state of mechanical suspension. On the banks of this reservoir are some important sal-ammoniac works. In the centre is also a sluice-gate,which allows the surplus liquid matters to pass into two smaller reservoirs, where deposition takes place with¬ out anyinterference from the pump¬ ing apparatus of the chemical works. From thence the waters pass off into four other basins, in which any fertilizing properties they may con¬ tain are precipitated by means of straw, dead leaves, etc., and the water, comparatively pure, is at length let off into the main sewer, which discharges itself into the Seine, below Paris. The surface of the intermediate basins i? about 250 m - by 60 m - (or 3f acres); that of the four last basins is about 350 m- by 110 m ‘ (or nearly 9J acres). These reservoirs do not belong to the city of Paris, and some diffi¬ culties have arisen from the pro¬ posal to remove them : all the carts containing the night-soil being obliged to discharge at Montfau¬ con, the farming of the contents of the basins became a source of considerable profit. They were let on the last occasion for a sum of 500,500francs per annum (£20,020 sterling) ; the previous letting hav¬ ing been 166,000 francs (£6640 sterling). The increased rent and the exorbitant w r ages paid during the republican excitement of 1848 proved injurious to the company. The ground occupied by the town, moreover, is not sufficiently exten¬ sive for the operations connected w'ith the manipulation of the ‘ pou- drette,’ and the company were obliged to rent about 7i acres more land for the purpose of spreading and drying the compost. The land necessary for this operation had been taken on lease by the out¬ going company, and they succeed¬ ed in obtaining a sum of £60,000 for the remainder of their term, as no other land was to be had in the neighbourhood. Therent and labour in conversion costs the company from £12,000 to £16,000 per annum. The'pou- drette ’ is sold to agriculturists at 8 francs le setier, a measure equal to 12 bushels English. In one plan adopted for empty¬ ing the cesspools, the carts are made of strong boiler plate; they are placed under an air-pump, and exhausted; the pipes are con¬ nected with the carts and the cess¬ pools, and the atmospheric pressure on the latter forces up the liquid contents. Investigations have been made respecting the general health of the workmen employed at Mont¬ faucon, the reservoir of all the ex- crementitious matter of a city which contains about 1,000,000 inhabi¬ tants, and it has been ascertained, that although they were not af¬ fected by the cholera in 1849, they are very short-lived men : acute 199 fevers, and gangrene on the slightest accident, carry them off in a fright¬ ful manner. Unfortunately the dwellers in the neighbourhood also are subject to the same action, and the mortality from these causes is very great. The action of the ‘ poudrette ’ upon agriculture is somewhat ex¬ traordinary. In the time of Henri Quatre, the wines of Suresnes were highly esteemed: the vines pro¬ duced little, but of a superior quality: since the poudrette has been used to force them, the quan¬ tity of their produce has been in¬ creased, but the quality has totally changed : from a superior rank, the wines of the neighbourhood of Paris have fallen to that of what is vul¬ garly called ‘ du petit bleu.’ Fossatum, a ditch, or a place fenced ■with a ditch or trench. Fossil, a mineral, many kinds of which are peculiarly and elegantly shaped. Fossiliferous, a geological term ap¬ plied to a district abounding in fossils. ■ Foundations, according to Palladio, ought to be twice as thick as the walls to be raised upon them, so that both the quality of the earth and the greatness of the building are to be regarded, making the foundations larger in a soft and loose ground, or where there is a great weight to be supported. The plane of the trench must be as level as possible, so that the weight may press equally, and not incline more on one side than the other, which occasions the cleaving of the walls. For this reason the ancients were accustomed to pave the plane with. Tivertine; but we most commonly lay planks or beams to build on. The foundations ought to be made sloping, that is to say, to diminish as they rise; but yet in such a manner that the middle of the wall above may fall plumb with the mid¬ dle of the lowest part; which must be also observed in the diminution of walls above ground, because by that means the building becomes much stronger than by making the diminution any other way. Sometimes, to avoid charges, (especially in marshy grounds, where there is a necessity to use piles,) foundations are arched like a bridge, and the walls are built upon those arches. In great build¬ ings it is very proper to make vents through the body of the walls from the foundations to the roof, because they let forth the winds and other vapours, which are very prejudicial to buildings: they lessen the charges, and are of no small convenience, espe¬ cially when there is occasion for winding-stairs from the bottom to the top. If it be neeessary to construct vaults below ground, their foundations must be more substantial than the walls of the buildings which are to be raised upon them. The walls, pillars, and columns of the latter must he placed immediately over those below them, so that solid may bear upon solid ; for if walls or columns project beyond the substructure, their duration must necessarily be short. The value of concrete in founda¬ tions was rendered obvious in a building erected by Mr. Clegg at Fulham, in 1829. The foundation was a quicksand. After the exca¬ vation was got out to the depth of 15 feet, an iron rod sunk, with little more than its own weight, 15 feet more; it was, in fact, as bad a foundation as could possibly occur. In about twelve days after it was built, it had settled bodily down 16J inches, without a crack, or deviating in the least from the plumb. It therefore follows, that the only disadvantage attending a bad natural foundation is the ex¬ pense of making an artificial one. The following extract relates to the erection of an extensive building upon bad ground. “ The building for the Albion 200 FOUNDATIONS. FOU FOU Mills was erected upon a very soft soil, consisting of the ‘ made ground’ at the abutment of Blackfriars’ Bridge: to avoid the danger of settlement in the walls, or the ne¬ cessity of going to a very unusual depth with the foundations, Mr. Rennie adopted the plan of forming inverted arches upon the ground over the whole space upon which the building was to stand, and for the bottom of the dock. For this purpose the ground upon which all the several walls were to be erected was rendered as solid as is usual for building by driving piles where necessary, and then several courses of large flat stones were laid to form the foundations of the several walls; but to prevent any chance of these foundations being pressed down in case of the soft earth yielding to the incumbent weight, strong inverted arches were built upon the ground between the foun¬ dation courses of all the walls, so as to cover the whole surface in¬ cluded between the walls; and the abutments or springings of the in¬ verted arches being built solid into the lower coursesofthefoundations, they could not sink unless all the ground beneath the arches had yielded to compression, as well as theground immediately beneath the foundation of the walls. By this method the foundations of all the walls were joined together so as to form one immense base,which would have been very capable of bearing the required weight, even if the ground had been of the consistency of mud; for the whole building would have floated upon it as a 4 ship floats in water; and whatever sinking might have taken place, would have affected the whole building equally, so as to have avoided any partial depressions or derangement of the walls ; but the ground being made tolerably hard, in addition to this expedient of augmenting the bases by inverted arches, the building stood firm.” When the foundation has been properly disposed of, the brick¬ work may be commenced. The bricks should be well burned, and set with a thin joint, four crosses not occupying more depth than ] If inches. Foundations of Temples. In preparing foundations for works of this kind, it will be first necessary to dig down to a regular stratum, if such is to be met with; and upon this the foundations, constructed with great attention to their strength, are to be laid : their solidity must be pro¬ portioned to the magnitude of the building in contemplation. The piers above-ground, below the co¬ lumns, should be thicker than the diameter of the columns they are to support by one-half, that these substructures, which are called ste- reobatae, on account of their sus¬ taining the whole weight, may be enabled by their greater solidity to support what is built upon them. The bases of the columns, when fixed, ought not to project before the face of the stereobatae on either side. The intervals between the piers should either be made solid by means of piles, or arched over, so as to connect the piers. If no compact stratum is to be found, but the ground, on the con¬ trary, is loose or marshy to a great depth, trenches must be dug, and piles of charred alder, olive, or oak, placed close together, be driven in by means of machines : the inter¬ vals between them should be filled up with charred timber, and upon this substratum the foundations should be formed with solid ma¬ sonry. The foundations being reared to the same level all round, the stylobate is next to be constructed. Upon this the columns are to be arranged, in the manner already described, at intervals which are determined by the species of temple intended to be built, whether pvc- nostyle, systyle, diastyle, or eustyle. In the arseostyle species the co. k 3 201 FOU FREEMASON. FRE lumns may be placed at any dis¬ tance asunder. Foundations of a Bridge: these con¬ sist, properly, of the underground work of the piers and abutments, which it is within the province of a civil engineer to construct: the necessity of firmness and solidity in the execution of such works will be deemed of importance just in proportion to the intended ex¬ tent and magnificence of the struc¬ ture they are designed to support. Foundemaunt, foundation. ( Chaucer .) Foundery , in iron works, the space of six days. Foundry, a place where masses of j metal are melted and run into j moulds, so as to assume the re¬ quired form. Four-way-coclc, a cock having two separate passages in the plug, and communicating with four pipes. Fox-tail wedging, in carpentry. This is done by sticking into the point of a wooden bolt a thin wedge of hard wood, which when the bolt reaches the bottom of the hole, splits, expands, and secures it. Frame, the strong frame-work, out¬ side the wheels, wdiich supports the boiler and machinery on the axles of a locomotive engine. Frame, inside, in locomotive engines. Some engines have the support¬ ing frames within the wheels, and are called inside-framed engines. Besides this frame, resting on the axles, there are also other strong stays from the fire-box to the smoke-box, called inside framing or stays, for supporting the works and strengthening the boiler. Frames, the bends of timbers that are bolted together: in small ships there are two bolts in every shift of timber, and three in large ships. The bolts should be disposed clear of the chain and preventer-bolts, scupper, lodging knee-holts, and port cells. FranJcfort-blacIc is said to be made of the lees of wine from which the tartar has been washed, by burn¬ ing in the manner of ivorv-black. Fine Frankfort-black, though al¬ most confined to copper-plate printing, is one of the best black pigments we possess, being of a fine neutral colour, next in intensity to lamp-black, and more powerful than that of ivory. Fraler-house, the refectory or hall of a monastic establishment. Fredstole, a seat near the altar. Freedom, in drawing, is a bold and spirited manner, with evident li¬ berty of the pencil; i. e. where the drawing is apparently accomplish¬ ed with ease. Freemason, as applied to ancient ar¬ chitecture : a person learned in the art of building, more particularly in ecclesiastical construction, and who, by his learning in the science and his taste in the construction of edifices, travelled from one country to another, and executed models of everlasting renown. The term may also he applied to a free-stone mason, or a cutter and worker in stone, without reference to the so¬ ciety called Freemasons. Free-stone, building stone which may be easily cut into blocks and worked with a chisel; so called from having no grain : it may therefore be cut in any direction. Free-stvff, that timber or stuff which is quite clean or without knots, and works easily, without tearing. French chalk is an indurated mag¬ nesian mineral, employed to re¬ move grease stains. French School of Painting. This school has been so different under different masters, that it is difficult to characterize it. Some of its artists have been formed on the Florentine and Lombard styles, others on the Roman, others on the Venetian, and a few of them have distinguished themselves by a style which may he called their own. In speaking in general terms of this school, it appears to have no peculiar character, and can only be distinguished by its aptitude to 202 FRE FRIARS. imitate easily any impressions ; and it may be added, speaking still in general terms, that it unites in a moderate degree the different parts of the art, without excelling in any one of them. Fresco, a kind of painting performed on fresh plaster, or on a wall co¬ vered with mortar not quite dry, and with water-colours. The plaster is only to be laid on as the painting proceeds, no more being done at once than the painter can despatch in a day. The colours, being pre¬ pared with water, and. applied over plaster quite fresh, become incor¬ porated with the plaster, and re¬ tain their beauty fora great length of time. The Romans cut out plaster paintings on brick walls at Sparta, packed them up in wooden cases, and transported them to Rome. Fret, an ornament used in classical ar¬ chitecture,formed bysmall filletsin- tersecting each otherat right angles. Friars (the orders of) in England and Wales, previous to their abolition, including the Nuns Minoresses, amounted to— Black or Dominican friars. 54 Grey or Franciscan friars . 62 Minoresses or nuns of the order of St. Clare ... 4 Friars of the order of the Holy Trinity for the re¬ demption of captives . . 12 Order of the Carmelites or White friars .... 50 Crutched or Crossed friars 10 Austin friars.32 Friars de pcenitentia or of the sac . 9 Bethlenute friars .... 6 Friction, t he act of rubbing two bodies together, or the resistance in ma¬ chines caused by the contact of different moving parts. Friction is proportional to the pressure ; that is, everything remaining the same, the friction increases as the pres¬ sure increases. Friction-clutch, a shell or box fixed on the end of a driving shaft, fitted by a cotdcal piece which slides on FUL a feather, or raised part, at the end of another shaft, so that it can be engaged at pleasure by the cone being forced into the shell by a lever or screw T . This apparatus is very useful for driving machines, the parts of which are subjected to violent strains, as the pressure upon the clutch can be regulated so as to allow it to slide when the strain is too great to be borne safely by the machine. Frieze, the middle division of an en¬ tablature, that which lies between the architrave and the cornice. Frigairon, a Venetian vessel, built with a square stern, without any fore¬ mast, having only a main-mast and bowsprit. Frigidarium, the cold bathing-room in the baths of the ancients, as w ell as the vessel in w hich the cold water was received. The cold bath : the reservoir of cold water in the hvpocaustum, or stove room, was termed ahenum frigidarium. Friths tool or Freedstool, a seat or chair near the altar, for those especially who sought the privilege of sanc¬ tuary. Frontal, or Fronter, the hanging with which the front of an altar was formerly covered. Fronton , a French word to express an ornament over a door or pediment. Frowy stuff, short or brittle and soft timber. Frumslall, a chief seat or mansion house. Fucus, a name given by the Romans to certain false dyes and paints. Fuel, the matter or aliment of fire. Fulci'um, the prop orsupport by which a lever is sustained. Fullers’-earth, a soft unctuous marl, used by fullers in the process of cleansing cloth, etc. Fulling-mill, an engine or mill, in which cloth is cleansed by being beaten with hammers. Fulminating gold or silver, in che¬ mistry, ammonia combined with the oxides of gold or silver. 203 FUM FURNACE. FUT Fumarium, a chimney; an upper room used among the Romans for collecting the smoke from the lower apartments: used also for smoking or ripening wines. Fuor, among carpenters, a piece nailed upon a rafter to strengthen it when decayed. Furling, in navigation, the wrapping up and binding of any sail close to the yard. Furlong, a measure of length, the eighth part of a mile. Furnace. The furnace is one of the most important parts of the high- pressure engine. The whole action and power of the machine depend on its construction, and on the effect obtained from it, inasmuch as fire is the prime agent. Too much industry, exactitude, and in¬ timate knowledge of the subject, cannot be brought to bear on the construction of the furnace, in order to attain the two great objects of its action ; namely, first, to produce as perfect a combustion of the fuel as possible ; and secondly, to apply as much as possible of the heat so developed effectively to the boiler. These two requirements for a good furnace are, however, not so easily satisfied. Much remains to be ac¬ quired as to the conditions under which the whole of the caloric may be perfectly developed from the fuel, although the best manner of applying the heat to the boiler is well understood. Furniture : anterior to the Tudor age, household furniture was in gene¬ ral of a rude, substantial character; the tables were formed of boards or trestles,, the seats of massive oak benches or stools, and the floors strewed with straw. Furniture of the hall: this consisted of but few articles, such as clumsy oak tables covered with carpet, benches or joined forms of the same material, and cupboards for plate, pewter, ‘treene,’ leather jugs, glass, etc., with a reredos or fire- iron in the centre of the floor, against which fagots were piled and burned, the smoke passing through an aperture in the roof; the fender, formed by a raised rim of stone or tile, and a ‘ fier fork ’ and tongs. Furrings, slips of timber nailed to joists or rafters, in order to bring them to a level, and to range them into a straight surface, when the timbers are sagged, either by cast¬ ing, or by a set which they have obtained by their weight in the course of time. Fuseli (Henry), born 1741 at Zurich ; died April, 1825, aged eighty-four. He painted with little sympathy for repose; he thought there was no dignity without action, no sublimity without exaggeration. He left upwards of eight hundred sketches, besides splendid pictures. Fusion, a founding or melting, running metals into fluids. Fust, the shaft of a column from the astragal to the capital. Fusarole, in architecture, a moulding or ornament placed immediately under the echinus in the Doric, Ionic, and Composite capitals; the shaft of a column, pilaster or pillar, or that part comprehended between the shaft and the capital. Fustic, a wood of a species of mul¬ berry growing in most parts of South America, the United States, and the West Indies : it is a large and handsome tree, principally used for dyeing greens and yellows, and also in mosaic cabinet-work and turnery. Futtock, in ship-building. Every single timber is called a futtock, and distinguished by the terms lower, or first, second, third, etc., except the floors, long and half-tim¬ bers, top timbers, stern timbers, etc. Futtocks, the lower timbers raised over the keel, and which hold the ship together. Futtock shrouds, in ship-rigging, small shrouds that go from the main¬ mast, fore-mast, and mizen-mast shrouds to those of the top-mast. 204 GAMBOGE. GAM GAB Gr. Gable, the upright triangular end of a house, from the cornice or eaves to the top of the building, some¬ times called a sloped roof; the up¬ per part of a wall, above the level of the eaves. Examples in Eng¬ lish and foreign Domestic and Go¬ thic architecture are various, and generally have a most picturesque effect. Gablets, small ornamental gables or canopies formed over tabernacles, niches, etc. Gad, in mining, a small punch of iron with a long wooden handle, used to break up the ore. Gaff, a sort of boom used in small ships to extend the upper edge of the mizen, and employed for the same purpose on those sails whose foremost edges are joined to the masts by hoops or lacings, and which are usually extended by a boom below: such are the main¬ sails of sloops, brigs, and schooners. Gage or Gauge, an instrument used for measuring the state of rare¬ faction in the air-pump, variations in the barometer, etc.; a measure, a standard. Gainsborough, the painter, was born in 1727, in Sussex. His price for a portrait rose from 5 guineas to 8, and until he had 40 guineas for a half and 100 guineas for a whole length. Like Reynolds, he painted standing in preference to sitting; he rose early, com¬ menced painting between 9 and 10, worked 4 or 5 hours, and then gave up the rest of the day to visits and enjoyment. He died in 1788, in the 61st year of his age, and was buried in Kew churchyard. Gal, in Cornish, rusty iron ore. Galena, ore of silver and lead, after the silver is extracted. Galilee, a porch or chapel at the en¬ trance of a church. The galilee at Lincoln cathedral is a porch on the west side of the south transept: at Ely cathedral it is a porch at the west end of the nave : at Durham it is a large chapel at the west end of the nave, which was built for the use of the women, who were not allowed to advance further into the church than the second pillar of the nave. Gallery, an apartment generally of greater length in proportion to the width, applied for the purpose of exhibiting pictures or sculpture: used formerly in early English Do¬ mestic architecture, in large houses, as a place of resort for dancing and other amusements. Galliot, a Dutch vessel, carrying a main and a mizen mast, and a large gaff main-sail. Gall-stone (colour), an animal cal¬ culus formed in the gall-bladder, principally of oxen. This concre¬ tion varies a little in colour, but is in general of a beautiful golden yellow, more powerful than gam¬ boge, and is highly reputed as a water-colour: nevertheless, its co¬ lour is soon changed and destroyed by strong light, though not subject to alteration by impure air. Galvanism comprises all those elec¬ trical phenomena arising from the chemical agency of certain metals with different fluids. Galvanometer, an instrument con¬ trived to measure minute quanti¬ ties of electricity. Gamboge, or, as it is variously written, Gumboge, Gambouge, Cambogia, Gambadium, etc., is brought from Cambaja, in India, and is the pro¬ duce of several kinds of trees. It is, however, principally obtained from the tree called Gokathu,which grows in Ceylon and Siam. From the wounded leaves and young shoots the gamboge is collected in a liquid state, and dried. Gam¬ boge is a concrete vegetable sub¬ stance, of a gum-resinous nature, and beautiful yellow colour, bright 205 GARDENS. GAM and transparent, but not of a great depth. When properly used, it is more durable than generally re¬ puted, both in water and oil, and conduces, when mixed with other colours, to their stability and dura¬ bility, by means of its gum and resin. It is deepened in some de¬ gree by ammoniacal and impure air, and somewhat weakened, but not easily discoloured, by the ac¬ tion of light. Gammoning, in navigation, seven or eight turns of a rope passed over the bowsprit, and through a large hole in the stem or knee of the head, alternately, and serving to bind the inner quarter of the bow¬ sprit close down to the ship’s stem, in order to enable it the better to support the stays of the fore-mast: after all the turns are drawn as firm as possible, the opposite ones are braced together under the bow¬ sprit by a trapping. Gammoning hole, a hole cut through the knee of the head, and some¬ times one under the standard in the head, for the use of gammon¬ ing the bowsprit. Gurboard stroke, the strake in the bottom that is wrought into the rabbet of the keel of a ship. Gardens. The ancient plans of gar¬ dens show that the Egyptians were not less fond than our ancestors of mathematical figures, of straight walks, architectural decorations, and vegetable avenues; and that they as thoroughly entered into the idea of seclusion and safety suggested by enclosures within en¬ closures. It has been remarked, that in some old English places there were almost as many walled compartments without as apart¬ ments within doors : the same may be said of Egyptian country-houses. This principle of seclusion and an excessive love of uniform arrange¬ ment are remarkably displayed in the plan of a large square garden given in Professor Rosellini’s great work. GAS As a subject for the painter, the materials which form the scenery of a garden are provided by Nature herself: the artist must therefore be satisfied with the degree of ex¬ pression which she has bestowed, and give the best possible disposi¬ tion to those scanty and intractable materials. In a landscape, on the contrary, the painter has the choice of the objects he intends to repre¬ sent, and can give whatever force or extent he pleases to the expres¬ sion he wishes to convey, as the whole range of scenery is before his eye. Gargoyle or Gurgoyle, a projecting spout used in Gothic architecture, to throw the water from the gutter of a building off the wall. Garland, an ornamental band used in Gothic work. Garnet, a hinge, now called a ‘ cross garneta red gem of various sizes. Garret, an upper apartment of a house, immediately under the roof. Garrett.ing, small splinters of stone inserted in the joints of coarse masonry: they are stuck in after the work is built: flint walls are very frequently garretted. Gas. All substances,whether animal, vegetable, or mineral, consisting of carbon, hydrogen, and oxygen, when exposed to a red heat, pro¬ duce various inflammable elastic fluids capable of furnishing artificial light. The evolution of this elastic fluid may be perceived during the combustion of coal in a common fire. The coal, when heated to a certain degree, swells and kindles, and frequently emits remarkably bright streams of flame, and after a certain period these appearances cease, and the coal glows with a red light. The flame produced from coal, oil, wax, tallow, or other bodies which are composed of carbon and hydrogen, proceeds from the pro¬ duction of carburetted hydrogen gas, evolved from the combustible body when in an ignited state. 20G lS GAS. If coal, instead of being burnt in the ordinary way, be submitted to the temperature of ignition in close vessels, all its immediate con¬ stituent parts may be collected : the bituminous part is distilled over, in the form of coal-tar, etc., and a large quantity of an aqueous fluid is disengaged at the same time, mixed with a portion of es¬ sential oil and various ammoniacal salts. A large quantity of carbu- retted hydrogen, carbonic oxide, carbonic acid, and sulphuretted hydrogen, also make their appear¬ ance, together with small quantities of cyanogen, nitrogen, aiid free hydrogen, and the fixed base of the coal alone remains behind in the distillatory apparatus, in the form of a carbonaceous substance called colce. An analysis of the coal is effected by the process of destruc¬ tive distillation ; and the products which the coal furnishes may be separately collected in different vessels. The carburetted hydrogen, or coal-gas, when freed from the ob¬ noxious foreign gases, may be pro¬ pelled in streams out of small aper¬ tures, which, when lighted, form jets of flame, now called gas-lights. Mr. Croll has patented an in¬ vention for the purification of gas from ammonia, which is effected by means of dilute sulphuric acid applied between the condensers and the ordinary lime purifiers. The vessels are made either of wood or iron, and lined with lead, having a wash-plate similar to the wet-lime purifiers. The radiating bottom is formed of wooden bars, for the pur¬ pose of supporting the wash-plate and distributing the gas. In com¬ mencing the process, these vessels are charged with water and sulphu¬ ric acid in the proportion of 7 lbs. of the latter to 100 gallons of the former. As the acid is neutralized by the ammonia contained in the gas passing through the vessels, the above proportion is kept up by GAS a continuous dropping or running of acid, regulated according to tbe quantity of ammonia contained in the gas, from a reservoir placed on the top of the saturator. This mode of supplying the acid is con¬ tinued until tbe specific gravity of the solution is at 1170, or near the point of crystallization ; after which the supply of acid is discontinued, and the liquor retained in the vessel until neutralized : it is then drawn off and evaporated, and yields a pure sulphate of ammonia. Gas (distribution of, through mains). There is no branch of science con¬ nected with the subject of gas en¬ gineering so highly important as that which relates to its conveyance and distribution through pipes; there is none in which theory af¬ fords more assistance, and there is hardly any branch to which so lit¬ tle attention has been paid. The interests of a gas company are not best served by simply increasing the quantity of gas from the same quantity of coal, or improving the lime machinery, etc. The laying of street-mains forms the most consi¬ derable item in the outlay; and by a judicious arrangement in the first instance, much may be saved both at first and last. It is for the purpose of rendering this branch of the science, and that of the passage of gas through pipes, perfectly plain, that the following observations are here given. When it is proposed to light any town, or district of a town, with gas, the first step to be taken is to ascertain the number of lights, both public and private, that will be required, with as much accu¬ racy as circumstances will permit; the lenglh of time such lights will have to burn, and the quantity of gas consumed by them per hour, making allowances for the increase of lamps that will probably be re¬ quired by the extension of the town. The size of the works themselves may be easily ascertained from this 207 GAS GASOMETER. GAS calculation. It will then remain Supposing a district to be lighted to fix upon a proper situation in requiring 1000 public or street which to erect them : the best local lamps, and 7000 private burners, position is upon the banks of a na- it is usually considered that each vigable river or canal, and at the lamp on an average will consume lowest available level, and the near- 5 cubic feet of gas per hour, there- est approach to such a situation is fore 40,000 cubic feet will be re- advisable for obvious reasons. A quired to light the district for an map of the town must be obtained, hour ; and the leading main must or a survey made of the different be capable of delivering that quan- streets and thoroughfares: running tity into the equilibrium cylinder levels must be taken through them in that time. To determine the at several points, and their respec- size of this main, the probable in- tive heights marked with reference crease of lamps must be taken into to the level of the works as a da- consideration ; and as that will de- turn : upon this map all the mains pend so much upon circumstances must be drawn, also their branches, in every instance, the judgment of valves, and governors. Their ar- the engineer alone can serve to re- rangement must be such as to allow gulate the additional area. If the of a perfect circulation of the gas, increase should be beyond that and a nearly uniform pressure at which was expected, the gas must U the highest and lowest point. All be forced through the leading main { the pipes upon the same level at a greater pressure. should be joined into one another, In the above example, if the and no valves used but such as are diameter of main for a present con- necessary to shut off the gas for sumption be 12 inches, and to se- repair of mains. To supply a higher cure an adequate supply at any level, a governor should be placed future period its diameter be in- at the summit of the lower level, creased to 15 inches, th e. present with the lower main leading into working pressure may be reduced it. The pipe or pipes for supplying to l - 5ofan inch instead of 3 inches; the higher parts should proceed and as the leakage will also be from the regulating vessel. A cel- decreased, the extra-sized main lar may be appropriated for the will not be found disadvantageous reception of this vessel. One lead- even in the first instance. ing main should be taken direct Gasometer, a reservoir of gas, with from the works to an equilibrium conveniences for measuring its cylinder situated at some point volume. The simplest aud most from which several streets diverge, general in use consists of an iron and no supply taken from this main vessel, open at the bottom, and until it has reached the cylinder. inverted into a tank of water below Branches suitable to the supply the surface of the ground, having 4 of each division of the district perfect freedom to rise and fall, should lead from this cylinder. and guided by upright rods fixed at [ The supply of gas to the cylinder several points in the circumference. should be so regulated as to cause The diameters and numbers of the the gas to flow along the branches vessels will vary according to the at an even pressure of about five- magnitude of the works to which tenths of an inch. If the cylinder the gasometer is attached, and the be at any considerable distance space to be occupied by it. If the from the works, a smaller main, works are situated in a town, where with increased pressure, may lead the ground is too valuable to allow to it, its size being sufficient to an increased extent, a ‘telescope equalize the discharge. gasometer’ is employed. 208 GAS GATES AND DOORS. GAU Gas-tar, commonly called coal-tar. When the manufacture of gas from coal was in its infancy, great advantages were expected to be derived from the coal-tar which distilled over with the inflammable gas. It was considered to be a substance possessing even superior properties to the vegetable tar for the preservation of timber and other perishable materials exposed to the influences of the weather. In the year 1665 a German chemist proposed to distil coal for the sole purpose of obtaining this tar, and in 1781 the Earl of Dun- donald took out a patent for col¬ lecting the tar which appeared during the formation of coke. Nei¬ ther scheme answered. After a few years’ trial, coal-tar as a sub¬ stitute for vegetable tar fell into disuse. It was tried in the navy, and was found to give the timber a considerable degree of hardness, but not of durability. Its smell is extremely offensive; and since that time it has been used only in places where that is of little conse¬ quence. The exposed part of the machinery of a gas establishment may be protected by being coated with coal-tar. Gasket, plaited cord fastened to the sail-yards of a ship, and used to furl or tie up a sail firmly to the yard, by wrapping it round both six or seven times, the turns being at a competent distance from each other. Gatchers, the after-leavings of tin. Gate-house, or park entrance, a struc¬ ture designed rather to produce an agreeable and picturesque effect, than to accord with any fixed rules or customs of art: such, indeed, was the practice towards the latter end of the sixteenth century, when it would appear, that most men wished to display their taste and learning in architecture. The gate¬ house also forms an entrance to a private mansion, to any public, municipal, or collegiate building, or to a palace, etc. In the early English architecture, gate-houses, now sometimes called Lodges, were large and imposing structures, of great elegance. Gates and doors are generally, whe¬ ther arched or square, twice their breadth in height. The former may be ornamented with columns, pilasters, entablatures, pediments, rustics, imposts, archivolts, etc.; the latter with architraves round the sides and top of the opening, and crowned with a frieze and cor¬ nice. The cornice in this case is very frequently supported with a console on each side. Columns, pilasters, and other ornaments are also sometimes employed in the decoration of doors. Inside doors should not be nar¬ rower than 2 feet 9 inches, nor is it needful that they exceed 6 feet in height; entrance doors, 3 feet 6 inches to 6 feet 6 inches broad in private dwellings: but in public buildings, where crowds assemble, they must be considerably enlarged. The smallest width for agate should be 8 feet 6 inches. As some general rule for the pro¬ portion of the architraves of com¬ mon dressings to doors may be useful, the following directions may be safely followed : Supposing the height of the aperture to represent the height of a column ; then, if an architrave, frieze, and cornice, or the first only, be desired, take them in the proportion that would Serve for the order itself, and return the architrave down the sides of the door. The whole entablature over a square-headed door should never exceed one-third the height of such aperture. Gauge (pronounced gage), a measure by which the capacity or contents of a cask or vessel may be ascer¬ tained. Gauging is a term used in mensuration, and applied by engi¬ neers in their several operations. The gauge, as applied to railways, became a familiar term during the 209 GERMAN SCHOOL OF PAINTING. GAU antagonistic discussions respecting the proper distance between the lines of rail; and the battle of the gauges, which raged fiercely and ex¬ pensively, ended, like many similar contentions, in both parties spend¬ ing enormous sums of money, with¬ out the result of victory on either side. Gauge, a mixture of fine stuff and plaster, or putty and plaster, or coarse stuff and plaster; used in finishing the best ceilings and for mouldings, and sometimes for set¬ ting walls. Gauge-cocks, two or three small cocks fixed infront of theboilerof a steam- engine, for the purpose of ascer¬ taining the height of the water. Gauge-glass, in locomotive engines, a strong glass tube, connected with the boiler by two cocks attached to the gauge-cock pedestal. The water is admitted to this tube by the lower cock, the steam by the upper cock. It thus becomes an index to what is going on inside the boiler, exhibiting the height or agitation of the water in it. A small cock is placed below the glass for blowing out any sediment which may be deposited in it. Gauge-lamp, in locomotive engines, a small lamp placed beside the gauge-glass at night, that the state of the water in the boiler may be seen by the engine-man. Gauntlet, in heraldry, an iron glove : in challenges, the gauntlet was thrown down in defiance. Gear, furniture, dress, harness: the term is also applied to the several working parts of a locomotive steam-engine. Generating surface, the heating sur¬ face of a boiler, or that on which heat is applied to generate steam. Gentese, in early English architecture, cusps or featherings in the arch of a doorway. Geodesy, the art of measuring and surveying of land. Geometry, the science of quantity, extension, or magnitude. GEO Geoscopy, a knowledge of the diffe¬ rent kinds of earth. German School of Painting. In early times, a school of painting can hardly be said to have existed in Germany : it was merely a suc¬ cession of single artists, who de¬ rived their manner from different sources of originality and imitation. There were some German painters of eminence when the art, emerg¬ ing from its barbarous state, first began to he cultivated in Europe; but as they were totally unac¬ quainted with the ancients, and had scarcely access to the works of their contemporaries in Italy, they copied Nature alone, with the exception of somewhat of that stiffness which forms the Gothic manner. This is by no means the case with their successors, some of whom were edu¬ cated in Flanders, and others in Italy. But if Mengs or Dietrich were comprehended in this school, there would be nothing peculiar to its manner discovered in their works. Albert Diirer was the first German who corrected the bad taste of his countrymen: he ex¬ celled in engraving as well as in painting; his genius was fertile, his compositions varied, his thoughts ingenious, and his colours brilliant. His works, though numerous, were finished with great exactness. For an account of this great man and his productions, see the ‘ Works of Divers Ancient Masters,’ in two vols. folio, 1846. Qeology (a treatise or discourse on the earth) “ is a term which admits of a very wide interpretation, and naturally suggests to the mind in¬ quiries,—1st, into the formation and original condition of the earth; 2ndly, into the successive modifica¬ tions which it has undergone, and the agencies by which they have been effected ; and 3rdly, into its present condition, and the agencies by which changes in that condition aie still effected. The first object of the geologist is to establish, on 210 GIB GIRDERS. GIR the principles of inductive reason¬ ing, the science as it depends on each of these inquiries, and then to apply it to the practical purposes of life. It may be premised that a science is practicably valuable just in proportion as its facts have been discovered, and its laws established and studied ; for so long as we are uncertain whether a known result has proceeded from a definite cause, we are unable apply the fact or circumstance to the elucidation of other facts or circumstances; and so long as we are unacquainted with the properties of any sub¬ stance under our examination, we cannot declare with certainty what share it may have had in the phe¬ nomena we have observed. This may be illustrated by a reference to gunpowder. Its explosive qua¬ lity is the result of its composition, and we can only depend upon the results when we know that the compound has been accurately formed: to ensure, therefore, cer¬ tainty in the operations depending on it, we must take care that a proper standard of composition has been adhered to. In a similar man¬ ner we can only apply geology as a practical science when we have as¬ certained and made ourselves fami¬ liar with those facts which prove the first principles on which it has been founded to be correct and stable.” See Col. Portlock’s work in the Rudimentary Series, vol. 3. Gib and hey, the fixed wedge and the driving wedge for tightening the strap which holds the brasses at the end of a connecting-rod in steam machinery. Gibbons (Grinling), the great carver. The time and place of his birth are unknown : he died 1721. Gimlet, a piece of steel of a cylin¬ drical form, having a transverse handle at the upper end, and at the other, a worm or screw, and a cy- lindric cavity, called the cup, above the screw, forming, in its trans¬ verse section, a crescent. Its use is to bore small holes: the screw draws it forward in the wood, in the act of boring, while it is turned round by the handle : the angle formed by the exterior and interior cylinders cuts the fibres across, and the cup contains the core of wood so cut: the gimlet is turned round by the application of the fingers, on alternate sides of the wooden lever at the top. Gin, a machine, a pump worked by wheels. Giocondo (John) was born at Verona. About the middle of the 15th cen¬ tury he became a Dominican, and acquired great reputation in the sciences, the arts, the knowledge of ancient monuments and archi¬ tecture. He was called into France by Louis XII., and constructed at Paris the Pont-au-Change and the Pont St. Michel. He also con¬ structed other important works in Italy and other countries. He died at an advanced age in 1530. Giotto built the exquisitely slender tower of Florence in the 13th cen¬ tury in emulation of the stupendous spires which at that era were erected in Germany and the Low Countries. In Italy not a single spire is now seen. Giotto of the Florentine School. Painting in his hands became so elegant, that none of his school nor of any other, till the time of Ma¬ saccio, surpassed or even equalled him, at least in gracefulness of manner. Giotto was born in the country, and was bred a shepherd. Girders, the longitudinal beams in a floor. Girders are the chief sup¬ port of a framed floor : their depth is often limited by the size of the timber, but not always so ; there¬ fore the method of finding the scant¬ ling may be divided into more than in one case. Girders of wrought and cast iron are now extensively used in the construction of bridges, to girt railroads, canals, etc., and many of them are of considerable span. 211 GLASS. GLUE GLA Gland, the pressing piece of a stuffing- box of a steam-engine. Glass, an artificial transparent sub¬ stance, the accidental discovery of which, whether by the Phoenicians, as described by Pliny, or not, be¬ longs to the early ages of civiliza¬ tion, and the art of making which, we learn from Venerable Bede’s life of Benedict Biscop, Abbot of AVearmouth, was introduced into Britain as early as a.d. 670, by that nobleman and ecclesiastic on the return from one of his journeys to Borne, where he had been to purchase books and pictures for his church, at which time he was ac¬ companied by John, the Arch¬ chanter of St. Peter’s, who intro¬ duced the Roman method of chant¬ ing into the service of the Anglo- Saxon Church. The use of glass in our windows instead of the louvre-boards of our ancestors, has introduced comfort into the meanest dwelling which pre¬ viously did not belong to the richest palace. By means of this contrivance the light is filtered from the wind, the rain, and the cold ; we can enjoy the one with¬ out being inconvenienced by the others; and we can, in conjunction with our methods of warming, create an in-door climate adapted to our feelings and desires. The use of glass in many of our domes¬ tic articles of furniture and vessels contributes to cleanliness and health, for the slightest soil on our glasses and decanters is revealed by this most transparent material, and the purity of the water and other liquids contained in them is physically tested by the same means. Even the mirror, which adorns our rooms, reminds us of the necessary attention to personal appearance, which self-respect as well as respect for society demands. By means of glass the eye of ad¬ vancing age regains something of its youthful vigour. By means of glass the astronomer makes us ac¬ quainted with distant spheres, and the naturalist with the inhabitants of a drop of water. By means of glass the natural philosopher has discovered the physical marvels of the atmosphere ; and the chemist, its equally wonderful chemical properties. Glasses superseded small drinking- bowls ; they were of Venetian manufacture, and probably first brought here in the 16th century. Earlier they do not appear to have ; been used in England; nor to have ' come into much fashion till the time of Elizabeth. Glass ivater-yauge. See Gauge-glass, j Glazing, the art of fixing glass to the sashes of windows, casements, etc., for the purpose of admitting the j light of day; anciently applied ( to the affixing to windows deco¬ rative, stained, and painted glass. A great many beautiful examples exist, in this and other countries, of early designs, and of examples j in the cinque-cento style: for the latter, see ‘ Divers Works of Early Masters,’ 2 vols. folio, 1846. Glazing is also a term applied to the finishing of a drawing with some ! thin, transparent, and glossy tint, through which the first colours appear, and are heightened in their effect. Glebe, turf, soil; land possessed as i part of the revenue of an ecclesias¬ tical benefice. Glist, a shining black or brown mineral, of an iron cast. Glossoconion, a machine composed of j several dented wheels with pinions, and used for raising great weights. Glue, a tenacious viscid matter, which is used as a cement by carpenters, j joiners, etc. Glues are found to differ very much from each other I in their consistence, colour, taste, j smell, and solubility. Some will f dissolve in cold water, by agitation; while others are soluble only at the point of ebullition. The best glue is generally admitted to be trans- j j parent, and of a brown-yellow co- I { 212 GOTHIC ARCHITECTURE. GLY lour, without either taste or smell. It is perfectly soluble in water, forming a viscous fluid, which w'hen dry preserves both its tenacity and transparency in every part, and has solidity, colour, and viscidity, in proportion to the age and the strength of the animal from which it is produced. To distinguish good glue from bad, it is necessary to hold it between the eye and the light; and if it appears of a strong dark brown colour, and free from cloudy or black spots, it may be pronounced to be good. The best glue may likewise be known by immersing it in cold water for three or four days, and if it swells powerfully without melting, and afterwards regains its former di¬ mensions and properties by being dried, the article is of the best quality. A small portion of finely levi¬ gated chalk is sometimes added to the common solution of glue in water, to strengthen it and fit it for standing the weather. A glue that will resist both fire and water may be prepared by mixing a handful of quicklime with four ounces of linseed-oil, thorough¬ ly levigated, and then boiled to a good thickness, and kept in the shade, on tin plates, to dry. It may be rendered fit for use by boiling it over a fire in the ordi¬ nary manner. Glyphs, perpendicular flutings or channels used in the Doric frieze. Gnomon, in dialling,is the style, pin, or cock of a dial, the shadow whereof points out the hours. Gobbets, stones ; a measure or quan¬ tity, so called in the time of Edward III. I Gola, the Italian term for cyma. Gold, a well-known valuable metal found in many parts of the world, but the greatest quantity was for¬ merly obtained from the coast of [ Guinea. The produce of California 1 remains to be determined. Gold seems to be the most simple of all GOT substances. It is spoken of in Scripture, and the use of it among the ancient Hebrews, in its native and mixed state, and for the same purposes as at present, was very common. The ark of the covenant was overlaid with pure gold; the mercy-seat, the vessels and utensils belonging to the tabernacle, and those also of the House of the Lord, as well as the drinking- vessels of Solomon, were formed of this metal. Gold occurs, in the metallic state, mixed with several metals, but more commonly with silver and copper, and sometimes pure. Golden sulphur of antimony, golden yellow, is the hydro-sulphuret of antimony, of an orange colour, which is destroyed by the action of strong light. It is a bad drier in oil, injurious to many colours, and in no respect an eligible pigment either in oil or water. Gold purple, or Cassius's purple preci¬ pitate, the compound oxide which is precipitated upon mixing the solutions of gold and tin. It is not a bright, but a rich and powerful colour, of great durability, varying in degrees of transparency, and in hue from deep crimson to a murrey or dark purple: it is principally used in miniature painting, and may well be employed in enamel painting. Gondola, a Venetian barge much or¬ namented, used in the canals of Venice for the convenience of the inhabitants: the common dimen¬ sions are 30 feet by 4 feet: each end is terminated by a very sharp point, which is raised perpendicu¬ larly to the full height of a man. Goniometer, an instrument for mea¬ suring angles and crystals. Gossan, an imperfect iron ore, com¬ monly of a tender rotten substance, and of a red or rusty iron colour. Gothic Architecture, usually so called. Both Mr. Britton and Mr. Pugin have treated of it by the name of ‘Christian Architecture.’ It had 213 GOU GOVERNOR. GRA its rise from the Romanesque: this took its origin from Roman remains at the declension of that empire. It became Saxon, then Norman, and varied in its character with the maturity of years. It was Early English, Perpendicular, Decorated, Flamboyant, etc., till it lost its ec¬ clesiastical and monastic character in the Domestic, which prevailed in the Tudor style (Renaissance), followed by the Elizabethan, etc. Gouge , in carpentry, an instrument like a round hollow chisel. Governor, the apparatus for regulating the supply of steam to the cylinder so as to give a constant velocity to the engine. It consists of two balls suspended from a vertical spindle, and revolving with it: the suspend¬ ing rods are connected by arms to a sliding-piece which fits the spindle and acts upon a lever attached to a throttle-valve in the steam-pipe: the balls rise by the centrifugal force as the velocity increases, and close the valve: when the velocity diminishes, the balls fall, and open the valve. Governor, a contrivance for equalizing the motion of mills and machinery, as well as being used as above de¬ scribed. Governor balls, the solid metal balls fixed on the ends of the suspending •rods of the governor. Governor (gas). The governor is a machine for regulating and equal¬ izing the flow of gas from the gaso¬ meters to the street-mains, and is much more perfect in its action than any slide-valve applied for that purpose requiring attendance. Its use is nowhere sufficiently ap¬ preciated. Had it been a com¬ plicated piece of machinery, or expensive in its first cost and after¬ application, objections to its adop¬ tion would not have been surprising, —but it is perfectly simple, its ac¬ tion is certain and unvarying, and its first cost inconsiderable. The velocity of gas in the mains and pipes of supply is,'in the first instance, as various as there are differences in their altitudes and extent. A main at one place wdll furnish, with a certain pressure of gas, a flame one inch high; while ata different altitude it will furnish a flame double that height. If, again, in the direction of the main there are many bends, angles, or contractions in its diameter, the velocity of the gas through it will vary considerably more than if it were direct and uniform. If the pipe be of any great length, and of uniform bore, but unequally fur¬ nished with branches, the burners will be unequally supplied with gas: those which are near its head will be supplied with a fuller stream of gas than those which are situated towards its termination. There will always be one great variation in the velocity of the gas, occa¬ sioned by the variety of periods during which lights are required by different consumers supplied from the same main or system of pipes: for example, when a certain number of burners is to be supplied, and it happens that one-half are shut off sooner than the rest, the velocity of the gas in the mains will be | materially increased, and the re¬ maining lamps should be turned down : but many would not be re- i duced, and much gas would be lost. Gowan, decomposed granite: but the t term is sometimes applied to the solid rock. Gozzan, oxide of iron and quartz. Grace is taken for beauty, graceful form, or agreeableness of person ; for form, friendship, and kindness; for certain gifts of God, which He^ bestows freely, when, where, and| on whom He pleases: such are the gifts of miracles, prophecy, lan¬ guage, etc. Gradient, a deviation from a Ieve- surface to an inclined plane. Graduation, the division of philo¬ sophical instruments into degree: and other minute parts. Grain tin, the finest tin, smelted will 214 GRA GRAVITY. GRE charcoal; also the ore of very rich tin sometimes found in the form of grains or pebbles. Grange, a monastic farming establish¬ ment: in ancient times it was com¬ mon to attach farm-houses and granaries to the estates of religious institutions. Granite, a natural stone of great strength, hardness, and durability ; much used in building: it is a primary and unstratified rock, con¬ sisting of quartz, mica, and felspar, each crystallized and cohering, but without any base or cement. Grapnel, in navigation, a sort of small anchor with four or five flukes or claws, commonly used for boats and small vessels. Graunge or Grange, a granary or farm belonging to a religious house. {Chaucer.) Gravel, a geological term applied to those sabulous soils, or assemblages of worn and rounded stones, which are found scattered on the surface of the earth. Graver, the burin of an engraver; a square piece of steel fixed in a handle, and bevelled diagonally at the end : an instrument used for turning iron, after it has been roughed out by the ‘ heel tool,’ is so called. Gravity is that power or force which causes bodies to approach each other. This universal principle, which pervades the whole system of nature, may be enunciated as follows: the mutual tendency of two bodies towards each other in¬ creases in the same proportion as their masses are increased, and the square of their distance is decreased; and it decreases in proportion as their masses are deci'eased, and as the square of their distance is in¬ creased. j Gravity is also the force wherewith a body endeavours to descend to¬ wards the centre of the earth : this is called absolute gravity when the body tends downwards in free space, and relative gravity is the force it endeavours to descend with in a fluid. Terrestrial gravity is that force by which bodies are urged towards the centre of the earth, and it is measured by the velocity generated in a second of time. Ex¬ periments show that a falling body describes 16 T V feet in one second, and it has then acquired a velocity of 32i feet, which is therefore the true measure of the force of gravity. Gray colour is the third and last, being the nearest in relation of co¬ lour to black. In its common ac¬ ceptation, gray denotes a class of cool cinerous colours, faint in hue; whence we have blue-gravs, olive- grays, green-grays, purple-gravs, and grays of all hues, in which blue predominates ; but no yellow' or red grays, the predominance of such hues carrying the compounds into the classes of brown and mor- rone. Graywacke, a coarse slate; in geo¬ logy, a secondary rock. Grease-cock, a short pipe fixed in the cylinder cover of a steam-engine, with two stop-cocks inserted at a short distance apart, and a funnel at the top for holding tallow. When the upper cock is opened, the tallow falls into the intermediate space ; the cock is then closed, and the lower one opened for the melted grease to enter the cylinder, and lubricate the piston without allow¬ ing the steam to escape. , Great Circle sailing, the steering of a ship in the arch of a great circle of the sphere. The nearest course between two places. Green Cloth, the compting-house of the Kings’ households. Greenhouse, a garden-house for choice flowers, etc. Greenverditer is thesame in substance as blue verditer, which is converted into green by boiling it. Green ebony wood, imported from the West Indies, is us.ed for round rulers, turnery, marquetry-work, etc.; it is also much used for dyeing, and contains resinous matter. 215 GREGORIAN CHANT. GRE GREGORIA N CHANT. GRE Greenheart wood, from the West In¬ dies, resembles cocoa wood in size and bark, and is used for turnery and other works. Grees, steps; also a staircase. Gregorian Chant: Cantus Gregoria- nus, Cantus Firmus, Cantus Planus or Plenus, in Latin; Canto Firmo, in Italian ; Plein Chant, in French ; Plain Chant,in English; and Choral, in German. This species of music is the most ancient of all, and is still the only one properly adapted to the ritual services of the Chris¬ tian churches. The Gregorian chant consists of a few notes, on which the words of the Liturgies are recited. The earliest specimens in existence con¬ sist of only one or two notes, and ■were used by St. Ambrose, at Milan, in the fourth century. The origin of this chant is traced to the earlier churches of Egypt, Thebes, Pales¬ tine, Arabia, Phoenicia, Syria, etc., from whence it was introduced into the church of Constantinople by St. John Chrysostom. St. Ambrose is said to have brought it into use in Milan, “ after the custom of the inhabitants of the East,” and from Milan it came to Rome “ long be¬ fore the time of St. Gregory.” But as, in thef course of time, various mutations had taken place, St. Gre¬ gory, in order to reform and settle the music for the church, made a compilation of such as was fit for its use, and formed the first ritual book of music, or Roman Anti- phonarium. From the order which he gave it, and in consequence of this work of Gregory being after¬ wards established in the other (the Western) churches, it received the name Gregorian. We have very little of the music ascribed to Gre¬ gory himself, a specimen of which is given by Mr. Spencer in his work on the church modes, and is very grand. A portion of the old Gre¬ gorian chant is still used in our cathedrals in the so-called ‘ into¬ ning the service’ by the minor canons and also in the responses by the choir, but in a very mutilated form. But in the chanting of the prose Psalms, it is almost entirely abandoned ; the only specimen (and that somewhat mutilated) being the grand and well-known ‘ Tallis’s chant.’ There is a remarkable difference between the Gregorian melodies for the Psalter and Can¬ ticles (and which are called the eight tones) and those of a more modern date. No such thing as a double chant exists in Gregorian music, and the ‘ tones ’ are formed on one general law; i. e. a ‘ tone ’ consists of one principal note, called the Dominant, i.e. the predominant or reciting note, upon which the principal part of each half-verse is chanted, the remainder being in¬ flected in cadences of one or several notes revolving (as it were) above j and below the dominant, or ter- 1 minating on the final of the mode ; | and it is a law that the reciting ; parts are always (when the tone is regular) on the same note, viz. the dominant. There are very few ■ instances of any deviation from ; this rule. In the modern system there seems to be a total absence of any rule of this sort, and the cadences, both in the middle of the ! verse and at the end, consist of a greater number of notes, and these t of unequal value. Moreover, in the Gregorian chant no attention is paid to time; it is regulated entirely by emphasis and syllabic quantity, not by time and accent, as in mo- i dern chanting. On Sundays and the greater festivals it is a rule to commence the ‘tone’with a few preliminary notes, called the into¬ nation, which serve as in inchoa- tion, or induction to the dominant, or reciting note: on other occa¬ sions, these initial notes are not used. For specimens of the adap¬ tation of these Gregorian tones or chants to the canticles, etc., of the ' English church, see the ‘ Hymnal,’ by Mr. Spencer. 216 GROINS. GRE Gregorian music requires a no¬ bler and more rigid harmony than can be given in the modern system ; and its effects in the divine offices, when properly harmonized and performed, are far superior to any other kind of church music. Greut, or Grit, a kind of fossil body, consisting of sandy, rough, hard, earthy particles. Grey. See Gray. Griddle, a large wire sieve, used in¬ stead of a hurdle, for sifting and sorting copper ore as it rises from the mine. Grbnbald, an architect, supposed to have introduced the style of ar¬ chitecture usually called Saxon into England. Grindstone, a cylindrical stone, on which, being turned round its axis, edge-tools are sharpened by apply¬ ing their edges to the convex sur¬ face. Gripe, the lower part of the knee of the head that connects with the foremost end of the keel of a vessel. Grit, coarse sand ; rough hard par¬ ticles of sandstone. Groin, the angle formed by an inter¬ section of vaults : most of the vaulted ceilings of the buildings of the middle ages were groined, and therefore called groined ceilings. During the early part of the Nor¬ man style the groins were left pur¬ posely plain, but afterwards they were invariably covered with ribs. Groins, in coast engineering. A groin is a frame of wood-work, con¬ structed across a beach, between high and low water, perpendicular to the general line of it, either to retain the shingle already accumu¬ lated, to recover it when lost, or to accumulate more at any particular point; also to break and check the action of the waves. The component parts of a groin are piles, planking, land-ties, land tie-bars, blocks, tail-piles, and keys and screw-bolts. The length of a groin depends on the extent, and the requisite GRO strength of its component parts on the nature of the beach on which it is to be constructed. Those at Eastbourne, on the coast of Sussex, of which the following is more particularly a description, are from 150 to 250 feet in length, and the beach at that place being very rough, consisting of coarse heavy shingle and large boulders, they require to be composed of propor¬ tionally strong materials to resist its force. The piles are from 12 to 25 feet long, and 8 by 6^ inches scantling, shod with iron. The planking is in lengths of 8, 12, and 16 feet, 2^ inches thick, and with parallel edges. The land-ties are of rough timber from 20 to 25 feet long, and large enough at the butt-end to receive the bars. The land tie-bars are 13 ft. 6 in. long, and 12 by 5 in. scantling. The land tie-bar blocks are about 2 feet long, and of the same scant¬ ling as the piles. The land-tie tail-keys are about 2 feet 6 inches long, and 6 by 2^ inches scantling. The above materials are of oak or beech. The screw-bolts are of inch round iron, 2 feet 9£ inches and 2 feet l^inch long, in equal proportions. The relative proportions of the component parts are, four piles, one land-tie with tail-piles and keys, one land tie-bar with two blocks, two long and two short bolts, about 180 square feet of planking, and about 140 six-inch spikes for every 17 feet in length; and the expense of a groin, constructed with mate¬ rials of the above dimensions, may be calculated at about £30 for the same length. GENERAL RULES OBSERVED IN THE CONSTRUCTION. When the object, in constructing a groin, is to recover shingle, or accumulate more, the first pile is driven at the high-water mark of 217 GROTESQUE. GRO neap-tides, leaving its top level with that of spring-tides. The next is driven at the point on the sands, beyond the bottom of the shingle, to which the groin is to extend, leaving about 4 feet of it out of the beach. The tops of these two piles may be taken for the general slope of the groin, unless the beach should be very steep, and much curved, in which case it becomes necessary to follow its curvature in some degree. From the high-water mark of neap-tides, the piles are carried back nearly level to that of spring- tides, and as much further as may be considered necessary. The piles are driven 4 feet asun¬ der from centre to centre, and so as to admit the planking between them alternately, and they should be sunk about two-thirds of their length, The longest piles are placed be¬ tween the high-water mark of neap- tides and the bottom of the shingle, particularly from 20 to 40 feet below the former point. The planking is, if possible, car¬ ried down to about two-thirds from the tops of the piles, and kept pa¬ rallel with them. The land-ties are placed about one-third from the top of the plank¬ ing (supposing the latter to com¬ mence from the tops of the piles), and their tails are sunk to the level of the bottom of the planking, or as nearly so as possible. Grotesque. This term, which is now familiar among all the lovers of the art of painting, was by the Italians appropriated to that peculiar man¬ ner of composition and invention observed among the antique mo¬ numental paintings which were discovered in the subterraneous chambers that had been decorated in the times of the ancient Romans; and as the Italians apply the word Grotto to express every kind of cave or grot, all paintings which were in imitation of the antique GUI designs discovered in those cham¬ bers, which for ages had been covered with ruins, are grotesqued or grotesque, which is now applied to English subjects of a quaint and anomalous character. Grotesque , a name given to the light and fanciful ornaments used for¬ merly to characterize persons and things. Grotto , a natural or artificial cavern or cave. Grouan lode, any tin lode which abounds with rough gravel or sand. Ground-plate or ground-sill, the low¬ est plate of a wooden building for supporting the principal and other posts. Grounds, pieces of wood fixed to walls and partitions, with their surfaces flush with the plaster, to which the facings or finishings are attached. Ground table stones, the projecting course of stones in a wall above the plinth. Ground-ways, large pieces of timber laid across a ship or dock, and upon which the blocks are placed. Groundwork, in painting, that colour or part on which all the images are drawn. Grouping is the combining or joining objects in a picture for the satis¬ faction of the eye, and also for its repose ; and although a picture may consist of different groups, yet those groups of objects, managed by the chiaro-oscuro, should all tend to unity, and one only should predominate. Guag, Cornish. Tinners, holeinginto a place which has been wrought before, call it holeing in guag. Gudgeon, the iron pins fixed in a beam or wooden shaft for bearings. ; Gudgeons, in ship-building, are eyes driven into the stern-post, to hang the rudder on. Guide-blocks, pieces of metal with parallel sides, fitted on the ends of a cross-head of a steam-engine, to slide in grooves in the side frames, and keep the motion of the piston- rod in a direct line. 218 GUSSETS. GUI Guilloche, an ornament used in clas¬ sical architecture, formed by two or more intertwining bands. Gulf of ore : a lode which throws up very great quantities of ore, and proves lasting and good in depth, is so called. Gum wood, or blue gum wood, is the produce of New South Wales, sent over in large logs and planks, simi¬ lar to dark Spanish mahogany : it is used in ship-building, etc. Gun-boats were first made in this country with condensing engines, but of late a few have been made with non-condensing or high- pressure engines, which latter kind are found more convenient where fresh supplies of fuel can be rea¬ dily obtained. Gundulf of Rochester, 1077-1107. His works are seen at Rochester, Canterbury, and Peterborough. Gun-metal, a mixed metal, an alloy of copper and tin. Gunnies, in Cornish, a term applied to breadth or width: single gun¬ nies are 3 feet wide. Gunter’s chain, the chain in common use for measuring land : the length of the chain is 66 feet, or 22 yards, or 4 poles of 5| yards each ; it is divided into 100 links of 7'92 inches each. See Acre. Gunwale, ox gunnel, in ship-building, the piece of timber which reaches on either side of the ship from the half-deck to the forecastle.—The plank that covers the heads of the timbers between the fore and main drifts. Gussets, as understood in mechanical construction, are brackets or an¬ gular pieces of iron, to strengthen, to keep steady, and support a structure.—In the construction of- EL Hade of Veins is the mining-term I for that inclination which nearly all veins have from a perpendicular direction. Thus, a vein is said to ] HAL the rectangular covered openings of the Britannia and Conway iron bridges, gussets are used exten¬ sively in the interior, consisting of double triangular plates riveted to the bottom and sides of the plates of the bridge, as a series of brack¬ ets (and at the top and either side also), to aid to the strength and durability of these extraordinary works, and as a counter-effort to the tendency of strain on the lower sides to separate or open the joints, and on the upper side to force them closer together. Gusto, a term used by the Italians, signifying taste in the design of the attitudes, good arrangement, and composition of a picture. Guttce, ornaments resembling drops, placed in the epistylium of the Doric order below the triglyphs. They occur likewise in the under face of the mutules in the Doric corona. They are supposed to have originated from the intention to represent drops of water running off the roof, adhered to the under surface of the canterii or rafters of early buildings. Gybing, in navigation, the shifting of any boom-sail from one side of the mast to the other. Gymnasium, a public building used by the Greeks for the practice and exercise of gymnastics, or mus¬ cular development; also a place, according to Vitruvius, for amuse¬ ments and scientific recreation. Gynoeceum, in Greek architecture, the apartment of the females in the interior of the house ; the nursery. Gypsoplaste, a cast taken in plaster of Paris or white lime. Gypsum, sulphate of lime, called also plaster of Paris. hade to the north when it inclines further north. In Weardale, the veins mostly hade to the south. Half-bloom, a round mass of metal, i. 2 219 HAL HALF-TIMBERED HOUSES. HAR which comes out of the fining of an iron work. Half-pace, or Haute-pace, a raised floor in a bay window. Half-timbered houses : this mode of constructing domestic buildings was practised in England and on the Continent during the reigns of Henry VIII. and Elizabeth. It was peculiarly of a picturesque charac¬ ter; the foundations and principal supports were of stout timber, and the interstices of the fronts were filled with plaster. In many cases the ornamental timber framing w T as of a dark colour, which, with the barge-board gable, gave the whole an exceedingly interesting appear¬ ance. There are yet remaining some very fine examples in England, particularly in the western and north-western counties. Half-timbers, in ship-building, those timbers in the cant-bodies which are answerable to the lower fut- tocks in the square body. Hall, the principal apartment in the domestic houses of the middle ages; a place of assembly; a spacious building attached to inns of court. Halliards, in navigation, the ropes or tackles usually employed to hoist or lower any sail on its respective mast. Haly-work folk, people who hold land for repairing or defending a church or tombs, on which account they were freed from feudal and military service. Ilallyings, the hangings of a hall. Ilalvans, in Cornish, the refuse ore. Ham (Saxon), a house, home, farm, or village. Hamburg lake is a colour of great power and depth; rather purplish, or inclining to crimson : it dries with extreme difficulty, but differs in no other essential quality from other cochineal lakes. Hamlet, a street or village, a dwell¬ ing place. Hammer-beams, horizontal pieces of timber, frequently used in the roofs of old English buildings, in pairs on the opposite sides of the same roof; often used also in the prin¬ cipals of Gothic roofs, to strengthen the framing and to diminish the lateral pressure that falls upon the walls. Hances, in architecture, ends of ellip¬ tical arches, which are arcs of smaller circles than the scheme or middle part of the arch. Hand-brace, a tool for boring, con¬ sisting of a cranked spindle, at one end of which a broad head or breast-plate is attached by a swivel, so that it may remain stationary while the crank is turned; at the other end is a socket, into which a drill can be fixed. Hand-drilling machine, a small drilling machine turned by manual labour. Hand-gear, in a locomotive engine, the handles of the working gear, placed conveniently to the foot¬ plate so as to be within reach of the engine-man when he requires to use them for regulating the dif¬ ferent parts of the engine. Hand-hook, an instrument made by smiths to twist square iron. Hand-pump, in a locomotive engine, the pump placed by the side of the fire-box, to be worked by a hand- lever when the engine has to stand with steam up. Hand-railing, in a locomotive engine, the railing along the sides of the engine, to protect persons passing to the front of the engine for any necessary purpose. Hand-saw, a saw from 12 to 15 inches in length, fixed in an iron frame, with a handle at one end; used for cutting wood or metal. Hand-screw, a jack, an instrument for raising heavy timber. Hand-spike, a wooden lever for mov¬ ing heavy things. Hand-vice, a small vice which is held in the hand. Harbourage, shelter,or entertainment. “ Crave harbourage within *your city walls.”— Shakspeare. Harmony is the general accordance of the objects in a painting with one HAR HEALTH OF TOWNS. HEA another, and their subordination to the principal object; so that all unite to constitute a pleasing whole. It is effected by a due combination of lights and shades, by the union and colour, or by such contrasts as are sufficient to relieve the dis¬ tant groups. Harmony of colours. Lessons in colouring have ever been given,not¬ withstanding it is a part so princi¬ pal in painting, that it has its rules founded on science and reason. Without such study, it is impos¬ sible that youth can acquire a good taste in colouring, or understand harmony. Harpings, pieces of oak which hold the timbers of the fore-and-aft cant-bodies till a ship is planked. Hatches, the coverings for the hatch¬ ways of a ship, made with ledges, and laid with oak or deal, and caulked. Hatches, flood-gates in a river to stop the current of the water. Hatching is shadowing with a black- lead pencil or pen : it is done either in straight lines or zigzag strokes, such as are seen in pencil draw¬ ings, or in pencilled backgrounds. It is used by engravers in etching. Hatchways, places in the middle of the decks of a vessel, for the con¬ venience of lowering down goods. Haul the wind, in navigation, to direct the ship’s course nearer to the point of the compass from which the wind blows. Haunch of an arch, the part between the vertex and the springing. Hawker, a vessel built like a pink, but masted and rigged like a hoy. Haws, in Domesday Book, mansions or dwelling-houses. Hawse, in navigation, the situation of the cables before the ship’s stern when she is moored with two an¬ chors forward from the starboard and larboard bow. Hawse-pieces, the timbers in the bow of a ship whose sides are nearly parallel to the middle line. Hawthorn, a wood not much used, is hard, and of a whitish colour, with a tinge of yellow. Hazel, a small underwood, which is very elastic, used for turning, for the handles of blacksmiths’ chisels, for the hoops of casks, etc. Head-ledges, the thwartship pieces which frame the hatch-ways or ladder-wavs of ships. Head-stocks, the frames which sup¬ port the centres of a lathe; viz. the mandril-frame and the poppet- head, or back centre frame. Head-tin, a preparation of tin-ore to¬ wards the fitting it for working into metal. Headers, in masonry, stones extend¬ ing over the thickness of a wall; and in bricklaying, the bricks which are laid lengthwise across the thick¬ ness of the wall are called headers. Heads, tiles which are laid at the eaves of a house. Healing, the covering a roof with lead, tin, slates, etc. Health of Towns, a phrase recently coined to express the general pur¬ pose of public sanatory measures. These measures are based upon the principles of animal physiology, but had been recognized only in the curative policy of the physician, until the evils of their neglect were traced by statistical inquiries into the causes of disease; and they are therefore now properly regarded as essential objects in the social eco¬ nomy of life. The human constitution is so formed that its health depends on an adequate supply of pure air, water, and light. Every circum¬ stance, therefore, which vitiates the quality, or reduces the due quan¬ tity, of these essentials, is injurious to health, and demands amendment or extinction. Thus the efficient supply of pure and attemperated air requires pro¬ per drainage and ventilation, warm¬ ing or cooling of all places in which human beings live or congregate : it also limits the minimum of size for the healthy habitations of men. 221 _ ; HEA HEAT. HEA The plentiful supply of pure wa¬ ter necessitates suitable provision for obtaining and treating it, and the proscription of all arrangements •which limit the service or injure its purity. Equally important with these conditions is the third one enumerated, which suggests the ne¬ cessity of so arranging and con¬ structing streets and buildings, that abundance of light may at all times be admitted into them. As measures auxiliary to these objects, and of great importance in the combined arrangements of so¬ ciety, public exercising and plea¬ sure grounds, baths and wash¬ houses, cooking apparatus, medical and remedial establishments, street accommodations, etc., command adoption, and, when adequately- carried out, will tend to complete the physical requisites of the health of towns. Heat, in the ordinary application of the word, signifies, or rather im¬ plies, the sensation experienced upon touching a body hotter, or of a higher temperature, than the part or parts which we bring into contact with it; in another sense, it is used to express the cause of that sensation. To avoid any am¬ biguity that may arise from this double use of the same expression, it is usual and proper to employ the word caloric to signify the principle or cause of the sensation of heat. On touching a hot body, caloric passes from it, and excites the feeling of warmth: when we touch a body having a lower tem¬ perature than our hand, caloric passes from the hand to it, and thus arises the sensation of cold. Caloric is usually treated of as if it were a material substance ; but, like light and electricity, its true nature has yet to be determined. COMMUNICATION OP CALORIC. Caloric passes through different bodies with different degrees of ve¬ locity. This has led to the division of bodies into conductors and non¬ conductors of caloric : the former ; includes such bodies as metals, ; which allow caloric to pass freely [ through their substance ; and the I latter comprises those that do not give an easy passage to it, such as stones, glass, wood, charcoal, etc. Table of the relative conducting power of different bodies. Gold . 1000 Platinum . . 981 Silver . 973 Copper . 898 Iron . 374 Zinc . 363 Tin . . 304 Lead . 180 Marble 24 Porcelain . 12-2 Fire-brick 11 Fire-clay . 11*4 With Water as the standard. Water 10 Pine 39 Lime 39 Oak. 33 Elm 32 Ash . 31 Apple 28 Ebony 22 Relative conducting power of dif¬ ferent substances compared with each other. Hares’fur . . 1-315 Eider-down 1-305 Beavers’ fur 1-296 Ravr silk . 1-284 Wool 1-118 Lamp-black 1117 Cotton 1-046 Lint 1032 Charcoal . •937 Ashes (wood) . •927 Sewing silk •917 Air •576 Relative conducting power of fluids. Mercury . 1000 Water •357 Proof Spirit •312 Alcohol (pure) . •232 RADIATION OF CALORIC. When heated bodies are exposed to the air, they lose portions of 222 HEA HEIGHTS AND DISTANCES. HEI their heat, by projection in right lines into space, from all parts of their surface. Bodies which radiate heat best, absorb it best. Radiation is affected by the na¬ ture of the surface of the body: thus black and rough surfaces ra¬ diate and absorb more heat than light and polished surfaces. Table of the radiating poioer of different bodies. Water . , .100 Lamp-black . . 100 Writing-paper . . 100 Glass ... 90 Indian ink . 88 Bright lead . . 19 Silver . . . 12 Blackened tin . . 100 Clean do. . . 12 Scraped do. . . 16 Ice .... 85 Mercury ... 20 Polished iron . . 15 Copper ... 12 Professor Leslie has proved, by a variety of experiments, that the heat which is propagated by radi¬ ation from different bodies varies with the nature of their external surfaces; the quantity which flows in a given time from a body with a polished surface being much less than would flow from the same body with a rough surface. It therefore follows that the external surfaces of the steam-pipes of steam- engines and steam-cylinders should he as smooth as possible, and should be covered with any body which is a bad conductor of heat. Heaven (in the Table of Symbols of the early ages) is symbolized by the segment of a circle, sometimes of blue or of the three colours of the rainbow ; the Universe, by a globe of blue. Heckler (Jean Geo.), born in 1628, became in 1654 architect of the cathedral of Strasburg, and died in 1669. Heel tool, a tool used by turners for roughing out a piece of iron, or turning it to somewhat near the intended size: it has a very acute cutting edge and an angular base or heel. Height of columns. The height of a column is measured by its diameter immediately above the base. Diameters high. The Tuscan column . 7 The Ionic ... 9 Corinthian and Composite 10 In the above heights are included the capitals and bases, which are esteemed parts of the columns with which they are used. Heights and Distances. Trigonometry receives its principal practical ap¬ plication in the operations of sur¬ veying, and measuring heights and distances; as, however,the methods of its application (depending on the peculiar circumstances of each case) are exceedingly various, no general rules can be specified. The instruments employed to measure angles are quadrants, sex¬ tants, theodolites, etc., the use of either of which may be sooner learned from an examination of the instruments themselves than from any description independently of them. For military men and for civil engineers, a good pocket sex¬ tant and an accurate micrometer (such as Cavallo’s), attached to a telescope, are highly useful. For measuring small distances, as bases, 50-feet and 100-feet chains and a portable box of graduated tape will be necessary. For the purposes of surveying, it is usual to employ a chain 66 feet in length, subdivided into 100 links, each 7'92 inches: the reason for using a chain of this length is, that ten of such square chains are equal to an acre, and therefore the acre¬ age of the several divisions of an estate is found with much greater facility when measured in chains and links, than when the measure¬ ments are taken in feet. Heil, to cover, to tile. Wat Tyler was called Wat the Heiler. 223 HERALDRY. HEL Helix, the small volute under the abacus of a Corinthian capital, j Helix, anything of a spiral form, whe¬ ther in one plane,as the spiral curve, or in different planes, as the screw. Hemlock spruce forms a large pro- j portion of the evergreen forests of j New Brunswick, and is abundantly multiplied in every favourable si¬ tuation. The wood of the hemlock [ spruce is firmer than that of the white pine ; although coarser- grained, it gives better hold to nails, and offers more resistance to the impression of other bodies. Hengin, a prison, or house of cor¬ rection. Heptagon, in geometry, a figure with seven sides or angles. Heraldry is a science intimately con- I nected with the early history of Europe, its chivalry, its conquests, and the bearing of arms : it teaches J how to blazon or explain in proper terms all that belongs to arms; j and how to marshal or dispose with extreme punctualness divers arms on a field. It is in its archae- ; ology and in precedent indisputable. It teaches whatever relates to the marshalling of solemn processions and other public ceremonies, at co- ! ronations, installations of Knights of the Garter, Knights Grand Cross of ; the Bath,Knights Companions, etc.; at the creation of peers, nuptials, christenings of princes, funerals, etc. It is, in fact, an important science, particularly in English history, in tracing the narrative of the families of the nobility and commoners, their holdings, their distinguishing qualifications, in arms, in literature, and in the arts. Hermce, statues of which only the head is carved, and sometimes a portion of the bust: square or cu¬ bical figures of the god Mercury, without legs and arms, anciently placed by the Greeks and Romans at their cross-ways. Herring-bone work, masonry in which the stones are laid aslant instead of being bedded flat. HIN Herse, a portcullis; a frame whereon lighted candles were placed at the obsequies of distinguished persons. : Heterogeneous, opposite or dissimilar , in nature, as opposed to homo¬ geneous. Hewns, in Cornwall, the sides of a calciner or burning-house furnace; so called from their being formerly built with hewn moor-stone. Hexagon, in geometry, a figure of six sides or angles. Hexahedron, in geometry, one of the five regular solids, being the same with a cube. Hexast.yle, a portico of six columns in front. Hexastylos, a frontage of six columns. Hexeres, a vessel with six banks of oars on each side. Hiatus, an aperture, a breach or de¬ fect. Hick's mandril, an arbor for turning rings: at the centre of the arbor there is a cone, round which, at equal distances, wedges are fitted into dove-tailed grooves, and are expanded to the bore of the ring by a nut acting on a screw at the end of the cone. Hickory or white walnut, a native of America. The wood of the young trees is exceedingly tough and flex¬ ible, and makes excellent hand¬ spikes, etc. Hieroglyphic, an emblem, a figure by which a word is implied ; the Egyptian art of writing in picture. High-pressure engine, a non-conden¬ sing steam-engine, worked by the excess of the pressure of the steam upon the piston above the pressure of the atmosphere : in this engine, after the steam has acted upon the piston, it passes through the educ¬ tion-pipe into the air. Hiling, the covering or roof of a building. Hinges, the joints on which doors, gates, etc., turn. Hinges. The diversity of forms into which door furniture has been re¬ solved is almost endless. Many of the ancient hinges were not only 22-1 IIOGARTH. HOL HIP wrought into scrolls and other flo¬ rid devices, but occasionally further enriched with inscriptions. Hip, the external angle formed by the meeting of the sloping sides of roofs which have their wall-plates run¬ ning in different directions. Hip-knob, a pinnacle, finial, or other similar oniament, placed on the top of the hips of a roof or the point of a gable. Hippodrome, a large plot of ground laid out for the exercise of horses ; among the Greeks, a race-course. Hogarth (William) was born in Lon¬ don in 1697. During his struggles to quit silver plate engraving and to fit himself for an artist, Ho¬ garth writes : “ I had learned by practice to copy with tolerable cor¬ rectness in the ordinary way, but it occurred to me that there were many disadvantages attending this method of study, as having faulty originals, and even when the pic¬ tures or prints to be imitated were by the best masters, it was little more than pouring water out of one vessel into another;” again, “ Many reasons led me to wish that I could find the shorter path, fix forms and characters in my mind, and instead of copying the lines, try to read the language, and, if possible, find the grammar of the art, by bringing into one focus the various observa¬ tions I had made, and then trying by my power on the canvas how far my plan enabled me to combine and apply them to practice. For this purpose 1 considered what va¬ rious ways, and to what different purposes, the memory might be applied; and fell upon one most suitable to my situation and idle disposition; laying it down as an axiom, that he who could by any means acquire and retain in his memory perfect ideas of the sub¬ jects he meant to draw', would have as clear a knowledge of the figure as a man who can write freely hath of the twenty-five letters of the al¬ phabet, and their infinite combina¬ tions.”—-Hogarth supported him¬ self "by the sale of his prints—the prices of his paintings kept pace neither with his fame nor with his expectations. -In January, 1745, he offered for sale the six paint¬ ings of the Harlot’s Progress, the eight paintings of the Rake’s Pro¬ gress, the Four Times a Day, and the Strolling Actresses, and received only £427. Is. for his nineteen pic¬ tures. In June, 1750, the six pic¬ tures of Marriage-a-la-Mode were sold by public auction for £110; in 1797 they were sold to Anger- stein for £1381. The four Elec¬ tion Pictures, begun in 1755 and finished in 1758, w’ere sold for £200, and subsequently were sold to Sir John Soane for £1732. Hoggan, in Cornish, a hawthorn- berry, the tinner’s pasty. Hogging, in ship-building, the convex appearance resembling the back of a hog, given to a ship after being first launched, by the dropping of the two extremities. Hogshead, a measure of 63 gallons. Hoist, an apparatus for raising bodies from the ground-floor of a building to a floor above. Holte (Henry), of York, designed in 1612 several buildings. It is con¬ jectured that he designed and com¬ pleted the garden quadrangle build¬ ing at Merton in 1610, and the whole of Wadham College cost £11,360. Hollow newel, an opening in the mid¬ dle of a staircase, the steps only being supported at one end by the surrounding wall, the ends next the hollow unsupported; also a hollow groin, pier, of brick or stone, made behind the lock-gates of canals. Holly is a very clean, fine-grained wood, the whitest and most costly of those used by the Tunbridge- ware manufacturers : it is used for painted screens and a great variety of fancy and tasteful purposes. Holy Trinity {The), in the Table of Symbols of the early ages, by the three-coloured rainbow, encircling l 3 225 HOL HOPS. HOP our Saviour, the visible form of the Deity, who is sometimes seated on it, Ezek. i. 28, Rev. iv. 3; by the beams of light from the hand of Christ; by the extension of the thumb, fore and middle fingers of the Saviour’s hand as held in giving the benediction. Holy-water vessel, the vessel which contains the consecrated or holy water carried in religious proces¬ sions ; also the receptacle for holy water placed at the entrances of Roman Catholic churches. Holy-water stone, the stoup on which the holy-water vessel is placed. Holy - work folk, people who hold lands for repairing or defending a church or tombs, on which account they were freed from feudal and military service. Homestall, or Homestead, a mansion, house, or seat in the country; a farm, with the land adjoining. Homogeneous, a term applied to va¬ rious substances, to denote that they consist of similar parts, or parts of the same nature and kind. Hoodings-ends, the ends of planks which fit into the rabbets of the stem and stern-post of a ship. Hood-mould, a band or string over the head of a door, window, or other opening, in an ancient build¬ ing ; so called from its enclosing, as within a hood, the inferior mould¬ ings and the opening itself. Hood-moulding, a name given to the label-moulding. Hook-pins, taper iron pins, only with a hook head, to pin the frame of a roof or floor together. Hops, Hop-drying. The art of drying hops has been much improved of late years ; emulation amongst landlords and tenant-farmers, in regard to the construction of their oasts, has led to this. Hop-drying is a process of desiccation, of which the object is to drive off the su¬ perfluous moisture from the hops. Hot wind generally dries more quickly than a cold one; that which has the highest temperature will absorb moisture from any sub¬ stance over which it passes more rapidly than the cooler current will. It is not, however, so gene¬ rally apprehended that the converse of the above proposition is also true, and that, with equal tempera¬ tures, that substance over which most air passes in a given time will part with a larger portion of its moisture. The application of the latter principle has been illustrated in low-temperature drying, which has been managed by introducing a considerable quantity of external air into the space beneath the hair, by knocking holes in the external walls. Experiments of this sort have been held to be conclusive as to the superiority of low-tempera¬ ture drying. This, however, is not exactly the case, because as much heat would pass through the hops as before, as long as the fires were kept up as usual; and the true ex¬ planation of the circumstance is that the improved drying is due to the larger quantity of air passed through the hops, rather than to the temperature being reduced. If the fires had been lessened, the temperature might have been low¬ ered as much as was done by the admission of cold air ; but in that case the hops, instead of drying better, would have been found not to dry so well as at the higher temperature. The questions which are for consideration are, the quan¬ tity of air necessary to be admit¬ ted ; the mode of its admission; the method of heating the air ; the proportion and construction of the kiln necessary to give full effect to the above arrangements. The quan¬ tity of air to be admitted is depen¬ dent upon the temperature at which the drying is to be conducted, and upon the weight of moisture to be evaporated. Air at various tem¬ peratures has an ascertained capa¬ city for moisture. When fully sa¬ turated,-— 226 HOP HOPS. HOP Air at 32 deg. contains 1-160 th - ] S 11 59 l-80th 11 86 l-40th 11 113 l-20th 11 140 l-10th 11 167 l-5th 11 194 2-5th 11 221 4-5th The capacity of air for moisture being doubled by each accession of 27 degrees of Fahrenheit. If, then, we desire to know what quantity of air should be admitted to carry off a given weight of moisture at any of the above-named tempera¬ tures, we have only to multiply the weight of moisture by the increased capacity for moisture due toair raised from the temperature of the exter¬ nal atmosphere to that of the kiln. Supposing the weight of water to be evaporated to be 7 cwt., the temperature of the external air 59 degrees, and that of the kiln 113 degrees, 186 cwt. of air would be required to carry off this quantity of moisture. About 13 cubic feet of air weigh a pound, and rather more than 270,000 cubic feet of air must therefore be passed through the kiln during the time of drying. If we suppose this operation to be continued for ten hours, this will give 27,000 feet per hour, or about eight feet per second. To allow of the passage of so large a quan¬ tity of air, the openings for its ad¬ mission must be of a correspond¬ ing area ; and as it is better to ad¬ mit too much air than too little, it would be well to adopt something like the following proportions of openings 6 ft. superficial for a 16 ft. kiln. 8 „ „ 18 „ 10 „ „ 20 „ 12 „ „ 22 „ The method of heating the kiln has been generally regarded as the most important point connected with hop-drying. The requisite conditions are, that the heating surfaces should be largely extended, and that the contact of the air- currents with the heated material should be perfect over the whole surface. Where the former of these conditions does not obtain, a larger quantity of air cannot be heated. In an open fire, the heat¬ ing surfaces are nearly as the area of the fire-bars; in a common cockle they may be estimated as about 2-2| to 1 ; and in the im¬ proved stove, or evaporator, they are as about 30 to 1. The pecu¬ liarities in the construction of the improved stove are:—The situation of the fire in the centre or heart of the stove at a distance from the outer surfaces, which cannot there¬ fore become overheated to the ex¬ tent that takes place where the fuel is in direct contact with the sides. The exceedingly small size of the fire-grate as compared with the area of the fire bars, either of open fires or of ordinary cockles, and the consequent diminution in the consumption of fuel. It has been stated upon competent autho¬ rity that the cost of drying hops by ordinary cockles was about 1 Od. per cwt., as compared with 3s. where open fires and charcoal were used. By the improved stove, the loading of a sixteen-feet kiln might certainly be dried with one cwt. of coals. The more perfect combus¬ tion of the fuel effected by lining the furnace with fire-brick and the higher temperature thereby in¬ duced have much to do with the efficiency of the stove. The com¬ mon cockle being heated entirely by radiated heat, absorbs none of the beat from the smoke, which would escape at a very high tem¬ perature if a further portion of ca¬ loric were not abstracted from it in its circuit of the horizontal flues. The principle of bringing the air as it becomes warmed, in succes¬ sive contact with still more highly- heated portions of the stove, is pur¬ sued throughout. The sides of the stove are surrounded by a brick wall, at a distance of about six 227 HOR HORSE-POWER. HOS inches from the stove at the nar¬ rowest part. This wall confines the air in its ascent, pressing it as it were against the sides, which are made to overhang, in order to give more perfect contact. On reaching the upper part of the side channels the current of warmed air is de¬ flected by inclined cast-iron plates, and made to traverse the pyramidal top of the stove, where it receives its last portion of heat, and then escapes upwards through the tubes with which the deflecting plates are perforated. It is desirable in building kilns to use every precau¬ tion to prevent the loss of heat by radiation to the surrounding atmo¬ sphere. This may be effected by building the external walls hollow, or with hollow bricks. An inner circle answers nearly the same pur¬ pose if there is a door to shut off the communication with the shed, and no openings through the ex¬ ternal walls. The roofs should also be plastered with lime and hair under the tiles before the in¬ ner plastering is done. Attention to this point and to carefully stop¬ ping all air-passages at the foot of the rafters, will prevent the con¬ densation of the reek upon the in¬ terior of the kiln. Hornbeam, a very tough and stringy European wood, used by millwrights for the cogs of wheels; also for plumbers’ dressers, or mallets, etc.) Hornblende, a conspicuous ingredient in the composition of rocks, divided into common hornblende, horn¬ blende-schist, and basaltic horn¬ blende. Horn-stone, a conchoidal and siliceous mineral substance, allied in compo¬ sition to flint, but of a more earthy texture. Horography, the art of constructing dials. Horologium, a name anciently given to any instrument for measuring time. Horse, a large round bar of iron fixed in the head of a ship. Horse, in navigation, the name of a rope reaching from the middle of a yard to its extremity, on which the sailors stand when they are loosing or reefing the sails. Horse-chestnut wood is one of the white woods used by the Tunbridge turners ; it is close and soft, even in the grain, and is much used for brush-backs, etc. Horse-power. Although horses are not all of one strength, yet there is a certain force now generally agreed upon among those who construct steam-engines, which force is de¬ nominated a horse's power, and hence steam-engines are distin¬ guished in size by the number of horses’ power to which they are said to be equal. The measure of a mechanical effect equal to a horse’s pow r er has been much disputed: this, however, can be but a matter of little conse¬ quence, if the measure be generally understood, since there is no such thing as bringing it into any real measure. Some horses will perform double the work of others, and those of one country will work more than those of another. Desaguliers’ measure is, that a horse will walk at the rate of 2J miles per hour, against a resistance of 2001bs.,and this gives, as a number for compa¬ rison, 44,000 ; that is, the raising of 1 lb. 44,000 feet in a minute, or, what amounts to the same, the raising of 44,000 lbs. 1 foot in a a minute. Emerson’s measure is the same as Desaguliers’, and Smeaton’s re¬ sult is 22,916 lbs. under the same circumstances. James Watt found,from repeated experiments, that 33,000 lbs. 1 foot per minute was the average value of a horse’s power: but his engines were calculated to work equal to 44,000 lbs. 1 foot per minute. //. P., the abbreviation forhorse-power. Hortus, a garden or pleasure-ground. Hose-pipes, in locomotive engines, elastic pipes made of canvas, sa¬ turated with a solution of India- 228 HOS HOT-AIR BLAST. HOT rubber, sometimes galvanized, and forming a good elastic connection between the engine and tender feed-pipes. They are now generally used in preference to ball-and- socket connections for conveying the steam to the tender. Hospitalia, anciently the doorways in the scene of a theatre on the right and left of the valvae regiae or prin¬ cipal doorway ; so called because the movable scenes, representing inns or places appropriated for the reception of strangers, were placed near them. Hospitals were originally designed for the relief of poor and impotent per¬ sons, and the entertainment of tra¬ vellers upon the road, particularly of pilgrims, and therefore they were generally built upon the road¬ side ; in later time they have always been founded for fixed inhabitants ; before the spoliation, there existed in England above 358 of these houses of relief. Hostelry, or Hostry, anciently an inn. I Hot-air blast. It was conceived that the presence of sulphur in the air was the cause of blast furnaces working irregularly and making bad iron in the summer months. Subsequently it was stated that one of the Muirkirk iron furnaces, in Scotland, situated at a considerable distance from the engine, did not work so well as the others, which led to the conjecture that the fric¬ tion of the air, in passing along the pipe, prevented an equal volume of the air getting to the distant furnace as to the one which was situated close by the engine : it was considered also, that by heating the air at the distant furnace, its volume would increase in the ratio of the known law, that air and gases ex¬ pand to double their bulk at 448° temperature. Example: If 1000 cubic feet, say at 50° of Fahrenheit, were pressed by the engine in a given time, and heated to 600° of Fah¬ renheit, it would then be increased in volume to 2104 - 4, and so on for every thousand feet that would be blown into the furnace. In prose¬ cuting the experiments which this idea suggested, circumstances, how¬ ever, became apparent which in¬ duced a belief, that heating the air introduced for supporting combus¬ tion into air-furnaces materially in¬ creased its efficiency in this re¬ spect ; and with the view of putting these suspicions to the test, the following experiments were made. To the nozzle of a pair of common smith’s bellows, a cast-iron vessel heated is attached from beneath, in the manner of a retort for gene¬ rating gas, and to this vessel the blow-pipe, by which the forge or furnace was blown, was also at¬ tached. The air from the bellows having thus to pass through the heated vessel above mentioned, was consequently heated to a high tem¬ perature before it entered the forge fire, and the result produced, in increasing the intensity of the heat in the furnace, was far beyond ex¬ pectation, and so evident as to make apparent the fallacy of the generally received opinion, that the coldness of the air of the atmosphere in the winter months was the cause of the best iron being then produced. In overthrowing the old theory, new principles in the process of iron-making were established. Experiments on the large scale, to reduce iron ore in a founder’s cupola, were commenced at the Clyde Iron-works. These experi¬ ments were completely successful, and in consequence the invention was immediately adopted at the Calder Iron-works, where the blast, being made to pass through two retorts placed on each side of one of the large furnaces before entering the furnace, effected an instanta¬ neous change, both in the quantity and quality of iron produced, and a considerable saving of fuel. The whole of the furnaces at the Calder and Clyde Iron-works were HOT HOUSE. HOU fitted ujyon the principle of the hot blast, and its use at these works continues to be attended with the utmost success; it has also been adopted at Wilsontown and Gart- shirrie Iron-works in Scotland, and at several works in England and France. The air as at first raised to 250° of Fahrenheit, produced a saving of three-sevenths in every ton of pig- iron made, and the heating appa¬ ratus having since been enlarged, so as to increase the temperature of the blast to 600° Fahrenheit and upwards, a proportional saving of fuel is effected; and an immense additional saving is also acquired by the use of raw coal instead of coke, which may now be adopted. By thus increasing the heat of the blast, the whole waste incurred in burning the coal into coke is avoided in the process of making iron. By the use of this invention, with three-sevenths of the fuel formerly employed in the cold-air process, the iron-maker is now enabled to make one-third more iron of a superior quality. Were the hot blast generally adopted, the saving to the country in the article of coal would be immense. In Britain, about 700,000 tons of iron are made annually, of which 50,000 tons only are pro¬ duced in Scotland: on these 50,000 tons would be saved, in the pro¬ cess of manufacture, 200,000 tons of coal annually. In England the saving would be in proportion to the strength and quality of the coal, and cannot be computed at less than 1,520,000 tons annually ; and taking the price of coals at the low rate of four shillings per ton, a yearly saving of £296,000 ster¬ ling would be effected. Nor are the advantages of this invention solely confined to iron¬ making : by its use the founder can cast into roods an equal quantity of iron in much less time, and with a saving of nearly half the fuel employed in the cold-air process; and the blacksmith can produce in the same time one-third more work, with much less fuel than he for¬ merly required. In all the processes of metallur¬ gical science it will be found of the utmost importance in reducing the ores to a metallic state. Hospitium, in old writers, an inn or a monastery, built for the reception of strangers and travellers. Hot-house, a glass building used in ji gardening, and including stoves, conservatories, etc. Hot-water pump, the feed-pump of a condensing engine, for supplying the boiler from the hot well. Hot well, the vessel which receives the water from the air-pump. Hour-glass stand, a bracket or frame of iron for receiving the hour-glass. : See ‘ Papers on Architecture,’ vol. iii., which contains a good example. “ By the side of the pulpit still remains the ancient hour-glass and frame.” House, a place of residence. The pur¬ pose of a house being for dwelling, and that of tents being the same, they are called by one name in the Hebrew; on the same principle, the Tabernacle of God, though only a tent, is sometimes called the Tem- N pie, that is, the residence of God. The ordinary buildings or houses in the East have continued the same from the earliest ages, without the least alteration or improvement;— large doors, spacious chambers, ! marble pavements, cloistered courts, with fountains, etc.,—conveniences well adapted to the circumstances of these climates, where the sum¬ mer heats are generally intense. The streets of these cities, the better to shade them from the sun, are usu¬ ally narrow, with sometimes a range of shops on each side. On enter¬ ing one of the principal houses, a porch or gateway will first be seen, with benches on each side, where the master of the family receives visits and despatches business. In 230 HOUSE. HOU houses of better fashion, the cham¬ bers are hung with velvet or damask from the middle of the wall downwards, and covered and adorned with velvet or damask hangings of white, blue, red, green, or other colours. The ceiling is generally of wainscot, either very artistically painted, or else thrown into a variety of panels with gilded mouldings, and with scrolls of the Koran, etc. The stairs are some¬ times placed in the porch, some¬ times at the entrance into the court. When there is one or more stories, they are afterwards continued, through one corner or other of the gallery, to the top of the house, whither they conduct through a door that is generally kept shut, to prevent their domestic animals from daubing the terrace, and thereby spoiling the water which falls from thence into the cisterns below the court, etc. Such in general are the manner and contri¬ vances of the Eastern houses ; and if it may be presumed that our Saviour, at the healing of the para¬ lytic, was preaching in a house of this fashion, it may, by attending only to the structure of it, throw some light on one circumstance of that history, which has given great offence to some unbelievers. The houses of the poorer class of people in the East are of very bad con¬ struction, consisting of mud walls, reeds, and rushes. In Constanti¬ nople everything is sacrificed to outside decorative show: built prin¬ cipally of wood, conflagrations are frequent and extensive. In earlier history, magnificence and refined luxury wei£ combined with the highest and most noble examples of decorative art. The interior of the domestic residences and public edi¬ fices of Herculaneum and Pompeii surpassed every existing example. The houses of the Roman citizens partook also of the refinement of an age of art; and modern Europe has noble examples of domestic HOU dwellings, coeval with the wealth of the country in which they are still to be found. In England, the domestic residence of the noble¬ man, the merchant, and the trader are, besides the elegances of their arrangements, models of comfort and health. Before a house is planned, the proprietor should describe the kind of house he wishes to be built. The architect is to consider what must be had, and what may be dis¬ pensed with. He ought to keep his plan as scrupulously within the expense proposed, as within the limits of the ground he is to build upon; he is, in short, to enter into the views, the wishes, and the ideas of the gentleman who will inhabit the house proposed to be erected. Houses suitable to the different ranks of the community.—Vitru¬ vius instructs us of those parts of private houses which are exclu¬ sively appropriated to individuals of the family, and in what manner these ought to be connected with the apartments into which strangers are admitted ; for there are several parts of a house which may not be approached by those who are not of the household, unless expressly invited; such as the sleeping-rooms, triclinia, baths, and those apart¬ ments which are in general use. The parts which are accessible to all, and into which any person may enter uninvited, are the vestibule, cavaedium, peristyle, and whatever others are built for similar pur¬ poses. Of the proportions of private houses, Vitruvius says :—“ Nothing ought to engage the attention of an architect more than the pro¬ portions of all the parts in the houses he constructs : after having determined upon such proportions as the necessity for the commen- suration of the parts with the entire building seems to require, the great¬ est judgment must be exercised in adapting them to the nature of the 231 HOU HYDRAULICS. HYD spot, the use to which the edifices are designed, and the appearance they ought to assume; and this must be done by making such addi¬ tions or deductions, that, although the proportions are not strictly what they ought to be, the eye may not be conscious wherein they fail. The same objects appear differently under dissimilar circumstances; if near the ground or at a considerable elevation ; if in a confined space or an exposed situation. Under every peculiar circumstance, great judg¬ ment is necessary in calculating the effect which will be ultimately pro¬ duced. The impression made upon the sense of seeing is not always a correct image of the object; for, in painting, columns, mutules, and statues are made to appear pro¬ jecting and detached, when, in fact, every object represented is in one and the same plane. It becomes necessary, in the first place, to in¬ stitute laws of proportion, upon which all our calculations must be founded. According to these, the ground-plan, exhibiting the length and breadth of the whole work and the several parts of it, must be formed. When the magnitude of these is once determined, the parts must be arranged so as to produce that external beauty which suffers no doubt to arise in the minds of those who examine it as to the want of proportion in any part.” The Greeks had a different way of building from the Romans; for, as Vitruvius says, “ instead of mak¬ ing porticoes or galleries and halls, they made the entry to their houses very narrow, placing on one side the stables, and the por¬ ter’s lodge on the other. From this first entry one passed into a court, which had piazzas on three sides, and towards that of the south they made anti, or abut¬ ments of pilasters, which supported the joists of the ceiling more in¬ wards ; because that leaving some space between the one and the other, they had very large places, ; which they appointed for lodging ■ to the mistress of the house, and to the men and women servants. I On the same floor with these abut¬ ments there were some rooms which i may be called antechambers, cham¬ bers and drawing-rooms, being j every one just behind the other.” Souse-bote, an allowance of timber i out of the lord’s wood, to support or j repair a tenant’s house. Housing, a tabernacle, or niche for a statue, was formerly so called. Hovel. The canopies over the heads of the statues of Richard II. and Queen Anne are called hovels or tabernacles. Howl, or To Howie, when the foot- hooks of a ship are scarfed into the ground-timbers, etc. Huel, a work, a mine, as huel stones, a tin mine. Hulk, in Cornwall, an old excavated working ; 1 to hulk the lode.’ Hulk, or hull, the body of a ship. Hummums (Turkish), a sweating house. Hungarian machine, an hydraulic en¬ gine, a very ingenious application of the Rero jet-d’eau principle. Hydraletes, according to Strabo, a mill for grinding corn by water¬ power. Hydraulic belt, an endless double band of woollen cloth, passing over two rollers, the lower part of the belt being immersed in water: it is driven with a velocity of not less than a thousand feet per minute, and the water contained between the two surfaces is carried up and discharged, as it passes over the upper roller, by the pressure of the band. Hydraulic ram, a machine contrived to raise water by means of its own momentum. Hydraulics. The science of hydraulics teaches the method of estimating the swiftness and force of fluids in motion. The science is dignified by the name of hydrodynamics, or the application of dynamics to the HYDRAULIC PRESS. HYD HYD impulsion and flow of water and other liquids, as well as the forces with which they act upon bodies against which they strike, or which move in them. Hydrodynamics , the science of the laws of the motion of fluids, con- sisting of two branches. The science of hydraulics refers princi¬ pally to the machinery for conduct¬ ing fluids ; that of hydrostatics, to the pressure, equilibrium, and cohesion of fluids. Hydrogen. Hydrogen gas is com¬ monly obtained for experimental purposes by the decomposition of water: its name is derived from the Greek words meaning water and to generate. Hydrometer, an instrument for mea¬ suring the specific gravity of va¬ rious spirits and other liquids, by floating in them. Hydroscope, an instrument intended to mark the presence of water in air. Hydrostatic or Hydraulic Press, a machine adapted for giving great pressure in cases where little mo- tion is required. The contrivance of this apparatus is due to the ce¬ lebrated mechanician, Joseph Bra¬ mah, w r ho obtained a patent for it on the 31st of March, 1796, under the title of ‘ certain new methods of producing and applying a more considerable degree of power to all kinds of mechanical apparatus and other machinery requiring motion and force, than by any means at present practised for that purpose.’ The action of this press is founded upon the fundamental principle in hydrostatics, that “ when a liquid mass is in equilibrium, under the action of forces of any kind, every molecule or part of the mass sus¬ tains an equal pressure in all direc¬ tions.” From this it follows, that a pressure exerted on any portion of the surface of a confined mass of fluid is propagated throughout the mass, and transferred undiminished to the entire surface in contact with the water. The first sugges¬ tion of the hydraulic press is con¬ sidered to have been made by Pas¬ cal in the middle of the 17th cen¬ tury ; but Bramah was the first to carry this suggestion into practice, by devising and applying apparatus in various forms for the purpose of producing pressure. Since the data of its invention, the hydraulic press has been ex¬ tensively used in pressing goods of various kinds. Another of its most useful applications is to the testing Fig. 1. of girders and beams of cast-ii-on, (See article Bramah’s Hydrostatic Press.) Its latest and perhaps most remarkable duty is that of lifting the iron-work of tubular bridges en masse from the water-level to their final altitude. Hydrostatic presses consist es- 233 HYDRAULIC PRESS. HYD sentially of two distinct parts, viz. the press, or machine in which the force acquired is applied, and the pumping apparatus, by which the water is forced into the press; these two parts of the entire machine being connected only by the pipe Fig. 2. through which the water passes from one to the other. Of the ac¬ companying figures, Nos. 1 and 2 show the main parts of the press, viz. the cylinder, into which the water is admitted; the ram, or solid plunger or piston ; and the cross¬ head by which the pressure at the end of the ram is distributed over a lengthened surface for use. The figures show the cylinder as sup- HYD ported in a frame upon girders, in a manner similar to that adopted in raising the tubes of the railway bridge erected at Conway. Fig. 3 shows the section of a portableforcing-pump as commonly used for proving castings with the hydraulic press, for which purpose the press is applied horizontally, and mounted on an iron carriage for portability. But, however va¬ ried in arrangement for particular purposes, the pump and the press consist of the same essential parts, as follows : the pump comprises a cistern or kind of pail for contain¬ ing the water, and into which a barrel descends nearly to the bot¬ tom. The barrel is fitted with a plunger, by working which, the water is driven through a small tube or pipe into the press. The pump is furnished with a safety- valve, and also with a screw for letting off the water as required. The press consists of a strong hol¬ low cylinder of cast-iron, close at one end, and of a solid ram work¬ ing through the other end, the water-pipe being inserted through the metal of the cylinder in a water¬ tight screwed aperture. Fig. 1 is an elevation of the press; fig. 2, a vertical section of the press, taken at right angles to the elevation; and fig. 3, a vertical section of a pump: a is the cast-iron cylinder; b, the ram ; c, the casing or frame of the cylinder; d d are two cast- iron girders supporting the casing; e is the cast-iron cross-head; //, two guide-rods; g, the water-pipe from the pump, with a lever-valve at h, by closing which the pressure will be retained, should the pipe burst. On fig. 3,^’ shows the other end of the water-pipe, which is at i screwed into a stuffing-box on the pump; k is the lever of the safety- valve, a, which is cylindrical, and finished with a conical end, which fits a seating of similar form ; l is a standard bolted at m to the cover of the cistern, and having an eve- 234 HYD HYDRAULIC PRESS. HYD boss at n, for guiding the plunger; o p is a link pinned to the plunger; q is the pail or cistern for holding the water; r, the barrel passing through an opening in the cover, and fixed to it with bolts and nuts ; s, the lower valve-seat, and conical Fie. 3. three-sided valve, the former being screwed into the end of the barrel; t, a tube depending from the valve- seat s, and screwed upon it: this tube reaches nearly to the bottom of the cistern, and is perforated at the end with minute apertures, through which the water is ad¬ mitted without dirt or particles, which would injure the working of the pump ; u is the plunger, which works through a stuffing-box on the top of the barrel, and is made with a slot at v, to receive the link o p, which is pinned to it and also to the pump-handle; w is the plunger-rod, screwed into the upper end of the plunger; y, the pump- handle, jointed to the standard at x. During the first part of the action of the pump, while no great pres¬ sure is yet produced, the handle is pinned to the outer of these holes, as it makes a larger stroke with the piston, and thus saves time: the pin is afterwards removed to the inner hole, to have all the ad¬ vantage of the leverage, z is the upper or discharge valve, with a conical end : it is introduced from the top, and covered with a short screw, which likewise re¬ gulates the lift of the valve. This valve is form¬ ed by being simply filed flat out of the round. The rule for finding the increase of power commanded by the pump is derived,—first, from the ratio of the areas of cross-section of plunger of pump and ram of press; and, secondly, from the ratio of the le¬ verage of the pump-handle. Thus suppose the plunger to be % inch and the ram 6 inches in diameter, and the arms of the lever or handle as 1 to 4, the power will be thus found :— •5 2 : 6 2 multiplied by 1 : 4 J •25 : 144, that is, 1 : 576. And thus a power equal to 201bs., applied on the end of the pump- handle, will produce a pressure equal to ll,5201bs. on the ram, or 5 tons 2 cwt. 3 qrs. 121bs. Each of the presses applied at Conway was worked by a steam- engine having a horizontal cylinder 17 inches in diameter and 16 inches stroke, with piston-rods working through stuffing-boxes at both ends 235 HYD HYGROMETER. IDE of the cylinder. The piston-rods worked two forcing-pumps, with plungers l T l jr inch diameter and 16 inches stroke. The rams of these presses were each 5 feet 2 inches long and 18f inches in diameter, with a space nearly £ inch wide around. The cylinders were 37i inches diameter externally, and 20 inches internally, the metal being inches in thickness: the orifice of the water-tubes f inch in dia¬ meter. Hydrostatic paradox. This may be explained upon the same principles as the mechanical powers ; and an explanation conducted in this man¬ ner strips it of its paradoxical ap¬ pearance. Hydrostatics, the science which treats of the mechanical properties of fluids; strictly speaking, the weight and equilibrium of fluids. The weight and equilibrium of fluids at rest are the objects of this science. When the equilibrium is destroyed, motion ensues; and the science which considers the laws of fluids in motion is hydraulics. Hygrometer: this instrument is used to ascertain the quantity of mois¬ ture held in the atmosphere. There are several kinds of hygrometers in use,namely, De Luc’s, Saussure’s, Leslie’s, and Professor DanielPs. The latter is considered preferable. Hypoethral, open above: in temples of this description the cella was in part exposed to the air: they had a double range of columns within the cella, dividing it into three alae, or aisles. The alae on either side were roofed, but that in the middle had no covering. Hypcethrum, a latticed window over the entrance-door of a temple. Hyperbola, a section of a cone made by a plane, so that the axis of the section inclines to the opposing leg of the cone, which in the parabola is parallel to it, and in the ellipse intersects it. Hyperthyrum, that part of the frame of a doorway which is over the supercilium. In Greek architec¬ ture, a frieze and cornice supported by friezes and consoles. Hypocastanum, or chestnut brown, is a brown lake prepared from the horse-chestnut: it is transparent and rich in colour, warmer than brown pink, and very durable both in water and oil; in the latter it dries moderately well. Hypocausis, among the Greeks, a fur¬ nace with flues running underneath the pavement of an apartment, to increase the temperature. Hypocaustum, the stove-room of a bath, in which was placed the prse- furnium for heating the caldaria. Hypoyceum, in ancient architecture, a name common to all the under¬ ground parts of a building. Hypotrachelium, that part of the ca¬ pital of a column which occurs be¬ tween the shaft and the annulets of the echinus. I. Ice-house, a subterranean chamber for preserving ice from the ordinary changes of temperature. Ich Dien, in heraldry, 1 1 serve.’ Ichnography, in drawing. The ichno- graphy of a building represents the plan or groundwork; the ortho¬ graphy, the front; and the sceno- graphy, the whole building. Icosahedron, in geometry, a regular body or solid, consisting of twenty triangular pyramids. Ideas. 1. Formation of ideas, inteL lect, mind, understanding, reason, thinking principle, nous, sense, common sense, consciousness, ca¬ pacity, intelligence, intellection. 2. Precursory conditions and ope¬ ration. 3. Materials for reasoning. 4. Reasoning processes. 5. Results of reasoning. 6. Extension of thought. 7. Creative thought. Communication of Ideas. 1. Nature of ideas communicated, 236 INDIAN ARCHITECTURE. IMA meaning, signification, sense, modes of communication, means of com¬ municating ideas. Individual Volition. 1. Will, volition, free-will. 2. Prospective volition. 3. Voluntary action. 4. Antagonism. 5. Results of voluntary action, intersocial voli¬ tion. Image, a term applied to a statue. Imbowment , an arch or vault. Immure, a wall or inclosure. “ With¬ in whose strong immures.”— Shak- speare. Impages, the horizontal parts of the frame-work of doors, commonly termed rails. Impetus, in mechanics, violent ten¬ dency to any point, violent effort, force, momentum, motion. Impinge, in mechanics, to fall against, to strike against, to clash with. Impluvium, the cistern in the central part of the court or atrium of a Roman house, to receive the rain¬ water. Impost, the horizontal mouldings or capitals on the top of a pilaster, pillar, or pier, from which an arch springs: in classical architecture the form varies in the several orders. Sometimes the entablature of the order serves for the impost of an arch. Impost, archivolt, and keg-stone. The height of the impost should be from one-ninth to one-seventh of the width of the aperture, and the breadth of the archivolt not more than an eighth nor less than a tenth of it. The breadth of the under-side of the key-stone should be the same as the breadth of the archivolt, and its sides, of course, concentric; its length, once and a half its breadth, hut not more than double its breadth. Impulsive force is that which acts I during an extremely short time, and is so called because the forces that take place in any impulse, or impact, are speedily exhausted. | i Incise, to cut, to engrave, to carve. ■ Inclined plane (the), in mechanics, is 237 IND a plane which makes with the hori¬ zontal plane any angle whatever, forming one of the simplest me¬ chanical powers. The inclination of the plane is measured by the angle formed by two lines drawn from the sloping and the hori¬ zontal plane, perpendicular to their common intersection. Increment, an increase, produce. Incrustation. If water, impregnated with calcareous matter, remains long in contact with extraneous substances, an earthy incrustation takes place that soon encloses the incrusted substance, which is then said to be petrified. Incrusted, in architecture, applied to walls or columns covered with precious marble or stone. Incumba, that part of a column or pillar on which the weight of a whole building lies. Indian Architecture consists of two distinct styles,—the Buddhist and the Brabminical,-— theformer being the earliest, and consisting of topes or tumuli, large domical buildings of brick or stone, either quite solid or containing one or more small chambers, in which are deposited relics, coins, and other similar ob¬ jects, which the greater number of them were erected to enshrine. The principal topes are now found in Ceylon and Affghanistan, but they also exist in Burmah and in other neighbouring countries. The next class of Buddhist buildings are the Chaitya halls, similar in plan and use to the early basilicse: these exist principally in caves in India. And lastly, viharas or monasteries, in which the monks attached to the Chaitya halls re¬ sided : these also exist principally as caves in India, and as structural buildings in all countries where Buddhism is still practised. Brahminical or Hindoo architec¬ ture consists mostly of temples, pro¬ perly so called. These in almost every instance are towers, square in plan, or nearly so, built over the cell IND INDICATOR. INE or sanctum of the temple. In the south of India, the upper part forms a right-lined pyramid; in the north, the outline is curvilinear,sometimes tapering to a spire. To these towers are attached porches of greater or less dimen¬ sions. In the north there are generally square halls without pil¬ lars—in the south, as universally pillared — sometimes attached, at others detached from the temple itself: in the latter case, in the south, some of the porches possess from 500 to 1000 pillars, though this is never the case in the north. These temples are generally sur¬ rounded by a square court: in the south, three, four, and sometimes even seven such enclosures sur¬ round the principal cell, the outer one being, in many instances, some miles in circumference. These Hindoo temples exist sometimes, though rarely, as rock- cut temples ; but generally they are structural. Between these styles comes a third, the Jaina style, being a mix¬ ture of the two, possessing some of the characteristics of both, and frequently displaying more ele¬ gance than the first, and less taw¬ driness than the other. By the introduction of domes, whose use was thus brought to great perfec¬ tion, an element was added which was a great improvement on the other two styles, and from which that of Jaina originated. The absence of the arch in all constructions of every age is gene¬ ral throughout India, as the prin¬ ciple was quite unknown. The upper parts of the buildings were supported on square piers or pil¬ lars, and from all sides of their capitals brackets projected equal to their width, and leaving gene¬ rally a space equal to three diame¬ ters between their greatest projec¬ tion, thus leaving only one-half of the whole length of the architrave unsupported ; but when a greater space was required, a succession of projecting brackets, placed above each other, was adopted, sometimes meeting in the centre, and thus having the effect of the horizontal arch. Indian Ink : the pigment well known under this name is principally brought from China in oblong cakes, of a musky scent, prepared for painting in water, etc. Indian red, a colour, is brought from Bengal, and is a very rich iron ore, or peroxide of iron. It is an ano¬ malous red, of a purple-russet hue, of a good body, and valued, when fine, for the pureness and lakey tone of its tints. Indian yellow is a pigment long em¬ ployed in India and subsequently introduced generally into painting in European countries. It is im¬ ported in the form of balls, is of a fetid odour, and is produced from the urine of the camel. It has also been ascribed, in like manner, to the buffalo, or Indian cow, after feeding on mangoes; but the latter statement is incorrect. Indian yel¬ low resists the sun’s rays with sin¬ gular power in water-painting. Indicator, the apparatus for showing the force of the steam, and the state of exhaustion in the cylinder during the stroke. Inigo (Jones), born in London, was first employed at Oxford in 1635 ; he built the arcades and porticoes of the inner quadrangle of St. John’s College with a gallery over; also York-stairs, Strand; and his magnificent design for a royal palace at Whitehall has not yet been surpassed. Indigo, or Indian blue, is a pigment manufactured in the East and West Indies from several plants, but principally from the anil or indi- gofera. Inertia, the passiveness of matter: matter has not the power of putting itself into motion, neither has it the power of stopping itself when put into motion by the action of INTERCOLUMNIATION. INF an external force, as it requires as much force to stop a body as it requires to put it in motion. Inflammable air, hydrogen gas. Influx, in hydraulics, the act of flow¬ ing into any thing, as the tide into a bay or river. Injection-cock, the stop-cock in the ejection-pipe, for shutting off the supply of cold water used for the condensation of steam. Injection-pipe, the pipe through which the injection water passes to the condenser ; in a steam-vessel the injection-pipe is open to the sea, at the bottom of the vessel. Inn, or hostel, anciently a lodging- house, or a house of lodging and refreshment for travellers : houses for lodging the collegians at Cam¬ bridge and Oxford were so called. Inns of court, houses in which there are many lodgings for the accom¬ modation of students and practi¬ tioners at law. Innate force, in physics, the vis iner- tiae. Inner-post, in ship-building, a piece brought in at the fore-side of the main-post, and generally continued as high as the wing-transom, to seat the other transoms upon. Insertum opus, according to Vitru¬ vius, a mode of building walls used by the Romans, in which the stones were small and unhewn, similar to what is now called rubble-work. Insulated columns, in architecture, are those which are unconnected with any wall or building. Intaglio, in sculpture, etc., anything that has figures engraved on it, so as to rise above the ground. Intense blue, indigo refined by so¬ lution and precipitation, in which state it is equal in colour to Ant¬ werp blue. By this process, indigo also becomes durable, and much more powerful, transparent, and deep. It washes and works well in water; and in other respects it has the common properties of indigo. Intercolumniation. The space be¬ tween two columns is called an in- -- 239 INT tercolumniation. When columns are attached to the wall, this space is not under such rigorous laws as when they are quite insulated ; for, in the latter case, real as well as apparent solidity requires them to be near each other, that they may better sustain the entablatures which it is their office to carry. Different sorts. —The dif¬ ferent intercolumniations had the following names bestowed on them by the Greeks, and they still retain their ancient appellations :— Pycnostylos, when the columns are once and a half of their diameter dis¬ tant from each other. Systylos .. when their distance from each other is two diameters. Eustylos .. when their distance from each other is two diameters and a quarter. Diastylos .. when their distance from each other is three diameters and quarter. Aneostylos. when their distance from each other is four diameters. In the Doric, however, the in- tercolumniation is regulated by the disposition of the triglyphs in the frieze ; for the triglyph ought al¬ ways to be placed over the centre of a column, and the metope should be square. In the Tuscan inter¬ val, the architraves being of wood, the space may be considerably ex¬ tended. A strict adherence to the above- named intervals between the co¬ lumns produces some irregularity in the arrangement of the modil- lions and dentils of the Corinthian, Ionic, and Composite cornices, which, though not offensive, is better avoided. Vignola therefore has, with some propriety, made his eustylos intercolumniation equal to two diameters and one-third in all but the Doric order. INT IODINE SCARLET. IOD Inter calumniations. Columns may be said to be either engaged or insu¬ lated : when insulated, they are either placed very near the walls or at some considerable distance from them. With regard to engaged columns, or such as are near the walls of a building, the intercolumniations are not limited, but depend on the width of the arches, windows, niches, or other objects, and their decorations, placed within them. But columns that are entirely de¬ tached, and perform alone the office of supporting the entablature, as in peristyles, porches, and galleries, must be near each other, both for the sake of real and apparent so¬ lidity. The ancients had several man¬ ners of spacing their columns, which are described by Vitruvius in his third and fourth books. Those practised in the Ionic and Corinthian orders were, the pyc- nostvle, the systyle, the eustyle, the diastyle, and the araeostyle. In the Doric order they used other intercolumniations, regu¬ lating them by the triglyphs, of which one was always to be placed directly over the middle of each column, so that they were either systyle monotriglyph, of one dia¬ meter and a half; diastyle, or araeostyle: the Tuscan intervals were exceedingly wide, some of them being above seven diameters, which, as the architraves were of wood, was practicable. Vitruvius intended the five inter¬ columniations, mentioned in his 3rd book, merely for the Ionic and Co¬ rinthian orders; the latter of which, according to him, differed from the former only in its capital; for, in the second and seventh chapters of his fourth book, he establishes other intervals for the Doric and Tuscan orders. Nevertheless, they have employed these intercolumniations in different orders. Palladio has used the systyle in the Corinthian and the araeostyle in the Tuscan ; by which means the Corinthian peristyle, of which the character should be extreme delicacy and lightness, becomes twice as strong and material as the Tuscan, of which the distinguishing characte¬ ristics ought to be extreme solidity. Interdentals. The space between two dentals. Interlignium, in ancient architecture, the space between the ends of the tie-beams. Interpensivee, timbers in the roof of the cavaedium, extending in a dia¬ gonal direction from the angles made by the walls of the court to the angles made by the junction of the beams supporting the roof. Intrados, the soffit or under-surface of an arch, as opposed to extrados. In vacuo, a void or empty space. Invention, in painting, consists prin¬ cipally in three things: first, the choice of a subject properly within the scope of art; secondly, the sei¬ zure of the most striking and ener¬ getic moment of time, for represen¬ tation ; and lastly, the discovery and solution of such objects, and such probable incidental circum¬ stances, as, combined together,may best tend to develope the story, or augment the interest of the piece. The cartoons of Raphael furnish an example of genius and sagacity in this part of the art. Inverse, turned back or inverted ; op¬ posed to direct. Inverse ratio, when more requires less, or less requires more. Inverted arch, an arch of stone or brick, with the crown downwards, commonly used in the construction of tunnels. Iodine scarlet is a new pigment, of a peculiarly vivid and beautiful co¬ lour, exceeding even the brilliancy of vermilion. It has received se¬ veral false appellations, but is truly an iodide or biniodide of mercury, I varying in degrees of intense red¬ ness. It has the body and opacity of vermilion, but should be used 240 IOD IRON. 1RO with an ivory palette-knife, as iron and most metals change it to co¬ lours varying from yellow to black. Iodine yellow, ioduret of lead, is a precipitate from an acid solution of lead by an alkaline solution of iodine, of a bright yellow colour, which, from its active chemical affi¬ nities, and the little experience of its qualities in painting, is to be employed with doubt and caution. Ionic capital. The Greek architects must have possessed much science in the formation of curves of every description. We cannot generate the curve of the volute of an Ionic capital hut by approximation ; but the inventors of the order must have known how to generate this and other curves in Greek architec¬ ture, on fixed principles ; so must the artist in'vases, etc. Mr. Jop- ling is said to have discovered the true generic curve. : Ionic Order: this, says Palladio," had its origin in Ionia, a province of Asia; and we read that the famous temple of Diana at Ephesus was built of that order. The column, with its capital and base, is nine modules high; and by a module is understood the diameter of a column below. The architrave, frieze, and cornice, have the fifth part of the height of the column. When the columns are single, the inter-columns are of two diameters and a fourth part, and this is the most beautiful and commodious manner of all inter columns, which Vitruvius calls eustylos.” Amongst the ancients, the form of the Ionic profile appears to have been more positively deter¬ mined than that of any other order; for in all the antiques at Rome, the temple of Concord excepted, it is exactly the same, and conformable to the description which Vitruvius has given of it. Modern artists have likewise been more unanimous in their opinions upon the subject; all of them, ex¬ cepting Palladio and his imitators, having employed the dentil cornice, and the other parts of the profile, nearly as they are found in the Co¬ liseum, the temple of Fortune, and the theatre of Marcellus. In Palladio’s works we meet with three different Ionic entablatures, all of them very beautiful. The first is the true antique, which he has made use of at the palace of the Porti; and in several doors and windows of the Thiene and Val- marana palaces, in Vicenza. The second is a very judicious imitation of the entablature in the temple of Concord, and is executed by him in the upper arcade of the basilica in the same city. The third, which is an invention of his own, being the same with that in his book, he has employed with some small dif¬ ference at the Chiericato palace, at the rotunda of Marchese Capra, and in various others of his build¬ ings in the Vicentine, or at Venice. Iron, the most useful and the most abundant of the metals, is found in various conditions of ore in most parts of the earth. Those ores which are principally worked for the production of the metal for manufacturing purposes, are either oxides or carbonates, that is, they contain the metal in a state of combination either with oxygen, or with oxygen and carbonic acid. The oxides are the best ores, and are found in vast beds in Sweden : the carbonates are inferior in point of strength and ductility, and there¬ fore require an extensive reduction. They form the greater portion of the iron ores of Britain. The principal varieties of the ox¬ ides of iron are,—the magnetic; the massive, found in the north of Europe, and other parts of the world; the micaceous, found in the lava of volcanoes, etc.; and the red and brown haematites, found in Great Britain and Europe. The principal varieties of the carbo¬ nates are,—the massive, found in Great Britain and Ireland, Europe, 1 241 ! IRO IRON. IRO and America; and also the argil¬ laceous, commonly known as clay iron-stone, found abundantly in beds and coal deposits in England, Wales, and Scotland. Besidestheoxides and carbonates here enumerated, iron is found in large quantities in combination with sulphur; and the severalcompounds thus formed are known as pyrites, several varieties of which are found in Norway, Sweden,Germany,Ame¬ rica, and in many parts of England. Various artificial oxides of this metal are applied to medicine, dye¬ ing, and other purposes in the arts. The tenacity and strength of iron are impaired by its adultera¬ tion wdth foreign matters. Thus, of the oxides and carbonates, those are best in which the proportion of the metal is great. . These qua¬ lities are further increased by fu¬ sion, and by the mechanical pro¬ cess of hammering; and this fact points to the main distinction in the kinds of iron as applied for manufacturing purposes, viz. foun¬ dry iron and forge iron. In the manufacture of iron, the first process is the reduction of the iron-stone or ore, technically called the mine, into the state of a metal. This is done by fusion in a furnace, with coke added to produce com¬ bustion, and limestone to act as a flux and assist the fusion of the ore. An artificial current of air is neces¬ sary to fuse the ore in these furnaces, which are therefore called blast fur¬ naces, and provided with tubes or tuyeres, through the tapered noz¬ zles of which strong currents of air are delivered to the interior of the furnace, the required velocity of the blasts being sustained by steam or other power. Formerly the air was thus introduced at the same tempe¬ rature as that of the external atmo¬ sphere ; but a plan has for many years been extensively adopted of previously heating the air for the blasts in separate vessels to a high temperature, by which the fusion of the ore is so powerfully assisted, that the saving of fuel in the furnace is many times greater than the quantity used for the preparatory heating of the air. Furnaces thus supplied are termed hot-blast fur¬ naces, and the product is called hot- blast iron, while that made with un¬ heated air is called cold-blast iron. The cost of the process of reduc¬ tion with the hot blast being so much less than of that with the cold blast, the ultimate value of the former is of course also partly de¬ pendent upon the quality of the produce. On this head much differ¬ ence of opinionhas often been mani¬ fested, and with all the earnestness usually displayed in the advocacy of self-interest. The value of each process must, no doubt, arise from the completeness of the fusion pro¬ duced, and the separation effected between the iron and the impuri¬ ties combined with it in the ore. The hot-blast furnace effects the fusion more readily than the cold- blast, but admits a larger combina¬ tion of cinders with the ore; and the advantage which has been taken of this facility of adulteration, in order to reduce the cost of pro¬ duction, has doubtless led to the introduction into the market of many qualities of hot-blast iron which are inferior in strength to that made with the cold blast. The results of some of the most care¬ fully conducted experiments which have been made upon the strength of cast-iron, and published in the 6th volume of the new series of ‘ Memoirs of the Literary and Phi¬ losophical Society of Manchester,’ show that the transverse strength of the cold-blast iron tried was about 2| per cent, greater than that of the hot-blast. The experi¬ ments here referred to were made upon rectangular bars 1 inch square, and 4 feet 6 inches long between the supports. The mean average breaking weights, placed at the middle of these bars, were— 242 In 21 samples of hot- blast iron .... 445-5714 In 22 samples of cold- blast iron .... 456-9090 The metal is allowed to flow from the furnace into rude channels formedonthe surface of the ground, where it cools, and is taken up in the form of rough bars about 3 feet long, and each weighing nearly one cwt., which are technically called pigs. In the making of one ton of pig-iron in Staffordshire, the fol¬ lowing materials are used:— Coal, 2 tons 5 cwt. If coke is used instead of coal, 1 ton 17 cwt. Charred mine, or ore, 2 tons 5 cwt. to 2 tons 10 cwt. Limestone, 13 cwt. to 16 cwt. In the condition of pig-iron, the metal forms the. two staple de¬ scriptions of foundry iron and of forge iron, according to its quali¬ ties, and the proportion of carbon and oxygen winch it contains. The several sorts of pig-iron are consi¬ dered to be six in number, and are thus distinguished: Nos. 1, 2, and 3, foundry iron, of which the first 1 two are never used for forge iron. No. 3, or dark grey, and also the fourth quality known as bright iron, are sometimes used for the foundry, and sometimes for the forge. The fifth and sixth sorts, known as mottled iron and white iron, are never used for the foundry. The order here observed corresponds with that of the proportion of car¬ bon and oxygen mixed w'ith each kind of the iron, and also with that of the fluidity to which the metal is reducible : it also corresponds with the scale of their softness and toughness. Thus, No. 1 has the most carbon and oxygen, and the white iron has the least. No. 1 is the most fluid when melted, and the white iron the least so. Again, No. 1 is the softest, and the white iron the hardest; and No. 1 is the tough¬ est, while the white iron is the most brittle. But white iron is the best adapted for conversion into malleable iron, while Nos. 1 and 2, foundry iron, contain so large a pro¬ portion of carbon and oxygen, that they are totally unfit to be manu¬ factured into bars. The conversion of pig-iron into malleable iron is effected by ex¬ tended processes, or subsequent to those by which the ore has been reduced to the form of pig. These processes are as follow :— 1. Refining.—2. Puddling, ham¬ mering, and rolling,—3. Cutting up, piling, and rolling; the 3rd series of operations being re¬ peated. The refining is for the purpose of separating a portion of the car¬ bon from the pig, and is performed in furnaces fitted with tuyeres for supplying a blast of air to the point of fusion. The metal run from the refining moulds is exceed¬ ingly brittle, and is then broken up into small pieces, and committed to the puddling or reverberatory furnace, to undergo a further puri¬ fication from the oxygen and car¬ bon w-hich remain after the process of refining is accomplished. While in this furnace, the mass into which the pieces of refined metal become clustered is worked and stirred about by the workman or puddler, until its thickness and tenacity are so far increased that it may be formed into lumps, or balls, which the puddler does with tools adapt¬ ed to the purpose. The hammering or shingling is performed upon the balls or blooms of puddled iron, with a very heavy hammer, worked by a cam-wheel, and has the effect of improving the solidity of the metal, and reducing the balls into an oblong form, by which they are better prepared for the action of the rollers. The rolls or rollers are fitted to¬ gether in pairs, and so formed in the periphery and arranged in size, that open spaces are formed be- 243 m 2 IRO IRON. IRO tween them, through which the metal is passed while hot; and each succeeding pair of rollers present¬ ing a smaller space, the iron which is drawn through them becomes proportionately reduced in size and increased in length. The metal has thus been convert¬ ed from a hard, brittle, and readily fusible substance into a malleable bar, which is soft, tough, and very difficult of fusion; but it is still far from fit for the smith’s use, being to a great extent unsound in struc¬ ture, imperfect in tenacity, and irregular on the surface. The third set of processes is now commenced by cutting up the puddled bars into lengths with powerful shears. These lengths, of various dimensions, according to the sized bars to be produced, are carefully piled up and heated in another furnace similar to the pud¬ dling furnace, and which is called the balling furnace. In this the bars are simply heated to a degree which admits of their becoming welded together in the pile and adapted for reduction to the form of finished bars in the rolls. The rolling is the last operation in the making of bar-iron. The metal is dr ■'.asm successively through a series of rollers, that is, between the peripheries of each pair of rollers, and thus gradually reduced in size, increased in length, and freed from the cinder and other impurities which remain after the puddle - rolling has been per¬ formed. The last set of operations is some¬ times repeated in producing iron for superior purposes. The pro¬ cesses here described will give a general idea of the manufacture of iron from the native ore into the form of malleable bars ; and it may be readily conceived how an exten¬ sion and variation of the process of rolling may be made to produce the Several other forms in which this tnetal is prepared for the construc¬ tions of the engineer, the smith, and the machinist. As varieties of bar-iron may be mentioned,—L, or angle-iron ; T, or tee-iron ; and H, or deck-beam iron ; which are prepared in several sizes for the construction of roofs, iron vessels, etc. The malleable rails used for railways are also produced by an arrangement of rollers. Boiler-plate iron, sheet-iron, lioop-iron, and nail rod-iron, are produced from the form of bars by the processes of heating and rolling, or hammering, as required. Boiler¬ plates require, according to the desired strength and size, several repetitions of heating, hammering, and rolling. Sheet-iron is distin¬ guished from boiler-plate by being thinner; hoop-iron is rolled in the same manner as the bars, but be¬ tween rollers without grooves in their edges, the requisite thickness being effected by successive pas¬ sages through the rollers, which are brought nearer to each other at each process, by means of adjust¬ ing screws. Nail rod-iron is rolled in thin bars, which are, while still hot, passed between steel cutters that slit them up into the form of small rods, which, although rough, are well fitted to be manufactured into nails. A very useful form of sheet-iron, which should be noticed, is that of corrugated iron, which is produced by passing the sheets between rollers having grooved peripheries. By this form, the strength or stiff¬ ness of the sheet is so much in¬ creased,that sheet-iron thus formed may be usefully applied to a great variety of purposes for which it is otherwise, owing to its thinness and pliability, utterly inadequate. By the combustion of charcoal with the coke, and the adaptation of a peculiar furnace in the process of smelting, Mr. Clay has succeeded in producing malleable iron direct from the ore, and thus materially ----- 1 - 244 IRO ITALIAN ARCHITECTURE. ITA reducing the series of processes here described. The results thus brought out are of a very interest¬ ing character, and promise to ac¬ quire a great practical value. Mr. Bessemer has patented most suc¬ cessfully some inventions for making iron and steel without the aid of puddling. See ‘ Engineer’s Pocket Book ’ for description. Iron. Moses forbade the Hebrews the use of any stones to form the altar of the Lord, which had been in any manner wrought with iron ; as if iron communicated pollution. He says, the stones of Palestine are of iron, that is, of hardness equal to iron, or, being smelted, they yielded iron. “ An iron yoke ” is a hard and insupportable dominion. “ Iron sharpeneth iron,” says the Wise Man, “ so a man sharpeneth the countenance of his friend: ’ ’ the pre¬ sence of a friend gives us more confidence and assurance. God threatens his ungrateful and per¬ fidious people with making the heavens iron , and the earth brass ; that is, to make the earth barren, and the air to produce no rain. Chariots of iron are chariots armed with iron, with spikes and scythes. Iron ship building, a new and a most successful mode of construc¬ tion of ships in the hull of iron, both for merchant and war pur¬ poses, and for passenger vessels, upon any scale of dimensions. See vol. 54, John Grantham on Iron Ship Building, in the ‘Rudimen¬ tary also separately, with ‘ Atlas of Practical Examples’ in large en¬ gravings. Iron-stone, iron-bound stone, in colour of a bluish grey: it contains but little iron, and is hard to work. Iron-stone has the appearance of rusty-black shale, and, when laid together in large heaps, is so com¬ bustible that it ignites, leaving a calx of 60 per cent, of iron. It abounds in Scotland. Common iron-stone is also very abundant in connection with coal, and in former times formed the principal supply, which induced the foundation of the Carron Iron-works. Iron-wood is imported from the Bra¬ zils, the East and West Indies, and other countries, in square and round logs, 6 to 9 inches and up¬ wards through. Its colours are very dark browns and reds : some¬ times it is streaked, and generally straight-grained; used principally for ramrods, turnery, etc., and is extremely hard. Iron yellow, jaune de fer, or jaune de Mars, etc., is a bright iron ochre, prepared artificially, of the nature of sienna earth. The colours of iron exist in endless variety in na¬ ture, and are capable of the same variation by art, from sienna yel¬ low, through orange and red, to purple, brown, and black, among which are useful and valuable dis¬ tinctions, which are brighter and purer than native ochres. Irrigation, watering the ground. Isochronism, in mechanics, the per¬ forming of several things in equal times ; such as the vibrations of the pendulum. Isodomon, a building every way straight. Isodomos, in Greek architecture, ma¬ sonry cut and squared to the same height, so that, when laid, the courses were all regular and equal. Isometrical, projections and drawings so termed. Isoperimetrical, in geometry, such figures as have equal perimeters or circumferences. Isosceles, in geometry, a triangle that has only two sides equal. Isothermal, in chemistry, equal heat. Italian Architecture, a style now much appreciated, not only in Italy, but in England and France, was first in¬ troduced at the revival of classical architecture, and was subsequently much improved, and adapted to modern refinement. The architec¬ ture of Venice, Florence, Genoa, Rome and Sicily, afford to the architect a complete library of ex- 245 ITALIAN ARCHITECTURE. ITA amples by the possession of the several works published of the ar¬ chitecture of the palaces and man¬ sions of these cities. Respecting buildings originally erected in Italy, Mr. Jos. Gwilt has thus written:— The Romans followed the Greeks in the general form of their temples, but added to their splendour by a greater richness of detail, and the employment of other orders. For the simple steps ori which the Greek temple was elevated, they substi¬ tuted pedestals, and added a base to the Doric order. The climate pre¬ scribed a more elevated pediment; but the luxury of the people was the cause of the preference given to the richer orders of architecture. TEMPLES, BRIDGES, AQUEDUCTS, COLUMNS, THEATRES, ETC. The chief temples of Rome were —the Capitol, built on the Tar- peian or Capitoline mount, by Tar- quinius Superbus. (See Capito- limn.) No traces of it at present remain. The edifice of the Capitol was about 200 feet square, and con¬ tained three temples, consecrated to Jupiter, Minerva, and Juno. On the Capitol were also the temples of Terminus and Jupiter Feretrius, and the cottage of Romulus. The Pantheon, built by Agrippa, the son-in-law of Augustus, and dedicated to Mars and Venus, or more probably, from its name, to all the gods. Pope Boniface IV. consecrated it in honour of the Vir¬ gin Mary and All Saints, a.d. 607. It is now generally known by the name of the 1 Rotunda ; ’—its dia¬ meter between the axes of the columns is 147 feet: like most of the ancient buildings, it has fallen a prey to the spoiler. The Balda- chino in St. Peter’s is indebted for its materials to the Pantheon of Agrippa. The temple of Apollo, on the Palatine hill, was built by Augus¬ tus : a temple of Diana stood on the Aventine. ITA The temple of Janus was sup¬ posed to have been built by Romu¬ lus ; that of Romulus by Papirius. Of those to the Sun and Moon, Fortuna Virilis, Vesta, Minerva Medica, Neptune, Antoninus and Faustina, Concord, Jupiter Stator, and most particularly of the tem¬ ple of Peace, considerable remains are fortunately still in being. The three magnificent arches now stand¬ ing of that last named, though of themselves majestic, convey but a faint idea of its pristine splendour. Of the temple of Jupiter Stator, whose columns, capitals, and en¬ tablatures were a perfect example of the Corinthian order, only three columns are in existence. The re¬ mains of the temples of Antoninus Pius, Claudius, Hercules, Jupiter Tonans, Isis, Romulus, and Venus and Cupid, are still interesting. No vestiges exist of the temples dedicated to Saturn, Juno, Mars bis Ultor, in the forum of Augus¬ tus, nor of numberless others that adorned the city. The temples of Balbec and Pal¬ myra are the last of the ancient Roman works that can lay claim to the appellation of classic architec¬ ture. In these, invention seems to have found its limits. The repro¬ duction and new adaptation of their detail is all that has been done by following artists. The Romans, not content with the quadrilateral temple, made use of the circular form, as in the Pan¬ theon, temple of Vesta, and others at Rome, and that of the Sibyl at Tivoli. Except their theatres, and the little work generally known by the name of the Lantern of Demo¬ sthenes, the Greeks have left no buildings on a circular plan. After the time of Diocletian, a new style prevailed in Italy. The basilicae of Constantine, as they ex¬ isted previous to their restoration, and, in short, almost all the first Christian churches, were built out of the materials which the old tern* 246 ITA ITALIAN BUILDINGS. ITA pies afforded in abundance. The basilica of S. Paolo fuori le Mura still contains a large portion of the columns which had originally be¬ longed to the mausoleum of Adrian. The style of these basilic® may with propriety be termed Roman- Gothic. This was followed by the Greek-Gothic, of which examples may be found in most of the cities of Italy, as in St. Mark at Venice, the cathedral at Pisa (built by Buschetto da Dulichio, a Greek ar¬ chitect of the 11th century), and in the baptistery and leaning cam¬ panile of the same city : specimens abound also in Bologna, Siena, Ve¬ nice, Viterbo, Rome, etc. They are chiefly the works of Nicola da Pisa and his scholars. At the time that the famous ca¬ thedral of Milan, the perfection of the Lombard-Gothic style, was in hand, Brunelleschi was advancing a step further, and had begun the restoration of classical architecture in the great cupola of Sta. Maria del Fiore at Florence; his prototype seeming to have been the temple of Minerva Medica, to which his work has sufficient resemblance to justify the allusion to it. He suc¬ ceeded in bis enterprise, and thus gave a death-blow to the Italian- Gothic of all sorts. L. B. Alberti, Bramante, and Fra Giocondo re¬ stored the use of the orders; Michael Angelo, Raphael, Sangallo, Pal¬ ladio, and Scamozzi completed the change; the church of St. Peter rose, and every little city began to provide itself with a Duomo. The fora of the ancients were large squares surrounded by por¬ ticoes, which were applied to dif¬ ferent purposes. Some parts of them answered for market-places, other parts for the public meetings of the inhabitants, still other parts for courts of justice. The forum also occasionally afforded accom¬ modation for the shows of gladi¬ ators. Rome contained seventeen fora, of which fourteen were used for the show and sale of goods, provisions, and merchandise, and were called Fora Venalia; the other three were appropriated for civil and judicial proceedings, and hence called Fora Civilia et Judicialia. Of the latter sort was the forum of Trajan. The forum of Julius Caesar was far more splendid than the Forum Romanum: it cost upwards of .£800,000 sterling, and stood in the neighbourhood of the Campo Vaccino, to the east of the temples of Peace and of Antoninus and Faustina. In the vicinity of that last named was the forum of Augustus: the temple of Mars bis Ultor decora¬ ted the centre of it. The forum of Nerva, called also the Forum Transitorium, begun by Domitian, was decorated by Alex¬ ander Severus with colossal statues of the Emperors, some of which were equestrian. Parts of thisforum are still in tolerable preservation. The forum of Trajan, which has lately been accurately traced by means of veryextensiveexcavations, and the demolition of a great num¬ ber of houses, was by far the most magnificent. The Trajan column formed one of its ornaments : the architect was Apollodorus, and its situation was between the forum of Nerva and the Capitol. The basilica (a term now applied to the cathedrals of Rome) was originally a court of justice. Like the forum, it was furnished with shops for the merchants and bank¬ ers. In the place called the Comi- tium were four basilicse, viz. that of Paulus, the Basilica Opimia, Julia (built by Vitruvius), and Por¬ tia: besides thp .e, the most impor¬ tant were those of Sicinius, Sem- pronius, Caius and Lucius, Antoni¬ nus Pius, and the Basilica Argen- tariorum, or of the goldsmiths. Some of less consideration stood in the vicinity of the Forum Ro¬ manum. 247 ITA ITALIAN BUILDINGS. ITA The modern halls of Italy in some respects answer the purpose of the ancient basilicae. Those most worthy of notice are at Venice, Vicenza, Padua, and Brescia. Near the Tarpeian rock stood the famous prison built by Ancus Martius, which was afterwards call¬ ed Tullianum, from the additions thereto by Servius Tullius. The Curia Hostilia, where the Senate frequently met, was the Comitium : at its entrance, close to the tem¬ ple of Saturn, was the Milliarium Aureum, the central point from which all the roads to the different provinces diverged, and near to which ran the gallery constructed by Caligula, which joined the Pa¬ latine and Capitoline hills. It was constructed with eighty columns of white marble. The porticoes of Pompey, Au¬ gustus, Domitian, and Nero were the most celebrated of Rome. The first-named afforded a refreshing retreat from the sun’s rays. The portico of Augustus was construct¬ ed with columns of African mar¬ ble, and was ornamented with fifty statues of the Danaides. Those of Nero, three in number, each three miles in length, were called Milliariae, on account of their ex¬ traordinary dimensions, forming a part of his palace. The pyramidal form was gene¬ rally applied to tombs. In the he¬ roic ages, a cone of earth, whose base was of considerable extent, covered the ashes of the person to : be commemorated. This was the practice of the early ages. Men were, however, desirous of triumph¬ ing over death, and the Pyramids, as well as numberless other monu¬ ments, the names of whose authors are now lost, have proved the vanity of their desires: the memory of man must depend upon “ deeds done in the flesh.” The pyramid of Caius Cestius, a trifle compared with those of Egypt, is yet enormous, considering the in¬ dividual to whose memory it was erected. The tower of Cecilia Me- tella, called the Capo di Bove, on the Appian way, is a beautiful speci¬ men of art. The Appian, Flami- nian, and Latin ways exhibit num¬ berless sepulchres of an interest¬ ing nature. Those which are found with the inscription D.M., or Diis Manibus, contain the ashes of the persons whose names they bear; but the others are mostly cenotaphs, the bodies having been deposited elsewhere. Triumphal arches may be rec¬ koned among the luxuries of the Romans. Nothing which could tend to perpetuate the fame of the con¬ queror was omitted in the design. Some of them were with two, some with three passages. The richest were on the Triumphal way. Those which also served as gates generally consisted of two openings, one for the carriages passing out of, the other for carriages passing into the city. With the Greeks, a trophy erected on the field of battle was held of equal importance with the triumphal arch of the Romans, and a breach was sometimes made in the walls to admit the entry of the conqueror. The Roman Senate received the conqueror at the Porta Capena, near the Tiber, which was the en¬ trance to the city from the Appian way. The arch of Augustus at Rimini has but a single passage, about 33 feet wide: it was crowned with a pediment, contrary to the usual practice. This was a beautiful spe¬ cimen, but it is much mutilated. That called the arch of the Gold¬ smiths at Rome is a curious exam¬ ple. It is very small, with a single opening, whose crowning is a flat lintel. The arch of Augustus at Susa, a small town just on the Italian sideof Mount Cenis,is extremely elegant. Those of Aurelian and Janus are more singular than beautiful. 248 ITALIAN BUILDINGS. ITA The arch of Pola in Istria is only curious on account of its affording a justification of the use of coupled columns, were the authority of the ancients necessary for the purpose: it was erected by Salvia Posthuma in honour of Sergius Lepidus and his two brothers. The arch of Trajan at Ancona is still in tolerable preservation. It has long since been stripped of its bronze ornaments, but their absence has not impaired its elegant pro¬ portions. The arches of Titus at Rome ' and Trajan at Benevento bear con¬ siderable resemblance to each other. That of Gavius at Verona, called ‘ del Castel Vecchio,’ no longer ex¬ ists. The precepts of Vitruvius have been confronted with his prac¬ tice in this arch; but Vitruvius Cerdo, not Vitruvius Pollio, was the architect. The arches of Septimius Severus and of Constantine are with three openings. The latter is decorated with ornaments shamefully stripped otf from the arch of Trajan, which from their absurd application, ren¬ der the barbarism of the robber more disgusting. Rome formerly contained eight bridges. The Pons Sublicius, built by Ancus Martius near the Tiber, was of timber, so framed as to re¬ quire no iron bolts or ties for its security. It stood at the foot of the Aventine, and was that which Horatius Codes defended. It was replaced by one of stone by ^Emilius Lepidus, and then had the name of iEmilianus. Tiberius afterwards repaired it. Finally, Antoninus Pius rebuilt it of marble, whence it obtained the name of Marmoratus. The Pons Triumphalis, near the Vatican, is in ruins: few vestiges of it exist. Those who triumphed passed over this bridge in their way to the Capitol. The Pons Fabricius led to an island in the Tiber: it is now called Quattro Capi. That which led ITA from the island to the right bank of the river was called Pons Cestius or Esquilinus : it was rebuilt during the reigns of the emperors Valen- tinian, Valens, and Gratian. Pons Janiculi, so called because it led to the Janiculum, and now known by the name of Ponte Sisto (from having been restored by Six¬ tus IV.), was of marble, and built by Antoninus Pius. Pons iElius, built by iElius Adri- anus, is still in existence. It is situated close to the mausoleum of Adrian. This having changed its name into that of Castel St. Angelo, the bridge has acquired a corre¬ sponding appellation. The Pons Milvius, now Ponte Molle, is a little way out of the city, on the road to Florence. On this bridge Cicero arrested the ambas¬ sadors of the Allobroges, and in its vicinity Constantine defeated Max- entius. Pons Senatorius, or Palatinus, is partly remaining, close to the Pa- tine mount, Ponte Salaro is over the Teve- rone, about three miles from Rome. The spans of the arches are gene¬ rally but small; yet there are some few magnificent exceptions, as in the Ponte del Castel Vecchio at Verona. This consists of three arches, the largest of which is 170 feet span ; its two other arches are smaller: they diminish from the city, the left bank of the river being considerably lower than the right. The bridge built by Augustus over the Nar, near Narni, on the Flami- nian way, was a single arch of 150 feet span. In the later times of the city, bridges were decorated with trophies, colossal statues,triumphal arches, and the like. Such was the case with the Pons jElius and the bridge of Augustus at Rimini. The country round Rome is co¬ vered with the remains of aque¬ ducts, some of which conveyed the water to Rome from a distance of more than 60 miles. ITALIAN BUILDINGS. ITA The first aqueduct (Aqua Appia) was built, according to Diodorus, by Appius Claudius, in the year of the city 441. The water which it supplied was collected from the neighbourhood of Frascati, and its summit was about 100 feet above the level of Rome. The second (Anio Yetus) was begun forty years after the last- named, by M. Curius Dentatus, and finished by Fulvius Flaccus : it was supplied from the country beyond Tivoli. Near Vicovaro it is cut through a rock upwards of a mile in length, in which part it is 5 feet high and 4 feet wide. The water of this aqueduct was not good, and therefore only used for the most ordinary purposes. The third (Aqua Martia) was supplied from a fountain at the ex¬ tremity of the mountains of the Peligni. The water entered the city by the Esquiline gate. This aqueduct was the work of Quintus Martius. The fourth (Aqua Tepula) was supplied from the vicinity of Fras¬ cati. The fifth (Aqua Julia) was about six miles long, and entered the city near the Porta Esquilina. The sixth (Aqua Virginis) was constructed by Agrippa thirteen years after that immediately pre¬ ceding. Its summit, in the terri¬ tory of Tusculum, was about eight miles from Rome, which it entered by the Pincian gate. This water still bears its ancient appellation, being called Acqua Vergine. The seventh (Aqua Alsietina, called also Augusta, from the use to which Augustus intended to ap¬ ply it for supplying his Naumachia) was brought from the lake whose name it bears. The eighth (Aqua Claudia), whose summit is about forty miles from Rome, was begun by Caligula, and completed by Claudius. It enters the city at the Porta Nevia, near the Esquiline mount. The quality ITA of the water which this aqueduct supplies is better than that of any of the others. The ninth (Anio novus, to dis¬ tinguish it from the second-named water) was begun and finished by the same persons as the last-men¬ tioned. It is the water of the Anio, which, being exceedingly thick and muddy after the rains, is conveyed into a large reservoir at some little distance from Rome, to allow the mud to subside. The Acqua Felice is modern, and was erected by Sixtus V. in 1581. The Popes have, from time to time, been at considerable pains and expense in repairing and re¬ newing the aqueducts; but the quantity of water delivered is con¬ stantly diminishing. In the ancient city, the total sum of the areas of the different pipes (which were about an inch in diameter) through which the above immense quantity of water was delivered, amounted to about 14,900 superficial inches; but the supply was subsequently reduced to 1170. The waters were collected in re¬ servoirs called castella, and thence were conveyed through the city in leaden pipes. The keepers of the reservoirs were called castellani. Agrippa alone built thirty of these reservoirs during his sedileship. There are five modern ones now standing in the city : one at the Porta Maggiore, Castello dell’ Ac¬ qua Giulia, dell’ Acqua Felice, dell’ Acqua Paolina, and that called the Fountain of Trevi. In later times, the bath was al¬ ways used by the Romans before they went to their supper. The rich generally had hot and cold baths in their own houses ; and it was not till the time of Augustus that the baths assumed an air of grandeur and magnificence. They were called Thermae, that is, hot baths, though the same pile of building always contained cold as well as hot baths. Different au- 250 ITA ITALIAN BUILDINGS. ITA thors have reckoned as many as 800 public baths in Rome. The chief were those of Agrippa, Nero, Titus, Domitian, Caracalla, Anto¬ ninus, and Diocletian. Their ves¬ tiges indicate the amazing magnifi¬ cence of the age in which they were erected. The pavements were mosaic, the vaulted ceilings were gilt and painted, and the walls in- crusted with the richest marbles. Some of the finest and best pre¬ served remains of ancient Greek sculpturehave been restored to light xfrom these edifices.. It was from these that Raphael took the hint for his fantastic decorations of the Vatican, and the first restorers of art drew their resources. Dramatic entertainments were first introduced at Rome in the 391st year of the city. In ancient times the people stood during the performance. For a considerable period the theatres were mere tem¬ porary buildings constructed of wood. The most splendid of these upon record was that of Marcus iEmilius Scaurus : it was magnifi¬ cently decorated, and was capable of containing 80,000 persons. It was in Pompey’s second con¬ sulship that the first stone theatre was erected: this accommodated 40,000 spectators. To avoid the animadversions of the Censors (for the magistracy did not yet sanction theatrical exhibitions), he dedicated it to Venus. Several other theatres afterwards arose: that of Marcellus can still be distinctly traced, and part of the circular fagade, in tolerable pre¬ servation, is singularly elegant. The theatre of Balbus was also of considerable celebrity. The theatres were open at top to the heavens ; but in times of rain or excessive heat, means were pro¬ vided for covering them with a species of cloth awning, by which the inclemency of the weather might be wholly or partially exclu¬ ded. Their general form on the plan was that of the letter D. The seats ( gradus ) rose behind each other, like steps. The front row was as¬ signed for the use of the senators and the ambassadors of foreign states. Fourteen rows behind this were reserved for the equites, and the rest were open for the public generally. The beautiful Olympic theatre, by Palladio, at Vicenza, was formed on the model of the ancient Roman theatres, and gives one an excellent idea of their effect. Like the theatres, amphitheatres w r ere at first constructed of wood, and w'ere only temporary. The first amphitheatre of stone was built by Statilius Taurus, at the desire of Augustus. Of all the monuments of anti¬ quity, none is capable of creating such sublime sensations in the mind as the stupendous amphitheatre generally called the Coliseum. It was commenced in the time of Vespasian, and completed by Titus. The plan of it is oval, and its ac¬ commodation was for 87,000 spec¬ tators, who could enjoy the exhibi¬ tions therein without crowdingeach other. The part in which the gladi¬ ators fought was at the bottom, and was called the arena, from being usually covered with sand to absorb the blood spilt in the savage con¬ flicts for which it was used. The arena was encircled by a wall, called the podium, which projected at top. The podium was fifteen or sixteen feet in height: immediately round it sat the senators and foreign am¬ bassadors. As in the theatres, the seats rose at the back of each other : fourteen rows in the rear of the podium being allotted to the equites, and the remainder to the public generally, who sat on the bare stone ; but cushions were pro¬ vided for the senators and equites. Though open to the sky, the build¬ ing was occasionally covered by means similar to those used in the theatres. 251 -- — - - - -——— —— — -— — ITA ITALIAN BUILDINGS. ITA The amphitheatre at Verona is still in excellent preservation. The Naumachise, or buildings for the exhibition of sham naval com¬ bats, were somewhat similar on their plans to the circi, to which purpose also sometimes these latter were appropriated. The amphithe¬ atres were, moreover, occasionally used for the same sort of display. Those of Augustus and Domitian were the most magnificent. The circus was a long narrow building, whose length was to its breadth generally as five to one: it was divided down the centre by an ornamented barrier, called the spina. These buildings were used for the celebration of games, racing, etc., sometimes also for making harangues to the people. The first circus of stone is attri¬ buted 1) Tarquin, and was situated between the Palatine and Aventine mounts. The Circus Maximus was much improved and altered by Julius Caesar, who supplied it with w'ater for the purpose of occasionally using it as a naumachia. Augustus made great additions to it, deco¬ rating it with the famous obelisk w’hich now stands in the Piazza del Popolo, where it was placed by Fontana in the year 1589, during the pontificate of Sixtus V. Being much dilapidated, it was repaired under Antoninus, and afterwards embellished with a second obelisk, which has found a resting-place in front of the church of St. John Lateran, where it was set up by the same Fontana. No vestiges of this circus remain. The circus of Flaminius, in the vicinity of the Pantheon of Agrippa, was of considerable dimensions, and very magnificent. The Circus Agonalis occupied the site of what is now known by the name of the Piazza Navona. The circus of Nero, upon a part 1 whereof some portion of the basi¬ lica of St. Peter is seated, was a splendid building. The obelisk now standing in the open circular piazza -before St. Peter’s belonged to this circus. Those of Florus, Antoninus, and Aurelian, are no longer even in ruins ; but that of Caracalla is suf¬ ficiently perfect to trace its plan and distribution. It w T as 738 feet in length. The streets, in the time of Au¬ gustus, were narrow and irregular. After the great fire in Nero’s reign, the city was rebuilt with greater splendour. The streets w r ere then set out straight, and considerably broader than before. Those houses wherein several families dwelt were called insulas. Domus was the ex¬ pression for a house occupied by one family only. We know little of the form of the Roman houses, though Vitruvius has described at sufficient length the different apartments of which they consisted. The small houses discovered inthe ruins of Pompeii can bear but little if any resemblance to the houses of the opulent inhabitants of Rome. The most celebrated were those of the Gordians, P. Valerius Publicola, Caesar, Sallust, Mecaenas, Cicero, Verres, Augustus, and Lucullus. The Domus Aurea of Nero was probably the most magnificent in Rome. The villa of Adrian, at Tivoli, was so extensive, that it al¬ most deserved the name of a city. Immense ruins of the palaces of the Caesars are still to be seen. Rome was decorated with num¬ berless pillars. The most remark¬ able are fortunately in an excellent state of preservation, namely, those of Trajan and Antoninus. The column of Trajan stood in that emperor’s forum: it is about 12 feet in diameter at its base, and (including the pedestal) is about 125 feet in height. The ascent to the gallery on the top of the abacus of its capital is by 185 steps, each 2 feet 9 inches long, winding round 252 ITA ITALIAN ARCHITECTURE. ITA the column, and lighted by 40 open¬ ings. A colossal statue of Trajan formerly crowned the top ; but St. Peter has long since deposed the Emperor. The column of Antoninus is 176 feet high, its number of steps 106, with 56 openings for the admission of light. Sixtus V. caused its pe¬ destal to be cased, when, in 1589, the pillar was under repair. It was this pontiff who elevated St. Peter to his situation, as well on this as on the Trajan column. The great sewers of Rome are reputed to have been the work of Tarquinius Priscus. The Cloaca Maxima, which still carries some of the filth and w r aste water of Rome into the Tiber, was the work of Tarquinius Superbus. The public ways were not only some of the most stupendous, but also the most useful of the Roman works. The first road which the Romans paved was the Via Appia, so called because it was executed by order of Appius Claudius. He carried it as far as Capua, whence it was af¬ terwards continued to Brundusium —in all, a distance of 350 miles. It is still entire in many places, though more than twenty centuries have elapsed since its construction. It was properly called ‘ Regina Viarum.’ The Via Numicia led to Brindis (Brundusium); the Via Flaminia to Rimini and Aquileia ; the Via Aurelia was along the coast of Etruria ; the Via Cassia ran to Mo¬ dena, between the Flaminian and Aurelian ways; the Via TEmilia extended from Rimini to Piacenza. The smaller ways were, the Via Praenestina to Palestrina (the an¬ cient Praeneste); Tiburtina to Ti¬ voli ; Ostiensis to Ostia ; Lauren- tina to Laurentum, south of Ostia; Salaria, etc. The cross-roads were called Diverticula. Italian architecture comprises so many diversities that it is hardly possible to affix to it anything like a precise character, except by limit¬ ing it to a particular epoch or school, or to one special class of buildings; and even then the ex¬ ceptions may be more numerous than the examples referred to as a standard. With many vices and defects, it possesses many excel¬ lences and recommendations, and a variety of resources, which render it capable of being turned to far greater account than hitherto has been done. But if on the one hand it affords much scope to the architect, it calls on the other for the exercise of discriminating taste, one that not only rejects what is positively bad, but is capable of re-combining all the better ele¬ ments of the style, so as to impart to them originality and freshness, without forfeiting what is valuable in and characteristic of the style itself, so that, instead of appearing contrary to its genius, the novel forms and effects that may be pro¬ duced shall seem to be beauties, which have merely been lying la¬ tent, and waiting for a discoverer to bring them to light. A style is to be judged of, not only retro¬ spectively by what it has produced, hut prospectively also, according to what it is capable of supplying. Nevertheless, so far from being at all encouraged, such view of the subject is kept out of sight as much as possible; and precedent is al¬ lowed to usurp such sway, that any departure from it, no matter in what spirit, is liable to be con¬ founded with and reprobated as capricious innovation, although the one proceeds quite in an opposite direction to the other. Italian church (the), in the front or fafade, is never true to the internal structure; it is always divided into two apparent stories, by two heights of pillars, or pilasters, and by win¬ dows, or alcoves; but the greater number of churches in Rome have the outward look of large dwelling- 253 IVORY. ITA houses, a highly ornamented centre, and wings less so, with two or three ranges of windows, not differing from a habitable house. Italian varnish , for painting, is pre¬ pared by incorporating over a slow fire two parts of linseed or nut oil with one part of litharge, ground fine. The mixture must be fre¬ quently stirred to quicken the operation. Ivory is first mentioned in the reign of Solomon : ivory was used in de¬ corating those boxes of perfumes whose odours were employed to exhilarate tne King’s spirits. It is probable that Solomon, who traded Jack, an instrument for raising a heavy weight through a short dis¬ tance ; it consists of a strong piece of wood, with an iron rack which is moved, by wheels fixed inside the wood, from a handle outside. Jack, in navigation, a flag or colour; a small union flag. Jak-wood, a native of India, is im¬ ported in logs from 3 ft. to 5 ft. diameter; the grain is coarse and crooked: used in cabinet-work, marquetry, and turning, and also for brush-backs. Jamb, in building, a supporter on either side, as the posts of a door. Jambs, the side pieces of any open¬ ing in a wall, which bear the piece that discharges the superincumbent weight of such wall. Janta, a machine extensively used in Bengal and other parts of India, to raise water for the irrigation of land. It consists of a hollow trough of wood, about 15 ft. long, 6 inches wide, and 10 inches deep, and is placed on a horizontal beam lying on bamboos fixed in the bank of a pond or river: one end of the trough rests upon the bank, where a gutter is prepared to carry off the water, and the other end is dipped in the water by a man standing on JET in India, first brought thence ele¬ phants and ivory into Judaea. Ca¬ binets and wardrobes were orna¬ mented with ivory by marquetry- work. These were called ‘ houses of ivory.’—“ Eighty more chests of ivory, for your use and plea¬ sure,” are enumerated in the letter which accompanied the very re¬ markable tribute of the Ethiopian queen, Candace, to Alexander the Great. Ivory-black and bone-black, ivory and bone charred to blackness by strong heat in closed vessels; if skilfully prepared, they are eligible for oil and water painting. a stage, plunging it in with his foot. Janua, among the Romans,the street- door of a private house. Japanning, the art of painting and varnishing on wood, leather, metal, or paper, after the manner of the Japanese. Jasper is found along the shores of the Bay of Chaleur, and other lo¬ calities in the northern part of New Brunswick. Jaune mineral. This pigment is a chromate of lead, prepared in Pa¬ ris. The chrome-yellows have ob- ] tained other names from places or persons from whence they have ] been brought, or by whom they have been prepared, such as Jaune de Cologne, etc. Jesse (the root of), a term applica¬ ble to the genealogy of Christ, as I affording subjects for the painter, | I sculptor, or embroiderer. Jet d'eau, a French expression, sig- , nifying a fountain that throws up water to some height in the air. Jetty, a part of a building that pro¬ jects beyond the rest, and over¬ hangs the wall below, as the upper j stories of timber houses, bay-win- j dows, pent-houses, small turrets at | the corners, etc. JOINERY. JET KEE Jetty, a projecting erection into the sea, partaking something of a pier, mostly constructed of timber, with open spaces for the sea to play. Jewry, a district, street, or place or locality, in which Jews formerly resided. Jib, the overhanging part of a crane, or a triangular frame with a pulley at the end, for the chain to pass over which leads from the crane. Jib, in navigation, the foremost sail of a ship. Jib-boom, a spar run out from the bowsprit. Jigger, a machine consisting of a piece of rope about 5 feet long, with a block at one end and a sheaf at the other, used to hold on the ca¬ ble when it is heaved into the ship by the revolution of the windlass. Jigging, in Cornwall, a method of dressing the smaller copper and lead ores, by the motion of a wire sieve in a kieve or vat of water. Joggle, a term in masonry, the art of joining and fitting the stones to¬ gether. Joinery, the art of joining, compre¬ hends all the fixed woodwork in¬ tended for ornament or conveni¬ ence in the interior of a house. Joint, the interstices between the stones or bricks in masonry and brickwork are so called. Joists, in carpentry, the secondary beams of a floor; those pieces of timber framed into girders and Kage, anciently applied to chantry chapels enclosed with lattices or screenwork. Kaolin, aluminous earth ; the porce¬ lain earth of the Chinese. Kazer, in Cornwall, a sieve. Kedging, in navigation, a term used when a vessel is brought up or down a narrow river or over a bar. Keel {False), in ship-building, a strong thick piece of timber bolted to the bottom of the real keel, which is very useful in preserving it. summers, on which the boards of the floor are laid. Journal, a bearing of a shaft when it is between the points where the powers and resistance are applied; a bearing subject to torsion. Jube, anciently, the rood-loft or gal¬ lery over the entrance into the choir of a cathedral or church. Jugumentum, the lintel of a door. Jumper, a long borer used by one person. Juniper wood, an aromatic and very durable kind of wood. Junfc, an Indian or Chinese ship. Junk-ring, a ring fitting a groove round a piston, to make it steam- tight. The ring is turned accu¬ rately to the diameter of the cylin¬ der, and slightly hammered all round on the inside to increase its elasticity; it is then cut open, and put in its place : springs are some¬ times used for pressing it outward. Justice {Courts of). These places, according to Palladio, were an¬ ciently called Basilicae, where the judges attended to administer jus¬ tice, and where, sometimes, great and important affairs were trans¬ acted : whence we read, that the tribunes of the people caused to be taken away a column that inter¬ rupted their benches, from the Ba¬ silica Portia; which was at Rome near the temple of Romulus and Remus, and is now the church of St. Cosmus and Damianus. Keels, in navigation, small vessels that carry coals down the river Tyne. Keelson, in ship-building, the piece of timber attached to a ship’s keel. Keep, the chief tower or dungeon of a Norman castle. Keeping, in painting,is the observance of a due proportion in the general light and colouring of a picture, so that no part be too vivid or more glaring than another, but a proper harmony and gradation be evident in the whole performance. 255 KEP KEY-STONE. KNI Kept down is a term implying gloomi¬ ness of tint, or an object so shaded with fuscous colour that its form can scarcely be determined; which object is not intended to be seen by the spectator until he has re¬ gularly observed all the other parts of the painting, but which is ne¬ cessary to the composition. Kermes lake, an ancient pigment, per¬ haps the earliest of the European lakes : the name is probably derived from the Alkermes of the Arabians, from Kerman, the ancient Carma- nia, on the borders of Persia. Kerned, a term applied to a heap of mundic or copper ore hardened by lying exposed to the sun. Ketch, in navigation, a vessel with masts and sails. Kevels, in ship-building, answer the purpose of timber-heads, and are sometimes fixed to the spirketing on the quarter-deck, when the tim¬ ber-heads are deficient. Key, a term applied to a painting when one object, generally the prin¬ cipal one, is so worked up to its proper tone, strength of colour, etc., that the painter is compelled to finish the whole piece in a mas¬ terly manner: this is said to have been the practice of Titian. Key-grooving machine, a machine for cutting the grooves or key-ways in the boss of a wheel to be fixed on a shaft. Key-screw, a lever used for turning screws. Key-stone, the stone in an arch which is equally distant from its springing extremities. In a circular arch there will be two key-stones, one at the summit and the other at the bottom thereof: in semi-circular, semi-elliptical arches, etc., it is the highest stone, frequently sculp¬ tured on the face and return sides. Kiabooca-wood, or Amboyna-wood, imported from Singapore, is very ornamental, and is used for small boxes and writing-desks. Kibbal, a bucket in which ore is raised from the mines. Kieve, a vat or large iron-bound tub for washing of ores. Kilkenny marble, a fine black marble, full of shells and corolloid bodies. Killas, a clay slate occurring in dif¬ ferent parts of a mine. Killepe, anciently a gutter, groove, or channel. Kiln, a furnace for burning bricks and tiles, also limestone or chalk, to make lime; a place for drying malt or hops. Kilogramme (pronounced Kilo), a French weight, equivalent to 2 lbs. 3 oz. 5drs. 13 grs. avoirdupois. King-at-arms, in heraldry, a principal officer at arms. There are three: Garter, Norroy, and Clarencieux. King-post, the middle post of a roof, standing in the tie-beam and reach¬ ing up to the ridge; it is often formed into an octagonal column with capital and base, and small struts or bases, which are slightly curved, spreading from it above the capital to some other timbers. Kingston's valve, a flat valve forming the outlet of the blow-off pipe of a marine engine: it opens from the side of the vessel by turning a screw. King-wood, called also violet-wood, is imported from the Brazils: it has violet-streaked tints, and is used in turnery and small cabinet-work. Kirk, church, a term still used in Scotland, formerly so in England. Klinometer, or Clinometer, an instru- ^ ment contrived to measure the in¬ clinations of stratified rocks, the declivity of mountains, and the dip of mineral strata. Knee, a term sometimes used for the return of the drip-stone at the spring of an arch. Kneller (Sir Godfrey), flourished dur¬ ing Charles II.’s reign. Knees, in ship - building, are the crooked pieces of oak timber, or iron, which secure the beams to the side of the ship. Knight-heads or bollard-timbers, the timbers on each side nearest the | stem, and continued high enough ! J to secure the bowsprit. KYAN1ZING. KNI KYA Knits, small particles of lead ore. KnocJcings, lead ore with spar, as cut from the veins. Knot or Knob, a boss; a round bunch of leaves or flowers, or other orna¬ ment of a similar kind. Knuckle-timber, the foremost top timber in the ship that forms the buck-head; the timbers abaft it, as far as the angle is continued, may be called knuckle-timbers. Krems, Crems, or Kremnitz white, a white carbonate of lead, named from Crems or Krems, in Austria; also called Vienna white. Kyanizing and Burnettizing. Kyani- zing is a simple process by means of which timber, canvas, and cord¬ age, etc., may be preserved from the effect of dry-rot, and seasoned in a very short time. It was in¬ vented by Mr. Kyan, who obtained a patent for it, which was purchased by a Company called the ‘ Anti- Dry-rot Company,’ constituted and empowered by Act of Parliament. The timber is prepared as fol¬ lows : a wooden tank is put together so that no metal of any kind can come in contact with the solution when the tank is charged. The solution consists of corrosive subli¬ mate and water, in the proportion of 1 lb. of corrosive sublimate to 10 gallons of water as a maximum strength, and 1 lb. to 15 gallons as a minimum, according to the poro¬ sity or absorption of the timber subjected to the process. Oak and fir timber absorb nearly alike, but the domestic woods, such as beech, poplar, elm, etc., are more porous. An hydrometer will mark accu¬ rately the strength of the solution, ■water being0 {vide diagram); then, when the hydrometer sinks to 6°, it denotes that the solution con¬ tains 1 lb. of sublimate to 15 gallons of water; when it rises to 17°, 1 lb. of sublimate to 5 gallons. As a general rule, when it stands midway between 5° and 10°, the solution will be the proper strength. 257 The corrosive sublimate will dis¬ solve best in tepid water. Water. y— 1 lb. of cor. sub. to J 15 gal. of water. -1 lb. to 10 gal. do. 1 lb. to 5 gal. do. A o The period required for satu¬ rating timber depends on its thick¬ ness : 24 hours are required for each inch in thickness, for boards and small timbers. The timbers, after saturation, should be placed under a shed or cover from the sun and rain, to dry gradually. In about 14 days, deals and tim¬ ber not exceeding 3 inches in thick¬ ness will be perfectly dry and sea¬ soned, and fit for use. Large timbers will require a proportionate time, according to their thickness. The solution may be used ad infinitum, as its strength is not diminished ; but it will be advisable to ascertain occasionally by the hydrometer that it contains the re¬ quired proportions of corrosive sub¬ limate and water. Professor Faraday and the late Dr. Birkbeck have, with many other scientific men, testified in the strongest manner to the efficacy of this solution. The former says, with respect to the penetration of the solution by steeping, without KYA KYANIZING AND BURNETTIZING. KYA pressure, that it may be tested by the application of a drop of hydro- sulphuret of ammonia, which will turn black on meeting with the mercury. In the cube of elm, the corrosive sublimate may be traced by the above test to the depth of from £ to £ of an inch; by the test of voltaic action, from f to 1 inch. In the cube of oak, with the same test, it was found at i of an inch, hut irregular, and apparently fol¬ lowing the fissures of the wood; by voltaic action, not quite so far as in the elm. In the cube of fir, the penetra¬ tion was the least by the common test, ^ to ^ of an inch : by voltaic action, ^ of an inch, the turpentine in the wood probably being the obstruction to penetration. From this testimony it is evident that when pressure is not used, the timber should be worked up into the form required before immer¬ sion. The patentees or Company, who have also the means of saturating with hydraulic pressure at their establishment, similar to that at Portsmouth Dockyard, under Sir William Burnett’s process, grant licenses at the rate of 5s. per cubic foot, internal dimensions of the tank, and sell corrosive sublimate at 4s. per lb. 1 lb. is sufficient to saturate a load of timber of 50 cubic feet, at the rate of 1 lb. of sublimate to 15 gallons of water.. The process has been for several years extensively used for sleepers on railroads. Several of the sleepers on the South-western Railway, which had been subjected to this process, were taken up, owing to their being decayed, particularly in the chalk districts. It was, however, stated by the engineer that they had been steeped at the Company’s works in a hasty manner, and that he did not consider it conclusive against the process ; that he had never seen any wood decayed that had been steeped by the patentees. It is also said that neither Kyan’s, Burnett’s, nor Payne’s process, can resist the combined effects of mois¬ ture and great heat, say 80° Fahr. BURNETTIZING. Burnettizing is the process by means of which timber, felt, can¬ vas, cordage, cottons, and woollens, may be preserved from dry-rot, mildew, moth, and premature de¬ cay. It takes its name from its inventor, Sir William Burnett, M.D., K.C.B., F.R.S., of the Navy, who took out a patent for it in 1837. It consists in immersing the va¬ rious substances above enumerated in a solution of chloride of zinc and water in a wooden tank, in the proportion of 1 lb. of chloride of zinc to 4 gallons of water for wood, and 1 lb. of the chloride to 5 gal¬ lons of water for the remainder of the articles, with the exception of felt, which requires 1 lb. of the chloride to 2 gallons of water. Three-inch deals require to re¬ main in the tank or cistern six days, and all other woods in the same proportion, or two days per inch. They are then taken out and put under a shed, on their ends, to dry, and require for this purpose from fourteen days to three months, according to the thickness of the wood, when they are fit for use. The timber should be reduced to the scantling required for use before it is subjected to this process. Canvas,yarn for cordage, cottons, and woollens, require to be sus¬ pended in the solution for forty- eight hours. The process, however, with re¬ spect to timber, is much more ex¬ peditiously and effectively done by hydraulic pressure in her Majesty’s dockyard at Portsmouth, where large quantities of timber, etc., are prepared for the use of the Royal Navy at the various dockyards in 258 KYA KYANIZJNG AND BURNETTIZING. KYA England, particularly for ships’ magazines. There is a large wrought-iron tank, 52 feet in length and 6 feet in diameter, with a door 2 feet 6 inches x 2 feet at each end for loading. Timber of all sizes and descrip¬ tions is put into this cylinder, which contains about twenty loads. As soon as it is filled, and the doors well secured both against external and internal pressure, the air is ex¬ hausted in the cylinder, and also in the timber, by means of an air- pump worked by a small rotatory engine of 10-horse power, on the Earl of Dundonald's principle, un¬ til the barometer stands at 27°: the valve leading to the air-pump is then shut, and the cock of a pipe leading from the tank, filled with the solution, to the cylinder, is turned: the solution rushes into the cylinder to fill up the partial vacuum, and about half-fills it, when the cock is turned, and the air-pump again set to work until the barometer stands at 27J°, when the same process is repeated, and the cylinder nearly filled with the solution. A pressure of 150 lbs. per square inch is then obtained by means of a Bramah forcing-pump, connected with an iron copper or reservoir, filled with the solution, and com¬ municating with the cylinder by means of a pipe. This is worked by hand until a valve placed on the top of the cylinder, and loaded to the required gauge, begins to lift. The timber is then left in the cylinder, subject to this pressure, for eight hours, which is considered sufficient for the largest logs, even in a rough state. The solution being then drawn off into the tank, and the timber taken out of the cylinder, it is re-loaded, and the process repeated: the same solu- . tion is used for two months, when fresh is prepared. The same process for drying the timber thus saturated is adopted, as before stated. Canvas, felt, and yarn, etc., are not subjected to pressure. The felt is used as a lining to the magazines of men-of-war, between two thicknesses of wood; also to cover over the steam-boilers of steam-ships: it is said to be ren¬ dered much less liable to combus¬ tion by the process. It is stated that in tropical cli¬ mates, more especially in Africa, the saturated canvas has stood the climate, when the unprepared, un¬ der similar circumstances, has ra¬ pidly decayed. Both Burnettizing and Kyani- zing offer great advantages to the engineer: 1st. Wood of every kind is ren¬ dered more durable, and is rapidly seasoned. 2ndly. It brings into general use larch, poplar, and a variety of other indigenous woods, as well as American pine, etc., which, with¬ out the process, from being liable to rapid decay, and being much inferior to Baltic timber, are sel¬ dom used in public buildings. To the military engineer, these inventions offer still greater advan¬ tages. He is frequently called on, in distant colonies, to construct block-houses, stockades, bridges, and barracks, where the only ma¬ terial to be had in abundance is the tree standing in the forest: to him a few pounds of either ingre¬ dient would be invaluable, by en¬ abling him to season and render durable the timber a few days after it was cut down, and thus provide him with the ready means of ren¬ dering a distant post tenable in a short time by a small body of men, w’ith the additional satisfaction of knowing that the work thus hastily erected would be found to be of a permanent nature. Kyste, a chest or coffin for the burial of the dead. 259 LAKE. LAB LAN L. Laburnum, a small dark-greenish broom-wood, is sometimes used in ornamental cabinet-work. Labyrinth, a series of hedges, mounds, or walls, with numerous winding passages; intricate and winding walks in a garden. Lacing, a piece of compass or knee- timber, fayed to the back of the figure and the knee of the head of a ship, and bolted to each. Lacker, or Lacquer, a varnish applied upon tin, brass, and other metals, to preserve them from tarnishing, and to improve their colour. Lac lake is prepared from lac, an Indian drug. It resembles cochi¬ neal and kermes, being the produc¬ tion of a species of insect. Its co¬ lour is rich, transparent, and deep, —less brilliant and more durable than those of cochineal andkermes, but inferior in both these respects to the colour of madder. Laconicum, among the ancients, the semicircular end of a bath; a cir¬ cular stove, for the purpose of heating the sudatories, or sweating- rooms of a bath : the use of the dry bath is said to have been pre¬ valent among the Lacedaemonians. Lacunar, an arched roof or ceiling, more especially the planking or flooring above the porticoes. Lacunaria, the ceiling of the ambu¬ latory around the cella of a temple or of the portico. The beams, which extended from the walls to the entablature, were intersected by others ranged longitudinally: the square spaces made by these intersecting beams were contracted towards the top, and were some¬ times closed with single stones, which might occasionally be re¬ moved. Lacunars, in architecture, are panels or coffers in the ceilings of apart¬ ments, and sometimes in the sof¬ fits of the corona of the Ionic, Corinthian, and Composite orders. 260 Lade, a passage of water, the mouth of a river. Lady-chapel, a chapel dedicated to J the blessed Virgin. Laines, courses laid in the building of walls. Lake (colour), a name derived from the lac or lacca of India, is the cognomen of a variety of transpa¬ rent red and other pigments of great beauty, prepared for the most part by precipitating coloured tinc¬ tures of dyeing drugs upon alumine and other earths, etc. The lakes are hence a numerous class of pig¬ ments, both with respect to the variety of their appellations and the substances from which they are prepared. The colouring mat¬ ter of common lake is Brazil wood, which affords a very fugitive co¬ lour. Superior red lakes are pre¬ pared from cochineal, lac, and kermes; but the best of all are those prepared from the root of the rubia tinctoria, or madder- , plant. See Lac lake. Lama, in mining, slime or schelm. Lamina, the extremely thin plates or layers of metal which compose the solid metal. Laminable, a term applied to metal which may be extended by pass- t ing it between steel or hardened (chilled) cast-iron rollers. Laminated, disposed in layers or plates. When metal can be readily extended in all directions, under the hammer, it is said to be mal¬ leable, and when in fillets under the rolling-press, it is said to be laminable. Lamp-black, a soot of resinous woods obtained in the manufacturing of tar and turpentine. It is a pure carbonaceous substance of a finei texture, intensely black and per-f fectly durable, which works well,j but dries badly in oil. I^ance wood, imported in long poles from 3 to 6 inches in diameter, LAN from Cuba and Jamaica, is of a paler yellow than box-wood: it is selected for elastic works, as gig shafts, archery bows and springs, surveyors’ rods, billiard cues, etc. Landscape. In landscape we find Na¬ ture employing broken colours in enharmonic consonance and variety, and equally true to picturesque re¬ lations : she employs also broken forms and figures in conjoint har- mony with colours, occasionally throwing into the composition a regular form or a primary. Landscape Gardening. The outline of a wood may sometimes be great, and always beautiful, but the first requisite is irregularity. That a I! mixture of trees and underwood should form a long straight line, can never be natural; and a suc¬ cession of easy sweeps and gentle rounds, each a portion of a greater or less circle, composing altogether a line literally serpentine, is, if pos¬ sible, worse; it is but a number of regularities put together in a disor¬ derly manner, and equally distant from the beautiful, both of art and of nature. The true beauty of an outline consists more in breaks than in sweeps; rather in angles than rounds; in variety, not in succes¬ sion. The outline of a wood is a continued line, and small variations do not save it from the insipidity of sameness: one deep recess, one . bold prominence, has more effect than twenty little irregularities; and that one divides the line into parts, but no breach is thereby made in its unity : a continuation of wood always remains, the form of it only is altered, and the extent increased: the eye, which hurries to the extremity of whatever is uniform, delights to trace a varied line through all its intricacies, to pause from stage to stage, and so lengthen the progress. The parts must not, however, on that account, be multiplied till they are too minute to be interesting, 261 LAN and so numerous as to create con¬ fusion : a few large parts should be more strongly distinguished in their forms, their directions, and their situations : each of these may afterwards be decorated with sub¬ ordinate varieties, and the mere growth of the plants will occasion some irregularity: on many occa¬ sions more will not be required. Every variety in the outline of a W’ood roust be a prominence or a recess; breadth in either is not so important as length to the one and depth to the other: if the former ends in an angle, or the latter di¬ minishes to a point, they have more force than a shallow dust or a dwarf excrescence, how wide so¬ ever : they are greater deviations from the continued line which they are intended to break, and their effect is to enlarge the wood itself. Every variety of outline hitherto mentioned may be traced by the underwood alone; but frequently the same effects may be produced with more ease, and much more beauty, by a few trees standing out from the thicket, and belonging or seeming’to belong to the wood, so as to make a part of its figure. The materials of natural land¬ scape are ground, wood, and water, to which man adds buildings, and adapts them to the scene : it is therefore from the artificial con¬ siderations of utility, convenience, and propriety, that a place derives its real value in the eyes of a man of taste : he will discover graces and defects in every situation ; he will be as much delighted with a bed of flowers as with a forest thicket, and he will be as much disgusted by the fanciful affecta¬ tion of rude nature in tame scenery as by the trimness of spruce art in that which is wild. Landscape Painting. The best paint¬ ers in landscape have studied in Italy or France, where the verdure of England is unknown: hence arises the habit acquired by the LANDSCAPE GARDENING. connoisseur, of admiring the brown tints and arid foregrounds in the pictures of Claude and Poussin ; and from this cause he prefers the bistre sketches to the green paint¬ ings of Gainsborough. One of our best landscape painters studied in Ireland, where the soil is not so yellow as in England; and his pic¬ tures, however beautiful in design and composition, are always cold and chalky. Autumn is the fa¬ vourite season of study for land¬ scape painters, when all nature verges towards decay, when the foliage changes its vivid green to brown and orange, and the lawns put on their russet hue : but the tints and verdant colouring of spring and summer will have su¬ perior charms to those who de¬ light in the perfection of nature, without perhaps ever considering whether they are adapted to the painter’s landscape. Land Steward. A person solely occu¬ pied in the management and culti¬ vation of an estate should see to ! the production, advancement, and value of the land; should be well l acquainted with the pursuits and interests of country life ; should un¬ derstand the qualities of the soil and the proper manuring of the same, as well as the different com¬ binations of sand, gravel, loam, clay, chalk; he should he able to show what stock the pasture will maintain, what quantity of grain the arable land will produce, and what quantity of hay may be ex¬ pected from the meadows : with other requisite knowledge pertain¬ ing to farming, he will be able to form a fair estimate of the produce of the farm, to keep accounts, and ultimately acquire a taste for the erection of farm buildings and la¬ bourers’ rural cottages, and also the arrangement of landscape, flower, and vegetable gardens. Laniard, in navigation, a stout piece of line or cord used to fasten and secure the shrouds, stays, or buoys. Lantern, in architecture, a small structure on the top of a dome or in similar situations for the admis¬ sion of light, and the promotion of ventilation. It is generally made ornamental, and was much used, in , Gothic and Tudor architecture. Lanzi (Abbate Luigi), the author of the ‘ History of Painting in Italy,’ was born in 1732 and died in'1810. .j Lapidarius, a lapidary, a stone-cutter. j Lapis lazuli, a mineral which fur¬ nishes the valuable pigment called ultramarine. Lapis lydius, a variety of touchstone ; the schistose jasper of Brongniart, containing silica, iron, alumina, and charcoal. Laque minerals is a Trench pigment, a species of chromic orange. This name is also given to orange oxide of iron. | Larboard, in navigation, the left-hand side of a ship, standing with face to the head : now the word ‘ Port’ is j used. Larch, a tree, larchwood, much grown by the Duke of Athol, in Scotland. There are three species, one Euro¬ pean and two American. Lardrose, a screen at the hack of a seat behind an altar. Later, a brick or tile. Besides the jj Greeks and Romans, other ancient nations employed brick for build- ; ing to a great extent, especially the |. j Babylonians and Egyptians. ; Lathed a machine for turning metals or wood by causing the material to revolve upon central points, and be cut by a tool fixed in a slide-rest, or held by hand. The lathe is very ancient, and seems to have been known to the Greeks and Romans, hut, till within the last half century, was a very | rough and almost powerless ma¬ chine compared with the elegant, very powerful, and well constructed machine now in use. It is used for turning either metal or timber, and varies in size and construction, ac¬ cording to the nature of the work required. 262 LAVER. LAT The construction of the present lathe is as follows : a long frame, called the lathe-bed, having a per¬ fectly planed surface, and a slot or mortise from end to end, is fixed at each end upon two short standards, and upon one end of it a frame, called the head-stock or mandril- frame, is bolted : this frame carries the short shaft or mandril, upon which are the driving pulleys. The end of the mandril stands through the inner side of the frame, and is screwed so that a socket or centre chuck may be fixed on it: this chuck acts as a centre for the work | to rest upon, and has a projecting arm or driver to carry it round with it. Another frame, called the back centre frame, capable of being fixed upon the lathe-bed at any distance from the front centre, has a cylin¬ der, with a pointed end or centre, at precisely the same height as the other, with two set-screws, one to adjust the centre piece, the other to fix it. The work is placed be¬ tween these two centres, and caused to revolve by a band passing over a pulley on the mandril, if the lathe is large, and by a treddle and band- wheel, if the lathe is small. In small lathes, the rest, upon which the tool is held, is fixed in a socket cast on a small slide by a 1 set-screw : the slide is for adjust¬ ing its position, and is capable of being fixed at any part of the lathe- bed between the centres. In large lathes the slide-rest is r always used. See Slide-rest. T Mthe-bed, that part of a lathe on which the ‘poppet-head’ slides forward or backward to its required position. ■atitude, breadth, width, extent; in ! geography, the distance, north or south, from the equator, a great circle, equally distant from the poles, dividing the globe into equal parts, north and south. atten, a mixed metal resembling brass. The monumental brasses in churches are called latten. Lattern-sail, in navigation, a long triangular sail used in xebecs, etc. Launders , in mining, tubes and gut¬ ters for the conveyance of water in mines, etc. Lavatory , a cistern or trough to wash in, used formerly in monasteries. Laver, brazen . Moses was directed to make, among other Articles of furniture, for the services of the ta¬ bernacle, a laver of brass, borne by four cherubim, standing upon bases or pedestals, mounted on brazen wheels, and having handles belong¬ ing to them, by means of which they might be drawn and conveyed from one place to another, as they should be wanted. These lavers were double, composed of a basin which received the water that fell from another square vessel above it, from which the water was drawn by cocks. The whole work was of brass: the square vessel was adorned with the heads of a lion, an ox, and a cherub. Each of the lavers contained forty baths, or four bushels, forty-one pints, and forty cubic inches of Paris measure. La y figure, a figure made of wood 01 cork, in imitation of the human body. It can be placed in any po¬ sition or attitude, and moves at every joint, on the principle of the ball and socket. It serves, when clothed, as a model for drapery and for foreshortening. The dress of the person is generally placed on the lav-figure after the head is taken, by which the painter finishes his entire portrait at leisure, with¬ out requiring the person to sit. Lazaretto, an hospital ship for the reception of the sick. Lead is a very heavy metal, suffici¬ ently well known. The mode of purifying it from the dross which is mixed with it, by subjecting it to a fierce flame, and melting off its scoria, furnishes several allusions in Scripture to God’s purifying or punishing his people. It was one of the substances used for writing upon by the ancients. ° LEA 263 LEA LEVELLING. LEV Lead spar, sulphate of lead. Leader, a branch, rib, or string of ore, leading along to the lode. Leading springs, the springs fixed upon the leading axle-box of a locomotive engine, bearing the weight above. Leading wheels, the wheels of a loco¬ motive Agine, which are placed before the driving wheels. Lease, holding of land or house for a term of years at a rent. Leaf, a water-course, or level for con¬ veyances of water. Leaves, a term applied to window- ( shutters, the folding-doors of clo¬ sets, etc. Leaving (in Cornish), or casualties, in tin, is the same as hanaways of copper or lead ore. Lectern or Lettem, the desk or stand on which the larger books used in the services of the Roman Catholic church are placed. In modern Protestant churches they are now often used, and are very ornamental in appearance, and far more ap¬ propriate than the cumbersome reading-desk. Lecterns are made sometimes of stone or marble, but usually of wood and brass, and generally are extremely well exe¬ cuted. Lectus, a bed or couch. Ledger, a large flat stone laid over a tomb : horizontal timbers used in forming scaffolding are also called ledgers. . Ledgment, a string-course, or hori¬ zontal suite of mouldings, such as the base-mouldings of a building. Lee, in navigation, the side opposite to the wind; as the lee-shore is that on which the wind blows. Lely (Sir Peter), flourished in Charles ll.’s reign. Lernbus, according to Plautus, a_skiff or small boat, used for carrying a person from a ship to the shore. Lemon yellow, a beautiful light and vivid colour. In body and opacity it is nearly equal to Naples yellow and masticot, but much more pure and lucid in colour and tint, and at ----- the same time not liable to change by damp, sulphurous or impure air, or by the action of light, or by the steel palette-knife, or by mixture of white lead or other pigments, either in water or oil. Lessee, one to whom a lease is given. Lessor, one who grants a lease. Levecel, anciently a pent-house, or a projecting roof over a window, door, etc. Level, an instrument for determining the heights of one place with re¬ spect to another. Levelling, the art by which the rela¬ tive heights of any number of points are determined. The height of a point is the vertical distance to which it is ele¬ vated or depressed, as compared with the true general surface of the earth. The earth is in form a spheroid. On land we can nowhere trace its true geometric surface ; but the sea, when at rest, presents every¬ where a verv near approximation to it, and hence the level of the sea has been assumed as the stan¬ dard to which all heights are to be referred. The absolute height, then, of any point is its vertical distance from the level of the sea: the relative height of two or more points, com¬ monly called their difference of level, is the difference of those vertical distances. A true level is any surface or line which is parallel to the true geometric surface of the earth; everv true level must, therefore, necessarily present a curve every¬ where perpendicular to the direc¬ tion of gravity. It is a beautiful property of fluids that in every situation, when at rest, their sui- face will present a true level. All points situated within the same true level are evidently at the same height. One point is said to be higher or lower than another, according as a true level traced through it passes 264 LIGHT. LEV above or below that point; and the vertical distance at which it so passes is the measure of its relative height. In theory, levelling is extremely simple. It consists in tracing through space a series of level sur¬ faces, and finding their intersec¬ tions with vertical lines passing through the points whose relative height we wished to ascertain. Level {Road), a triangular frame of wood with a long straight base, and a plummet suspended by a thread from the vertex of the triangle. When the ground to which it is applied is level, the thread will co¬ incide with a line perpendicular to the base. A tool similar in principle to the above-mentioned is used by fitters, and is made of a plate of sheet- iron, two sides of which form a right angle, and the thread which suspends the plummet is parallel to the vertical side when the base is level. Level {Spirit), a glass tube, closed at the ends, and nearly filled with water or spirits, fixed in a piece of wood or metal with a flat base, to which the tube is perfectly parallel. When placed upon a level surface, an air-bubble will be at the centre of the tube. Lever, the first mechanical power, being an inflexible straight bar, supported in a single point on a fulcrum or prop, called its centre Qf motion : it is used to elevate a great weight. Lever-valve, a safety-valve kept in its seat by the pressure of a lever with an adjustable weight. In locomo¬ tive engines a spring is used at the end of the lever, instead of the weight; and the pressure is regu¬ lated by a screw, and indicated on a brass plate. Levigation, the process of reducing hard bodies into subtile powder by grinding upon marble with a muller. Lewis, an instrument used by masons for hoisting, consisting of thin L!G wedges of iron, forming a dovetail, which is indented into a large stone for the purpose of moving it. Ley, a standard of metal; contents in pure metal. Libella, a small balance; a level used by carpenters and masons to test flat surfaces. Libra , a pound weight; a balance, or a pair of scales : one of the twelve signs of the zodiac. Library, a room or rooms appropria¬ ted for the arrangement and keep¬ ing of books, fitted up with shelves to hold them, or furniture called book-cases, to which shelves are affixed for the same purpose. Licli-gate, a gate belonging to church¬ yards. Lifting-gear, the apparatus for lifting the safety-valves from within a boiler : it consists of levers con¬ nected to the valve and to a screw worked by a handle outside the boiler. Lifts, in navigation, the ropes at the yard-arms, used to make the yards hang higher or lower, as required. Light. The meteorological pheno¬ mena induced by the action of light are, chiefly, atmospheric refraction, i. e. the temperature of the different strata of the atmosphere ; the tints which at certain times spread over the disc of the sun, the moon, and the stars; the various aspects of the waters of the ocean, of seas, and of lakes; the Fata Morgana; the mirage, and all those varied optical appearances which both celestial and terrestrial objects pre¬ sent when seen through atmosphe¬ ric strata of different degrees of elasticity. Light red is an ochre of a russet- orange hue ; principally valued for its tints. The common light red is brown ochre burnt; but the prin¬ cipal yellow ochres afford this colour best; and the brighter and better the yellow from which this pigment is prepared, the brighter will this red be, and the better flesh tints will it afford with white.' 265 LIMESTONE. LIG Lignum vita, or Guaiacum, is a very hard and heavy wood, shipped from Cuba and other adjacent islands. When first cut, it is soft and easily worked ; but it speedily becomes much harder on exposure to the air. It is cross-grained, covered with a smooth yellow sap, like box, almost as hard as the wood, which is of a dull brownish-green, and contains a large quantity of the gum guaiacum, w’hich is extracted for the purposes of medicine. The wood is used in machinery, and for rollers, presses, mills, pestles and mortars, sheaves for ships’ blocks, skittle-balls, etc. Limber-boards, short pieces of plank fitted from the limber-strake to the keelson of a ship, butting at the sides of all the bulk-heads, that they may be easily taken up. Limber-strake, the strake of wood waleing nearest the keelson, from the upper side of which the depth in the hold of a vessel is measured. Lime, or Quicklime. When required perfectly pure, lime is obtained by heating to whiteness, in an open platinum crucible, precipitated car¬ bonate : most marbles yield it mo¬ derately pure ; but as prepared for ordinary purposes, by the calcina¬ tion of common limestone in a fur¬ nace with coal, it is far otherwise. Limestone becomes lime on being de¬ prived of its carbonic acid and of the water it contains, whether hy- grometrically or in combination. The agent employed to effect this is heat. With the same heat, the calci¬ nation is effected with more ease and rapidity, in proportion as the stone is of a less compact texture than the smallness in bulk of the fragments into which it is reduced, or to its being impregnated with a certain degree of humidity. The contact of the air is not in¬ dispensable, but it exercises a useful -influence, especially in regard to argillaceous limestone. Moreover, no limestone can be converted into LIM lime in a vessel so close as to ren¬ der the escape of the carbonic acid impossible. Limestone which is pure, or nearly so, supports a white heat without inconvenience. Under the intense heat of the hydro-oxygen blow-pipe,this substance affords the brilliant light, the beautiful appli¬ cation of which to the microscope is now so well known. The com¬ pound limestone, on the other hand, alloyed in the proportions necessary to form hydraulic or eminently hydraulic lime, fuses easily. Its calcination demands certain pre¬ cautions : the heat ought never to be pushed beyond the common red heat, the intensity being made up for by its duration. The compound limestone, when too much burnt, is heavy, compact, dark-coloured, covered with a kind of enamel, especially about the an¬ gular parts ; it slakes with great difficulty, and gives a lime carbon¬ ized and without energy : some¬ times it will not slake at all, but becomes reduced, after some days’ exposure to the air, to a harsh powder altogether inert. The pure and compound lime¬ stones, when insufficiently burnt, either refuse to slake, or slake only partially, leaving a solid kernel, a kind of sub-carbonate with excess of base. The calcining of calcareous mi¬ nerals constitutes the art of the lime-burner. According to situa¬ tion, either fire-wood, fagots, brush¬ wood, turf, or coal is used. Lime-kilns of various kinds have been suggested and tried. The forms of interior most generally adopted are, 1st, the upright rect¬ angular prism ; 2nd, the cylin¬ der ; 3rd, the cylinder surmounted by an erect cone slightly trun¬ cated; 4th, a truncated inverted cone; 5th, an ellipsoid of revolu¬ tion variously curvated, or an egg- shaped kiln. The rectangular kilns are in use 266 LIMESTONE. LIM in Nivernais, and in the south of France, in which are burnt, at the same time, limestone and bricks. The limestone occupies very nearly the lower half of the capacity. The upper is filled with bricks, or tiles, laid and packed edgewise. The cylindric kilns are princi¬ pally employed upon works which consume a large quantity of lime in a short time. They are termed 4 field-kilns their construction is expeditious and economical, but precarious. Above a pointed oven¬ shaped vault, is raised, in the form of a tower, a high stack of lime¬ stone, which is enclosed by a cur¬ tain of rammed earth, and sup¬ ported outwardly by a coarse wat¬ tling, in which care is taken to leave an opening to introduce the fire beneath the vault. The kilns of the third kind are constructed in a solid and durable manner, like the four-sided kilns: no bricks are burnt in these; the largest stones occupy the lower part of the cylinder; the smaller pieces and fragments are thrown into the cone which surmounts it. The kilns of the fourth and fifth kind are specially intended for the burning with coal. The interior wall of the kiln is generally built with bricks, or other material unalterable by heat, ce¬ mented throughout a thickness of from 12 to 15 inches with a mix¬ ture of sand and refractory clay, beaten together. In the flare-kilns fed by logs or brushwood, the charge always rests upon one or two vaults built up dry with the materials of the charge itself. Underneath these vaults a small fire is lighted, which is gradually increased as they retire, in proportion as the draught esta¬ blishes itself and gains force. On reaching the exterior, the aperture at the eye of the kiln is suitably adjusted, and then kept constantly filled with the combustible. The air which rushes in carries the flame LIM to a distance over every point of the vaults: it insinuates itself by the joints, and is not long in extending the incandescence by degrees to the highest parts. There are some kinds of stone which the fire, however well re¬ gulated, seizes suddenly, and causes to fly with detonation : they can¬ not, without the risk of spoiling the charge, be used for the con¬ struction of the vaults and piers in loading the kiln. In such a case, materials which are free from this inconvenience are employed. Practice can alone indicate the time proper for the calcination. It varies with a multitude of circum¬ stances, such as the more or less green, more or less dry quality of the wood; the direction of the wind, if it favour the draught, or otherwise, etc. The master-burners usually judge by the general settling of the charge, which varies from i to In a kiln of the capacity of from 211'8 to 264'75, cubic feet, the fire lasts from 100 to 150 hours. In the coal-kilns by slow heat, the stone and coal are mixed. Of all the methods of burning lime, this is certainly the most precarious and difficult, more especially when applied to the argillaceous lime¬ stone. A mere change in the du¬ ration or intensity of the wind, any dilapidation of the interior wall of the kiln, a too great inequality in the size of the fragments, are so many causes which may retard or acceleratethe draught, and occasion irregular movements in the descent of the materials, which become locked together, form a vault, and precipitate at one time the coal, and another the stone, upon the same point: hence an excess or deficiency in the calcination. Sometimes a kiln works perfectly well for many weeks, and then all at once gets out of order without any visible cause. A mere change in the quality of the coal is suf- 2G7 m 2* I--—---—--- LIM LIME. LIM ficient to lead the most experienced lime-burner into error. In a word, the calcination by means of coal, and the slow heat, is an affair of cautious investigation and practice. The capacity of a furnace con¬ tributes, no less than does its form, to an equable and proper calcina¬ tion. There are limits beyond which they cannot be enlarged without serious evils. The bulk of coal burnt to pro¬ duce a cubic foot of lime neces¬ sarily varies with the hardness of the limestone used, hut within narrow limits. The calcination of limestones presents other important problems, which can only be solved by expe¬ riment. I Limes, hydraulic (artificial). Already the artificial limes have been ap- I plied to a number of important works. In the canals of St. Martin j and St. Maur they have almost ex¬ clusively been used, and nearly a thousand cubic metres have been employed within five years at the harbour of Toulon. These limes i have served for the fabrication of the mortar for the foundations of i several bridges, and their con¬ sumption is increasing daily in j Paris and its environs. The artificial hydraulic limes are prepared by two methods; the most perfect, but also the most expensive, consists in mixing with rich lime, slaked in any w r ay, a certain proportion of clay, and cal¬ cining the mixture: this is termed ‘ artificial lime twice Jcilned.' By the second process, any very soft calcareous substance is sub¬ stituted for the lime (such, for ex¬ ample, as chalk, or the tufas), which it is easy to bruise and re¬ duce to a paste with water. From this a great saving is derived, but at the same time an artificial lime perhaps of not quite so excellent a quality as by the first process,in con¬ sequence of the rather less perfect amalgamation of the mixture. In 268 fact, it is impossible, by mere me¬ chanical agency, to reduce calcare¬ ous substances to the same degree of fineness as slaked lime. Never¬ theless, this second process is the more generally followed, and the results to which it leads become more and more satisfactory. By a proper regulation of the proportions, a degree of energy may be given to the factitious lime, which will render it equal, if not superior, to the natural hydraulic limes. It is usual to take tw'entv parts of dry clay to eighty parts of very rich lime, or to one hundred and forty of carbonate of lime. But if the lime or its carbonate should already be at all mixed in the na¬ tural state, then fifteen parts of clay will be sufficient. Moreover, it is proper to determine the pro¬ portions for every locality. In fact, all clays do not resemble one another to such an extent as to admit of their being considered as identical: the finest and softest are the best. There is at Meudon, near Paris, a manufactory of artificial lime, set on foot by Messrs. Brian and St. Leger. The materials made use of are, the chalk of the country and the clay of Vaugirard, which is previously broken up into lumps of a moderate size. A millstone set up edgewise, and a strong wheel with spokes and felloes, firmly at¬ tached to a set of harrows and rakes, are set in movefnent by a two- horse gin, in a circular basin of about six feet and a half radius. In the middle of the basin is a pillar of masonry, on which turns the vertical arbor to which the whole system is fixed: into this basin, to which water is conveyed by means of a cock, four measures of chalk are successively thrown, and one measure of clay. After an hour and a half’s working, about fifty-three cubic feet (English) of a thin pulp is obtained, which is ir.ni LINK-MOTION. LTN drawn off by means of a conduit, pierced horizontally on a level with the bottom of the basin. The fluid descends by its own weight; first into one excavation, then into a second, then a third, and so on to a fourth or fifth. These excavations communicate with one another at top. When the first is full, the fresh liquid, as it arrives, as well as the super¬ natant fluids, flow over into the second excavation; from the second into the third, and so on to the last, the clear water from which drains off into a cesspool. Other excavations, cut in steps like the preceding, serve to receive the fresh products of the work, whilst the material in the first series ac¬ quires the consistency necessary for moulding. The smaller the depth of the pans in relation to their superficies, the sooner is the above-mentioned consistency ob¬ tained. The mass is now subdivided into solids of a regular form by means of a mould. This operation is executed with rapidity. A moulder, working by the piece, makes on an average five thousand prisms a day, which will measure 211‘8 cubic feet. These prisms are arranged on drying-shelves, where in a short time they acquire the degree of desiccation and hardness proper for calcination. At Paris a mixture of coke and coal is employed; and the common mode of burning by slow heat rendered necessary by that kind of combustible. The artificial hydraulic limes are intended to supply the place of the natural ones in those countries where the argillaceous limestone is entirely wanting, and which are commonly sold in Paris. Lime-tree (the) is common in Europe, attains considerable size, is very light-coloured, fine and close in the grain, and is used in the con¬ struction of piano-fortes, harps, etc.: it is particularly suitable for carving, from its even texture and freedom from knots. The works of Gibbons at Windsor Castle, and St. Paul’s, London, are of the lime- tree. Limning , a term formerly applied to portrait-painting, is drawing or painting the body and limbs of the human figure. Linch-pin, the small pin, in’carts, etc., that is put at the ends of the axle- tree to confine the wheels on them steadily. Linear perspective is that which de¬ scribes or represents the position, magnitude, form, etc., of the se¬ veral lines or contours of objects, and expresses their diminution, in proportion to their distance from the eye. Link-motion , a new apparatus for re¬ versing steam-engines : it is used in locomotive engines instead of the reversing forks, and consists of a link with a slot from end to end, into which a guide-block fits, and is connected to the slide-valve rod : the rods of the two eccentrics are connected one to each end of the link, which is raised or lowered, or held in a central position, by appa¬ ratus attached to the centre of it, moved by the reversing lever. When the link is in a central po¬ sition with regard to the slide- valve rod, the guide-block remains stationary, as it is then at the centre upon which the link vibrates. When the link is up, the guide-block is at the lower end, and the slide receives motion from the backward eccen¬ tric. When the link is down, it receives motion from the forward eccentric. See plate 8, elaborately drawn and explained in Yol. 79*, in ‘ Rudimentary Series.’ Links, in locomotive engines, are flat or round pieces of iron with round holes at each end: they are used \ to connect together, by bolts, dif¬ ferent parts of the mechanism of , the engine. Linseed oil has the fullest body and dries better than any of the three | 2J9 LIN LOCKS. LOC oils (linseed, nut, and poppy) in use with artists; its colour is a strong yellow, but this effect does not arise from the action of the fire in extracting the oil, but from the pellicle which covers the grains, and which contains a strong co¬ louring matter soluble in oil. Lin¬ seed oil, cold drawn, is equally coloured with the other sorts, hut, like that of wax, this colour is carried off by exposure to the sun. Lintel, a piece of timber or stone placed horizontally over a door¬ way or window, to support the superincumbent weight. Lintel. “ And ye shall take a bunch of hyssop, and dip it in the blood that is in the basin, and strike the lintel and the two side-posts with the blood that is in the basin; and none of you shall go out at the door of his house until the morn¬ ing.”— Exodus-x. ii. 22. Liquid rubiate, or Liquid madder lake, is a concentrated tincture of mad¬ der, of the most beautiful and per¬ fect rose-colour and transparency. It is used as water-colour only in its simple state, diluted with pure water, with or without gum; it dries in oil, by acting as a dryer to it. Mixed or ground with all other madder colours, with or with¬ out gum, it forms combinations which work freely in simple water, and produce the most heautiful and permanent effects. Lithography, the art of drawing and engraving on^stone, and taking im¬ pressions from the same at press, similarly to copper-plate printing, but differing in manipulation. Little winds, in mining, an under¬ ground shaft, sunk from the hori¬ zontal drift, by which the top of the winds communicates with the side or bottom of the great work¬ ing-shaft. Lloyd's Register. Lloyd’s rules for British and foreign shipping exert a most essential and powerful in¬ fluence on the construction and science in the building of shipping of this country as well as those of continental and transatlantic mari¬ time nations. Insurances from loss can only be made at Lloyd’s by conforming to the rules laid down by competent surveyors. See Vol. 54* in the ‘ Rudimentary Series.’ Load water-line, the mark on a ship which the water makes when she is loaded. Loam, a natural mixture of sand and clay: in the neighbourhood of London, loam consists of fine red¬ dish-grey sand 87 parts, alumina 13 parts = 100. Local colours are such as faithfully imitate those of a particular object, or such as are natural and proper for each particular object in a pic¬ ture ; and colour is distinguished by the term trial, because the place it fills requires that particular co¬ lour, in order to give a greater character of truth to the several colours around it. Lock, a mechanical contrivance to fasten a door, gate, or any place or thing for security. A vast deal of ingenuity has been exercised to prevent false openings : keys of va¬ rious kinds are made to fit the wards (interior contrivances), and prevent what is called picking, the key being made only to suit that belonging to the possessor. Lock, in inland navigation, a portion of a canal confined between a sluice¬ gate and a flood-gate, to facilitate the passage of boats in ascending or descending planes. Lockrand, a course of bond stones, or a bonding course, in masonry. Locks for canal and river navigation. The earliest approximation to what is now known by the name of lock, consisted of a simple dam formed across the bed of a river, so as to raise the water to such a height as to allow vessels to float along it. Where the river had a considerable fall with a strong current, it was necessary to have these dams at short distances from each other, otherwise the requisite depth of 270 LOCKS. LOC water could not be obtained. As the whole space between two of these dams was in fact the lock, it was necessary, in passing from one level to another, to run down the water for the whole of that distance, thereby causing consider¬ able delay, and a waste of water that would now he considered a serious evil. In China these dams are common, and they have also been used on the Continent. See Vol.121 oftlie ‘Rudimentary Series.’ Locks with a double set of gates , hut no chamber-walls, are now of ordi¬ nary construction. The evils at¬ tendant on the dams formerly constructed were in a great mea¬ sure removed by the introduction of double sets of gates or sluices, the upper set being constructed so near to the lower as only to leave room enough for the vessel or ves¬ sels to float between them. Framed gates were also used instead of se¬ parate beams and planks, because the space to be emptied or filled was so small that a very short time was required to pass the water, and there was no stream of suffi¬ cient strength to prevent their being easily opened. Where these locks are intended for rivers, it is usual to make a side cut or arti¬ ficial canal for the purposes of the navigation, and to leave the river- course for the passage of the sur¬ plus water. A quick bend of the river is generally chosen for one of these cuts; and to keep the water in the upper part of the river to a sufficient height for navigation, a dam or weir is made across the old river-course at or below the point where the artificial cut quits it. The lock is then built at the most convenient part of the cut, and its fall made equal to the difference in the levels of the water at the top and at the bottom of the dam or weir. When a vessel is going up the river, she floats along the cut, and passes between the lower gates into the lock; the lower gates are LOC then closed, and the valves or paddles of the upper gates being opened, the water flow's into the lock, and rises to the level of the upper part of the river; the upper gates are then opened, and the vessel floats out of the lock. The reverse of this operation conducts a vessel down the river. The abutments for the gates have been made of timber, brickwork, and masonry; but when the double set of gates was first introduced, it was usual to leave the space be¬ tween the upper and lower gates tmprotected by either timber or any kind of building. Of course the agitation of the water in the lock was constantly washing away the earthen banks, thereby causing a risk of their being broken down by such continued weakening ; and by enlarging the space between the two sets of gates, it occasioned a loss of time in emptying and filling, as well as a waste of water. Lock (common modern canal). —The difference of altitude between the upper and lower levels, where the locks are constructed, varies ac¬ cording to local circumstances. Where the ground is longitudinally steep and water plentiful, the locks are generally made of greater lift or fall than where the ground is comparatively flat and water scarce. It is evident, that where the super¬ ficial area of locks is the same, one having a rise of 12 feet would re¬ quire twice the quantity of water to fill it that would be requisite for one of 6 feet. Having many locks, however, of small lifts, instead of a few of greater, increases the ex¬ pense, as well as the time for pass¬ ing them. For narrow canals these locks are generally made about 80 feet long, and to 8 feet wide in the chamber. On the Caledonian canal they are 180 feet long, 40 feet wide, and 30 feet deep. Locks are also made of every intermediate size. Lock-gates have till lately been 271 LOC LOCKS. LOC made of timber; but in consequence of the difficulty of procuring it of sufficient size for those on the Caledonian canal, cast - iron was partially adopted for the heads, heels, and ribs. Iron gates, cast in one piece, have been used on the Ellesmere canal, as well as others with cast-iron framing and timber planking. Locks with side ponds. —When water is scarce, it is common to construct side ponds, by which a considerable portion (in general one - half) is saved. The usual number of these ponds is two; for it has been de¬ termined by experience, that when a greater number has been made use of, the loss occasioned by leak¬ age and evaporation has sometimes been more than equal to the ad¬ ditional quantity of water thus re¬ tained. Locks for the transit of vessels of different sizes. —Where vessels of different sizes have to pass the same locks, three pairs of gates are sometimes placed instead of two, —the distance between the upper and lower pairs being sufficient to admit the largest vessels, and that between the upper and middle pairs being adapted to the smaller class. By this contrivance, wdien a small vessel is to be passed through, the lowest pair of gates is not used; and when a large vessel goes through, the middle pair of gates is not worked. Thus it is evident that the quantity of water contained between the middle and lower pair of gates is saved when a small ves¬ sel passes, compared with what would be required wmre the middle set of gates omitted. Locks (parallel double-transit ').— Where the transit is great, much time and water may be saved by a double-transit lock, which is two locks placed close to and parallel with each other, with a communi¬ cation between them, which can be opened or cut off at pleasure by valves or paddles. As one of these locks is kept full and the other empty, a vessel in descending floats into the full one: the upper gates are then closed, and the water is run, by means of the connecting culvert, into the empty lock (the gates of which were previously closed), till the water in the two locks is on the same level, which will be when each is half-full: the connecting paddles are then closed, and the remaining half of the water in the descending lock is run into the lower canal. The next descending vessel has to be floated into the lock which remains half-filled, and which consequently requires only half a lock of water to be run from the upper pond to raise it to the proper level, and then that half is transferred to the lock previously used, to serve the next descending vessel; but supposing a vessel to be ascending arter the first descent, it will enter the empty lock, and receive a quarter-lock of water from that which remained half-filled: of course, three-quarters of a lock of water is now required from the upper canal to complete the filling. If a descending vessel next follows, it enters the full lock, and its water is run into the lock which was previously left a quarter-full; and wdien both have arrived at the same level, it is evident they will be each five-eighths full, and the succeeding descending vessel will require only three-eighths of a lock of water from the upper pond or canal. From these observations, it will be seen that the double-transit lock saves nearly one-half of the w r ater which a common single lock would require. Sometimes the two parallel locks are made of different sizes, to suit the various descriptions of vessels that may have to pass. Locks connected longitudinally, com¬ monly called a Chain of Locks .— When loss of water is of no conse¬ quence, a considerable expense is 272 LOC LOCOMOTIVE ENGINES. LOG sometimes saved by placing the locks close together, without any intermediate pond ; for by passing from one immediately into the other, there is only required one pair of gates more than the number of locks so connected, besides a proportionate saving of masonry. Thus eight connected locks would only require nine pairs of gates; whilst if they were detached, they would require sixteen pairs. But to show that these cannot be adopt¬ ed with propriety excepting where water is abundant, it is necessary to observe, that every two alternate | ascending and descending vessels will require as many lockfuls of water as there are locks: for in¬ stance, if a vessel has just ascended, it has left all the locks full; a de¬ scending vessel then enters the upper lock, and when its gates are closed,the water is run down: but all the locks below being previously tilled, they cannot contain it, and it consequently passes over the gates or weirs of all of them into the lower canal: the vessel has by this means descended to the level of the second lock, the water in which must also be run into the lower canal, for the same reason as al¬ ready stated. When the water of j all the locks has thus been run down, an ascending vessel will re- j quire all these locks to be filled j from the upper canal, which, how¬ ever, will be retained in the locks ready for the succeeding vessel to pass down. From this it will be ; evident, that where eight locks are connected, a descending vessel ■ draws no water from the upper canal, because the locks are pre¬ viously all filled, but it empties eight locks of water into the lower canal: an ascending vessel, on the contrary, empties no water into the lower canal, because all the locks were previously emptied, but it draws eight lockfuls from the upper canal, in order to fill them : consequently, the passing of one ascending vessel, and one descend¬ ing, requires the expenditure of eight lockfuls of water. Other modes of passing vessels from one level to another, by sub¬ stituting machinery, either wholly or in part, have been adopted ; but 1 these have either failed entirely, or have not been brought into general use. Locomotive Steam-engines , a class of | travelling machines adapted either for railways or common roads, were originally designed for the latter, but did not succeed; and roads were then made for them, called railways, on which they have been most successful. The principle of action being the same in both kinds, a description of the railway variety will explain the manner in which progressive motion is obtain¬ ed by the agency of steam. Locomotion or progression is the combined effect of a number of parts in each engine performing separate duties. The principal of j these parts and the plan of their co-operation may be thus classed: i 1st. The parts which generate the ! steam. 2nd. The parts which regulate the employment of the steam. 3rd. The parts by which the driver i controls the action of'the engine. j 4th. The parts immediately con¬ cerned in producing locomotion. 5th. The parts which excite the rapid combustion of the fuel. 6th. The parts which supply water to the boiler. 7th. The parts which support the engine on the rails. 8th. The manner in which loco¬ motion is produced by these parts. In explaining them and their effect as thus arranged, we have 1st. The parts which generate the steam, called the boiler, con¬ taining internally a fire-box, varying according to the dimensions of the engine from 25 (as in the ‘ Rocket’) to 303 small tubes (as in the broad- gauge engines), a regulator, and 273 m 3* LOC LOCOMOTIVE ENGINES. LOC a steam-pipe. Externally, a chim¬ ney and two safety-valves are fixed to the boiler. 2ndly, The parts which regulate the employment of the steam are, two slide-valves (covering the passages to and from the cylinders), attached to two sets of ‘valve-gear,’ worked by two eccentrics for the ‘ forward’ and two other eccentrics for the ‘ backward’ motion of the engine; but only two of them work at one time, the other two being what is called ‘ out of gear.’ Four rods called eccentric-rods, encircling the eccentric-sheaves at one end, and jointed to the slide-valve gear at the other end, complete the con¬ nection of the slide-valves to the eccentrics fixed on the axle of the driving-wheels. 3rdly, The parts by which the driver controls the action of the engine are, three sets of levers and rods connected to the slide-valve, eccentric-rods, regulator-valves, and feed-pipe cocks, whereby he can ‘ put on’ or ‘shut off’ steam to the cylinders, water to the boiler, or place the slide-valves in a ‘for¬ ward ’ or ‘ backward ’ position at his pleasure. These arrangements are usually called the ‘ hand-gear.’ 4thly,The parts immediately con¬ cerned in producing locomotion are, two cylinders, on which work two steam-tight pistons, fixed on the end of the piston-rods. On the open end of the piston-rods are also fixed T-pieces, called cross¬ heads, which slide between or round guide-bars, called motion- bars, fixed parallel with the cylin¬ ders. By this means the pistons can only move in a right line with the cylinders. Two strong rods, called connecting-rods, attach the cross-heads to the driving-wheels, or to a cranked axle when there is one used. Whether the pistons are connected to a cranked axle or to the arms of the driving-wheels, this connection is always made at an angle of 45 degrees to each other; therefore the one piston is in the centre of the cylinder exert¬ ing its greatest power during that part of the stroke when the other piston is at the end of the cylinder exerting no powrnr. (This excel¬ lent arrangement was amongst the first improvements introduced by the late Mr. G. Stephenson, in 1814, who thus placed the locomo¬ tive in the same high position, as to efficiency, as was previously done for fixed engines by Watt.) The connection being thus completed between the pistons and the driv¬ ing-wheels, it is evident that any movement of the one must imme¬ diately act upon the other. 5thly, The parts which excite the rapid combustion of the fuel re¬ quired in locomotive engines are, the chimney and a pipe called the blast-pipe, so made as to cover the exhausting passages from both cy¬ linders, and terminating in the centre of the chimney, near the level of the top of the boiler. It is the escape, through this pipe, of each succeeding cylinderful of steam, or that portion of it allowed to escape by the slide-valves, which causes the ‘ beats ’ or ‘ pulsations ’ so distinctly audible w'hen the locomotive is at work. 6thly, The parts which supply water to the boiler are, two force- pumps, connected by two feed¬ pumps to the boiler, and to a re¬ servoir of water. The pumps are worked either from the cross-head, or from eccentrics on the axle of the driving wheels. 7thly. The parts which support the engine are, 2, 4, or 6 wheels, besides the driving-wheels, a set of springs, and a strong frame on which the boiler and machinery are securely fixed. 8thly, The manner in which lo¬ comotion is produced from the co¬ operation of these several parts is as follows. The boiler is filled with water until it completely sur¬ rounds all the tubes and inside fire- 274 LOC LOCOMOTIVE ENGINES. LOC box. Fire is then applied, and in due time steam is generated from the water and collected between the surface of the water and the top of the boiler, until it has reached the pressure required. On the regulator being then opened, and the slide-valves placed in their working position by the driver, the steam passes from the boilerthrough the steam-pipe to the cylinders, where its force moves the pistons, which, being attached to the driv¬ ing-wheels (as has been explained), causes them to revolve, and thus produces locomotion. The slide- valves and pumps being wrought from some part set in motion by the piston, regulate the admission of steam to the cylinder, and of water to the boiler. When the steam has moved the piston to the end of the cylinder, a passage is opened for its escape to the atmo¬ sphere through the blast-pipe, and the velocity of this escaping steam creates a partial vacuum in the chimney, causing a rush or ‘ blast ’ of air through the fire to fill this vacuum; which blast excites the rapid combustion of the fuel, and consequent rapid generation of steam. This completes the duties of one admission of steam to the cylinders, until its escape to the atmosphere ; and when this escape has taken place, another admission of steam, to the opposite side of the piston, forces it back to the other end of the cylinder; and by the medium of the crank, the re¬ ciprocating motion of the piston is converted into a rotatory one, and the locomotion begun by the first admission of steam to the cylinders is continued by the second and succeeding admissions. The repetition of these simple operations has amazed and gratified the world, by safely conveying heavy passenger-trains at upwards of 70 miles an hour, and merchan¬ dise trains of 600 tons weight at 25 miles per hour !—the mere idea of which, not many years since, would have been regarded as purely fabulous. Such is the modern railway loco¬ motive,—an illustrative example of the genius of man ; but, like other important inventions, it is the joint production of many minds, and many more are still directed to its further improvement. The records of the Patent Office show, that from January, 1840, to the end of September, 1849, no less than 226 patents were enrolled, all of them more or less applicable to the steam-engine and its ap¬ pendages. Of these 226 patents, 45 were enrolled during the first nine months of 1849. It has been remarked that steam-engines and railways were too matter- of - fact subjects for poets and painters; but from the above record it is evident that they deeply impress them¬ selves upon the inventive intellect of the world; and if the prodigies performed by steam remain un¬ sung or unportrayed, they dare, if not realize, the very sublimity of both poetry and painting ; for what more interesting scene to delineate than one of these stately machines moving safely along, at eagle-speed, the very elite of the land (including even the Royal Family), through districts rich in the historical as¬ sociations of past ages, and still teeming with the works of nature and of art! Surely it cannot be that the subject is too lofty a one for poetical or pictorial illustration, for in greatness of idea lies the success of both. A brief review of the progress of locomotive engines is all that can be here given. It is now about 2000 years since the powers of steam were recorded by Hero of Alexandria, but it is only 200 years (in 1650) since it was first usefully employed by the Marquis of Wor¬ cester. The first idea of using it for propelling carriages is generally ascribed to Dr. Robison, in 1759, 275 LOCOMOTIVE ENGINES. LOC when it was suggested by him to Watt, who included a steam-carriage in hispatents of 1769 and 1784, but never carried them out. In 1786, Oliver Evans, of Philadelphia, had clear perceptions of the advantages of applying steam to waggons, | boats, and mills ; but the want of friends and means compelled him to confine his exertions to steam- j mills. From 1802 to 1805, Trevi¬ thick applied steam-carriages to both common roads and railways, with considerable success for first experiments; and his engine, with Stephenson’s improvements, is now i the modern locomotive. About the | year 1803, it appears that a Mr. Fredericks also made a steam-en¬ gine for a silver mine in Hanover, which, in 1811, was employed to convey their Majesties and suite of Westphalia over the mineral rail¬ way at considerable speed. This was probably the first royal trip on a railway. From 1805 up to 1814, invention was directed to ensure the adhesion of the wheels upon the rails ; and many ingenious plans were tried,some of which succeeded well at slow speeds, but were not calculated for high velocities. In 1814, however, Mr. Blackett, of the Wylam Railway, reverting to Trevithick’s plan, fully established the fact, that on a level, or mo¬ derately inclined railway, the ad¬ hesion of a smooth iron w’heel upon a smooth iron rail was sufficient to draw heavy loads. He tried both six and eight wheeled engines. In 1814, Mr. Stephenson introduced two cylinders, or two complete steam-engines, to one locomotive. From this time up to 1829, the powerful opposition of the owners of other modes of conveyance greatly retarded the progress of the locomotive engine; and so strong was the feeling that they were not economical, that both Mr. Walker and Mr. llastrick re¬ ported against them, in 1829. These reports, and one of a doubt¬ LOC ful character by Telford, led to the offer of a prize of £500, in 1829, by the directors of the Liverpool and Manchester Railway, for the best locomotive engine, whose weight was not to exceed six tons. This proceeding gave an important impulse to locomotives, and ended in establishing their superiority over all other existing systems of travelling. Five competitors ap¬ peared, namely, Messrs. Stephen¬ son, Erickson, Hoekworth, Burstal, and Brandreth. The machinery of the two last was not suitable, and did not proceed to trial. Mr. Stephenson’s ‘ Rocket,’ Mr. Erick¬ son’s ‘ Novelty,’ and Mr. Hock- worth’s ‘ Sanspareil,’ were all tried, and the prize was fairly won by the ‘ Rocket,’ which, after the trials W'ere over, reached a speed of 35 miles per hour, and the ‘ Novelty’ about 24 miles per hour. The ‘ Rocket ’ embraced the fire¬ box, tubes, and blast-pipe of the modern locomotive. The ‘ Novelty ’ embraced the plan now much used on short lines, of carrying engine, fuel, and water, all on one frame. The ‘ Sanspareil ’ embraced the blast-pipe of the modern engine, with the single returned tube of the older locomotives. From this it will be seen that this competition at once brought out the leading features which have since rendered the locomotive engine so popular throughout the world. From 1830,up to the introduction of the 7-feet gauge on the Great Western Railway, in 1838, no marked improvement took place in the locomotive, but the rivalry which sprang up between the gauges served greatly to develope their capabilities. Engines of a novel construction, having the boiler on one frame, and the machinery on another frame, were tried on the Great Western Railway ; also engines embracing Trevithick’s plan of working the 276 LOCOMOTIVE ENGINES. LOC driving-wheels by toothed wheels, fixed on a separate cranked axle, were tried, but all abandoned for engines modelled from one of Stephenson’s; and the last new Great Western engines only follow up his latest improvements and Gray’s expansive slide-valve motion on a large scale. A number of patents have been enrolled for improving the loco¬ motive engine, but a few only have been reduced to practice. Amongst the more conspicuous of them are, Mr. Stephenson’s im¬ provements in the slide-valve mo¬ tion ; Mr. Gray’s expansive mo¬ tion ; Mr. Crampton’s arrangement of wheels ; Mr. Bodmer’s arrange¬ ment of four pistons in two cylin¬ ders ; Mr. M'Connell’s tank engine; Mr. Samuel’s express engine; and Mr. Adam’s steam-carriage. The improvements in the mechanism of the slide-valve motion, by Messrs. Stephenson and Gray, have been widely adopted. Mr. Crampton has engines of his plan at work both in England and on the Con¬ tinent, which enable high driving- j wheels to be used on the narrow gauge, without raising the centre of gravity. (For popular descrip¬ tion and illustration, see Vols. 78* and 79* in ‘ Rudimentary Series.’) Mr. Bodmer’s plan is to admit the steam between two pistons in one cylinder acting on two cranks, so as to compensate the strain on the frame and machinery. His engines work steadily, and are in¬ genious in construction. The tank engine carries on the same frame water and fuel, its tank for water being placed on the top of the boiler. This is the plan adopted on the Great Western Rail¬ way ; but on narrow-gauge lines the tank is usually placed below the boiler and framing,—-a better arrangement, where the machinery permits it to be done. Mr. Samuel’s express engine weighed only 25 cwt., and con- LOC vexed seven passengers at the rate of 30 miles per hour on the Eastern Counties Railway. Mr. Adam’s steam-carriage is on this plan, with a very handsome carriage for passengers, all on one frame, and has been tried on some of the branch railways of both gauges. Having thus briefly glanced at the progress of the locomotive en¬ gine, it only remains as briefly to notice some important discussions which have agitated the mechani¬ cal world regarding them. From the earliest introduction of locomotives, four, six, or eight wheels appear to have been used, according to the designs of the ma¬ kers ; but about 1840-1-2, an ani¬ mated discussion of the respective merits of the four and six wheeled engines was carried on in the co¬ lumns of the railway press. Both classes have their merits, and both classes had able advocates, but pub¬ lic opinion evidently tended in fa¬ vour of the six-wheeled engine as the safer of the two under all con¬ tingencies : hence the greater pro¬ portion of the present locomotives i have six wheels. The gauge controversy of 1845- 6-7-8 led to the re-introduction of eight - wheeled engines on both gauges, weighing about 36 tons each, which realized speeds of about sixty and seventy miles per hour. The weight of these monster en¬ gines, it will be observed, is more than eight times that of the ‘ Rocket’ (4^ tons), which won the prize in 1829, whilst the speed is only twice that of the ‘Rocket’ (thirty-five miles) at that time. It is worthy of remark, that in 1829 the exist¬ ing engines of 10 to 16J tons were considered as far too heavy, and the Liverpool and Manchester directors bound competitors not to exceed six tons weight. In 1849, the same feel¬ ing prevailed, and the injury done to the railway by these 36-ton en¬ gines is much complained of, and 265 * LOC . LOCOMOTIVE ENGINES. LOG tank engines and steam-carriages embody this feeling in practice. A description of the locomotive can scarcely be closed without no¬ ticing the death of its great im¬ prover, Mr. G. Stephenson, who died in 1848, aged 68 years. He found the locomotive a very imperfect machine ; he left it in that efficient state that even the daring genius of a Brunei could only copy his plans for the 7-feetgauge. This is another testimony to that far- seeing intellect which so early grasped the principal requisites for an efficient locomotive, and whose genius coped with and overcame the leading engineers of England, in 1829, by establishing both loco¬ motives and the Liverpool and Manchester Railway against all op¬ position, and from which sprang that system of railways which has added so immensely to theresources of the nation—ay, of the world. Civil services, military services, naval services, and no services, have at all times been liberally rewarded by the Crown and Legislature; but there are no such rewards, no order or merit for such men as the Stephensons, Watt, Arkwright, Field, the Rennies, Whitworth, etc., who are the mainstays of our progress, our greatness, and our power. This is wrong—very wrong, and ought to be amended. How¬ ever, if the Crown forget, and the Legislature neglect such men, it is consolatory to know, that their names will be embalmed in the hearts of the people, whilst the profligacy of honours and rewards to those having no real claim on the gratitude of the nation is uni¬ sally condemned. Upon the Taunus Railway, an apparatus is in use, which, from its simplicity and efficiency, cannot easily be excelled. It is attached to the hinder part of the tender, and is used in case of emergency, as well as being constantly used when at the stations, where it is necessary to uncouple the engine and tender from the train, thereby saving great trouble, and with less danger to engine-men and fire-men, as they can disconnect at any speed or at any time, whether the engine and train are in motion or not. (For a better elucidation of this simple and ingenious contrivance, see the work on the ‘ Taunus Railway,’4to.) Locker , a small closet or cupboard : lockers were used in churches to hold sacred relics. Locust-tree (the) of North America is of a greenish yellow; is tough and durable, and used for trenails for ships, for posts, stakes, paling, etc. Lode, in mining, a vein of ore. Loft, a room in the roof of a build¬ ing ; a store-room in a theatre ; a depository for hay and corn in a stable : a music-loft; a singing-loft; a rood-loft in a church. Lofty tin, rich, massive, and rough tin. Log, in navigation, a small triangular piece of board balanced by a thin plate of lead so as to swim perpen¬ dicularly, and, being fixed to a line, measures the ship’s way. Logarithms are the artificial numbers used to facilitate or abridge arith¬ metical calculations, and may be considered as expressing the rela¬ tion between an arithmetical and geometrical series of terms, or between ratios and the measures of ratios, and are the indices or expo¬ nents of a series of numbers in geo¬ metrical progression. The origin and nature of logarithms may be easily explained. In arithmetical series the quan¬ tities increase or decrease by the same difference, but in a geome¬ trical series they increase or dimi¬ nish by a common measure. The first of the following lines exhibits an arithmetical progression ; all the other lines are examples of geome¬ trical progression. 1— 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. 2— 1, 2, 4, 8, 16, 32, 64,128, 256, 512. 266* LOMBARDIC SCHOOL. LOG 3— 1, 3, 9, 27, 81, 243, 729, 2187, 6561,25683. 4— 1, 10, 100, 1000, 10,000, etc. Here consider the upper line as the index to all the rest; every terra of it is the logarithm of a corresponding term in each of them ; and it is evident that an infinitude of other lines, or any one of the same lines, varying the point of commencement, and containing numbers in geometrical progres¬ sion, might be added, to all of which the same arithmetical series might furnish logarithms. M. Thoman, an ingenious French mathemati¬ cian employed by the Co. Credit Mobilier of Paris, has compiled a series of logarithmic tables to cal¬ culate the values and interests of moneys at every and ^ per cent. Logeum, the pulpitum or wooden stage of a theatre, placed upon the proscenium or permanent stage. In the Greek theatre the pulpitum extended into the orchestra beyond the proscenium. Logium, a hovel or outhouse. Logwood, from Campeachy, Jamaica, Honduras, etc., is largely used as a purple or dark-red dye-wood. Lomazzo (Gio. Paolo) of Milan, pupil of Cerva of Milan ; he published his treatise on painting in 1584, and which he condensed in his idea of the ‘ Temple of Painting,’ printed in 1590. LombardicArchitecture, a style which immediately succeeded the decline of the Roman style. Lombardic School of Painting. The distinguishingcharacteristics of this school are, grace, an agreeable taste for design, without great correct¬ ness, a mellowness of pencil, and a beautiful mixture of colours. An¬ tonio Allegri, called Correggio, was the father and the greatest orna¬ ment of this school: he began by imitating nature alone, but as he was chiefly delighted with the graceful, he was careful to purify his design; he made his figures elegant and large, and varied his LOR outlines by frequent undulations, but was not always pure and cor¬ rect, though bold in his concep¬ tions. Correggio painted in oil, a kind of painting susceptible of the greatest delicacy and sweetness; and as his character led him to cultivate the agreeable, he gave a pleasing, captivating tone to all his pictures. London and Nottingham whites. The best of these do not differ in any essential particulars materially, nor from the white leads of other ma¬ nufactories. The latter, being pre¬ pared from flake-white, is gene¬ rally the greyest of the two. The inferior white leads are adulterated with whiting or other substances, which injure them in body and brightness, dispose them to dry more slowly, to keep their place less firmly, and to discolour the oil with which they are applied. All the above are carbonates of lead, and liable to froth or bubble when used with aqueous, spiritous, or acid preparations. Longitude, length; the distance of any part of the earth, east or west, from London, or any other given place. Long timbers, in ship-building, those timbers in the cant bodies which reach from the dead-wood to the second futtock-head. Loobs, tin slime or sludge. Loof in navigation, pronounced luff, a term applied when a ship going large before the wind, is brought close by the wind ; to put the helm towards the lee-side. Loop, a part of a block of cast-iron, broken or melted off from the rest. Loop, a rail of bars joined together like a gate, to be removed in and out at pleasure. Loop, a hinge of a door. Loop-hole, a narrow opening or cre¬ nelle used in the battlements of the castles of the early English. Lord of the land or tree, in Cornwall, the person in whose land the mine is; therefore the part which he re- 267* LOR MACHINERY. MAG serves to himself for liberty to work a mine in his land is the one-sixth, one-seventh, one-eighth, or any other proportion, free of expense, and called the ‘ dues’ dish.’ Lorication, the filling of walls with mortar. Louvre, a lantern; a turret on the roof of an ancient hall or kitchen for the escape of smoke and for ventilation, now made an orna¬ mental and pleasing object. Low-pressure engine. (See Steam- engine.) Low-pressure steam- engine is when the steam-engine is worked at a low pressure of steam, when the steam is drawn oflf into a condenser apparatus. Loxodromics, art of oblique sailing by the rhomb, which always makes equal angles with every meridian. Lozenge, in geometry called a rhomb, and when the sides are unequal, a rhomboid ; in heraldry, a four-cor¬ nered figure, resembling a pane of glass in old casements. Lozenge moulding, a name given to the Norman style of mouldings and ornaments, which are shaped like lozenges. Lubricate, to make smooth or slippery. Lubricator, an oil-cup or other con¬ trivance for supplying oil or grease to rubbing surfaces, in order to diminish friction. Lucerna, an oil-lamp. The Greeks and Romans originally used can¬ dles ; but in later times these were chiefly confined to the houses of the lower classes. Lugsail, in navigation, a small sail hoisted occasionally on the mast of a boat or small vessel. Lychnus, a lamp suspended, or a pen¬ dent light. Lysis, some member above the corona of a podium, introduced in temples, and in the scene of a theatre. M. j Machine Organa, defined by Vi- i truvius, in his 10th book, as con¬ trivances for the concentration and application of force, which are known by the names of instru- ! ments, mechanical powers, ma- 1 chines, engines, etc. Machinery, a general term applied to \ mechanical combinations of parts for creating power, or producing works which may otherwise be, more or less perfectly, made with the hands. The first class of these combinations is usually distin¬ guished by the name of engines; the second, by that of machines. Engines, or machines for crea¬ ting or accumulating and applying power, are distinguished from each other according to the material employed in the creation of their power, as air-engines, water-en¬ gines, gas-engines, steam-engines, electric engines, etc. Machines employed in the ma¬ nufacturing arts are named accord¬ ing to their products, as lace-ma¬ chinery, rope-machinery, paper-ma¬ chines ; or to the processes they perform, as spinning-machinery, printing-machinery, sawing-ma¬ chinery, etc. The materials of which machine¬ ry is composed are, wood of various kinds, iron, brass, copper, and other metals, with flexible materials for bands, cords, etc., as wool, caoutchouc, and leather. The several parts of machinery are, frames, plummer-blocks, car¬ riages, bolts and nuts, pins, shafts, wheels, pinions, levers, cranks, springs, screws, pulleys, riggers, bands or belts, and cords, etc., studs, tappets, wedges, rods, cylin¬ ders, tubes, pistons, valves, buckets, floats,weights, beams, racks, chains, clutches, winches, etc. (See also Vols. 114 and 115, for popular elucidation, in the ‘ Rudimentary Series.’) The power of engines, as distin¬ guished from machines, depends upon the nature of the material 268* MAC MADDER. MAG from which their power is gathered. The mere mechanical effect of every piece of machinery is calculable upon its combinations of certain elementary forms, commonly term¬ ed the mechanical powers, with deductions from the effect of these for friction between the parts, for rigidity of parts which are theore¬ tically supposed to be perfectly flexible, and for the elasticity of parts which are supposed to be perfectly rigid. The mechanical powers, some¬ times described as six in number, viz. the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw, are reduci¬ ble to two only, viz. the lever and the inclined plane, in each of which the effect produced is just as many times greater than the power em¬ ployed, as the space through which the power moves is greater than the space through which the effect is continued. Thus, if with a lever a weight be raised ten times greater than the weight or power by which it is raised, this weight or power will have to move through ten times as much space as the height through which the greater weight is raised. Propriety of form in the detail of machinery depends upon two circumstances. The first is, that the parts subject to wear and tear, and influenced by strains, should be capable of motion or adjustment: the second, that every portion should be equally strong, and pre¬ sent to the eye a uniform figure, or one that is consistent with its degree of action: theory, practice, and taste, all must combine to produce such. A great extent of beauty is attainable in all the details, but mathematical reasons cannot be given why a certain arrangement of lines should be preferable to another, provided they are equally strong. Truth does not strike us without the as¬ sistance of custom ; but so great is the force of custom, that unassisted by truth it has worked the greatest miracles ; and it certainly must be this universal Mentor which gives us the pow'er to choose between forms. Macellum, a market-place for all kinds of provisions. Maceria, a rough wall. Machicolations, openings formed for the purpose of defence at the top of castles and fortifications, by set¬ ting the parapet out on corbels, so as to project beyond the face of the wall. Madder carmine, or Field's carmine, is, as its name expresses, prepared from madder. It differs from the rose lakes of madder principally in texture, and in the greater rich¬ ness, depth, and transparency of its colour, which is of various hues, from rose-colour to crimson. Madder orange, or Orange lake, is a madder lake of an orange hue, va¬ rying from yellow to rose-colour and brown. Madder purple, Purple ruinate, or Field's purple, is a very rich and deep carmine, prepared from mad¬ der. Though not a brilliant pur¬ ple, its richness, durability, trans¬ parency, and superiority of colour, have given it the preference to the purple of gold purple, and to burnt carmine. Madder yellow is a preparation from the madder-root. The best is of a bright colour, resembling Indian yellowq but more powerful and transparent, though hardly equal to it in durability of hue; metallic, terrene, and alkaline substances acting on and reddening it as they do gamboge: even alone, it has by time a natural tendency to change in appearance. Mceniana, seats in the upper porticoes of the Roman forum, from whence spectators witnessed the combats of gladiators. Magnase black is the best of all blacks for drying in oil without addition, or preparation of the oil: 269* MAH MANNER. man it is a colour of vast body and tingeing power. Mahogany is a native of the West Indies and the country round the Bay of Honduras. It is said to be of rapid growth, and so large that its trunk often exceeds 40 feet in length and 6 feet in diameter. Spanish mahoganyis importedfrom Cuba, Jamaica, Hispaniola, St. Do¬ mingo, and some other of the West India Islands, in logs from about 20 to 26 inches square and 10 feet long. It is close-grained and hard. There is also African mahogany. All the species are used for many purposes, more particularly for su¬ perior household furniture. Main links , the links in the parallel motion which connect the piston- rod to the beam of a steam-engine. Mainmast of a ship, a long piece of round timber, upright in the waist or middle of a ship. Malleable , in metallurgy, capable of being spread by heating or by rolling,—a distinguishing character of metals, but more especially of gold. When flattened, it is said to be laminable ; when drawn as wire, ductile. Manacaybo is a furniture w’ood of moderate size, hard, as good as ma¬ hogany, and in appearance between that and tulip-wood. Manchineel, a large tree of the West Indies and South America: it possesses the general character of mahogany, but has a poisonous and unwholesome sap. Mandril, the spindle which carries the centre-chuck of a lathe, and communicates motion to the metal to be turned: in small lathes it is driven by a pulley. Mandril-frame, the head-stocks or frame bolted to the end of a lathe- bed, for the purpose of supporting the mandril. Mangrove, an aquatic tree, straight¬ grained, hard, and elastic : much used for ship-building. Man-hole, an opening in the top of a boiler, used as an entrance when the boiler requires cleaning : it is covered by a strong plate bolted to the boiler plating, so as to be steam- tight. Man-hole cover, a strong plate of iron, bolted over the man-hole so as to be removable when required. Manipulation, in mining, the manner of digging silver or other metals; a term now generally applied to the means by which materials or effects are produced. Manner is that habitude which paint¬ ers have acquired, not only in the management of the pencil, but also in the principal parts of painting, —invention, design, and colouring. It is by the manner in painting that a picture is judged to be by the hand of Titian, Tintoret, Guido, the Caracci, and others. Some masters have had a variety in their manners at different periods of life, and others have so constantly adhered to one manner, that those who have seen even a few of them will imme¬ diately know them, and judge of them without any risk of a mistake. The variety observable among ar¬ tists in their manner and taste arises from the practice of the dif¬ ferent schools in which they have received their instructions, or of the artists under whom they have stu¬ died. Yet there are many instances of great artists who have divested themselves of that early partiality to a peculiar manner, and have altered it so effectually as to fix on one abundantly more refined and better adapted to their peculiar genius, by which means they have arrived at excellence. Thus, for instance, Raphael proceeded, and acquired a much more elevated manner after he had quitted the school of Perugino. Mannerist, a term applicable to a painter whose pictures have no re¬ semblance to the beautiful varieties i of nature,but discover an unpleasing and tasteless sameness. Manometer, an instrument intended to measure the rarefaction and con- 270* L MASONRY. MAN densationof elastic fluids in confined circumstances, whether occasioned by variation of temperature or by actual destruction, or generation of portions of elastic fluids. Mansard roof, of French origin, from the name of the inventor; a curb roof. Manse, a parsonage-house. Mansum capitale, the chief mansion, manor-house, or court of a lord. Mantelpiece, a beam across the open¬ ing of a fire-place, serving as a lintel or bressummer to support the masonry above, which is called the chimney-breast. Maple-wood is considered to be allied to the sycamore or the plane-tree ; its colour is pale : much used for picture-frames and Tunbridge ware. Marble, a kind of stone found in great masses, and dug out of pits or quarries. Marcus, a large iron-headed hammer. Margin, or Lock-rail, the flat part of the stile and rail of framed work. Marine engine, a steam-engine to pro¬ pel a ship. There are various kinds of them, the beam, direct-acting, oscillating, trunk, high-pressure as used in our new gun-boats, etc. (See Murray’s work, Vols. 80 and 81, in the ‘ Rudimentary Series.’) Market. The market or forum in the cities of antiquity was different from the market in our English towns, where flesh meat, merchan¬ dise, etc., are usually sold. The Apostle Paul disputed with philo¬ sophers in the market at. Athens : this and other evidences prove it to have been also a place of dispu¬ tation and public resort. Marline, a small line used for winding round ropes and cables. Marmoration, a building with marble. Marone is of a class of impure colours, composed of black and red, black and purple, or black and russet pigments, or with black and any other denomination of pigments in which red predominates. Marone lake is a preparation of mad¬ der, of great depth, transparency, MAS and durability of colour: it works well in water, glazes and dries in oil, and is in all respects a good pigment: its hues are easily given with other pigments, but it is not much used. Marquetry, chequered or inlaid work ; work inlaid with variegation, a sort of veneering, representing flowers, birds, and other figures. Masaccio, of the Florentine School, a very eminent painter, and distin¬ guished for his foreshortenings and colouring. He died in 1443. Masonry. The early Roman archi¬ tecture, both in public and private buildings, was of far more durable materials, and of more accurate masonry than such as was executed in the decline of the Empire. It began to be uncemented blocks of stone, passed into the reticular work of the Republic, thence into the travertine, and descended into the mixture of tufo, and brick, and stucco facing. Marble is polished by being first rubbed with grit-stone, afterwards with pumice-stone, and lastly with emery or calcined tin. Marbles, with regard to their contexture and variegation of colour, are almost in¬ finite : some are black, some white, and some of a dove colour : the best kind of white marble is called statuary, which, when cut into thin slices, becomes almost transparent, which property the other kinds do not possess. Other species of mar¬ ble are streaked with clouds and veins. The texture of marble is not altogether understood, even by the best workmen ; but they generally know upon sight whether it will receive a polish or not. Some mar¬ bles are easily wrought, some are very hard, other kinds resist the tools altogether. Artificial marble, or Scagliola, is real marble pulver¬ ized and mixed with plaster, and is used in columns, basso-rilievos, and other ornaments. The chief kind of stone used in London is Portland stone, which 271* MAS MATTER. MAX comes from the island of Portland, in Dorsetshire ; it is used for build¬ ings in general, as strings, window¬ sills, balusters, steps, copings, etc., but under great weight or pressure it is apt to splinter, or flush at the joints. When it is recently quar¬ ried, it is soft and works easily, but acquires great hardness in course of time. St. Paul’s cathedral and Westminster bridge are construct¬ ed of Portland stone. Purbeck stone comes from an island of the same name, also in Dorsetshire, and is mostly employed in rough work, as steps and paving. Yorkshire stone is also used where strength and durability are requisites, as in paving and coping. Ryegate stone is used for hearths, slabs, and covings. Mortar is used by masons in ce¬ menting their works. (See Brick¬ laying, Cements, Mortars, etc.) In •setting marble or fine work, plaster of Paris is used, and in water-works, tarras is employed. Tarras is a coarse mortar, durable in water and in most situations. Dutch tarras is made of a soft rock- stone, found near Cologne, on the Rhine. It is burnt like lime, and reduced to powder by mills, from thence carried to Holland, whence it has acquired the name of Dutch tarras. It is very dear, on account of the great demand for it in the construction of aquatic works. An artificial tarras is formed of two parts of lime and one of plaster of Paris: another sort consists of one part of lime and two parts of well-sifted coal ashes. Masques, grotesque faces used to fill vacant places, on friezes, panels of doors, keys of arches, etc. Mast cartings, in ship-building, large timbers at the side of the mast rooms that are left deep enough to receive the cross-chocks. Mastic, a cement used for the plaster¬ ing of walls. Mastic varnish is easily prepared by digesting in a bottle, during a few hours, in a warm place, one part of dry picked resin with two parts or more of the oil of turpentine. Materiatio, according to Vitruvius, the timber-work of a roof. Materiation, felling of timber for building. Mathematics, a science which teaches to number and measure whatever is capable of it, comprised under lines,numbers, superficies,or solids. Matter and Motion. Quantities of matter in all bodies are in the com¬ pound ratio of their magnitude and densities ; for if the magnitudes are equal, the quantities of matter will be as the densities ; and if the den¬ sities are equal, the quantities of matter will be as the magnitudes: therefore, the quantities of matter are universally in the compound ratio of both. Matter. —1, Matter in general, ma¬ teriality, corporeity, corporality,ma¬ terialness, substantiality, physical condition.—2. Inorganic matter, solid matter, density, solidity, in¬ compressibility, cohesion, fluid matter, liquidity, liquidness,vapori¬ zation, specific fluids, fluids in mo¬ tion, organic matter. Maul-stick, a painter’s stick, upon which he leans his hand when at work. Mauritius, of London—1086-1108 —built the cathedral of Old Saint Paul’s. Mausoleum, a pompous funereal mo¬ nument, a costly sepulchre. Maximum and Minimum. The ex¬ tremes of temperature are no less important to the meteorologist than interesting to the general observer. They are obtained by the self-re¬ gistering thermometer. The first instrument of this kind was sug¬ gested by John Bernouilly. Several forms of thermometers were com¬ municated to the Royal Society by Lord Charles Cavendish. The next in point of time were the contri¬ vances of Fitzgerald and Crighton. Six, Rutherford, Keith,Blackadder, and Dr. Trail, greatly added to the 2 12 * ME A ME A MEASUREMENT OF EARTHWORK. stock of self-registering thermo¬ meters. There are two kinds in general use; Mr. Six’s, which is placed vertically, and Dr. Ruther¬ ford’s, which is suspended horizon¬ tally. The latter is preferable on land, and, from its simplicity, has to a certain extent superseded the former. Mear, thirty-two yards of ground in a vein of ore. Measurement of earthwork. There are many works and tables pub¬ lished to facilitate the admeasure¬ ment of earth-work, which may be reduced in practice to the follow¬ ing geometrical forms, in one or more chains in length, as the case may be. The two chains marked b and c in the section will reduce to the forms in the diagrams that follow. The dotted lines, fig. ], show the section at the largest end, next to b in the section ; and the dotted line, fig. 2, shows the sec¬ tion at the smallest end, next to a in the section. The bottom piece, c, being re¬ duced to a parallel throughout, is measured by multiplying the area of Slopes 2 to 1. Fig. 2. banks being equal, it will measure thus : 15' 0" x 57' 0" x 132' 0". * The piece b, the middle or wedge piece, being parallel horizontally only, is measured by taking one- half the vertical height : thus, 3' 6"x 87' 0" x 132' 0". The two pieces b b form the two halves of a right-angled pyramid, and are measured by multiplying the area of the end by one-third the height: therefore 7' 0" x 14'0", the slope being 2 to 1, is equal to 98' 0"; the area of the two bases j then, 1'0" x 98'0" x 44'0", gives i the cube quantity in the two. Measurement of shipping for tonnage (called the ‘new measurement’)! was regulated in the 5th and 6th of George IV. By this Act certain rules were established for ascer¬ taining the tonnage of ships, as well on shore as afloat, and of ves ¬ sels propelled by steam ; and the account of such tonnage, whenever the same shall have been ascer¬ tained according to the rules herein prescribed (except in the case of ships admeasured afloat), it is en¬ acted, shall be deemed the tonnage of such ships, and shall be repeated 273* MEA MEASUREMENT OF SHIPPING. MEA in every subsequent registry of such ships, unless any alteration shall have been made in their form and burthen, or unless it be disco¬ vered that the tonnage had been erroneously computed: and it is considered that the capacity of a ship is the fairest standard by which to regulate its tonnage ; that inter¬ nal measurements will afford the most accurate and convenient me¬ thod of ascertaining that capacity, and that the adoption of such a mode of admeasurement will tend to the interest of the ship-builder and the owner. It was enacted that the tonnage of every ship or vessel required by law to be registered shall, previous to her being registered, be mea¬ sured and ascertained while her hold is clear, and according to the following rule: Divide the length of the upper deck between the after-part of the stem and the fore¬ part of the stern-post into six equal parts. Depths : At the foremost, the middle, and the aftermost of those points of division, measure in feet and decimal parts of a foot the depths from the under side of the upper deck to the ceiling at the limber strake. In the case of a break in the upper deck, the depths are to be measured from a line stretched in a continuation of the deck. Breadths: Divide each of those three depths into five equal parts, and measure the inside breadths at the following points : at one-fifth and at four-fifths from the upper deck of the foremost and aftermost depths, and at two-fifths and four-fifths from the upper deck of the midship depth. Length: At half the midship depth measure the length of the vessel from the after-part of the stem to the fore¬ part of the stern-post, then to twice the midship depth add the foremost and the aftermost depths for the sum of the depths; add to¬ gether the upper and lower breadths at the foremost division, three times the upper breadth and the lower breadth at the midship division, and the upper and twice the lower breadth at the after division, for the sum of the breadths ; then mul¬ tiply the sum of the depths by the sum of the breadths, and this pro¬ duct by the length, and divide the final product by three thousand five hundred, which will give the num¬ ber of tons for register. If the vessel have a poop or half-deck, or a break in the upper-deck, measure the inside mean length, breadth, and height of such part thereof as may be included within the bulk¬ head ; multiply these three mea¬ surements together, and dividing the product by 92'4, the quotient will be the number of tons to he added to the result as above found. In order to ascertain the tonnage of open vessels, the depths are to be measured from the upper edge of the upper strake. To ascertain the tonnage of steam vessels, it was also further enacted, that in each of the several rules prescribed, when applied for the purpose of ascertaining the tonnage of any ship or vessel propelled by steam, the tonnage due to the cu¬ bical contents of the engine-room shall be deducted from the total tonnage of the vessel as determined by the rules, and the remainder shall be deemed the true register tonnage of the said ship or vessel. The tonnage due to the cubical contents of the engine-room shall be determined in the following manner: measure the inside length of the engine-room in feet and de¬ cimal parts of a foot from the fore¬ most to the aftermost bulk-head, then multiply the said length by the depth of the ship or vessel at the midship division, as aforesaid, and the product by the inside breadth at the same division at two-fifths of the depth from the deck taken as aforesaid, and divide the last product by 92-4, and the quotient is deemed the tonnage 274* MEA MECHANICS. due to the cubical contents of the engine-room. Measurement of standing timber.— Measure from the tree ten, twenty, thirty, etc., feet, and then plant the theodolite level : direct the tele¬ scope to the bottom of the tree, and observe the degree and tenth of depression; and to the top of the tree, the degree and tenth of elevation. When the timber has been previously felled, it is custom¬ ary, in measuring, to girt a string round the middle of the tree, and fold it twice, which will give the fourth part of the girt, and which is considered the true side of the square; then the length is mea¬ sured from the butt-end of the tree, so far up as the tree will hold half a foot girt, or, more properly speaking, quarter-girt; that is, the line six inches when twice folded. Various tables are published, to assist the timber-measurer in the performance of his duty. All tim¬ ber is bought and sold by the load, and a load is estimated at forty feet of unhewn or rough timber, and fifty feet of hewn timber, which is supposed to weigh one ton, or twenty hundredweight. Measurement of base lines, the whole of the operations connected with the execution of a trigonometri¬ cal survey of a country, require the most scrupulous care, and a large amount of skill, that the many errors which are inseparable from the instruments that are used, and the several processes that must be followed, may be dimi¬ nished as far as practicable, and the necessary precautions taken, where¬ by the corrections to the observa¬ tions and measurements may be applied, so as to produce the greatest amount of accuracy with the least alteration of the given elements. Of these processes, the primary is that which consists in the accu¬ rate measurement of the distance between two stations A and B, MEC designed to serve as the base, to which the whole extent of country intended to be surveyed, is to be referred. This measurement is generally expressed in terms of the standard of length of the country in which the operation is carried on,although the actual measurements may in the first instance have been given in terms of some other standard. It is not, however, requisite that the measurement of the base should precede the angular observations, and although generally it is first undertaken, it can be equally well done when every other portion of the work has been completed. The selection of a site for the base is a matter of considerable importance ; a level plain or ground with as little undulation as possible, and a distance varying from five to eight miles is to be preferred; the extremities of the base being suf¬ ficiently elevated (either from the nature of the ground or by the use of an artificial stage) above the surrounding country to allow 1 of other stations C and D being seen, and these should be so situated as to form well-conditioned triangles with the base A B, inasmuch as small errors in the measurement of very acute angles would produce large errors in the lengths of the sides deduced from them. It must not, however, be in¬ ferred, that a perfect level is ab¬ solutely requisite for the measure¬ ment of a base line. That situated on Salisbury Plain has now been twice measured, although there is a difference of level of 428 feet between its two extremities. Mechanical powers are contrivances by which we are enabled to sustain a great weight or overcome a great resistance by a small force. (See Machinery .) Mechanics, that branch of practical science which considers the law's of equilibrium and the motion of solid bodies ; the forces by which bodies, 275* MEC MECHANICS. MEN whether animate or inanimate, may be made to act upon one another; and the means by which these forces may be increased so as to overcome those which are more powerful. The term Mechanics was originally applied to the doctrine of equilibrium. It is now, how¬ ever, extended to the motion and equilibrium of all bodies, whether solid, fluid, or aeriform. The com¬ plete arrangement of mechanics is now made to embrace, besides, the pressure and tension of cords, the equilibrated polygon, the catenary curve, suspension bridges, the equi¬ librium of arches aud the stability of their piers, the construction of oblique arches, the equilibrium of domes and vaults with revetments, the strength of materials, whether J they he of wood or iron, dyna- j inics (or the science of moving j bodies), with hydrostatics, pneuma¬ tics. and hydraulics. Definitions are explanations of terms by means of other terms, the meanings of which are understood: we shall assume that the term weight will be accepted without explanation. s Def. Everything which has weight is called matter , and a body is a portion of matter limited in every direction. Def. Space is that which con¬ tains or is capable of containing matter, and is continuous and in¬ finite. Def. A body is said to be ab¬ solutely at rest as long as it re¬ mains in the same position in space; and to be absolutely in motion while it is _ in the act of changing its position in space. Def. A body is said to be rela¬ tively at rest as long as it remains in the same position with respect to some other body with regard to which its state is to be considered; and to be relatively in motion while it is in the act of changing its position with respect to this body. The states of rest and motion which we have generally to con¬ sider are relative and not absolute. Thus we have to consider the mo¬ tion of a locomotive relatively to the surface of the earth, and not the absolute motion made up of this and that of the earth itself, and the motions of the parts of the engine relatively to the frame of the locomotive without regard to the motion of the whole along the road. Def. Force is any cause which produces or tends to produce a change in the state of rest or mo¬ tion of a body. Forces are measured by the effects which they produce, and hence in considering effects of dif¬ ferent kinds different measures of j forces may be introduced. When a body is acted upon by only a single force, a change in its state of rest or motion will always take place; but two or more forces acting on a body at the same time may counteract each other’s effects, so that the body may be in exactly the same state as though these forces were not acting upon it. Def. Two or more forces which counteract each other’s effects are said to be in equilibrium. (From the Course of Mathematics for the use of Students at the Royal Mili¬ tary Academy, Woolwich, vol. iii.) Medallion, in architecture, any cir¬ cular tablet on which figures are , embossed; busts, etc. Mediaeval, relating to the middle ages. Member, a moulding; either as a cornice of five members, or a base of three members, and applied to the subordinate parts of a building. Mensuration is the application of the science of arithmetic to geometry, ; by which we are enabled to dis- I cover the magnitudeanddimensions I of any geometrical figures, whether y solid or superficial. To enable us to express this magnitude in deter- [ rninate terms, it is necessary to j assume some magnitude of the^ same kind as the unit, and then, by j 276* MER MERE, HAARLEMMER. MER stating how many times the given magnitude contains that unit, we obtain its measure. The different species of magni¬ tude which have most frequently to be determined are distinguish¬ able into six kinds, viz. 1. Length. — 2. Surface.—3. Solidity, or ca¬ pacity.—4. Force of gravity, com¬ monly called weight.—5. Angles. -—6. Time. Mere, or Meer, a name frequently given, in England and the Nether¬ lands, to inland lakes or sheets of fresh water, such as Windermere, Whittleseamere, Ugg-mere, So- ham-mere, in England, and the Egmonder meer, Purmer meer, and Haarlemmer meer, etc., in the Ne¬ therlands. The term is most fre¬ quently used in the latter country, where, prior to 1440, there were more than 150 meers, of which 85 occupied an area of 177,832 acres, since drained and reclaimed, in the provinces of North and South Hol¬ land ; and where also the Haarlem¬ mer meer, covering an area of 45,230 acres, is now in course of drainage. As the meers, in fen-lands, serve as reservoirs to hold a portion of the surplus rain-water falling on the district of which they form a part, their being dyked off and drained, where of considerable ex¬ tent, has most important effects on the neighbouring lands, by con¬ tracting the area of the reservoir or catch-water basin of the district. But as these drainages generally oblige improvements in the out¬ falls, their result is mostly benefi¬ cial to the other lands. The beds of the Dutch meers are from 10 to 20 feet below the level of the lowest point of the natural outfall in their districts ; consequently . they are always drained by mechanical means. Windmills have been employed to drain the land, in the Netherlands, : from time immemorial; but the drainage of the meers was not com- 277 menced until 1440, about which period windmills and draining machinery were considerably im¬ proved; and as late as 1840, wind¬ mills for draining purposes conti¬ nued in favour with the Dutch engineers, in preference to steam engines ; and at that date, 12,000 windmills were employed to drain the polders, in the Netherlands, and only five small steam-engines, the largest not exceeding 30-liorse power: the average consumption of fuel was 20 lbs. of coal per horse power per hour. In the English fens, steam had in a great measure superseded wind¬ mills for drainage purposes ; but the consumption of fuel was nearly as great as in the Dutch engines. In 1839, the Dutch States-Ge- neral decreed the drainage of the Haarlemmer meer, and voted eight millions of florins for that purpose, to which two millions more were subsequently added, making the total sum of .£834,000. The Haarlemmer meer forms part of the great drainage district of Rhynland, which has an area of 305,014 English acres : prior to 1848, this area was occupied by 56,609 acres of meers and water¬ courses, nearly all in communica¬ tion with each other, forming what is called the boezem, or catch-water basin of the district; the surface of the water being maintained at the lowest level of natural sluiceage, by sluices at Katwvk into the North Sea, and at Spavndam and Halfweg into the Y, or the southern end of the Zuvder Zee. Above the boezem are 75,357 acres drained into it by natural level; and at depths from 2 feet 6 inches to 4 feet below it are 170 polders covering an area of 135,850 acres; and 37,198 acres, divided into 28 polders which were for¬ merly meers. but are now drained, and whose beds are on an average 14 ft. below the level of the boezem. The surplus rain and infiltration MER MERE, HAARLEMMER. MER waters from the 173,048 acres of polder-land are lifted into the boe- zem by the united action of 261 large windmills, with an average force of 1500-horse power. The drainage of the Haarlemmer meer, which forms part of the boe- zem or basin, will deduct 45,230 acres from its area, and reduce it to 11,379 acres, or ^th part of its former size : whilst the land surface drained into it will be increased from 229,657 to 293,735 acres. The average level of the boezem is 10 inches below the ordinary low water, and 27 inches below high-water mark in the Y or Zuy- der Zee; and 7 inches above low water, and 57 inches below ordi¬ nary high water, in the North Sea. The bed of the Haarlem Lake is 14 feet below the winter level of the boezem; and when drained, the maximum lift will be 16 feet 6 inches to 17 feet, according to the state of the wind, which raises or depresses the surface of the wa¬ ter in the canals very considerably. The water contents of the Haar¬ lemmer meer to be pumped out, including the additional quantity arising from the surplus rain and infiltration during the draining, are estimated at 800,000,000 cubic metres or tons. The greatest quantity of monthly drainage when the meer is pumped out is estimated at 36,000,000 tons, and the annual average surplus of rain-water, etc., at 54,000,000 tons to be lifted, on an average, 16 feet. The Dutch engineers were gene¬ rally in favour of windmills, or a combination of windmills and steam-engines, for pumping out the meer; but in 1841, the late king, William II., by the advice of a commission, decreed that steam- engines only should be employed for the purpose; and in 1842, at the suggestion of two English en¬ gineers, Mr. Arthur Dean and Mr. Joseph Gibbs, it was determined to erect, and they were directed to prepare the designs for, three steam-engines upon the high pres¬ sure, expansive, condensing prin¬ ciple, of the ordinary force of 350- horse power each, but capable of being worked on emergencies up to 500-horse power. The consumption of fuel was limited to 2£ lbs. of coal per horse pow-er per hour. The three engines were named the ‘ Leeghwater,’ ‘Cruquius,’ and ‘ Lynden,’ after three celebrated men who had at different periods proposed plans for draining the Haarlemmer meer. The ‘ Leeghwater ’ was the first erected, to work eleven pumps of 63 inches diameter, wdth 10-feet stroke in pumps and steam cylin¬ ders ; and the ‘ Cruquius ’ and ‘ Lyn¬ den ’ were afterwards constructed, to work eight pumps each, of 73 in. diameter, and with 10-feet stroke ; each engine is calculated to lift 66 cubic metres of water per stroke. The accompanying sketch is a representation of the interior of the ‘ Lynden ’ engine and engine- house, on the upper floor: the ‘ Cruquius ’ is on the same model; but the ‘ Leeghwater ’ has the inner ends of its eleven pump-beams ar¬ ranged under the great cross-head, instead of over it. Each engine has two steam cy¬ linders, placed concentrically, the one within the other, the outer of 12 feet diameter, and the inner one of 7 feet diameter: both are secured to one bottom, and covered by one cover, but the inner cylin¬ der does not touch the cover within 1^ inch: there are two pistons, 26 inches deep, the com¬ partments of which are fitted with cast-iron plates: the outer piston is annular, and has a packing on both sides: beneath this annular piston a constant vacuum is main¬ tained when working: the two pis¬ tons are connected by five piston- rods, as shown in the sketch, to a great cross-head or cap, the whole 278 MER MERE, HAARLEMMER. MER the action of the engines is therefore very simple : the steam being ap¬ plied under the inner piston, lifts both the pistons, the great cross¬ head, and inner ends of pump ba¬ lance-beams simultaneously, and the pump-pistons descend at the same time: by an hydraulic apparatus attached to the great cross-head, the deadweight of the pistons, etc., is arrested at the point to which it has been thrown up by the steam, and time is given for the valves of the pump-pistons to close before the down-stroke of the steam-pis¬ tons is made ; then, the equili¬ brium-valve being opened, the hy¬ draulic apparatus is liberated at the same moment, and the steam passing from beneath the small pis¬ ton, above both pistons, the pres¬ sure on both sides of the small one is equalized, whilst nearly two- thirds of the steam acts upon the annular piston against a vacuum, and in aid of the dead weight helps to make the down-stroke in the steam-cylinder, and the up¬ stroke in the pumps. The use of the two cylinders enables the en¬ gine-man, by judiciously altering the expansion in the small cylinder, to command his work at all times, without stopping the engine to take out, or put in, dead weight, as would be necessary for a single- acting one-cylinder engine, where dead weight only is used for lifting the water. It has frequently oc¬ curred that the load of an engine has been added to or diminished by 10 or 12 tons in the course of half an hour, by the action of gales of wind on the surface of the meer and boezem. Each engine has two air-pumps of 40 in. diameter, and 5-feet stroke. The steam is cut off in the small cylinder at from one- fourth to two-thirds of the stroke, according to the load; and after expanding through the remainder of the stroke, it is still further ex¬ panded in the large cylinder. The anticipated economy in con¬ sumption of fuel has been realized: when working with the net power of 350horses,the average consump¬ tion is lbs. of best Welsh coals, or 75 millions duty with 94 lbs. of coal; and on a late trial, the ‘ Cru- quius ’ and ‘ Lynden ’ engines were found to do a duty of 87 millions. The whole cost of machinery, buildings, coals, and wages, to pump out the lake, will not exceed £150,000, whereas, by wind it would have cost £308,000, being a saving of £158,000; and there will also be a further economy upon the works in the bed of the lake, amounting to £40,000 more, so that the total saving by steam over •wind will be £200,000, and three years’ time. To compensate the district of Rhynland for the loss of 45,230 acres of the boezem or catch-water basin, a steam-engine of 200-horse power, driving 10 large scoop- wheels, has been erected at Sparn- dam to lift the boezem water over the tide in the Y, or base of the Zuyder Zee, where the rise is on an average only 17 inches. This engine has discharged 30,000,000 tons of water in fifteen consecutive days. When the state of the boezem permits the ‘ Leeghwater,’ ‘ Cru- quius,’ and‘Lynden’ engines to work freely, they discharge on an aver¬ age 2,000,000 tons in twenty-four hours, and they are capable of doing this down to their full depth. In the month of June, 1849, the three engines discharged 60,000,000 tons water, and lowered the meer one foot; between the 1st of May and 1st of December they had lowered the lake 5 feet, and by the autumn of 1850 dry land appeared. (See Table.) The ‘Leeghwater,’ ‘Cruquius’and ‘ Lynden ’ engines were contracted for jointly by the Hayle and Per- ran Foundry Companies, Cornwall, and were manufactured and erected under an able director. This once formidable meer is now 280 MERES, DRAINAGE OF. Table, arranged chronologically, showing the Lakes, Meers, and Water-places which have been drained by mechanical means, and converted into Fertile Lands, in the Provinces of North and South Holland, in the Netherlands. NORTH HOLLAND. SOUTH HOLLAND. 'd <3 .5 § c 0 rt . Name of Lake. bn Name of Lake, •iz fcb Meer, or Water- Location near. a ^ Meer, or Water- Location near. gw age. place. l.s place. < .2 1440 Nesch Meer Wervershoofd 59 1460 Burghornder Do. Burghorn 684 1553 The Zyp Schagerbrug 19026 1555 Egmonder Meer Egmond 10080 1560 Berger Do. Bergen 1394 Daal Do. Koedyk 285 1561 Vrooner Do. St. Pancras 246 1566 Achter Do. Alkmaar 78 1567 Kooi Do. Do. 33 Zwyns Do. Oudorp 38 1580 Boekeler Do. Akersloot 745 1607 Wog Do. Spierdvk 1541 1608-12 The Beemster Purmerend 16369 ,, The Weiring- ^ erwaard j Colkom 3979 1614 Soetermeersche \ Meer J Soetermeer 1285 1616 Tjaarlinger Meer Warmenhuizen 98 161 S -22 Purmer Do. Purmerend 6260 1622 The Lisserpoel Lisse 533 1624 BaarsdorperDo. Berkhout 401 Hem Meer Sassenheim 149 TheEnge Wor- \ Near Worme- 1 241 99 mer J meer / 1625 The Hr. Hu- \ gowaard J Langendyk 6904 „ Broeker Meer { Broek & Wa- \ ter-land / 638 1625-28 Belmer Do. Monnikendam 310 Buikslooter Do. Buiksloot 772 1626 The Groot Waal Berkhout 138 1626^29 Wormer Meer Gisp 3786 Diemer Meer Diemen 1575 1630 Benning Do. Abbekerk 245 „ Harger & Pet- 1 temer Polder / Petten (O 00 *^1 1631 The Tien Meeren Haring Garspel 4647 „ The Drie Do. Oud Garspel 730 ,, Kley Meer Koedyk 147 Kerk Do. Do. 48 Deble Do. Warmenhuizen 31 Greb Do. Do. 201 „ The Vier *> Meertjes J Medenblyk 680 Braak Meer Eerstwoude 69 Veenhuizer Do. Veenhuizen 718 1632 Schals Do. Knollendam 145 Schremer Do. N. & S. Schermer 12938 1633 The Vier \ Meertjes J Obdam 142 1636 Berk Meer Veenhuizen 596 1640 Kolk Do. { Lambert Scha- gen j 220 1642 Slooter Meer 199 1643 Star Do. Oostgrafdyk 1447 1644 Noordeinder Do. Graft 409 1645 Sap Do. The Ryp 52 1646 The Wilde } Veneen f Moerkapel 1322 1650 Stom Meer Aalsmeer 409 281 MERES, DRAINAGE OF. NORTH HOLLAND— continued. J s SOUTH HOLLAND— continued.. -c y ; c ® 2 * P a Date of Name of Lake, \ Name of Lake, Drain¬ age. Meer, or Water- place. Location near. a Meer, or Water- place. Location near. eS r “ vensche Do. J Oudshoorn 1318 1768-71 TheGroote Do. Soeterrneer 1686 Do. Do. Stompwyk 1178 1772-77 Berkelsehe Do. Berkei 2171 1772-82 Bleiswyksche \ Drainage / Bleiswyk 8299 1773-80 Schiebroksche Polder / Shibroek 145/ 1781-84 Vendeer en \ Lyker Do. / Alkemade 1373 1782-89 Pynaker.cke Do. Pynacker 12/0 1786-88 Aarlander- 1 veensche Do. J Aarlanderveen 1171 1788-91 Zesfcienho- 1 vensche Do. J Overschie 1064 1788-99 Schieveensche 1 Do, J Ovcrschie 654 1790) 1810 j M\ drechtschc 1 Do. I Mydreeht 2622 1797^ Nienekoopsche") en Zevenho- V Niewekoop 1571 1809 j venesche Do. j 1798-99 Gnephoek en ■> Vrowe Do. / Oudshoorn 254 17997 Bieslandsche Do. Nootdorp 333 1810 Kleine Slarre- \ vuartscheDu. 1 Leydschendam 23 1820 Bylmer Meer Weesp 1470 1828-40 The Zuid Plas Rotterdam 14820 1842 Nootdorpsclie \ Delft 2500 Haarlem Lake'! Amsterdam, "1 1840-50 (not yet com- > Haarlem and > 45230 pleted) J Leyden J 124505 98557 98557 In North Do. Do. Total Acres 223062 282 MERIDIAN. MER a drained district, and is most pro¬ fitably occupied by industrial agri¬ cultural pursuits. It may be said in this instance, the Dutch have realized the fable of the ‘ Hare and the Tortoise: in 1840, the erection of a steam- engine of 30 or 40-horse power, for drainage purposes, was thought to be a bold step, whereas, under the guidance of English engineers, they have dared, between 1840 and 1842, to erect the most gigantic steam machinery in the world. The low lands of the Nether¬ lands are divided into large drain¬ age districts, which have been em¬ banked against the inroads of the tides and river floods; and the va¬ rious parts of a district are con¬ nected by what is called the boezem, or water-basin, or reservoir, formed by the rivers,lakes, meers, or water- places having their origin in the district, and serves to receive the water drained either naturally or artificially from the surrounding lands. The boezem is put into communication with the exterior waters of the rivers or sea by locks and sluices. All lands in a given drainage district above the level of the boezem, and draining naturally into it, are called ‘ boezem lands.’ All lands lying below the boezem, and drained into it by machinery, are called polders. Of polders there are two kinds: the first are seldom more than 2 or 3 feet below the level of the boezem, which is em¬ banked above the natural surface of the land : of such polders there are upwards of 1000 in the pro¬ vince of South Holland only; and they are kept dry by the aid of an immense number of windmills. Of the second class of polders there are 43 in North Holland and 43 in South Holland, as recorded in the precedingTable,and these are works of a formidable character, being, for the most part, the beds of lakes, or permanent sheets of water, varying in depth from 5 to 20 feet below MES the boezem, and requiring powerful machinery to pump them out in the first instance, and to maintain them dry afterwards; and as these lakes, etc., always form part of the boezem, or reservoir, of a much larger tract of land, their drainage frequently involves the construction of immense works, and seriously affects the prosperity of the whole district in which they are situate. The preceding Table will, as an apt illustration of the subject of draining large districts, be found important in engineering history. By the Table it will be seen that the North Hollanders had effected the drainage of nearly all their lakes, etc., as early as 1645, and they had then recovered 98,557 acres of land forming their beds ; whereas the South Hollanders had in 1645 only drained five small lakes, whose area was only 3741 acres. It must be observed that the South Holland drainages are of a much more extensive character than those of North Holland, and the difficulties to be overcome were much greater; and last, but not least, the North Hollanders were much richer than their neighbours. Of the 223,000 acres of lakes, etc., recorded in the Table, upwards of 50,000 acres were formed artifi¬ cially, by dredging the peat pulp to the depth of 10 or 20 feet, to serve as fuel for domestic pur¬ poses, etc. Meridian, in astronomy, the line drawn from the north to the south, through the zenith, nadir, and poles, which line the sun crosses at noon. Merlon, the solid part of an embattled parapet, standing up between the embrasures. Merus, the plain surface between the channels of a triglvph. Mesaula, a passage, gallery, or lobby; an entry or court. Messuage ,a dwelling-house,with some land adjoining, as garden, orchard, etc., and all other conveniences be¬ longing to it. 283 METALS. MES Mestling, brass ornaments ; candle¬ sticks ; sacred utensils used in Anglo-Saxon times. Metallurgy, the art of working me¬ tals, invented by Tubal-Cain, b. c. 3608. “And Zillah also bare Tubal- Cain, an instructor of every arti¬ ficer in brass and iron.” {Gen. iv. 22.) In the earliest periods of his¬ tory, mention is made of the ex¬ cellence in working metals among the Egyptians. Some specimens of metal-work of an early date ex¬ ist, and modern fashion has also produced some very elaborate ex¬ amples. Metals are elementary bodies capable of combining with oxygen ; and many of them, during this combi¬ nation, exhibit the phenomenon of combustion. Seven metals only were formerly known; but recently a much greater number has been added. Metals are distinguished by their great specific gravity, con¬ siderable tenacity, and hardness, opacity, and property of reflecting the greater part of the light which falls on their surface, giving rise to metallic lustre or brilliancy. Me¬ tals are the best conductors of caloric: their expansibilities are various, and are probably nearly in the order of their fusibilities. Mer¬ cury melts at so low a temperature, that it can be obtained in the solid state only at a very low tempera¬ ture; others, as platina, can scarcely be melted by the most intense heat which we can excite. Metals employed in the mechanical arts .— Antimony is of a silvery white colour, brittle, and crystalline in its ordinary texture: it fuses at about 800°: its specific gravity is 6'712. Bismuth is a brittle, white me¬ tal with a slight tint of red : its spe¬ cific gravity is 9 - 822: it fuses at 4 7 6°, and always crystallizes on cooling. Copper is the only metal, with the exception of titanium, which has a red colour: it has much lustre, is very malleable and ductile, and MET exhales a peculiar smell when warmed or rubbed: it melts at a bright red or dull white heat, or at a temperature intermediate be¬ tween the fusing points of silver and gold= 1996° Fahr.: its specific gravity varies from 8‘86 to 8 - 89,— the former being the least density of cast copper; the'latter, the great¬ est of rolled or hammered copper. Gold is of a deep and peculiar yellow r colour; it melts at a bright red heat, equivalent, according to Daniell, to 2016° Falir., and when in fusion, appears of a brilliant greenish colour: its specific gra¬ vity is 19*3: it is so malleable, that it may be extended into leaves which do not exceed the -g- 8 J oou th of an inch in thickness, or a single grain may be extended over 56 square inches of surface. Lead in colour is bluish-white : it has much brilliancy, is remark¬ ably flexible and soft, and leaves a black streak on paper. When han¬ dled, it exhales a peculiar odour: it melts at about 612°, and by the united action of heat and air, is readily converted into an oxide. Its specific gravity, when pure, is II - 445 ; but the lead of commerce seldom exceeds 11-35. Lead is used, in a state of comparative purity, for roofs, cisterns, pipes, vessels for sulphuric acid, etc. Mercury is a brilliant white metal, having much of the colour of silver. It has been known from remote ages. It is liquid at com¬ mon temperatures, solid and mal¬ leable at —40° Fahr., and contracts considerably at the moment of con¬ gelation : it boils and becomes va¬ pour at about 670° : its specific gravity at 60° is 13’5. In the solid state, its density exceeds 14. The specific gravity of mercurial vapour is 6-976. Nickel is a white brilliant metal, which acts upon the magne¬ tic needle, and is itself capable of becoming a magnet. Its magnetism is more feeble than that of iron 284 MET METALS. MET and vanishes at a heat somewhat below redness, ^.t 630° it is duc¬ tile and malleable: its specific gra¬ vity varies from 8'27 to 8'40 when fused, and after hammering, from 8'69 to 9'00. It is not oxidized by exposure to air at common tempe¬ ratures ; but when heated in the air, it acquires various tints, like steel: at a red heat, it becomes coated by a grey oxide. Palladium is of a dull white colour, malleable and ductile. Its specific gravity is about ll - 3, or 11'86 when laminated. It fuses at a temperature above that required for the fusion of gold. Platinum is a white metal, extremely difficult of fusion, and unaltered by the joint action of heat and air. It varies in den¬ sity from 21 to 21'5, according to the degree of mechanical compres¬ sion it has sustained. It is ex¬ tremely ductile, but cannot be beaten into such thin leaves as gold and silver. Rhodium, discovered in 1803 by Dr. Wollaston, is a white metal, very difficult of fusion. Its specific gravity is about 11; it is extremely hard. When pure, the acids do not dissolve it. Silver is of a more perfect white than any other metal: it has considerable brilliancy, and takes a high polish. Its specific gravity varies between 10'4, which is the density of cast silver, and 10-5 to 10’6, which is the density of rolled or stamped silver. It is so mallea¬ ble and ductile, that it may be ex¬ tended into leaves not exceeding a ten-thousandth of an inch in thick¬ ness, and drawn into wire much finer than a human hair. Silver melts at a bright red heat, estimated at 1873° Fahr., and when in fusion appears extremely brilliant. Tin has a silvery white colour, with a slight tint of yellow: it is malleable though sparingly ductile, Common tin-foil, which is obtained by beating out the metal, is not more than yJ-g-^th of an inch in thickness,and what is termed ‘ white Dutch metal ’ is in much thinner leaves. Its specific gravity fluctuates from 7'28 to 7'6, the highest being the purest metal. When bent, it occasions a peculiar crackling noise, arising from the destruction of co¬ hesion amongst its particles. When a bar of tin is rapidly bent back¬ wards and forwards several times successively, it becomes so hot that it cannot be held in the hand. When rubbed, it exhales a peculiar odour. It melts at 442°, and by exposure to heat and air is gradu¬ ally converted into a protoxide. Zinc is a bluish-white metal, with considerable lustre; rather hard; of a specific gravity of about 6-8 in its usual state; but when drawn into wire, or rolled into plates, its density is augmented to 7 or 7'2. In its ordinary state, at common temperatures, it is tough, and with difficulty broken by blows of the hammer: it becomes very brittle when its temperature ap¬ proaches that of fusion, which is about 773°; but at a temperature a little above 212°, and between that and 300°, it becomes ductile and malleable, and may be rolled into thin leaves, and drawn into moderately fine wire, which, how¬ ever, possesses but little tenacity. When a mass of zinc which has been fused is slowly cooled, its fracture exhibits a lamellar and prismatic crystalline texture. The pipes of the great organ in the town-hall at Birmingham, and in that of York cathedral, are made principally of sheet zinc. Aluminium, a newly discovered metal; see p. 12. Meteorology, the term now used for the purpose of designating the sci¬ ence which observes, registers, clas¬ sifies, and compares the various and varying phenomena of our atmo¬ sphere. It remarks, at the same time, the connection of those phe¬ nomena with the heavenly bodies, N 3 285 MET METEOROLOGY. MIL and with the solid and liquid ma¬ terials of the earth, in reference to their reciprocal and combined in- fluencein determining the character of different climates, and with the view of learning the meteoric his¬ tory of every region of our globe, of ultimately investigating the laws of atmospheric change, the plan of meteoric action ; the theory, in fact, of meteorological phenomena, on which depend essentially the fit¬ ness of the various portions of the earth’s surface for the production of different vegetable and other sub¬ stances and for the support of ani¬ mal life. Meteorological phenomena are not con¬ fined to the inferior regions of the atmosphere, but extend as far as observations have reached. It is possible their influence may extend universally, and therefore it is de¬ sirable to know whether there exists throughout space a medium, or con¬ ductor, or whether there is such a thing in nature as vacuum. Some have, it is true, endeavoured to re- concile opinions so diametrically opposed to each other, by suggesting that the universe, though infinite, ’ is a plenum and a void ! This (the doctrine of Leucippus) a recent au- thor declares to be really true; and some conceive that the New¬ tonian theory necessarily implies the reality of a void, the astrono¬ mical calculations on which that theory rests having been made without any allowance for the re¬ sistance to the motions of the planets,which might be experienced from a material medium, Metoche, the intervals between two denticuli in the Ionic entablature. Metope , the spaces between the tri¬ glyphs of the Doric frieze, which in the Parthenon, for instance, were filled in with sculpture; but in modem porticoes that are said to be after the Parthenon, they are mere blanks. Metre, a French measure, equal to 39*3702 English inches. Mezuzoth, a name given to certain pieces of parchment which were anciently fixed on the door-posts of houses. Mezzanine, a low intermediate story between two higher ones. Mezzo-relievo, projection of figures between alto- and basso-relievo; demi-relievo. Mezzotinto, a kind of engraving nearly resembling painting, effected bv scraping and burnishing the copper. Mica, an important ingredient in the composition of rocks, consisting of silica, alumina, oxide of iron, and potash: it is easily divided into laminae, even to the eooVoo^ P art of an inch, and is distinguishable from talc by its elasticity : in Russia it is used instead of window-glass. Micrometer, an instrument for mea¬ suring small spaces. Microscope, an optical instrument for rendering visible minute objects: the simple microscope has one lens only, and magnifies by permitting a near view of the object; in the compound microscope, a focal image is again magnified by other lenses. Middle-ground is a term used, not to express the middle of a picture, but generally perspectively so ;--some- times it is the highest part of a picture, and sometimes the second degree of shade. Pictures are di¬ vided into three parts : fore-ground, middle-ground, and back-ground. Middle-rail, the rail of a door which is upon a level with the hand when hanging freely : the lock of the door is generally fixed in this rail. Midship signifies the middle of a ship. Midship-bend, the broadest frame in the ship, called the ‘ dead-flat. ’ Milestones. Pliny says, the miles on the Roman roads were distinguished by a pillar, or a stone, set up at the end of each of them, and which was marked with one or more figures, signifying how far it was from the Milliarium Aureum, a pillar in the forum near the temple of Saturn, which had on it the figure I., so that the next pillar to it, which was 286 MIL MILLS. MIN marked II., was but one mile from the standardpillar,and consequently the XIV. and XI. stones were hut thirteen and ten miles from the forum. Our London Stone was probably the Milliarium Aar turn of the Roman city. MUliare, a Roman mile, consisting of 1000 paces of 5 feet each, and therefore = 5000 feet; taking the Roman foot at 116496 English inches, the Roman mile would be 1618 English yards, or 142 yards less than the English statute mile. Mills for the grinding of grain into flour are of several kinds ; wind¬ mills, with sails to be impelled by the action of the wind, over-shot and under-shot; and the horizontal or turbine water-wheels. Mill machinery is used for the grinding of tobacco into snuff, impelled by wind, particularly in Holland, where stupendous structures can be seen on the road from Rotterdam to the Hague. Mills are also used, pro¬ pelled by steam or water, for the grinding of bark, preparing of flax, sawing of timber, and for the many and varied purposes in manufacture. In the ‘ Papers on Engineering,’ vol. vi.,will be foundan interesting paper by Mr. Fairbairn on ‘ Water- Wheels with Ventilated Buckets.’ Millwrights’ Planing Machine. This machine is similar in principle to the ordinary planing machine (see Planing Machine ), except in cases where heavy work is required to be planed, when a machine with a movable tool and fixed table is used. The advantage of this ar¬ rangement is, that very large and heavy castings are planed, which could not be moved to and fro, as in the ordinary machines, without great loss of power. It is placed over a pit made for the purpose, with steps to descend into it. The two side frames are bolted to the ground, and the table has a series of apertures for bolts to fix the work upon it, and can be raised or lowered to any required height by four strong screws, one at each corner. The horizontal and ver¬ tical slides are placed over the work in the usual manner, and are at¬ tached to a light frame, which, when the tool is adjusted to the work by the vertical slide, is moved to and fro, carrying with it the slides and tool, and at the end of each backward stroke a lappet, or other contrivance, sets the vertical slide and tool a little further across the table, until the entire surface is planed. Mmaret, in Mohammedan architec¬ ture, a spire or steeple. Mineral Black is a native and impure oxide of carbon, of a soft texture, found in Devonshire. Mineral Green is the commercial name of green lakes, prepared from the sulphate of copper. Mineralogy forms one of the three great divisions into which natural history or the knowledge of natu¬ ral objects has been classified ; the other two being botany, devoted to plants, and zoology, to animals. Mineralogy is also distinguished from geology, inasmuch as it re¬ gards the characters of minerals in detail, without regard to their formation and general distribution in the crust of the earth, winch belong to geology. If the compo¬ sition of a mineral substance is to be considered, then mineralogy forms a portion of chemistry ; but in its more limited sense, mine¬ ralogy is the art of distinguishing mineral substances from each other, and the science of accurately de¬ scribing and arranging them, by what may be termed a natural clas¬ sification. Minercu in a speech expresses to Juno her resentment at the restraint put upon her by Jupiter. She accuses him of forgetting the services she had so often rendered to Hercules when he was oppressed by the la¬ bours that Eurystheus had laid upon him, and declares that it was 287 MIN MINES. MIN she who effected his escape from Hades. (Gladstone.) Minerva, in her capacity of a tradi- tive deity, was with perfect consist¬ ency worshipped alike among Tro¬ jans and Greeks, Hellenic and Pe- lasgian tribes ; there is nothing strange, then, in our finding her the patroness of a Pelasgian peo¬ ple. (Gladstone.) Mine. In a general sense the word mine is an opening underground from which anything is dug, and it appears to be derived from the Latin minare, a word of the lower ages, signifying ducere, to lead ; hence to draw or lead a way or passage underground. Until the opening is made, the term mine is not properly applied ; although it is generally used to signify the coal, iron, lead, &c., before the opening is made for digging them out. Mining, in its proper sense, was certainly carried on in Britain before the Roman conquest and during the Roman occupation. After the Romans had abandoned Britain, this art, in common with many others, fell into decay, the necessary consequence of civil com¬ motion. For a long period our mines were worked by foreigners, and after the Norman Conquest, chiefly by Jews. In the reign of Elizabeth, the Germans, who had long been celebrated as skilful miners, had inducements held out to them to settle in this country, which they appear to some extent to have done. In the following reign, Sir Hugh Myddelton ex¬ pended the revenue which he de¬ rived from some lead and silver mines in Cardiganshire, in supply¬ ing London with fresh water by means of the New River. About this time the introduction of gun¬ powder into mining operations led to many decided improvements. The first use of this powerful agent is said to have been made in 1020 in Hungary or Germany, and in the same year it was introduced into England at the copper mine at Ecton,in Staffordshire, by some German miners brought over by Prince Rupert. It was not, how¬ ever, used in Cornwall until a considerably later period. Mines. Water-springs in mines are wrongly considered to be of great injury. It is true, the lifting of water by machinery from the deep mines is attended with expense, when they are so situated that no level, drift, or watercourse can be obtained for that purpose ; but, on the other hand, they are so abso¬ lutely necessary in mining, that in the very first process, a judicious miner, in boring down to his mine, previous to his sinking to or work¬ ing it, even in this simple act, cannot proceed very deep without water to work his bore-rod in; and if the strata of the earth passed through does not produce it, he must pour it down the hore hole, or he cannot proceed. When all his pits or shafts are sunk, and his mine opened, and ventilation is re¬ quired to expel inflammable air, fire, or black damp (as it is termed), nothing is superior to water. When this can be obtained, and made to run with facility through the mine and its various workings, it is found superior to air-furnaces of any kind for expelling the fulminating va¬ pours so destructive to health. Mining. There is an essential differ¬ ence between civil and military mining: in the former, the works are frequently carried on at consi¬ derable depths below the surface of theearth, and sometimes in solid rock; whereas military mining is what may be termed superficial, and consequently the miner works through the more recent formations of earths and sands, which, from their little tenacity, he has to sup¬ port as he advances. For the bet¬ ter ventilation of military mines, a machine has been invented by Ser¬ geant Lewis, of the Royal Sappers and Miners ; and it has been con- 288 MIXED COLOURS. MOD MIN jectured that Mr. Haig’s patent pneumatic engine, invented for the purpose of purifying the holds of vessels, might also be successfully employed in mining operations. Minster, a cathedral, anciently a large church. (See Westminster Abbey.) Minute, a proportionate measure in architecture, by which the parts of the orders are regulated; the six¬ tieth part of the lower diameter of the shaft of a column, written thus, 10', i.e. ten minutes; in geography and astronomy, the sixtieth part of a degree. Miserere, projecting brackets in the under side of the seats of stalls in churches; they are always more or less ornamented with carvings of leaves and grotesque subjects. Mitre, an episcopal crown. In carpen¬ try, the line formed by the meeting of mouldings or other surfaces which intersect each other. If two pieces of wood be formed to equal angles, or if the two sides of each piece form equal inclinations, and thus be joined together at their common vertex, so as to make an angle double to that of either piece, they are said to be mitred together, and the joint is called ‘ the mitre.’ Mitre-wheel, a wheel having teeth formed so as to work at an angle of 45° to the centre line of the shaft on which it is fixed, to move with another wheel of equal size, fixed on a shaft at right angles to the former one Mixed Citrine. There are two prin¬ ciples of combination, of which the artist may avail himself in pro¬ ducing these colours; the one being that of combining two original se¬ condaries, green and orange, in pro¬ ducing a citrine; the other, the uniting the three primaries in such a manner that yellow may predomi¬ nate in the case of citrine, and blue and red be subordinate in the com¬ pound. Mixed Greys are formed by the compounding of black and white, which yields neutral greys, and of black and blue, black and purple, black and olive, etc. Mixed Greens, compounds of blue and yellow pigments, which may be formed by compounding them in the several ways of working, or by blending them in the propor¬ tions of the various hues required. Mixed Olive is compounded by unit¬ ing green and purple colours, or by adding to blue a smaller proportion of yellow and red, or by breaking much blue with little orange. Mixed Orange. Orange being a colour compounded of red and yellow, the place of original orange pigments may be supplied by a mixture of the two latter colours, by glazing one over the other; by stippling, or other modes of breaking and intermixing them in working, ac¬ cording to the nature of the work and the effect required. Mixed Purple. Purple being a se¬ condary colour, composed of blue and red, it follows of course that any blue and red pigments which are chemically at variance may be used in producing a mixed purple of any required hue, either by compounding or by grinding them together ready for use, or by com¬ bining them in the various modes of operation in painting. Mixed Russet. Orange, vermilion, and madder purple atford a com¬ pound russet pigment of a good and durable colour. Mizen-mast, in ship-rigging, the mast next the stern. Mock lead, wild lead, black lead, or black jack, a ponderous black mi¬ neral, which does not readily in¬ corporate in the fire ; a zinc ore. Model, a pattern used for moulding; a machine or building executed in miniature. Modillion, a projecting bracket under the corona of the Corinthian and Composite orders, and sometimes of the Roman Ionic. Module, a measure of proportion by which the parts of an order or of a 289 MOL MONASTERIES. MON building are regulated in classical architecture ; considered generally as the diameter or semi-diameter of the lower end of the shaft of the column ; in other words, semi¬ diameter of the column, or 30 mi¬ nutes. Molecule, synonymous with atom, in physics, a very small mass or por¬ tion of any body. Molybdenum, a brittle and white glo- bulous metal. Momentum, in dynamics, is the force of a body in motion. When the motion of a body is considered with respect to the mass, or quantity of matter moved, as well as its ve¬ locity, it is called its momentum, or quantity of motion. The mo¬ mentum of a body is therefore in the compound ratio of its quantity of matter and velocity. Monastery, an establishment for the accommodation of a religious fra¬ ternity, who made it the receptacle of benevolence and charity for the poor and the way-worn. A con¬ siderable portion of the land was formerly occupied by the monas¬ teries and other religious houses which existed in Britain, and the endowments of these establish¬ ments subsequently became the foundation of the great wealth of some of the early aristocracy in England. Of the ample means enjoyed by the inmates of these cloistered sanc¬ tuaries, some idea may be formed from the following historical state¬ ment, translated from the preface to the ‘ Ely Cartulary,’ preserved in the Public Library at Cambridge. After the defeat and death of Harold, many of the leading men of the realm, who had strenuously opposed the Bastard, fled for re¬ fuge to Ely monastery, together with their friends, “ laden with their richest treasures,” and with¬ stood, for seven years, the im¬ petuous threatenings of the Nor¬ mans, until they were unexpectedly surprised. “ Then a council being held, it seemed advisable to implore the royal mercy; upon which some were despatched to the king’s court, at that time at Warwick, carrying rich treasures to the king, the gift of atonement and compen¬ sation of their misconduct; with which the king was satisfied, but on these terms and conditions,— that, during his pleasure, forty royal officers should be lodged at the expense of the monastery. * * The knights are sent for, they arrive, and are present with their household, every one of whom has under him a monk of the first order, as an officer under his earl, or a guest under his host. But the king ordered that the cellarer should dispense provisions to the officers and monks promiscuously in the public hall of the convent. In short, the officers with their earls, the guests with their hosts, the knights with their monks, the monks with their knights, were most grateful to each other; for each and all of them mutually afforded each other the offices of humanity.”—After five years passed in this way, the knights were re¬ called by the Conqueror, to assist in punishing the unnatural wicked¬ ness of his son Robert; and “ they departed with grief; and our monks, wonderful to relate, lamented the departure of these most illustrious companions, heroic knights, and most pleasing guests, not only in tears, but in dismal howlings and exclamations, and struck their breasts in despair, after the man¬ ner of a bride whose husband is unseasonably hurried from her sweet embraces to arms. . . All the monks accompanied the knights as far as Haddenham, with hymns, crosses, thuribals, processions, and every solemnity, and, when re¬ turned, took care to paint the arms of each knight on the walls of the refectory, to the perpetual remem¬ brance of the uncommon humanity of their military guests.”—In the 220 MON MORTAR. MOR cartulary the names of the knights, forty in number, with their com¬ panions, are given ; and their arms are emblazoned on the margin. Monkey-wrench , a spanner with a movable jaw, which can be adjust¬ ed by a screw or wedge to the size of the nut which it is required to turn. Monogram , a cipher composed of two or more letters interwoven as an abbreviation of a name: monograms were common as distinctive marks on ancient coins, and were also used as seals. Monolithic, consisting of a single stone ; statues, columns, and pillars were formed by the ancients out of large blocks of stone or marble. Monopteral, a temple which has no cella, but consists of columns dis¬ posed in the form of a circle, co¬ vered with a conical roof. Monota, a vase with one handle. Monotriglyph, the interval observed between the columns of a Doric portico, where a space is left suf¬ ficient for the insertion of one tri- glvph only between those imme¬ diately over two contiguous co¬ lumns. Monstrance, sometimes called Remon¬ strance, the vessel in which the consecrated wafer or host is placed while the congregation are blessed with it, in the Roman Catholic Church. In the ‘ Divers Works of Early Masters,’ 2 vols. folio, will he found two of the rarest and most elaborate examples of tabernacles or canopies, in a compartment of either of which the casket or vessel containing the sacred vessel is de¬ posited. Monton, a heap of ore : a batch under process of amalgamation, varying in different mining districts. Monument, a mausoleum or tomb. Sepulchral monuments of the mid¬ dle ages still exist to a considerable extent, both here and on the Con¬ tinent. Monuments and tombs of modern date are designed from Classical and Gothic architecture, and in many instances are beautiful examples of modern art. Moor, in Cornish, a root, or quantity of ore in a particular part of a lode, as a ‘ moor of ore,’ a ‘ moor of tin.’ Moorish, Mohammedan, or Saracenic Architecture, is a combination of Egyptian, Grecian, and Roman de¬ tails ; first established by the Arabs about the tenth century, and for oriental scenery of a pleasing cha¬ racter: its complicated ornament and lattice-work are rich and pecu¬ liar. Many existing examples are interesting; but the style is not adapted to European usages and requirements. Moot-hall, or Moot-house, in Saxon times, a building appropriated to assemblies on public affairs; a guild¬ hall or town-hall; hotel de ville, etc. Mora wood. This tree is 100 feet high, and abundant; it is close- grained, like teak, and superior to oak ; esteemed for ship-building. Moresque, a kind of painting, carving, etc., in the arabesque and grotesque styles of ornament. Mortar. The materials which are added to lime, in the formation of mortars or calcareous cements, are, 1st, the different kinds of sand, properly so called; 2nd, arenes; 3rd, psammites; 4th, clays; 5th, volcanic or pseudo-volcanic pro¬ ducts ; and 6th, artificial products arising from the calcination of the clays, the arenes, and the psam¬ mites ; and the rubbish and slag of manufactories, forges, etc. INGREDIENTS OF MORTAR. Sand. —The granitic, schistose, and calcareous rocks, free-stones, etc., reduced to the state of hard and palpable grains, either by the agitation of water, or by spontane¬ ous disaggregation, give birth to the various kinds of sand. We dis¬ tinguish them from powders by their falling at once to the bottom, when thrown into limpid water, and that without altering its trans¬ parency in any sensible degree. 291 MO 11 MORTAR. MOR The disaggregation of rocks is often accompanied by a decompo¬ sition which produces a powder: this powder renders the sand ‘ rich,’ or, in other terms, susceptible of a certain cohesion, when tempered with water. Washed by rains and currents of water, it is soon freed from the pulverulent particles, and is deposited pure in the beds of rivers. This purity is often changed near the mouths of streams, and in the small rivulets whose tributaries flow over a bed of clay or mould: the sand mixes with vegetable de¬ bris and animal matters, and be¬ comes ‘ loamy.’ The particles com¬ posing sand faithfully represent those of the rocks whence they are derived. The granitic regions furnish quartz, felspar, and mica; and the volcanic regions, lavas of all kinds. The tabular-shaped sands, whose particles are tender, are furnished by the schistose mountains. It is difficult for them to be transported far without be¬ ing reduced to powder. The calcareous sands are the least common, probably arising from the fact that rivers generally take their rise from primitive sum¬ mits, or such as are composed of primitive elements. The calcare¬ ous rocks, besides, are not suscep¬ tible of that kind of disaggregation which can be called granitic; for if they be of a soft kind, they produce powder; if hard, scaly splinters. The partial and secondary revo¬ lutions of the globe have occasioned immense deposits of sand in situa¬ tions where now neither brooks nor rivers flow: these are the fos¬ sil sands ; and they should be care¬ fully distinguished from the virgin sands, which are still in their origi¬ nal site, and have not been operated on by the waters. The fossil sands generally exhibit a more angular grain than the sea or river sands ; but consist for the most part of the same elements, sometimes pure, sometimes coloured by ochres, etc. Among the fossil sands is one very remarkable, the arene. Its properties entitle it to attention. Arene is a sand, generally quartzose, with very irregular, un¬ equal grains, and mingled with yellow, red, brown, and sometimes white clay, in proportions varying from one to three-fourths of the whole volume. The arene almost always occu¬ pies the summits of the rounded and moderately-elevated hills: it sometimes constitutes entire hil¬ locks ; frequently it interposes it¬ self in large veins and seams in the clefts of calcareous rocks: it be¬ longs essentially to alluvial soils. Psammites is a term applied to an assemblage of the grains of quartz, schist, felspar, and particles of mica, agglutinated by a variable cement. The varieties of these are very numerous: those which in appearance strongly resemble the free-stoues and siliceous breccias belong to the class of rocks whose disaggregation furnishes sand, pro¬ perly so called. But the psam¬ mites, which are slaty, of a yellow, red, or brown colour, fine-grained, unctuous to the touch, producing a clayey paste with water, form a distinct species, and one which merits attention. These last belong to the primi¬ tive schistose formations : they do not and cannot exist except in situ: they are found in beds or veins, forming part of the schist of w r hich they are merely a decomposition. Clays are earthy substances va¬ riously coloured, fine, soft to the touch, which diffuse in water with facility, forming with it a paste, which, when kneaded to a certain consistency, possesses unctuosity and tenacity, and may be drawn out and kneaded in every direction without separating. The clayey paste, when dried, retains its soli¬ dity, hardens in the fire, etc. 292 MOR MORTAR. MOR Clays are essentially composed of silica and alumina: these two substances are adulterated by the presence of the oxide of iron, the carbonates of lime and magnesia, sulphuret of iron, and of vegetable combustible matter partly decom¬ posed. The clays are separated into four classes : viz. the refractory, which resist, without melting, the heat of the porcelain furnaces (140° Wedg¬ wood) ; the fusible clays; the ef¬ fervescing or clayey marls; and, lastly, the ochrey clays, coloured red or pure yellow by oxide of iron. The position of clays is very va¬ ried : they are found as veins in pri¬ mitive formations; in hillocks, on the confines of the primitive chains; in horizontal beds, or layers, in the secondary formations ; in threads, thin veins, or infiltrations, in chinks and hollows of calcareous masses ; lastly, in volcanic regions, where their formation is attributed to the decomposition of the compact lavas, and perhaps also, with some proba¬ bility, to miry eruptions. Mortar. Considered as a plastic material, mortar fit for moulding may be made to take every pos¬ sible form in moulds or shapes. To give it the appearance of stone, it should be made with fine colour¬ less sand, or rather with fine calca¬ reous powders derived from hard stones. Mortar contained in a mould may be beaten or rammed in the manner of pise,—“ a mode of building for¬ merly in use, whereby walls were formed by ramming and beating down earth, clay, etc., between up¬ right planks,”—and acquires by that means great compactness; but an increase of resistance does not always result from this. In order that any material be beaten with effect, it is necessary that it should possess a certain de¬ gree of consistency, which is a mean between complete pulverulence and that state of ductility which con¬ stitutes a firm paste. No compres¬ sion is possible when the material escapes from under the rammer; and this is still practised by the builders in pise, who never employ any but earth slightly moistened. Mortar may always be prepared in this way, leaving it, after it has been worked in the ordinary manner, to undergo desiccation to a proper extent. The successive approximation of the particles of the compressed material to one another neces¬ sarily determines a foliated struc¬ ture, which, though it may not he perceived, is nevertheless real. Analogy will lead to the conclusion, that, in every possible case, a body thus formed ought to oppose a greater resistance to a tractile force in proportion as its direction forms a smaller angle with the plane of the laminae; however, experience shows that this in general does not take place. The following has been determined in this respect:— 1st. Beating has the effect of augmenting the absolute resistance of mortars of rich limes and pure sand in every case, but in an un¬ equal manner. The greatest re¬ sistance assumes a direction per¬ pendicular to the planes of the laminae when the mortars are buried in a damp soil immediately after their fabrication. It remains pa¬ rallel to these same planes when the mortars have been exposed to the atmospheric influence. 2nd. The effect of beating is not constantly useful to mortars of hydraulic or eminently hydraulic limes, and calcareous or quartzose sands or powders, except in the case when these mortars are used under a damp soil. The greatest resistance is then in a direction perpendicular to the planes of these laminae, as with the mortars of rich limes; but in the air, the superiority of the mortars which have been beaten over those which have not is only exhibited in one direction, 293 MOR MORTAR. MOR and that is parallel to the plane of the laminae. 3rd. Beating becomes injurious in every case when the hydrates of the hydraulic or eminently hydrau¬ lic limes are employed without admixture, and subjected to the influence of a damp soil; and is favourable to it only in the direc¬ tion parallel to the laminae when the stuff dries in the air. i Considered as a plastic sub- S stance, the numerous casts which : have been moulded, both in the | bas-relief and alto-relievo, prove ; that mortar receives and retains impressions well: their hardness is continually on the increase, and t a kind of varnish, with which time covers them, gives them a strong resemblance to stone. '' One problem remains to be ! solved, viz. to discover a means of hastening the set of mortar with¬ out injuring its future qualities; and this, in order to avoid being obliged to multiply moulds indefi¬ nitely for the same casting. This : last desideratum appears to be dif¬ ficult. The natural cements, which t harden almost instantly in the air and in the water, when worked up like plaster of Paris, are subject to the inconvenience of being tinged brown. Such as are fabricated f artificially, by calcining mixtures of lime and clay free from iron, do not stand the weather. Mortar of hydraulic lime may be employed as a plastic substance in a multitude of cases, in which the number of moulds is no inconve¬ nience. Such is the case in the pre¬ paration of artificial stones bearing mouldings, vases, or ornaments of any kind susceptible of formation by the rectilinear or circular move¬ ment of a profile. It is evident that it will then answer to set the mould in a trench, and run the profile along the clayey paste, pre¬ pared and arranged for that pur¬ pose. The economy which such a process would introduce into ornamental constructions is indeed incredible. Mortise, in carpentry, a hole cut in a piece of wood, to receive a corre¬ sponding projection formed upon another piece. Mortise and Tenon. The following rules may be referred to as data for the workman in ordinary prac¬ tice. The tenon, in general, may be taken at about one-tbird of the thickness of the wood. When the mortise and tenon are to lie horizontally, as the juncture will thus be unsupported, the tenon should not be more than one-fifth pf the thickness of the stuff, in order that the strain on the upper surface of the tenoned piece may not split off the under-cheek of the mortise. When the piece that is tenoned is not to pass the end of the mor¬ tised piece, the tenon should be reduced one-third or one-fourth of its breadth, to prevent the necessity of opening one side of the tenon. As there is always some danger of splitting the end of the piece in which the mortise is made, the end beyond the mortise should, as often as possible, be made considerably longer than it is intended to re¬ main ; so that the tenon may be driven tightly in, and the super¬ fluous wood cut off afterwards. But the above regulations may be varied, according as the tenoned or mortised piece is weaker or stronger. The labour of making deep mor¬ tises, in hardwood, maybe lessened, by first boring a number of holes with the auger in the part to be mortised, as the compartments be¬ tween may then more easily be cut away by the chisel. Before employing the saw to cut the shoulder of a tenon in neat work, if the line of its entrance be correctly determined by nicking the place with a paring chisel, there will be no danger of the 294 MOULDINGS. MOU ! MOS wood being torn at the edges by the saw. As the neatness and durability of a juncture depend entirely on the sides of the mortise coming exactly in contact with the sides of the tenon, and as this is not easily performed when a mortise is to pass entirely through a piece of stuff, the space allotted for it should be first correctly gauged on both sides. One half is then to be cut from one side, and the other half from the opposite side; and as any ir¬ regularities which may arise from an error in the direction of the chisel will thus be confined to the middle of the mortise, they will be of very little hindrance to the exact fitting of the sides of the mortise and tenon. Moreover, as the tenon is expanded by wedges after it is driven in, the sides of the mortise may, in a small degree, be inclined towards each other, near the shoulders of the tenon. M-roof \ a roof formed by the junction of two common roofs with a vallum between them. Mosaic (The) books, and the other historical books of the Old Testa¬ ment, are not intended to present, and do not present, a picture of human society, or of our nature drawn at large. Their aim is to exhibit it in one master relation, and to do this with effect, they do it, to a great extent, exclusively. The Homeric materials for exhibit¬ ing that relation are different in kind as well as in degree; but as they paint, and paint to the very life, the whole range of our nature and the entire circle of human action and experience, at an epoch much more nearly analogous to the patriarchal time than to any later age, the poems of Homer may be received in the philosophy of hu¬ man nature, as the complement of the earliest portion of the sacred records. (Gladstone.) Mosaic-work, the art of picturing with small pebbles and shells of various colours, pieces of glass, marble, etc., cemented on a ground of stucco. Mosque, a Mohammedan temple. Motif, that which suggests a hint or idea to an artist; also the hint itself. Motion. The cross-head, cross-head guides, and blocks, in a locomotive engine, taken as a whole, are called “ the motion.” Motion (laws of). A body must con¬ tinue for ever in a state of rest, or in a state of uniform and rectili¬ neal motion, if it be not disturbed by the action of some external cause. The alteration of motion produced in a body by the action of any external force is always proportional to that force, and in the direction of the right line in w'hich it acts. The action and re¬ action of bodies on one another are equal, and are exerted in op¬ posite directions. Motion of bodies on inclined planes. The force of an inclined plane bears the same proportion to the force of gravity as the height of the plane bears to its length; that is, the force which accelerates the motion of a body down an inclined plane, is that fractional part of the force of gravity which is repre¬ sented by the height of the plane divided by its length. Mould, the model or pattern used by workmen as a guide in working mouldings and ornaments, in the casting of metal, and models of machinery. Mouldings, a term applied to all the varieties of outline or contour given to the angles of the various subordinate parts and features of buildings, whether projections or cavities, such as cornices, capitals, bases, door or window jambs, and heads, etc. There are eight sorts of regular mouldings, viz. the Ovolo, the Talon, the Cyma, the Cavetto, the Torus, the Astragal, the Scotia, and the Fillet. These mouldings are not to be used at 295 MOULDINGS. MOU hazard, each having certain situ¬ ations adapted to its reception, to which it must always be applied. Thus the ovolo and talon, from their peculiar form, seem intended to support other important mould¬ ings or members; the cyma and cavetto, being of weaker contour, should only be used for the cover or shelter of other parts ; the torus and astragal, bearing a resemblance to a rope, appear calculated to bind and fortify the parts to which they are applied; the use of the fillet and scotia is to separate one mould¬ ing from another, and to give a variety to the general profile. The MOU ovolo and talon are mostly placed in situations above the level of the eye; when below it, they should only be applied as crowning mem¬ bers. The place for the scotia is universally below the level of the eye. When the fillet is very wide, and used under the cyma of a cor¬ nice, it is termed a corona; if un¬ der a corona, it is called a band. The curved contours of mould¬ ings are portions of either circles or ellipses. The principal mouldings, and the difference of their profiles in the Grecian and Roman styles, are here exhibited. Moulding, the process of forming a cavity in sand or loam, in order to give its form to metal which is ap¬ plied in a fluid state ; an ornamen¬ tal cavity in wood, stone, or other suitable material. Mountain-blue. A very beautiful sub¬ stance of this kind, a carbonate of copper, both blue and green, is found in Cumberland. None of these blues of copper are, how ever, durable; used in oil, they become 29G MOU music' green, and, as pigments, are pre¬ cisely of the character of verditers. Mountain-green is a native carbonate of copper, combined with a white earth, and often striated with veins of mountain-blue, to which it bears the same relation that green ver- diter does to blue verditer; nor does it differ from these and other copper-greens in any property es¬ sential to the painter. M. S., an abbreviation commonly used on tomb-stones or monumental tablets for the Latin words Me¬ mories Sacrum, ‘ Sacred to the Me¬ mory’: the letters I.H.S. are often similarly applied in sacred edifices, for Jesus Hominum Salvator ,— ‘ Jesus the Saviour of Men.’ Mud-holes, the covered openings in the bottom of a boiler for discharg¬ ing the dirt and sediment. Mud-plugs, in locomotive engines tapered screw-plugs fitted into con¬ venient parts of the boiler, to admit of its being washed out by these plug-holes when necessary. Mulberry-tree, a wood of great va¬ riety, principally from Rio Janeiro, and very suitable for furniture. Mullion, the division between the lights of windows, screens, etc., in Gothic architecture: the styles or upright divisions in wainscoting are also sometimes called mullions. Mule-jenny, a machine used in the manufacture of cotton thread. Mun (Cornish), any fusible metal. Mundick, an exceedingly ponderous mineral, whitish, beautiful and shining, but brittle. It is abundant in Cornish and Irish mines. Muniment-house, a strong, properly fire-proof apartment in public or private buildings, for the preser¬ vation of charters, deeds, seals, etc. Munniohs, pieces that part the lights in a ship’s stern and quarter-gallery. Munnions, in house-building, upright posts that divide the lights in a window-frame. Mummy, or Egyptian-brown, is a bituminous substance, combined MUS with animal remains brought from the catacombs of Egypt, where liquid bitumen was employed three thousand years ago in embalming, in which office it has been com¬ bined, by a slow chemical change, during so many ages, with sub¬ stances which give it a more solid and lasting texture than simple asphaltum; but in this respect it varies exceedingly. Mural, pertaining to a wall; a monu¬ mental tablet affixed to a wall is a mural monument. Murometer, an instrument to measure small spaces. Murus, the wall of a Greek city, in contradistinction to Paries, the wall of a house, and Maceria, a boundary wall. Music. This word is derived from the Latin musica, and this again from the Greek adjective mousikos, which signifies, of or belonging to the Muses. As a substantive, the word mousikos, or in Latin musicus, a musician, means also a poet or an orator: and in the feminine gender signifies the liberal arts, but especially music, poetry, and elo¬ quence. The ancients, therefore, understood by music far more than has been attributed to it for some ages past. Music is now considered as the language of agreeable sounds, and is both a science and an art. As a science, it teaches the theory of musical sounds, their production by the vibrations of the air, the ratio of these vibrations, and also their times; likewise the various phenomena connected with musical sounds, the causes of discords, beats, etc., as well as the lengths of mu¬ sical strings and pipes. The ma¬ thematical theory of music is part of the science of acoustics, or phonics, and is therefore one of the high mechanical sciences. As an art, music teaches the practical use of the science; the scales or gamuts of sounds in a fixed succession, at fixed intervals from each other; the permutations of their sounds; form- 297 NAOS. MUS ing an immense variety of melodies. It teaches also the combination of these sounds according to certain received laws, forming thereby the most agreeable sensations on the ear, by producing a great variety of chords, composed of concordant sounds alone, or of a judicious ad¬ mixture of concordant and dissonal sounds. Practical music teaches also the use and performance of the several instruments of music, as also their peculiar functions; and herein is embraced the human voice, the most perfect and beautiful of all musical instruments. Music, therefore, is divided into two grand parts, viz. theoretical or scientific, and practical; the former treating of the purely philosophical branch mathematically, the latter being confined solely to the production of musical compositions, and their per¬ formance. Practical music consists of several species, the highest of which is the ecclesiastical; then follow the oratorio, opera, military, chamber,and ball-room species; and NAP is divided into vocal and instru¬ mental music, each of these being variously subdivided. Musnud, in Persia, a throne or chair of state. Mustaib, a wood from the Brazils, inferior to rosewood, but harder; used at Sheffield for the handles of glaziers’ and other knives, etc. Mutule, a projecting block worked under the corona of the Doric cor¬ nice, in the same situation as the modillions in the Corinthian and Composite orders ; it is often made to slope downward towards the most prominent part, and has usually a number of small guttae or drops, worked on the under side. Mynchery, the Saxon name for a nun¬ nery : nuns were sometimes called Mynchies. Myoparo , a small piratical craft, em¬ ployed by the Saxon corsairs. Myriad, the number of 10,000 ; pro¬ verbially any great number. Myriametre, a French measure of 10,000 metres. N. Nails, used in building, are small metallic spikes serving to bind or fasten the parts together. There are several kinds of nails, called by numerous names. In the middle ages, nails were frequently used much ornamented, of which there are several very beautiful existing specimens, particularly in church doors and the gates of large man¬ sions. Naked, of a column or pilaster, the surface of the shaft where the mouldings are supposed to project. Naked, of a wall, the remote face whence the projectures take their rise. It is generally a plain sur¬ face, and when the plan is circular, the naked is the surface of a cy¬ linder, with its axis perpendicular to the horizon. Naked flooring, in carpentry, the whole assemblage or contignation of timber-work for supporting the boarding of a floor on which to walk. Naked flooring consists of a row of parallel joists, called floor- joists. Naos, the chamber or enclosed apart¬ ment of a Greek temple. The part of the temple which stood before the naos, comprehended between the wall and the columns of the portico, was called the pronaos; while the corresponding part be¬ hind was called the posticum. Naples yellow is a compound of the oxides of lead and antimony, an¬ ciently prepared at Naples under the name of Grallolina; it is sup¬ posed also to have been a native production of Vesuvius and other volcanoes, and is a pigment of de¬ servedly considerable reputation. It is not so vivid a colour as patent yellow and turbith mineral, but is 298 NAP NASMYTH’S MACHINES. NAT variously of a pleasing, light, warm golden-yellow tint. Like most other yellows, it is opaque, and in this sense is of good body. It is not changed by the light of the sun, and may be used safely in oil or varnish, under the same man¬ agement as the whites of lead; but like these latter pigments also, it is likely to change even to black¬ ness by damp and impure air when used as a water-colour, or unpro¬ tected by oil or varnish. Naphtha, a species of mineral oil or fluid bitumen, now commonly used for lamps. Narthex, a division in the early Christian churches in which the catechisms were said, and peni¬ tents admitted ; it was near the entrance, and separated from the rest of the church by a railing or screen. Nasmyth'spatent direct-actionsteam- hammer is employed instead of the old helves or lift-hammers, and is worked by a connected high-pres¬ sure steam engine, which raises the hammer to any required height within its vertical range of motion, and in which it is guided by two planed guides. On the escape of the steam, when the valve of the cylinder is opened, the hammer falls on the work that lies on the anvil with the full force due to gravity, without scarcely any loss from friction. The instant the hammer has given its blow, the steam is again let in under the piston, and the same action is re¬ peated with ease and rapidity. Nasmyth’s steam pile-driving engine. There are two grand or important features of novelty in this pile¬ driving engine, compared with all former contrivances for the like purpose. In the first place, by the employment of the steam-hammer action, the steam is made to act direct in raising up and letting fall the hammer, or monkey, without the intervention of any rotatory mo¬ tion ; while, in the second place, another grand feature consists in the employment of the pile about to be driven, or raised up and planted in its situation by the ma¬ chine, by means of a windlass wmrked by a small detached steam engine. Some conception of the rapidity with which piles are driven by this machine may be formed, when it is stated that a pile measuring 60 feet in length, and 14 inches! square, can be driven 45 feet into | stiff soil, down to the rock below, in | four minutes ; and such is the good effect resulting from the blows being given by a great mass of 30 cwt. striking quickly but with small velocity of actual impact, that the head of the pile requires no hoop, and presents, after being driven, a neater appearance than it had when it was first placed under the hammer. Natural beds of stone are the surfaces from which the laminae are sepa¬ rated. It is all-important for the duration of stone walls, that the laminae should be placed perpendi¬ cular to the face of the work, and parallel to the horizon. Natural Philosophy takes an exten¬ sive range, embracing the study of the collection of created beings and objects, and of those laws by which they are governed, all of them expressed in the term Nature. Natural objects are separated into two grand classes, the organic and inorganic; the former being dis¬ tinguished by vital power or life: organic bodies admit of a marked distinction into animals and plants ; the science of Zoology describing and classifying the one, and that of Botany the other. These sciences admit of many subdivisions, and collectively with Mineralogy, that of Natural History. 1. Geology, the science which has for its object the observation and description of the structure of the external crust of the globe; Mine¬ ralogy taking account only of the NAVE. NAT separate items of which the earth’s crust is composed. 2. Chemistry, which may be regarded as atomic anatomy, its object being to de¬ compose bodies, to study the pro¬ perties of their elements, and the laws of combination. 3. Physics, or Natural Philosophy, which con¬ siders the general properties of all bodies. Natural philosophy is again subdivided into many dis¬ tinct sciences. The mutual action of forces and masses of matter produces in the latter either equi¬ librium or motion, and hence arise those two divisions of sciences, called Statics and Dynamics, which are again divided into Stereo-statics and Stereo-dynamics, as applied to solids; Hydrostatics and Hydro¬ dynamics, as applied to liquids; Electro-statics and Electro-dyna¬ mics, as applied to Electricity. The application of statics and dy¬ namics to air and other gaseous fluids is called Pneumatics. The application of dynamics to the arts of life has led to the composition and arrangement of the various machines for assisting the labour of man : this branch is called Me¬ chanics. The construction and per¬ formance of the various machines to raise water, or which are dri¬ ven by the motion of that fluid, belong to hydrodynamics, while the construction of works depend¬ ing on the equilibrium of liquids belongs to hydrostatics. Those machines which are driven by the wind depend on the application of pneumatics; and all the varied phenomena of the atmosphere arising from the action of heat, light, electricity, and moisture, form the science of Meteorology. The phenomena of heat and elec¬ tricity also form separate sciences; the latter admitting of five divi¬ sions, viz. electricity, magnetism, galvanism or voltaic electricity, thermo-electricity, and animal electricity. The phenomena of light, although included in the NEA term Optics, are varied; namely, perspective, catoptrics, dioptrics, chromatics, physical optics, and polarization; to which may be added actino-chemistry. Naumachia, among the Greeks, a sea-fight; a spectacle. The term was also applied to a circus encom¬ passed with seats and porticoes, the pit of which, serving as an arena, was filled with water by means of pipes, for the exhibition of sea-fights. Naupegus, a shipwright. Nautical, pertaining to shipsor sailors. | Naval Architecture, the art of de¬ signing and constructing ships and j vessels for the purposes of naviga¬ tion. Navale, a ship-dock or dockyard. Navalia, ship-building docks at Rome, \ where also ships were laid up and refitted. Navarchus, among the ancients, the I name of a commander or admiral of a fleet. Nave, the body of a church west of the choir, in which the general congregation assemble. In large buildings it consists of a central division, with two or more aisles; and there are frequently, in foreign structures, several small chapels on the sides beyond the aisles. In mechanics, the central part of a wheel. Navel-hoods, in ship-building, pieces of plank, or thick stuff, wrought above and below the hawse-holes. Navis, in church furniture, a metal dish or vessel to contain frankin¬ cense. Neap, low, decrescent; a term applied to the tides which happen when the moon is in the middle of her second and fourth quarters. The highest spring-tide is three days after the full or change ; the lowest neap-tide is four days before the full or change. Neapolitan School of painting, which possesses indisputable proofs of having in ancient times ranked among the first in Italy; as in no 300 NEA NEAPOLITAN SCHOOL. NER part of that country do the re¬ mains of antiquity evince a more refined taste, nowhere do we find mosaics executed with more ele¬ gance, nor anything more beautiful than the subterranean chambers which are ornamented with his¬ torical designs and grotesques. At the restoration of art, it had made little progress in Naples and her territories before Zingaro's time. His name was Antonio So- lario, originally a smith, and com¬ monly called to Zingaro. His his¬ tory has something romantic in it, like that of Quintin Matsys. The most celebrated work ^)f Zingaro’s was in the choir of S. Severino, in fresco, representing in several compartments the life St. | Benedict. He left numerous pic¬ tures, and Madonnas of a beautiful form, in various churches of Naples, —in that of S. Domenico Maggiore, where he painted a Dead Christ, and in that of S. Pier Martire, where he represented a S. Vincenzio. Two eminent artists of the Nea¬ politan School were Matteo da Siena and Antonella da Messina. The latter is a name so illustrious in the history of art, that he claims notice in the Sienese, Neapolitan, and Venetian Schools. It has already been observed that at the commencement of the sixteenth century, the art of paint¬ ing seemed in every country to have attained to maturity, and that every school assumed its own peculiar character. Naples hovrever did not possess a manner so decided as j that of other schools in Italy. A writer has observed that no part of Italy could boast of so many native artists. Their rapidity of execution was another effect of their genius, a quality which has been alike praised by the ancients and the moderns, when combined with other more requisite gifts of genius. But this despatch in general excludes cor¬ rect design, which from that cause is seldom found in that school. Nor do we find that it paid much at¬ tention to ideal perfection, as most of its professors, following the prac¬ tice of the naturalists, selected the character of their heads and the attributes of their figures from common life; some with more, and others with less discrimina¬ tion. With regard to colour this school changed its principles in con¬ formity to the taste of the times. The modern Neapolitan School is founded on the schools of Raffa- ello and Michelangiolo. The chief names are Andrea Sab- batini, Polidoro Caravaggio, Marco da Siena, Corenzio, Ribera Carrac- ciolo, Luca Giordano, and Solimene. Nebule moulding, an heraldic term. In architecture, an ornament of the zigzag form, but without angles: it is chiefly found in the remains of Saxon architecture, in the archi- volts of doors and windows. Neck of a capital, the space between the astragal on the shaft and the annuletof the capital in theGrecian- Doric order. Neck-mould, in architecture, a small convex moulding surrounding a column at the junction of the shaft and capital. Necrology, an obituary formerly kept in churches and monasteries. Needle, or Nail, in mining, a long taper piece of copper or iron, with a copper point; used when stamp¬ ing the hole for blasting, to make by its insertion an aperture for a fusee or train. Needlework, a term anciently used for the framework of timber and plaster in old houses. Neo, a Greek term, to spin or twist a number of separate fibres of wool or flax into a single thread. Ne plus ultra (Latin), the extreme of anything. Nervures, nerves or branches, a term applied by Prof. Willis, of Cam¬ bridge, to the ribs of a vaulted roof which bound the sides of any groined compartment. 301 NET NICHE. NON Net, or Neat, in commerce, that which is pure and unadulterated; the weight of any package after the tare has been deducted: some¬ times, but improperly,written nett. Newel, the central column round which the steps of a circular stair¬ case wind; the principal post at the angles and foot of a stair¬ case. In the Tudor and Elizabe¬ than residences very beautiful ex¬ amples exist, adding much to the beauty of the staircase. Niche, in architecture, a cavity or hollow place in the thickness of a wall, in which to place a figure, a statue, vase, or ornament. Niches are made to partake of all the seg¬ ments under a semicircle : they are sometimes at an equal distance from the front, and parallel or square on the back with the front line, in which case they are called square recesses, or square niches. Occasionally small pediments were formed over them, supported on consoles, or small columns or pi¬ lasters placed at the sides of the niches. Anciently they were used in ecclesiastical buildings for sta¬ tues and shallow square recesses. The ruins of Palmyra exhibit niches of various kinds. Within the por¬ tico of the temple of the Sun there are two niches, etc. Niche, angular, one formed in the corner of a building. Niche, in carpentry, the wood-work to be lathed-over for plastering. The usual constructions of niches in carpentry are those with cylin¬ drical backs and spherical heads, called cylindro-spheric niches, the execution of which depends upon the principles of spheric sections. Niche, ground, that which, instead of bearing on a massive base or dado, has its rise from the ground,—as the niches of the portico of the Pantheon at Rome: their ordinary proportion is, two diameters in height, and one in width. Round or square niches are also formed. Nigged ashlar, stone hewn with a pick or pointed hammer, instead of a chisel; used principally at Aber¬ deen for the hewing of the hard granite. Nitrate of lime, nitric acid in com¬ bination with lime for a base, abounding in the mortar of old buildings. Nitrates, compounds, or salts, formed by the combination of nitric acid with alkalies, earths, and metallic oxides. Nitre, common saltpetre; in chemis¬ try, nitrate of potash. Nodus, anciently, in our cathedrals, a knot, key-stone, or boss. Nog, in ship-building, a treenail driven through the heel of the shores which support a ship on the slip. Nogs, blocks of wood cut to the form and size of bricks, and inserted in the nterior walls of apartments as holds for the joinery. Nogs or Nags, in mining, square pieces of wood piled on each other to support the roof of a mine. Nagging, a kind of brickwork carried up in panels between quarters. Nogging-pieces are horizontal boards placed in brick-nogging, nailed to the quarters in order to strengthen the brickwork. Nomades, in antiquity, wandering, rude, or savage tribes. Nomenclature, the art of naming; a vocabulary or dictionary of techni¬ cal language peculiar to any art or science. Nonagon, a figure of nine sides and of as many angles. Non-condensing Engines are those made without that part of the ma¬ chine called a condenser, and with¬ out those contrivances essential to the ordinary construction of en¬ gines that condense the vapour into fluid. In non-condensing engines the steam escapes into the atmo¬ sphere, after having acted upon the piston. The effect is measured by the excess of the pressure of the steam upon the piston, less the friction of the engine above the pressure of the atmosphere. 302 NORMAN ARCHITECTURE. NON Non-conductors, substances through which the electric fluid passes with considerable difficulty or not at all; such as glass, resin, sulphur, silk, hair, wool, the air, etc.; but these become electric by friction. Nones, in the Roman calendar, the fifth day of January,February,April, June, August, September, Novem¬ ber, December ; and the seventh of March, May, July, and October. Noria, an hydraulic machine, com¬ mon in Spain for raising water. The engine consists of a vertical wheel of 20 feet diameter, on the circum¬ ference of which are fixed buckets, for the purpose of raising water out of wells, etc., communicating with a canal below,and emptying it into a reservoir above, placed by the side of the wheel. The buckets have a lateral orifice, to receive and dis¬ charge the water. The axis of the wheel is embraced by four small beams, crossing each other at right angles, tapering at the extremities, and forming eight little arms. This wheel is near the centre of the horse-walk, contiguous to the ver¬ tical axis, into the top of which the top beam is fixed: but near the bottom it is embraced by four little beams, forming eight arms similar to those above described, on the axis of the water-wheel. In the movement of the horse or mule, these horizontal arms, acting on cogs, take hold, each in succession, of those arms which are fixed on the axis of the water-wheel, and keep it in rotation. Norma, a square for measuring right angles, used by carpenters, masons, and other artificers, to make their work rectangular. Normal line, in geometry, a phrase used for a perpendicular line. Norman Architecture. In Normandy, in the tenth century, when the Normans occupied Neustria, the churches in other parts of France were in imitation of the Roman style. The plan of the buildings came from Rome, and the round NOR arches, the pillars, and the mould¬ ings, which were employed in their construction, had the same origin. But the corrupt taste of a less civilized people covered the capitals and the portals with a crowd of such appalling images as a wild fancy was likely to suggest, and a rude hand to portray. The Normans, adopting the habitual plan and the established style, rejected the meretricious ac¬ cessories, and resolved to trust for success to the two great principles of size and elevation. The oldest of the Norman churches are the plainest, but even these aspire to dimensions which could not fail to command admiration. Their cha¬ racter is severe but sublime. At the same time, the Normans had the boldness to insist upon an ad¬ dition to their churches, which is admitted to be the grandest fea¬ ture and the chief ornament of ec¬ clesiastical buildings—the central tower. Towers had, fortunately, become an integral part of churches before the Normans began to build in Neustria, but the few towers which at that time existed in other parts of France only adorned the western end. Size, elevation, sim¬ plicity, and strength, together with the central tower, are the archi¬ tectural peculiarities to which the Normans, as contradistinguished from the Franks, possess unde¬ niable claims. Norman workmanship was, at first,remarkable onlyfor its solidity. The walls were often built of rubble, faced with small squared stones, —a manner of building which had been copied from the works which the Romans had left behind them in France. The pillars were, of course, composed of larger blocks. By degrees, and in buildings of importance, larger blocks were em¬ ployed in the walls; but the joints were wide, and the mortar was coarse. In the time of William the Conqueror, greater neatness o 2 303 NOR NORMAN ARCHITECTURE. NOR S was accomplished; the stones were squared, and the courses regular ; but the joints were still rather wide, and the mortar unsifted. Another mode of construction was with long, narrow stones, which were placed, not in hori¬ zontal courses, but alternately in¬ clined to the right and left. This, from the appearance it presented, was called the herring-bonefashion. It did not remain in use much after the eleventh century. The Norman walls were of great thickness, and were filled up with small stones, amongst which mortar was poured in hot. This was called grouting; and in time the whole mass so hardened together as to ac¬ quire the consistence and strength of a solid rock. Such walls stood in no need of buttresses, through the means of which more advanced science afterwards obtained an equal amount of power at less labour and less expense. Buttresses, however, appear on the exterior of early Nor¬ man buildings, but seem to have been introduced only to relieve the baldness of the surface. They pro¬ ject so slightly that they can add but little support. In early Nor¬ man buildings the buttresses never rise above the cornice. The plan of the early Norman churches is always that of the basilica, with a semicircular recess at the end, which recess formed the choir. The larger churches have transepts and side aisles which are divided from the naves by ar¬ cades. The small churches have often neither side aisles nor tran¬ septs. The arches of the nave either rest on piers, to which half- pillars are attached, or on single pillars, but hardly ever on those huge cylindrical piers which are commonly seen in the Norman churches of England. Indeed, the thick cylindrical piers of England are scarcely to be met with in all France, except in one or two crypts, where the known superincumbent weight justifies the preference of strength to beauty. In the churches of France, single pillars preceded piers; the exact reverse of what might have been expected, were it not recollected to what an extent and degree France had become Roman, previous to the inroad of the Northern con¬ querors. The pillars have always capitals, which, at first, w'ere per¬ fectly plain ; but, from the begin¬ ning of the eleventh century, were enriched with different kinds of foliage, to a certain degree depart¬ ing from, but still seeking to imi¬ tate, the Roman models. The half¬ pillars, which are attached to the ends of the piers, are always set back in recesses, or sinks ; the same is the case with the small pillars on the outside of the windows, as also with those of the portals. This is a characteristic difference between the Norman style and the Roman, •—the Norman pillars are recessed, the Roman project. The windows are always round- headed and undivided, and, exter¬ nally, have on each side a small ! recessed pillar, which supports an impost and moulding. In the gable, over the entrance door of churches, a small circular i window is sometimes introduced. The windows of castles and of | domestic buildings are usually di¬ vided bv a single shaft. The portals are round-headed, ! and w'ere gradually enriched by an increasing number of semicircular ‘ mouldings. The most common mouldings are the billet, the nail- head, the chevron, the zigzag or embattled frette, hatchet, nebule, star, rope, beak-head, dog-tooth, and, occasionally, different sorts of foliage, as the vine, the bay, the ivy. etc. (See Frontispiece.) The external cornice, under the eaves of churches, was sometimes a moulding describing a series of • semicircles, under a projecting course, and sometimes a series of 304 ANGLO-NORMAN ARCHITECTURE. NOR blocks. The ornamented corbels, on the exterior of churches, were adopted by the Normans before imagery was admitted into the in¬ terior of the edifice. The roofs of the early Norman churches were of wood, except the part over the semicircular chancel, which from the first was vaulted with stone. The side aisles were also vaulted with stone ; as were, sometimes, the comparatively small naves of village churches. The vaulting was composed either of small stones let into a bed of mor¬ tar or of tufa, or of a light calca- • reous stone, which is found in many parts of Normandy. The most ancient vaulting is without ribs, and the most ancient ribs are with¬ out mouldings. The dome vaulting over the side aisles of the abbey church at Bernay is the only specimen of the kind in Normandy. The first and purest Norman style prevailed till the latter part of the reign of William the Con¬ queror, from the early part of the tenth till nearly the end of the eleventh century. The abbey church of Bernay, begun in the first half of the eleventh century, is the oldest Norman building of any conse¬ quence which remains in its pri¬ mitive form. The architecture of the interior is plain to baldness, but the dimensions are imposing. The abbey churches of Jumieges and Cerisy were begun in the first half of the eleventh century. The Norman portions of the cathedral, and of the church of St. Taurin, at Evreux, as also of the church of Mont St. Michel, belong to the same period. St. Georges de Boscherville, and the two great churches at Caen, are splendid examples of the ar¬ chitecture of the time of William the Conqueror. In all these buildings the cha¬ racter of simplicity is preserved, NOR but some ornament in the details begins to make its appearance be¬ fore the close of the Conqueror’s reign, as, for instance, in the em¬ battled frette moulding round the arches of the nave of Matilda’s church at Caen, in some parts of St. Georges de Boscherville, and other places. The florid Norman was already developed in the early part of the twelfth century. Of this style a rich specimen is afforded in the arcade of the nave at Bayeux. The arches are ornamented with a multiplicity and variety of mould¬ ings of intricate design and elabo¬ rate execution. Another specimen of the florid Norman exists in the neighbour¬ hood of Bayeux, in the church of St. Gabriel, built by Robert of Gloucester (1128). The abbey church of Monti- villiers (1117), and the church at Graville, are instances of the florid style in all its exuberance. Norman Architecture in England. Of the architecture which existed in this country previous to the intro¬ duction of the Norman there are no certain vestiges. The most competent authorities have decided that hardly anything which can be proved to be Saxon remains in existence. Parts of a few churches, which have all the marks of a very remote antiquity, and of which the style differs materially from the Norman, may be suspected to be Saxon. Their distinguishing fea¬ tures are a ruder imitation of the Roman, projecting instead of re¬ cessed pillars, and the combination of diagonal with perpendicular forms in the external ornaments of towers. Such is the case at the old church of Barton, in Lincoln¬ shire, and at Earl’s Barton, in Northamptonshire. Some persons have imagined that the generality of the Saxon churches were merely timber build¬ ings, but this appears to be a mis- 305 NOR ANGLO-NORMAN ARCHITECTURE. NOR * take ; for in Domesday Book, which takes note of 1700 churches, one, and only one, is specified as being built of wood ; and Henry of Hunt¬ ingdon, speaking of a particular church, says, “ It was not built of stone, but of wood, and covered with reeds, as is the custom in Scotland;” demonstrating that it was not the custom in England. Not only were the Saxon churches not merely timber buildings, but some of them were constructed at a considerable expense, and with much architectural ornament. In the seventh century, a church was built at Lincoln, which Bede says was of stone, and of good workmanship. The church of the monastery of Wearmouth was erected in 675, by Abbot Benedict Biscopius, a noble Northumbrian, who, at twenty-five years of age, detached himself from the service of King Oswy, and embraced a re¬ ligious life. He brought over masons from France to build his church in the Roman manner, and, when the building was nearly finished, he procured artificers from the same country, skilled in the mystery of making glass, to glaze the windows. The conventual church of Ripon, and the cathedral church of Hex¬ ham, were both built by Wilfrid, Bishop of York, in the second half of the seventh century; and were both constructed of stone, and sup¬ ported by pillars and arches. Wil¬ frid also imported builders and artists from abroad—from Rome, Italy, France, and other countries. In the eighth century, the mo¬ nastery of Croyland was built by Ethelbald, King of Mercia; and the church of St. Peter at York was rebuilt by Archbishop Albert, and consecrated just before his death, which took place in 780. Alcuin describes this church as having pillars, arches, and porticoes. In the ninth century, the pro¬ gress of the arts was interrupted by the constant incursions of the Danes. All that had been done was destroyed; and little more than repairs, and military works, could be undertaken till the peace¬ able reign of Edgar, in whose time the abbey of Ramsey was founded, and the church built by Ailwin, then alderman of all England. This church was built in six years, and finished in 974. It was in the form of a cross, and had pillars, arches, and two towers, one of which was supported by four pil¬ lars, or piers, in the middle of the building. This appears to have been the first English church that had a tower so situated, or that was built in the form of the cross. From these descriptions of the Saxon churches, preserved in the early chronicles, it appears that the Saxon style was, like that of every other country, an imitation of the Roman. The abbey church I of Ramsey, which was one of the latest, and one of the most cele¬ brated of the works of the Saxons, was completed in six years. The last Saxon work of importance was the abbey church of Westminster, built by Edward the Confessor, and finished and consecrated in 1065, one year before the Conquest. This I church is represented to have been of a different character from that of any preceding structure in Eng¬ land, and this difference undoubt- ; edly consisted in an approximation to the Norman method of building. Edward the Confessor had been brought up in Normandy, and was almost reproached for his incessant endeavours to introduce Norman customs and manners. The churches and monasteries which arose after the Conquest were constructed after a new manner of building. From all this it appears that there must have been a marked difference between the Saxon and the Norman fabrics. But, as both were an imitation of the Roman, | the difference must have consisted . 306 ANGLO-NORMAN ARCHITECTURE. NOR in the dimensions and the superior workmanship and magnificence of the new structures. It must have been the same style on a grander scale, and executed in a more sci¬ entific manner. At the time of the Conquest the Anglo-Saxons were in every respect a ruder and less civilized race than the Normans had by that time be¬ come. The earliest work of the Nor¬ mans which exists in this country was conducted by Gundulph, who, after rebuilding his cathedral at Rochester, was employed by Wil¬ liam to superintend the construc¬ tion of the White Tower, in the Tower of London, which contains within its walls perhaps the only ecclesiastical remnant of the Con¬ queror’s time at present in ex¬ istence. In the course of the Conqueror’s reign, several cathedrals, abbeys, and castles were built, none of which remain in their original state. A remnant of the Con¬ queror’s time existed at Canter¬ bury till within these few years,— the northern tower, at the west end of the cathedral. This was a part of the work of Lanfranc. The stones of which it was built were irregular, and the joints between the courses were wide. Several castles have the reputa¬ tion of being of the Conqueror’s time, but, on a close investigation, will be found to have been rebuilt in after-years. Such is the case with the castles of Norwich, Ro¬ chester, the keep at Conisborough, and many others. Within less than a century after the Conquest almost all the ca¬ thedrals and abbey churches of England, besides innumerable pa¬ rish churches, were either wholly rebuilt or greatly improved by the Normans, on whom William and his successors conferred all the best ecclesiastical preferments. By the introduction of these Norman pre¬ lates, the Norman style was rapidly diffused; at first, however, so much affected by the state of art in this country, as to give to the English building the character of a Norman building of much greater antiquity. Rufus was a great builder; his principal work was the great hall of his palace at Westminster. This hall, as it now exists, was altered by Richard II., but much of the original work was left, and during the late repairs, portions of this were visible. The lower part of the walls was faced with rubble; the courses were irregular; the joints wide. Remains of a tri- forium or gallery were discovered, which had been carried along the sides of the hall, halfway up. The capitals of the pillars on which the round arches of this gallery rested were plain cubes. The whole of the workmanship was coarse. The plan of the churches erected about this time was the same as in Normandy. All were built with the semicircular chancel, which in England afterwards fell into such general disuse that few traces of its existence are to be found in this country. It is, however, to be traced in that of St. Bartholomew- le-Grand, in London (begun in 1123), in the minster at York, at East Ham,Essex,and in otherplaces. The arches of the nave usually rested on those heavy cylindrical piers which in French churches are hardly ever to be found, except in crypts. Their prevalence in England must be ascribed to the inexpertness of the native work¬ men, and the probability is, that they had previously been adopted by the Saxons from their inability to imitate the Roman style in a more satisfactory manner. Some¬ times,to adorn the cylindrical piers, the Anglo-Normans introduced the spiral groove winding round them, with the net or lozenge - work spreading over them. The windows and the doors 307 ANGLO-NORMAN ARCHITECTURE. NOR NOR were the same as in Normandy, and the Norman mouldings were gradually introduced with little alteration. The walls are remarkably thick, and without prominent buttresses. Specimens of the time of Rufus are to be seen in the choir, side aisles, and middle transept at Dur¬ ham ; in the walls of the lower part of the western fafade of Lin¬ coln ; the towers and transept of St. Alban’s; the oldest remaining parts of Winchester; and the east end and cross aisle of Worcester. The walls in this reign were irregularly built, and the joints continued to be wide, as may be i seen at Durham, Lincoln, Winches¬ ter, and other places. The style prevailed in the early part of the reign of Henry I., as may be seen by the ruins of St. Botolph’s priory, Colchester, which was built by Ernulph, a Norman monk, in the first years of that prince. Here are the same heavy cylindrical piers, the same stumpy proportions, the same poverty of mouldings. But in the course of this reign an impulse was given to architecture by one of those men of genius who affect the character of the age in which they live. Roger Poer, Bishop of Salisbury, a Norman by birth, and combining in himself the offices and the qua¬ lities which, in those times of constant commotion, were often united, was much distinguished as a prelate, a warrior, a statesman, and an architect. William of Malmesbury relates, that the wails which were built under the super¬ intendence of Roger of Salisbury were so smooth, and had such fine joints, that they seemed to be made of a single stone. Had fine joints been in use before, their appearance in the works of this prelate would not have been so much extolled. The admiration with which they are mentioned gives us the date of the first introduction of fine joints in the walls of English buildings. From this time progressive im¬ provement took place in other parts of the fabric. Something like decoration was added. The portals began to be enriched. The architecture of England ascended to the level of the architecture of Normandy in the time of William the Conqueror. Examples of the style of this reign may be seen in the naves at Gloucester, Norwich, Ely. Durham, and Southwell; also in the lateral towers of Exeter cathedral, built by BishopWarlewast; in St.James’s tower, Bury St. Edmund’s ; in the ruins of the chapter-house at Ro¬ chester, built between 1114 and 1125, by the same Ernulph who built St. Botolph’s at Colchester, and who, on the death of Gundulph, was promoted to the see of Roches¬ ter ; in the portal of the round church at Cambridge; in the nave of the church at Dunstable ; in Saint Bartholomew-le-Grand, London, which was begun in 1123 ; in St. Sepulchre’s, Northampton, built by Simon de Liz, second earl of Northampton, on his return from the Holy Land, and who died in 1127 ; and in the abbey church of Tewkesbury, begun by Robert Fitz-Hamon (who died in 1107), and consecrated in 1123. Examples. —Portal of the chap¬ ter-house at Durham, built by Bishop Galfrid Rufus, between 1133 and 1143; church of Castle Acre priory, Norfolk, consecrated in 1148 ; church of St. Cross, Hamp¬ shire ; llipon minster; St. Frides- wide (now Christchurch), Oxford, begun not later than 1150, and finished in 1180. About this time, or a little later, Domestic architecture began to make its appearance in England, though, from the dimensions and arrangement of some of those build¬ ings which have come down to our time, it is difficult to determine whether all of them were destined 308 NOR ANGLO-NORMAN ARCHITECTURE. NOR for dwelling-houses, or were only halls for public occasions, or for the courts of the feudal lords. Of these buildings the invariable plan is a parallelogram of two stories; sometimes a double pa¬ rallelogram. The lower story was vaulted, as we have seen to have been the custom in Normandy, and it had no internal communication with the upper story. The upper story was approached by an exter¬ nal staircase, which probably was movable. The only fixed Norman staircase now extant is the one at Canterbury. The probability is that the lower story was occupied by the servants, and the upper story by the masters; but in none of the buildings of this time now extant do there exist any traces of subdivisions. An example of Norman Domestic architecture existed in Southwark till within these few years. It was the hostelry or town residence of the priors of Lewes. The church of St. Olave, Southwark, was confirm¬ ed to the prior and convent of Lewes by William, second Earl Warren and Surrey, the son of the founder. Earl William died in 1138. It appears, however, that the priors of Lewes rented a build¬ ing in 1170 and 1186, for their oc¬ cupation in London ; from whence it may be concluded, that the hos¬ telry in question was not built till after that period. The general features of the portion of the hos¬ telry which remained till lately nearly resembled those of the manor-house of Boothby Pagnel, Moyse’s Hall,at BurvSt. Edmund’s, and the building which is called the Pythagoras School at Cambridge. In 1826 was still existing at Barneck, in Northamptonshire, a Norman manor-house, which was not built for defence. In this in¬ stance the hall, which was the principal feature, was on the ground floor, and had no vaults underneath. The hall consisted of a centre and | two side aisles. The fine joints of the walls of this building denoted that it could not have been built much before the middle of the twelfth century. At Bury St. Edmund’s is a Nor¬ man domestic building, which goes by the name of Moyse’s Hall. At Boothby Pagnel, in Lincoln¬ shire, is a Norman manor-house on nearly the same plan. In this are a fire-place and a chimney, which indicates that the building of which it forms a part cannot be older than the second half of the twelfth cen¬ tury. This edifice has windows in the ends as well as the sides,—a circumstance which makes it evi¬ dent that to this building no others could have been attached. It is surrounded by a moat. At Christchurch, Hants,is a Nor¬ man remnant which has also a chimney. At Lincoln is a Norman domestic building which goes by the name of ‘ John of Gaunt’s Stables,’ but which, in fact, was the public meet¬ ing-house of a guild. It is so much enriched that it must be placed late in the reign of Henry II. These examples prove that about the middle of the twelfth century, mansions, distinct from castles for defence, began to be erected in England ; and that, independent of colleges, abbots’ lodgings, and the habitable parts of convents, in¬ stances existed of Domestic archi¬ tecture. But it was long before dwelling-houses acquired a charac¬ ter bearing any relation to the qua¬ lity of the proprietor, or were con¬ structed with much regard to con¬ venience. Examples of the Norman style of the time of Henry II. are to be seen in the abbey gateway, Bristol; in the Galilee, or chapel, at the west end of Durham,built byBishop Pudsey (1154 to 1197), together with the lateral portals of the nave; in the new nave and great west portal of Rochester, etc. 309 NOR ANGLO-NORMAN ARCHITECTURE. NOR It was in the latter years of the reign of Henry II. that the struggle between the Round and the Pointed styles, which is called the Transi¬ tion, began to take place in this country. Kirkstal abbey, in Yorkshire, was built in the thirty years preceding 1183. The nave arches are pointed, but the pillars are massive, and the windows and portals are round. The church at Roche abbey, though equally in the Transition style, and having round - headed windows above pointed arches, Norman mouldings and capitals, yet is of a less heavy character. Both build¬ ings, however, denote that during those years the new style was only just beginning to he received in England. About the same time (1170), Archbishop Roger employed the Pointed style in the new crypt of York minster. But the early examples of the Transition, of which the dates are known with the most undoubted certainty, are the round part of the Temple church, London, which was consecrated in 1185, and the choir of Canterbury cathedral, which was rebuilt after the lire in 1175, and in which the Pointed style was introduced by John of Sens, a French architect. Other instances are to be found in the great tower at the west end of Ely, built by Bishop Ridel, who died in 1189; in the county hall of Oke- ham, Rutlandshire; in the abbey church of Glastonbury, etc. But the nave of Rochester and the nave of Peterborough, rebuilt between 1170 and 1194, are proofs that the old fashion was not at once superseded by the new. Simultaneously with the intro¬ duction of the Transition style, hewn stone vaults appear to have been first thrown over the wider parts of English churches, which till then had been habitually roofed with wood. A stone vault was thrown over the new choir of Can¬ terbury, in 1174. It was customary before that time, to roof narrow spaces with plain cross-vaulting, hut not to vault wide spaces with stone. Plain cross-vaulting of rub¬ ble, with and without ribs, had been adopted before in crypts, side aisles, and chancels. Barrel-vault¬ ing, we have seen, was introduced in the time of William the Con¬ queror. From the time that the choir of Canterbury was built, which was not long after, it became com¬ mon to throw stone vaults over the naves of the larger churches of Normandy, and huge stone vaults, plain at first, and gradually en¬ riched, became habitual in Eng¬ land. Prominent buttresses and flying buttresses, as in Normandy, followed in the train of the stone roofs. From this time, the Round style fell gradually into disuse; but at Fountains abbey, the foundations of which were laid in 1204, and which was in progress during the forty subsequent years, the win¬ dows and portals are still round- headed ; and an instance of a round portal is to be found at Ketton, in Rutlandshire, as late as 1252. During the reign of Henry III. the Early Pointed style attained its most perfect condition. Fine ex¬ amples of this style are to be seen in the chapter-house, the transepts, and part of the choir of Westmin- ter abbey; in the choir of St. Al¬ ban’s ; in the nave of Lincoln ; the east end of Durham ; nave of Wor¬ cester, 1224; nave and spire of Lichfield; south transept of York ; and the older part of the choir of Southwell; and in Salisbury ca¬ thedral, which was begun in 1221, and carried forward, without inter¬ ruption, till it was completed. The establishment of the Pointed style was attended with one re¬ markable difference in England and Normandy. In Normandy, the semicircular chancel became, ge. 310 NUNNERY. NUN NOR nerally speaking, polygonal; in England, generally speaking, it be¬ came square. Polygonal chancels are as rare in England as square chancels are in the larger churches of Normandy; and this difference of shape in England afforded the opportunity of those magnificent east windows, which are so princi¬ pal and so splendid a feature of our cathedrals. Another difference to be remarked, is the battlement, which usually forms the parapet of English churches, and which never occurs in the ecclesiastical build¬ ings of France. It may be said,—1. That the supposed, existence of the Pointed style in Normandy, in 1056, is imaginary. 2. That the Normans, adopting the corrupt Roman style, gave it a character of their own. 3. That the Normans greatly con¬ tributed to the advancement of the arts in England. 4. That archi¬ tecture performed exactly the same revolution in England and France, France having, in all the changes, a certain precedence. Norroy, or North roy, in heraldry, one of the two provincial Kings at Arms, whose jurisdiction lies on the north side of the Trent, as does that of Clarencieux to the south. Northampton Tables , Tables made at the county town of Northampton, formed from the registers of burials of that locality, from which calcu¬ lations were made of the value of life, for the purpose of its insurance. (See article Assurance.) Nosing, the prominent edge of a moulding or drip; the projecting moulding on the edge of a step. Nosing of steps, the projecting parts of the tread-board or cover, which stand before the riser. The nosing of steps is generally rounded, so as to have a semicircular section ; and in good staircases a hollow is placed under them. Notch-board, a board notched or grooved out, to receive and sup¬ port the ends of the steps of a stair¬ case. Notching, the cutting of an excava¬ tion throughout the whole breadth of a substance : by this means tim¬ bers are fastened together, or their surfaces, when joined at angles, are made to coincide. Nozzles, those portions of a steam en¬ gine in which are placed the valves that open and close the communi¬ cation between the cylinder and the boiler and condenser, in low- pressure or condensing engines; and between the cylinder and boiler and atmosphere, in high-pressure or non-condensing engines. Nucleus, the internal part of the floor¬ ing of the ancients, consisting of a strong cement, over which was laid the pavement, which was bound with mortar. Nuisance, anything tending to hurt, to annoy, or to endanger health. (See the excellent work by Mr. Gibbons on this subject.) Nullah, in India, a natural canal, or small branch of a river. Nunnery, a Roman Catholic building for an association of nuns or females devoted to a life of religious seclu¬ sion. Previous to the Reformation, there existed in England 127 edi¬ fices for the convenient lodging of such pious women, 2 in Wales, and 20 in Scotland; in the whole in Great Britain, 149. But there were many convents and religious houses not specially named nun¬ neries, but which were receptacles also for such purposes. Nunnery, a term sometimes applied to the triforium or gallery between the aisles of a church and the clere¬ story ; so called from the situation of the nuns’ choir in some convents. At the present time, the roomy galleries over the aisles in West¬ minster abbey are called nunneries, probably from having been used by the nuns of Kilburne, when they visited the abbey, to which they were subordinate. Nut, a short internal screw, which 311 OAK OAK. acts in the thread of an external screw, and is employed to fasten anything that may come between Oak. There are two kinds of this timber common in England, on the Continent, and in America. Oak of good quality is more durable than any other wood which attains the same size: its colour is a well- known brown. Oak is a most va¬ luable wood for ship-building, car¬ pentry, frames, and works requiring great strength or exposed to the weather. It is also much used for carved ornaments, panelling of rooms, pulpits, stalls, and stand¬ ards for churches. It is likewise used in the construction of all kinds of buildings, for strength and sta¬ bility. English oak is one of the hardest of the species: it is consi¬ derably harder than the American, called white and red Canada oak. African oak is well adapted to the construction of merchant vessels. Italian oak is much purchased for our dockyards, to the prejudice of that which is proudly standing in our several forests. i Obelisk, in architecture, a quadran¬ gular pyramid : those of Egypt may be described as large stones, qua¬ drilateral, diminishing from the base upwards, till, within about a tenth of the height, the sides con¬ verge to a point. The width of the base is usually about a tenth of the height, to that part where the sides begin to converge: they are commonly formed from a single stone, mostly of granite. There are, however, two small obelisks in the British Museum, formed of basalt, and one at Philae, of sand¬ stone. When obelisks were first made in Egypt, it was customary with the patriarchs of the Jews to set up stones to perpetuate the memory of great events. Strabo calls such stones ‘books of history an epithet which might be applied with propriety to the inscribed OBL it and a flange on the bottom of the external screw or bolt. Egyptian obelisks. The date of the Flaminian obelisk, which is covered with hieroglyphics, is by some writers supposed to be be¬ tween 1580 and 1600 b.c. The first obelisk was raised by Rameses, King of Egypt, in the time of the Trojan war: it was 40 cubits high, and employed 20,000 men in build¬ ing. Phins, another king of Egypt, raisedone of 45 cubits, and Ptolemy Philadelphus another of 88 cubits, in memory of Arsinoe, etc. The Romans also erected many, which are well described in Roman history. Oblate, flattened or shortened; in geometry, a term applied to a sphe¬ roid, produced by the revolution of j a semi-ellipsis about its shorter j diameter. Of this figure is the , earth, and probably all the planets, having the equatorial diameter greater than the polar. Oblique, in geometry, aslant; not di¬ rect ; not perpendicular nor parallel. Oblique angle, one that is greater or less than a right angle. Oblique-angled triangle, one that has no right angle. Oblique arches, or Oblique bridges, are those w'hich conduct high-roads or railroads across a river, canal, etc., in an oblique direction : they are also called skew arches. Oblique line. When one straight line stands upon another, and makes unequal angles therewith, the an¬ gles are said to be oblique, the one being greater than a right angle, and the other less: hence a line is only oblique as it relates to another line ; otherwise the word would be destitute of meaning. Oblique sailing occurs when a ship, being in some intermediate rhomb between the four cardinal points, makes an oblique angle with the meridian, and continually changes both its latitude and longitude. 312 OBL OBSERVATORY. OGE Oblong, a rectangle of unequal dimen¬ sions ; in geometry, longer than broad. Observatory, a building erected for the purpose of making observations on the motions of the heavenly bodies. More particularly with re¬ ference to the study of Terrestrial Magnetism, observatories have been erected by the British Government in Canada, St. Helena, the Cape of Good Hope, and Van Diemen’s Land ; hv the East India Com¬ pany at Madras, Singapore. Simla, and Trevandrum ; and by the Rus¬ sian Government at St. Petersburg and other places, in connection with those at Gottingen, etc. The most munificent example of private de¬ votion to the science of Astronomy is the splendid observatory erected by Lord Rosse at Parsonstown, in Ireland. Obtunding, the blunting or taking away a sharp corner. Obtuse, in geometry, biunt; in oppo¬ sition to acute or sharp. Obtuse angle. In geometry, if the contained angle he less than a right angle, it is called an acute ; if greater, it is called an obtuse angle. Obtuse-angled triangle, a triangle which has an obtuse angle. Obtuse section of a cone, the hyper¬ bola of ancient geometricans, be¬ cause they considered it only such a cone whose section through the axis was an obtuse-angled triangle. Occus, the banqueting-room of a Ro¬ man house. There were several kinds of occi, viz. Corinthian, tetra- style, Cyzicene, and Egyptian. In the Greek houses the occi were spacious apartments, in which the mistress of the family employed herself and servants at the loom. Ochre, brown, a clay coloured brown by the oxide of iron. Ochre, red, a clay coloured red by the oxide of iron. Ochre, yellow, a clay coloured yellow by the oxide of iron. Octagon, a figure of eight sides and as many angles: when all the sides and all the angles are equal, the figure is called a regular octagon. Octahedron, in geometry, one of the five regular bodies, consisting of eight equal and equilateral triangles. Octostylos, a portico which has eight columns in front. Odeum, a small theatre for the re¬ citation of musical compositions, generally in the neighbourhood of the theatre : the odeum at Athens was contiguous to the theatre of Bacchus ; the odeum at Pompeii also joined the theatre. Odontoyraph, a very ingenious instru¬ ment, invented by Professor Willis, of Cambridge, to' enable the mill¬ wright, workman, and engineer to measure,draw, and design infinitely in extent, the teeth of wheels. Odyssey (In the) we have, for ex¬ ample, the case of Castor and Pollux, who enjoyed a peculiar privilege of life after death, and revisited earth in some mysterious manner on alternate days, and this too although they were buried. (Gladstone.) (Ecus, according to Vitruvius, apart¬ ments near or connected with the dining-room. (Eillets, or Oylets, small openings or loopholes, sometimes circular; ex¬ tensively used in the fortifications of the middle ages. Offices, as connected with the domes¬ tic purposes of large mansions palaces, etc., consist of kitchens sculleries, pantries, breweries, wash¬ houses, etc.; frequently detached or out-houses, and sometimes in cities, underground and vaulted palaces beneath the same roof. Offices, as connected with business, are apartments for the accommo¬ dation of clerks or accountants; merchants’ counting-houses, etc.; for law clerks, law agents, etc. Offing, in navigation, that part of the sea distanced from the shore where there is deep water, and no neces¬ sity for a pilot. Offset, or Set-off, the splay or narrow slanting course of stone or brick, 313 OGI OLIVER. ORB serving to connect two portions of a wall, the uppermost of which re¬ cedes from the face of that beneath. Ogee, a moulding consisting of two members, the one concave, the other convex ; the same with what is otherwise called cymatium. In Gothic architecture, ogees are very much employed. The term ogee is also applied to a pointed arch, the sides of which ate each formed of two contrasted curves. Ogives, arches or branches of a Gothic vault, which, instead of being cir¬ cular, pass diagonally from one angle to another, and form a cross with the other arches which make the sides of the squares, whereof the ogives are diagonals. The middle, when the ogives cut or cross each other, is called the key, sometimes carved in the form of a rose. The members or mouldings of the ogives are called nerves, branches, or veins; and the arches which separate the ogives, double arches. Oliver, a small lift-hammer, worked • by the foot. The hammer head is about 2-J inches squares and 10 inches long, with a swage tool having a conical crease attached to it, and a corresponding swage is fixed in a square cast-iron anvil- block, about 12 inches square and 6 deep, with one or two round holes for punching, etc. The ham¬ mer handle is about 2 to 2 } feet long, and mounted in a cross¬ spindle nearly as long, supported in a wooden frame between end- screws, to adjust the groove in the hammer face to that in the anvil- block. A short arm, 5 or 6 inches long, is attached to the right end of the hammer axis ; and from this arm proceeds a rod to a spring- pole overhead, and also a chain to a treadle a little above the floor of the smithy. Olympiad, a period of four years, by which the Greeks reckoned their time. The first Olympiad corre¬ sponds with the 775th year before the birth of our Saviour, and 22 years before the building of Rome. Oolite, the Portland stone used in ar¬ chitecture, called also freestone and roestone. Opa, according to Vitruvius, a bed or cavity in which the head of a tie- beam rests. Opaque, cloudy, not transparent. Ophites, a black marble. Opie (John) was born in Cornwall, 1761, and died April, 1807. Horne Tooke and Sir James Mackintosh speak very highly of his intellectual powers. He sketched out a plan of weekly study, from which plea¬ sure or persuasion seldom wiled him. Opisthodomos, the enclosed space be¬ hind a temple: the treasury at Athens was so called, because it stood behind the temple of Mi¬ nerva. Oppidum, according to the Romans, a mass of buildings : an entrance to a town ; the fafade to a public building, not unlike to the termini on the principal lines of railway. Opposite angles, those which are formed by two straight lines cross¬ ing each other, but not two adja¬ cent angles. Opposite cones are those to which a straight line can be everywhere applied on the surface of both cones. Opposite sections, those made by a plane cutting two opposite cones. Optics, the science of direct vision, including catoptrics, dioptrics, and perspective. Optostrotum, according to the Greek, a brick-paved flooring. Opus, Roman reticulated masonry: a mode of workmanship. Or, in heraldry, gold: it is denoted in engraving by small points all over the field or hearing. Ora, a Roman hawser. Oratory, a small private chapel or closet for devotion. Orb, a mediaeval term for a blind window. Orbs, in Gothic ornament, bosses and 314 ORDNANCE SURVEY. ORB knots of foliage, flowers, or other ornament in cornices. Orbiculus, according to Vitruvius, a roller or a pulley revolving upon an axis, and having a groove in its circumference for the rope to tit into; employed as a mechanical power for raising or drawing. Orchestra, the area in the Greek theatre comprised between the lower range of seats and the pro¬ scenium. In the Roman theatre, the orchestra was appropriated to the senators; but in the theatres of the Greeks it was the scene of action of the dancers. Orders of Architecture, usually named the ‘ five orders,’ without reference to other styles of architecture, are thus enumerated by most writers : —1. Tuscan. 2. Doric. 3. Ionic. 4. Corinthian. 5. Composite. (For their proportions, see Architec¬ ture.) Ordinates, in geometry and conics, lines drawn from any point of the circumference of an ellipse, or other conic section, perpendicularly across the axis, to the other side. Ordnance Survey of Great Britain and Ireland: a work of great import¬ ance in ascertaining the true geo¬ graphical position of our islands and of their varied superficial fea¬ tures. This survey originated in the mutual desire on the part of English and French philosophers to determine the precise difference of longitude between the meridi¬ ans of the Greenwich and Paris observatories. In the pursuit of this object, a meeting was arranged at Dover between three members of the French Academy, MM. Cas¬ sini, Mechain, and Legendre, and General Roy and Dr. Blagden, to arrange plans of operation. In the course of the subsequent survey, the officers of the Royal Artillery, to whom the superintendence of the work was entrusted, extended their views and operations, and, under the patronage and at the expense of the Board of Ordnance, ORD proceeded to determine the length of as many degrees on the meridian as came within the limits of the survey. The rules bv which the main lines for this and all other extended surveys are obtained, are derived from the princiffies of trigonometry, or the properties of triangles. By these principles we are enabled to compute the exact form and dimensions of any triangle from the actual measurement of one side only, and of the angles formed at its extremities by the other sides. Upon these principles the true figure and size of our globe have been determined upon the relative lengths of degrees of a meridian in different latitudes. The exactness of the results of these operations depending upon the correct measurement of the one side, or base-line, and of the angles at its ends, formed by the two imaginary sides which have a common meeting point in some distant and conspicuous object, the apparatus for measuring this side and the angle is required to act with extreme delicacy and exact¬ ness. For measuring the length, rods of various materials have been used, and endeavours made to obviate the effect of changes of temperature in altering the length of the rods themselves. General Roy commenced the measurement of a base line on Hounslow Heath with rods of deal, each twenty feet long. But these rods, although prepared in the most careful man¬ ner, of the best seasoned timber, perfectly straight, and effectually secured against bending, were found to suffer such changes of length, from the varying dryness and moisture of the air, as ren¬ dered them utterly unfit for the purpose, and glass tubes were eventually substituted, each of them twenty feet long, and en¬ closed in a frame of wood, allow¬ ing only expansion or contraction in length from heat or cold ac- 315 ORGAN. ORG ORD cording to a law ascertained by experiments. With these rods a base of about 5-£ miles in length was measured so exactly, that a remeasurement by Colonel Mudge several years afterwards, made with a steel chain constructed by the celebrated Ramsden, differed only from the original line to the extent of 2| in. Steel chains are jointed similar to a watch-chain, and are always used with uniform tension, the differences in length due to temperature being calculated upon the observed fact, that each degree of heat above 62 Fahr. extends the chain '0076 of an inch. For determining the angles, the English officers used an excellent theodolite by Ramsden, having both an altitude and an azimuth circle, and a telescope of great power. This instrument, com¬ bining the powers of a theodolite, a quadrant, and a transit instru¬ ment, is capable of measuring hori¬ zontal angles to fractions of a second. It is recorded among the proofs of the accuracy attained in this triangulation, that a testing line, or base of verification , as termed in geodesic operations, measured on Salisbury Plain, of which the length exceeded seven ndles, differed only one inch from the computation carried through the series of triangles from Houns¬ low Heath to Salisbury Plain. When the primary triangulation had been thus carefully completed, a further subdivision of each of these great triangles was perform¬ ed, and each of these again was subdivided into others, so that the entire plot of the country was re¬ presented by a complete network of triangles. Each of these divi¬ sions and subdivisions being form¬ ed independently of the others, and yet the exact accordance of the whole being insisted on and effected, accuracy is secured in all these principal operations, and the filling in of each of these spaces is entrusted to a different class of operators, whose labours in pro¬ ducing the final plan are so divided and arranged that the work of each is a check upon the exactness of his predecessor. Thus the sur¬ veyors measure the lines and angles on the ground, but another class of assistants (the plotters) produce the plan from the records of the surveyors, and a third class (ex¬ aminers) test the plan thus pro¬ duced by subsequent comparison in the field. One effect of this system, by which-the range of ope¬ rations confided to each operator is thus limited, and the fidelity of these thus severely scrutinized, is, that the bulk of the work after the triangulation may be safely confided to an inferior and cheaply engaged class of assistants, and great comparative economy thus attained. The Ordnance Survey of Great Britain and Ireland is plotted to different scales. Organ. This word is derived from the Greek organon: organum in Latin, organo in Italian, orgue in French, orgel in German. It signi¬ fies, generally, an instrument; but is now used for the name of the grandest and most worthy of mu¬ sical instruments. The tones of an organ are pro¬ duced from the pipes only; of these some are of wood, others of various kinds of metal, and even of glass. An organ of full compass may contain all the sounds recog¬ nized in the science of music, from the lowest appreciable to the very highest. The largest pipes pro¬ duce the lowest sounds, and some few are made as long as about 32 feet, while the smallest are about the size of the pipe of a very small key. Organs are of various kinds, viz. for the church, the concert- room, and for the private drawing¬ room. The church organ should be of a full, deep, and solemn cha¬ racter ; while the concert-room I 7 316 ORGAN. ORG organ should be of a lighter and more brilliant kind, with every va¬ riety of stop, in order to imitate, not only the full orchestra, but also certain ‘solo’ instruments. Hence we have the flute-stop; the haut¬ boy, the cremona or krum-horn, the vox-humana, etc. stops; ac¬ cording to the extent of the instru¬ ment. These solo, or fancy stops, belong only to the concert-room or drawing-room organ, and are wholly unbecoming in one for the church. We have not space to give any¬ thing like a description of this the noblest of instruments ; and it must suffice to say that it con¬ sists of bellows which supply the pipes with wind by means of a wind-chest; the wind being con¬ veyed therefrom, through channels, under the different ranks, or rows of pipes, and thence into the pipes by means of pallets, or valves, opened at the pleasure of the per¬ former, by pressing the proper lever or key. The organ is a very ancient in¬ strument of the church, and must have been very unwieldy, since we are told of one in the cathedral church at Halherstadt, which had only a few large pipes, and the keys were more than a hand- breadth in width, and were beaten or pressed down by the fist, or elbow; the wind being supplied by several small bellows. We are also told of the Winchester organ, which required seventy men to supply it with wind ; its compass was of ten notes only, although it had 400 pipes, i. e. forty to each note; it was so loud that it could be heard all over the city. The organ is usually described as being of three kinds,—the great, or full chorus organ, the swell organ, and the choir organ : the latter is used to accompany the softer parts of the music, and is such an instrument as was carried in the ancient pro¬ cessions, in the rogation days, and ORG other seasons, to accompany the priests with while chanting the litanies; the performer, or,‘more properly speaking, the minister at the organ, being carried also with the instrument, and seated : hence this organ was called the chair- organ, now corrupted into choir- organ, from the difference in its employment. The swell organ is used chiefly to accompany solos ; for interludes, and such like fanci¬ ful music, and takes its name from being able to swell out its sounds by openings made by turning a series of boards on their centres, similar to a Venetian blind, these boards being connected by levers under the control of the per¬ former’s foot. The key-board, or row of keys of an organ, are like those of a pianoforte, only they require to be pressed down (not struck like those of the latter instrument), so as to open the pallets before mentioned, and cause the pipes to speak. A complete church organ contains three rows of keys, one for each of the above-mentioned organs; and most organs have also a row' of keys called pedals, to enable the organist to play the bass-notes with his feet. In organs that are played by means of a wind, or handle, the part of the organist is performed by a cylinder, on w'hich are placed a number of wires so contrived as to press upon the levers, and open the pallets or valves; and hence those instruments are called barrel organs. They are of little or no use for the purposes of the church. It has been the fashion, for some time, to make one organ do the work of two, namely, the full organ and the choir organ: but it is at best but a sorry con¬ trivance ; for in such an organ there can be no good choir organ mixture; and the full organ is ge¬ nerally too noisy, the fullness being made up of loud-voiced pipes, in- 317 ORG OSCILLATING ENGINE. OXI stead of their being round, mellow, and full-toned. These kinds of organs have not the dignified and solemn character necessary for real church music. Organ screen, an ornamental stone wall or piece of timber framework, on which a church organ is placed, and which in English cathedrals and churches forms usually the western termination of the choir. Organum, a name given to a machine or contrivance in aid of the exercise of human labour in architecture and other arts. Oriel window, a projecting angular window, mostly of a triagonal or pentagonal form, and divided by mullions and transoms into differ¬ ent bays and other proportions. The oriel has been discussed by many writers, but there cannot be conceived an architectural charm more cheerful to the interior, or more decorative to the exterior of a building, than an oriel window. Orlop, in shipping, the middle deck. Ornithon, an aviary or poultry-house, or the appurtenance to a farm villa. Orrery, in mechanics, a machine which by many complicated move¬ ments represents the revolutions of the heavenly bodies. Orthography, in architecture, the ele¬ vation of a building, showing all the parts thereof in their true pro¬ portions : the orthography is either external or internal. The external is the delineation of the outer face or front of a building; the internal is a section of the same. Oscillating Engine, a marine engine, with a vibrating cylinder, having the piston rod connected to the crank, and the cylinder supported by the trunnions projecting from the sides at or near the centre, cast hollow, and connected to the steam and eduction pipes. Oscillation, or vibration, in mechanics, the act of moving backward and forward like a pendulum. Oscillation, the axis of, in mechanics, a right line parallel to the apparent horizontal one, and passing through the centre, about which the pen¬ dulum oscillates. Osterly House. “ The opulence and gallantry of Sir Thomas Gresham rivalled the wonders of romance. Queen Elizabeth had visited that superb mansion, and on quitting the window to seek her bed, had remarked aloud, ‘ How much more gracefully the court-yard would appear if divided in two by a wall.’ The words were caught up by Sir Thomas, who instantly, on quitting the royal presence, sent hastily to his masons and bricklayers, assisted them with innumerable labourers, worked all the night, and completed the wall according to the Queen’s wishes before she had risen from her bed. The courtiers were cha¬ grined at the knight’s abruptness, and one of them consoled himself with a conceit, ‘ that it was no way strange that one who could build a ’change could change a build¬ ing.’ ” Ostium, an inner door, the door of a chamber. Outward angle, the same as a salient angle. Ova, in architecture, ornaments in the form of eggs, carved on the contour of the ovolo, or quarter- round, and separated from each other by anchors and arrow-heads. Oval, a figure in geometry, bounded by a curve-line returning to itself. Overshot-wheel, a wheel driven by the weight of water conveyed into buckets, disposed on its circumfer¬ ence so that one part of the wheel is loaded with water while the other is empty. Over story, the clear story or upper story of a building. Ovolo, a convex moulding, mostly used in classical architecture; in the Roman examples it is an exact quarter of a circle; in Grecian it is more flat and quirked at the top. It is frequently used in the deco¬ rated Gothic style. Oxidation, rusting; the process of 318 PAINTING. OXY converting metals and other sub¬ stances into oxides, by combining a certain portion of oxygen with them. Oxygen, in chemistry, a gaseous ele- Pack, a quantity of material, either wood or coals, placed or piled up to support roofs, or for other pur¬ poses. Paddle-shaft, the shaft upon which the paddle-wheel is fixed, placed centrally with, and connected to, the crank-shaft. Paddle-wheel, the wheel fixed upon the paddle-shaft, for propelling a vessel through the water by the action of a number of paddle- boards fixed at the circumference. Pagoda, in architecture, a name ap¬ plied by the Europeans to Hindoo temples and places of worship, but not by the Hindoos themselves, who have no such appellation ; they are square stone buildings, not very lofty, crowned with a cupola: the pagodas of China are, however, lofty houses, which sometimes rise to the height of nine stories, of more than twenty feet each. The buildings are depositories of their idols, and used for their worship. Painted and Stained Glass, formerly used exclusively for ecclesiastical purposes, — displaying devotion and spiritual bearing. Latterly painted and stained glass have been used for domestic purposes. The art of painting on glass was known as early as the sixth century, and was applied to the enrichment of the basilica of St. Sophia, and other churches in Constantinople; and in the reign of Charlemagne some progress was made in enrich¬ ing and beautifying glass with colours. In the tenth century it was much admired, and advanced rapidly : Henry II. patronized this art. In France it progressed in all the magnificence of colour and exe¬ cution, and was extensively diffused PAI ment of great importance in the economy of Nature: it is essen¬ tial to the maintenance of organic life : hence its original name, ‘ vital air.’ in England. In Canterbury and York some beautiful examples re¬ main, for the admiration and ex¬ ample of modern practice. Of the cinque-cento style, the revival of art under the immortal Albert Dtirer, some very fine specimens of the period, picturesquely drawn, are to be found in fine preservation in St. Jacques, at Liege ; and of ra¬ ther a later time, those of the Crabeths, at Gouda, in Holland, are magnificent executions of this art by these brothers. One of these windows, upwards of 70 feet high, was executed by Theodore Crabeth, by command and at the expense of Queen Mary of England, consort of Philip II.: a portion of the picture is magnificently painted, the sub¬ ject of which is the Queen, with her husband, kneeling at the Lord’s table. The upper part of this win¬ dow has been destroyed by a storm, but the subject referred to remains perfect, and exhibits correct like¬ nesses of these sovereigns. Painting. The art of painting gives the most direct and expressive re¬ presentation of objects ; and it was doubtless for this reason employed by many nations, before the art of writing was invented, to commu¬ nicate their thoughts, and to con¬ vey intelligence to distant places. The pencil may be said to write a universal language,forevery one can instantly understand the meaning of a painter, provided he be faithful to the rules of his art: his skill enables him to display the various scenes of nature at one view, and by his delineations of the striking effects of passion, he instantaneously af¬ fects the soul of the spectator. In¬ vention in painting consists prin- 319 PANEL. PAI cipally in three things: first, the choice of a subject properly within the scope of the art; secondly, the seizure of the most striking and energetic moment of time for re¬ presentation ; and, lastly, the dis¬ covery and selection of such objects, and such probable incidental cir¬ cumstances, as, combined together, may best tend to develope the story or augment the interest of the piece. Architects will often find deco¬ rations of a room and its furniture well worthy of their study. In houses recently built, both in town and country, the taste of the archi¬ tect has been called in, to give designs for the arrangement of curtains, for grates, pier tables, chairs, and sofas; and in many in¬ stances the superior chasteness of the designs, and the harmony of the whole with the architectural style of the rooms, may be seen, conformable with the different uses to which the rooms are appro- priated. Painter, in navigation, a sea term for a rope employed to fasten a boat to the ship, wharf, etc. Palaestra , a building appropriated to gymnastic sports. Palaces of Persia (the royal country) are at this day castellated, and many villages have towers of de¬ fence. Pale, in heraldry, the third and middle part of the escutcheon. Palisander, a name used on the con¬ tinent for rose-wood. Pall, in heraldry, denotes a sort of cross, representing the pallium or archiepiscopal ornament sent from Rome to metropolitans. Palls, in ship-building, strong short pieces of iron or wood, placed near the capstan or windlass', so as to prevent their recoiling. Palladium, a metal found with pla- tina, but in small quantity. Palladium, in antiquity, a wooden image of the goddess Minerva or Pallas, the possession of which in¬ volved the fate of Troy. PAN Pallium or Pall, in church rituals, a pontifical ornament worn by popes, patriarchs, primates, and metropo¬ litans of the Roman church, in the form of a fillet of black silk, over the shoulders, with four red crosses. Palm-trees , wood of great variety, imported from the East and West Indies, but sparingly employed in England for cabinet and marquetry work, and sometimes for billiard- cues, etc. Palette (French), in painting, a light board on which the colours are held. Palsgrave, in heraldry, a count or earl, who has the overseeing of a palace. Pandation, in architecture, a yield¬ ing or bending in the middle. Pane, the light of a window’; for¬ merly applied also to the sides of a tower, turret, spire, etc. Panel, in carpentry, etc., a square piece of any matter inserted be¬ tween other bodies ; sunken com¬ partments of wainscoting, ceilings, etc., principally employed in Gothic and Domestic architecture for in¬ terior fittings. Panel, a space or compartment in a wall, generally of English or Flemish oak, and on a ceiling, en¬ closed within a raised margin. Panel, in mining, a heap of ore dressed and ready for sale. Panemore, in mechanics, a globular windmill, proposed to be erected in the centre of a ship, for turning wheels and paddles. Panoply, in heraldry, complete ar¬ mour. Panorama (Full view), in painting, a picture drawn on the interior sur¬ face of a large cylinder, represent¬ ing the objects that can be seen from one station when the observer directs his eye successively to every point of the horizon. Pantheon, a temple dedicated to all the gods; one of the most cele¬ brated edifices of Rome. Pantograph, in mechanics, an instru¬ ment contrived for the purpose of 320 PARABOLA. PAR copying drawings, so that the copy may be either similar to or larger or smaller than the original. (See Pentagraph.) Para, in Cornish mining, a gang or party of men. Parabola, one of the conic sections formed by the intersection of a plane and a cone when the plane passes parallel to the side of the cone. Parabolic Pyramidoid, a solid gene¬ rated by supposing all the squares of the ordinates applicable to the parabola so placed that the axis shall pass through all their centres at right angles, in which case the aggregate of the planes will form the solid called the parabolic pyra¬ midoid, the solidity of which is equal to the product of the bases and half the altitude. Paraboloid or Parabolic Conoid, the solid generated by the rotation of parabola about its axis, which re¬ mains fixed. A frustum of a pa¬ raboloid is the lower solid formed by a plane passing parallel to the base of a paraboloid. Parabolic spindle, the solid gene¬ rated by the rotation of a parabolae about any double ordinate. Paradise, a private apartment, a study, the private appurtenances to a convent. Paradromides, hypaethral walks, at¬ tached to the Greek palaestra. The Romans called these walls xysta; whereas the xysta of the Greeks were covered porticoes, in which the athletae exercised in winter. Parallel, in geometry, is applied to lines, figures, and bodies which are everywhere equidistant from each other, or which, if ever so far pro¬ duced, would never meet. Parallel bars, the rods parallel to the centre line of a beam, joining the connecting links at the lower ends. Parallel motion, the connection be¬ tween the top of the piston-rod and the beams : a name given to a con¬ trivance, invented by James Watt, for converting a reciprocating cir- PAR cular motion into an alternating rectilinear motion. Parallel ruler, an instrument consist¬ ing of two wooden, brass, or steel, rulers, equally broad throughout, and so joined together by the cross blades as to open to different inter¬ vals, and accede and recede, yet still retaining their parallelism. Parallelogram, in geometry, a qua¬ drilateral right-lined figure whose opposite sides are parallel. Parallelogram of forces is a phrase denoting the composition of forces, or the finding a single force that shall be equivalent to two or more given forces when acting in given directions. Parallelopiped, in geometry, a regular solid, contained under six parallelo¬ grams, the opposite of which are equal and parallel; or it is a prism whose base is a parallelogram : it is always triple to a pyramid of the same base and height. Parament, the furniture, ornaments, and hangings of an apartment for a room of state. Parameter, a constant right line in each of the three conic sections, and otherwise called latus rectum, be¬ cause it measures the conjugate axes by the same ratio which has taken place between the axes them¬ selves, being always a third pro¬ portion of them. Parapet, the upper part of a house, which is above the springing of a roof, and guards the gutter; the upper part of a wall, a bridge, a terrace, or balcony, etc. Parapets around the flat roofs of houses in the East are of most ancient date. “ When thou buildest a new house, thou shalt make a battlement for thy roof, that thou bring not blood upon thine house, if any man fall from thence.”— Beut. xxii. 8. Parascenium, in ancient theatres, a place behind the scenes to which the actors withdrew to dress and undress themselves. Parastalce, square columns, or antae ; called also parastacles and parasta- 321 PASTICI. PAR PAT ! licae. Vitruvius uses the term to signify the square posts placed be¬ hind the columns of the basilica, for the support of the floors of the upper porticoes. Pargeting, parge-work. plaster-work, employed exteriorly for timber houses, as an ornament; used also in plain‘and ornamental work, for both the exterior and interior. Paries, the waljs of a Grecian house, in contradistinction to the wall of a city ; a small enclosure, such as a ! court-yard. Parlour , a private apartment in a 1 dwelling, usually on the ground floor ; a speaking-room in a con¬ vent. In the time of Henry VIII. parlours and privy rooms—summer parlours, winter parlours—were well, comfortably, and conveniently furnished ; a proof that the gentry of that period were not quite so far behind the preseut race as might be supposed. Parsonage-house, a residence of the incumbent of a parish, a building in the vicinity of a church. Patera, a round dish, plate, saucer, or goblet. Patina, a basin or bowl of earthen¬ ware, rarely of bronze. Parthenon, in architecture, the tem¬ ple of Minerva at Athens. Particle, the minute part of a body, or an assemblage of several atoms of which natural bodies are com¬ posed. Partners, in naval architecture, are thick pieces fitted into a rabbet in the mast carlings, to receive the wedges of the mast; likewise tem¬ porary pieces nailed on the deck round the pumps. Partridge wood is the produce of the Brazils and the West India Islands : it is sent in large planks, or in round and square logs. It was formerly employed iii the Brazils for ship-building, and is known in dockyards as cabbage-wood. Party walls are partitions of brick made between buildings in sepa¬ rate occupations, for preventing the spread of fire. These are made thicker than the external walls ; and their thickness, and the neces¬ sity of their use, are regulated by Act of Parliament, and specified in some of the clauses of the Buildings Act passed in the reign of the present Queen. Parvise, a porch : an open area be¬ fore the entrance of a church. Paschal, a stand or candlestick, of a large size, used in Roman Catholic worship. Pasigraphy, the art of universal writ¬ ing. Passant, in heraldry, a term applied to an animal in a shield appearing to walk leisurely : for most beasts, except lions, the word tripping is frequently used instead of passant. Passion, in painting, implies an emo¬ tion of the body, attended with certain expressive lines in the face, denoting an agitation of soul. Pastici, or Imitations in Paintings. Teniers understood the union of colours extremely well, yet Bassan was superior to him in the sweet¬ ness and vigour of his tints. De Pile recommends it to all persons who would not wish to be deceived by pastici, to compare the taste of design, the colouring and the cha¬ racter of the pencil, with the ori¬ ginals. Teniers, Giordano, and Bon Boulloque are those who have appeared with the greatest repu¬ tation for imitating other great masters ; and, beside these, many other artists have employed them¬ selves in painting pastici. Pastoral staff, the official staff of an archbishop, a bishop, or mitred abbot. Patand, the bottom plate or sill of a partition of a screen. Paten, a small plate or salver used in the celebration of the eucharist. Patents for Inventions are publie grants to the inventors of new and useful machinery and processes in the arts, and by which cer¬ tain privileges are secured to the inventors, for the exclusive use 322 pat patents for inventions. pat and exercise of their inventions during a limited period. Patents are therefore monopolies of a de¬ finite character; but being de¬ signed as a security for the reward of those whose ingenious faculties and practical skill have produced improvements of general utility and value, these monopolies, if justly granted and honestly exercised, are not to be decried as injurious to the public interests, but should be conceded with willingness, and command the liberal protection of the community, which is destined to reap a continual and permanent advantage from the improvements thus fostered in their infant de¬ velopment. Patents for inventions should therefore be admitted as bar¬ gains between the inventor on the one hand, and the public on the other; and the abuses to which these bargains are liable arise from the common causes of officialcorruption and individual cupidity and jealousy. The laws under which patents are granted vary in their form in the several European and American States, and are all, in some degree, imperfect, and ineffective of their proper object. In the United Kingdom of Great Britain and Ireland patents are granted to the inventor or im¬ porter from abroad of “ any man¬ ner of new manufacture,” one grant covering the whole realm with the Channel Islands and the Isle of Man. The colonies were formerly included in the grant for England when applied for, on pay¬ ment of extra fees ; but this prac¬ tice has been discontinued. Pa¬ tents are granted in the colony of Victoria, and a law has recently been enacted in India for the same purpose. It is also probable that the patent system will become gradually extended to the colonies generally, in a more definite and practical form than it could be when the grant was merely tacked on to the English patent. British patents are granted as matters of course, provided certain legal forms are duly complied with, certain stamp duties paid, and the legal advisers of the Crown (the attorney or solicitor-general) are not required by opposing parties to ascertain whether the privilege sought will interfere with any con¬ temporaneous application, or with any existing patent. But the va¬ lidity of the patent is entirely at the patentee’s own risk. The process of soliciting a patent is as follows :—The applicant has to petition the Crown to grant Letters Patent for the invention, and he accompanies his petition with a declaration of the grounds of his request, and a specification either provisional or final, by which the invention sought to be protected may be identified. The difference between a provisional and a final specification is, that in the former kind of document the details are reserved: while in the latter they are expressed. Every provisional specification is submitted to the law officer, who on being satisfied of its sufficiency, allows a certifi¬ cate of provisional protection to be issued. The provisional protection lasts nominally six months, but really only four months ; because the patent will not be granted un¬ less notice to proceed be given within four months from the date of the original record of the appli¬ cation. The notice to proceed is inserted in the ‘ London Gazette,’ and the public are at liberty, with¬ in a period of twenty-one days from the date of the insertion, to enter notice of objections to the granting of the patent. The case is then referred to the law officer, with whom rests the decision between the parties. Should there be no opposition, the patent is granted. Having obtained the Great Seal, the patentee is allowed a period of six months from the original de¬ posit of his papers, to prepare and 323 PAT PATENTS FOR INVENTIONS. PAT file his complete or final specifica¬ tion (unless he deposited it at first, which is rarely advisable), with the drawings required to illustrate the invention and to give an accurate idea of the mechanism employed. For this purpose great care and judgment are needed, based on a knowledge of former patents, to frame the specification so that it shall explain with sufficient clear¬ ness the precise nature of the im¬ provements, and have that value as property which a good specifica¬ tion of a patent always has. The patent is now complete, and the patentee can safely proceed to practise under it. The patentee is enabled, under the authority of the attorney or solicitor-general, to amend his title and specification in case of need, and to disclaim part or parts of his claims, which he may have since found to be untenable. He may also petition for a prolongation of his term, of fourteen years, which petition is referred to the Judicial Committee of the Privy Council, who grant the same if the petitioner make out a case, satisfactory to them, of extraordinary losses, de¬ lays, or other special reasons for the prolongation. The property in a patent can be defended from infringement by a bill in equity, or by an action at law. It has been recently found, however, that the ordinary courts of law and equity are incapable of dealing satisfactorily with the sci¬ ence which forms the chief part of the inquiry in a patent case. A special tribunal, to interpret the specification with authority in the first instance, has therefore become a necessity. The patent may be assigned in whole or part by the patentee to any number of persons: it may also be mortgaged, and licenses may be granted for the use of the patent in a variety of modes. But all assignments and licenses must he registered at the Great Seal Patent Office, in order to give a title to the parties interested. The cost of obtaining a patent, including fees for agency, if unop¬ posed, is £30. But the patent expires at the end of three years, unless a further stamp-duty of £50 be paid; and at the end of seven years, unless a still further stamp duty of £100 be paid. To these items should be also added the cost of preparing and copying spe¬ cification and drawings, the charges for which are, of course, very vari¬ able, according to length, intri¬ cacy, etc. The expenses and regulations under which the foreign patents are granted vary considerably. The following brief epitome must suffice in this place. In the United States of America, patents are granted only to the absolute inventor, always for four¬ teen years, and are granted or withheld at the option of the Go¬ vernment Commissioners of Pa¬ tents. The amount of official fees payable depends upon the country of which the applicant is a native. Thus, a citizen of the United States, or a foreigner who has re¬ sided in the States one year next preceding the application, and has made oath of his intention to be¬ come a citizen, pays a fee of =8*30; I a subject of the Sovereign of Great Britain, *8*500 ; and any other foreigner, =8*300. If the applica¬ tion for a patent be rejected by the Commissioner, two-thirds of the fees paid are returnable. In France, patents for inventions are granted alike to natives and foreigners, and the duration of the privilege may be fixed by the pa¬ tentee at five, ten, or fifteen years, the amount of tax being propor¬ tional to the term, namely, 500 francs for five years ; 1000 francs for ten years; and 1500 francs for fifteen years; payable by annual instalments of 100 francs. The 324 PATENT YELLOW. PAT patentee thus enjoys the power of relinquishing his invention, if found unprofitable, at any time during the intended term, by ceasing to pay the annual instalment of fees. In Belgium, patents are granted for five or ten years : imported in¬ ventions are patentable, and the Government tax, which is not heavy, is paid annually in small instalments, increasing by 10 francs each year. In Holland, patents are granted for five, ten, or fifteen years, and may he had for foreign as well as native inventions. The fees for a patent for five years are 150 guilders, or £12. 10,s. ; and for terms of ten or fifteen years they vary from 300 to 750 guilders, or from £25 to £62. 10s. In Prussia, Russia, etc., the Go¬ vernments exercise a discretionary power in granting or refusing pa¬ tents, and the laws are of a strin¬ gent and arbitrary character. In Austria, patents are granted for terms from five to fifteen years ; the taxes must be paid when the application is made, and the in¬ vention put in practice within one year from the date of the grant. The German and Italian States have patent laws peculiar to them¬ selves, but generally similar to those already described. Patent yellow, Turner's yellow, or Montpellier yellow, is a submuriate or chloride of lead, which metal is the basis of the most opaque yellow pigment: it is a hard, pon¬ derous, sparkling substance of a crystalline texture and bright yel¬ low colour, hardly inferior, when ground, to chromic yellow. It has an excellent body, and works well in oil or water, but is soon injured, both by the sun’s light and impure air; it is therefore little used, ex¬ cept for the common purposes of house-painting, etc. Patera, a circular flat ornament, used in Classical architecture; used also in Gothic and Italian architecture. PEA Patriarchs, the. The chief employ¬ ment of the patriarchs was the care of their cattle, viz. goats, sheep, camels, horned cattle, and asses. There were no horses nor swine among them. Theirs was a pastoral life, and not a life of tillage. They were always in the field, lying under tents, shifting their abode according to the convenience of pasture. Paul, the catch which holds a ratchet- wheel,'allowing it to turn in one direction only. Pavilion, in architecture, a detached building; an insulated turret, con¬ tained under a single roof, some¬ times square and sometimes dome- formed ; named from its resem¬ blance to the roof of a tent. The late palatial monstrosity at Brighton was called a pavilion. Pax, a small tablet, having on it a representation of the crucifixion, or some other Christian symbol, of¬ fered to the congregation in the Romish church, to be kissed in the celebration of the mass : it was usually of silver, or other metal, with a handle at the back, but was occasionally of other materials ; sometimes it was enamelled, and set with precious stones. Peach-stone, a bluish-green soft stone. Pearl-white. There are two pigments of this denomination : one, falsely so called, prepared from bismuth, which turns black in sulphuretted hydrogen gas or any impure air, is employed as a cosmetic : the other is prepared from the waste of pearls and mother-of-pearl, is exquisitely white and of good body in water, but of little force in oil or varnisb ; it combines, however, with all other colours, without in¬ juring the most delicate, and is it¬ self perfectly permanent and in¬ noxious. Pear-tree, a native European wood ; its colour is a light brown, some¬ thing of a pale-mahogany or cedar: it is employed by the Tunbridge turners. 325 PEA PEDIMENT. PEE Pea-stone, or pisolite, in mineralogy, pisiform limestone. Peat, in mineralogy, a substance con¬ sisting of the twigs, leaves, and roots of trees, mixed with grass, straw, plants, and weeds, that have lain long in water, and become con¬ verted into a blackish-brown mass that may be cut with a spade, and dried for fuel. Pedestal, in architecture, the lower member of a pillar, named by the Greeks stylobates and stereobates ; also the basis of a statue. In Classical architecture it consists of three divisions: the base, or foot, next the ground, the dado, form¬ ing the main body, and the cor¬ nice, or sur-base moulding, at the top. Pediment, the triangular plane or sur¬ face formed by the vertical ter¬ mination of a roof consisting of two sloping sides ; consequently it so far corresponds with the gable, but in other respects differs widely from it. One material difference be¬ tween them is, that whereas the gable has no cornices, the pediment is bounded by three, viz. a horizon¬ tal one, beneath it, forming its base, and two sloping or raking ones, as they are technically termed; and the triangular space or surface in¬ cluded within them is distinguished by the name of the tympanum of the pediment. Another marked differ¬ ence between them is, that the gable may be of any pitch; and being merely a continuation of the wall below, instead of being, like the pediment, separated from it by any horizontal mouldings, its pro¬ portions do not at all depend upon the height or width of the front or compartment of the front which it terminates, but may be an equila¬ teral triangle^ or even considerably more, as to height, and, besides, is in nowise governed by the height of what is beneath it. The pedi¬ ment, on the contrary, must be pro¬ portioned to the height of the order which it crowns; consequently its pitch must be decreased in some¬ what the same ratio as its length or base is increased, or, in other words, the greater the number of columns beneath a pediment, the lower must the pitch of the latter be. Hence it is hardly possible to place more than eight, or, at the utmost, ten columns beneath a pe¬ diment, without making the pedi¬ ment either too low in itself, or else too lofty and heavy a mass in com¬ parison with the columns beneath it; thereby not only overloading them—the columns being propor¬ tioned to their entablature alone— but also diminishing their impor¬ tance, and causing the order itself I to look almost puny and meagre, while the pediment looks heavy and clumsy. There has been a good deal of mystification about determining the proportion of pe¬ diments, and special methods have been devised for that purpose, which, however ingenious in them¬ selves, as such, are anything but ar¬ tistic, or calculated to secure pleas¬ ing proportions. Discarding all such methods, it may be laid down as a safe general rule, that the height of the tympanum should accord pretty nearly with that of the entablature beneath the pedi¬ ment, and not greatly exceed it, under any circumstances. Such is the proportion which Wilkins ap¬ pears to have observed for the pe¬ diment of the London University College; and although that build¬ ing has a decastvle portico, the pe¬ diment does not appear too low, whereas that of the National Gal¬ lery is so, the height of the tym¬ panum being there less than that of the entablature, notwithstanding that the portico is octastyle. The ancients generally made the pediment contribute largely to the embellishment of the structure, by sculpturing its tympanum with figures in high relief, and in some instances by setting it back, and placing entire statues against it; 326 'ED PEDIMENT. PED and for such display of sculpture the pediment eminently recom- ! mends itself, both by its conspicu¬ ous situation, and by offering a far ampler surface for such purpose than any other part of the edifice ; one, moreover, which not only re¬ quired a higher decoration, for the sake of consistency, but an in¬ creased degree of it, in order to | produce artistic climax and com¬ pletion. Yet it must be confessed that if its situation marks out the pediment as a very proper place for making a display of decoration, its shape is by no means well adapted for a composition of figures, ex¬ cept it be that it compels them to be arranged symmetrically, and the principal one to be directly in the centre. Be the subject what it may, the figures must always be disposed in nearly the same man¬ ner, and not only very convention¬ ally but very forcedly, particularly towardsthe extremities,—an incon¬ venience that might be easily over¬ come by confining the figures to the centre of the tympanum, putting there a group of three or five, and either leaving the rest of the tri¬ angular space to be quite plain, or else filling it up with mere orna¬ ment. While this would certainlyjbe a rather less expensive mode than that now practised, and an equally rational one, its not having been adopted before ought to be itself some recommendation of it, as being a laudable infringement of copyism, conventionalism, and routine. Besides sculpture within them, pediments are frequently surmount¬ ed at their angles and apex with acroteria, namely, low pedestals, upon which are placed either single figures or groups, or else vases, trophies, or other ornaments; an example of which is furnished by Spencer House, in the Green Park, and still more strikingly by the portico of the East India House. The practice of placing statues upon pediments appears to have originated with the Romans, and is somewhat analogous in taste to that of putting them on the summit of monumental columns; for in such situations human figures show only in their general mass as sculptural accessories to the structure, and at a little distance, or seen in a ge¬ neral view of the building, produce scarcely more effect than so many pinnacles, which last are infinitely more characteristic of Gothic ar¬ chitecture than in accordance with the character of a classical portico. In Italian and modern architec¬ ture generally, the pediment is em¬ ployed as mere decoration in com¬ positions for the dressings of both doors and windows, which prac¬ tice, like that of applying columns for the same purpose, has been condemned by some in the most unqualified manner; and one writer has vituperated, and endeavoured to bring it into disgrace, by com¬ paring pediments over doors and windows to—cocked hats ! The resemblance which he perceives, or fancies, between a cocked hat and a pediment is not a particu¬ larly flattering one ; but if it exists at all, the injurious comparison holds equally good with regard to a large pediment as a small one; therefore, whether it be that over a portico or over a window, the shape itself is, in either case, the most unfortunate one of a cocked hat; yet, as cocked hats are now gone quite out of fashion, the unlucky resemblance to them is not at all likely to be detected. In matters of decoration, some latitude—some little departure from strict archi¬ tectural logic—is allowable; other¬ wise a very great deal in Italian or modern architecture must be pro¬ nounced decidedly faulty. If it be a solecism to place pediments whose form is derived from that of a roof, over windows, or where no roof exists, the same objection lies against applying entablature whose cornices resemble the horizontal 327 PED PEDOMETER. ones of a roof, to mere openings in the wall; and in like manner, if it be a gross impropriety to flank windows with small columns, it must be as great, if not a greater one, to introduce, merely for the sake of decoration, a large order whose columns are partly buried in the wall, and support nothing but an entablature, or pieces of it, wholly unnecessary in themselves, and put there only that the columns may appear to support something. Again, as to the objection which has sometimes been urged against pediments over doors within a building, namely, those intended I to throw off rain, they should be i introduced only in external situa¬ tions,—it partakes of the same kind of hypercriticism as the other ; or, if strict rationality is to be uni¬ formly enforced in architectural design, we must condemn a great deal in the Gothic style as being t exceedingly licentious and irra¬ tional; for in that we find a great many members and features origi¬ nating in forms intended for pur- 1 poses of actual service externally, converted into mere interior de¬ coration ; for instance, embattle- ments on the tops of screens, minia- I ture buttresses for ornament instead ; of strength, miniature spires, and miniature blank windows in orna¬ mental panelling. Pediments are generally placed j only over the windows of the principal floor of a building, to which they serve to give distinc¬ tion and importance. Window pediments are either angular or [ curved ( i. e. segmental), and both I forms are frequently introduced together, and placed alternately, in which case it is usual to place an angular pediment over the cen¬ tre window. Sometimes the centre window alone is crowned with a pediment. When all the pedi¬ ments are alike, they are almost invariably angular, although there are instances of the contrary, as PEL in Bridgewater House, where Mr. Barry has given segmental pedi¬ ments to all the windows of the principal floor, and has even put them over the centre openings of the triple windows; and it de¬ serves to be further remarked, that he has enriched their tympanums with sculptured ornament—a de¬ gree of decoration very rarely in¬ dulged in. A far more remarkable instance—perhaps a unique one— ■ may be seen in the house lately erected for Mr. Hope in Piccadilly, ! large segmental pediments being there placed over windows consist¬ ing of two openings, consequently forming square, or nearly square, instead of upright compositions, j In that instance, too, the pedi- 1 ments are filled in with sculpture; the figures, however, are not ex- \ actlv confined to the pediments, > but come somewhat lower down, the horizontal cornice being partly suppressed for that purpose. Pedometer, in mechanics, an instru¬ ment in the form of a watch, con¬ sisting of various wheels, with the teeth catching in each other, and which, by means of a string fastened to anything in motion, numbers the paces gone over from one place | to another. Peek, in navigation, a name given to the upper corners of sails extended by a gaff, or by a yard crossing the mast obliquely, as the mizen-vard of a ship. The upper extremity of those gaffs and yards is also called the peek. To ‘ peek the mizen’ is to put the mizen-vard perpendicu¬ lar to the mast. Peek-halyards, the ropes or tackles by which the outer end of the gaff is hoisted. Peg-tankard, an ancient species of wassail-bowl, used in the time of i Queen Elizabeth. It held two quarts, and had generally a row of seven pegs, dividing the height into eight equal parts, each containing half a pint. Pelasgic Life. In reference to the 328 EL PENTELIC. PER Pentagon, a figure of five angles and Pelasgian people as early settlers in Greece, the Right Honourable W. E. Gladstone, in his recent admirable work, ‘ Studies on Ho¬ mer,’ says, “ For the first agricul¬ tural settlers must often be dwellers in woods. It may be said that in the United States, at the present day, the proper name for an agri¬ cultural settler is ‘ backwoodsman.’ In British Australia, they who pass beyond the limits of existing settlement, in order to extend it, are said to go into the bush. Thus the idea at the root of the Lycian name is in all probability twin, or rather elder brother to that which properly would indicate the agii- cultural settler.” Pelasgus. Taken literally, Pelasgus is the son of the Earthborn, and the name given to the Pelasgian race. What the passage signifies evidently is, that by ancient tradi¬ tion the Pelasgians were the first occupants of the country. Thucy¬ dides describes the spot or building called rU\a bent. The third roller is placed behind the first two, and it is the I height of this roller, with respect I to that of the other two, that de- 1 termines the degree of curvature i of the plate : it is therefore made capable of adjustment by set- 1 screws, and being placed to the proper height, and the machine set 1 : in motion, the plate is passed be¬ tween the first two rollers, till, coming In contact with the third, it rises upward and takes the form of a curve. Platina yellow, is, as its name im¬ plies, a preparation from platina, which affords a series of yellow pigments, the deep colours of which 340 PLA PLATINUM. PLU resemble the Terra di Siena, but are warmer in tone and richer in colour and transparency, much re¬ sembling fine gall-stones, for which they are valuable substitutes. They work well, and are permanent both in water and oil, when carefully prepared ; but any portion of pal¬ ladium in the metal from which they are prepared neutralizes their colour and renders them useless. > Platinum is found in the metallic state alloyed with other metals, but not in large quantities. It is not so white a metal as silver, but is very malleable and ductile, either when hot or cold. No fur¬ nace can melt it; but by the oxyhy- drogen blow-pipe, or by a voltaic current, it is capable of being fused, and may be dissipated in the air. Alone it is insoluble in nitric acid, but when alloyed with other metals it is soluble. Plenum, in physics, a term used to signify that state in which every part or space of extension is sup¬ posed to be full of matter. It is used in opposition to vacuum. \Plinth, a square member forming the lower division of the base of a co¬ lumn, etc.; also the plain project¬ ing face at the bottom of a wall, im¬ mediately above the ground. In Gothic architecture the plinth is oc¬ casionally divided into two stages, the tops of which are either splayed or finished with a hollow moulding, or are covered by the base inould- ings. Plinth, the square footing below the bases of Ionic and Corinthian co¬ lumns. In Grecian architecture plinths do not appear to have been employed, the bases of the columns resting upon the upper step of the building. The Latin viorAplinthus is derived from the Greek, signifying a tile. Plinthus, any rectangular parallelopi- ped ; a brick or tile. Pliny, whose villas were by the Ro¬ mans objects of much attraction for their design and ornament, was a person of excellent judgment in all the useful arts, and, living under Trajan, had an opportunity of see¬ ing the performances of and of ad¬ vising with Apollodorus, one of the greatest architects that any age pro¬ duced : whether artists or masters employed by Pliny, or Pliny him¬ self, designed these villas, is not to j he determined; but Pliny was per- ' fectiy acquainted with the whole that was necessary to be under¬ stood in their situation and dispo¬ sition. Plotting, among surveyors, the art of describing or laying down on paper, etc., the several angles and lines of a tract of ground surveyed by a theodolite or like instrument, or a chain. Plotting-scale, a mathematical instru¬ ment used in plotting ground, usu¬ ally of box-wood, sometimes of brass, ivory, or silver, either a foot or a foot and a half long, and about an inch and a half broad. Plug-rod the air-pump rod of a Cor¬ nish engine. The tappets which give motion to the valve are fixed upon these rods. Plumb, in ship-building, signifies to be perpendicular. Plumbayo forms grey tints of greater permanence and purity than most blacks in general use, and it is now employed for this purpose with approved satisfaction by ex- | perienced artists. Plumb-line, in architecture, etc., a I line perpendicular to the horizon, ] made by dropping a plummet. 1 Plummer-block, a short carriage or support for a shaft to turn in, with a flat base to bolt on a frame. Plummet, in carpentry, navigation, etc., a weight of lead hung on a string, by which depths are ascer¬ tained and perpendicularity dis¬ cerned. Plum-tree, a handsome wood, a na¬ tive of Europe, used principally in turning, and in Tunbridge works; in the endway of the grain it re¬ sembles cherry-tree. 341 PLU PNYX. Plus, in algebra, a term commonly used for more, and denoted by the character +, as 6 + 10 = 16, in contradistinction to —, or minus, less, as 16 — 10 = 6. j Pluteus, the wall which was some¬ times made use of to close the intervals between the columns of a building, and was either of stone or some material less durable. The latter method was adopted only in places under cover, whence that kind of building was called opus intestinum. The pluteus was also a kind of podium, intervening be¬ tween any two orders of columns placed one above the other. The word is used in this sense in the description of the basilica and the scene of the theatre. The pluteus has been adopted between every two orders of columns in the ex¬ terior of all the theatres and am¬ phitheatres of the Romans which are known. Pluviometer, in the arts, a rain- gauge, an instrument to measure the quantity of rain that falls. Flyers, in mechanics, a kind of ba¬ lance used in raising or letting down a drawbridge. Plying to windward, in navigation, the endeavouring to make a pro¬ gress against the wind. Pneumatics, the properties of air or fluids; a branch of hydrostatics. Pnyx, a name given to a place near Athens, at which assemblies were held for oratory, and for the dis¬ cussion of political affairs of the state; the ancient place of the Athenian parliament. According to Plutarch, who has described the change effected by the Thirty Tyrants in the aspect of the ora¬ tory, it was turned from the sea in order to divert the assembled people from being reminded by their orators of maritime affairs, the basis of Athenian dominion. No traveller, it is said, has hitherto remarked the circumstance of the position of the ancient city wall, by which the Pnyx was doubtless POI enclosed during and after the Pelo ponnesian war. Plutarch furthe; remarks : “ Themistocles did no' bring the Piraeus into the city, a Aristophanes would have had it but he joined the city by a line o communication to the Piraeus, am the land to the sea.” This mea sure strengthened the people against the nobility, and made them bolder and more intracta ble, as the power came with wealtl into the hands of masters of ships mariners, and pilots. Hence ii was that the oratory in the Pnyx i which was built to front the sea was afterwards turned by the Thirty Tyrants towards the land, as they believed a maritime power to bt inclinable to a democracy, wherea: persons employed in agriculture would be less uneasy under an oli¬ garchy. Podium, in Greek architecture, a continued pedestal, for supporting 1 a row of columns, or serving for a! parapet, or forming a sort of terrace, as the podium of a theatre or am¬ phitheatre. It consists of a plinth, base, die, and corona, all which ) were continued without interrup-' tion around three sides of the * building. The podium was also , adopted in the scenes of theatres; and here, instead of being unin- terupted, it was frequently broken round the basis of the columns, and formed what are commonly « called pedestals. Vitruvius seems i to consider the podium as a pede- ; stal continued the whole length of a building, and to have been so i called both when there were pil¬ lars placed on it, or only supported by a wall. When pillars were placed on the sides of buildings, sometimes, instead of having the podium continued the whole length in one line, it was made to break forward under every pillar, which part so advancing was called the stylobate, and that which was be¬ twixt the pillars under the wall, was the podium. j 342 POLARIZATION. 5 OI °ointed or Christian Architecture had its rise about the twelfth century. Very many beautiful ex¬ amples exist in England. It was j also employed in Germany. Mr. \V. Pugin says, that Pointed archi¬ tecture does not conceal her con¬ struction, but beautifies it. A buttress in Pointed architecture at once shows its purpose, and di¬ minishes naturally as it rises, and has less to resist. Here are the i true principles of Christian archi- I tecture, by the conversion of an essential support of the building into a light and elegant decora¬ tion. Point, in navigation, one of the thirty-two divisions into which the circumference of the horizon and the mariner’s compass are distinguished, each comprehending 11° 15'. Point of horse, in mining, the spot where the vein is divided into one or more branches. Polacre, in navigation, a merchant vessel of the Mediterranean, having three pole-masts, without tops, caps, or cross-trees, with a bow¬ sprit of one piece. ! Polarization. If a round hailstone drop upon the sloping roof of a house, it will act, as regards its rebound, just in the same manner whether the slope be towards the north, south, east, or west. But this will not be the case with an arrow under the same circum¬ stances, because it has a distinction of sides, and its behaviour will vary according as the plane of its barbs is parallel with the eaves or with the rafters of the roof, or in¬ clined to both. A bullet in its flight from a gun has also sides to its motion (though not to its form), because it revolves on an axis, which may be vertical, horizontal, or inclined: but if shot from a rifle, it has no such sides, because, though spinning on an axis, that axis has, by a particular contri¬ vance, been made to coincide with POL its line of motion, so that it pre¬ sents the same aspect above, below or on either side. Now if these projectiles were too small or too rapid for us to discover the reason of these differences, we might still observe the differences themselves, and should express them by saying that the motion of the arrow or the gun-bullet possessed polarity, or polarization, which was not the case with that of the hailstone or the rifle-bullet. Polarity, then, means simply a difference of sides. That a ray of light should (in some cases) possess this property is not perhaps so wonderful or un¬ expected as that man should have been able to detect a fact so refined and remote from common observa¬ tion, and even to distinguish dif¬ ferent varieties of it, and investi¬ gate its laws. Indeed, these must be regarded as the very penetralia of physics, the very inmost secrets of Nature that man has been en¬ abled to wrest from her. If the measurable spaces occupied by the waves of light be minute, how far less, in all probability, must be those immeasurable spaces to which its vibrations are confined (which even in sound are mostly inappre¬ ciable, though the waves occupy many feet); yet it is to the posi¬ tions of these inconceivably mi¬ nute vibrations that the differences of polarization are due. Poldway, coarse sacking for coal- sacks, etc. Pole-masts, in navigation, are those made of single trees or spars, in contradistinction to those made of several pieces. Pole-plate, a small wall-plate used in roofs to receive the pitch of the rafters. Polroz, in mining, the pit underneath a waterwheel. Polychromy is the art and practice of painting in positive colours, either on flat surfaces or sculp¬ tured forms, and has been referred for its origin to other than sesthe- >43 PORCH. POL tic motives. The object of poly- chromy is to heighten the effect of architectural decoration, either by causing a more just subordination of the various parts than can be obtained by mere chiaroscuro, or in supplying deficiencies that could not be so well filled up by any other means. Professor Cockerell, who travelled and learned much in Greece, was the first who brought it to light in this coun¬ try. This very interesting deco¬ rative art had its origin doubtless in Egypt; but the Greeks excelled, as in all art, by the existing evi¬ dence of the temples of their per¬ fection of architectural art. The interior decorations of Pompeii are also evidences of a refinement of taste, and in Gothic polychromy the designers and operatives have shown some' talent. A free and bold style in arabesque prevailed from the time of Henry III. until the close of the reign of Edward III. Bright and lively colours were applied to masses, and the grounds covered with compositions of foliage and birds, animals and human figures ; sometimes in one tint, sometimes in varied colours. Many beautiful examples still exist in our cathedrals and some parish churches. Polyfoil, an ornament formed by a moulding disposed in a number of segments of circles. Polystyle, having a number of co¬ lumns. Where columns occur be¬ hind columns, as where a portico has inner columns, like that of the Royal Exchange, such portico may be termed polystyle. Pomel, a boss or knob used as an or¬ namental top of a conical or dome- shaped roof of a turret, etc. A large copper ball or pomel is on the summit of a timber spire of Lincoln cathedral. Pons (Latin), a bridge. The most ancient bridge upon record is the one erected by Nitocris over the Euphrates at Babylon. POl Poon wood, of Singapore, is of a ligh porous texture, and light greyisl cedar colour; it is used in ship building for planks, and makes ex¬ cellent spars. The Calcutta pool is preferred. Poplar wood. There are five species common to England, of which the abele, or great white poplar, and the Lombardy poplar, are most used. The woods are soft, light, easy to work, suited for carving, common turnery, etc. Poppets, perpendicular pieces that are fixed on the fore and aftermost parts of the bulgeways, to support the ship while being launched. Poppet-head, that part of a lathe j which holds the back centre, andi can be fixed on any part of the bed. Poppy, an ornament representing the poppy-head, used on the tops of the upright ends or elbows which terminate seats, etc., in churches. > Poppy-head, in architecture, a carved 1 ornament at the apex of a standard or open seats in Gothic churches, also carved into an ornamental finial, pomel, or crest, etc. Porcelain clay, in mineralogy, a sub¬ stance of great infusibility, derived from disintegrated felspar. Porch, in architecture, a roof sup¬ ported on pillars before a door; a kind of vestibule supported by pil¬ lars. Any small portico consider¬ ably lower than the main structure J to which it is attached may be so ; termed, in contradistinction from ! one carried up the height of the building, or as high as the principal cornice. Porches were used in Nor¬ man architecture, in Early English, and commonly in subsequent dates. When the fashion of building houses on quadrangular plans was discon¬ tinued, a porch of at least two stories, and sometimes the whole height of the building, succeeded the gate-house. Low porches had been used as entrances from inner courts from an early date; and of the time of Henry VIII. one may 344 POR PORTS. be mentioned at Cowdry, attached to the door leading from the court to the hall. Pores, small interstices between the solid particles of bodies. Porisms, in geometry, a name applied by the ancients to certain compre¬ hensive and indefinite problems. Port, in navigation, the larboard or left side of a ship; as ‘ a-keel to port ’ is an inclination to the lar¬ board side. Ports, the holes in the ship to run the guns out. Port-lids, shutters to the ports. Ports and buildings constructed in water. Vitruvius writes: “The op¬ portunity which presents itself of giving some account of ports, and by what means protection may be afforded to ships from the elements, ought not to be neglected. The positions best adapted by nature to such a purpose are bays with capes and promontories at their extremi¬ ties, from which the shore recedes inwardly in a curved line. Upon shores of this description, docks may be built or porticoes erected, or a channel cut from the port to the emporium, defended by towers on each side, in which machines may be constructed for throwing booms across the passage. If, how¬ ever, no situation can be found capable by its formation of protec- ing vessels against the violence of the sea, we must search for a spot where a promontory presents itself on one side, and where no river discharges itself so as to oppose its application to the purposes of a harbour, and supply the want of a corresponding projection on the other by building walls and but¬ tresses. The walls, which it be¬ comes necessary in this case to construct in the water, may be thus formed: sand should first be procured from that part of the coast lying between Carnac and the promontory of Minerva, and mixed with lime in the proportion I of two parts to one; then rows of POR grooved beams must be driven in the water, connected by oaken planks, and bound together by chains. The surface of the ground below the water, on which the wall is to be raised, must then be madeeven by means of transtilli,and the space comprehended between the beams filled with a composi¬ tion consisting of rough stone and cement, made in the manner just described. Such is the quality of the sand produced in these spots, that the composition becomes a solid wall.” Port the helm. In navigation this phrase directs a ship’s course fur¬ ther to the right, or starboard, by putting the helm to larboard. Porta (Latin), the gate of a city, cita¬ del, or other open space, enclosed by a wall, in contradistinction to janua, which was the door or en¬ trance to any covered building. Portal, the arch over a door or gate¬ way ; an entrance under cover. Portcullis, a strong defensive frame¬ work of timber, hung in grooves within the chief gateway of a for¬ tress, or a castle, or an edifice of safety: it resembles the harrow, but is placed vertically, having a row of iron spikes at the bottom, and is let down to stop the passage in case of assault. Portico, in architecture, a covered walk supported by columns, and usually vaulted ; a piazza or arched pathway. (For the different plans and denominations of porticoes, see ‘ Rudimentary Architecture,’ Part I.) Porticus (Latin), a walk covered with a roof which is supported by columns. A portico was either attached to temples and public buildings, or it was built indepen¬ dent of any other edifice. Porticus (deinde ). In the houses of the Roman citizens, between the atrium (hall, or servants’ room) and the inner court, there was usually a room called the tablinum (corri¬ dor), mentioned by Vitruvius. This 345 PORTICUS. POR porticus lay betwixt the atrium and the cavaedium. The reason for his giving it this round form may be upon two accounts: first, to give a greater grace to its pro¬ jection, and to make the forepart of it serve for a more beautiful vestibulum to the house; and in the next place, as being designed for a shelter in tempestuous weather, it the better broke the force of those winds that blew on that side than if it had been more square. Porticus. By the Romans this was a common name given to all build¬ ings that had walks under the cover of a roof or ceiling, sup¬ ported by pillars or pilasters, though differently called, according to the disposition of the pillars: when placed on the outside of a building, as round some of their temples, it was called peripterium ; when these ranges of pillars were within a room, as they were some¬ times in their triclinia, basilica, atria, and temples, the void space betwixt the pillars and the side walls was called ala; but when pillars surrounded courts, and had walks betwixt them and the walls, these ranges of pillars were called peristylia, and the walk betwixt was called a porticus. Portland stone, an alkaline sandstone, of a dull whitish colour, heavy and moderatelyhard, and somewhat flat texture, and composed of large rounded grit, cemented together by an earthy spar, and intermixed with numerous glittering spangles of pure spar: the grit splits in the cutting of the stone, so that it is capable of being brought to a sur¬ face very smooth and equal: it will not strike lire with a steel, and burns to a slight ashen hue. It has been and is much used for all kinds of buildings, particularly in the large structures in London: it is brought from the island of Portland, in Dorsetshire. Post, an upright timber in a building; those used in modern roofs are POM called king-posts or queen-posts' according to their number and po sition. Post Meridiem ( P.M.), after mid-day Postern, a small doorway or gateway at the back of a building; a smal; doorway for private communica¬ tion with the exterior of a castlt or fortress. Postique, in architecture, an orna¬ ment of sculpture superadded wheni the original plan has been com¬ pleted. Pot-metal, a species of stained glass, the colours of which are incorpo¬ rated within the glass while in a state of fusion. Poudrette, a French word, signify¬ ing powdered dung ; but the word is applied, when treating of human excrement, in its meaning to the solid of that soil after the liquid manure has discharged itself. In a vine-growing district near Paris (see article Fosses d'aisances) pou¬ drette was used for manure, and, £| although the application of it pro- fj duced a great abundance of fruit, yet the wine proved very inferior { to that which had been previously ; I made on the same ground. Power, in mechanics: this denotes a « force which, being applied to a machine, tends to produce motion or pressure. Power, horse, in mechanics, an ex¬ pression used to denote the power of a steam-engine, that is to say, how many horses’ work it will save. If a horse standing still can by his strength keep a weight of 169lbs. from falling, when suspended over a pulley, he will exert 121 lbs. at two miles per hour; lOOlbs. at three; 81 lbs. at four; 641bs. at five; 49lbs. at six; 361bs. at seven; 25lbs. at eight; 16lbs. at nine; 9 lbs. at ten ; 4 lbs. at eleven ; and lib. at twelve miles per hour. Power-loom, in mechanics, a loom moved by the mechanical force of steam, wind, water, etc., as con¬ tradistinguished from handweav¬ ing. 346 PRISM. ’OY °oyntell, paving formed into small lozenges or squares laid diagonally. °rcecinctiones, the passages or corri¬ dors which separated the several ranges of seats in an ancient Ro¬ man theatre. Pressure of fluids consists of two kinds, elastic and non-elastic. The first is comprehended in the science of pneumatics, the second in that of hydrostatics. Both classes of fluids deviate from solid substances in their greater distribution of any pressure to which they may be subjected. Thus solid bodies press downwards only by the force of gravity; all fluids, on the contrary, press not only in this direction, but upwards, sideways, and every way equally. The incompressi¬ bility of water renders it service¬ able by this principle, in the hy¬ drostatic press. Preventer bolts, those which are driven at the lower end of the pre¬ venter plates, to assist the strain of the chain-bolts. Preventer plates, in ships, plates of iron below the links of the chains. Pricker, a thin piece of iron, used to make a hole for the fusee or match to fire a blast. Prill, a solid piece of ore, a speci¬ men. Priming, the effect engendered by having too little steam room in the boiler of a steam-engine. Minute particles of water being carried into the cylinder, collect in a body, which obstructs the passage of the piston, and causes a considerable loss of power. Prince’s metal, in metallurgy, an alloy of copper, in imitation of silver, in which the proportion of zinc is greater than in brass. Principal brace, a brace immediately under the principal rafters or pa¬ rallel to them, in a state of com¬ pression, assisting with the princi¬ pals to support the timbers of a roof: they are employed in the present roof of St. Paul’s church, Covent Garden. PRO Priory, a monastic establishment for the devotional requirements and maintenance of a religious frater¬ nity, under the government of a prior. Many priories were for¬ merly scattered over Britain. Prism, in geometry, a body or solid whose two-thirds are any plane figures which are parallel, equal, and similar, and its sides paral¬ lelograms. Prism, in optics, a triangular bar of glass, well known from the effect it produces on a ray of light trans¬ mitted through it: this effect is a decomposition of the light into its component emanations, consisting of the three primary colours and the secondary tints arising from their intermixture, which together form what is termed the solar spectrum. The lensic prism is a new optical glass, in which the powers of the lens and prism are combined. Prison, an edifice, unfortunately mostly of large dimensions, for the confinement of persons warring against society. Profile, the outline of a series of mouldings, or of any other parts, as shown .by a section through them. Profile of an Order, in architecture, an assemblage and arrangement of essential and subservient parts. That profile is preferable wherein the parts are few, varied, and fitly applied. Some member should pre¬ dominate in each division, which it should appear the office of the other parts to fortify, support, or shelter. In a cornice the corona is sup¬ ported by modillions, dentils, ovo- los, etc., and sheltered and covered from the effects of the weather by its cyma or cavetto. Projectile, in mechanics, a body put in motion by an external force. Projectiles, in mechanics, that branch which considers the mass, velocity, range, etc., of a heavy body pro¬ jected into void space by an exter¬ nal force, and then left to the free action of gravity. 347 PROPORTION. PRO Projection, in geometry,drawing, etc., a plan or delineation ; in chemistry, the crisis of an operation. Projecture, in architecture, the out- jutting or prominence which the moulding and members have be¬ yond the plane of a wall or column. Prolate, in geometry, an epithet ap¬ plied to a spheroid produced by the revolution of a semi-ellipsis about its long diameter. Pronaos, the area immediately before a temple. The term is often used for the portico in front of a build¬ ing. The porticus in one front corresponds to the pronaos in the other : in some temples, the cella was entered through both. The generality of Grecian temples had two approaches. Proportion, in architecture, the mag¬ nitude of one part as compared with some other. The term ‘ pro¬ portion’ is used absolutely in the sense of ‘good proportion,’although everything that has shape has pro¬ portions of some kind or other. The subject of proportion has been greatly mystified by winters, who have laid down certain fixed pro¬ portions as the best of all on every occasion, and as the ne plus ultra of artistic taste. But fixed propor¬ tions can be followed mechanically by every one alike; whereas it re¬ quires ability to deviate successfully from routine measurement, and ap¬ ply the poco piu or the poco meno as the particular occasion or the particular effect aimed at may re¬ quire—at least, justify. It is the eye that takes cognizance of pro¬ portions ; and the architect’s own eye ought to be quite as correct as that of other people. Proportion, that branch of mathe¬ matical science which defines the ratio of numbers or quantities to each other. Proportions of rooms should be suited to the purposes for which they are used; all figures, from the square to one and a half the breadth of the room, may be employed for the PR( plan. Some have extended th- plan to a double square. Gallerie may be from five to eight time their breadth. The height, if witl flat ceilings, is not required to be S( great as in those that are covered The height of square apartment: should not exceed five-sixths thi side of the square, nor be less that four-fifths; but in rooms that an oblong, the height ought to b< equal to the breadth. The heigh’ of square rooms that are coveret should be equal to one of the side; of the square ; but covered oblon§| rooms require a height equal to thf breadth, added to one-fifth, one quarter, or, at most, one-third ol! the difference between their length; and breadth. The height of gal¬ leries should be from one and three- i fifths at most, to one and one-third at least, of their breadth. Cornice. 1 , and dressings in the interior oil houses are always to be kept mori delicate than those on the out- 1 side. Propylaeum, in Greek architecture I the porch of a temple or great hall. Propylcea: the entrance to a Greek ; temple, a sacred enclosure, con- : sisted of a gateway flanked by buildings, whence the plural of the ! word. The Egyptian temples gene-, j rally bad magnificent propvlaea, con¬ sisting of a pair of oblong truncated pyramids of solid masonry, thefaces I of which were sculptured with hie¬ roglyphics. The word, however, i is generally used to signify the en- ' trance to the Acropolis of Athens, which was the last completed of the great works of architecture | executed under the administration 1 of Pericles. Pausanias relates that j “ there is only one entrance to the acropolis, it being in every re¬ maining part of its circuit a preci¬ pice, and fortified with strong walls. This entrance was fronted by a magnificent building, called the propvlaea, covered with roofs of white marble, which surpassed for beauty, and the dimensions of the •RO PRUSSIAN BLUE. PRU marble, all that hehad before seen.” The buidingwas commenced during the administration of Pericles, and finished in five years, Mnesicles being the architect, at the expense of 2,0.12 talents, or nearlv£464,000 sterling. There were five gates to the propylaea, and before it stood two lofty piers, on each of which was placed an equestrian statue, supposed to be the sons of Xeno¬ phon. On the right of the pro¬ pylaea was the temple of Victory without wings, whence is a pro¬ spect of the sea ; andfrom this place it was said that Jilgeus threw him¬ self down headlong, and died. On the left of the propylaea was an edifice adorned with paintings, the work of Polvgnotus, of which, says Pausanias, though some were ef¬ faced by time, there still remained those of Diomedes and Ulysses, the one bearing off the bow and arrows of Philoctetes from Lemnos, the other, the Palladium from Troy, j There were those also of Orestes | slaying iEgisthus, and Pvlades en- ' countering the sons of Nauplius, who had come to succour iEgis- thus; Polynexa, at the sepulchre of Achilles, about to be sacri¬ ficed, and Ulysses addressing him¬ self to Nausicaa and her maidens, as described by Homer. Several other pictures in the same place are described by Pausanias. These three contiguous buildings origi¬ nally formed one front, occupying the whole breadth of the rock from 1 side to side, at its western end, so that the only admission into the i acropolis was through the middle building, the five gates of which are still remaining, and prove it to have been the propylaea. It may be ' supposed that the Hermes Propy- laeus was here placed, and perhaps the Graces, a piece of Sculpture by the hand of Socrates, in which that celebrated philosopher, deviating from the practice of the sculptors who preceded him, had repre¬ sented them not naked but clothed. Other sculptors are also men¬ tioned by Pausanias who seem to have decorated this stately en¬ trance. Proscenium, the area in front of the scene of a theatre, which was per¬ ceived when the pulpitum was re¬ moved, and when it is probable the temporary scenes were taken away in order to exhibit the front of the permanent scene. Prostyle, a temple which has a por¬ tico in one front, consisting of in¬ sulated columns with their entabla¬ tures and fastigium. When the temple had a portico in both fronts, it was termed' am phi-prostyle, or prostyle in all parts. Protractor, in surveying and trigo¬ nometry, an instrument by which angles taken in the field with a theodolite-circumferentor are re¬ presented on paper. Prow, in navigation, the head or fore¬ part of a ship, in opposition to the poop or stern. Prussian Blue, otherwise called Ber¬ lin blue, Parisian blue, Prussiate of iron, cyanide of iron, or, in lan¬ guage more pedantically chemical, per-ferro-cyan ate of iron, with alumine, etc., is rather a modern pigment, produced by the com¬ bination of the prussic or hydro¬ cyanic acid, iron, and alumina. It is of a deep and powerful blue colour, of vast body and consider¬ able transparency, and forms tints of much beauty with white-lead, though they are by no means equal in purity and brilliancy to those of cobalt or ultramarine, nor have they the perfect durability of the latter. Prussian Brown is a preparation of Prussian blue from which the blue colouring principle has been ex¬ pelled by fire, or extracted by an alkaline ley : it is an orange-brown, of the nature and properties of Siena earth, and dries well in oil. Prussian Green. The pigment cele¬ brated under this name is an im¬ perfect prussiate of iron, or Prus- - | PRU PUMP. PUM sian blue, in which the yellow oxide of iron superabounds, or to which yellow tincture of French I berries has been added, hut is not in any respect superior as a pig- , ment to the compounds of Prussian blue and yellow ochre. A better sort of Prussian green is formed hv precipitating the prussiate of potash with nitrate of cobalt. Prussiate of Copper differs chemically from Prussian blue only in having copper instead of iron for its basis. It varies in colour from russet to brown, is transparent and deep, hut being very liable to change in colour by the action of light or by other pigments, it has been very little employed by artists. , Pryan, in mining, that which is pro- 1 ductive of ore, but does not break in large stones, but only in pebbles with a mixture of clay. ! Pseudo-dipteral, a temple which has \ a single range of columns in the flanks, at the same distance from 1 the walls of the cella as though the temple had been dipteral. ! Pteroma, the spaces between the walls of the cella of a temple and the columns of a peristyle; called also ambulatio. Puddling , in metallurgy, a process in the refining of iron which consists in stirring it actively about. Pulley, one of the six mechanical powers. The pulley is a small wheel turning on an axis, with a rope or chain passing over it. The circumference is generally grooved to receive the rope, which is at¬ tached on the one end to the mov¬ ing power, and on the other to the resisting force. Pulleys are of two kinds—fixed and movable. The fixed pulley gives no mechanical advantage, but is of great utility in altering the direction in which it may be applied. The movable, on the contrary, doubles the power, which may be increased in any ratio by adding to the number of pulleys. In a combination of pulleys, the advantage, however, is greatly diminished by the fric¬ tion of the axles and of the ropes. Too complex a combination there¬ fore would not he of service, as the friction would be increased without a proportional advantage, and from the complexity of the machine tvould he more liable to be put out of order. Pulpit, an elevated stage or desk from which sermons are delivered. Pulpitum, the wooden stage of the theatre upon which the mimic as well as dramatic exhibitions of the Romans were represented. In the Greek theatre, the pulpitum was used only by the histriones, or performers in the drama, and was probably removed before the amusements of the orchestra were exhibited. Pulvinated. A frieze whose face is convex instead of plain is said to he pulvinated, from its supposed resemblance to the side of a cushion, which swells out when pressed upon. Pump, an engine for raising liquids, made in various forms, of more or less complexity of parts and effec¬ tiveness of action, depending in its simplest form upon the external pressure of the air on the surface of the weter, and in other forms deriv¬ ing its power from the abstraction of the air within the tube or barrel. The simplest form of pump is that of the common lift-pump, which consists of a straight tube with two valves, one of which is fitted to the lower end of the tube, and the other is made to slide air-tight in the cavity of the tube or barrel. Both of these valves are adapted to open upwards only, and thus the water ! is admitted and lifted from the lower part of the tube to the dis- j charge aperture above. This pump j acts by the pressure of the atmo¬ sphere upon the external body of water from w r hich the supply is raised, but by the forcing-pump water may be raised above the level to which it is driven by the pressure 350 PUMP. PUM of the atmosphere. The forcing- pump consists of a barrel fitted with a solid piston or forcer, the barrel being also provided with a branch forcing-pipe. The lower part of the barrel and the branch- pipe are each fitted with a valve opening upwards, and by repeated strokes of the piston, the pressure of the air from above being removed, the fluid is brought up to fill the space between the two valves, and being prevented from returning by the lower valve, it passes through tiie upper valve of the branch-pipe into a capacious upper vessel, and there accumulating, may be ejected in a constant instead of intermittent stream. The lift-pump, being simple and economical in construction, is well fitted for extensive works in which the quantity of water to be raised is considerable, and is there¬ fore usually employed in works for supplying water for towns. The pumps used at the Metropolitan and other waterworks are of great size, and deliver immense volumes of water at each stroke. Those used at Haarlem are 63 inches in diameter, and the pistons have a stroke of 10 feet in length. Each | pump delivers 6 tons of water at each stroke. Pumps of this magni- | tude are worked by water or steam power. Those at Haarlem, eleven in number, are worked simultane¬ ously by a steam-engine, having two steam-cvlinders, one within the other, the larger being 12 and the smaller 7 feet in diameter, with a stroke of 10 ft. (See Forcing Pump.) j Pump. Mr. Appold’s centrifugal pump for draining marshes, and for other purposes, will discharge 10 gallons of water per minute, and is only 1 inch diameter: one of the same shape, 12 inches dia¬ meter, will discharge at the same speed of the outside circumference, or -jL the number of revolutions, 1,440 gallons per minute, being ac¬ cording to the square of the dia¬ meter, and not according to the PUM cubic contents. From various ex¬ periments, it lias been found that the larger model with the curved vanes does the most duty, on ac¬ count of its receiving and delivering the water more obliquely : it will discharge 1,800 gallons per minute, with 607 revolutions, but does the most duty at 535 revolutions, dis¬ charging 1,400 gallons; therefore, if a pump 1 inch diameter raise 10 gallons, and another 1 foot dia¬ meter 1,440 gallons, it follows that one gals, per min. 10 feet diameter, of the best shape,will pump 140,000 20 ditto, ditto . . . 560,000 40 ditto, ditto . . . 2,240,000 To do the above duty, the cir¬ cumference of the 20-feet pump would be required to travel 560 yards per minute, which would be only 53^ revolutions, and the 40- feet 26f. From the results of various ex¬ periments, it has been found that the loss of powder would not be more than 25 per cent. It will be observed, the centrifugal force is not so much in the large diameter, on account of the water moving more in a straight line; but that is compensated for by the force being applied to a greater depth of water, being 10 feet in the 40-feet, and only 3 inches in the 1-foot. ft. high. 159 revolutions, with the 1- foot, will raise the water, without discharging any, 1 318 revolutions.4 636 ditto.16 1272 ditto.64 The highest elevation to which the water has been raised with the 1-foot pump, is 67 feet 8 inches, w’ith 1,322 revolutions per minute, being less than the calculated height, which may be accounted for by leakage with the extra strain. While the 1-foot pump is raising 351 a 2 PUM PUNCH. PUN 8 tons of water 5 feet 6 inches high per minute, there is no greater strain on any part of the pump than 160 lbs. on the 6-inch drum, which is equal to a leverage of 3 inches. (See the results of various experiments in the following Table.) It will pass almost any¬ thing that is small enough to go through, there being no valves. A quantity of nut-galls (about £ a gallon) were thrown into the 1-foot pump all at once, when it was at full speed, and they passed through without breaking one. Dimensions of the Pump. Diameter.1 foot. Width.3 inches. Contents.1 gallon. Table of Mean Results of various Experiments with Mr. Appold's Centrifugal Pump. No. of revolutions jer minute of 6-inch drum and pump. Number of gallons raised 5 feet 6 inches high per minute. Equivalent in lbs. raised 1 foot high per minute. Strain in lbs., on a drum of 4 ft. diameter driving one of 6 in. diameter, as measured bv a dynamometer. Equivalent strain on the steam-engine, rated in lbs. raised 1 foot high per minute. Percentage of work done compared with power expended. 400 500 27,500 74 44,400 617 412 600 33,000 80 49,440 667 427 700 38,500 87 55,723 69- 440 800 44,000 94 62,010 70-9 453 900 49,500 100 67,950 72-8 474 1000 55,000 106 75,366 72-9 481 1100 60,500 113 81,479 74-2 495 1200 66,000 118 87,615 75-3 518 1300 71,500 121 94,017 76- 535 1400 77,000 126 101,115 761 563 1500 82,500 134 113,163 72-9 580 1600 88,000 138 120,060 733 595 1700 93,500 142 126,733 73-6 607 1800 99,000 150 136,575 72-5 Pump, marine, a machine to draw water out of a ship’s hold. Pump-chain. This consists of a long chain with valves at proper dis¬ tances, working on two wheels, one above and one below, and passing down through one wooden tube and returning upwards by another. Pump-cistern, to receive the water from the pumps. Pump-dales, pipes to convey water from the pump-cisterns through the ship’s sides. Pumping-engine, a steam-engine for raising water. Punch, in mining, a piece of timber, used as a support for a roof. Punch, a tool for making an impres¬ sion, or for forcing a hole through a plate. Puncheon, a measure of liquids con¬ taining eighty-four gallons. PUN PUNCH ING-MACHINE. PUR Puncheons, small upright timbers in wooden partitions, now usually called studs or quarters; they are placed upright between two posts whose bearing is too great, serving, together with them, to sustain some large weight. Punching and Plate-cutting Machine. The operation of punching holes through thick metal plates requires machinery of a very massive de¬ scription, on account of the violent strains to which it is subjected; and the power of these machines being exerted only at intervals, it is necessary to apply some means of rendering the motion tolerably uni¬ form, and thereby diminishing as much as possible the violence of the strain. This is effected by setting in motion a heavy fly-wheel, so that the power expended in giving a certain velocity to the wheel shall be stored up till the operation of punching commences, which tends to retard the motion : the accumulated power in the wheel will then tend to maintain the speed, and thus an approxima¬ tion to Uniform motion is obtained. The machine consists of a strong frame, at the front of which is a broad slide, moved vertically up and down by an eccentric fixed on the end of a shaft passing length¬ wise through the frame: on this shaft there is a large wheel, which receives motion from a pinion on another shaft carrying the fly¬ wheel and driving-pulleys. The punches, the number of which varies according to the size of the holes, are fixed in the lower end of the vertical sliding-piece, and im¬ mediately under them is fixed a piece of steel, called the dies, which has holes in it to correspond with the punches. The plate in which holes are to be punched is fastened upon a travelling table in front of the machine; and the slide being up, and the surface of the table level with that of the dies, the part where the holes are to be 353 punched is placed between the punches and the dies, so that when I the machine is set in motion, the punches are forced through the I plate by the action of the eccentric, I and the pieces driven out fall j through the holes in the dies: after the punches have risen above the surface of the plate, the tra¬ velling table is set forward to the ' required distance by self-acting apparatus, and the operation is re- , peated by the machine till the re- j quired number of holes has been ! punched. The plate-cutting apparatus con- I sists of two steel-plates, forming a I pair of shears: the lower plate is i fixed on the frame of the machine, j and the upper one is attached to a I slide, as in the case of the punches, acting in a similar manner. The I shears are moved by the same I shaft as the punches, and act while I the punches are being raised: { sometimes they are placed at the top of the punching-slide. Punt, in navigation, a sort of oblong, j flat-bottomed, small boat, with a j square head and stern. Purbeck-stone, an alkaline sandstone, i harsh and rough, of a disagreeable i ash colour, very heavy, and mo- | derately hard ; of a texture not j very compact, but somewhat po- j rous, and composed of an angular j grit, cemented together by an J earthy spar. It cuts freely, and J with a tolerably even or smooth j surface, but will not take a po- I lish: it is used principally in Lon- j don. The quarries are in the island j of Purbeck, Dorsetshire. Purlins, in carpentry, those pieces of timber that lie across the rafters on the inside, to keep them from sinking in the middle. Purple, the third and last of the secondary colours, is composed of red and blue, in the proportions of five of the former to eight of the latter, which constitutes a perfect purple, or one of such a hue as will ' neutralize and best contrast a per- PLR purple. puz feet yellow in the proportion of thirteen to three of surface or in¬ tensity. It forms, when mixed with its co-secondary colour, green, the tertiary colour olive, and when mixed with the remaining second¬ ary orange, it constitutes the ter¬ tiary colour russet. Purple Black is a preparation of madder, of a deep purple hue, ap¬ proaching to black; its tints, with white-lead, are of a purple colour. It is very transparent and power¬ ful, glazes and dries well in oil, and is a durable and eligible pigment, belonging perhaps to the semi-neu¬ tral class of marrone. Purple Lake. The best purple lake, so called, is prepared from cochi- neal, and is of a rich and powerful colour, inclined to crimson. Its character as a pigment is that of a cochineal lake, already described. It is fugitive both in glazing and tint, but used in considerable body, asiu the shadows of draperies, etc., it will last under favourable cir¬ cumstances a long time. Lac lake resembles it in colour, and may supply its place more durably, al¬ though not perfectly so. Purple Oclire , or Mineral Purple, is a dark ochre, a native of the forest of Dean, in Gloucestershire. It is of a murrey or chocolate colour, and forms cool tints of a purple hue, with white. It is of a similar body and opacity, with darker colour than Indian red, which has also been classed among purples, but in all other respects it re¬ sembles that pigment. It may be prepared artificially, and some na¬ tural red ochres burn to this colour, which has been employed under the denomination of violet de mar. Purple wood is from the Brazils, im¬ ported in logs from 8 to 12 inches square, and 8 to 10 feet long, prin¬ cipally used for ramrods, buhl- work, marquetry, and turnery. Purser, the cashier or paymaster of mines; also the paymaster of a ship. Pursuivant, in heraldry, a messenger who formerly attended the king in his wars, or at the council table, and ultimately became herald. Puteal, the enclosure surrounding the opening of a well, to protect persons from falling into it. It was either round or square, from 3 to 4 feet high. There is a round one in the British Museum, made of marble. Putlogs or Putlocks, in building, are short pieces of timber about 7 feet long, used in building scaffolds. They lie at right angles to the wall, with one of their ends resting upon it, and the other upon the poles whieh lie parallel to the side of the wall of the building. Putlog-hole s, small holes left in walls for the use of the workmen in erecting scaffolding. Putty, in the arts, a kind of paste used by glaziers, composed of whiting and linseed oil (with or: without white-lead), beaten toge-') tlier to the consistence of a tough dough. Puzzolano, or Puozzolano, in mine- t ralogv, a volcanic sand of a violet I red colour (the pulvis Puteoli of Pliny), brought from Italy, which forms a cement that hardens under water. It appears to be a species of argillaceous earth that probably has been calcined and then ejected from a volcano. Its constituents \ are silex, alumina, oxide of iron, and a little lime. It w as first dug . out of the earth by the Romans near the town of Puzzoli, not far from Vesuvius. The environs of Rome furnish it equally. It has been found in France in the ex¬ tinct volcanoes of Vivares. There are a few regions exposed to ig¬ neous agency which are destitute of it, but it presents itself under very different physical appear¬ ances, — sometimes pulverulent, sometimes in coarse grains, often I in slag, pumice, tufa, etc. Its colour, which is generally brown, ■ passes to yellow, grey, and black. 354 QUARRY. ?YC The only preparation this material undergoes previous to use is that of pounding or grinding and sift¬ ing, whereby it is reduced to pow¬ der, in which state it is beaten to a proper consistency with a due proportion of lime. Artificial puzzolano is also much used, and is produced by pulverizing the clay, the psammite, or the arene, which is soluted, and the strewing a layer of it, about four-tenths of an inch, on a plate of iron, heated to a point between a cherry-red and forging-neat. It is left till it be raised to the same degree, for a space of time which- varies, for each kind of material, from five to twenty minutes. It must be con¬ tinually stirred with a small rod, in order that the whole of the particles may be uniformly cal¬ cined. Pycnostyle, that arrangement of Greek or Roman columns, in which the intercolumniations are equal to one diameter and a half of the lower part of the shaft. Pyramid, in geometry, is a solid figure whose base is a polygon, and whose sides are plane triangles, their several points meeting in one. Pyrites, in mineralogy, a name given to certain metallic ores contain¬ ing a large portion of sulphur; Quadra, in architecture, a name 1 given by Vitruvius to the square piece, commonly called the socle, used to support the pedestals of statutes, vases, and other orna¬ ments. Quadras, the bands or fillets of the Ionic base, between which the scotia or hollow occurs; also the plinth, or lower members of the podium. Quadrangle, a figure having four an¬ gles and four sides. Quadrant, the fourth part of a circle, being hounded by two radii per¬ pendicular to each other, and a QUA native compounds of sulphur with \ different metals, and more espe- j daily with iron. The term is ! derived from the use to which the i stone was formerly applied, that of I obtaining sparks hv percussion, an j application of pyrites mentioned by Pliny. Pyrites, Copper, in mineralogy, a combination (sulphuret) of copper j and sulphur, being the most com- ; mon ore of copper. Pyrites, Iron, in mineralogy, a com¬ bination (sulphuret) of iron and sulphur, one of the most abundant minerals in nature. Pyrometer, in chemistry, an instru¬ ment for measuring very high tem¬ peratures, depending on the uni¬ form and permanent contraction of pure clay. Pyrometer, a contrivance for ascer¬ taining the temperature of the flues of boilers, by fixing an iron wire at the back of the flue, and connecting it to a lever in front of the boiler, which indicates the de¬ gree of expansion and consequently the temperature. Pyx, Pix, a tabernacle or shrine, a depository for the Host, or con- I secrated wafer, used in Romish ) ceremonies. (See Theoreca.) \ Pyx, in navigation, the box in which the nautical compass is suspended. quarter of the circumference, or 90 degrees. Quadrature, the finding a square equal in area to another figure. Quadrifores, folding - doors w'hose height was divided into two. Folding-doors which opened in one height were termed fores val- vatae, or valvce. Vitruvius directed the doorw'ays to be made wider when these were used, and the height to be increased when the folding - doors were divided in height. The hifores of Vitruvius were two single doors. Quarry, a place underground from 355 QUA QUARTERS. RAC whence are taken marble, free¬ stone, slate, limestone, and other stones proper for building and paving. Quarry, a pane or piece of glass cut in a lozenge or diamond form. Quarter, in heraldry: this word is sometimes used for an escutcheon or coat of arms : there are sixteen quarters required to prove nobility. Quarter (ships), the afterpart of the top-side. Quartern, in building, those slight upright pieces of timber placed be¬ tween the puncheons and posts, used to lath upon. These are of two sorts, single and double : the single quarters are sawn to 4 inches thick and 4 inches broad; the double quarters are sawn to 4 inches square. It is a rule in car¬ pentry that no quarters be placed at a greater distance than 14 inches. Quarter-deck, in ship-building, the short upper deck from the after¬ most end of the main chains to the stern. Quarter-gallery, the projecting con¬ venience and ornament of the top¬ side which is connected with the stern. Quarter-pieces, the carved figures at the aftpart of the quarter-gallery which joins to the taffra.il, and forms the boundary of the stern. Quartering, in heraldry, the act of dividing a coat of arms into four or more quarters, by parting, cooping, etc., by perpendicular and hori¬ zontal lines. The sovereign of Great Britain in the first quarter bears gules, the lions passant, or, etc.; in the second, formerly, azure, three fleurs-de-lis, etc. Quatrefoil, an ornament of frequent E. Rabbet, that part of the keel, stern and stern-post of a ship which is cut for the plank of the bottom to fit into; the edges of plank or deal for bulkheads that are lapped one occurrence in Gothic architecture, formed by a moulding disposed in four segments of circles. Quears, in mining, crevices in lodes. Queen-post, a vertical timber, sup¬ porting the rafters of a trussed roof. Quercitron Lake, or Quercitron Yel¬ low, is what its name implies. It is dark in substance, in grains of a ! glossy fracture, perfectly transpa¬ rent, and when ground is of a beau¬ tiful yellow colour, more durable ■ than the common yellow lakes, al- j though not perfectly permanent. j Quick lime, such lime as is in the | caustic or most active state, and which possesses the greatest power of operating upon different sub¬ stances with which it may come in contact. It is quite the opposite in its qualities and properties to that which has fallen down into a powdery state, in consequence of being saturated with water and carbonic acid gas or fixed air, or which is slaked and become effete, j Quick-work, the short pieces between [ the ports withinside a ship. Quink, in building, a piece of ground taken out of any regular ground- plot or floor : thus, if the ground- plot be oblong or square, a piece taken out of a corner to make a court or yard, etc., is called a quink. Quirk, a small acute channel orrecess, much used between mouldings in Gothic architecture : in Grecian ar¬ chitecture ovolos and ogees are usually quirked at the top, and sometimes in Roman. Quoins of stone, the corners of brick or stone walls: when they stand out beyond the brickwork, they are called ‘ rustic quoins.’ over the other, and wrought square, making each side of the bulkhead j a smooth surface to the distance of two rooms and spaces. Lack, in mining, an inclined plane on RAC RAILWAYS. RAI which the ore and slime are washed and separated. i Rack, a flat bar with teeth on one side, to work into those of a pinion. Racking, in mining, a process of se¬ parating small ores from the earthy particles by means of an inclined wooden frame: the impurities be¬ ing washed off, the ore remaining near the head of the rock is taken from thence, and undergoes toss¬ ing. Radiant point, any point from which rays proceed. Radius, in geometry, the semi-diame¬ ter of a circle, or a right line drawn from the centre to the line of cir¬ cumference ; in anatomy, a bone of the fore-arm, which accompanies the ulna from the elbow to the wrist. Radius-rods, the guiding rods in a parallel motion, jointed to the con¬ necting-links, to counteract the vibratory motion communicated by the beam, by guiding the links so that there is a point. Rafters, in carpentry, the secondary timbers of a house; the timbers let into the great beam. Rag-stone, in mineralogy. The Kent¬ ish rag-stone is a kind of lime¬ stone, much preferred to other stones of a similar nature. It is found in beds varying from 6 inches to 3 feet in thickness, and is com¬ posed of the following substances : carbonate of lime, with a little magnesia, 92G; earthy matter, 6’5; oxide of iron, 0'5; carbonaceous matter, 0-4 = 100. This stone is now much used. Rail or life guards, in locomotive en¬ gines, strong iron rods reaching down within about 2 inches of the rails, to catch and throw to one side any obstruction which may be on the rails. Rails, the moulding ornaments in the top-side, likewise in the head and stern of a ship. Railways: roads in which tracks of iron or other smooth material are laid for the easy passage of wheel- carriages, appear to have been in¬ troduced between the years 1600 and 1650, in the neighbourhood of Newcastle, to facilitate the car¬ riage of the coals from the pits, in ‘ wains ’ or waggons, to the ‘ staythes’ or discharging-places on the Tyne. In 1676 they were de¬ scribed to be thus formed : “ The manner of the carriage is by laying rails of timber from the colliery to the river, exactly straight and pa¬ rallel ; and bulky carts are made, with four rollers fitting those rails, whereby the carriage is so easy, that one horse will draw down four or five chaldrons of coals.” These “ rails of timber” were laid upon transverse timbers or sleepers, and secured with pegs of wood, the sleepers being embedded in the material of the roadway. Before the year 1716, it became the practice to preserve the edges of the rails by nailing thin plates of malleable iron upon their upper surfaces in places where the draught was harder than usual. About the year 1767, cast-iron bars were sub¬ stituted for the wooden rails, and this change is said to have been suggested by the wish of the iron¬ masters to keep their furnaces at work during a season of unusual depression in the market value of their manufactures. These iron bars w r ere found too valuable to admit of a return to the wooden rails, and improvements of various kinds were introduced. Thus the rails were cast in the form of long narrow plates, with a vertical rim along one side (the transverse sec¬ tion resembling the form of the letter L), and thus the wheels of the waggons were retained in their places without the projecting rims or flanges which were required for wheels running on the plain rails or bars. These rails were called ‘ tram’ or ‘ plate rails,’ and thus dis¬ tinguished from subsequent forms of iron rails w'hich were introduced to dispense with the longitudinal 357 a 3 RAILWAYS. RAI timbers heretofore required beneath them, by casting the rails of suffi¬ cient depth to carry their load, and of reduced width, the flanged- wheels being returned to. Mal¬ leable-iron rails were introduced about the year 1815, at coal works in Cumberland, with a view to re¬ medy the defect of frequent break¬ age, to which those of cast-iron were liable : these malleable-iron rails were simply bars of iron from 2 to 3 feet in length, and 1 to 2 inches square ; but the narrowness of their surface was found to injure the wheels so severely, that the restoration of cast-iron rails ap¬ peared likely, when an ingenious invention was made by Mr. Birkin- shaw, who obtained a patent in October, 1820, for his improve¬ ments, which consisted in passing bars of iron,red-hot,between rollers having indentations in their peri¬ pheries, corresponding with the in¬ tended shape of the rails. By this mode malleable - iron rails were rolled in lengths of 12 or 15 feet each, and could be formed in any required shape, the section varying throughout the length, so as to give increased depth and width at the points intermediate between the intended bearing places. The rails now generally used are pro¬ duced in a similar manner, and the permanent way consists of a levelled surface of roadway formed with metalling or suitable ballasting, transverse sleepers, commonly of larch, about 9 feet in length, 8 to 10 inches in width, and about 6 inches deep. These sleepers are laid from 2 feet 6 inches to 3 feet apart, and saddles or chairs of cast iron are fastened upon them with spikes. Two of these chairs are fixed upon each sleeper, at such distance apart that the rails, when placed in them, shall have the in¬ tended distance or gauge between them, commonly 4 feet 8J inches. The rails are parallel throughout, and of a form resembling that of RAI the letter S laid on one side, the depth of the rail being about 5 inches, the width over the top and bottom about inches, and the thickness of the middle vertical rib about | inch ; all the angles of the section being carefully removed by rounding the meetings of the seve¬ ral surfaces. For the ‘ broad gauge,’ in which the rails are laid 7 feet apart, continuous longitudinal tim- ; hers, about 12 inches square, are employed, and connected by cross¬ timbers framed to them. The rails are of a bridged or arched section, and rolled with a projecting plate along each side, bolts passing through which secure the rails to the longitudinal timbers. The theory of a perfect railway requires that it should be level in its vertical position and uniform in direction. Practically, these con¬ ditions are sacrificed within certain limits; but the attainment of great speed and safety, upon the present locomotive system, forbids any very wide extension of them. The con¬ sequence is, that great and expen¬ sive works are required in earth¬ works, bridges, viaducts, etc., to obtain the required inclination of surface and direction; and although the principles of construction are , the same in all, hardly any two j railways are alike in details. In the following Tables, the principal particulars of main lines, branches, amalgamations, date of acts of authority, length of each portion, and total length of each amalgamated line, with amount of cost, or of estimate, or of capital, in round numbers, are arranged with the view of presenting a clear outline of each railway, whether single or combined, arranged as nearly as practicable in a chronolo¬ gical order; the earliest date of the Act for any of the component lines being adopted as the date for \ determining the chronological place for the amalgamated line in the Table. 358 AI RAILWAYS. RAi Bate of Acts. Length of each portion. Total Length. Estimate, Cost, or Capital. 1853 Miles. Miles. Estimate .... £. 37,620 1809 1853 93 6? Parliam. Estimate . 30,300 48,974 1842 40' On lease 50j • 90 1847 1847 1849 1851 1852 1854 J Authorized Cap.. \ Received . . . 2,161,972 2,061,329 1824 f Shares .... \ Loans .... 246,000 82,000 1826 1835 1848 36 f Shares .... \ Loans .... f Shares .... \ Loans .... 110,000 36,666 210,000 70,000 1853 1846 46^ June 30, 1854 . . 73,085 594,446 1833 112£ 5,500,000 Name of Railway, Amal¬ gamation, Main Line, and Branches. ievem and "Wye . . . (Originally Lvdney and Ledbrook) . . . Descending line - ] throughout from ■, Forest of Dean to [ Lvdney Harbour. J Steepest grad. 1 in 40. ;ockton and Darlington ForTramroadfrom Ri¬ ver Tees at Stockton to Witton Park Col¬ liery, with branches Lease of Middlesbro’ and Redcar Line . Lease of Wear Valley, including Bishop Auckland and Wear- dale, Wear and Der went, Weardale Ex¬ tension, Shildon Tunnel . . Purchase of Middles¬ bro’ Dock, etc.. . Financial . . Financial . . Branch to Shildon 1 Tunnel, new Ca- I pital, etc. . . . J Monkland. Amalgamation ofl the Monkland S> and Kirk . . .J Ballochney . . . Slamannan . . . Amalgamation . . Bathgate Minera Fields, etc. . . ondon and N.-Westerr Amalgamation of the Lond. & Birminghan also of the Warwick and Leam¬ ington, and 359 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, of of each Length. Estimate, -Cost, or Capital. and Branches. Acts. portion. Lond. & N.-W. continued. Miles. Miles. £. Peterboro’ Branch, amalgamated with the London & Birm. 1843 Amalgamated Cap.. 8,250,000 Grand Junction . . 1833 86* Original Capital. . 1,957,800 I (with which was Capital at amalga- amalgamated in mation of Chester 1840 the and Crewe . . . 3,098,388 Chester and Crewe) . 1837 20* 458,333 Bolton and Leigh . . 1825 10 201,750 Huddersfld. & Manch. 1845 Manchester & Birm. . Leeds, Dewsbury, and 1857 38* 2,800,000 Manchester . . . 1845 799,300 North Union . . . 1831 22* 730,000 (joined with Lane, and Yorksh. and Preston and Wyre) 1835 19* 400,000 West London . . . Manchester, Buxton, 1836 3 280,000 Matlock, & Midlds. North and South-wes- 1846 11* 421,300 tern Junction . . Birm., Wolverhampt., 1851 4 and Stour Valley . 1846 1,110,000 Buckinghamshire . . Shropshire Union . . 1846 41* 795,000 including the Newton and Crewe . 1846 1 United Capital f 1,500,000 Chester & Wolvrhmpt. 1846 l £3,300,000, ^ 1,000,000 Shrewsby. & Stafford, 1846 J viz.: . . . [ 800,000 Lancaster and Carlisle Besides loans . . 1,099,999 Bedford. Branch from Black- 1845 15f 125,000 wall Line . . . 1852 Besides powers for new Lines, viz.: Northampton & Mar- ket Harhorough 1853 18* Estimate . . . . 250,000 St. Alban’s . . . . 1853 7* Ditto . . . . 70,000 Shrewsbury & Crewe. 1853 33 Ditto . . . . 350,000 Total length in ope- Total ShareCapital. 25,049,592 ration, 1854 . 553* Debenture Debt . 9,993,448 Deb. 3* p. c. Stock 402,830 Grand Total . . 35,445,870 Newcastle and Carlisle 1829 78* Capital . . . . 1,749,386 Branch to Alston . Do. to Swalwell . 360 1AI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, and Branches. ot Acts. of each portion. Length. Estimate, Cost, or Capital. Miles. Miles. £. West Hartlepool. Incorporation of the Stockton & Hartlepool 1842 8 Clarence. Hartlepool West Har- 1829 37 45 hour and Dock Co. Total Capital . . 1,465,037 Dublin and Kingston (Ireland).... 1831 6 Extension to Dalkey . 1 3 Total Capital . . 290,000 Extension to Bray. . Hartlepool (leased to 1846 » 2 York, Newcastle, and Berwick. 1832 16 Capital authorized . 531,400 London and Greenwich . London and S.-Western 1833 3| 993,000 London & Southampt. Southampt. & Dorchr. Branches to Hampton 1834 76f 2,100,000 Court, Chertsey, Guildford, Farn- ham, Alton; to Lon- don, Brighton, and S. Coast Railway . Windsor, Staines, and South-western . . 267 Total Capital . . 8,856,484 North Union (1831, 22} miles), vested in Lon¬ don and N.-western, and including the Wi¬ gan and Preston and Wigan Branch . . . 1834 42 739,201 Great Western. London to Bristol. 1835 118} Slough to Windsor . Branch from Reading 3 to Basingstoke . . Branch from Reading 15} to Hungerford • 25} Branch from Didcot to Oxford. . . . Branch from Oxford 10 to Fenny Compton and Birmingham 65f Branch from Swindon to Gloucester . With branch to Ciren- 37 ' cester . Branch from Glouces- 4 ter to Cheltenham n < RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, of of each Estimate, Cost, or Capital. and Branches. Acts. portion. Gt. Western, continued. Miles. Miles. Branch from Chippen- ham to Westbury, Frome, and War¬ minster . 234 Branch from Glouces- ter to Grange-Court (Dean Forest) . . H Total mileage now in operation, including the two Shrewsbury lines (77 miles) . . 419 Tot. authorized Cap. 23,927,827 Llanelly Railway & Dock. Dock. 1828 Railwav. 1835 26 New Branches . . . n 33$ Authorized Capital 330,000 Arbroath and Forfar. . 1836 154 Capital .... 230,350 Bristol and Exeter . . 1836 75| Branch to Clevedon . 4 Do. Weston n Do. Yeovil . . 19 Do. Tiverton . Working (under lease) 5 105 Total Capital . . 3,535,794 also the Crediton line 6 miles, and the Somerset Central line 12 miles. Total worked by Bris- tol and Exeter Co. 123 miles. Dublin and Drogheda . 1836 31f Branch to Howth Transfer of Navan 3f 354 Blanch . . . . 1846 Total Capital . . 835,000 Dundee and Arbroath . Eastern Counties. 1836 16f 140,000. London to Colchester Northern and Eastern, 1836 51 from Stratford to Newport, with branch to Hertford 1836 44 Length of Eastern Counties proper 235 Norfolk line . . 964 Eastern Union . . . Total under the united 95 management of the three companies 4264 The same Union will work also the— 362 RAI RAILWAYS. RAI Name of Railway, Amal¬ gamation, Main Line, and Branches. Eastern Counties, con¬ tinued. Shepreth&Hitchin 18* Newmarket and Cambridge. .15 Newmarket&Bury 14* Harwich . . .12 Wisbeach Exten¬ sion . - . . .2* Hackney branch . 2\ East Anglian . 67 Tilbury ... 40 Beccles & Lowes¬ toft . . . . 5| Hull and Selby . . . Branch from Hull to Bridlington . . . (Rented to York & 1 North Midland) . J Date of Acts. Length of each portion. 1836 1845 Irish South-eastern. Amalgamation . . . 1846 of the Great Leinster and Munster from Carlow to Kilkenny|1836 and Kilkenny to Clon¬ mel . 1 1846 and of the Wexford, Carlow, and Dublin, 1846 Total length first au¬ thorized 89 miles, subsequently re¬ duced to . . . . London and Blackwall .[1836 Midland. 301 Amalgamation of the N. Midland from 1 Leeds to Derby . . MidlandCounties.from 1846 74* Derby to Rugby Birmingham & Derby, with fork line to London and North¬ 1836 58* western,at Hampton Total amalgamated length, 181* miles. The following lines are also incorporated:— Bristol and Gloucester, 1836 CO Total Length. Estimate, Cost, or Capital. Miles. 61 25 3 | £. Exp. to June, 1854.10,471,071 f Capital on which J J York & North [ | Midland Co. f pays 10 p. c. J 700,000 Cap. to June, 1854 270,343 1,050,000 363 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. Midland, continued. Miles. IVIiles. and Birmingham and Gloucester . . 95i Sheffield & Rotherham Leicester & Swanning- 9i ton. 16 Leeds and Bradford . Total incorporated lines 345£ miles. The following exten- 43 * sions have been au¬ thorized and con¬ structed since the amalgamation :— Syston &Peterborougli Nottingham& Lincoln, 48J & Southwell branch Leicester and Swan- 36 nington Extension . 23i Erewash Valley . . Nottingham & Mans- 21* field. 12* Mansfield & Pinxton . Total new branches, 149 71 miles. Grand total length open North-Eastern. 494i Total Capital . . 18,685,299 Co prising the— York, Newcastle, and Berwick. Main line . . 151 Coal branches in Berwick & Durham . . 99| Branches to Ain- wick, & Wark- worth,&Kelso 35 Branches in Yorkshire . 44^ 330 Computed Capital . 6,133,000 York & North Midland Main line, York, 1836 Normanton, & Knottingley . 26| BranchestoScar- borough and Whitby . . 53 Hull to Leeds . 50| Short branches. 133 ' -- 263 5,627,06 364 | IAI RAILWAYS. RAI 1 Name of Railway, Amal- Date Length Estimate, Cost, or Capital. gamation, Main Line, of of each Length. and Branches. Acts. portion. Sf.-Eastern, continued. Miles. Miles. £. Leeds Northern . . Main line, Leeds to Stockton . 61 Branches . . 9 1845 70 663 Computed Capital . 741,111 Computed Capital . 12,501,171 Sheffield, Rotherham, Barnsley, Wake¬ field, Huddersfield, and Goole. Sheffield & Rotherham Leased to Lancashire 1836 'Si 268,798 and Yorkshire Co. for £13,000 pr.ann. South-Eastern. South-Eastern original line from Redhill to near Dover . . 1836 66 London & Croydon . 1835 8f Extension into Dover 1843 Branch to Maidstone 1843 Bricklayers’ Arms br. Canterbury, Ramsgate, 1843 & Margate Extens. Folkestone branch and 1844 Harbour . . . . 1844 Tunbridge Wells br. . Gravesend and Ro- 1845 Chester branches . Minster & Deal, Ash- 1845 ford & Hastings brs. Branches from Rye to 1845 Rye Harbour, Tun¬ bridge Wells to Hastings, & “ North Kent ” br. from the junction with the London and Green¬ wich to Gravesend. ExtensiontoRoches- ter, over Canal. . 1846 Amalgamation of the Reading, Guildford, & Reigate, the Whit- stable & Greenwich, & Coal branch at Charlton to Thames 1852 Total length . . 289f Total Capital . . 10,903,892 RAI RAILWAYS. RA Name of Railway, Amal- Date Length gamation, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. Miles. Miles. JZ. Taff Vale. 1836 31-f Leased in perpetuity, the Aberdare . . Junction line with S. 1845 8* 66,600 Wales at Cardiff . Rhondda Valleys brs. 1852 12 are completing. Thames Haven . . . 1836 Renewed . . . . Railway from Eastern 1846 Counties line at Romford to Docks at Shell Haven . . 16 300,000 Partly abandoned, in favour of the Lond. Tilbury, & Southend 1853 Ulster. Belfast to Armagh West London. 1836 36 719,590 Incorporated underthe title of Birmingham, Bristol, and Thames Junction . . . . 1836 9* 294,887 Lancaster and Preston Junctions . . . 1837 20i United Capital . . 567,772 London, Brighton, and South Coast. Amalgamation, 1846, of the Croydon and Brighton Cos., viz. 741,000 London and Croydon 1835 84 London and Brighton Branches to Mitcham, Epsom, Eastbourne, Hailsham,Horsham, Lewes, Newhaven, St. Leonards, Hast- 1837 44 2,400,000 ings. Worthing, Arundel, Chiches¬ ter, & Portsmouth. Crystal Palace branch (opened June,1854) Total length produc- ing revenue (of which 7| miles be- long to the South¬ eastern, and 4| are held jointly with the South-western) 174 Total Capital . . 7,618,626 366 AT RAILWAYS. RAI 1 Name of Railway, Araal- Date Length gamation, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. B. & S. C., continued. United lines in con- Miles. Miles. £. templation. 1 Wimbledon and Crov- don (from Croydon to Mitcham) Act . 1853 2! E. Grinstead agreed to 1853 7 Bognor do . . 1853 6 240,000 Jarvport and Carlisle . 1837 28 Exp. to Dec. 1853 . 458,179 Edinburgh and Glasgow Leasing the Stirling 1838 46 1,200,000 and Dunfermline . Polkemmet branch. Cowlairs do. 21 Bathgate do. Campsie do. Ilf Total Capital . . 3,290,849 Ardrossan . 1840 12i Cost (to 1849) . . 100,950 Amalgamated with Glasgow and South¬ western . . . . 1854 Norfolk. Amalgamation (1845) of the Yar¬ mouth and Norwich 1842 20i Norwich and Brandon Wymondham and 1844 27J Dereham . . . Hi Dereham & Fakenham Branch to Ilalesworth 12i and Lowestoft . . 9i coItH o 00 Total Capital . . 2,221,163 South Wales Mineral . 1843 12* Authorized Capital 113,000 Chester and Holyhead . 1844 85 Including the Mold branch (from Ches¬ ter to Mold) . . 1847 134 Bangor and Carnarvon From Chester & Holy- 1851 7 head Railway, near Bangor, to Carnar¬ von, with a branch to port of Dinorwie 105i 4,289,270 Colchester and Stour Valley. Leased to E. Union . East Lancashire. Amalgamation (1846) of the Manchester, Capital Shares . . 300,000 Bury, & Rossendale 1844 14 „ Loans . . 100,000 Extension Act . . . 1846 10 Additional Shares . 530,000 „ Loans . 277,931 367 RAI RAILWAYS. RA Name of Railway, Amal- Date Length gamation, Main Line, of of each Total Estimate, Cost, or Capital. and Branches. Acts. portion. Length. E. Lancashire, continued. Miles. Miles. £. Extension Act . . . 1847 6 Additional Shares . 300,00C (Besides branches). „ Loans . 100,OOf | Blackburn & Preston 1844 n Authorized Shares. 120,00( | „ Loans . 40,00t Branches authorized . 1847 6 Additional Shares . 30,00(| ,, Loans . 10,000 Blackburn, Burnley, 1845 Accrington, & Colne Extension, with a branch eastward through Burnley to Colne, and Liverpool, Ormskirk, and Preston . . . Total length autho- 1846 36# rized (to June 30, 1854, 81|- miles were in operation) . 88 Exp. to June, 1854 3,869,004 Eastern Union. Amalgamation, 1847, of the E. Union 1844 18 (From Colchester to Ipswich). Ipswich and Bury . . Extension fromHaugh- 1846 27 ley to Norwich . . 4 Trowse br. opened 1852 2 (Connecting the Ipswich and Bury with the E. Union.) Hadleigh branch . . 7 Sudbury branch . . Total length autho- 12 rized about . . . 95 Ord. Share Capital. 1,206,900 Under the manage¬ ment of theE.Coun- ties (which see). Great Southern and Capital—Shares . 3,602,381 Western . . . . From Dublin to Cork, 1844 Loans 410,606 ! passing near Portar- lington, Thurles, Tipperary, and Mal¬ low, with a branch to Carlow. North British . . . . 1844 62 From Edinburgh to Berwick (junction with York, New- 368 f M RAILWAYS. RAT Jame of Railway, Amal- Date Len gth carnation, Main Line, of of each Length. Estimate, Cost, or Capital. « and Branches. Acts. portion. . British, continued. Miles. Miles. £. castle, & Berwick), with branch to Had- dington. Edinburgh & Dalkeith purchased . . . 1845 14 Br. to connect same . Edinburgh & Hawick 1845 2 (powers transferred) Branches to Selkirk, 1845 43* Jedburgh, Kelso, Tranent, Cockenzie, North-Berwdck, and Dunse . 1846 42 ■ Deviation and short extension. . . . Total length autho- 1847 rized, of which 149 miles are now open 163 Lancaster and Carlisle . 1844 70 Capital, . . . . 1,613,903 1 Vhitehaven Junction . Shrewsbury and Chester; 1844 12 Shares and Loans . 181,196 or N. Wales Mineral from Chester to Wrexham. 1844 Extended to Ruabon . Branches to Coal and 1845 Mineral Works, nr. Wrexham . . . 1846 Total about . . . . south Devon . 1844 25 From Exeter to Ply- mouth. Branches to Torquay and other places Extension into Tor- 1846 quay & to Brixham 1847 Total length authorized Aberdeen . 1845 70 Capital . . . . 2,101,564 From Guthrie (Ar- broath and Forfar) to Aberdeen, with branches to Brechin and Montrose. Total length,including leased line . . . 72 Total Capital . 1,760,932 Belfast and Ballymena . 1845 With branches to Car- rickfergus and Ran- dalstown . . . 38 Capital . . . . 385,000 369 RAI RAILWAYS. RA Name of Railway, Amal- Date Length 1 gamation, Main Line, of of each Length Estimate, Cost, or Capital. and Branches. Acts. portion. Belfast& Ballymena, cont. Miles. Miles. £. Extension from Ran- dalstown, through Troome, Castle Dawson, Maghera- felt, & Moneymore to Cookstown . . 1853 27 Estimate . . . . 192,50*' Blackburn. Amalgamation, 1846, of Blackburn, Darwen, and Bolton and Blackburn, Clitheroe, 1845 and N. W. Junction Total length auth d . . Caledonian. 1845 47 Carlisle to Carstairs . 73! Carstairs to Edinburgh 26| Carstairs to Glasgow . Cockermouth and Work- 31| Total Capital . 7,877,411 ington . . . . Branch from Marron 1845 H Foot to Bridgefoot. 1849 l_ Cork and Bandon. 1845 Deviation & Extension into Cork . . . 1848 20 Dublin&Belfast Junction 1845 56 Capital . . . . 1,042,3650 Dundalk and Enniskillen 1845 Original Capital. Shares . . 750,000 Loans . 250,030| East Anglian. Incorporation, 1847, of the Lynn and Elv, with branch to Wisbeach 1845 36! Lynn and Dereham 1845 26! Ely and Huntingdon . 1845 22f Capital . . . . 1,329,745 Furness. 1844 Ilf Total length (of which ; 20 are in operation) 22 Capital . . . . 396,841 Kendal and Windermere 1845 lOf Capital . . . 215,519 From the Lancaster and Carlisle at Oxen- holme to Birth waite, near Windermere Lake. 1845 Leeds Northern Extended to junction with the Stockton and Hartlepool . . 1846 370 371 RAI RAILWAYS. RA Name of Railway, Amal- Date Length gamation, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion St. Helen’s. Miles. M iles. £. Amalgamation of the Sankey Brook Na¬ vigation, and St. Helen’s & Runcorn Gap Railway Branch from the ori- 1845 ginal line atWidness to Garston, 4 miles south of Liverpool; and Docks at Gars- ton. 1846 n Branches to -Warring¬ ton and Blackbrook Branches to Rainford 1847 4* junction, and to the Eccleston Coal Fields, and minor branches . . . . 1853 Total Capital . . 881,131 Scottish Central . . . 1845 Powers to construct branches to Tilli- coultry, Denny, and Crieff, and minor branches ending at Perth. 1846 Total length authoriz- ed (of which 50J miles are opened) . 62 Capital. Consolidated Stock 1,020,000 Preference Shares 151,5421 Scottish Midland Junct. 1845 Perth to Forfar . . 32i Branch to Newtvle . Branch from Coupar 2 Angus to Blair¬ gowrie . . . . 1853 4a Branch from Drum- gley to Kirriemuir. 1853 41f Capital . . . . 711,230 S South Wales . . . . 1845 From Fishguard Bay, Pembroke, and run¬ ning thence along the northern shore of the Bristol Chan- nel, through Car¬ marthen, Llanelly, Swansea, Neath, Cardiff, and New- 372 AI RAILWAYS. RAT Name of Railway, Amal¬ gamation, Main Line, and Branches. oath Wales, continued. port, to the west bank of the River Wye at Chepstow, with branch from Newport to Mon¬ mouth. Leased to Gt. West, in 1851 Length authorized . Swansea to Chepstow, opened June, 1851 Grange Court to Chep stow, East, opened 19th Sept. 1851 Swansea to Carmar then, opened 11th Oct. 1852 . . Carmarthen to Haver fordwest, opened Jan. 1854 . Forest of Dean, con verted from Tram¬ way, July 1854 . Total length opened —1635 miles . Extension of Pem broke line, & branch to Swansea Harbour and Junction with Newport and Ponty* pool.1853 Waterford & Kilkenny . 1845 From Waterford to Kilkenny .... with branch to Kells Total length autho¬ rized . (of which, main line 31 miles are in operation.) Waterford & Limerick . 1845 Including branches Wear Valley. Whitehaven & Furness .1845 From Whitehaven to a junction with the “ Whitehaven junc¬ tion” at Whiteha¬ ven, and a junction with the Furness Date of Acts. Length of each portion, Miles. 75 m 301 31 31 61 Total length. Miles, Estimate, Cost, or Capital. 169 37j 75 Total capital. Shares . . 2,444,250 Loans, etc. . . . 1,423,997 Estimated cost . . 170,000 Power to borrow . 56,600 Shares & Loans Capital 599,000 1,132,538 373 R f RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, and Branches. of Acts. of eacli portion length. Estimate, Cost, or Capital. Whitehaven, continued. ! Miles. Miles. at Foxwell, near Broughton. 35 Total length . . . Branch to harbour Ambergate, Nottingham 1853 3 ¥ Capital authorized . 469,933 and Boston, and E. Junction . . . . 1846 1 (Originally 90 miles but reduced to . . viz.: from Grant¬ ham to Colvvick.) 23 Total Capital . . 760,025 Belfast & County Down 1846 Average cost per mile, £15,520. Buckinghamshire. (Leased to London andNorth-western), Amalgamation 1847 of the Buckingham and Brockley . . 1846 and the Oxford and Bletchley . . . Extension, north to 1846 31* Banbury. Line from Claydon to a junc¬ tion with the Great Western, Oxford, & Rugby line, at Ban¬ bury . 21* 53 Shares and Loans . 1,659,600 Caledonian and Dumbar- tonshire Junction . 1846 Total in operation . Cork, Blackrock, and Si Capital Expended . 239,664 Passage . . . . Cork to Passage West Extension to Monk- 1846 6* stone Baths (Main line open. Extension in abeyance) . . 1* Cornwall. 1846 In connectionwith the South Devon at Ply¬ mouth,to Falmouth, with branches to Padstow, to the Lis- keard and Caradoc, * and to the quays at Truro and Penryn 83 Expen. to Dec. 1853 540 012 Works in Progress. 374 1AI RAILWAYS. RAI Name of Railway, Amal- Date Length Total length. gamation. Main line, and Branches. of Acts. of each portion. Estimate, Cost or Capital. Deeside. Originally in- Miles. Miles. £. corporated . . . 1846 Re-incorporated . . Dublin and Wicklow, in- 1852 16} Capital authorized . 141,650 corporated, as Water¬ ford, Wexford, Wick- low, & Dublin . . Title altered & length 1846 135} Reduced Capital 500,000 etc. reduced. . . 1851 Dundee & Perth, and Capital. Shares . . 570,000 Aberdeen Junction . General Terminus and 1847 21f Debentures 216,600 Glasgow Harbour . . Gloucester and Dean 1846 5 Forest . . . . 1846 16 Capital . . . . 279,000 Leased to Gt. Western 1854 Great North of Scotland 1846 138} Capital . . . . 518 232 4 0 miles between Aber- deen and Huntley completed 19 Sept., 1854. 1846 Great Northern . . . 1846 London to Askern,near York. Total powers for 335} miles, of which 181 are abandoned, leav¬ ing a total of . . 154} Total Capital . . 11,128,025 Killarney Junction . . 1846 41 Capital . . . . 247,932 Worked by the Great Southern & Western Malton & Driffield June. 1846 24 Capital . . . . 287,014 Amalgamated with North-eastern. Manchester, Buxton, Capital. Shares. . 453,750 Matlock, & Mid. Jn. (From Ambergate to 1846 Loans . . 151,250 Rowsley). . . . Worked by Midland Manchester, Sheffield, & Lincolnshire Amal¬ gamation . . . 1846 Of the Sheffield, Ash- ton-under-Lyne, & Manchester; the Great Grimsby and Sheffield Junction; the Sheffield and Lincolnshire; the Sheffield and Lin- R 2 I 375 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, of ot each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. Manchester, continued. Miles. Miles. £. colnshire Extension, and the GreatGrims- by Dock Companies; and (in 1847) of the Manchester and Lincoln Union . . 171f Total Capital . . 8,137,451 Morayshire (from Stot- field to Elgin) . 1846 m Capital .... 41,616 Newmarket. From Clies- terford Junct. (Eas¬ tern Counties) to Newmarket, etc. . 1846 23 Branch to Bury St. E dmunds single line 14 37 Newport, Abergavenny, and Hereford . . Branch to the Tall 1846 33 Vale line . . . . Powers to make devia- 1847 16 Capital .... 628,245 tions & short bran. 1853 Newrv, Warrenpoint, & Rostrevor . . . 1846 8* Capital .... 135,976 North London . . . 1846 n late East and West India Docks, and Birmingham Junct. Branch to Blackwall Extension near Bow 1850 Total Capital . . 1,198,661 North Staffordshire . . 1845 Total Capital . . 5,820,000 Length of Railway . 123 (besides 110 miles of canal.) North-western ... . 1846 Capital .... 1,159,754 Rovston and Hitchin 1846 12i Capital .... 800,000 Extension to Bedford 1848 5 Works cost per mile 3,500 (leased to G. Nor.) Shrewsbury & Birming- ham with branches to Madeley & Iron- bridge . . . . 1846 29^ Capital .... 1,344,787 Amalgamated with Great Western. Shrewsbury & Hereford 1846 Capital .... 600,000 South Staffordshire . . 1846 Amalgamation of the South Staffordshire, junction; and the Trent Valley, Mid¬ land, and Grand 37G IAI RAILAVAYS. RAI Name of Railway, Amal- )ate Length gamation, Main Line, of of each Estimate, Cost, or Capital. and Branches. 4cts. portion. S. Staffordshire, contin. Miles. Miles. Junction; besides branches .... Capital authorized . 1,260,000 Vale of Neath. . . . 1846 Line from Neath to Merthyr Tydvil. with branches to the Aberdare, etc. 33 Total Capital . . 712,983 West Cornwall . . . 1846 From Carredas to Pen- zance, with branch to the Cornwall line Length open . . . Birkenhead, Lancashire, 25 Capital . . . 459,253 & Cheshire Junct. Chester and Birken- 1847 head amalgamated 1847 Re-incorporated 1852 Total Capital . . 2,323,319 Glasgow and S.-Western Amalgamation (1850) of the Glasgow, Paisley, Kilmarnock and Ayr; and the Glasgow, Dumfries, and Carlisle . . . ' 171f Total Capital . . 4,090,000 Lancashire & Yorkshire. 1847 Amalgamation of the Manchester&Leeds; the Manchester,Bol¬ ton and Bury; the Li¬ verpool and Bury; the Huddersfield and Sheffield; theWake- field, Pontefract, &. Goole, and the West Riding Union . . 253^ Total Capital . . 12,308,442 Liverpool, Crosbv, and Southport . . . 1847 m Capital . . . . 300,000 Manchester & Southport 1847 Capital authorized . 1,033,300 South Yorkshire . . . Branches to Elescar & 1847 Worsbro’ . . . 1850 Capital .... 1,085,787 Bangor and Carnarvon. Amalgamated with Chester & Holyhead East Suffolk.Incorp as the Halesworth Beccles,& Haddiscoe 1851 7 Worked iointly with 1851 I jCapital Shares . the Norfolk by Ac! 1857 450,000 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamatkm, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. East Suffolk, continued. Miles. Miles. £. Main line . . . . 24 34f Loans . 150,000 Branches . . . . Edinburgh, Perth, and 10 J Dundee. Re-incorporation . . Total length authord. 1851 90f Total capital . . 3,161,263 Length opened 71 f m. Hereford, Ross, & Glou- Capital .... 274,073 cester . 1851 23 North & South-western Junction . . . . 1851 3| Capital .... 83,810 St. Andrew’s . . . . 1851 4* Capital .... 25,000 Ulverstone & Lancaster. Warrington & Stockport 1851 19 Capital .... 293,333 (late Warrington & Altrincham Junct.) 1851 14 Capital . . . . 256,000 Waterford and Tramore Waveney Valley (Tivets- 1851 17* Capital . . . . 56,343 hall to Bungay) . Authorized extension 1851 13* to the East Suffolk. 1853 6 19* Authorized Capital. 155,699 Blyth and Tyne . . . 1852 13 Branches . . . . Leeds, Bradford, and 1853 8f 21f Halifax Junction . 1852 Branches to Ardsley and Gildersome, etc. (Worued by G. N.) 1853 7 Capital .... 241,063 Leven ...... London, Tilbury, and Southend . . . 1852 6 1852 40 Capital (Computed) 500,000 (Worked by E. C.) J Londonderry and Cole- raine. Re-incorp. . 1852 37 Total Capital . . 565,000 J Londonderry and Ennis- killen. Re-incorp. 1852 60 Total Capital . . 590,849 Middlesbrough and Guis- borough . . . . 1852 9 Br. to Cleveland Hills 1852 3 12 Capital . . . . 73,078 Somerset Central . . . 1852 12* Capital .... 81,911 In course of construe- tion, 1854. Ballymena, Ballymoney, Coleraine and Por- trush Junction . . 1853 35 Estimate per mile . 4,000 Banbridge, Newry, Dub- lin, & Belfast June. 1853 6f Estimate .... 35,000 BedaleandLeyburn . . 1853 Hf Do. .... . 44,000 Bideford Extension . . 1853 6 Do. 48,00q 378 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length gamation, Main Line, of of each Length. Estimate, Cost, or Capital. and Branches. Acts. portion. Miles. Miles . £. Bognor . Boston, Sleaford, and 1853 54 Estimate - . - 27,000 Midland Counties . 1853 27} Do. ... . . 200,000 Chard. Colefard, Monmouth, 1853 Usk, and Pontypool 1853 22 Do. 160,000 Crieff Junction . . . Darenth Valley (From 1853 8f Do ... . 45,000 Dartford to Farn- ingham) . . . . 1853 5f Do. 40,000 East Grinstead . . . East Kent (Strood to 1853 64 Do. .... 47,000 Canterbury) . . . 1853 314 Do. . 437,837 Forth and Clide Junct. . 1853 29* Do. 150,000 ! Hampstead Junction 1853 6f Do. .... . 250,000 (Projected as North and South-western, Hampstead, & City Junction.) , Hull and Holderness 1853 184 Do. ... . 110,000 Limerick and Ennis . . 1853 244 Do. ... . 150,000 Limerick and Foynes 1853 264 Do. 130,000 Llanidloes and Newtown Londonderry, Enniskil- 1853 12} Do. 66,000 len, and Sligo . . 1853 514 Do. . 297,000 Londonderry and Lough Swilly. . . . ; 1853 9-4 Do. . . . . 39,000 • Metropol. Subterranean 1853 4 Paddington to Gen. Capital. Shares . 1,000,000 Post Office . . . Loans . 333,000 Norwich and Spalding . 1853 154 Branch to Wisbeach 1853 10 254 Estimate . . . . 170,000 Peebles. From Hawick branch of North British to Peebles . 1853 18* Capital . . . 93,000 Port Carlisle. (Converted canal). 1853 114 Do. .... 194,477 Portsmouth. Goldaming Station of South - western to Havant Junction with London and Brighton line, and the Fareham Exten¬ sion of London and South-western and direct to Portsmth. 1853 32} Estimate . . . . 350,000 Roscrea & Parsonstown Junction . . . . 11823 224 Do. 100,000 379 RAI RAILWAYS. RAI Name of Railway, Amal- Date Length Total gamation, Main Line, of of each Estimate, Cost, or Capital. and Branches. Acts. potion. Miles. Miles. £. St. Ives and West Corn- wall Junction . . 1853 4 Estimate . . # 32,000 Severn Valley . . . . 1853 m Do. . . . 560,000 Staines, Workingham, & Woking Junction . 1853 22f Do. . . . 270,000 Stamford and Essendine 1853 3f Do. . . . 46,500 Wellington & Severn Jn. 1853 6 Do. . . . 60,000 West of London and Crystal Palace . . 1853 9f Do. . . . 360,000 Wimbledon & Croydon . 1853 5* Do. . . . 45,000 Worcester & Hereford . 1853 301 Do. . . . 560,000 Ayr and Maybole . . . 1854 5 JL °8 Capital . . . 43,000 Bagenalstown and Wex- ford . . . . . 1854 m Estimate . . 270,000 Border Counties . . . 1854 26 Do. . . . 200,000 Hexham to Palstone. Bradford, Wakefield, & Leeds . . . . . 1854 91 Do. . . . 180,000 Carmarthen & Cardigan 1854 251 Do. . . . 247,700 Caterham. To Brighton line . . . . . 1854 4f Do. . . . 30,000 Chipping Norton . . . 1854 41 Do. . . . 24,000 Cork and Youghal . . 1854 Capital . . .. . 500,000 Darlington and Barnard Castle. 1854 151 Estimate . . 100,000 Dowlais. 1854 1 ■5 Do. . . . 7,500 Hertford and Welwyn . 1854 73 i 4 Do. . . . 47,078 Horncastle & Kirkstead 1845 Do. . . . 45,000 Inverness and Nairn 1854 15f Do. . . '. 80,000 Leominster and Kington 1854 131 Do. . . . 106,000 Mallow and Fermoy . . 1854 16f Capital . . 133,000 N. York, and Cleveland. 1854 291 Estimate . . 180,000 Perth and Dunkeld . . 1854 81 Do. . . . 70,000 Potteries, Biddulph, and Congleton . . 1854 181 Do. . . . 190,000 Rhymney . . . . . 1854 12 Capital . . 139,000 Salisbury and Yeovil . 1854 401 Do. . . . 533,333 Selkirk and Galashiels . 1854 51 Do. . . . 32,000 Shropshire Union , . 1854 Do. . . . 2,255,638 Leased to L. & N. W. South Devon &Tavistock 1854 171 Estimate . . 154,000 Stockport, Disley and Wharley-bridge 1854 10 Do. . . . 150,000 Tralee and Killarney 1854 22 Do. . . . 110,000 Vale of Towy .... 1854 HI Capital . . 78,000 Wells and Fakenham 1854 Do, . . . 93,000 Westminster Terminus . 1854 2| Do. . . . 640,000 Whitehaven, Cleator & Egremont . . . 1854 6il Estimate . . • • 48,000 380 RAIN-GAUGE. RAI Railway chairs, the pieces of cast- iron which fix the rails to the sleepers. Rainbow, a meteor in the form of a party-coloured arch or semicircle exhibited in a rainy sky, opposite to the sun, and caused by the refraction of his rays in the drops of falling rain: it never appears greater than a semicircle, but often much less: it is always double, there being what is termed the superior and inferior, or primary and secondary rainbow: they al¬ ways exhibit the seven prismatic colours; and the whole of this phenomenon depends upon the rays of the sun falling on spheri¬ cal drops of water, and being in their passage through them re¬ fracted and reflected. Rain-gauge, an instrument for mea¬ suring the depth of rain that falls. A very simple and excellent instru¬ ment for this purpose is shown in fig. 1. It consists of a copper Fig. i. funnel, from 5 to 7 inches diame¬ ter. The rain being collected in a glass bottle, this bottle should be placed in a small stand near the surface of the ground, to protect the bottle from the action of the RAI sun. The amount of rain fallen in a given time is measured in a graduated glass jar, one-tenth the area of the funnel, similar to that shown in the figure, and so divided that every inch in depth of the tube shall indicate one-tenth of an inch falling in the funnel. The amount of rain falling can be mea- I sured by such an instrument to | soVi 0 th P art of an inch, or even | less. An instrument, fig. 2, is also used for measuring the fall of rain. It consists of a cylinder of copper or other metal, from 5 to 7 inches in diameter, and 30 inches long. A float, just so much smaller as to allow it to rise freely when it becomes filled with water, is placed within the cylinder, and to the centre of the float is attached an j upright staff, marked in inches and | tenths of an inch, which, rising j through a hole at the bottom of | Fig. 2. the funnel, as shown in the figure, indicates the depth of rain received into the gauge. This instrument is very simple, and shows the amount of rain col¬ lected upon mere inspection: it 381 RAI RATCHET. REC has, however, been proved that in hilly districts and exposed situa¬ tions, when the staff rises but a small distance above the receiving surface of the gauge, owing to the rain being carried along with the wind in a slanting, and frequently, on the tops of high hills, almost in a horizontal direction, that the staff, though of small diameter, arrests a large amount of rain, which runs down the staff and causes a much larger quantity to be collected than is properly due to the rain-fall. (Some interesting experiments, showing the incor¬ rect results given by these rain- gauges, will be found in a ‘ Report on the Supply of Surplus Water to Manchester, Salford, and Stock- port,’ by S. C. Homersham, Civil Engineer.) When these kind of rain-gauges are used, the rod should be movable, fitting loosely the socket or the float, and only placed in the gauge when the depth of the rain-fall is to be ascertained. Rainline, a small rope, or line, some¬ times used to form the sheer of a ship, and to set the beams of the deck fair. Rake, in mining, an oblique vein. Rake, in ship-building, an obtuse angle, such as the stem and stern- posts make with the keel of a ship. Rake of a ship, all that part of the hull which hangs over both ends of the keel. Raking moulding, in joinery, a mould¬ ing whose arrises are inclined to the horizon in any given angle. Ramp, in hand-railing, a concavity on the upper side, formed over risers, or over half or quarter span, by a sudden rise of the steps above, which frequently occasions a knee above the ramp. Rampant, in heraldry, a term applied to a lion, leopard, etc., standing on his hind legs, in the escutcheon, with his forefeet reared up in the posture of clawing. Rampant Arch, one whose abutments spring from an inclined plane. Ranges, pieces fixed to the inside of a ship to belay the ropes; and sometimes expressed for those be¬ tween the ports whereon the shots lie. Rasp, a rough file. Ratchell, loose stones. Ratchet-hr ace, a tool for drilling a hole in a narrow plane where there is not sufficient room to use the common brace: a ratchet-wheel is fixed on the drill-socket, and turned by a handle with a strong spring attached to force round the socket on the forward motion, and slips over the teeth on the backward motion. Ratio is the relation of two quanti¬ ties of the same kind with respect to quality, and is divided into arithmetical and geometrical. Ratlines, in ship-rigging, small lines that traverse the shrouds of a ship horizontally, at regular distances, and form ascending ladders to the mast-head. Rebate, a deep groove, or channel, cut longitudinally in a piece of timber to receive the edge of a plank, or the ends of a number of planks, which are to be securely fastened in it. Receiver of an air-pump, in pneu¬ matics, a glass vessel placed on the top of a plate, out of which the air is exhausted by the pump. Recess, a cavity in a wall, left either for ornament or use when it is to receive some furniture, as a side¬ board, or to add to the quantity of room; and for ornament when made in the form of a niche, to give beauty and variety to the building. Reckoning, in navigation, the compu¬ tation of a ship’s way (usually by the log), or the act of estimating the distance run between one part and another. Reconciles, or Top Timber-Hollow, in ship-building, a mould sometimes used to form the hollow in the top- 382 REC RED-LEAD. REF side, which is tailed the reconciling mould. Rectangle, a right angle made by the falling of one line perpendicularly upon another. Rectification, in chemistry, is the repetition of a distillation or a sublimation several times, in order to render the substance purer and finer, or freer from earthy and aque¬ ous particles. Rectification, in geometry, is the finding of a right line equal to a proposed curve. Rectilineal, or Rectilinear, consisting of right lines. Rectory, a house for the residence of the rector of a parish, usually situ¬ ated near the church. Red is the second and intermediate of the primary colours, standing between yellow and blue, and in like intermediate relation also to white and black, or light and shade. Hence it is pre-eminent among colours, as well as the most positive of all, forming with yellow the secondary orange and its near relatives, scarlet, etc.; and with blue the secondary purple and its allies, crimson, etc. It gives some degree of warmth to all colours, but most so to those which partake of yellow. Red-lead, Minium, or Saturnine red, an ancient pigment, by some old writers confounded with cinnabar, and called Sinoper, or Synoper, is a deutoxide of lead, prepared by subjecting massicot to the heat of a furnace with an expanded sur¬ face and free accession of air. It is of a scarlet colour and fine hue, warmer than common vermilion ; bright, but not so vivid as the bin- iodide of mercury, though it has the body and opacity of both these pigments, and has been confounded even in name with vermilion, with which it was formerly customary to mix it. When pure and alone, light does not affect its colour; but white-lead, or any oxide or prepa¬ ration of that metal mixed with it, soon deprives it of colour, as acids do also; and impure air will blacken and ultimately metallize it. Red Ochre is a name proper rather to a class than to an individual pig¬ ment, and comprehends Indian red, light red, Venetian red, scarlet ochre, Indian ochre, redding, rud¬ dle, bole, as well as other absurd appellations, such as English ver¬ milion, and Spanish brown, or majolica. Reef, in navigation, to contract a sail by tying up a portion of it to the yard. Refectory, a refreshment-room ; the hall or apartment in a monastery. Refining and Puddling of Iron. The chemical difference between cast- iron and wrought-iron consists principally in the difference of de¬ gree in which foreign matters are present in each, which is in larger amount in the former than in the latter. There ,are many cases in which wrought-iron contains a larger amount of impurities than cast-iron, and is yet malleable; while cast-iron of the same com¬ position may be very hard and brittle. Berzelius detected in a certain kind of bar-iron, 18 per cent, of silex; and yet this iron was still malleable and useful. One-tenth of that amount of silex will make cast-iron brittle. The foreign matters generally combined with pig-iron are carbon, silicon, silex, sulphur, phosphorus, arsenic, zinc, manganese, titanium, chrome, aluminium, magnesium, and cal¬ cium. Each of these tends to make iron brittle; therefore, in converting cast into wrought iron, it is necessary, as far as possible, to remove them. Carbon and other foreign matters divide the crude iron into two very distinct classes. In the one, carbon is only an acci¬ dental mechanical admixture; in the other, it is in definite chemical combination. To the first belong the white iron of heavy burden, 183 REF REFRACTION. REF and grey iron ; to the latter, the white iron of small burden, or very fusible ores. From the behaviour of the different metals in the refin¬ ing and puddling process, the pre¬ sence of silicon and silex appears to exert a similar influence: it is not possible to remove silex from white metal with which carbon is chemically combined. The silex is present in the form of silicon. White metal of small burden may contain from 5 to nearly 6 per cent, of carbon ; and, if smelted from pure ore, almost an equal amount of other foreign matter, such as silicon. Upon the pre¬ sence and form of these its white colour and crystallization in a de¬ gree depend. Grey pig-iron seldom contains more than 4-75 per cent, of carbon, and generally only from 3‘50 to 4 per cent. When carbon is present to the amount of but 2 to 3 per cent., it becomes white. The more this iron is stretched, the more it forms fibres. Fibrous bar-iron resembles hickory wood, in the fact that it is a combination of fibres and spaces. In bar-iron, these spaces are filled with cinders, and that portion of the iron is proportional to the fineness of the fibres. That portion of the iron which is not melted, which crys¬ tallizes too fast, or whose prema¬ ture crystallization the workman cannot prevent, is in the condition of cast-metal, and cannot be con¬ verted into fibrous wrought-iron. In the puddling furnace it is ne¬ cessary to prevent crystallization by manual labour. This result, whether in the Catalan forge, the Woolfs oven, or the German forge, is partly accomplished by the blast. Reflection is the return or regressive motion of a movable body, arising from the reaction of some other body on which it impinges. Reflex, in painting, denotes those parts of a picture that are supposed to be illuminated by a light re¬ 384 fleeted from some other body re¬ presented in the piece. Reflux, in hydrography, the ebb, back¬ ward course of water, flux, or flow¬ ing of the sea. Refraction, in mechanics, the incur¬ vation or change of determination in the body moved. In dioptrics, it is the variation of a ray of light from that right line in which it would have passed on, had not the density of the medium turned it aside. It is the bending of a ray of light towards the perpendicular when it passes intoadensermedium, and from the perpendicular w hen it passes into a rarer medium. The law of refraction was first completely established by Snell and Descartes at the commencement of the seventeenth century. The first part of this law is similar to that of reflection, viz. that the angles of incidence and refraction (i. e. the angles which the incident and re¬ fracted ray each make with the per¬ pendicular or normal of the surface, or in this case the angles pc d and p' c d") are both in the same plane. Any ray meeting the surface of a new medium is split into two rays, one reflected and the other re¬ fracted ; as, for instance, the ray b c into the reflected ray c b', and the refracted ray c b"; or d c into the tw y o rays c d' and c d ". So also a ray b" c will be partly re¬ flected in the direction c b', and partly refracted into c b ; or d" c will be reflected into c d', and re¬ fracted into c n. Now in all these cases the three rays, incident, re¬ flected, and refracted, will be all in one plane, and that plane per¬ pendicular to the acting surface A A. The angles of incidence and re¬ flection (such asrcD and p c D f ) are, as already explained, invariably [ equal; but that of refraction (in this case p' c d") is different from both, but connected with them by this law, that (at the same surface) the sines of incidence and refraction REF REFRACTION. REF to the same radius hear a constant ratio to each other, which is always the same in the same two media. For instance, in passing through the surface aa, at whatever degree of obliquity, and whether upwards from the water into the air, or down from the air into the water, a ray ! is invariably so bent that the angle it makes with the perpendicular p p in the air may be greater than that in the water; and that the sine of the angle in air may be to that in water (to the same radius) as 4 to 3, which is the ratio that has been determined by experi- | raent. At the surface separating any other two media, a different | ratio would be observed with equal constancy. To find the new direction into which any ray, such as d c, will be bent by this surface, draw a circle round the point c with any radius, such as c s, and the sine of the ray in air (to this radius) will be found to be s s. Therefore the sine in water will be £ of s s. Draw a line parallel with c p at a distance there¬ from equal to £ of s s, viz. at the distance s' s", and as this intersects the circle at s", the refracted ray must pass through s" to make its sine in water (s' s") £ of its sine in air (s s), both to the same radius j (c s, or c s"). If any other radius be chosen, as c s, it is plain that the same result will be obtained; for, by the property of similar tri¬ angles, if s' s" be £ of s s, then s' s" is also £ of s s. In tracing the course of a ray upwards from the water, as d" c, then, having found its sine in water to any fixed radius, make its sine in air ^ greater, because the sine in air is always greater than that in water, as 4 : 3 ; and thus the new direction of the ray will be found to be c d. In this ease a very singular effect takes place if the ray be very oblique to the surface, as f c. It should be remarked that no ray passing from the air into the water, however obliquely, could ever be refracted into the direction c f, for this reason, the sine of no angle can be greater than the radius to which it is drawn, therefore no ray can have its sine to radius c s greater than c s. But its sine in water is only £ of that in air, and consequently cannot exceed £ of the radius. Now the sine of the ray c f, viz. f z, is more than £ of the radius c s, therefore no degree of obliquity of the ray in air will enable it to become so oblique in the water as c f. But a ray may ascend in the direction f c as well as in any other. Now its sine in air must become greater than f z ; but this is impossible, for a line £ longer than f z would be longer than the radius c s, and therefore too long to be the sine of any angle to that radius. As this ray, then, cannot be refracted according to the law, it is not refracted at all, but totally reflected in the direction c f the only known instance of to¬ tal reflection, for none of the light can penetrate the surface a a, which is, in fact, absolutely opaque to this light. This phenomenon of total reflection may be seen by looking through the side of a tumbler con¬ taining water up to its surface, in some such direction as /'c, when the surface will be seen to be 385 REFRACTION. REF opaque, and more reflective than any mirror, inasmuch as the images in it are perfectly equal in bright¬ ness to the objects themselves. Now at the surface between any other two media, the ratio of the sines would be different; for though all surfaces reflect alike (as re¬ gards the direction of the ray), all do not refract alike. Suppose the ray passed from vacuum into water, the ratio would be rather greater than 3 : 4, namely 1: 1‘335. In passing from vacuum into air of the common density, the refraction would be much less, and conse- quen tly he sines much more nearly equal, viz. as 1 : 1-000294. Now if the sine in any medium be called 1, the corresponding sine in vacuo is called the index of refraction of that medium ; and is specific for each substance, or as constant as its density, expansibility, specific heat, or any other measurable qua¬ lity. Thus the refractive index of air of the common density is 1-000294, that of water 1 335, of crown glass 1-52, of flint glass 1-55. In the case above considered, of refraction from air into water, and vice versa, the sines in air and in water are, strictly speaking, as 1 335 : 1-000294; andgenerallythe sines on each side of any surface are inversely as the refractive in¬ dices of the two media. # The refractive indices of a great many media have been measured and arranged in tables. When the density of any substance is in¬ creased or diminished, its refrac¬ tive power is increased or dimi¬ nished in the same ratio. The application of the laws of refraction accounts for numerous deceptive effects seen in the atmo¬ sphere, and included under the general term mirage ; the most fa¬ miliar of which is the distortion of objects seen through a rising cur¬ rent of hot air, which, from its smaller density, has a lower re¬ fractive power than the surround- REF ing cold air, and therefore bends the rays in various directions. It is also plain that the rays of the heavenly bodies coming from space into our atmosphere must be re¬ fracted, and thus cause the objects whence they come to appear rather above their true place, as the eye at d in the figure sees d in the direction d c rather above its true place. This forms one of the sources of error to be allowed for in all astronomical observations, and tables are calculated for finding its amount, depending on the ob¬ ject’s apparent altitude, and the state of the barometer and ther¬ mometer. Owing to the very small refractive power of air, however, this error is hardly sensible when the object is high, but increases rapidly towards the horizon, where it becomes 33', or rather more than the sun’s or moon’s diameter, so that these bodies may appear just clear of the horizon when they are really completely below it. As the density of the air diminishes gra¬ dually upwards, atmospheric re¬ fraction is not, like that which has been just considered, a sudden change of direction, but the ray actually describes a curve, being refracted more and more at every step ; and this applies equally to the light from a distant terrestrial object which is either lower or higher than the eye, because it must pass through air of constantly increasing or diminishing density. This refraction has therefore to be allowed for in levelling, which is done by assuming that the light from a distant object comes to us in a line arched or curved up¬ wards, the radius of which is about seven times that of the earth. The application of these laws of Dioptrics has also led to the un¬ derstanding of the mechanism of the eye, and hence to the imitation thereof by lenses, affording the re¬ medies for its infirmities of long and short sight, and disclosing the 386 REG REGULATORS. RET wonders of the telescope and the microscope. Regalia, in heraldry, ensigns of roy¬ alty ; the apparatus used at a co¬ ronation. Regardant, in heraldry, signifies look¬ ing behind, as applied to a lion or any other beast. Regatta, the name of an aquatic spec¬ tacle consisting of gondola races, etc., exhibited at Venice. Reglet, a flat, narrow moulding, em¬ ployed to separate panels or other members ; or to form knots, frets, and similar ornaments. Regula, a band below the taenia of the Doric epistylium, extending the width of the triglyph, and having six guttae depending from it. It also signifies the space be¬ tween two adjoining canals of the triglyphs. Regular. In geometry, a regular body is solid whose surface is composed of regular and equal figures, and whose solid angles are all equal. There are five sorts: 1. A pyramid, comprehended underfour equal and equilateral triangles: 2. A cube, whose surface is composed of six i equal squares : 3. That which is j bounded by eight equal and equi- j lateral triangles : 4. That which is [ contained under twelve equal and equilateral pentagons: 5. A body consisting of twenty equal and equi¬ lateral triangles. Regulator, in mechanics, that part of a machine which makes the motion j equable. Regulator-cock, in locomotive en¬ gines, a cock placed to admit oil or tallow to lubricate the faces of the regulator. \Regulator-cover, in locomotive en- ; gines, the outside cover, remov¬ able when required to examine the j regulator. I Regulator-shaft and levers, in loco¬ motive engines, the shaft and levers placed in front of the smoke-box I when each cylinder has a separate 1 regulator. A rod connected with | the shaft leads to the foot-plate, where a handle is placed conve¬ niently for use. Regulator-valve, the valve in a steam- pipe of a locomotive engine, for regulating the supply of steam to the cylinders. Regulator-valve spindle, the spindle for moving the regulator-valve; being fixed to it at one end, the other end of the spindle passes through a stuffing-box joint over the fire-box, and has a handle fixed on the end to turn it. Relief-valve, a valve belonging to the feeding apparatus of a marine en¬ gine, through which the water escapes into the hot well when it is shut off from the boiler. Relieving tackle, in mechanics, the two strong tackles used to prevent a ship’s overturning on the careen, and afterwards to assist in upright- ing her. Repercussion, in mechanics, the act of drawing back ; rebound. Replum, the panel of the impagis, or horizontal rails of a framed door. Repose, in painting, denotes certain parts in the composition of a pic¬ ture which seem to tranquillize its aspect Reredos, behind the back; the back of a fireplace ; also an altarpiece, a screen, or partition wall. Respond, in Gothic architecture, a half-pillar-or piece attached to a wall to support an arch, etc. Rest, in a lathe, a piece of iron to hold the turning-tool upon, fixed at the end of a slide by a set-screw : the slide can be moved at right angles to the bar of the lathe, and the whole can be fixed at any part of the bed, between the centres. Reticulated work, a species of ma¬ sonry or breakwork, formed ex¬ ternally by small square stones or bricks, placed lozengewise, and presenting the appearance of net¬ work. Reticulation is the method of copy¬ ing a painting or drawing by the help of square threads. An open frame is made similar to a strain- REV REYNOLDS. RHO ing frame, and the painting en¬ closed within it; a number of threads are then strained over at equal distances, like network, which are fastened to the frame by nails. The canvas, or paper, is likewise divided into an equal number of proportional squares, and whatever appears within the square threads in the painting is copied into the corresponding squares on the canvas or paper. The squares of the copy may bear any proportion to those of the ori¬ ginal. Painters often adopt this method when they first execute a small design, from which their large and more finished work is copied. Revels, or Reveals, the vertical re¬ treating surface of an aperture, or the two vertical sides of the aper¬ ture, between the front of the wall and the windows or door frames, most commonly posted at right angles to the upright surface. Reversing gear, the apparatus for reversing the motion of a marine or locomotive engine, by changing the time of action of the slide- valve : the eccentric being in ad¬ vance of the crank for the forward motion will, if turned to an equal distance behind the crank, produce a backward motion. Reversing handle and guide, the han¬ dle placed beside the foot-plate conveniently for use when re¬ quired. The guide is a quadrant fixed to the foot-plate, notched for the end of the reversing handle for each variation of the expansion gear. To reverse the engine, the handle is removed to any notch past the centre of the guide on the opposite side in which it was before. Expansion is varied by moving the handle from one notch to another notch on the same side of the centre of the guide from which the engine is working. When the handle is on the centre notch, the handle is said to be out of gear. Reversing lever, the lever connected 388 to a crank on the reversing shaft | by a rod, and placed at the side of j the fire-box, between guide-plates with notches to keep it vertical, I or in the forward or backward position. Reversing shaft, tbe shaft, with levers ■ on it, connected with the eccen-1 trie rods in the rocking-shaft class, I but with the slide-valve rod in the if expansion-gear class of engines. Both arrangements effect the ob¬ ject of moving the slide-valve so]) as to admit steam to the contrary side of the piston to which it had previously been admitted, and thus j reverse its motion, and with it the motion of the engine also. Reversing valve. (See Air-valve.) Reynolds (Sir Joshua) was born in I 1723, in Devonshire. The price l Reynolds first received for a head 1 was five guineas. In 1755 (thirty-'I two years of age) his charge was | twelve guineas. Some years after I his price for a head was tw-enty guineas. In 1758, the account of his studies and distribution of iH time is curious. He received six I sitters daily. In 1760 he raised | his price to twenty-five guineas; I at this he engaged several subor- I dinate labourers. His study was about 15 feet high; the window a was small and square, and the sill I 9 feet from the floor. His sitter’s] I chair moved on castors, and stood (I above the floor 1-| feet. He wrought: I standing, and with great celerity; 1 I the handles of his brushes were 181 f inches long. Reynolds again raised his price for a portrait to thirty- five guineas, and finally to fifty . 1 guineas. Rhomb, an oblique angled parallelo- f gram ; in geometry, a parallelogram; I or quadrangular figure having its!; four sides equal, and consisting of ■ parallel lines, with two opposite; j angles and two obtuse. Rhomboidal, approaching the shape! of a rhomb : in geometry, used to signify an oblique-angled paralle-il logram. RHU ROADS. ROA Rhumb, in navigation, a vertical cir- I cle of any given place, or the intersection of a part of such circle with the horizon. Rhumbs coin¬ cide with the points of the world or horizon, and are distinguished like those of the compass. A rhumb-line cuts all the meridians under the same angle. Rib, in constructive architecture, a moulding on the interior of a vaulted roof. R Rib, an arch formed of a piece of timber. Rib, a pillar of coal left as a support for the roof of a mine. ( Ribs, arch-formed timbers, for sus¬ taining the plasterwork of a vault, or wood ceiling. Ribband, pieces of fir nailed to the timbers of a square body under which shores are fixed. Ribbing, the whole of the timber- work for sustaining a vaulted or coved ceiling. Riders, in ship-building, interior ribs, to strengthen and bind the parts of a ship together, being fayed upon the inside stuff, and bolted through all. I Ridge, the upper angle of a roof: tiles called ridge - tiles are sometimes made very ornamental. ■ Rigger, a wheel with a flat or slightly curved rim, moved by a leather band. Right angle, in geometry, is that formed by a line falling perpen¬ dicularly on another, or that which subtends an arc of ninety degrees. Right line, in geometry, signifies the same as a straight line, opposed to curved or crooked. Ring, in geometry, an annulus. Ring-tail, in navigation, a quadrilate¬ ral sail, occasionally hoisted abaft the after-leech of the boom main¬ sails, to which the fore-leech is made to correspond. Rising-rod, a rod in a Cornish engine which rises by means of levers as the cataract piston descends, and lifts catches which release sectors, and allow weights to shut or open the steam, equilibrium, or exhaust valve. Rivets, short bolts of metal inserted in a hole at the juncture of two plates, and, after insertion, ham¬ mered abroad at the ends, so as to keep the plates together. Mr. Wm. Fairbairn invented a riveting ma¬ chine, which by the aid of steam performs the work rapidly and without noise. Riveting Machine. The principle of action of the riveting machine is very similar to that of an ordinary punching machine. The work per¬ formed by it is usually done by manual labour, which occupies a much longer time, causes great noise, and is much more expensive and less efficient. The machine consists of two strong side-frames forming bearings for the fulcrum for a powerful lever which works between them, and is raised or lowered by a cam acting at the ex¬ tremity. On one end of the cam¬ shaft is a large spur-wheel moved by a pinion on the driving-shaft, which has a very heavy fly-wheel fixed on it, to accumulate power and expend it during the action of the lever. The riveting tool is placed in a guide near the short end of the lever, and directly op¬ posite the end of the tool is ano¬ ther, to form the heads fixed on a pillar called the riveting block. The rivet being made to enter the holes, and placed between the riveting tool and the block, the machine is set in motion, and the cam raises the lever, w'hich presses against the tool and instantly forms the rivet. Roads are artificially - formed ways bet veen distant places, and being among the first means of personal communication, their formation and treatment, as duties of the engineer, are of the highest im¬ portance. The efficiency of road¬ making requires that the surface of the road shall be preserved in a durable condition, and adapted for ROA ROADS. ROA 1 the kind of traffic to be conducted upon it; and, therefore, the con¬ struction of the road, both as re¬ gards its superstratum or surface, and substructure, its dimensions and inclination, or declivity, are equally to be determined with re¬ ference. to the particular kind of wear to which it will be subjected. Thus the weights that will pass over the road will make it neces¬ sary that it possess greater or less firmness and solidity, while the rigidity or hardness of its surface affects the power required for mov¬ ing bodies, or the draught. The vertical inclination of the road has an influence upon the draught, and is also limited by the class of traffic. The old Roman roads, for instance, designed for the passage of animals only, were laid with inclinations of great steepness, and with reference only to the directness of their course. The use of wheel carriages imposes limits to the steepness which cannot be exceeded either with safety or with economy of power. The most improved form of road—the railway—restricts the steepness or inclination still further, the propelling power employed being found to become expensive in a rapid ratio in proportion to the departure of the surface on which it is exerted from a horizontal plane. The qualities of a good road are, solidity of structure,— hardness of surface,—levelness of inclination, and sufficiency of width for all its purposes. To ensure the permanence of these qualities, the formation and the drainage of the road are required to be complete, while the several means to be adopted will be partly determined by the kind of materials at com¬ mand. Experiments made to as¬ certain the force of traction on dif¬ ferent kinds of roads, have shown that this force is nearly in exact proportion to the strength and hardness of the road. Thus the draught on a well-made pavement is half that upon a broken stone surface, or old flint road, and less than a quarter of the draught upon a gravel road. If the strength or solidity of the foundation be in- creased, the draught is reduced. Thus, if the broken stone road be laid upon a rough pavement foun-1 dation.the draught is reduced one- j third, and a similar reduction is effected by laying a bottoming of! concrete formed of cement and gravel. The external forces by , which the motion of bodies upon roads is retarded, and the draught j or power required consequently augmented, are collision, friction, gravity, and the atmosphere. Col -1 lision is occasioned by the hard protuberances and irregularities of j surface of the road meeting the wheels, and thus diminishing the j momentum of carriages. The re-! sistance arising from collision is proportional directly to the load and the height of the obstacle to be surmounted, and inversely to the diameter of the wheels of the carriage in which the load is borne. Professor Leslie has defined the resistance which friction causes to consist “ of the consumption of the I moving force, or of the horse’s i labour, occasioned by the soft sur¬ face of the road, and the continu¬ ally depressing of the spongy and elastic substrata of the road.” From the formulae which have been de¬ duced upon the extent of this re¬ sistance, it is evident that it is caused by the wheels sinking into the ground, and is proportional di¬ rectly to the load, and inversely to , the width of the wheels. The re- j sistance produced by gravity is evi¬ dently in proportion to the steep¬ ness of the road, being nothing on a perfectly horizontal plane, and augmenting as the inclination ap¬ proaches the perpendicular. The force of the air in resisting the motion of loads upon roads may be understood from the experiments which are given in Smeaton’s Re- ROCKING-SHAFT. ROA ports, and from which it appears, that upon a surface of one square foot this force equals 1 lb. when the velocity of the wind is at the rate of 15 miles per hour; and that this force becomes equal to 12 lbs. ■ when the air moves at the rate of 50 miles an hour, constituting a storm. In designing a road, a correct survey of the proposed line, with the exact relative levels of all parts of its present surface is the first requisite, and upon this the engi¬ neer proceeds to consider the pro- ! priety of deviating in one direction I or another, in order to attain better levels, or to equalize the earth¬ works, so that the quantity exca- | vated in one part may suffice to I embank an adjacent portion, and li thus reduce the distances to which II the soil must be removed. In de- i termining the inclinations of the i surface, facts proved by experience I should be consulted, from which I the rule may be inferred that an > inclination of 1 in 35 is that which admits of horses moving with per- I feet safety in a fast trot. Valleys are required to be crossed by bridges and viaducts, or solid em¬ bankments and hills are excavated with cuttings or with tunnels to reduce the elevation to which it would otherwise he necessary to carry the road. Streams and rivers are also occasionally to be passed over, and thus the design and exe¬ cution of an extended length of road frequently involves some of the grandest works of engineering art. Road-making was a principle of employment ingeniously carried out by Napoleon in those countries mastered by his arms ; he disco- I vered one element of the mixing of I the poorer population by the mono¬ polies and greediness of the rich ; his master mind saw clearly that he could not better secure his power I than by employing the unfortunate and labouring poor. Road-making ROC zealously occupied his mind: his name to this day, for this simple and important fact, is revered. In those towns on the Continent where a resume existed of the antagonistic principle, it is obvious that pau¬ perism may be staved off by the more wealthy lords of the soil, if they give employment to the poor; and such conduct on the part of Napoleon naturally produced a ve¬ neration for his name. These poor people desired no cold charity; they sought for sustenance by the means of useful labour; and one of these was road-making. Many of them cheerfully shouldered the musket for the man who had so cherished them. Among the great projects carried out may be mentioned the Simplon road, from Geneva to Mi¬ lan, which cost the French Govern¬ ment seventeen millions of livres, about .£650,000. Roasting of Iron Ore is either to produce higher oxidation, or to expel injurious admixtures. In both cases, liberal access of at¬ mospheric air is required. Ore to be roasted should be broken into pieces as small as those usually put into the blast-furnace. The kind of fuel required is wood, and small charcoal, turf or peat, or brown coal, may be used. There are many different forms of ovens used; all of them can be reduced to that of the blast-furnace or the lime-kiln. These ovens are commonly from twelve to eighteen feet high, and contain from fifty to one hundred tons of ore at one time. Rocking-shaft, the shaft, with levers on it, which works the slide-valves in some steam engines. The ec¬ centric-rod drops on to a stud fixed in one lever, and the links of the slide-valve rod are attached to the opposite lever on the same shaft. This mode of working the slide- valves was generally adopted be¬ fore the introduction, by Mr. Ste¬ phenson, of the direct-action mode of working them. ROD ROMAN ARCHITECTURE. ROM Rod , or pole, a long measure of 16^ linear feet, or a square measure of 272£ square feet. Roller, a solid cylinder of metal or wood, used for many purposes. Rolling Machine, an invention for making the brass mouldings in fenders, and the brasswork in grates. Rolling Mill,a. mill for reducingmasses of iron, copper, or other metals, to even parallel bars or thin plates. This is effected by passing the me¬ tal, whilst red-hot, between two cylindrical rollers of steel, put in motion by the mill, and so mounted in a strong metal frame that they cannot recede from each other. Roll-moulding, a moulding used in early English architecture, resem¬ bling a roll. Roman Architecture, in its masonry, both in public and private build¬ ings, was of far more durable cha¬ racter and more accurate workman¬ ship in the earlier periods than at the decline of the empire. It began with uncemented blocks of stone, passed into the reticulated work of the Republic, thence into the tra¬ vertine, and descended into a mix¬ ture of turf and brick, and stucco facing. The polyhaedral wall, or, as it is often named, the Cyclopean, is the oldest example of masonry in Italy; but this style of building has been used in town walls only. Until about the middle of the last century, Roman architecture was regarded as the Antique and the Classical par excellence, and wms supposed to exhibit the most refined taste and most perfect ar¬ tistic propriety. The ‘ Orders,’ as practised bv the Romans, were the examples taken up and followed by the Italian masters at the period of the so-called Revival, and still con¬ tinue to be followed, both in that country and in France, in prefer¬ ence to their Greek prototypes. Among ourselves, however, the Roman style has of late years fallen somewhat into discredit,—at least as far as the orders are concerned, in —while some have even gone fur- ll ther, and have censured the style jj of the Romans as being compara- II tively rude and coarse in taste, and their system as being radically vi¬ cious and inconsistent. Such is the ' opinion of both Mr. Fergusson and Mr. Freeman; and the latter writer further thinks, that “ if the mad desire of imitating Greece had ne¬ ver taken possession of the Roman mind,” Rome might, by adheringto her own previous mode of construc¬ tion wfith the arch and vault alone, have ultimately wrought out a well- organized style, greatly superior to what she actually did produce, i and which he pronounces to be, although not without its merits, : “ absurd and inconsistent to the last degree.” This almost unqua¬ lified depreciation errs, perhaps, nearly as much as exaggerated and : implicit admiration had done pre- viouslv. Nothing, indeed, is to be said in i favour of the treatment of the two Greek orders by the Romans; for, strange to say, so far from the Doric acquiring greater energy, or the Ionic greater luxuriance, at their hands, the one was emascu¬ lated, the other impoverished, and both of them rendered insipid and characterless. On the other hand, it is to the Romans that we are in¬ debted for almost all that we know of the Corinthian order as a style; and it might, with far greater pro¬ priety, be termed the Roman than the Corinthian one; for they not only greatly affected it and stamped it as their own, but frequently treated it with singular gusto. As to Roman architecture gene¬ rally, it possesses mechanical ad¬ vantages and powers of construc¬ tion unknown to that of the Greeks, and, owing to the adoption of cir¬ cular and other curved forms of | plan, possesses also a degree of va¬ riety and piquancy, if not of highly } refined beauty, that we miss in the ; 1 392 ROM ROM ROMAN SCHOOL. other more polished and correct style. Faulty as the interior of the Pantheon is, in regard to many points of design, Greece could ne¬ ver show anything similar, much less equal to it. The exterior, too, of the same edifice may he quoted as affording an instance of a correct application of a columnar order not introduced as mere decoration be¬ tween arches, but applied as a portico both for actual use and for the sake of the general effect. If it be a mixed system, that of the Romans possesses this advantage : viz. it allows either arcading or colonnading to he employed as may best accord with circumstances, whether in different buildings or in different parts of one and the same edifice. Perfect congruity and simplicity are not the only valuable qualities in architecture ; for there is also a merit and a charm in complexity, when diverse, if not contradictory, elements of construction and de¬ sign are combined into an harmo¬ nious whole; and the Romans ap¬ pear to have been far more studious of impressiveness of ensemble than of purity of form and elegance of detail. Besides a degree of vastness never aimed at by the Greeks, sumptuousness and picturesque¬ ness may be said to have been the predominant characteristics of their i buildings,—at least, of all their principal monuments. Surely, then, we are at liberty to admire Roman architecture for its better qualities, without either be- | ing blind to its faults and defects, | or imitating them, as if they were inseparable from its merits. Cer¬ tain it is, that in all matters of de¬ sign and decoration, modern taste inclines infinitely more to that of the Romans than of the Greeks. Hardly, too, can we dispense with Roman taste and Roman ideas, un¬ less we can dispense with the Ita¬ lian style also: yet the latter style, or one founded upon it, must con¬ tinue to be employed for our secu¬ lar buildings, both public and pri¬ vate, mediaeval architecture being wholly out of the question for buildings generally at the present day. Roman School (The). It has been doubted whether the Roman school possesses the right to that appellation. Because the schools of Florence, Bologna, and Venice were founded by their respective citizens, and supported through a long course of ages; while the Roman school could boast only of Giulio Romano and Sacchi, and a few others, natives of Rome. The other artists were from other parts of Italy. As the Univer¬ sities derive their names from the city where they are established, though the professors may be from other states, so with the schools of painting, the name of the coun¬ try is always attached in prefer¬ ence to that of the master. The masters of the Roman school are— Pietro Perugino. Raffaello, b. 1483, d. 1520. Barocci, b. 1528, d. 1612. Caravaggio, b. 1569, d. 1609. Mola di Como. Andrea Sacchi, b. 1600, d. 1661. Nicholas Poussin, b. 1594, d. 1665. Salvator Rosa, b. 1615, d. 1673. Claude Lorraine, b. 1600, d. 1682. Gaspar Poussin, b. 1613, d. 1675. The characteristic feature of the Roman school consists in a strict imitation of the works of the ancients, not only in sub¬ limity, but also in elegance and selection. Pietro Perugino is the first most eminent name that occurs in the Roman school. His manner is somewhat hard and dry, like that of other painters of his time ; and he occasionally exhibits a poverty in the drapery of his figures. But he atones for these faults by the grace of his heads, particularly in his boys and in his women, which ROM ROMAN SCHOOL. ROM have an air of elegance and a charm of colour unknown to his contemporaries. In the Sistine he has a ‘ St. Peter invested with the Keys,’ and at Perugia the ‘ Mar¬ riage of the Virgin.’ This picture is one of the finest objects that noble city affords, and may be con¬ sidered as containing an epitome of the various styles of Pietro. It is a remarkable fact that the period of Da Vinci and Buonar- ruoti embraces not only Raffaello, but Correggio, Giorgione, and Ti¬ tian, and the most celebrated Ve¬ netian painters; so that a man might have seen all these illus¬ trious artists. Raffaello, born in Urbino, 1483. On settling at Rome, his principal pursuit was the study of the remains of Grecian genius, by which he perfected his knowledge of art. He studied, too, the ancient buildings, and was instructed in architecture for six years by Bra- ■ mante. He lived among the an¬ cient sculptors, and derived from them not only their contours and drapery and attitudes, but the spirit and principles of the art it¬ self. He also employed artists to copy the remains of antiquity at Pozzuolo and throughout Italy, and even in Greece. Nor did he derive less assistance from living artists whom he consulted on his compositions. As Michelangiolo had before studied the torso of the Belvidere, so Raffaello also formed himself on this and other marbles. He was employed nine years on the three chambers in the Vatican. Raffaello is placed at the head of his art, not because he excelled all others in every department of painting, but because no other ar¬ tist has ever possessed the various parts of art united in so high a degree. We stand in amaze at the con¬ tours, grace, precision, diligence, and genius which his drawings ex- hibit. In chasteness of design, he was by some placed on a level w ith the Greeks, though this praise we must consider as extravagant. He selected the beautiful from nature, and, as Mariette observes, he copied it with all its imperfec¬ tions, which he afterwards gradu¬ ally corrected, as he proceeded with his work. Critics have often wished that his female heads pos¬ sessed a more dignified character. His children are not so beautiful as those of Titian. The heads of his men are the most perfect. As to expression, there is not a movement of the soul, there is.not a character of passion known to the ancients and capable of being ex¬ pressed by art, that he has not caught, expressed, and varied, in a thousand different ways, and al¬ ways within the bounds of pro¬ priety. In regard to colour, Raffaello must yield to Titian and Correg¬ gio, although he excelled Michel¬ angiolo. His frescoes may rank with the first works of other schools in that line ; not so his picture in oil. In composition, he is at the head of his art. Giulio Pippi, or Giulio Ro¬ mano, was the most distinguished pupil of Raffaello. He resembled his master more in energy than in deli¬ cacy of style, and was particularly successful in subjects of war and battles. In style of design he emu¬ lates Michelangiolo, and commands the whole mechanism of the human body. His demonstrations of mo¬ tion are too violent. He generally painted in fresco, and his vast works at Mantua place him at the head of that school. Gianfrancesco Penni, of Florence, called II Fattore, was a principal scholar of Raffaello. Of his works, his frescoes in Rome have perished, and few of his oil pictures remain. He is charac¬ terized by fertility of conception, 394 ROM ROMAN grace of execution, and a singular talent for landscape. Francesco Primaticcio was a pupil of Giulio. Giovanni da Udine was Raf- faello’s principal assistant in the arabesques of the Loggie. Perino del Vaga. Vasari con¬ sidered him the best designer of the Florentine School, after Mi- chelangiolo. Polidoro da Caravaggio, a la¬ bourer in theVatican, distinguished himself in the imitation of antique bassi-relievi painting in chiaro-os- curo. Nothing of this kind was more perfect in composition, me¬ chanism, or design. Benvenuto Tisio, called II Garofalo, studied under Raffaello. Rome, Bologna, and other cities of Italy abound with his pictures from the lives of the Apostles. They are of various merit, and not wholly painted by himself. Gaudenzio Ferrari, assistant of Raffaello in Aibano. He never, however, equalled his master in grace, although he had a bolder tone of colour, greater invention, and more vigour of subject. He died in the prime of life. Rome possesses many of his pictures, particularly in fresco, in the churches; and in the Quirinal Pa¬ lace is ‘ Joseph found by his Bre¬ thren,’ which is esteemed a most beautiful piece. There are also many of his pictures to be found in private collections; and in his landscapes, in which he excelled, it is doubted whether the figures are by him. j. Andrea Sacchi was a pupil of Aibano. He was the best colourist of the Roman school, and one of the most celebrated in design. Profoundly skilled in the theory of his art, he was slow in execution. His pictures are rare. His compo¬ sitions do not abound with figures, but every figure appears appro¬ priate to its place. He seems born for the grand style—grave miens, 395 SCHOOL. ROM majestic attitudes, draperies folded with care and simplicity; a sober colouring, and a general tone, which gave to all objects a pleasing harmony and a grateful repose to the eye. His picture of ‘ S. Ro- mualdo surrounded by his Monks’ is ranked among the four best compositions in Rome. His ‘ Tran- site di S. Anna’ at S. Carlo a’ Catinari, his ‘ S. Andrea’ in the Quirinal, and his ‘ S. Joseph’ at Corpo alle Case, are also beautiful pictures. He was born in the vi¬ cinity of Rome in 1599, and died in 1661. Poussin (Nicholas). He stu¬ died the Greek statues, and the remains of antiquity afforded him instruction which he could not ex¬ pect from masters. From the Meleager of the Vatican (a Mer¬ cury) he derived his rule of pro¬ portion. As a model of composi¬ tion, he attached himself to the ‘ Aldobrandini Marriage; ’ and from that and from basso-relievos he acquired that elegant contrast, that propriety of attitude, and that fear of crowding his picture, for which he was remarkable, being accustomed to say that a half-figure more than requisite was sufficient to destroy the harmony of a whole composition. He remained in Rome twenty-three years. Of Landscape Painters, Sal¬ vator Rosa, Claude Gellee of Lor¬ raine, and Gaspar Dughel, called Poussin, appeared under Urban. Salvator Rosa and Gaspar Pous¬ sin resembled each other in de¬ spatch. Both these artists were accustomed to commence and finish a landscape and decorate it with figures on the same day. G. Poussin is accused of not having sufficiently diversified his tints, and of adhering too much to a green hue. Maratta supports the art in its decline. Roman balance, in mechanics, the steelyard or statera Romana. ROM ' ROOFS. ROO Romanesque Architecture, a name given to the style of architecture which prevailed after the decline of the Roman empire, from the reign of Constantine till the intro¬ duction of the pointed arch. Roman white is of the purest white colour, but differs from the blanc d’argent only in the warm flesh- colour of the external surface of the large square masses in which it is usually prepared. Rood , in surveying, the fourth part of an acre in square measure, or 1,210 square yards; a rod; a pole; a mea¬ sure of 16^ feet, in long measure. Rood, or roode, a cross; a crucifix or image of Christ on the cross, placed in a church. The holy rood anciently was elevated at the junction of the nave and choir, and faced the western entrance to a church. Rood-loft, a gallery which was gene¬ rally placed over the chancel screen in parish churches, and was an ad¬ dition peculiar to the Church of Rome. The rood-loft or gallery had its real support from the tie- beams which connected it with the walls of the building; but in the Decorative construction it appeared to rest on a range of arches or mullions below. Rood-lofts are formed both of stone and wood. Rood-tower, or steeple, a tower or steeple at the intersection of the nave and transept of a church. Roof, the part above the miner’s head ; that part of the strata lying immediately upon the coal. Roofs, or coverings to buildings, are variously formed, both as to mate¬ rials and construction, although certain essential qualifications are common to all of them. Thus, they are required to effectually exclude the weather, and at the same time impose the least possible weight upon the walls of the buildings over which they are erected; and another purpose which they should be designed to effect is that of aid¬ ing the walls in maintaining their position by acting as ties between them at their highest and least stable points. A roof consists main¬ ly of two parts, viz. the framing or trussing, and the covering, the width of most buildings being too great to be spanned with any prac¬ ticable covering without the sup¬ port of framing beneath it. In order to avoid unnecessarily load¬ ing the walls, the entire roof should be constructed as light as possible consistent with safety and durabi¬ lity, and its several parts so dis¬ posed that the weight shall fall vertically only upon the walls, and have no tendency to force them asunder. In this respect, there¬ fore, the framing of a roof is re¬ quired to act entirely together as the supporter of the covering, and cannot be properly designed to act laterally against the walls as abut¬ ments. Provided this condition is secured, roofs may be formed so as to preserve a level upper surface, or a ridged surface, the adoption of the form depending upon the occasion which may or may not exist for using the exterior of the roof as a place of resort for persons or otherwise. Thus, in the East, and in warm climates, roofs are commonly made flat on the top; while in temperate regions, ex¬ posed to rains, they are usually ridged, the surface being unavail¬ able, and the escape of water faci¬ litated by this form. Flat roofs are generally composed of timber framing, and covered with stone in large slabs, or with artificial cements, or with concrete moulded in rectangular blocks. The timber framing in these roofs consists of main beams which span the roof from wall to wall in one direction, and of rafters of smaller scantling laid transversely to the beams, and notched down upon them; the distance between the rafters being determined by the size of the covering blocks or slabs. ;96 ROO ROOM AND SPACE. ROO Ridged roofs are composed of framings of wood, malleable iron, or cast-iron, and coverings of tiles of burnt clay in various forms, of slate, of iron in rolled sheets or cast plates, of copper or lead in sheets. Each frame of the roof is termed a truss, and consists of se¬ veral members, according to the width of the truss or span of the roof. The principal of these mem¬ bers, in a wooden truss, are the tie-beam, which equals in length the span of the roof, and is laid horizontally across the building, resting at each end upon a wall- plate of timber, a cast-iron shoe, or a stone template ;—the principal rafters, which are two timbers of equal length, framed into the ends of the tie-beam, and meeting, in the manner of the legs of an isos¬ celes triangle, in a point equidis¬ tant from the ends of the tie-beam and at some height above its cen¬ tral point. The apex of the tri¬ angle or ridge of the roof is sup¬ ported by a vertical post, called the king-post, properly framed and se¬ cured to the heads of the rafters and to the tie-beam. The two tri¬ angular spaces thus formed be¬ tween the rafters, tie-beam, and king-post are filled in with other members, according to the size of the truss, and adapted to assist the rafters in bearing the weight of the covering, and to connect each rafter with the half of the tie-beam below it in a firm and substantial manner. In roofs of small span, these additional members are sim¬ ply two struts fixed in a diagonal position from the bottom of the king-post on either side to the middle of the length of each rafter. Inlarger roofsthe requisite strength is attained, and a space saved in the roof (available as a dormitory or store-room), by introducing two vertical posts, termed queen-posts, leaving a space in the centre of the roof between them, these queen- posts being secured by straps below to the tie-beam, and bearing the rafters above. A horizontal beam connects the heads of the queen- posts, and is termed a collar- beam, the centre of which is se¬ cured to a king-post, which sup¬ ports the heads of the principal rafters and the ridge of the roof. Diagonal struts are framed in be¬ tween the rafters and the king¬ posts and queen-posts, and thus complete the truss. The trusses are fixed at intervals, from 7 to 12 feet apart, throughout the length of the roof, and upon their princi¬ pal rafters longitudinal timbers, called purlins, are notched down, and carry the common rafters, which are of minor scantling, fixed parallel to the principal rafters, at small distances apart. According to the kind of covering to be used, thin strips of wood, called battens, are secured to the common rafters, and upon these the slates, tiles, etc., are secured with pegs, or copper nails. Iron roofs, which are much su¬ perior to those of timber, especially for large spans, from their light¬ ness and resistance to fire, are composed of the same essential members as those here described, malleable rods or flat bars being substituted for the tie-beams and king-posts, and the rafters and struts made of sufficient stiffness with bars of malleable L or T-iron, or with cast-iron of suitable form and section. In these roofs all the meeting-points of the several parts of each truss or principal are pro¬ vided with cast-iron shoes, sockets, and connecting-plates, into which the ends of the rafters, struts, and rods are secured with screwed bolts and nuts, or gibs and keys. Room and space, the distance from the joint or moulding edge of one floor timber to the other, which, in all ships that have ports, should be so disposed that the scantling of the timber of each side of the port, and the breadth of the port fore s 397 ROO ROPE MACHINERY. ROY and aft (the openings between the timbers of the frames, if any, in¬ cluded), be answerable. Root , in arithmetic and algebra, de¬ notes a quantity which, being mul¬ tiplied by itself, produces some higher power. Rope, twisted hemp or wire, used in all kinds of buildings, for the ma¬ nagement and control of building, for the construction of bridges, and on board ship ; it is a species of tackle inseparable from the arts. Rope machinery. The simple and beautiful contrivance employed in the dockyards for this most useful material, is contrived by machinery for the spinning of hemp into yarns, and the final preparation of the same into ropes and cables for the navy. The process first em¬ ployed is separating the fibres from the hemp, and disposing them as nearly as possible into parallel jux¬ taposition ; then the conversion of these bundles of parallel fibres into a flattened ribbon-like form called a sliver, and the spinning of this sliver into a yarn, or simple twist. In a valuable treatise in vol. v. of the ‘ Papers of the Royal Engi¬ neers,’ will be found illustrative plates of the machinery employed in this operation in Deptford dock¬ yard, together with an elaborate description. Rosary, an office in the Church of Rome made up of five or fifteen tens of beads, each ten beginning with a Pater-noster, to direct them to say so many Ave Marias in honour of the Virgin Mary. Rose Pink is a coarse kind of lake, produced by the dyeing of chalk or whiting with a decoction of Bra¬ zil wood, etc. It is a pigment much used by paper-stainers and in the commonest distemper paint¬ ings, etc., but too perishable to merit the attention of artists. Rosetta wood is a good-sized East Indian wood, imported in logs, 9 to 14 inches in diameter; it is handsomely veined. The general colour is a lively red-orange. The' wood is close, hard, and very beau-! tiful when first cut, but soon gets i darker. Rose window, a circular window. Rose-wood is produced in the Brazils, the Canary Isles, the East Indies, I and Africa. It is imported in very large slabs, or the halves of trees, ! that average 18 inches wide. The colours of rose-wood are from light hazel to deep purple, or nearly black; the tints are sometimes abruptly contrasted, at other times striped or nearly uniform. It isi very heavy, and most abundantly used for cabinet furniture: large quantities are frequently cut for useI in veneers. Rostrum, the elevated platform or stage in the forum of ancient Rome, from which the orators addressed the people: a platform in a hall or assembly. Rotary motion , the rotation or mo¬ tion of any body round an axis or centre: the velocity of this motion of bodies is proportional to their distance from such centre. Rotunda, in architecture, an appella¬ tion given to any building that is round both within and without side, whether it be a church, saloon, theatre, etc. The rotunda at Rome, called the Pantheon, and the chapel of the Escurial, the bury¬ ing place of Spanish royalty, etc., are of this form. Rouge. The ‘ rouge vegetale ’ of the French is a species of carmine pre¬ pared from safflow’er, of exquisite beauty and great cost. Its prin¬ cipal uses consist in dyeing silks of rose colours, and in combining with levigated talc to form the paint of the toilette, or cosmetic colours employed by the fair. Roughcast, in building, a kind of plaster mixed with pebbles, and consequently rough on the surface. Roundhouse, the uppermost deck in a ship abaft, sometimes called the poop. Royal Blue is a deep-coloured and 398 RUDDER. RUB beautiful smalt, and is also a vit¬ reous pigment, principally used in painting on glass and enamelling, in which uses it is very 7 permanent; hut in water and oil its beauty soon decays, as is no uncommon case with other vitrified pigments: it is not in other respects an eligible pigment, being, notwithstanding its beautiful appearance, very in¬ ferior to other cobalt blues. Rubble, coarse walling constructed of rough stones, small, irregular in size and shape; a mixture, or the refuse of several kinds of building- stone used for walls exteriorly, or between walls, to fill up. Rubens' Brown. The pigment still in use in the Netherlands under this appellation is an earth of a lighter colour and more ochreous texture than the Vandyke brown of the London shops; it is also of a warmer or more tawny hue than the latter pigment, and is a beau¬ tiful and durable brown, which works well both in water and oil, and much resembles the brown used by Teniers. Rubric, or Madder Lakes. These pig¬ ments are of various colours, and are known by the names of rose, rubiate, rose madder, pink madder, and Field’s lakes. Rudder, the principal matter which guides the ship. The main-piece and the bearding-piece are always oak, and the rest generally fir. The rudder should be bearded from the side of the pintles, and the fore-side made to the form of the pintles; but when they are bearded to a sharp edge at the middle line, which is the customary way, it reduces the main-piece more than is necessary, which is easily per¬ ceived in large ships ; for when the rudder is braced over, the beard¬ ing will not lie close to the stern- post by nearly f of an inch. Rudder irons, or pintles, the irons which are fastened to the rudder in order to hang it up to the stern- post : sometimes there are two of s 2 RUS them cut short to work in a socket in the brace, which makes the rudder work easier. Rudenture, in architecture, the figure of a rope or staff, sometimes plain, sometimes carved, w 7 ith which the third part of the flutings of columns are frequently filled up. Ruderation, in building, a term used by Vitruvius for laying of pavement with pebbles. To perform the ruderation it is necessary that the ground be w r ell beaten, to make it ; firm, and to prevent it from crack¬ ing ; then a stratum of little stones is laid, to be afterwards bound together with mortar made of lime : and sand: if the sand be new, its proportion may be to the lime as three to one ; if dug out of old pavements or from walls, as five to two. Running rigging, in navigation, de¬ notes all that portion of a ship’s rigging which passes through the blocks, to dilate, contract, or tra¬ verse the sails. Russet, Rubiate, Madder Brown, or Field's Russet, is, as its names indi¬ cate, prepared from the rubia tinc- toria, or madder root. It is of a pure, rich, transparent, and deep russet colour, of a true middle hue between orange and purple, not subject to change by the action of light, impure air, time, or mixture of other pigments. It has supplied a great desideratum, and is indis¬ pensable in water-colour painting, both as a local and auxiliary co¬ lour, in compounding and pro¬ ducing with yellow the glowing hues of autumnal foliage, etc., and with blue the beautiful and endless variety of aerial greys. Rustication, the general name for that species of masonry in which the several courses of the stones in each course are distinctly marked by sunk joints or grooves, either chamfered or otherwise cut. Rus¬ tication admits of great variety of treatment, consequently of expres¬ sion also; for, quite contrary to 399 SAC SAFETY-VALVES. SAI what its name literally imports, it is frequently made to show the very reverse of careless rudeness, namely, studied ornamentation, by means of highly finished moulded joints, etc.; and even when the faces of the rustics or stones are Sacellum, a monumental chapel within a church. Sacrarium, a small family chapel in a Roman house; a place for the deposit of anything sacred. Sacristy, a room attached to a church, where the sacred vestments and the utensils belonging to the altars were placed ; termed also the sex- trv, the vestry, etc. Saddle, in ship-building, a piece fitted on the upper end of the lacing. Safety-lamp, a wire-gauze lamp, con¬ structed for the purpose of giving light in mines where fire-damp prevails. Safety-plug, in locomotive engines, a bolt having the centre filled with a fusible metal. It is screwed into the top of the fire-box, that the metal may melt out by the in¬ creased temperature when the water becomes too low, and thus admit the water to put the fire out, and save the tubes and fire¬ box. When the water is allowed to fall below a proper height, there is great risk of spoiling both the fire-box and tubes by the intense action of the fire. This is called ‘burning them;’ and tubes sub¬ jected to such a trial are unfit for use again, as the tenacity of the metal has been destroyed. Safety-valves, in locomotive engines, two valves placed on the boiler for the escape of steam when it ex¬ ceeds the pressure limited by the load on these valves. One of them is placed beyond the control of the engine-man, and is usually called the lock-up valve. The other is regulated by a lever and spring- balance, at a little lower pressure vnrmiculated, or otherwise made rough, it is left to be seen that it is done purposely or artificially, more especially when the vermicu- lation, etc., is made to show a sort of panel surrounded by a smooth border. than the lock-up valve. The aper¬ tures for safety-valves require no nice calculation. It is only neces¬ sary to have the aperture sufficient to let the steam off from the boiler as fast as it is generated, when the engine is not at work. The safety-valve is loaded some¬ times by putting a heavy weight upon it, and sometimes by means of a lever with a weight to move along to suit the required pressure. Safety-valve lever, in locomotive en¬ gines, the lever fixed at one end to a stud, and resting on the valve at a short distance from this stud. Its length is proportioned to the area of the valve, so that the spring- balance may indicate accurately the pressure in lbs. per square inch on the boiler, above the atmosphere. Sagging, in ship-building, a term the reverse of hogging, being applied to the hull of a ship when the middle part of her keel and bottom arch downwards. Sagitta, in architecture, a name sometimes used for the key-piece of an arch. Sailing, plain, in navigation, is that which is performed by means of a plane chart, in which the parallels of latitude and longitude are every¬ where equal. Saint Paul’s, Old. The tower of old St. Paul’s, which had tall lancet windows, was built in 1221. The work of enlargement and restora¬ tion proceeded gradually eastward. In the year 1240, the new choir was consecrated (i.e. was begun), for Henry de Lacy and Ralph de Baldoch, who survived to the reign of Edward II., were benefactors to 400 SAI the “ new work at the east end, which is no way distinguishable from the rest of the choir.” This choir was therefore aboutforty years in building. Taking this work at a medium between the first and last of these dates, we have a per¬ fect specimen of English archi¬ tecture in the earlier years of Ed¬ ward I. Here the false arches of the dado are retained, but instead of the single and slender columns of the former era, they are sus¬ tained on pillars more massy and slightly clustered, of which the capitals resemble a rose, while the cusped arch is surmounted by a sweep highly pointed; of these the spandrils are filled with quatre- foils, and a rose appears beneath. The triforia remain nearly the same as in the earlier period, but the windows have lost the side co¬ lumns, the mullions are angular, and the three lights of those in the north aisles surmounted by rich tracery. ( Quar. Rev. of Dr. Milner , 1811.) Saints’ bell, a small bell used in the Roman Catholic worship, to call attention to the more solemn parts of the service. Salt-cellars, in Tudor times, were pieces on which the taste and fancy of goldsmiths were severely exer¬ cised. These artists were held in high estimation, and ranked with architects and sculptors. Benve¬ nuto Cellini, in the time of Henry VII., was the greatest designer and chaser, or sculptor in gold and silver, in Europe: he visited England at this period, and ex¬ cited much attention. Sanctum Sanctorum, or holy of holies, the most sacred part of the temple of Jerusalem, containing the ark of the covenant. Sanctuary, the presbytery or eastern part of the choir of a church in which the altar is placed. Sand is the term applied to any mi¬ neral substance in a granular state, where the grain is of an appreci- SAN able size, and insoluble in water. It is more particularly denominated from the prevailing substance, as siliceous sand, iron sand, etc. Sand is of general use for the mixing of material in building: river sand is far preferable. Sand-boxes, in locomotive engines, boxes filled with sand, usually placed near the driving wheels, with a pipe to guide the sand to the rails, to be used when slipping takes place. Sand-stone, a soft porous kind of stone, generally known by the name of free-stone. It is com¬ posed of small particles of quartz in rounded grains, united by an argillaceous or calcareous cement. Sandal wood, a tree having somewhat the appearance of a large myrtle. The wood is extensively employed as a perfume in the funereal cere¬ monies of the Hindoos. The deeper the colour, which is of a yellow brown, and nearer to the root, the better is the perfume. It is imported in trimmed logs from 3 to 8, and rarely 14 inches in dia¬ meter, and the wood is in general softer than box-wood, and easy to cut; it is used for parts of cabinets, necklaces, ornaments, and fans. Sanitary Precautions, for London in its southern district, were discussed nearly half a century since. Ralph Dodds, an eminent engineer of that period, writes, in his exhortation for a better supply of pure water, the following: “ I cannot help noticing that part of the south metropolis, St. George’s Fields, lies 4 or 5 feet below the flow of high water, and is so badly drained, and I may say, so saturated with filthy water, with other deposits of every species of dirt and filth from the City and Southwark, that it must be the first place to invite pestilence, should it ever be generated in this part of the country. I hope this will meet the eye of those who wait only for information to im¬ prove its situation.” SANDAL WOOD. 401 SAPPHIRE. SAP Sapan wood or buckum wood, is a middle-sized tree, indigenous to Siam, Pegu, etc.: for purposes of dyeing it is inferior. Sap-green , or Verde Vessie, is a vege¬ table pigment prepared from the juice of the berries of the buck¬ thorn, the green leaves of the wood, the blue flowers of the iris, etc.: it is usually preserved in bladders, and is thence sometimes called bladder green ; when good, it is of a dark colour and glossy fracture, extremely transparent, and of a fine natural green colour. Though much employed as a water colour ■without gum, which it contains naturally, it is a very imperfect pigment, disposed to attract the moisture of the atmosphere and to mildew ; and having little dura¬ bility in water-colour painting, and less in oil, it is not eligible in the one, and totally useless in the other. Sapphire, a pellucid gem, which in its finest state is extremely beautiful and valuable, and inferior only to the diamond in lustre, hardness, and value. Its proper colour is pure blue; in the finest specimens it is of the deepest azure, and in others it varies into paleness, in shades of all degrees between that of a pure crystal brightness and water without the least tinge of colour, but with a lustre much su¬ perior to the crystal. The gem known to us by this name differs greatly from the sapphires of the ancients, which was only a semi¬ opaque stone of a deep blue, veined with white, and spotted with small gold-coloured spangles in the form of stars. Saracenic Architecture is a species of architecture derived by the Euro¬ peans from the Arabs, or Saracens, during the crusades. Sarcophagus, a stone coffin or grave in which the ancients laid those they had not a mind to burn. Sash, a chequered frame for holding the squares of glass in windows, SAW and so formed as to be let up and dowm by means of pulleys inserted, or other contrivances. The ordi¬ nary sashes are either single or double hung. Sassafras wood is a species of laurel, and the root is used in medicine: it measures from 4 to 12 inches in diameter. It is sometimes used for cabinet-w'ork and turnery. Satin-wood. The best variety is the West Indian, imported from St. Domingo both in square logs and planks, from 9 to 20 inches wide, j The next in quality is the East Indian, logs from 9 to 30 inches j diameter. The wood is close, not so hard as box-wood, but some¬ what like it in colour, or rather more orange ; some pieces are very beautifully mottled and curled. It is much used for internal decora¬ tions and furniture. It is also used for many oiher purposes for its light and agreeable tone. Saucers, small deep dishes, for sauces, etc., and also used as stands for vases, and other vessels filled with wines, to prevent the liquor being j spilt upon the table. In the reign 1 of Elizabeth, dishes and platters, which before her time were quite flat, began to assume their present form. Saul, or Sal, an East Indian timber- tree. This wood is in very general use in India for beams, rafters, and various building purposes ; is close- grained and heavy, of a light brown colour, not so durable, but stronger than teak, and is one of the best timber trees of India. Saunders Blue (a name corrupted from cendres-bleu). the original deno¬ mination probably of ultramarine ashes, is of two kinds, the natural and the artificial. The artificial is a verditer, prepared by lime or an alkali, from nitrate or sulphate of copper. The natural is a blue mineral, found near copper mines, and is the same as mountain-blue. Saw, a toothed instrument which serves to cut into pieces several 402 1 SAW SAW MILLS. solid matters, as wood, stone, I ivory, etc. The best saws are of tempered steel, ground bright and smooth; those of iron are hammer- hardened : hence the first, besides their being stiffer, are likewise found smoother than the last. They are known to be well ham¬ mered by the stiff bending of the blade, and to be well and evenly ground by their bending equally in a bow. The edge in which are the { teeth is always thinner than the I back, because the back is to follow j the edge. The teeth are cut and sharpened with a triangular file, the blade of the saw being first fixed | in a whetting-block. Saw file , a triangular file for sharp¬ ening a saw. Saw Mills. The very ingenious ma¬ chinery constructed by the late Mr. Henry Maudslay is employed in the dockyards to saw timber, and for cutting deals and the several kinds of timber used in the navy and in public works, into the several scantlings, sizes, forms, or shapes. In vol. vi. of the ‘ Papers of the Royal Engineers ’ will be found a most ample statement of the processes for sawing, and cut¬ ting, and hoisting by steam power, in Chatham dock, together with engravings illustrative of every operation in these works. Saxon Style of Architecture. This is easily recognized by its massive columns and semicircular arches, which usually spring from capitals without the intervention of the en¬ tablature. In the first Saxon build¬ ings, the mouldings were extremely simple, the greater part consisting of fillets and plat-bands, at right angles to each other, and to the general surface. The archivolts and imposts were similar to those found in Roman edifices. The general plans and disposition of the latter Saxon churches were as follow: the chief entrance was at the west end into the nave, at the upper end of which was a cross, SAX with the arms of it extending north and south; the east end, contain¬ ing the choir, terminated in a se¬ micircular form. A tower was erected over the centre of the cross, and to contain the bells an¬ other was frequently added, and sometimes two. The large churches contained a nave and two side aisles, one on each side of the nave, and were divided into three tiers or stories, the lower consisting of a range of arcades on each side, the middle a range of galleries between the roof and vaulting of the aisles, and the uppermost a range of windows. The pillars were either square, polygonal, or circular. Such was the thickness of the walls and pillars, that but¬ tresses were not necessary, neither were they in use. The apertures were splayed from the mullions on both sides. The dressings are ge¬ nerally placed on the sides of the splayed jambs and heads of the arches, and but seldom against the face of the walls ; and when this is the case, the projectures are not very prominent. The dressings of the jambs frequently consist of one or several engaged columns upon each side. The imposts, parti¬ cularly those of the windows, have frequently the appearance of being a part of the wall itself. The doors in general w’ere formed in deep re¬ cession, and a series of equidistant engaged columns placed upon each jamb, and were such, that two horizontal straight lines would pass through the axis of each series, and would, if produced, terminate in a point. Each column is at¬ tached to a recess formed by two planes, constituting an interior right angle. The angle at the meeting of every two of these re¬ cesses formed an exterior right angle, which was sometimes ob- tunded, and frequently hollowed. The archivolts, resting on the ca¬ pitals of the columns, are formed on the soffit shelving, like the 403 SCA SCOLA. SCFI, jambs below. The ornaments of columns and mouldings are of very simple forms. The rudely sculp¬ tured figures, which often occur in door cases, when the head of the door itself is square, indicates a Roman original, and are mostly referable to an era immediately preceding the Conquest. Scabellum, in ancient architecture, a kind of pedestal, commonly ter¬ minating in a sort of sheath or scabbard, used to support busts, etc. Scagliola, in the arts, a composition, an imitation of marble, laid on brick in the manner of stucco, and worked off with iron tools. Scala, a ladder, a staircase, from Scala Santa, a building at Rome, erected from the designs of Fontana, with three flights of stairs. The build¬ ing is so called because the middle flightconsists of twenty-eight steps, said to have been passed over by our Saviour in his progress to the house of Pilate. They were sent from Jerusalem to Rome by St. Helena, and are objects of reve¬ rence to Roman Catholic pilgrims. Scale, in painting, a figure subdivided by lines like a ladder, which is used to measure proportions between pictures and the things repre¬ sented. Scamillus, a small plinth below the bases of Ionic and Corinthian co¬ lumns. Scantling, the transverse dimensions of a piece of timber in breadth and thickness. Scantling, is also the name of a piece of timber, as of quartering for a partition, or the rafters, purlin, or pole-plate of a roof. All quartering under five inches is termed scant¬ ling. Scantling, in masonry, the size of the stones in length, breadth, and thickness. Scapple: to scapple a stone is to re¬ duce it to a straight surface with¬ out working it smooth. Scarcement, a plain flat set-off in a wall. Scapus, in architecture, the shaft of a column. In botany, a flower- stalk springing straight from the root, as in the primrose, snow¬ drop, etc. Scarf, to lap the ends of plank or timber one over the other, to ap¬ pear as one solid piece, as keel- pieces, clamps, etc. Scarfed, in carpentry', signifies pieced, or joined, being a particular method of uniting two pieces of timber by their extremities. Scarfing, the junction of two pieces of timber by being bolted or nailed transversely together, so that the two appear as one. Scarlet Lake is prepared in form of drops from cochineal, and is of a beautiful transparent red colour and excellent body, working well both in water and oil, though, like oilier lakes, it dries slowly. Strong light disco! iurs and destroys it, both in water and oil; and its tints with white lead, and its combi¬ nations with other pigments, are not permanent: yet when well prepared and judiciously used in sufficient body, and kept from strong light, it has been known 1 to last many years; but it ought never to be employed in glazing, nor at all in peformances that aim at high reputation and durability. Scarp, in heraldry, signifies the scarf worn by military commanders. Scena, the permanent architectural front which faced the audience part of a Roman theatre : it some¬ times consisted of three several ranges of columns one above an¬ other. Scenography, in perspective, the re¬ presentation of a body on a per¬ spective plane; a description there¬ of in all its dimensions, such as it appears to the eye. Schola, the margin or platform sur¬ rounding a bath. It was occupied by those who waited until the bath was cleared. The schola was also a portico corresponding to the exedra of the Greek palaestra, and 404 SCREW. SCH 1 SCR was intended for the accommoda¬ tion of the learned, who were accustomed to assemble and con¬ verse there. Schools of Painting. A school in the fine arts denominates a class of artists who have learned their art from a certain master, either by receiving his instruction or by studying his works, and who of consequence discover more or less of his manner from the desire of imitation, or from the habit of adopting his principles. All the painters which Europe has pro¬ duced since the renovation of the arts are classed under the following Schools: the School of Florence, the School of Rome, the School of Venice, the Lombard School, the French School, the German School, the Flemish School, the Dutch School, the Spanish and the Eng¬ lish School. Schooner, in navigation, a small two- masted vessel whose mainsail and foresail are suspended from gaffs and stretched out below by booms. Schweinfurt Blue appears to be the same in substance as Scheele’s green, prepared without heat, or treated with an alkali. It is a beautiful colour, liable to the same changes, and is of the same habits as blue verditer, and the above ineligible pigment. Sciography, in architecture, the pro¬ file or section of a building, to show the inside thereof. In astro¬ nomy, the art of finding the hour of the day or night by the shadow of the sun, moon, or stars. Sconce, in manufacture, a pensile candlestick, generally with a mirror to reflect the light. Scotia, the hollow moulding in the base of ?- Ionic column, derived from the Greek, signifying shade, because, from being hollow, part of it is always in shadow. The scotia is likewise a groove or chan¬ nel cut in the projecting angle of the Doric corona. 405 Scovanlode, a lode having no goz- zan on its back or near the sur- j face. Scraper, a piece of iron used to take out the pulverized matter which remains in a hole when bored previous to blasting. Screen, a movable framework to keep off an excess of light, or heat, or cold ; a separation ; a partition. In ecclesiastical architecture, a screen denotes a partition of stone, wood, or metal; usually so placed in a church as to shut out an aisle from the choir, a private chapel from the transept, the nave from the choir, the high altar from the east end of the building, etc. Some very beautiful examples exist of screens, especially of those se¬ parating the choir from the nave. That of York is of a magnificent character. ‘ All Saints’ Church, Maidstone,’ a work published in 4to, is of an interesting description on this head. In modern archi¬ tecture,asingle open colonnade, ad¬ mitting a view through it, is called a screen of columns: such was that formerly in front of Carlton House. Grosvenor House has a Doric screen in front of it. Screen bulk-head, in ship-building, that which is under the round¬ house. Screw, a spiral groove or thread winding round a cylinder so as to cut all the lines drawn on its sur¬ face parallel to its axis at the same angle. The spiral may be either on the convex or concave surface of the cylinder, and it is called accordingly either the screw or the nut. The screw can hardly be called a simple machine, because it is never used without a lever or winch to move it home, and then it becomes an engine of amazing power and utility in pressing to¬ gether substances that have little cohesion, or in raising to short heights ponderous bodies. The smith, the carpenter, the printer, and the packer, all use screws in s 3 SCR SCREW PROPELLER. SCR I their respective occupations. Bales of wool, cotton, hay, etc., may be compressed by means of a screw into packages, the specific gravity of which shall be much heavier than an equal volume of water. Such packages will then sink in the ocean like a cannon-shot. Moreover, many of our domestic operations are performed by means of presses or screws; as the mak¬ ing of sugar, oil, and wine. The screw possesses one great advan- 1 tage over the inclined plane, from j which its principal of action may be said to be derived. The great attrition or friction which takes place in the screw is useful by retaining it in any state to which it has once been brought, and continuing the effect after the power is removed. It is thus the cabinet-maker’s cramp, the smith’s vice, and all those instruments made by mathematical instrument- makers in which screws act, can be employed with certainty. Screws are made with threads of various forms: some have sharp, others square or round threads. Screw-jack, a strong screw for lifting or supporting a heavy weight: it rests, by means of a large nut, upon a hollow base or pedestal, and is raised or lowered by turning the nut. Screw. Screw propellers, for naviga¬ tion, by means of steam power, have now become objects of importance to all nations, more particularly for those who navigate the broad wa¬ ters : they are especially applicable for vessels of war, the machinery for propulsion being without the reach of shot. Screw propellers, however variously they may be modified, all derive their power of propelling by being placed on an axis which is parallel to the keel, and by hav¬ ing threads or blades extending from the axis, which form seg¬ ments of a helix or spiral, so that, by causing the axis to revolve, the threads worm their w r ay through the water, much in the same way as a carpenter's screw inserts itself i into a piece of wood. There is, however, considerable difference between the action of a carpenter’s screw and of the screw propeller: the latter, acting upon a fluid, cannot propel the vessel without causing the water to recede, while the carpenter’s screw progresses through the wood without any such recession. The law which governs the distance which the water re¬ cedes is common to the paddle- wheel, and to all bodies moving in the water. The screw propelling is not of recent construction; we find that so early as 1727, Mr. Duquet invented an hydraulic screw ma¬ chine, which he placed between two boats, connected by transverse bearing, to which the screw was af¬ fixed. Mr. Paucton, in 1768, pub¬ lished his ‘ Theory of the Screw of Archimedes;’ other inventions followed, until a recent date, when Mr. George Rennie applied his comprehensive mind to the sub¬ ject. Sir John Rennie and Mr. George Rennie undertook, when all other engineers declined the order, to construct the engines for the Ship PropellerCompanyformed in 1836, to work out Mr. J. P. Smith’s patent for the application of the screw to propel steam ves¬ sels, by placing it in a space to be left for that purpose, in that part called the ‘ dead-wood ; ’ that is, the solid wood-work between the stern-post and the keel of the ves¬ sel, This screw-propeller vessel was at length launched, and the engines, by the Messrs. Rennie, constructed. This vessel, named the ‘ Archimedes,’ of 232 tons and 80-horse power, was brought out in 1840; the success was com¬ plete, and the publicity given to her performances by her spirited owners, who took her round Great Britain and showed her powers in every port, rendered the capa¬ bilities of the screw no longer a 406 SCR SCREW PROPELLER. SCR matter of doubt; she was in the threaded screw, as shown in the first instance fitted with a single- | accompanying diagram. Other patents were subsequently taken out, and many experiments made. In 1838, Mr. Ericsson ob¬ tained a patent for a propeller con¬ sisting of six blades, a a a a a a, set at equal distances round a cy¬ linder concentric with the axis b : the blades and arms were segments of a screw. The Archimedean screw is a helix, consisting of an inclined plane wound round a cylinder. When such a screw has commu¬ nicated a retrograde motion to the water equal to its own recession, the further continuance of the thread will not only be useless, but will occasion a friction by its unnecessary surface. Mr. Rennie proposed to make the screw spiral instead of helical; the thread of 407 SCR SCREW PROPELLER. SCR his propeller would thus be gene¬ rated by winding an inclined plane round a logarithmic cone or spire. The accompanying diagram will probably best explain the method adopted. Various other methods have since been suggested and adopted ; one by Mr. Blaxland. This propeller shaft rests upon a bearing in the false stern-post, which is fitted with a stuffing box. There is an open space on the dead-wood, in which the propeller works, similar to that of the ‘ Archimedes,’ but the propeller rests entirely upon the bearing, instead of having an after-bearing like the screw of that vessel. Captain Carpenter’s in¬ vention w T as adopted by the Ad¬ miralty in the pinnace ‘ Geyser,’ commanded by himself. There are in this case two propellers, which are placed in the quarters. They receive motion by means of a rotatory engine, called the disc engine. The propellers differ from all others, consisting merely of two flat trapeziums attached by arms to the axis : they are therefore not portions of a screw, though this action is helical. In May, 1843, Mr. BennetWoodcroftwas directed by the Lords of the Admiralty to make a screw at his own cost, which they caused to be tried in the ‘ Rattler.’ This screw was made of copper, having four blades; and it corresponded in every respect with a screw- of a uniform pitch, also made of cop¬ per, in the number of its blades, its diameter, length and pitch, with this exception, that although they each commenced with the same pitch, yet Mr. Woodcroft’s screw 408 | SCR SCREW PROPELLER. SCR gradually increased in its pitch through¬ out, and terminated with an increase of 5 percent, additional pitch. The trial of Smith’s four-bladed Archimedean or true screw took place in the ‘ Rattler,’ on the 18th of March, 1844; and on the 13th of the following month, a trial of Wood- croft’s increasing- pitch screw, of four blades, was made with the same vessel. After this trial, Mr. Lloyd, the chief en¬ gineer of the Admi¬ ralty, who had been present to superin- I tend it, stated to Mr. Woodcroft, who had also been present, that the latter screw was superior to the uniform pitch screw' in two important qua¬ lities ; first, that it propelled the vessel at an equal speed with less power; and, se¬ condly, that it also | propelled the vessel at an equal speed with fewer revolutions of the screw, which i' latter quality he considered supe¬ rior to the former ; but that the difficulty arising from having to drive screws so fast, constituted the greatest obstacle to their in¬ troduction in the Royal Navy. In¬ deed, this is the admitted difficulty in the application of the screw as a marine propeller, and the prac¬ tical difference between it and the paddle-wheel. The great size of latter enables the speed of the engines to accomplish the required velocity of the boat, whereas the small diameter of the screw renders it necessary that it should perform many more revolutions than the engine makes strokes. Hence the necessity of introducing some mul¬ tiplying gearing between the engine and the propeller; and this multi¬ plying gear, consisting of cast-iron cog-wheels and pinions, is neces¬ sarily liable to frequent breakage and damage. The great object to be now achieved in the application of the screw as a marine propeller, is to introduce an intermediate gearing for multiplying the velo¬ city, which shall not be liable to accident, or to render this gearing altogether unnecessary. Smith’s screw, however, with some modifi¬ cations of his former patent, now 409 SCREW. SCR diminished to two bladess, is used in the navy to some extent, as well as a more recent invention of Mr. Griffiths, whose trials have been generally successful. Screw-cutting Machine. The ma¬ chinery adapted to this purpose varies in construction according to the notions of the different makers, but the general principle is the same in all, the difference consist¬ ing in the method of carrying it into effect. The machine is a compound of the ‘ slide-rest ’ and lathe, with a train of wheels to give motion to the former. The metal to be cut into a screw is placed between the centres of the lathe in the usual manner, and the cutting-tool is fixed upon the slide rest, which has its lower slide made parallel to the centre line ; the upper slide is only used for adjusting the cutting- tool. The screw of the lower slide has motion communicated by the train of three or more wheels; the first, or driving wheel, is fixed on the mandril of the lathe, and last of the train is fixed on the end of the slide-screw; the other wheels are intermediate wheels. The pitch of the screw to be cut, or distance between the centres of two consecutive threads, is the space traversed by the tool du¬ ring one revolution of the work, and is regulated by the sizes of the wheels which must therefore be changed for every difference in the pitch. The perfection to which screw¬ cutting has been brought, is mainly attributable to the application of the slide-rest; and the beautiful and accurate screws, of all sizes, produced by the screw-cutting ma¬ chine, have contributed in no small degree to the perfection of our ma¬ chinery in general, and more par¬ ticularly to that of astronomical instruments. There are also other machines, called screwing machines, for screw-cutting, which perform work SCR of a much rougher description, such as cutting short screws or bolts, for fastening together the flanges of pipes, etc. The machine consists of a strong iron frame, which carries a mandril somewhat similar to that of a lathe, driven by a band passing over a pulley. The head of the bolt to be screwed is held by a clamp at the projecting end of the mandril, so that it revolves with it as in a lathe, the only dif¬ ference being, that it is held at one end and free at the other. The dies, or two hardened steel pieces, which together form a nut, with the grooves lengthwise for cutting, are placed in a small frame, across the machine, supported by two guides projecting from the machine frame, one on each side, level and parallel with the bolt. When the machine is set in motion, the small cross frame is brought forward, and the end of the revolving bolt is made to enter the dies, which are pressed upon it by set-screws; and as their cutting edges take effect on the bolt, the frame is carried forward on the guides till it has moved the required length ; it is then brought back by reversing the motion of the ma¬ chine, and the dies are tightened for another cut: this operation is repeated until the screw is of the required diameter. By fixing a tap, or cutting-screw, to the mandril, in place of the bolt, and holding a nut by the screws in the cross¬ frame, the machine is made to cut internal screws. Scribing, a term applied to the edge of a boai’d when fitted upon any surface. Scribing, in joinery, the act of fitting one piece of wood upon another, so that the fibres of both may be perpendicular to each other, and the end cut away across the fibres, soastofituponthe slide of theother. Serin, in mining, a small vein. Scroll, a name given to a kind of ornament of general use, which 410 SCULPTURE. SCU resembles a band arranged in un¬ dulations or convolutions. Sculpture is the art of carving wood or hewing stone .into images. It is an art of the most remote anti¬ quity, having been practised, there is reason to suppose, before the Deluge. To this reason is assigned the expedients by which, in the first stages of society, the images of men have everywhere supplied the place of alphabetical characters. These, it is universally known, have been picture writing, such as that of the Mexicans, which, in the progress of refinement and knowledge, were gradually improved into the hiero¬ glyphics of the Egyptians and other ancient nations. To make a dis¬ tinction between carving and sculp¬ ture, the former belonged exclu¬ sively to wood and the latter to stone. The latter evinced vast comprehension of mental taste and study of human anatomy as well as that of other animals. In exa¬ mining the various sculptures of the Egyptians, it is found that a general character prevails through¬ out their outlines : many valuable specimens remain to attest their greatness in this art. It is to the Greeks that great superiority is due. The art of sculpture probably was influenced by the climate over the human frame, as the violent heats of the torrid zone and the excessive cold of the polar regions are un¬ favourable to beauty : it is only to the mild climates of the temperate regions that it appears in its most attractive charms. The Romans displayed great talents for statuary; subsequently the Italian masters showed their eminence in the art; and in our own country the works of Westmacott and Chantrey be¬ long to the distinguished English School. Carving in wood exists in the fine and most elaborate works of Flemish masters, and those of Gibbons and others of England are of equal talent in this pleasing art. SCU The Grecian marbles in the Bri¬ tish Museum have given so much grace to British art, and to execu¬ tion in the art generally,that a short description of them, and their con¬ nection with architecture, will not be unacceptable. We learn from Athenian Stuart, that “the Temple of Minerva, called the Parthenon and Heca- tompedon, was built during the administration of Pericles, who em¬ ployed Callicrates and Ictinus as architects, under Phidias, to whom he committed the direction of all works of elegance and magnifi¬ cence. It has been celebrated by some of the most eminent writers of antiquity, whose accounts are confirmed and illustrated in the de¬ scriptions given us by those travel¬ lers who saw it almost entire in the last century. Even in its present state, the spectator on approaching it will find himself not a little af¬ fected by so solemn an appearance of ruined grandeur. Accustomed as we were to the ancient and modern magnificence of Rome, and by what we had heard and read, impressed with an advantageous opinion of what we were come to see, we found the image our fancy had preconceived greatly inferior to the real object. “ This temple, the most costly and highly finished example of the Doric order, perhaps the largest octastyle temple of antiquity, had the advantage of the great mind of Phidias. It is to Lord Elgin’s enterprise and enthusiasm for art that England owes the unique trea¬ sures deposited in the British Mu¬ seum. Pausanias remarks, ‘ On entering the temple called the Par¬ thenon, all the works in what are termed the pediments (eagles)seem to relate to the birth of Minerva ; those behind represent the contest of Neptune and Minerva concern¬ ing Attica; but the statue itself (of the goddess) is formed of ivory and gold.’ Pausanias then proceeds to 411 SCULPTURE. scu a minute description of the chrys¬ elephantine statue, notices other monuments of art, describes the Erechtheum, and enlarges on the colossal bronze Minerva by Phidias, called Promachus, etc. The beauty of the marble of the mountains surrounding Athens, particularly that of Pentelicus, from which the temple Parthenon was wrought, must have given a great zest to the Athenians in the cultivation of the refinement of architectural design : with more brilliancy, it is almost capable of receiving the high finish of ivory. According to Pliny, Dio- posnus and Scyllis, born in Crete about the 50th Olympiad, b.c. 578, were the first sculptors distinguish¬ ed in working marble, and to them are also attributed the earliest sta¬ tues of ivory and gold. Of the part Phidias had in the design of the Parthenon temple, and in the production of the sculpture in par¬ ticular, a diversity of opinion has existed. It has been supposed that the whole of the sculptural deco¬ rations are the ‘ undoubted ’ pro¬ ductions of that great artist, thus conveying to them a charm, from the association of that great name, which the unequal execution does not entitle portions of them to re¬ ceive : others assert that he had nothing to do with the works, but that he may have designed the sculpture. However, the words ‘ skilful sculptor in marble ’ have been applied by Aristotle to Phidias, in opposition to ‘ statuary,’ given by him to Polvcletus, whose works were principally in bronze, in order to strengthen the probability of his having executed the marble sculp¬ ture of the Parthenon. Pliny states Phidias to have been the first who displayed and perfected the toreutic art, or sculpture formed by the combination of metals and other materials. The fertility of genius of this great sculptor, who was equally skilful in every department of his art, was surprising. He was SCU at the period of the erection of the Parthenon, engaged in so many and such various monuments belonging to the toreutic art, that his atten¬ tion must have been occupied by | them to so great a degree, that any hut a general superintendence of the designs of the temple can scarcely be supposed possible, j When executing the Minerva of the Parthenon, he had already comple- i ted or was engaged on, besides many other statues and groups in ivory and gold, five other statues of that goddess, probably all of them colossal, of which the Mi¬ nerva Promachus, in bronze, in the Acropolis, must have been up¬ wards of 50 feet in height, having been seen from the sea. The pas¬ sage of Plutarch, describing the artists of the structures of Pericles is, ‘ Phidias directed and superin¬ tended all the works of him (Pericles), although they had great architects and artificers; for Cal¬ licrates and Ictinus executed the Hecatompedon, or Parthenon.’ ” Sculpture. Mr. Hailes, in 1825, writes the following.-—“ The introduction of statues of individuals, however eminent and meritorous, into squares and public places, is a no¬ velty in this our metropolis, which, till of late years, seemed to be re¬ served for the sovereign and his family. We have, however, two, which, although not contrary to law, at least to any that I know of, are certainly deviations from long- established custom, and a sort of invasion or trespass upon royal prerogative. That of the late Duke of Bedford, the Triptolemus of his time, in Russell«Square, is an erect figure, surrounded by the attributes of husbandry; and be¬ neath it are some smaller figures, equally symbolic. The late Bishop of E-, going with a friend to look at this statue, was asked by him what he thought would be the fittest inscription for it. His an¬ swer was, ‘ Bovi Optimo Maxi- 412 SCU SCULPTURE. SEA mo.’ It seems extraordinary that his Grace, with these emblems of agriculture about him, has not been made to look towards the country instead of the town. But he looks towards Mr. Fox, the Demosthe¬ nes of our day, in Bedford Square, sitting in a lumpish manner in a sort of curule chair, and habited in a toga, a la Romaine ;—his neck is exposed, and the drapery, pass¬ ing over one of his shoulders across his breast, might very well give occasion, as it did, to one of his old Westminster constituents, to say, ‘ So, Charley, you are going to be shaved, I see.’ These are two very sharp remarks : one from a very highly cultivated man, and a great scholar; and the other from a very coarse observer, but equally shrewd and comical in their way. They seem to supersede the neces¬ sity of any other criterion. We are not happy in this branch of the fine arts ; and the only instance in which we can pride ourselves is not of a late date, being the eques¬ trian statue of Charles the First, by a scholar of John de Bologna, at Charing Cross. Our ill success is perhaps the less to be lamented, as works of this sort, exposed to such an atmosphere as we live in, become in a short time so much defaced as to make it very indiffer¬ ent whether the workmanship he from the hand of a Glycon or a Bacon. All our monuments of this kind seem to represent our chimney-sweepers, a-foot or on horseback, rather than our kings, princes, and other great men.” The late Mr. Nash observed, “ that these criticisms are unjust as well as impolitic: by running down the best, we open the door to the w'orst artists. It is a peculiarly English feeling. If Westmacott’s bronzes, which one hardly dares (in the face of criticism) to pronounce un¬ rivalled in this country, had receiv¬ ed their due praise, the designer of the Duke of Kent, at the top of 413 Portland Place, would never have been suffered to libel the state of English art.” Scumbling is giving a kind of rough dotted shadow to trees, grass, gravel-walks, etc., in a drawing when it is nearly finished. It is performed with a brush having some dark-brown colour in it, hut nearly dry. The hairs of the brush are spread apart, then held in a slanting direction, and swept light¬ ly over the foreground, or where the shadows are wanting. This is prac¬ tised by some artists with consi¬ derable effect. Scuppers, holes cut through a ship’s side for throwingoff the water from the pump. They should be dis¬ posed clear of the guns, standards, the ports below, gangways, etc. Scutcheon, the shield represented in heraldry. Scuttles, holes cut in divers parts of the decks, exclusive of hatchways and ladderways ; likewise holes cut through the ship’s side for air. Scyricum Marmor, a name given by the ancients sometimes to a w'hite, and sometimes to a yellowish mar¬ ble ; both used in the public build¬ ings of the Romans, but seldom in statuary, not being capable of re¬ ceiving a high polish. Sea. The sea covers about three- fourths of the entire surface of the globe. The specific gravity of sea¬ water is about D0277 ; the water of closed seas into which many rivers fall is lighter, as that of the Black Sea and the Baltic. The water of the Mediterranean is more salt than that of the Atlantic, con¬ taining about 4 - 18 per cent., while that of the Baltic contains only D18 per cent, of salt. There are also other mineral substances in sea-water, as iodine, bromine, mag¬ nesia, lime, etc., in small quantities. The temperature of the air over the sea has been proved by obser¬ vation to be more uniform than | that of the air over the land ; places I near the sea have therefore a SEA SEAL. more uniform climate than those at a considerable distance from it. Seal, a device or an engraved inscrip¬ tion : also its impression made on wax. Kings, bishops, and prelates were accustomed to use their several devised seals. Cities, towns, cor¬ porations, companies, institutions, I SEC and public bodies, had their seals. Privy or individual seals were also of frequent use, and some very curious seals exhibit much beauty and ingenuity. That represented in the annexed engraving is the seal of Michael Stanhope, who was | Vice-Admiral of Suffolk in the time of Queen Elizabeth. Seam, in mining, a horse-load. Seams ,the opening between the planks when wrought. Secant, a true line that cuts another or divides it into two parts. Section, a vertical plan of the interior of a building, showing it as it would appear upon an upright plane cutting through it. Though rarely shown, sections are almost as in¬ dispensable as plans; like which they show the thicknesses of the walls, and, in addition, those of the ceilings and floors; and also heights, both of the rooms them- J selves, and of doors and windows; I —moreover, the forms of the ceil¬ ings, whether flat, or coved, or vaulted. In one respect, too, a section partakes of the nature of an elevation, the plane parallel to the line of section being an elevation of the interior, or rather consisting of as many elevations as there are se¬ parate rooms or divisions. Sections may be described as either furnish¬ ed or unfurnished: the latter show only construction and the strictly ! 414 SEPULCHRE. SEC architectural parts; wherefore, if the side of a room happens to be quite plain, without door, chimney- piece, or other feature, that side or space will be a blank, orlittle better. Furnished sections, on the contrary, exhibit, besides what strictly be¬ longs to the architecture and its decoration, mirrors, pictures, sta¬ tues, furniture, draperies, and all other accessories. The number of sections required depends upon the nature of the plan, and what may be worth showing. If the design be worthy of it, there should be as many sections as will suffice to show 7 every side of every principal apartment; though it may not be necessary to repeat the entire sec¬ tion through every floor. Sections are the delicice of architectural il¬ lustration. Sector, in geometry, an instrument of wood or metal, with a joint and sometimes a piece to turn out and make a true square, with lines of sines, tangents, secants, equal parts, rhombs, polygons, hours, latitudes, etc. Sedilia, a name for a seat: the term is applied to the seats for the offi¬ ciating priests, inserted (and some ornamented) in the south wall of a church. Segment of a circle, a part of a circle bounded by an arc and its chord, and either greater or less than a semicircle. Segment of a sphere, any part of a sphere cut off by a plane, the sec¬ tion of which, with the sphere, is always a circle. Sella (Latin), the general term for a i seat or a chair of any description. Sella Curulis, a chair of state. Semaphore, in mechanics, a name given by the French to the tele¬ graph, and latterly adopted in England to signify any machine to communicate intelligence by signs or signals. Semicircle, half a circle, or the area comprehended between a diameter and the semi-circumference. 415 SEP Semi-ordinate, in conic sections, a line drawn at right angles to and bisected by the axis, and reaching from one side of the section to the other. Sepia, Seppia, or JEthiops-mineral. This pigment is named after the sepia or cuttle, which is called also the ink-fish, from its affording a dark liquid, which was used as an ink and pigment by the ancients. From this liquid our pigment sepia, which is brought principally from the Adriatic, may be obtained from the fish on our own coasts; and it is supposed that it enters into the composition of the Indian ink of the Chinese. Sepia is of a powerful, dusky-brown colour, of a fine texture: it works admirably in water, combines cordially in other pigments, and is very permanent. It is much used as a water-colour, and in making drawings in the manner of bistre and Indian ink, but it is not used in oil, in which it dries very reluctantly. Septuagint, the Greek version of the books of the Old Testament, so called because the translation is supposed to have been effected by seventy-two Jews, who are usually j called the seventy interpreters. Sepulchre, a grave, tomb, or place of' interment. Extreme attention to the sepulture of deceased friends characterized nations from remote antiquity, and to be deprived of it was accounted a very degrading circumstance. The Romans were prohibited by a law from burying their dead within the city; and it was a field that the father of the Jews purchased for the sepulture of his wife. “ Hear us, my lord : in the choice of our sepulchres bury thy dead ; none of us shall withhold from thee his sepulchre, but that thou mayest bury thy dead.”—Gera, xxiii. 6. The ancient tombs of the East are remarkable for their durability, and, in some instances, their beauty: they are monuments on which the lapse of SEWERS. SER ages effects no change ; in many instances hewn in the solid rock, they are calculated for duration equal to that of the hills in which they have been excavated. In a garden, hewn out of a rock, was the sepulchre of Jesus. As an instance of a style of modern sepulture, which is rapidly extending, may be mentioned the Cemetery of Pere la Chaise, at Pa¬ ris, which comprehends above 150 acres, thickly studded with chapels, tombs, and monuments, beautified with winding walks, curtained with lofty shady trees, and adorned with plants and evergreens. It contains nearly 16,000 mausolea built of the finest granite, sandstone, and polished Carrara marble, the ex¬ pense of which has been estimated at about 120,000,000 francs, or .£5,000,000 sterling. Serges, the great wax candles burnt before the altars in Roman Catholic churches. Serpentine, the ophites, or serpent- stone of the ancients. Mona mar¬ ble is an example of serpentine, and the Lizard Point, Cornwall, is a mass of it. Serving, in navigation, encircling a rope with line or spun-yarn, to prevent its being chafed. Set-off, or Offset, the part of a wall, etc., which is exposed horizontally when the portion above it is re¬ duced in thickness. Severey, a bay or compartment of a vaulted ceiling. Sewers are subterranean passages or channels for the conveyance of waste waters and other matters from towns and buildings. In order that a sewer shall act with efficiency and promote the rapid discharge of the matters committed to it, it is necessary that it be con¬ structed thoroughly impermeable throughout its entire length, that its interior surface be even and smooth, and present no impedi¬ ments to the sewage, and that its vertical declination be sufficient to SEW prevent any suspension of the cur¬ rent. The sectional area of the sewer should be amply sufficient to contain the entire volume of the sewage, and its form such as will best secure its action with the ! minimum contents. The form of a sewer should be adapted to resist the utmost pressure to which it may be exposed externally from the surrounding materials in which '■ it is constructed; and ready access should be afforded at intervals for examining its condition from time to time, and detecting and re¬ moving any obstruction which may possibly occur to the immediate passage of the sewage. Hence rec¬ tangular forms are utterly inap¬ plicable for these works, the section of which should be entirely curvi¬ linear; and theory and experience have concurred in appointing a sectional form, similar to that of the egg, as best fulfilling the con¬ ditions of strength to resist exter¬ nal pressure, and (the smaller curve being placed downwards) to pro¬ duce the most activity in the cur¬ rent when the quantity of sewage is reduced to the minimum. The simplest and best rule for obtain¬ ing with circular curves a true egg- shaped or oviform section for sewers is that given in the ‘ Rudimentary Treatise on the Drainage and Sew¬ age of Towns and Buildings,’ be¬ longing to the same series with this work, and which is therefore here quoted. “ Let the greater diameter, or that of the upper part of the sec¬ tion, equal 1 ; the less diameter, or that of the bed of the sewer, equal •5; and the entire height of the section equal the sum of these, or 1-5. Then strike a semicircle of 1 diameter for the head or arch of the section, and 120° of a circle of ‘5 diameter for the invert; con¬ nect the arch and invert with side arcs of 1*5 radius, the centres of these side arcs being on the pro¬ duced horizontal diameter of the SEW top arch. These arcs will be truly tangential, both to the arch and invert, and will complete a section well adapted for the practical pur¬ poses of the sewer, and, being so extremely simple in its construc¬ tion, peculiarly ready of application by workmen in forming and using templates, and in testing the accu¬ racy of the work as it proceeds. The proper size or sectional area of sewers is determinable upon the quantity of sewage, and the velocity of its passage, which latter element depends jointly upon the rate of declivity at which the sewer is laid, and the volume of water in motion. The quantity of sewage to be con¬ veyed from a town is made up chiefly of the bulk of the water supplied to the population, the ex- crementitious matters produced, and the quantity of rain-water falling upon the service. The maximum quantity thus accruing during any given period of time will determine the minimum capa¬ city of the sewer, calculated in combination with the rate at which the passage can be effected ; while, on the other hand, the minimum quantity thus accruing will limit the proper radius of the invert of the sewer, so that the friction of the water against the surface of the sewer may be reduced in proportion to the total bulk of the sewage. All junctions of one line of sewer with another, and all changes of direction whatever, should be form¬ ed with curves of the greatest pos¬ sible radius, experiment having proved that the current is impeded in proportion as the radius of cur¬ vature is reduced, and that angular junctions are still more mischievous in suspending the proper action of the channel. Thus in a sewer 2 feet 6 inches wide, a stream having a velocity of 250 feet per minute suffers a resistance from a rectan¬ gular change of direction three times that produced with a curve of 20 feet in radius, and double SEW that produced with a curve of 5 feet radius. The inevitable effect of suspending the motion at these junctions is that the solid particles become deposited, and form a per¬ manent bar, requiring some extra¬ ordinary action or force of water to remove it. “ It is usual to distinguish sewers according to their size and func¬ tions, as first class, or main sewers; second class, or collateral sewers ; and third class, or branch sewers; while the smaller channels for con¬ veying the contributions from in¬ dividual tenements are termed drains. The same rules will apply equally to all of these as far as their proper objects are concerned, al¬ though the peculiar construction to be adopted will of course depend to some extent upon the actual size of each channel. For the larger sew¬ ers, constructions of brickwork are commonly used. These require careful formation, and to be accu¬ rately jointed, and the interior of the invert at any rate smoothly formed with a hard-drying cement. For smaller channels or drains and branch sewers, whole pipes of glazed stoneware are coming into extended employment, and, if truly formed and carefully laid and joint¬ ed, these form very superior ducts for the passage of the sewage. By the use of these pipes, the essential qualification of impermeability is better secured than with brick sewers, the repeated joints of which need great labour and care in con¬ struction, and if formed with infe¬ rior mortar, soon becomes imper¬ fect. As necessary appliances to all sewers and drains, efficient traps or apparatus to prevent the escape of the noxious gases engendered within the channels are really in¬ dispensable, and these are required to be simple in construction and unerring in their action. The en¬ tire subject of the sewage of towns and buildings is now first receiving the attention due to it as a neces- SEWERS. 417 SEX SHEERS. SHE sary condition to the public health; and when this important branch of engineering science shall have been thoroughly investigated by qualified public officers, we may hope for the most useful and salutary prac¬ tice, based upon correct principles, and for corresponding amendment in all that pertains to the subter¬ ranean ways of our cities, towns, and dwellings.” Palladio says, “ The great com¬ mon sewer or the general receiver or sink of all the filth of Rome was near the Senatorian bridge, called S. Marca, a performance of Tarquinius Superbus. Authors tell strange things of its largeness, viz. that a full laden hay-cart could drive through it: upon measuring, I have found it to be 16 feet dia¬ meter. Into this all other sewers of the city do empty themselves, which is the reason that sturgeons taken between the Senatorian and Sublician bridges are better than others, feeding on the filth coming out of this great sewer.” Very recently the Legislature have determinatelv taken up the subject of purifying the Thames and of draining London, and placed funds at the disposal of the Metro¬ politan Board of Works; so that the task, the great task, is fairly in hand, and likely to proceed satis¬ factorily and it is to be hoped successfully. Sextant, in geometry, the sixth part of a circle ; in navigation, etc., an astronomical instrument made like a quadrant, but containing only sixty degrees. Shaft, in architecture, the body of a column or pillar; the part between the capital and base. In mediaeval architecture the term is applied to small columns clustered round pil¬ lars, or used in the jambs of doors and windows. Shaft, in mill-work, a large axle, in contradistinction to a small one, which is called a spindle : thus we say, ‘ the shaft of a fly-wheel,’ ‘the spindle of a pinion.’ Shafts are said to be lying when they are in a horizontal direction, and vertical when they are upright. Shaft, in mining, a sinking or pit, either in the lode or through the country. Shafted impost: according to Profes¬ sor Willis, “those imposts which have horizontal mouldings, the sections of the arch above and of the shaft or pier below such hori¬ zontal mouldings being different.” The latter point is the distinction between what he terms shafted and banded imposts : “ in banded imposts, the sections above and below the impost-moulding are alike, the shaft or pier seeming to pass through its capital.” Shaken, plank or timber which is full of clefts, and will not bear caulk¬ ing or fastening; generally called shakey. Shambles, stalls on which butchers expose their meat for sale. The shambles, or market-place for the sale of flesh, at Frankfort-on-the- Maine, is a curious and ancient ex¬ ample of early shambles. Shank, the space between the chan¬ nels of a triglyph. Shank-painter, a chain bolted to the top-side abaft the cat-head, to lower the anchor of a ship. Sheave, in mechanics, a solid cylin¬ drical wheel, fixed in a channel within a block, and movable about an axis; being used, in connection with suitable tackle, to raise heavy weights, or to increase the me¬ chanical powers applied to remove Sheers, in mining, pieces of wood, placed in nearly a vertical position in each side of a shaft, and united at the top, over which, by means of a pulley, passes the capstan rope: this is for the convenience of lifting out, or lower¬ ing into the shaft, timber or other things of great length and weight. Sheers, in ship-building, etc., are masts or large spars set across each 418 SHE SHINGLE. SHI other at the upper ends, by which contrivance the heavy bodies, such as frame-timbers, masts, etc., are raised. ySheer-hulk, in the navy, an old se¬ venty-four cut down to the lower deck, and fitted up with a pair of sheers, for the purpose of taking out the lower masts of ships pre¬ paring for sea. Sheer-strake, the strake under the gunwale in the top side; it is ge¬ nerally worked thicker than the rest of the top-sides, and scarfed between the drifts. Sheet, in navigation, a rope fastened to one or both corners of a sail, to extend and retain it in a particular situation. Sheet Anchor, in navigation, the largest anchor of a ship. Sheriff’s Posts, two ornamental posts or pillars, set up one on each side of the house of a sheriff or chief magistrate. Shift, the time a miner works in one day. Shift, of timber or plank, is over launching without either piece be¬ ing reduced, as the timbers of the frame, or plank in the bottom. iShingle, coarse sand and pebbles de¬ posited by the surge, accumulating ( in banks and forming dangerous shoals. Lieut.-Colonel Reid, in the second volume of the ‘ Professional Papers’ of the Corps of Royal En¬ gineers, makes the following obser¬ vations on the moving of the shingle of the beach along the south coast of England :— “ The prevailing winds being f westerly, and the highest seas roll¬ ing from the south-west, the peb¬ bles of the beach are gradually carried to the eastward, and a con¬ stant supply is furnished by the falling away of the cliffs. On this coast, therefore, groins so con¬ structed as to prevent the moving shingle from pressing to the east¬ ward cause an accumulation of pebbles. “ It has been ascertained, from observation, that the pebbles of the Devonshire coast are forced to the eastward, along the coast of Dor¬ setshire, as far as the Chesil Bank. The stone pier of Lyme Regis, called the Cobb, does not, as might have been expected, arrest their pro¬ gress ; for, in south-west storms, they are driven over the pier, and the crews in the harbour have had to quit the decks of their vessels, on account of the stones driven over the pier falling on the men. On this account, within a few years, a high wall has been constructed to stop the progress of the shingle at this point. The natural conse¬ quence to be expected from this wall is, that the shingle will accu¬ mulate on the west side of Lyme Regis pier, until it shall roll round the pier-head, as at the harbour of Dover. “The Chesil Bank is not com¬ posed of calcareous pebbles (as stated in a work of deservedly very high reputation), but mostly con¬ sists of siliceous stones, worn to a very remarkable degree of uniform¬ ity of shape and also of size (when taken from the same point) by long attrition upon the coast. The largest pebbles have been carried furthest to the east; and the regu¬ larity with which they are arranged, according to their size, is very re¬ markable. “ The progress of the shingle is here first arrested by the Isle of Portland, owing to the projection of that point of land in a line some¬ what to the westward of south, and the shingle bank stops just where the land trends in a south-west direction. “ The Chesil Bank, at that part of it nearest the Isle of Portland, is from 20 to 30 feet above the ordinary high-water mark. On the west side it is steep, and the water deep close to the shore; but on the east side it has a gentle slope, with a base of 200 yards, to the above height of 20 or 30 feet. 419 SHINGLE. SHI “ This gentle slope on the east side is owing to the accumulation of water on the opposite side during westerly gales, which finds a passage through the gravel bank, washing it into little ravines, and carrying down stones by its current. In very severe storms the sea washes over this bank; and it did so on the 23rd of November, 1824. “ A dangerous shoal of coarse sand, called the Shambles, which lies off the south-east point of the Isle of Portland, is in all probability formed by the tides; but the Chesil Bank is formed by the waves break¬ ing on the shore in south-west gales; and it is important that these two causes, and their resulting conse¬ quences, should always be sepa¬ rately considered. “ Siliceous or very hard pebbles only withstand long rolling on the beach, whilst calcareous stones soon become ground into sand. As the siliceous pebbles do not pass round Portland Island, sand only is found on the shore of Portland Roads; and it is calcareous, effer¬ vescing strongly with muriatic acid. “ Scarcely any gravel is to be seen between Portland Roads and Weymouth. Within the ‘ Aberga¬ venny,’ an East India ship which sank thirty years ago in the mouth of Weymouth Bay, there is no gravel, and very little sand. East of Weymouth it again begins to collect; but each little headland, acting as a groin, retains much of it in the small hays. Round St. Alban’s Head its action has not been observed, but at Christchurch the quantity is considerable, and at Hurst Castle it is very large. “ The Isle of Wight, and the strong current running through the Needles, here again a second time stop its eastward movement; and it forms, nearly in the mid-channel, a shoal called the Shingles, the easternmost end of which (by the action of the westerly winds on one side, and the current of the Needles SHI on the opposite) becomes heaped up above high-water mark into an j island, varying in shape and size ' with every storm, and sometimes i disappearing altogether. “ The pebbles coming from the i westward must be driven across the north channel to this bank; but j they do not pass across the south and principal channel of the Needles to the Isle of Wight, as is evident from local inspection ; for those of the Isle of Wight are of a different colour, being black flints from the chalk, whereas those on the side of Hurst Castle are generally yellow. “ The effect of the prevailing wind, in driving the gravel along the coast from west to east, is not less evident on the south of the Isle of Wight than elsewhere. It passes eastward until it reaches Sandown Bay, wdiere the artificial groins, kept up at considerable cost, arrest a certain portion; but the surplus is poured over these groins, and, falling on the east side, continues its course. “ The gravel which passes Ports- i mouth does not appear to come >: from the westward of Hurst Castle, for the shores just within the Needles are mud without stones. A new system commences within the Solent. A large quantity of shingle is furnished from the gra¬ velly soil of the south coast of Hampshire; and this shingle is likewise driven eastward, some¬ times returning westward when easterly winds prevail, but the ba¬ lance of its progress is always to¬ wards the east. “ Hurst Castle, Calshot Castle, and Blockhouse Fort, Portsmouth, all stand on similar tongues of shingle, formed on the west sides of their respective passages by the prevailing westerly winds. “ At Hurst Castle the gradual additions to the end of the strip of shingle may be plainly seen; for Nature there records her own his¬ tory in a very visible manner. An 420 SHINGLE. SHI ordnance landing-place, 30 feet long, which was constructed in 1806, and stood in the sea, became en¬ tirely buried in gravel; and many succeeding lines of high-water mark may be distinctly traced to the eastward of Hurst Castle. “ Similar traces of many former lines of high-water mark are also to be seen near Southsea Castle; and immediately on the west of Fort Monkton, six distinct lines of high water maybe counted; and some of these probably belong to very remote periods of time. “ The direction of the line of coast, with reference to the pre¬ vailing gales, seems to determine where the shingle will accumulate, or where the sea will be most likely to encroach upon the land; and seems to be one of the most im¬ portant points to study as regards the subjectof openingbar-harbours. “ The south-easterly direction of the beach at Southsea would appear to be one of the causes why the entrance of Portsmouth Harbour is SHI kept as clear as it is, by the current running out of it; for this direction of the land prevents the w r ater from spreading itself on both sides, at the ebbing tide, as it does at the entrance of Langston Harbour, over banks of gravel; and this direction at Southsea appears just sufficient to allow the shingle to be set to the eastward by the prevailing gales. “ It well deserves consideration, whetherembankments (on the south coast of England) run out on the eastward of bar-harbours, in a line parallel to the line formed by nature on the east side of Portsmouth Harbour, would not lead to a simi¬ lar effect as that produced there by keeping open one principal channel. By a proper system of groins on the west side of such harbours, shingle coming from the westward would be stopped, and much of the ma¬ terials which now form the bars might be arrested in ther course. “ The slope of the beach is flatter after a southerly gale, and its aver¬ age slope is about 1 foot in 9. Foot of the slope of gravel. “ If groins are not carried far enough in-land, the sea in south¬ west storms (on the south coast) will break round and insulate them. If they are not high enough at high-water mark, the gravel w'ill be carried over them to the east¬ ward ; and if they are too short, it will pass round the outer end of them. “ During southerly gales, it is frequently said, that the gravel is 421 SHI SHINGLE. SHI ‘ carried into the sea,’ because the receding waves draw it down ; but it is again driven back, and if the wind is south-wesl> it is set to the eastward. “ The preceding figure, in which a pebble ( a ) passes to ( g ), fol¬ lowing a course indicated by the alphabetical order of the letters, will explain what is here meant, and show the way in which the gravel passes by groins which are too short. “ From this figure it will also be understood, why a single plank re¬ moved from a wooden groin will cause the beach at such place of removal to be carried on forward ; and hence the importance of con¬ structing groins of materials not liable to such accidents. “The point of shingle on which Calshot Castle now stands was once an island, and called, in 1717, Crown Island; since which time the opening has filled in with gra¬ vel. The point on the west side of ChristchurchHarbourisnow length¬ ening annually ; and the mouth of that harbour and its bar become every year more and more removed to the eastward, and if left to na¬ ture may continue to be removed eastward until the water from that estuary shall re-open a fresh pas¬ sage for itself in a more direct line, as the water seems to have done at the harbour of Shoreham. “ At such harbours as Ports¬ mouth it would be desirable, by means of the apparatus for enabling persons to descend and examine the bed of the sea, to observe and determine the precise mode of the action of the shingle at the entrance of harbours. “ The sand being blown by the wind, as well as driven by the surge, it frequently covers the coarser shingle, where it is re¬ tained by the carex arenaria, a grass which roots at every joint.” (Much valuable information on the subject of encroachments of the sea upon the land will be found in Lvell’s ‘ Geology.’) 422 SILT. SHI SIL Shingles, in house-building, small pieces of wood sawed to a certain scantling, used in roofing, instead of tiles or slates. Shittim wood, a valuable kind of tim¬ ber, of which Moses made the greater part of the tables, altars, and planks, belonging to the taber¬ nacle : it grows in the deserts of Arabia, and is like white-thorn in its colour and leaves, but not in size, as the tree is so large that it affords very long planks: the wood is hard, tough, smooth, without knots, and extremely beautiful; so that the rich and curious make screws of it for their presses. Shivers, in navigation, the little round wheels, of wood or metal, in which the rope of a pulley or block runs. Shales, pieces of plank put under the shores where there are no ground- wavs. Shores, pieces of timber fixed to sup¬ port a ship. Shrines, tombs, or decorated monu¬ ments of ornamental tabernacle- work, as they are applied to the entombment of royal and noble persons : several very fine examples exist in the cathedrals and abbey churches : the term is also applied to a cabinet in which sacred things are deposited. Shunt, a term applicable to the ma¬ nagement of railway trains, to re¬ move a carriage or train off the main 1 line. When an engine, carriage, or , train is moved off the main line j to a siding, it is then said to be ‘ shunted.’ It is most probably de¬ rived from the word ‘ shun in the old English Romance ‘ Mort d’Ar- thur’ we find the w T ord ‘schunte’ j used in this sense, to put off; and in other early works the word ‘ shunted’ may be found, with the meaning, to move from. Side chains, chains and hooks fixed to the sides of the tender and en¬ gine for safety, should the central drag-bar give way. Sidereal year, that space of time 423 which astronomers compute the sun is moving from any fixed star till it returns to it again, reckoned at 365 days, 6 hours, and almost 10 minutes. Sienese School, the school of a lively people; and is so agreeable in the selection of the colours and the air of the heads that foreigners are cap¬ tivated, and sometimes even prefer it to the Florentine. But there is another reason for this preference, viz. the choicest productions of the Sienese painters are all in the churches. In Florence it is other¬ wise ; no picture of Vinci, of Buo¬ narroti, of Rossi, is to be seen in public; none of the finest produc¬ tions of Andrea or of Frale, and few of the other best masters. The ac¬ counts of the early Sienese painters are confused by the plurality of the Guidi, the Mini, the Lippi, the Varni (abbreviations of Gia¬ como, Filippo, Giovanni). To sum up, the character of the School is not so original as some others, and during its best time some of its artists imitated the style of others. Some of the greatest modern names are Giantonio Razzi, surnamed II Sodoma, b. 1479, d. 1554; Do¬ menico Beccafumi, called Meche- rino, b. 14-84, d. 1549 ; Baldassare Peruzzi, b. 1481, d. 1536. Signal lamps, railway lamps, with a bull’s-eye glass in front. Each lamp has a recess between the burner and bull’s-eye, for dropping ' in any particular coloured glass, according to the light which is to be shown. The lamp has also re¬ cesses for holding these glasses, so that the engineman can at once pick out a red, green, or blue glass, and put it in front as he may re¬ quire it. Sill, the lower horizontal frame of a door or window; a threshold. Silt, in hydrography, etc., mud depo¬ sited by rivers, tides, etc., generally in still parts or eddies, and also in lakes or hollows filled with still water. t 2 SIPHON. SIL SIP HON. SIF 1 Silver is sometimes found in the me¬ tallic state, and as chloride and sulphide, besides alloyed with gold, copper, and other metals. It is a pure white brilliant metal, of great ductility, capable of being drawn out into very fine wires. It melts at 1873°, and absorbs a large quantity of oxygen, which, disen¬ gaging on cooling, gives it a white, frosty appearance: when impure, it does not do so. It is a metal used in great abundance as a coin in all countries, also for plate, for vases, candelabras, cups, etc. Sinking, in mining, digging down¬ wards ; in rising and sinking a shaft, one set of men sink from a certain level, while another set rises from a lower level to meet them. Siparium, in the time of the Romans, a piece of tapestry stretched on a frame, which rose before the stage of the theatre. Siphon, or Syphon , in hydraulics, a crooked pipe through which liquors are conveyed. Siphon. The date of the first appli¬ cation of the principle by which water or other fluids may be drawn from one level to another by the exhaustion of the air contained in the limb communicating with the lower level, appears to be very remote. The Egyptians certainly used it for the transvasing of wine : but the first important application of this principle to useful or general practice was in the aqueduct wdiich conducted the springs of Mount Pila to Lyons: the date of this aqueduct is about 40 years after the commencement of the Christian era. Upon the total length of the aqueduct, which with its branches was 15 old French posting leagues, there were three large siphons to carry the water from the upper sides of the same number of valleys to the lower. Of these, the valley of Chaponest was 2400 feet across, measuring in a straight line across the valley; and it was about 200 feet deep. The valley of St. Foy was about 3,192 feet across, by 3001 feet deep; that of St. Trence was" 798 feet across, but much shal-l lower. The pipes of the Chaponest si-h phon, on leaving the upper reser- voir, were 8 inches diameter and ( 1 inch thick: they were of lead. After running 75 feet of the descent of this dimension, they branched off into two divisions of 6 inches diameter each, in order that the pressure upon the pipes at the lower portion of the siphon might be diminished. They ran over the level bridge in the lower part of the valley of this smaller diameter, and mounted the opposite side for a height of 70 feet, when they re¬ united into pipes of 8 inches dia¬ meter again. The total fall of the Chaponest siphon was 150 feet, the rise on the opposite side was 130 feet, leaving a difference of level of 20 feet to compensate for the friction. The Siphon of St. Foy had a difference of level, from the upper reservoirs to the straight part, of 240 feet. The Lyons aqueduct had in its total length thirteen common straight aqueduct bridges and three siphons; it delivered very nearly 1,300,000 gallons in the twenty- four hours. , Many writers on hydraulics have failed to notice these extraordinary works, and have expressed their surprise that the ancients were ig¬ norant of the existence of the law by which water finds its own level. The ancients, however, appear to have wisely preferred the more economical system of carrying water in a straight trough, where- ever the expense was justifiable. Waterworks were, in early times, Government affairs, and the ex¬ pense of their maintenance was de¬ liberated. The preceding cases abundantly prove that the ancients applied the well-known law of liy- drostatical balance whenever they found such a course advisable; and 424 SIP SKIRLAW. SKI the details given by Vitruvius re¬ move all doubt upon the subject. His instructions (lib. 8, c. 7) are as follows :—“ When the expense of erecting a bridge is too great, a siphon may be used; but this should only be resorted to as a last expedient. The danger of bursting the pipes, and the expense of the repairs, are serious objec¬ tions to this method, and in the end straight bridges are the cheapest. If, however, it be determined to employ a siphon, it should be laid with a regular curve, and all abrupt elbows avoided. To secure this, a substructure should be raised to fill in any inequalities in the valley where it is to be erected. The last length of the descending pipe and the first of the straight pipe at the level part, as also the last length of the straight pipe and the first ascending one, should be let into a solid stone, which should be carefully fixed and surrounded with ballast, properly rammed.” He also gives directions for the construction of air-shafts from the lower parts, which he calls ‘ co- lumnaria,’ and he expressly states that they are necessary to relax the ‘ vis spiritus in ventris,’—the force of the air in the curves. Siphon-cups, in steam-engines, cups placed for feeding oil to the work¬ ing parts of the machinery, trim¬ med with cotton or worsted, the same as the axle-boxes. Sissoo is one of the most valuable timber-trees of India, and with the saul is more extensively used than any other in north-west India. The ship-builders in Bengal select it for crooked timbers and knees; it is remarkably strong; its colour is a light greyish-brown with dark- coloured veins. Spindletree, a shrubby tree, with a yellow wood similar to the English boxwood: it is turned into bobbins and common articles. Site, the situation of a building; the plot of ground on which it stands. Site, in landscape, signifies the view, prospect, or opening of a country, derived from the Italian word sito, situation ; and it is in use among painters, as being more expressive. Sketch, a slightly-made picture, in which the general effect is attended to, but not always the details, and from which more finished works are painted: so also with sketches in architecture, giving the correct outline of a building without filling up with the detail. Skew, or Askew, as applied to masons’ work, an oblique arch. Skirlaw, Walter, when prebend of Fenton, in 1730, took down the middle tower of York cathedral, built by John Romanus, and built the present noble tower in its stead, at his own expense. It was built in six or seven years. “ Walter ap¬ pears to have been a munificent prelate, and an architect of uncom¬ mon genius. The tower above-men¬ tioned would have been sufficient to establish this character; but that part of Howden Church, about 18 miles from York and Beverley, shows a richness of fancy and de¬ licacy of taste equally adapted to smaller structures. The Chapter- house struck me as eminently beau¬ tiful. A small chapel built by him, called Shinlaw Chapel (which I believe is the name of the village), is wnrthy of attention for its chaste and elegant style. It is a few miles from Hull and from Beverley. All these I have seen, and can speak of them confidently. Walter Shirton was made Bishop of Lichfield and Coventry, then of Bath and Wells, and afterwards of Durham, where he continued seventeen years. He built the bridges of Shinkley, and Auckland, and Yar¬ row ; also a chapel at Swine, in Holderness (Query, is not this the chapel above mentioned, which is called Skirlaw Chapel ?), where he was born. He built also the steeple of Holme, and repaired the church and manor there” (Gent). He be- 425 SKI SLIDE-REST. SLI , stowed above .£800 (a large sum in those days), while Bishop of Dur- I ham, towards building the dormitory I and cloister of the monastery in that I city, and left several sums of money to the churches he had governed, ! particularly to that of Wells, to buy ornaments for the decent perform- j ance of divine service. He was | buried in the cathedral of Durham, southward of the choir. From the epitaph we learn that he died 24th March, 1405. Under this prelate Gothic architecture seems to have attained its highest excellence. { Skirting, a narrow board forming a plinth to an internal wall. Skreens were either of needlework or painted: in the time of Henry VIII. is noticed a skreen as a new year’s gift from Luke Hornebound, a painter, to that monarch. Skylights, glass frames placed in a roof with one or more inclined I planes of glass. Slaking of Lime. Quick-lime, taken as it leaves the kiln, and thrown into a proper quantity of water, splits with noise, puffs up, produces a large disengagement of slightly I j caustic vapour, and falls into a j thick paste. So much heat is pro- { duced in slaking, that part of the j water flies off in vapour. If the I quantity of the lime slaked be great, the heat produced is suffi- j cient to set fire to combustibles: \ in this manner vessels loaded with lime have sometimes been burnt. When great quantities of lime are slaked in a dark place, not only ! heat, but light also, is emitted. The specific gravity of pure lime is 3-08. Slate, an argillaceous stone, readily- split, and employed to cover build¬ ings, and also for other purposes : it is quarried in large pieces. Slating is employed by builders for covering in the roofs of buildings. The slates principally in use in Lon¬ don are brought from North Wales. Sleepers, pieces of timber employed to support others, and laid asleep, or with a bearing along their own i length : sleepers denote more par¬ ticularly those timbers which are I placed lengthwise on walls to sup¬ port the joists of a floor ; they are employed on railroads as longitu -1 dinal bearings for the rails to rest j upon. Sleepers, or Tramome-knees, are fixed j j withinside a ship abaft, one arm i laying on the foot waleing, and the : I other extended up the transoms. Sliekings, narrow veins of ore. Slide, a vein of clay, which, intersect¬ ing a lode, causes a dislocation ver-! tically. Slide-rest. This apparatus, the in- J vention of Mr. Henry Maudslav, is | of the utmost importance for per -1 fecting and accelerating the con -1 ! struction of machinery. Before j its invention, cylindrical turning I was a work of manual labour, and was attended with so muth diffi- I culty and expense, when the cylin- I ders were either large in diameter or of moderate length, that it was necessary to avoid using them in many cases; and plane surfaces being even still more expensive, in consequence of the very imperfect; and laborious operations of chipping J and filing them, many very valuable ; - inventions could not be carried into effect on account of the inaccuracy and expense attending their con¬ struction. The invention of the slide-rest, forming an all-important part of that of the planing machine, has entirely removed both of these difficulties, and cylindrical turning and planing are now' the cheapest and most perfect of mechanical operations. The office of the slide-rest, as! applied to lathes and turning ma¬ chines, is to hold, engage, and direct the turning-tool, and it may be kept i in motion either by hand or by self¬ acting machinery. When applied to a small lathe, I it is generally moved by hand; but in large machines for heavy j work, where the time of action is 426 SLIDE-VALVE. SLI SLI considerable, it is moved by ma¬ chinery attached to the lathe. The work to be turned being placed in the usual way between the two centre pieces of the lathe, the lower part of the slide-rest is fixed under it on what is called the bed of the lathe : the use of this part of the slide is to move the tool to or from the work, which it effects by means of a slide, at right angles to the work, moved by a screw and handle: this s de has fixed upon it, by a swivel joint, the upper part of the apparatus. The upper part has also a slide [ moved by a screw and handle, and | generally placed at right angles to i the lower slide: the principal use of this upper slide is to move the i cutting-tool which is fixed upon it ; parallel to the centre line of the Fig. i. t lathe; but it can be so placed, by aid of the swivel-joint, as to cause the tool to advance at any required angle with the centre line of the lathe. Thus two direct movements are obtained: the first to set the tool to the work, and the second to move it either to the right or left, in a line parallel with the work, or at any given angle with the first. The slide-rest principle enters largely into the construction of all kinds of machinery, from the most minute to machines of vast magni¬ tude, where by its aid ponderous masses—such, for instance, as rail¬ way turn-tables 36 feet in diame¬ ter—are operated upon with a precision unattainable by any other means. 1 Slide-valve, in locomotive engines, the Fig. 2.. Fig. 3. 427 SLI SLIDE-VALVE. valve placed in the steam-chest to work over the steam-ports. It regulates the admission of steam to the cylinder from the boiler, and the escape of the steam from the cylinder to the atmosphere. Its form is that of an arch in the centre, with a flat face all round to keep it steam-tight on the face of the steam-ports. It is by the arched part that the steam escapes to the atmosphere. It is a very simple valve, and answers its pur¬ pose well, with one drawback, namely, the pressure of the steam upon it being unbalanced by any counter-pressure. Numerous at¬ tempts have been made to relieve this pressure, some of which it is hoped will be successful. In sta¬ tionary engines the contrivances differ materially, as shown in the woodcut, Figs. 1, 2, 3. Fig. 1 represents in section the cylinder, piston, arid slide : S is the mouth of the steam-pipe coming from the boiler ; e is the pipe lead¬ ing to the condenser; t is the rod which is attached to the slide, moving through a stuffing-box, m n. This slide is represented’in longi¬ tudinal section, separately, in fig. 3, and in transverse section in fig. 4. In the position of the slide repre¬ sented in fig. 1, the steam passing from the boiler enters at S, and passes to the bottom of the cylin¬ der through the opening b, where it acts below the piston, causing it to ascend. The steam which was above the piston escapes through the opening at a, and descending through a longitudinal opening in the slide behind the mouth of the steam-pipe, finds its way to the pipe e, and through that to the condenser. When the piston has reached the top of the cylinder, the slide will have been moved to the posi¬ tion represented in fig. 2. The steam now entering at S passes through the opening a into the cylinder above the piston, while SLI the steam which was below it es¬ capes through the opening b and the pipe e to the condenser. Fig. 4. The form of the valve, d t from which it derive* its name of D-valve, is represented in fig. 4 . The longitudinal opea- ing through which tl* steam descends then d e appears in section of a semicircular form. The packing »t the back of the slide is represented at this is pressed against tlie surface of the valve-box. Slide-valve lap. Outside, in locomotive engines, that portion of valve which would overlap the steam-portsw het; placed over them. If the steam, ports measure 8 inches overall the ports, and the valve be 10 inches i broad, this would be an overlap of 1 inch on each side of the ports, j t and is called the ‘ lap’ of the valve. ] Expansion was formerly regulated by the extent of lap only, but it is now regulated by both the lap and the expansion gear, which gives greater scope in doing so. Inside lap is the portion of the valve-face which would overlap the inside of the steam-ports when placed over them ; for if the steam-ports were 4 inches from inside of the one port to the inside of the other J port, and if the arched part of the valve only measured 3|- inches across, this would give of an inch lap on each side, which is I called inside lap. Slide-valve lead, in locomotives, the width which the steam-port is opened by the slide-valve when the piston is at the end of the stroke. It varies from ^ to £ an inch, accord¬ ing to the work required. The lead is obtained by fixing the eccentric on the axle, a little in front of the crank, by which arrangement the steam-port is opened in front of the direction in which the piston is moving before the latter has completed its stroke. By these means the steam-port is thrown 428 SLI SLIDE-VALVE. SLI quickly open when the piston com¬ mences its return stroke, and has at once the full pressure of the I steam against it. Slide-valve travel, the distance which the slide-valve travels in one direc¬ tion for each stroke of the piston. | This is from 4 to 5i inches gene¬ rally, hut is reduced by each varia¬ tion of the expansion gear, and its travel is taken for both the front and back strokes of the piston for each notch where the handle is fixed. The up-and-down quarter- | revolutions of the crank do not j equally draw the piston the half- j length of the cylinder, and this I and the expansion gear so far affect the working of the slide, that it is necessary to take the front and back stroke working separately. Setting the slide-valve: the ec¬ centric is brought as much before the crank as to give the required lead to the slide-valve when the crank is on the centre, that is, in a straight line with a cylinder. The handle is then moved to each sepa¬ rate notch, and the position of the slide and piston carefully taken for each variation. These are then re¬ corded in the following manner :— Slide-valve and Piston Motions’ Register .— Working of expansion gear. _ Engine, _ _185 Inches. Inches. Diameter of cylinders . . 18 Outside lap of valve . . 1 Length of stroke .... 24 Inside lap of valve . . . 1 32 Size of steam-port . . . 15 x 2 Size of exhaust-port . . 15 x 1 ! .si Steam cut off. Exhaust opens. Compres¬ sion begins. Steam-port opens. REMARKS. Vs z-g © «*-. > ° Is £ | « o © M 2 c -*■» c © M o . « o © 2 e •«_o © ’o . to o © 2 a « 5 © o . x O © 2 P o o . u 93 © P- © ’P- ° j= o ic z.s © 'T II "S-S © .- J c •- o — £ o ^ ■* o — »'c o o •g'S. a'c O o T; P- rt . 33 o G ’G O £ o '© P. ir CQ o S .5 J G 3 Balancepiston for slide- valves. • In. In. In. In. In. In. In. In. in. In. In. 1 H i i 3 2 19* 19 221 22f 22i 22-K 4 if H 2 H 3 1 32 18* 18 22* 211 22 21-i 8 i* * 99 3 4 1 1 32 16# 16* 21f 211 2H 21 1 5 1 0 1* 99 4 H 1 3 32 131 134 20* 19* 20 191 1 1 1 3 1 6 99 5 H 1 1 32 H 10 18* 18* 18 17* 9 3 t> 9 1 fi 99 Centre notch. i 6 2 U 1 1 3 2 3* 6 151 15 151 151 , i 32 1 1 32 99 The above measurements are carefully taken and registered by the mechanic who sets the slide-valves. SLI SMELTING. SME Slide-valve rod guide, in locomotive engines, a bracket fixed to the boiler, the lower end of which is fitted for the slide-valve rod to work through. A set-screw is use¬ ful in this guide for fixing the rod when the valve has to be discon¬ nected. Slide-valve rod and frame, in loco¬ motive engines: the frame is fitted on to the top part of the valve, and the rod connects the frame with the slide-block, or rocking- shaft, according to the description of valve-gear of the particular engine. Slide-valve motion, in locomotive en¬ gines, a short motion similar to the piston-rod motion, connecting the quadrant to the slide-valve by parallel guides. Sliding rule, a rule constructed with logarithmic lines, formed upon a slip of wood, brass, or ivory, in¬ serted in a groove, in a rule made to slide longitudinally therein, so that by means of another scale upon the rule itself the contents of a surface or solid may be known. Slimes, mud containing metallic ores, mud or earthy particles mixed with the ores. Slit deal, a name for inch and a quar¬ ter-inch deal cut into two boards. Sloop, in navigation, a small one- masted vessel, the mainsail of which is attached to a gaff above and to a long boom below. The word is also applied to any small ship. Sluice, in hydraulics, a water-gate, a flood-gate, a vent for water. Smelting, is the process of separating metals from the earthy and other matters with which they are com¬ bined in the state of ore. Of this operation, as conducted upon the ores of iron, copper, lead, and tin, the following is a brief description. Smelting Iron . The reduction of iron ore is effected in a furnace in which, the required intensity of heat being obtained by a current of air driven rapidly into the furnace, has received the name of a blast¬ furnace. The kind of furnaces em¬ ployed, the quantity of ore or mine, as it is termed, reduced at each heat, and the peculiar method of conducting the operation, vary widely in different countries and counties, and have some reference in detail to the precise quality and composition of the ore to he treat¬ ed. Previous to the year 1740, the smelting of ores of iron was, in England, performed solely with the charcoal of wood, the ores operated upon being principally the brown and red hematites, or rich ores, that is, containing alarge proportion of metal with a 6mall quantity of earthy materials. In the treatment of this class of ores, it may be ob¬ served that very little improvement has yet been effected, the modern process having been chiefly ap¬ plied to the leaver ores, such as blackband, etc. The expensiveness and comparative scarcity of char¬ coal as a fuel for the smelting of iron ores, induced those engaged in the art to attempt the substitution of coal for wood-charcoal; and by the year 1788, these attempts had so far succeeded, that there remain¬ ed only 24 out of 59 charcoal fur- nacles, while 53 furnaces had been established in which coal, burned into the form of coke, was used for the smelting of the ore. Since that date, the extension of this process has proceeded rapidly, and the total quantity of metal produced has experienced a corresponding augmentation. At the present time, the Backbarrow Iron Company are nearly the only smelters of iron with wood-charcoal in the kingdom. The two principal seats of the iron manufacture in Great Britain are in Staffordshire and South Wales. In the former district, comprising the neighbourhoods of Dudley, Bilston, Wednesburv, etc., the smelting or blast furnaces are constructed al¬ most wholly of bricks. They are usually of a conical form exter- 430 SMELTING. SME nallv, and sometimes pyramidal, the plan being a square or rectangle. In the interior they are mostly cir¬ cular in form, except in that part called the hearth. The fuel and the ore to be smelted are fed into the furnace from the top, and its height being from 40 to 50 feet, an ascendingplatforrn orinclinedplane is constructed for wheeling up the barrows in which the materials are conveyed. The p : pes through which the air is driven into the furnace (by a steam-engine) are called the tuyeres, and are usually two, hut sometimes three iu number. The relative quantities of coal, iron¬ stone, and limestone, which are put into the smelting furnaces of Staffordshire for the production of each ton weight of iron produced, are about 50 cwt. of coal, 50 cwt. of mine, previously calcined, and from 12 to 16 cwt. of limestone, the latter material being added as a flux to promote the fusion of the mass. The Conegree furnace, near Dudley, may be instanced as a good example of a blast-furnace adapted for the economical smelt¬ ing of iron ores. It is 54 feet in height, 5 feet in diameter on the hearth, and 12 feet above, widening upward to a diameter of 13 feet 9 inches, and reduced to 8 feet above the platform, on which the charges are delivered. The quan¬ tities of materials employed in this furnace to make one ton of pig- iron, are of coal 2 tons and 5 cwt., i or of coke 37 cwt., charred mine i 2 tons 5 to 10 cwt., limestone 13 to 16 cwt. Each charge delivered into the furnace consists of 9J cwt. of coke, 12 cwt. of charred mine, and 4 cwt. of limestone. At this furnace 115 tons of pig-iron have been made in one week. The cylinder from which the air is blown through the tuyeres into the furnace is 72£ in. ■ in diameter, and the stroke is 7 feet in length. Originally there wrnre five tuyeres for the introduction SME of the blast, one muzzle being 2£, two others 2J, and the other two 2 inches in diameter. Subsequently these were changed to four muz¬ zles, of the respective diameters of 3£, 2£, 2£, and 2 inches. Smelting Copper. Copper ore, as smelted in SouthWales and other places, usually consists of pyrites (composed of sulphuret of copper and sulphuret of iron in nearly equal proportions) and vein-stone. The earthy matters combined with the pyrites are commonly siliceous, and the process of smelting consists. in alternate roastings and fusions. The first of these operations is, cal¬ cining the ore in furnaces in which the heat is applied, and increased gradually, till the temperature be as high as the ore can support | without melting or agglutinating, when the ore is thrown into an arch formed under the sole of the furnace. The second operation, or fusion of the calcined ore, is per¬ formed in a luted furnace, the ore having been spread uniformly over the hearth, and fluxes, such as lime, sand, or fluor-spar, being added when required, although the ne¬ cessity for this addition is sought to be obviated by a careful admix¬ ture of ores of different qualities, the several earthy components of which shall serve as fluxes in the fusion of the mass. These two processes of calcination and fusion are completed alternately until the ore is completely freed from all the earthy materials, and pure metal is obtained. Smelting Lead. The ores of lead, after being sorted, cleansed, ground, and washed, are roasted in furnaces, which are without any blast or blowing apparatus, the ores being separable from the metal by its great fusibility. Several of the furnaces are usually connected with one chimnev-stalk, to which a series of flues about 18 inches square conduct. The melted lead runs freely from the ore, and is 431 SMO SMOKE. drawn off into the moulds in suc¬ cessive quantities, the ore being repeatedly turned over, and a small quantity of coal added over the burning mass at each drawing. Smelting Tin. This process con¬ sists of the calcining or roasting of ! the ores after they have been clean¬ ed, sorted, stamped, and washed. The calcining is performed in a re¬ verberatory furnace from 12 to 15 feet long and 7 to 9 feet wide. The hearth of these furnaces is hori¬ zontal, and they have only one opening, which is in the front, and j closed by an iron door. The sul¬ phureous and arsenical vapours which arise from the ore are con¬ ducted by chimneys over the doors of the range of furnaces into hori¬ zontal flues, in which the acid is condensed. In the process of cal¬ cination, which occupies from 12 to 18 hours, according to the quan¬ tity of pyrites contained in the ore, 6 cwt. of ore are treated at once, and the materials are stirred from time to time, to prevent them from agglutinating. Smoke, Prevention of. There is per¬ haps no subject so difficult, and none so full of perplexities, as that of the management of a furnace, and the prevention of smoke. Mr. Fairbairn, in his report to the Bri¬ tish Association on the Combus¬ tion of Fuel and the Prevention of Smoke, observes :—“ I have ap¬ proached this inquiry with consi¬ derable diffidence, and after re¬ peated attempts at definite con¬ clusions, have more than once been forced to abandon the inves¬ tigation as inconclusive and unsa¬ tisfactory. They chiefly arise from the constant change of tempera¬ ture, the variable nature of the vo¬ latile products, the want of system, and the irregularity which attends the management of the furnace. Nevertheless, the prevention of smoke and the perfect combustion of the fuel, are completely within the reach of all who choose to 432 SMO adopt measures calculated for the suppression of the one and the improvement of the other. “ On presenting to the British Association an inquiry into the merits of Mr. C. Wve Williams’s Argand furnace compared with those of the usual construction, it was found from an average of a series of experiments, that the saving of fuel (inclusive of the ab¬ sence of smoke) was in the ratio of 292 to 300, or as 1 : l - 039, being at the rate of 4 per cent, in favour of Mr. Williams’s plan. Since then a considerable number of experiments have been made by Mr. Heuldsworth, Mr. Williams, and others, which present some curious and interesting phenomena in the further development of this subject.” When these trials were made many of the details of the construc¬ tion of furnaces were but imper¬ fectly understood and applied, and hence the amount of economy was far short of what has since been realized. Among the more recent experiments, as illustrative of the practicability of effecting perfect combustion of the fuel employed, may be mentioned those made by Sir W. Armstrong, Dr. Richard¬ son, and Mr. Layridge, to whom the inquiry was entrusted by the Colliers’ Association of Newcastle. Of these trials an ample report was made, and has since been pub¬ lished, which will well repay ex¬ amination. Sufficient information is there given of the requirements of furnaces, and the practical de¬ tails of their relative proportions. These competent judges in this case decided in giving preference to the principles and practice adopted by Mr. Williams, stating their unanimous opinion “That Mr. Williams must be declared the successful competitor, and there¬ fore award him the premium of £500 offered by the Association.” In their Report they state as an SMOKE. SMO SMO KE. SMO important feature of the success¬ ful plan, that “ It may be applied under varied circumstances, pro¬ ducing a more complete absorption of the heat generated, with a great increase in the economic value and work done.” In this respect the practical result was as near the theoretic value of the fuel, as per¬ haps will ever be effected. Mr. Williams’s plan, independent of the details of the furnace, re¬ lied on the introduction of the re¬ quired quantity of air through se¬ veral hundred half-inch orifices in¬ serted in the door-box, and above it. As the entire question of the proper combustion of the fuel depends on the admission and ac¬ tion of the air, it may here be use¬ ful to state that each ton of bitu¬ minous coal produces, on an aver¬ age, 10,000 cubic feet of gas ; and further, that each cubic foot of this gas requires for its combustion 10 cubic feet of air at atmospheric tem¬ perature. That this is independent of the quantity required for the combustion of the coke portion of the coal, and which is estimated at double the quantity required by the gas. Thus, then, 100,000 cu¬ bic feet of air are absolutely ne¬ cessary for the combustion of the . gas alone of each ton of coal, and 200,000 for the coke of the same ton weight. On the question of quantity, then, there is no doubt or difficulty. | The next point for consideration is as to the place and mode of introducing this large quantity of air, so that the necessary admix¬ ture of the air and the gas may be effected. On these points Mr. Wil¬ liams, in his treatise on the com¬ bustion of coal, states :—“ With reference to the place for the ad¬ mission of the air, it is a matter of perfect indifference, as to effect, in what part of the furnace it is introduced, provided the all-im¬ portant condition be attended to, namely, that the mechanical mix- ture of the air and the gas be con¬ tinuously effected before the tem¬ perature of the carbon of the gas (then in the state of flame) be reduced below that of ignition; this temperature, according to Sir H. Davy, being 800°. With reference to the propor¬ tion' of the several parts of a fur¬ nace, it has been practically ascer¬ tained that in the chamber of the furnace there should never be less than 2 feet between the bars and the crown-plate. That an ade¬ quate space of at least double the area of the furnace be appropri¬ ated behind the bridge as a com¬ bustion chamber, in which the process of mixture and chemical union may be effected. Further, that there should be a distance or run between the furnace and the tubes, if any, of not less than ten Wet lineals in which the process is continued. In the experimental furnaces at the Newcastle trial, the area of ad¬ mission for the air was equal to 4 inches square for each square foot of grate-bars. The prevention of smoke is so directly connected with the con¬ struction of boilers, as to render it necessary to refer to the plan now almost universally adopted, namely, the multitubulous plan. On this point there is a great diversity of opinion among engineers. By nu¬ merous improvements made by Mr. Williams, Mr. Dewrance, and others, it has been ascertained that the value of the tubes as heat¬ absorbing surface has been greatly overrated. It appears, practically, that with the exception of the first 12 or 24 inches of the tubes, the remainder have very little steam¬ generating effect, and that as a general principle the effective heat¬ ing surface of tubes should only be estimated at one-tenth of their su¬ perficial area. That when coal is . used the tubes are seriously pro¬ ductive of smoke, and its accom- 433 SMO SNAKE WOOD. paniment, soot. Considerable at-, j tention has been given of late to this point, since the economy in I the use of coal instead of coke in j locomotives has been so fully as- J certained. With the view of avoid- i iug the nuisance of smoke in lo¬ comotives, their construction has ! of late been much modified. The i necessity for a second, or com¬ bustion chamber, is now gene¬ rally admitted, thus assimilating their construction to that of ma¬ rine boilers, as already described. So insufficient has been the effect of tubes as steam generators, and so injurious are they in the gene¬ ration of smoke, that an impor¬ tant change will no doubt short¬ ly take place. It is even now found by successful practice on the London and North-western Railway, that while the combus¬ tion-chambers are much enlarged, the tubes .are no more than 22 inches in length. More recently Mr. C. Wye Williams has proved his complete success in the accom¬ plishment of all that can be de¬ sired ; his prize at the Society of Arts, and the award of .£500 by the Newcastle Association, are proofs of liis superiority over his compeers. Smoke-lox, the end of the boiler on which the chimney is placed. Loco¬ motives with inside cylinders have them placed in this box, which keeps both them and the steam- pipes at a high temperature. Smoke-box door, the door in front of the smoke-box, by which access is j gained to the cylinders or steam- pipes, and other parts placed in this box. Snake wood, a kind of speckled wood used in Demerara, Surinam, etc., for the bows of the Indians : the colour of the wood is red hazel, with numerous black spots and marks, which have been tortured into the resemblance of letters, or the scales of reptiles. When fine, it is very beautiful, and is scarce in SOL England : chiefly used for walking-1 sticks, which are expensive. The I pieces that are from 2 to 6 inches 1 in diameter are said to be the pro- I duce of large trees. Snow, in navigation, the largest, of I European two-masted vessels. The I sails and rigging are exactly similar I to those of a ship, only behind the I mainmast of a snow there is a small spar or mast, fixed into a j block of wood on the quarter-deck, || which carries a sail resembling the 9 mizen of a ship. Snying, in navigation, a circular plank I edgewise, to work in the bow. Socle, in architecture, a flat square ?! member under the bases of the J pedestal of statues and vases. Soffit, in architecture, any timber ^ ceiling formed of cross-beams or flying cornices, the square com- |fl partments or panels of which are I enriched with sculpture, painting. I or gilding. Sol, in heraldry,denotes or, the golden I colour in the arms of sovereign j princes. Solar month, that space of time oc- J cupied by the sun in going througli I one sign or a twelfth part of the i zodiac. Solar System, in astronomy, the, order or supposed disposition of I tj the celestial bodies which move round the sun as the centre of I their motion. Solar year, that space of time in: i which the sun returns again to the same equinoctial or solstitial point, which is about 365 days, 5 hours, and 50 minutes. Soldering is the process of uniting the edges or surfaces of similar or dis¬ similar metals and alloys, by partial j fusion. In general, alloys or solders i of various and greater degrees of | fusibility than the metals to be 1 joined, are placed between them, f and the solder, w : hen fused, unites i < the three parts into a solid mass: less frequently the surfaces or edges are simply melted together with an additional portion of the same metal. 434 OL SOUND. SOU •ole, the seat or bottom of a mine, applied to horizontal veins or lodes. Solidity, in geometry, the quantity of space contained or occupied by a solid body; called also its solid con¬ tents, estimated by the number of solid or cubic inches, feet, yards, etc., which it contains. !olidx are all bodies that have the three dimensions; and among geo¬ metricians those that are termi¬ nated by regular planes are called regular solids, such as the tetra¬ hedron, hexahedron, octahedron, dodecahedron, and icosahedron. iondelets of iron , used for the win¬ dows of St. Stephen’s chapel, are fastenings and cross-mullions. hugh, an adit or level for carrying off water. >ound is produced by a sudden shock or impulse given to the air: these impulses, if quickly repeated, can¬ not be individually attended to by the ear, and hence they appear as one continued sound, of which the pitch or tone depends on the num¬ ber occurring in a given time ; and all continued sound is but a repe¬ tition of impulses. The motion of sound through the air is at the rate of about 1125 feet per second at the temperature of 62°. At the freezing tempera¬ ture, when the air is denser, it is only 1089f feet per second. The method of determining this velocity is to watch the time that elapses between the flash and the report of a gun fired at the distance of several miles from the observer. As light travels at the rate of nearly 200,000 miles per second, its passage occupies a portion of time too small to be measured in any terrestrial distance. It may, therefore, be supposed to be seen at the distance of several miles from the observer at the very in¬ stant of its production. If, there¬ fore, an observer at one station begin to count seconds on an accu¬ rate dial, the moment he sees the flash of a gur. at another station, . say ten miles off, the number of seconds and fractions of a second which elapse between seeing the flash and hearing the report will give a divisor for the number of feet between the two stations, and the quotient will represent the ve¬ locity of sound in feet per second. All sounds, whatever their in¬ tensity, whether the noise of a cannon or a whisper,—whatever their pitch, whether from the dia¬ pason organ-pipe or the chirping of a cricket,—and whatever their quality, whether the finest music or the most grating noise,—all travel with the same amount of speed. When sound from any source is propagated in air, waves are formed similar in character to those which may be so beautifully studied when the wind is blowing over a field of standing corn. Now, when it is said that sound travels at the rate of 1125 feet per se¬ cond, it is not meant that the particles of air move through that distance any more than the ears of corn travel from one end of the field to the other; it is only the form of the wave which thus tra¬ vels. So with the particles of air: their individual movement is confined within narrow limits; but the effect of this movement is pro¬ pagated from particle to particle with the rapidity of 1125 feet per second, which, although it would be thought very rapid for a motion or the transfer of a body (being about ten times faster than the most violent West India hurri¬ cane), is yet very slow for 'the communication or transfer of mo¬ tion ; for, if we pull or push one end of a solid rod, or the liquid filling a long tube, the other end appears to move at the same in¬ stant : and although this motion must occupy time (unless the body were perfectly incompressible), it is much more rapid in these cases than in air, which, on account of 435 SOU SOUND. SOU its great compressibility, is one of the slowest conveyers of sound. Every one must have observed that vibration can he diffused through a long mass of metal or wood, so as to be heard at a greater distance than through air ; hut in this case, if the sound be loud enough to be audible through the air also, it will be heard twice, first through the solid, and then through the air. Iron conveys sound about 17 times faster than air, wood from 17 to 11 times, and water 4^ times faster than air. When waves of sound meet any fixed surface tolerably smooth, they are reflected according to the law of equal angles of incidence and reflection. In this way echoes are produced. Between two parallel surfaces a loud sound is reflected backwards and forwards, and seve¬ ral echoes are audible. Six may be heard between Carlton Terrace and the Birdcage Walk, in St. James’s Park, London; fourteen between the steep banks of the Avon at Clifton, and as many under Maidenhead railway bridge. When the parallel surfaces are much nearer together (as the walls of a room), although a large num¬ ber of echoes are produced, they follow each other too rapidly to be distinguished; and as they reach the ear after equal intervals, they produce a musical note, however unmusical the original noise may have been. Hence all the pheno¬ mena of reverberation. The pitch of the note depends on the dis¬ tance between the two walls which cause it, and may be calculated therefrom. A noise may also produce a musical echo by being reflected from a large number of equidistant surfaces receding from the ear, so that the sound reflected from each may arrive successively at equal intervals. If we stamp near a long row of palisades, a shrill ringing will be heard. A fine in- 436 stance of the same kind is said to occur on the steps of the great Pyramid. If the distance from edge to edge of each step were 2 feet 1 inch, the note produced ! would he the tenor c, because i each echo (having to go and re- turn) would he 4 feet 2 inches i later than the previous one, which i is the length of the waves of that I note. But as the steps gradually ! diminish in size upwards, the echo, J if produced, and heard at the hot- ; tom, must gradually rise in pitch. I Sir Isaac Newton discovered a i wonderful coincidence which exists j between sound and colours, and proves mathematically that the spaces occupied by the colours in the prismatic spectrum correspond with the parts of a musical chord, i when it is so divided as to sound the notes of an octave. So this resemblance may now be consi- t dered as extending further, for as in music, so likewise in colours, it will be found that harmony con¬ sists in distance and contrast, not in similitude or approximation. Two notes near each other are grating to the ear, and called dis- j cords: in like manner, two colours very near each other are unpleas- i ing to the sight, and may be called i discordant. The science of acoustics is lit¬ tle understood, consequently not i studied in theory. The want of knowledge of the theory of sound (phonics), in architecture, is a po¬ sitive evil, and ofttimes of grievous complaint made of our public build¬ ings, after the expenditure of con¬ siderable sums of money. Sir John Herschel states, that sounds of all kinds agree in the following par¬ ticulars:—1. The excitement of a motion in the sounding body. 2. The communication of this motion to the air and other intermedium which is interposed between the : sounding body and our ears. 3. The ; propagation of such motion from i particle to particle of such inter- i SOU SOUTHWARK BRIDGE. SOU medium in due succession. 4. Its communication, from the particles of the intermedium adjacent to the ear, to the ear itself. 5. Its convey¬ ance in the ear, by a certain me¬ chanism, to the auditory nerves. 6. The excitement of sensation. The motion of sound has been de¬ monstrated by Chladin on plates of glass and metal, by strewing sand on their surfaces, and observ¬ ing the forms it assumed when the sound ceased, the sound being pro¬ duced on the plate by a violin bow. Sound has been used to discover the nature of disease: by the ste¬ thoscope, an instrument similar to a flute tube, physicians ascertain the state of pulmonary disorders, by applying it to the exterior sur¬ face of the body covering the lungs. In Chladin’s theory, it is stated that rooms will be favour¬ able to the transmission of sound when arranged to facilitate its na¬ tural progress,—when its intensity is augmented by resonance or si¬ multaneous reflection, so that the reaction is undistinguishable from the primitive sound,—when not too lofty or too vaulted,— when there is not a too extensive surface for the sound to strike against at once, —when the seats are successively elevated. He observes, that when the enclosed space does not exceed 65 feet, any form may be adopted for a room ; that elliptical, circular, and semicircular plans produce prolonged reverberation; parabolic plans and ceilings are the best for distinct hearing, and that for con- cert-rooms, square and polygonal plans should have pyramidal ceil¬ ings, and circular plans domed ones, and the orchestra be placed on high, in the centre, to produce the best effect, and avoid echo. Mr. Robert Mills, an American ar¬ chitect, describes the House of Re¬ presentatives of the United States Congress as the most elegant le¬ gislative hall in the world: the plan is a semicircle of 96 feet chord, 437 elongated in its diameter line by a parallelogram 72 feet long by 25 feet wide : the height to the enta¬ blature blocking is 35 feet, and to apex of the domed ceiling 57 feet, which is pierced by a circular aperture, crowned by a lantern. Besides additional seats and other improvements, a more important object has been accomplished,— namely, rendering the hall a better speaking and hearing room, in which it was before seriously de¬ ficient. The voice is now com¬ paratively distinct, and the ear not sensible, except in a few particular points, of any reverberation of the sound : where the voice before was confused and indistinctly heard, it is now full and clear. Sounding-board , a canopy over a pul¬ pit, intended to diffuse the sound of a preacher’s voice through the church. Southwark bridge, this bridge, design¬ ed by Mr. John Rennie in 1811, “ is admirably suited to the situation, as it will tend to remove the irre¬ gularity of shallows in this part of the river, by dividing the stream, and thereby directing the current into three regular channels, and consequently removing those sand¬ banks so injurious to‘navigation.” The bridge is an iron-work of three arches. The middle arch is 240 feet span; the other two, 210 feet each. The piers are 24 feet each; whole span of the river about 708 feet between the abutments. The abutments are built of stone with dowels introduced into every course of masonry to connect them firmly together, to prevent the possibi¬ lity of their sliding, and to ena¬ ble them effectually to resist the laterial thrusts. The foundation for the masonry is formed by grat¬ ings of strong timber resting upon numerous piles, driven in a slant¬ ing direction, forming an angle with base of the abutment. The foundations of the piers are from 9 to 10 feet below 7 the bed of the SPA SPECIFIC GRAVITY, river, on a strong flooring of tim¬ ber resting on numerous piles, driven perpendicularly; the courses of masonry are dowelled and laid horizontally. The depth of the foundations were laid thus deep to provide against the deepening of the river should London bridge he rebuilt or altered. The width of the roadway and footways between the parapets is the same as on Blaekfriars bridge, 42 feet. Spalling , in mining, breaking up into i small pieces for the sake of easily ; separating the ore from the rock, [ after which it undergoes the pro¬ cess of lobbing. | Span, or chord of an arch, an ima¬ ginary line extending between its | springing on each side. ! Spandril, an irregular triangular space formed between the outer curve or extrados of an arch ; a horizontal line from its apex and a perpendi¬ cular line from its springing; also a space on a wall between the outer mouldings of the two arches, and a horizontal line or string-course above them; likewise between similar mouldings and the line of another arch rising above and en¬ closing the two. Spandril bracketing, a cradling of brackets fixed between one or more curves, each in a vertical plane, and in the circumference of a circle whose plane is horizontal. Spanish and Moorish Architecture. “ St. Ferdinand III. of Spain con¬ quered many places from the Moors, and among others that of Alhamra, the inhabitants of which retreated to Granada, and settled in a quarter of that city, which took the name of their ancient country. This was about 1226. From hence it appears that the name Alhambra, which Swinburne derives from the red colour of the buildings (the Red House), in fact was derived from their country or city; but where this country or city was I have not discovered, un¬ less it be Alhamra in the kingdom SEE of Granada, about 60 miles from : the south-west of the city. It was in the reign of Mahomet II. that the famous palace of Alhambra was begun. Mahomet began his reign j in 1273 and died in 1302/’ Spanish Black is a soft black, pre¬ pared by burning cork in the man¬ ner of Frankfort and ivory blacks ; and it differs not essentially from I the former, except in being of a lighter and softer texture. It is subject to the variation of the I charred blacks, and eligible for the I same uses. Spanish Red is an ochre differing lit- I tie from Venetian red. Spans hade,a large bolt driven through I the forecastle and forelocked un- i der the forecastle-beam, and under and upon the upper deck-beam ; on the forecastle it has a large square ring, for the end of the davit to fix in. Spar, a piece of timber employed as a eommon rafter in a roof. Specific Gravity of a body is the relation of its weight, compared with the weight of some other body of the same magnitude. A body immersed in a fluid will sink if its specific gravity be greater than i that of the fluid ; but if it be less, the body will rise to the top, and will be only partly uncovered. If the specific gravity of the body and fluid are equal, then the body will remain at rest in any part of the fluid. If the body be heavier than the fluid, it loses as much of its weight when immersed as is equal in weight to a quantity of the fluid of the same bulk. If the specific gravity of the fluid be greater than that of the body, then the quantity of the fluid displaced by the part immersed is equal in weight to the weight of the whole body. Therefore the specific gra¬ vity of the fluid is to that of the body as the whole magnitude of the body is to the part immersed. The specific gravities of equal so¬ lids are as their parts immersed in 438 SPIRA. SPE the same fluid. The specific gra¬ vities of fluids are as the weights lost by the same immersed body. To form a Table of the specific weights of various substances, it is necessary to select one as the stan¬ dard of comparison: in practice, pure water is always chosen as the starting point for solids and liquids, and pure atmospheric air for gases, the number 1 (1-000) expressing their specific gravities. The forma¬ tion of two series is considered to be more convenient than the com¬ parison to all bodies by one stand- • ard, on account of the perplexity of the numbers which would result. Solids and Liquids. Water . 1-000 Platinum . 21-3 Gold . 19-5 Mercury . 13-5 Lead . 11-45 Silver. . . 10-5 Copper . . 8-96 Iron, cast . 7-2 Iron, rod . 77 Steel . 7-8 Diamond . 3-5 Rock Crystal . . 2-6 Window-glass . . 2-52 Wax ... . 0-964 Sulphuric acid . 1-84 Oil of Turpentine . . 0-865 Spirit of Wine (strong) . 0-83 Ether . 0-72 Cases. Atmospheric air . 1-000 Oxygen . , . 1-106 Hydrogen . 0 069 Nitrogen . 0-972 Carbonic acid . . 1-524 Carbonic oxide . 0-967 Pit gas . . 0-558 Light gas . 0-985 (For the specific gravities ofsome other substances, see Data, etc.) Spend, in mining, to break ground, to work a way. Spere, the screen aeross the lower end of the hall, in domestic build¬ ings of the middle ages. 439 SPI Sperver, the wooden frame at the top of a bed or canopy. Sphere, in geometry, a globe, a solid contained under one uniform sur¬ face, every point of which is equally distant from a point within, called j the centre of the sphere, and may j be conceived to be generated by the revolution of a semicircle about its diameter, which is fixed, and is called the axis of the sphere. Spherical bracketing, the forming of brackets to support lath-and-plas- ter work, so that the surface of the plaster shall form the surface of a sphere. Spheroid, a solid body resembling a ! sphere, supposed to be generated by the revolution of any oval about an axis. Spheroidal bracketing, the bracketing prepared for a plaster ceiling whose surface is to form that of a spheroid. Spice-plate. At the conclusion of Queen Anne Boleyn’s coronation dinner, she took wafers and ipocras. “ The table was then taken up, and the Earl of Rutland brought up the surnap, and laid it at the boord’s end, and the Queen washed; she arose and stoode in the middest of the palace hall: to whom the Earl of Sussex, in a goodlie spice-plate, brought a void of spice and com¬ fits.'” Spiceries and pepper-boxes were made very large in the Tudor times, and placed on the high table: their shape was that of a totver, castel¬ lated and triple-turreted, into which all kinds of spices were placed, of which our ancestors were inordinately fond. Spinning-jenny, in mechanics, a ma¬ chine used in the cotton manufac¬ tories to turn a great number of spindles, by means of bands from a horizontal wheel. Spinning-wheel, the wheel formerly employed in the spinning of mate¬ rial for textile fabrics : it consisted of a wheel which gave motion to a spindle, on which the thread spun by the fingers was wound. SPRINGS. SPI Spira (Latin), the base of a column : this member did not exist in the Doric order of architecture, but was always present in the Ionic and Corinthian; and besides the bases properly belonging to those orders, there was one called the Attic, which may be regarded as a variety of the Ionic. Spiral, in geometry, a curve-line of the circular kind, which in its pro¬ gress always recedes more and more from its centre. In architecture, a curve that ascends windingabout a cone or spire, so that all its points continually approach its axis. Spire, in geometry, a line drawn pro¬ gressively round the same axis, with a distance between each cir¬ cle ; a curve-line; anything contor¬ ted or wreathed ; a curl, a twist, a wreath. In architecture, it de¬ notes anything growing up taper; a round pyramid, a steeple. Spirit of wine, or alcohol, is weaker than essential oils, and is so vola¬ tile as to be of use only as a me¬ dium for combining oils with resins, etc., as a powerful solvent in the formation of spirit-varnishes, and in some degree as an innocent pro¬ moter of drying in oils and colours. In picture-cleaning it affords also powerful means of removing var¬ nishes, etc. Spirit-level, a cylindrical glass tube, filled with spirit of wine, except a small bubble of air. In whatever position the tube may be placed, the bubble of air will always tend to the highest part of it; but when placed in a perfectly horizontal po¬ sition, the bubble will remain sta¬ tionary at the centre of the tube. Spir/ceting, the strake wrought on the ends of the beams of a ship ; where there are ports, it is the two strakes worked up to the port-cells; in whicli case the middle of the planks should not be reduced, unless it occasions the butts to be less than 6 inches. Spit.al, a hospital. Splashers, screws or guards placed SPR over locomotive-engine wheels (u- sually faced with brass), to prevent ; any person on the engine coming i in contact with the wheels, and 1 also to protect the machinery from | any wet or dirt thrown up by the wheels. Splay, the slanting or bevelled expan¬ sion groin, in Gothic and Domes- [ tic architecture, to doors, windows, and openings in walls, etc. Split-pins and cotters, round and flat j pins, with a head at one end, and i split at the other end. They are | ' used through the ends of bolts, [ to keep them from getting out of j their place, the split end being | opened like the letter «j, to keep the pin or cotter from falling out. Spoons. In eating, spoons seem to j have been almost the only aid to the fingers at a very early period of j our history. “ Knives (ancient as they are) were first made in Eng- [ land in 1563, by Thomas Mathews, | on Fleet Bridge, London,” and were therefore only obtainable, in any considerable number, before that time, by the upper classes of society. Horn and wood were the materials of which spoons were made down to Elizabeth’s reign, when pewter became common, and was much improved. Spray, in navigation, the sprinkling of the sea driven from the top of a high wave in stormy weather. Spring, in mechanics, an elastic body, which, when distorted or com¬ pressed, has the power of restoring itself; any active power by which motion is produced or propagated. Spring, in navigation, a rope passed out at one extremity of a ship, and attached to a cable from the other, to bring her broadside to bear upon an object. Springs, in locomotive engines, the elastic steel supporters of the boiler and frame upon the axles, named after the particular parts to which they apply ; as leading-springs for the leading-axle, driving-springs for the driving-axle,trailing-springs 440 SPR SPRINGS. SER for the trailing-axle,tender-springs, drag-springs, buffer-springs, piston- springs, vaive-springs, etc., all pro¬ portioned to the particular duty they have to perform. Sprbigs. Water-springs, top-springs, springs of the deep, etc. In con¬ templating the origin and utility of water-springs,as dispersed upon the face of the earth, for the use of man and beast, and as far deep in the earth as the miner’s art has led,-— we find much both to inform and amuse those who have not made this subject their study. All springs take their source from the seas, lakes, and rivers : by the heat from that great luminary of our earth, the sun, they are evaporated into the upper regions, and there rare¬ fied, forming clouds filled with rain, which, by attraction and different causes, is plentifully showered upon the earth. It has been urged by some, that it is impossible for rain to supply the copious springs that arise in stony countries, where there is little appearance of a re¬ ceiving soil, and that rocky ground is impervious to them. But it must be admitted, that if rocks make a discharge of water, they are also capable of receiving it; and that rocky countries are generally as well supplied with springs as others, is well known to all travel¬ lers. One of the most stony coun¬ tries in Europe is Norway, where there is an abundant supply of pure water. It has also been stated that those places where it never rains, both in Africa and some parts of America, are yet well supplied with springs, and at times have flooded rivers. Whence come their springs ? The Nile, Niger, etc., are rivers of magnitude, and drain the greatest part of Africa. They are seldom replenished with rain; but they receive their immense floods from the extensive mountainous country lying above and behind them, where they have all kinds of weather; and some of the hills are 441 annually covered with snow, as well as those districts in America where it seldom rains: but the dews are very prolific, so much so that on walking out in the evening or early in the morning, amongst the herbage, it is nearly the same as in this country after a shower of rain. Hence it may be fairly pre¬ sumed, that the springs of those countries are fed by the excessive dews, similar to rain in other parts of the world, drawn from seas, lakes, and rivers, from the exhala¬ tions by the sun during the heat of the day. In those tropical cli¬ mates, night and day are nearly equally divided. Nature is thus perfect in all her works, by allow¬ ing a sufficient period for the de¬ scent of dews to supply the place of rain. It has been also asserted, that the principal springs come from the sea, and ascend their different chasms in the lower parts of the earth connected with it; that the water is then forced in, divested of its saltness, and made fresh by per¬ colation through the sand or silt in those chasms. It then becomes, the lighter fluid. The superior gravity of the salt then causes it to rise to the height of the highest hills. This hypothesis has proved to be unsound. The water of salt springs, from which so large a por¬ tion of salt is made, by evaporation, pumped up from the coal-pits at Butley, in Durham, and at Newcas¬ tle, is not sea-water, but is of a redder colour, and contains a far larger portion of natron. But what is still a greater proof that those salt-springs have no connec¬ tion with the sea, is, that in the middle of the river Wear, between Durham and Bishop’s Auckland, during the droughty months of summer, when the waters are low, from a rock bottom arises one of the finest salt-water springs known, many degrees salter than that of the sea, surrounded by copious SPR STADIUM. STA streams of fresh-water; and this place is between 200 and 300 feet above the level of the sea. What siphon-like power could force it to this altitude, so far within the land, from that fancied source? All these kind of springs receive their salt¬ ness from passing through beds or mines of salt, such as those at the Wicke, in Cheshire, etc., or some matter yet unknown, of a less dense body, that will more easily communicate its salter particles to the water running through it. What say the inspired writers ?— “ There is a multitude of waters in the heavens and “ He causes the vapours to ascend from the ends of the earth:” “He makes the rain.” That is from its seas, its lakes, and rivers, by natural exhala¬ tions, the clouds are replenished. “ He bindeth up the waters in his thick clouds ; and the cloud is not rent under them.” “ Who hath divided a watercourse for the over¬ flowing of its waters, to cause it to rain on the earth ?” The vapours which arise from the sea are much more than sufficient to supply both the surface of the earth and the i rivers with water; whilst the mountains, by their particular struc¬ ture and formation, attract and, as it were, arrest the vapours and the rain that fluctuate about in the at¬ mosphere ; and having collected [ them in their reservoirs, dismiss I them again through their sides, either in perpetual or intermitting currents. Spring-balance, in locomotive engines, a spiral spring weighing-balance, with an index and pointer. This is attached to the end of the lever, by which the pressure upon the safety-valve is adjusted. Spring-hooks, in locomotive engines, the hooks fixing the driving-wheel spring to the frame. A screw on the end of the hook regulates the weight on the driving wheels. Spring-pins, in locomotive engines, iron rods fitted between the springs and the axle-boxes, to sustain and j regulate the pressure of the axles. I Springing, the bottom stone of an i arch which lies upon the impost. Sprit, in navigation, a small boom or j pole which crosses the sail of a vessel diagonally from the mast to | the hindermost comer of the sail, | to elevate and extend it. Spri/sail, in navigation, the sail that belongs to the bowsprit. Sprung, in navigation. When a top¬ mast is broken or cracked near the cap, it is said to be sprung. Spurs, pieces of timber fixed on the hulgeways, and the upper end bolted to the ship’s side above water, for security to the bulge- ways. Square, in geometry, a quadrilateral figure with right angles and equal sides. In architecture, an area of four sides, with houses on each side. Square-rigged, in navigation, an epi¬ thet applied to a ship that has long yards at right angles with the length of the deck, in contradis¬ tinction to sails extended obliquely by stays or lateen yards. Square sails are such as are extended by a yard, distinguished from others I extended by booms, stays, lateens, and gaffs. Square tuck, when the planks of the bottom are not worked round to the wing transom, but end at the fashion-piece. Squaring the circle, in mathematics, is attempting to make a square that shall he equal to a given circle. Squinch, a term applied to small arches or projecting courses of stone form¬ ed across the angles of towers. Squint, an opening through the wall of a Roman Catholic church, in an oblique direction, for the purpose of enabling persons in the transept or aisle to see the elevation of the J Host at the high altar. Stadium, a Roman measure of length, jt nearly equivalent to our furlong. The term was also applied to a building, or an enclosed area, in which gymnastic and athletic ex- t 442 STAIRCASE. STA ercises, chariot-racing, and foot¬ racing, wrestling, and other public games, were exhibited. The sta¬ dium was divided into distances for the racers. Also a Greek structure, of an oblong area, terminated at one end by a straight line, at the other by a semicircle, having the breadth of the stadium for its base. Around this area were ranges of seats rising one above another, erected for the purpose of witness¬ ing the public sports at Olympia and other places Staircases. It was in the reign of Elizabeth that staircases first be¬ came features in English houses. Hand-rails and balustrades, unlike the rickety contrivances of modern days, were of gigantic proportions, and presented at once a bold, pic¬ turesque, and secure appearance; yet so variously and fancifully de¬ corated, that their effect was always pleasing and free from clumsiness. In the middle of Verulam House was a delicate staircase of wood, which was curiously carved; and on the posts of every interstice was | fixed some figure, as a grave divine with his book and spectacles, a mendicant friar, etc. In two of the principal chambers of Wressil i Castle are small beautiful staircases, with octagon screens, embattled at the top, and covered with very hold sculpture, containing double flights of stairs, winding round each other, after the design of Palladio. The east stairs at Wimbledon House lead from the marble parlour to the great gallery and the dining-room, and are richly adorned with wain¬ scot of oak round the outsides thereof, all well gilt with fillets and stars of gold. The steps of these stairs were in number 33, and 6 feet 6 inches long, adorned with 5-foot paces, all varnished black and white, and chequer-work; the highest of which foot-pace is a very large one, and benched with a wainscot bench, all garnished with gold. Staircases, in ordinary modern STA practice, should be light, spacious, and easy, seeming to invite people to ascend. Principal staircases should not he narrower than 4 feet, so that if two persons meet thereon, they may pass each other with con¬ venience; but they may be extended in breadth to 10 or 12 feet, accord¬ ing to the importance of the build¬ ing. The steps should never ex¬ ceed 6 inches in height, nor be less than 4 inches; but this latter height is only allowable in very wide stair¬ cases. The breadth, or the flat horizontal part, which is called the tread of the step, should not he less than a foot, nor exceed 15 inches. Stakes, in ship-building, are the regu¬ lar ranges of planks on the bottom and the sides of the ship, reaching from the stem to the stern. Stall, a place occupied by a monk, canon, dean, or prebendary, in the choir of a church; sometimes ap¬ plied also to the sedilia or pres¬ byteries for the officiating ministers in the wall of a chancel. Stamps, machinery for crushing ores. Stanchion, in ship-building, a small pillar of wood or iron, used to prop and support the decks, awning, etc. Stanchion, the upright iron bar be¬ tween the mullions of a window, screen, etc. Standards, timbers in the form of knees, with one arm on the deck, and the other fayed to a ship’s side. Stanlients, the upright pieces in a hulk-head, breast-work, etc., of a ship. Starboard, in navigation, the right- hand side of a ship, looking for¬ ward, as larboard is the left-hand. Starlings, in architecture, are large piles placed on the outside of the foundation of the piers of bridges, to break the force of the water and protect the stone-work. Statics, the science which considers the weight of bodies, or the motion of bodies arising from gravity. Stations, a generic term applied to fixed points or places, of which a series is included in any extended 443 STA STATIONS. works or arrangements. Thus we have Post-ottice Stations, Telegraph Stations,PoliceStations,Fir e-engine Stations, and Railway Stations. As applied to railways, the term station is a very comprehensive one, comprising a multitude of buildings and apparatus of an extended and costly character. Terminal stations of long lines of railway usually cover several acres of ground, and include buildings for the assem¬ bling of the passengers, and for classifying them in separate com¬ partments, according to the class of carriage they intend to occupy ; extended platforms, conveniently arranged for the arrival and de¬ parture of the trains, and well protected from the weather, and lighted by night. The level of these platforms is arranged so that persons walk directly into the car¬ riages, without ascent or descent, and their length is sufficient to serve many carriages, or two or more entire trains at one and the same time. A separate department of the station is usually allotted to the receipt, arrangement, and dis¬ tribution of parcels and goods of all kinds, from bulky bales and ponderous hogsheads down to a packet of such insignificant dimen¬ sions that it may hold no more than a half-ounce letter. The goods warehouses belonging to this de¬ partment are of great size, and fully furnished with cranes and moving and weighing gear of all requisite powers and dimensions, fitted to load and unload the goods-wag- gons belonging to the line, and all ordinary road vehicles. Besides these purposes, the terminal and first-class stations often include a complete engineering establishment of a practical character, in which the locomotive engines, carriages, trucks, waggons, etc., are repaired and built, and including foundry, smithies, pattern-turning, fitting, erecting, and repairing shops; the latter being provided with rails — I STA | _ below for running the engines into ] the building, and travelling cranes j above for lifting them entire when ] needed, or aiding in their dissection I with all the rapidity and delicacy of movement which commonly belong ! only to operations upon far smaller and easier handled subjects. The station also embraces ample build¬ ings or engine-houses, in which the locomotive engines are ranged like | so many post-horses in a road-side j stable, ready for immediate action, i and in which the raking out of fires | and the cleaning and adjustment I are daily performed. Complete ar¬ rangements are also included for i delivering water and coke to the tenders, and in some the necessary buildings and apparatus are com¬ prised for pumping the water from deep wells, for burning the coke, and even for manufacturing the gas to be employed in the lighting of the whole of the buildings and < shops. Board-rooms, clerks’-rooms j and offices, and residences for the station-master and assistants, be¬ sides store-rooms of all kinds, re¬ freshment-saloons, urinals, water- closets, police - rooms, telegraph- rooms, lost-luggage office, etc., etc., are also among the necessary de¬ tails of a principal railway station. The area of the station is covered with lines of railway for the pas¬ sage of the engines and carriages, and provided with turn-tables, re¬ volving and traversing, for readily transferring the carriages from onei line to another, besides switches and apparatus for connecting the several lines at intervals. Of the extent of some of these works at one of the metropolitan stations,: that of Camden Town, on the line of the North-western Railway, the J following particulai-s will convey some idea:—This station, which is chiefly for goods only, covers an area of 30 acres, and has a length of double line of 2500 feet for thej goods waggons only, and entirely! clear of the main line. The length! STEAM ENGINE. STA of single line of railway, exclusive of the main line, exceeds 12 miles. There are 112 sets of points for turning carriages from one line to another, 196 turn-plates, and 110 cranes, varying in power from 1J to 20 tons. The area covered with goods’ sheds exceeds 135,000 su¬ perficial feet, and that of the plat¬ form is 30,000 feet. The circular engine-house is 160 feet in diame¬ ter, and will contain 24 engines and tenders; the central turn-table within it is 41 feet in diameter. The annual consumption of gas exceeds six millions of cubic feet. In minor or intermediate sta¬ tions, the works are, of course, of smaller magnitude, and are not required to subserve all the com¬ bined purposes of a principal sta¬ tion. Statuary, a carver of images or re¬ presentations of life; one who practises or professes the art of sculpture. Staves, in joinery, the boards that are joined together laterally, in order to form a hollow cylinder, cvlin- droid, cone, or conoid, or any frus¬ tum of these bodies. The shafts of columns, in joinery, are fre¬ quently glued up in staves. Stay, in navigation, a strong rope employed to support the mast in the fore-part: to stay a ship, to manage the sails so that she shall not make any way forward, preparatory to I her tacking about. Staysail, in navigation, a sort of tri¬ angular sail extended on a stay. I Stays, outside, in locomotive engines, sling-stays binding the boiler and frame together. Stays, inside boiler, in locomotive steam-engines, rods of iron binding I together the flat ends of the boilers. The flat side of the dome is like¬ wise strongly bound together by iron rods. Without these stays, they could not resist the pressure of the steam against so large a surface. Stays, inside frame, in locomotive 445 STE engines, strong stays placed below the boiler, firmly fixed at one end | to the fire-box, and at the other end to the smoke-box: they sup- | port the inside bearings of the driving axle and other parts of the machinery. Stay-wedges, in locomotive engines, wedges fitted to the inside bearings of the driving axles, to keep them in their proper position in the stays. Steam, the vapour of hot water at the boiling point of 212 degrees. Steam-chest, in locomotive engines, a box attached to the cylinders, into which the steam is admitted by the regulator: the slide-valve works in this box over the steam- ports, which open into it from the cylinder. Steam-chest cocks, in locomotive en¬ gines, oil-cups, placed conveniently for lubricating the faces, of the steam-ports and slide-valve> Steam compression. The steam which has performed its duty in the cy¬ linder, but which has not escaped before the slide-valve closes the exhaust-port, is compressed by the advancing piston. This compres¬ sion begins, according to the lap and travel of the slide, from 2 to 3 inches from the end of the stroke, I and is of considerable amount. It is, however, of advantage in check¬ ing the momentum of the piston, and relieving the strain on the con¬ necting and piston rods at the end of each stroke, and is not therefore all lost power. Steam Engine, a machine for deriving power from the expansion which results from the conversion of water into vapour or steam by the appli¬ cation of heat. This expansion is so great that a given quantity of water becomes, when changed into the form of steam, enlarged to about 1,728 times its original bulk; and this expansion takes place with a force that may be termed irresis¬ tible. Thus if water be enclosed in a vessel, say of iron or any other strong material, and the water be STE STEAM expanded into steam, and insuffi¬ cient space left for the expansion, the vessel will be burst by the force of the steam within. A steam en¬ gine consists essentially of a vessel into which the steam is admitted, and which is provided with a mov¬ able disc, closely fitting the interior and capable of sliding within the vessel. This vessel is made cylin¬ drical, because this form gives the greatest strength and is the most readily fitted with the movable disc. The vessel is termed the cylinder, and the disc the piston. Supposing the cylinder to be placed upright, and fitted with a close co¬ ver, and that while the piston is near the bottom of it steam is ad¬ mitted to rush in through a pipe below the piston, the piston will be driven up by the steam, and if, when it reaches the upper part of the cylinder, the steam from below is shut off, and admitted through an upper pipe to press upon the top surface of the piston, it will be forced down again. Thus a rectili¬ near motion up and down is pro¬ duced, and this constitutes what is called the principle of the steam engine. All its other parts are for the purpose of regulating the ad¬ mission of the steam, and convert¬ ing the rectilinear motion produced at the cylinder into a rotary motion at the point where the power is required to be applied for working machinery. The steam, when no longer required for that purpose, is allowed to escape into the open at¬ mosphere, or conducted in a pipe to another vessel, which, being cooled by the application of cold water, rapidly condenses the steam, that is, reconverts it into water. If per¬ mitted to escape iuto the air, the steam has to force itself against the pressure of the atmosphere, whereas if conducted into a condenser, this force is not required. Hence steam of less pressure will work what is termed a low-pressure or condensing engine, while that already described STE j is for distinction called a high-pres- I sure engine. A third variety of steam engine is worked by shutting | off the steam before it has driven I the piston the whole length of the I cylinder, or completed the stroke, | as it is termed, and the subsequent I expansion of the steam completes I the impulse upon the piston. En- j gines thus worked are distinguished I as expansive engines. The princi- pal difference in the mechanism of ) condensing and expansive steam I engines is in the movement of the I apparatus which admits and shuts I off the steam, or the valves, which act as doors within the pipes. The several parts of a condensing engine and its appliances are as follows: | 1st, the boiler, in which the steam | is produced from water by the ac- , tion of fire in the furnace beneath ; j 2ndly, the steam-pipe, in which the I steam is conveyed to the engine: I 3rdly, the steam-chests, in which | the steam is received, and which I ! communicates with the two indue- 1 tion-pipes that lead into the upper | | and lower part of the cylinder; | 4thly, the cylinder fitted with the I piston, and having pipes called the I eduction-pipes, through which the ] steam passes away when its work I in the cylinder is completed, into 1 the condenser; 5thlv, the air-pump, j which abstracts the water formed by the condensed steam, sending ' it into the boiler, producing a par¬ tial vacuum within the condenser, and thus assisting the escape of the steam from the cylinder; 6thlv, the condenser itself, which is kept cool with water pumped up by the 1 cold-water pump. The piston has a rod fixed to it, which works through a steam-tight opening or stuffing- box in the lid of the cylinder, and this piston-rod is attached to one end of a beam, which turns upon a centre, and the other end of which works a connecting-rod attached to a crank, to the side of which a ro¬ tary motion is thus imparted. In ii some engines the piston-rod is con- ENG1NE. 446 STE STEAM NAVIGATION. STE necteri by links directly with the crank, and these are hence termed direct-action steam engines, while the former are distinguished as beam-engines. In others, again, the piston-rod is attached to the crank without links, and the cylinder, instead of being fixed, is made to vibrate or oscillate: these are there¬ fore termed vibrating or oscillating engines. Marine engines for pro¬ pelling vessels on the water, and locomotive engines for propelling trains of carriages upon railways, are each distinguished by pecu¬ liarities of construction and ar¬ rangements, fitting them for their especial duties. Steam exhaust-port, in the locomo¬ tive engine, the passage opened be¬ low the slide-valve from the cylin¬ der to the atmosphere. It is placed between the two steam- ports, and is nearly twice their area, the more freely to permit the escape of the steam. It is open to the hlast-pipe, and is cut off from any communication with the steam in the steam-chest by the slide-valves. The arch part of the slide-valve opens the passage from the cylinder into the central ex¬ haust-port, where, through the blast-pipe and chimney, it escapes to the atmosphere, and by this means produces the draught on the fire. Steam-gauge, a contrivance to show the exact amount of pressure -of the steam ; it consists of a siphon- tube with equal legs, half-filled with mercury : one end is cemen¬ ted into a pipe which enters that part of the boiler which contains the steam; the other end is open to the atmosphere. A stop-cock is usually provided between this gauge and the boiler, so that it may be put in communication with the boiler at pleasure. When the stop-cock is open, the steam acting on the mercury in one leg of the gauge presses it down, and the mercury in the other leg rises. The difference between the two columns is the height of mercury which cor¬ responds to the excess of the pres¬ sure of the steam in the boiler above the pressure of the atmo¬ sphere ; or, in other words, to the effective pressure on the safety- valve. If half a pound per inch be allowed for the length of this column, the effective pressure of the steam, in pounds per square inch, is obtained. Steam Navigation. This is accom¬ plished by the application of steam power to the marine engine, by which vessels of all dimensions are propelled on the waters of the ocean or on the principal rivers. Whether by means of the paddle- wheel, or by the spiral or helix screw, the fluid is displaced and the vessel sent forward at the vari¬ ous speeds consequent upon the skill employed in the making of vessel and engine. Much compe¬ tition and many controversies have existed upon the best methods to be adopted. Many instances of failures have occurred from the simple circumstance of the builder of the ship and the constructor of the engine not acting in concert. Steam vessels for river passenger- traffic, when in trim and all their parts well constructed, average a speed of 15 miles an hour; in Ame¬ rica 18 miles; and sea-going ves¬ sels average on their way 12 miles. Cunard’s packet from Liverpool to Halifax and Boston have done more. The West India and the Peninsular and OrientalCompanies have splen¬ did vessels, which do credit to the companies for their enterprise,—to the builders for the construction of the craft, and to the engineers for the construction of the engines. Other companies exist who deserve their proportion of praise. It is to England and Scotland that the world is indebted for this new ele¬ ment of civilization. Steam-pipes, in locomotive engines, the pipes which collect and con- u 2 447 STE STEAM-W'HISTLE. STE vey the steam to the steam-chest: they commence inside the boiler. In boilers with domes, the receiv¬ ing pipe is raised as high as possi¬ ble, and turned back round the edges of the open end, to prevent any water which might rise so high from overlying the pipe. In boilers having no domes, the steam is col¬ lected in a horizontal pipe pierced with numerous small holes. After being collected, the steam-pipes are continued outside the boiler to the steam-chest. The internal dia¬ meter of the steam-pipe is usually rather more than one-fifth of the diameter of the steam cylinders: the area of the passages through valves, in some of Watt’s beam-en¬ gines, is nearly one square inch per horse power. This is in some cases too large for steam-passages, but rather too small for the exhausting valve-passages. Steam-pipe for tender, in locomotives, a small pipe attached to the boiler by a cock, for admitting the spare steam to heat the water in the ten¬ der. Steam-ports , in locomotive engines, two passages from the steam-chest to the cylinder. The steam is ad¬ mitted to and from these passages by the slide-valve opening the port for the admission of steam to the cylinder, and then by shutting off this port from the steam in the steam-chest, and, opening the same passage by which it entered, it is conveyed to the atmosphere. Steam-whistle, an apparatus attached to the boiler of a locomotive engine for the purpose of giving warning of its approach when running. The construction of the whistle is shown to one-quarter size in the annexed engravings. It is made of brass, and the foot, a, is cast hollow with a flange, b, at the bottom to bolt it on the fire-box: it has a cock, c, placed in it, with the handle d, and screw e, to keep it tight; the han¬ dle projects out, to allow firm hold to be taken of it. The cup f is fixed upon the foot a, by screwing the piece g upon it, and both are turned truly at their outer edges, leaving a very narrow passage, i i, four inches diameter,between them all round. The piece g is hollow, having holes, h, in its sides ; and a 443 _ STE STEEL. STE pillar, k, stands upon its centre, on which is screwed the bell, l l, the thin edge of which is brought just over the opening i, and half an inch above it. When the cock is opened, the steam enters the cup f through the holes h, and rushes out at the nar¬ row slit i, striking the thin edge of the bell, l, in a manner similar to the action in organ-pipes, and producing an exceedingly shrill and piercing sound. Some holes, m, are made in the top of the bell, to allow the steam to pass through, which improves the sound consi¬ derably. The size of the concentric part where the steam escapes, and the depth of the bell part, and their distance asunder, regulate the tones of the whistle, from a shrill treble to a deep bass. The cock should be steadily opened, to adjust the quantity of steam, so as to pro¬ duce the clearest sound. The steam whistle is very effective, and its sound can be heard at a great dis¬ tance. Steel is composed chiefly of iron and carbon; yet these alone will pro¬ duce but a poor and brittle article. Good steel contains a variety of elements, almost all of those, in fact, which are considered impuri¬ ties of iron when present in ex¬ cess. Steel is divided into four distinct classes,—Damascus steel; German steel; Blistered, or blister steel, to which class shear steel belongs; and Cast steel. The first is made directly from the ore, or hv weld¬ ing steel rods and iron rods toge¬ ther ; the second from pig metal, by depriving the latter of a portion of its carbon and impurities; the third from bar iron, by impregnat¬ ing it with carbon ; and the fourth class, or cast steel, may be made from either of the others, by melt¬ ing it in a crucible. Still, blistered steel appears to be the most ad¬ vantageous, so far as quality is con¬ cerned. Damascus Steel. This steel derives its name from Damascus, a city in Asia. The swords or scimitars of Damascus present upon their surface a watery appearance, and variegation of streaks of a silvery white, black, and grey colour, and fine and coarse lines, exhibiting regular and irre¬ gular figures. The excellent quality of these blades is proverbial: they unite hardness to great elasticity. Genuine Damascus steel is made directly from iron ore ; and meagre as our knowledge is concerning the subsequent manipulations, such as forging and hardening.it is known that the steel is smelted, in a kind of Catalan forge, from red oxide of iron, a red clay ore found in transi¬ tion slate. It is generally believed that the great strength of this steel is to be attributed to a small quan¬ tity of aluminum which enters into its composition, and which is de¬ rived from the clay of the ore, - an opinion which has this fact in its favour, that no material imparts a greater degree of tenacity to iron than alumina. Great exertions have been made to imitate this steel, in which, of all nations, the French have been the most successful. They have succeeded in imitating not only irregular figures, but ara¬ besques and initials, in the most ' beautiful manner. Still, the French I is far less tenacious and hard than the genuine Damascus steel. The virtue of the latter, therefore, must be sought for in the ore from which it is made. German Steel. This steel is made in two different ways, either directly from the ore or by converting the ore into pig- metal, and then into steel. The steel manufactured by the first me¬ thod is generally crude and irregu¬ lar, and therefore this method is seldom practised. The Stuck oven, orWulf’s oven, 449 STE STEEL, GERMAN. SEW as well as the Catalan forge, is one of the furnaces employed in the manufacture of steel from ore. In making steel, the blast is directed more upon the fuel than upon the iron : the tuyere is level: the iron is impregnated with carbon. The reverse is the case in the manufac¬ ture of iron. In the blue-oven, a kind of pig metal is frequently made, which is almost pure steel; but it is coarse, and never, even after the best refining, makes a good article. All manipulations, the object of which is to make steel directly from the ore, are unpro¬ fitable. To this class belongs the manu¬ facture of wootz, or East Indian steel. This is certainly a good steel, and is partially imitated in America. Wootz is smelted di¬ rectly from the ore, which is the black magnetic oxide of iron, in furnaces five or six feet in height, of the form of some foundry cupolas. Previously to smelting, the ore is finely pounded and washed, to re¬ move impurities. The manufacture of steel from pig metal does not depend so much upon the manipulations in the forge as upon the quality of the metal. The ores generally employed are the crystallized carbonate, spathic ore, often mixed in a slight degree with hematite, and the rich red peroxides. Magnetic ores do not answer for such work, and are therefore but seldom used. The same may be said in relation to the hydrated oxides. Pig metal for steel manufacture is smelted with as little lime or other flux as possi¬ ble. The principal flux to be re¬ lied on is manganese; but this al¬ ways exists in the ore, and is never used as an artificial admixture, though it is possible that an artifi¬ cial flux might be made of it. Steel metal is in most cases white. It is smelted by rather more ore than that which will make grey iron; but not with so heavy a burden as I that which will make 'white iron containing carbon in small amount. Any ore which contains foreign matter in such large amount as to make the addition of lime as a flux necessary, does not make good steel metal. The only mode of working the furnace is, of course, by means of charcoal and the employment of the cold blast. The forge fires employed in con¬ verting the metal into steel do not differ materiallyfrom those in which iron is made. The hearth of the former is generally larger and deeper, and the blast is stronger than that of the latter. Very little iron is connected with it. The bottom is generally formed of sand¬ stone, and the sides of braise, or charcoal-dust mixed with clay. The practical manipulation at these forge-fires varies according to loca¬ lity, to the form of the furnace, and the qualifications of the workmen. The main principle involved may be generalized under the following proposition :—If it is intended to make steel instead of iron, the metal should be melted before and off from the tuyere; and it should be kept, when melted, always be¬ low the blast, and never brought above or into the blast. By due attention to locality, everything else may be easily regulated. A skilful workman will soon ascertain that a flat hearth, an iron lining, and a strongly dipped tuyere will not make steel, though it will make iron, and that a weak blast will tend to produce iron. The crude steel, the result of the first operation, is generally thrown when red-hot into cold water, then broken and sorted. The most sil¬ very part, of the finest grain, is the best. Fibrous or partially fibrous bars are reserved for iron: they make a superior quality of bar iron. Bluish-looking steel is also thrown aside, for it will become fibrous iron before its impurities can be removed. The crude steel, drawn 450 STEEL, BLISTERED. STE out into bars an inch or an inch and a quarter square, is placed in piles composed of six or eight pieces then welded, and drawn out into smaller bars. This process, called refining, is repeated three or four I times, and each time the number of bars in the pile is increased. The smaller the bars of steel, and the greater the number of them placed together, the more perfect will be the refined steel. The piles are heated in a large blacksmith’s fire, by stone coal, which must be sufficiently bituminous to form an arch over the fire. Coal - slack, mixed with loam, is frequently used for this purpose; but it increases the waste of steel. The hammer I ' used for drawing steel should be light, weighing no more than 150 pounds, and ought to make from 300 to 400 strokes per minute. Great skill and dexterity are re- I quired to draw steel bars. It is highly important to perform this operation well, as the quality of the steel is, in some measure, depend- ! ent upon the manner in which it has been hammered. In those countries where German steel is made, a remarkable article is manufactured, which deserves notice. It is harder than the best cast iron, but so brittle that it can¬ not bear any bending when cold. This article is cast steel: it is de¬ rived from the remelted steel me¬ tal. From 200 to 250 lbs. of this metal are generally melted. When that quantity is melted down in the bottom of the forge-hearth, a small portion of it is let off: it should be tapped as low at the bottom as possible. This mass, which flows like cast iron or cast I steel, is broken into small pieces, and pounded into a flat piece of wrought iron, which has a brim drawn up around it: this piece serves as a crucible. It is covered with loam, and exposed to a heat which will melt the cast iron, and unite it firmly with the wrought STE iron. The former then forms a thin coating of steel over the one side of the iron, of immense hardness. This does not become soft, even though a long time is consumed in tempering it. Wrought-iron plates, furnished with such a coating of steel, are used as draw-plates for wire. The holes for the wire are punched when it is warm; for, when cold, its hardness is so extreme, that no drill-bit can make any im¬ pression. Iron for Blistered Steel. England is not so celebrated for the production of iron suitable for the manufacture of steel as Sweden and Russia, upon which countries we must depend mostly for our knowledge of the mode of working it, and the kind of materials from which iron for the steel factories is made. The peculiarities of such iron are so remarkable, that, by means of the most accurate chemical ana¬ lysis, we cannot detect any differ¬ ence between a given kind which produces a superior, and another kind which produces an inferior steel. Were it possible to detect this difference, it would prove to exist in the cinders. The iron from which blistered steel is made is a soft, fibrous, often grained, wrought iron, of a peculiar silvery whiteness. It is made from mottled pig iron, smelted from magnetic ore by char¬ coal and cold blast. In making pig iron for the ma¬ nufacture of steel, the ore should be carefully roasted by wood, char¬ coal, or braise. The height of the blast-furnace must not exceed 35 feet, and the result is still more favourable when it does not exceed 30 feet. The boshes should mea¬ sure about 9 or 9£ feet. There ought to be either no hearth at all, as in the Swedish or Styrian fur¬ naces, or one that is very low. Blast of medium strength, and tu¬ yeres somewhat inclined into the 451 STE STEEL, BLISTERED. STE hearth, are requisite. Hot blast must be rejected altogether. In fact, the operation should he con¬ ducted in such a manner as to pro¬ duce mottled iron of great purity. In fluxing the ore, lime can he em¬ ployed, but only in such limited quantity as not to cause the furnace to smelt grey or white iron; for neither will be serviceable in the manufacture of good steel. In converting pig into bar iron, the German forge is generally em¬ ployed in Sweden, and for this pur¬ pose may he considered the most perfect. The refining process re¬ sembles the boiling of iron : this is required to make the texture of the iron as uniform as possible. White pig metal will not boil, and it works too fast. Grey pig metal contains a large amount of impurities, and the greatest attention at the forge will not remove them in sufficient amount to answer any practical purpose. In making blistered steel, it is essential to consider not only the quality, that is, the chemical com¬ position of the iron, but also its form. The bars are generally flat: good qualities are from an inch and a quarter to two inches in width, and half an inch thick. For ordi¬ nary steel and for cast steel, the thickness of the bars may be three- quarters of an inch; but in these cases, more time is not only re¬ quired in blistering, but the heart of the bar is still imperfectly car¬ bonized. Thin bars work faster, and make a more uniform steel than thick and heavy bars: the latter are always more or less raw inside, and contain too much car¬ bon outside. If the iron is very pure, it may be short, that is, with¬ out fibres: it may be hard, if it is at the same time strong. Impure iron will not make steel of good quality. As iron void of fibres is generally more impure than that containing fibres, the safest plan is to convert all the iron into fibrous iron. Coarse fibrous iron, what¬ ever may be its strength, does not make good steel: that with black spots or streaks of cinder must be I avoided by all means. The indica- | tions of a good iron are, a silvery- white colour, short fine fibres, a bright metallic lustre, and an ag¬ gregation so uniform, that black spots cannot be detected with a lens. The transformation of bar iron into steel requires no special skill or knowledge. The quality of the steel is determined by the quality of the iron from which it is manufactured. Blistered Steel. The furnace for the conversion i of wrought iron into blistered steel i is from 12 to 15 feet wide, and 20 or 25 feet deep. A conical chim- ) ney, 40 or 50 feet high, is designed to lead the smoke above the roof ij of the factory. The iron is placed in boxes composed of fire-brick or sandstone tiles: these boxes are from 24 to 36 inches square, and j from 10 feet to 16 feet in length. Square holes at one end of the furnace serve for the admission of ' the iron, and the entrance and exit of the workmen. Holes are also I made in the ends of the boxes, through which one or more of the bars may be passed, for the pur¬ pose of testing the degree of ce¬ mentation, and the progress of the work. The boxes are enclosed in the furnace, which is provided with a grate and fire-brick arch. The iron, w T hen placed in these boxes, is imbedded and carefully laid edge¬ wise in a cement composed of one part hard charcoal, one-tenth part of wood ashes, and one-twentieth part of common salt. The mixture is ground into a coarse powder un¬ der edge-wheels. If the boxes are 10 feet in length, the iron bars may be 9 feet 10 inches. The cement i is laid about 2 inches deep in the bottom of the box. The bars of 452 STE STEEL, BLISTERED. STE iron are then put in edgewise, se¬ parated by f of an inch space, which is filled with cement, and the top of the bars covered to the depth of ^ an inch. Upon this another layer of bars is set, but in such a manner that the second layer overlies the space which separates the bars of the first layer. In this way the box is filled to within 6 inches of its top. The remaining space is filled with old cement powder, on the top of which, finally, damp sand or fire-tiles are placed. The fire ought to proceed slowly, so that three or four days shall elapse before the furnace and the cement-boxes as¬ sume a cherry-red heat. In fact, the fire should be conducted in such a manner that the heat may be slightly increased every day during the whole course of the operation. A diminution of the beat, from the time of starting, oc¬ casions a loss both of fuel and time, and is injurious to the chests. A well-conducted heat will finish a small box in four or five days, and a couple of boxes, 3 feet square, in ten or twelve days. The furnace and boxes should be cooled very slowly; for a sudden change of temperature is very apt to break the fire-tiles, or sandstone slabs, of which the boxes are constructed. The trial-bar, which passes through the small hole in one of the ends of the box, and in a corresponding ( hole in the furnace wall, is some¬ what longer than the other bars, so as to be taken by a pair of tongs, and pulled out of the box. There are frequently several of such bars, i for a bar that is once pulled cannot be returned; and if, in a case in which there is but one trial-bar in ' the chest, the bar is pulled too soon, no further opportunity of testing the progress of cementation is afforded. The trial-bars are not sufficiently long to project over the j wall of the chest. The trial-hole is closed by a clay stopper. Six days I may be considered a sufficient time for blistering bars of common steel, such as spring steel, saw-blades, and common files; eight days for shear steel and steel for common cutlery; and ten or eleven days for the better qualities of steel, and common cast steel. Rods for the finer sorts of blistered, and the finest kinds of cast steel, are re¬ turned to the boxes after the first heat, and receive two or three blis tering heats, according to the qua¬ lity of steel wished to be obtained. From eight to twelve tons of iron may be charged in two chests, and from four to eight tons in case the furnace contains but one chest. Two small chests are preferable to one large chest. The smaller the chest, the more uniform will the steel become. The regulation of the fire in the furnance is a some¬ whatdelicate operation. Iron of dif¬ ferent qualities requires a different degree of heat; but the heat can be easily managed by recollecting that it should be steadily increased every day. If it is not sufficiently strong, the iron will absorb but very little carbon, and the work will proceed slowly. If the heat is too great, the rod iron will be converted into cast iron, or, at least, into some¬ thing similar to it; for, after being once overheated, it will not, even with the greatest labour and atten¬ tion, make good steel. If the heat is carried so far as to melt the blis¬ tered iron in the boxes, it is con¬ verted into white plate-metal,—the kind from which German steel is manufactured. But this melting cannot well take place, and if it should occur, the slow cooling of the chests, which is equivalent to tempering, will transform the white metal into grey cast iron. The latter is converted into steel with greater difficulty than the white metal. Blistered steel, taken from the chest, is very brittle: the excellence of its quality is in proportion to its brittleness. The presence of fibres v 3 453 STE STEEL, BLISTERED. STE indicates that the cementation is unfinished. A fine-grained, white aggregation, likeiron rendered cold¬ short by phosphorus, indicates that the cementation has not advanced beyond its first stages. A crystal¬ line form of the grains is an in¬ dication either of imperfect ce¬ mentation, or of too low a heat, or bad iron ; still, the best kind of iron will exhibit these crystals, and they can be observed by the lens, if the temperature of the chests has not been kept sufficiently high. If a good article be desired, a repe¬ tition of the operation is, in such cases, necessary. The grains of good steel appear like round glo¬ bules, when taken from the chest and broken. After an imperfect cementation, the colour of the steel iswhite. Good blisteredsteelshould be of a greyish colour, and of a bright lustre; and it should exhibit a coarse grain, as though it were an aggregation of mica or leaves of plumbago. That which exhibits a fine grain, of crystalline form, and which is of a white colour, is always a poor article. But one degree of heat is favourable for each kind of iron: if that degree be hit upon, the operation goes on well; if otherwise, a favourable result can¬ not be expected. The composition of the cement and the construction of the boxes and furnace have little influence on the quality of the steel. Where the iron is of the best qua¬ lity, and where the degree of heat is most favourable, the fracture of a bar taken from the chest will ex¬ hibit the largest grains or leaves. An indication of good iron is its increase of weight in cementation ; while bad iron neither gains nor loses in weight, iron of good qua¬ lity will gain at the rate of from 15 to 20 per cent. This applies especially to strong and pure iron. The surface of the rods, whatever number of bliste rs they may have when taken from the chest, must be clean. Bad iron makes but few blisters, or none at all: the surface of the rods is rough. With the ; quality of the iron the number and size of the blisters increase. Da- nemora iron draws blister close to i blister, and almost all of equal size. Common iron, that is, charcoal iron, raises but few blisters, and these are of irregular size. The best qualities of puddled*iron raise but few blisters. As might be expected, the tex¬ ture and quality of one bar, as well as the average which a chest con¬ tains, cannot be uniform. The in¬ terior of a bar, like the interior of the box, will be imperfect, while the external parts will be overdone. The steel should, therefore, be bro¬ ken, sorted, and refined. Pieces of uniform grain, as well as those including the extremes of quality, I are piled, welded, and drawn out into bars. This process must be repeated, if the grain is not suffi¬ ciently uniform for the desired pur¬ pose. Upon the skill of the ham¬ mer-man the quality of the steel, in a considerable degree, depends. Slow and heavy strokes and high heats depreciate its value, while its quality is improved by a low heat , and fast work. Rolling steel in a rolling-mill, or welding it in a re¬ heating furnace, makes it brittle, j and transforms it into a kind of cast iron. This result, however, can he partially remedied by again bringing the steel to the hammer. The influence of the tilt-hammer upon the iron is nowhere more ob¬ servable than in the manufacture of steel. It is impossible to make good steel independently of proper j hammer machinery. The tempera¬ ture at which the hammering should be performed is a matter of consi¬ derable importance: the steel will be spoiled equally by a too high • as by a too low heat. The secret of success appears to be the preven¬ tion of crystallization, which takes place at certain temperatures of the) j metal. Under favourable condi- j 454 STE STEEL, tions, definite compounds of car¬ bon and iron are formed; and these compounds crystallize: this crystallization causes brittleness. The greater the amount of foreign matter which is combined with the iron, the greater the brittleness. Blows of the hammer quickly re¬ peated, and the exposure of the metal a short time to a low heat, appear to be the means of prevent¬ ing crystallization,—at least, of di¬ minishing its extent. A sudden change of temperature augments the power of crystallization in the highest degree. This makes the iron hard, by giving rise to so strong an affinity between the iron and foreign matter, that the colour occasioned by the carbon disap¬ pears. The carbon is enclosed in the particles of iron, which is, in turn, crystallized by means of its strongly cohesive properties. White plate-metal of great purity, con¬ taining carbon in large amount, is harder than the hardest cast steel, but the strength of its cohesive properties, and the larger size of its crystals, are the causes of its brittleness. The best steel, if melt¬ ed at a high heat, similar to that of the blast-furnace, would appear in the same form as plate-metal, and would be quite as brittle. From the facts here stated, a conclusion may be drawn, that the impurities which increase the cohesive power of steel or iron may be retained, and the formation of crystals still be prevented. Cast Steel. The irregularity which is exhibi¬ ted in the texture of common steel gave rise to the invention of cast steel. Common steel is bro¬ ken into small pieces, and closely packed into a crucible made of good fire-clay. That which is in some degree more highly carbon¬ ized than usual is best adapted for cast steel; because, in the melting operation, it loses a por- 455 CAST. STE tion of its carbon. With the fire¬ clay, plumbago or coke-dust is mixed; but neither of these in¬ creases its durability, though dimi¬ nishing its liability to break on account of sudden changes of heat. This well-mixed mass is firmly pounded in an iron mould, with a movable cone for the interior. The crucible which is thus formed is air-dried and slightly burned before it is employed in the melt¬ ing of cast steel. For this pur¬ pose a crucible 5 inches wide at the top, and 16 or 18 inches in height, is generally employed. Every precaution must be taken to prevent it from cracking; for, in such a case, its contents are generally lost. The air-furnace for the fusion of the steel is similar in construction to those used by brass-founders: it is 2 feet deep and 12 inches square. The flue at the top is covered by a cast-iron trap-door. The top of the furnace coincides with the plane of the floor of the laboratory. Under the floor of the latter is an arch, into which the grates of the furnace may be emptied: this arch supplies the furnace with air, and in it the ashes accumulate. The cruci¬ ble is placed on a support com¬ posed of two thicknesses of fire¬ brick, and its top is covered with a lid. In many cases, pounded glass and blast-furnace cinders are laid on the top of the steel, as well to prevent the access of air as the oxidation of the carbon; but, if the lid fits well, this pre¬ caution is unnecessary: besides, these materials generally tend to glaze, and, as a consequence, to crack the crucible. In large fac¬ tories, ten or twenty furnaces may be put in one row, each furnace having its own chimney. In Eng¬ land the fuel employed is coke; but anthracite is far superior to coke for this purpose. The more compact the fuel, the better will STENCH-TRAP. STE STE be the result. In feeding the fur¬ nace with coal, great caution must be observed ; for a sudden charge of cold fuel is apt to crack the crucible. For this reason, square are preferable to round furnaces. The heat of the furnace must he conducted in such a manner that the melting shall commence from below, and not from the top. This is another reason why the form just described is preferable «to any other. All these advan¬ tages are increased by the employ¬ ment of blast, which, of course, is essential where anthracite is used. The time required to melt steel depends partly upon the draught of the furnace, partly upon the quality of the crude steel, and partly on the quality of the ar¬ ticle designed to he manufactured. From one to three hours is gene¬ rally required for a crucible con¬ taining 501bs. of metal. The stronger the steel, the greater the length of time consumed. The mass must become perfectly li¬ quid, no matter how long a time is required to produce this result. The liquid 6teel is then poured into previously heated cast-iron moulds, and cast in the shape of square or octagonal bars, 2 inches thick. Before casting, the steel in the crucible is stirred with a hot iron rod, after which a strong heat is applied for a few minutes. After casting, the top of the steel in the mould is covered with clay, to prevent its blistering, and to prevent the access of air. The cast rods are exposed to a cherry-red heat, and put, when almost black, to the hammer. The rapid succession of strokes heats the steel, and, if it is very hard, often in too high a degree. Each hammer requires a filter and two boys. In this case, as in that of blistered or German steel, ham¬ mering and heating need the ut¬ most attention. The quality of the steel depends upon the quick¬ ness with which the work is per¬ formed. The rods are heated in heating stones, constructed like sheet-iron ovens. Steeler, the foremost or aftermost plank in a strake, which is dropped short of the stern or sternpost of a vessel. Steelyard, in statics, a kind of balance having arms of unequal length, in which the weight is moved along the longer arm, and becomes in effect heavier in proportion as it is removed from the fulcrum or port. It was formerly named the Statera Romana, or Roman balance. Steeple, a spire or lantern ; the su¬ perstructure attached to the tower of a church. Steering-wheel, a wheel to which! the tiller-rope is attached, for the I convenience of steering a ship. Steeving, in navigation, denotes the I elevation which a ship's cathead or bowsprit is above the stem, or | the angle w hich either makes with | the horizon. Stem, the foremost piece of timber ' in a ship. Stem, in mining, a day’s work. Stemples, in mining, wooden pieces ; by which to go up and down the ; mine, instead of steps. Stemson, a piece wrought on the aft- part of the apron, continued as high as the middle deck or upper deck in small ships, the low er end j lapping on or scarfing into the i : keelson. Stench-trap, a contrivance for the prevention of the escape of effluvia from sinks and drains. These traps I are on the same principle as a gasometer: a cup inverted in water stops the escape of gas. (See the following plan and section of a trap in common use.) The cir¬ cular plan shows how the fluid is drained off through small holes. The arrows in the section show the course which the fluid takes in its way into the pipe leading into the drain. It will be evident, j from an inspection of the section, 456 that the inverted cup will be im¬ mersed in the fluid as high as the dotted lines. If, from neglect, the space intended for fluid only should Section of Stench-trap. be suffered to become filled with solid matter, the fluid will cease to run in the direction indicated by the arrows, and the utility of the traps will be destroyed : they should, therefore, be kept con¬ stantly clear from solid matter. Some persons,not understanding the principle on which the trap is constructed, remove the inverted cup when the water can no longer flow through it, and then leave it off. The consequence is, that, there being nothing to impede the gas from the drains from rising and flowing into the dwelling-houses, the houses very frequently become filled with noxious air. Step , in ship-building, a large piece of timber into which the heel of a mast is fixed. Steps for the masts are large pieces fitted across the keelson, into which the heel of the mast is fixed. The holes for the mast to step into should be cut in proportion to the steps, so as to leave sufficient wmod on each side of the hole to answer in strength to the tenon left at the heel of the mast; and if that should be rather too little the hole may be cut more thw’artships to answ'er the deficiency the fore and aft way. There are likewise large pieces called steps of the cupstands; and steps on the top-side, for the con¬ venience of getting on board. Stereobote, or Stylobate, a base ; the lower part or basement of a build¬ ing or column. Stereographic projection of the sphere; projection. Stereography, the art of representing solids on a plane. Stereometry, a science showing how to measure, or to find the solid contents. Stereotomy, art of cutting solids, or making sections thereof, as walls or other members in profile of archi- ture. Stereoscope (The) has the property of exaggerating the natural effects of perspective and relief. An optical delusion. The mind judges of the relative position, form, and magnitude of visible objects, by comparing their apparent outlines and varieties of light and shade, with previously acquired impressions of the sense of touch. The knowledge that such and such visual appearances and optical effects are produced by certain varieties of form, position, and distance having been already acquired, it substitutes with the quickness of thought the cause for the effect. The continual repeti¬ tion of such acts, which are ne¬ cessarily repeated as often as the sense of vision is exercised, and the extreme rapidity with which all such mental operations are per¬ formed, imagination of shape, dis¬ tance and position are subjects of visual perception. STE STERN-POST. STE Exceptional cases, however, are of a class of visual phenomena manifested independent of mere outline and varieties of light and shadow, and which no effort of art can transfer to convas. Inasmuch, also, as these phenomena are op¬ tional effects of distance, form, and position, they become, like the others, indications by which the mind judges of the relative forms and positions of the objects which produce them. Phenomena of this class are manifested, when the ob¬ jects viewed are placed so near the observer as to have sensible bino¬ cular parallax. The aspects under which they are seen in this case by the two eyes, right and left, are dif¬ ferent. Certain parts are visible to each eye which are invisible to the other, and the relative positions in which some parts are seen by one eye, differ from those in which the same parts are seen by the other eye. This difference of as¬ pect and apparent position, arises altogether from the different posi¬ tion of the two eyes in relation to the objects. It is a phenomenon, therefore, which can never be de¬ veloped, in the case of objects whose distance bears a large pro¬ portion to the distance between the eyes, because there is no sensible difference between the aspects un¬ der which such objects are viewed by the one eye and the other. The phenomenon, therefore, can only be manifested in relation to objects, whose distance from the observer is a small multiple of the distance between the eyes. It appears that the two eyes, right and left, will have different views of the bust; so that if the observer were to make an exact drawing of the bust with his left eye closed, and another exact draw¬ ing of it with his right eye closed, these drawings would not be iden¬ tical. One of them would show a part of the bust on the extreme right, which would not be exhibited in the other, and the latter would show a part on the extreme left, which would not be included in the former. Moreover, a part of the cheek and the eye would be shown in the drawing made with the right eye closed, which would not appear in the drawing made with the left eye closed. The stereoscopic pictures are ac¬ cordingly produced upon daguer¬ reotype plates, photographic paper, or glass. On daguerreotype plates they are necessarily opaque ; on glass they are transparent; and on paper may be either opaque or transparent, according to the thick¬ ness and quality of the paper. Since the greater number of ste¬ reoscopic pictures represent views of objects which must be so distant from the observer as to have no sensible binocular parallax, it may be asked how it is that stereosco¬ pic effects, so remarkable as those which are manifested by such pic¬ tures, can be produced. If the stereoscopic effects be the conse¬ quences of binocular parallax, and of that alone, how can such effects be produced by pictures of objects, which have no such parallax? When the pictures are produced on a small scale they are placed in the stereoscope, the eye-glasses of which will have the effect of caus¬ ing them to be viewed in lines con¬ verging at the same angle, as that formed by the optic axes of the two photographic instruments by which the pictures were produced. For a full and effective descrip¬ tion of this subject see Dr. Lard- ner’s serial work. Stern, the aft-part of a ship. Sterne-frame, the frame of timber that is composed of the stern-post, transoms, and fashion-pieces. Stem-post, the straight piece of tim¬ ber at the aftermost part of a ship, and to which both sides of the ship unite: the lower end is te¬ noned into the keel. It is gene¬ rally worked with'the butt-end up- 458 STONE. STE wards, being most suitable to the conversion of the timber; but in some ships which trade to a hot climate it has been preferred to work the butt-end downwards, be¬ cause in large ships it requires a piece of such growth whose juices towards the butt are nearly ex¬ hausted, and therefore it is sup¬ posed to last longer under water; whereas, by the heat of the wea¬ ther, when the butt is worked up¬ wards, it decays with dry-rot for want of moisture. Stem-sheets, in navigation, that part of a boat which is contained be¬ tween the stern and the hinder- most seat of the rowers. Stiff, in navigation, denotes the qua¬ lity by which a ship is enabled to carry a sufficient quantity of sail without danger of overset¬ ting. Still-house. Rules are given for build¬ ing these houses : the first caution is to lay the floor aslope, not flat, where any wet work is to be per¬ formed. It should be also well flagged with broad stones, so that no wet be detained in the crevices, but all may run off and be let out at the drains made at the bottom and sides. Stills for wines should be placed abreast on that side of the still-house to which the floor has its current. Fronting the stills, and adjoining to the back of the wall, should be a stage for holding the fermenting-backs; so that these being placed at a proper height, may empty themselves by means of a cock and a canal into the stills, which are thus charged with very little trouble. Hear this set of fermenting-backs should be placed a pump or two, that they may readily supply them with water by means of a trunk or canal leading to each back. Under the pave¬ ment, adjoining to the stills, should be a kind of cellar,whereon to lodge the receivers, each of which should be furnished with its pump to raise the low wines into the still for STO rectification ; and through this cel¬ lar the refuse wash or still-bottoms should be discharged, by means of a hole or other contrivances. Stilobatum, in architecture, denotes the body of the pedestal of any column. (See Stereobate.) Stone is found in various forms and conditions, embedded in and stra¬ tified under the earth’s surface. That portion of it which is used for building purposes, is a dense coherent brittle substance, some¬ times of a granulated, at others, of a laminated structure; these qua¬ lities varying according to its che¬ mical constitution and the mode in which it has been deposited. Some¬ times the laminated and granular rocks alternate with each other; at others, a rock of a mixed form prevails, partaking of the charac¬ teristics of both structures. Inde¬ pendent of these properties is its power of resistance to compression, which depends chiefly upon its che¬ mical combinations and the pres¬ sure to which it has been subjected whilst under the earth’s surface from the weight of superincumbent materials. The granite also, and other igneous rocks, owe their hardness to their having crystal¬ lized more or less rapidly from a fused mass. In attempting to ascertain the ultimate powers of resistance of rocks which have been deposited by the action of water, it is neces¬ sary to observe the direction in which the pressure is applied, whe¬ ther in the line of cleavage, or at right angles to it. In nearly all of the following experiments this pre¬ caution was attended to, and it will be seen that the strength is far greater when the force is exerted perpendicularly to the laminated surface, than when it is applied in the direction of the cleavage. In building with such stone, it is also important that it should be laid in the same position as that in which it is found in the quarry, as 459 STO the action of rain and frost rapidly splits off the laminae of the stone when it is placed otherwise. The strength of the igneous or crystal¬ line rocks is the same in every di¬ rection, owing to the arrangement of their particles. It might have been advantageous to have ascertained, by analysis, STONE. STO the chemical composition of the substances experimented on ; but as this varies in almost every lo¬ cality, and that in accordance with the superincumbent and surround¬ ing strata, this is of less conse¬ quence in practice than a knowledge of absolute facts in connection with the properties of the material. Experiments to determine the force necessary to fracture, and subsequently to crush, 2-inch cubes of sandstone from the Shipley quarries, Brad¬ ford. The pressure applied in the direction of the cleavaye. No. Weights No. Weights No. Weights of laid on Remarks. of laid on Remarks. of laid on Remarks. Expt in lbs. Expt in lbs. Expt in Ihs. Specimen No. 1. Specimen No. 2. Specimen No. 3. Shipley. Heaton. Heaton Park. 12 31732 11 31732 8 26356 13 33524 fractured 12 33524 fractured 9 28148 10 29940 fractured j 16 38900 crushed 16 40692 crushed l 1 31732 crushed Specimen No. 4. Specimen No. 9. Old Whatley. Specimen No. 10. Manningham-lane. This specimen was de- 11 31732 8 26356 fective and crushed as the 12 33524 9 28148 fractured first weight, 28148 lbs., 13 35316 fractured was laid on. & crushed suddenly. 14 37108 crushed The results of the experiments 1, 2, 3, 9, 10, fractured and crushed in the line of cleavage, are given in the following Table. No. of Specimen Locality. Size. Weight at which it fractured. Weight at which it crushed. 1 Shipley, Bradford. 2-in.cube. 33524 38900 2 Heaton . . . . >> 33524 40692 3 Heaton Park . . 29940 31732 9 Old Whatley . . 35316 35316 10 Manningham-lane. ” 28148 37108 Mean 32090 36749 460 STO STONE. STO Experiments to determine the force required to fracture, and subsequently to crush, 2-inch cubes of sandstone from the Shipley and other quarries, near Bradford. Pressure being applied at right angles to the cleavage. No. of Weights laid on Remarks. No. of Weights laid on Remarks. Expt in lbs. Expt in lbs. Specimen No. 5. Idle Quarry. Specimen No. 6. Jegrum’s-lane. 15 38900 I 18 44276 16 40692 19 45172 fractured. 17 42484 fractured. 18 43380 crushed. 22 47860 crushed. Specimen No. 7. Spinkwell. Specimen No. 8. Coppv Quarry. 10 11 29940 31732 fractured. 14 37108 first fracture. 16 39796 second fracture. 14 37108 crushed. 18 41588 crushed. Specimen No. 11 failed. Results of experiments on specimens 5, 6, 7, 8, fractured and crushed at right angles to the cleavage. No. of Specimen Locality. Size. Weight at which it fractured. Weight with which it crushed 5 Idle Quarry, Brad¬ ford . 2-in. cube 42484 43380 6 Jegrum’s-lane . >» 45172 4-7860 7 Spinkwell. 31732 37108 8 Coppy Quarrv. »» 37108 41588 Mean. 39124 42484 By the foregoing experiment it will be observed that the resisting powers of stone to compression, are greatest when the pressure is applied perpendicularly upon the bed or laminated surface, and are in the ratio of 100 : 82 in the force required to fracture, and 100: 86 in the force required to crush this description of stone. Hence, as already observed, the powers of re¬ sistance of every description of la¬ minated stone, are most effective when the beds are placed horizon- 461 STONE. STO STO tally or perpendicularly to the di¬ rection of the pressure, and this position is the more important when the stone is exposed to the atmosphere, as it partially prevents the absorption of moisture, which in winter tends to destroy the ma¬ terial by the contraction of the stone and the expansion of the water at low temperatures. Experiments to determine the force required to fracture and crush 1 in., ■ 1-J in., and 2 in. cubes of stones, from Scotland, Wales, and other places. • No. of Expl Weight laid on in lbs. Remarks. No. of Expt Weight laid on in lbs. Remarks. Specimen No. 12. Grauwacke. Penmaenmawr, Wales. 2-in. cube. Specimen No. 14. Granite. Mount Sorrel. 2-in. cube. 16 29 30 31 40692 slight fracture. 19 20 21 22 46068 47860 49652 51444 fractured, and after a slight rest crushed. 63988 65780 67572 second fracture. crushed. Specimen No. 15. Grauwacke. Ingleton. 2-in. cube. Specimen No. 16. Granite. Aberdeen. 2-in. cube. 13 20 25 35316 first fracture. 8 9 10 11 26356 27546 28148 28340 fractured. not crushed. 47860 53236 second fracture. not crushed. Specimen No. 17. Syenite. Mount Sorrel. 2-in. cube. Specimen No. 18. Granite. Bonaw. l^-in. cube. 17 18 19 20 42484 44276 46068 47284 crushed. 2 3 7 15604 17396 24564 f fractured into two \ nearly equal parts. crushed. Spec Mtnen No. 19. Furnace Granite. Inverary. 1^-in. cube. Specimen No. 20. Granite. A. 1^-in. cube. 4 5 6 7 19188 20980 22772 24564 crushed. 4 5 6 7 19188 20980 22772 24564 fractured. crushed. 462 STONE. STO STO No. Weight of laid on Remarks. Expt in lbs. Specimen No. 21. Limestone. B. 1^-in. cube. 1 13812 2 15604 3 17396 fractured. 4 19188 crushed. Specimen No. 23. Magnesian Lime¬ stone. Anston. 1-in. cube. 1 2 1258 2154 fractured. To 3050 crushed. Specimen No. 25. Sandstone. 1-in. cube. 8 9 2938 3050 fractured. 13 3498 crushed. No. Weight of laid on Remarks. Expt in lbs. Specimen No. 22. Limestone. C. 1^-in. cube. 2 i 3 ' 4 5 15604 17396 18292 19188 fractured. crushed. Specimen No. stone 1- 24. Magnesian Lime- Worksop. in. cube. 13 14 3834 3946 fractured. 38 7098 crushed. Specimen No. 26. Sandstone. 2-in. cube. 11 12 9770 10218 fractured. 20 12228 crushed. Results of experiments on stone from North Wales and other places. Spe¬ cimens Nos. 12, 14, 17, 18, 19, 20, 21, 22, 23, 24, 25, and 26. No. of Speci¬ men. Description of Stone. Locality. Size. Weight with which it fractured, in lbs. Weight with which it crushed , in lbs. Pressure required to crush a 2in. cube, in lbs. 12 Grauwacke Penmaenmawr... 2 in. cube. 40692 67572 67572 14 Granite ... Mount Sorrel ... 51444 51444 51444 17 Syenite .... tt tt tt 47284 47284 47284 18 Granite ... Bonaw, Inverary lj in. cube. 17396 24564 43669 19 tt Furnace „ 24564 24564 43669 20 tt (A) 22772 24564 43669 21 Limestone (B) 17396 19188 34112 22 tt (C) J) 18292 19188 34112 23 tt Anston. 1 in. cube. 2154 3050 12200 24 tt Worksop. 3946 7098 28392 25 Sandstone ... ... tt 3050 3489 13992 26 if . 2 in. cube. 10218 12228 12228 463 STONE. STO STO The Welsh specimen of grau¬ wacke, from Penmaemnawr, ex¬ hibits great powers of resistance, nearly double that of some of the Yorkshire sandstones, and about one-third in excess of the gra¬ nites, excepting only the granite from Mount Sorrel, which is to the Welsh grauwacke as -7571 : 1. Some others, such as the Ingleton grauwacke, supported more than the granites, but are deficient when compared with that from Penmaen- mawr. The specimen No. 23 is the stone of which the Houses of Parliament are built. Specimens Nos. 25 and 26 were broken to show experimentally the ratio of the powers of resistance as the sixe is changed. The results are suf¬ ficiently near to prove that the crushing weights are as the areas of the surface subjected to pres¬ sure. The specific gravity and poro¬ sity of the different kinds of rock vary greatly : those from the neigh¬ bourhood of Bradford were carefully tested in regard to their powers of absorption; the experiments, which were conducted by Mr. Fairbairn with great precision, gave the following results :— Experiments to ascertain the amount of water absorbed by various kinds \ of stone. No. of Specimen. Description of Stone. Locality. Weight before im¬ mersion. W eight after im¬ mersion for 43 hours. Differ’nce of Weight. Proportion absorbed. 1 Sandstone Shiplev. lbs. 5-4687 5-5546 •0859 1 in 63-6 2 Heaton. 5 2578 5-3632 •1054 1 in 49-8 3 >> Heaton Park . 5-1718 5-2896 •1171 1 in 44-1 4 »» Spink well. 5-2968 5-4726 •1758 1 in 301 5 Idle Quarrv. 5-7178 5-8203 •1016 1 in 56-3 6 Jegrum’s-lane .... 5-5976 5-7187 •1211 1 in 46-2 7 >> Spinkwell. 5-6757 5-7851 •1094 1 in 53-81 8 Coppy Quarry .... 5-5703 5-6914 •1211 1 in 46t 9 >9 Old Whatley. 5-4726 5-6132 •1406 1 in 3&-t; 10 yy Manr.ingham-lane 5-4882 5-6093 •1211 1 in 46-: 11 yy yy yy 5-6289 5-7539 •1250 1 in 45 f 12 Grauwacke Wales . 6-4101 6-4140 •0039 1 in 1641 ( 13 Granite .. Mount Sorrel .... 5-6875 5-6992 •0117 1 in 485-1 14 yy yy yy 5-8007 5-8124 •0117 1 in 495 1 15 Grauwacke Ingleton . 5-7500 5-7539 •0039 1 in 1962-6 From the above table it will be observed that specimen No. 15, the Ingleton grauwacke, is the least absorbent, and No. 12, the Welsh grauwacke, absorbs almost as little, while Nos. 9 and 14 of the sandstones absorb most. The granites, though closely granu¬ lated, take up much more watei than the grauwackes, but less thari the sandstones. The resistance o the grauwacke specimens to the admission of water is four time; that of the granite, and thirty-si> times that of sandstone, such a is found in the Yorkshire quarries STO STONE. STO J © 1 o. GC o 6 ! Description of Stone. Locality. Size. Speci¬ fic gra¬ vity. Pres¬ sure to frac¬ ture speci¬ men Pres¬ sure to crush speci¬ men. Pres¬ sure per square inch to crush speci¬ men. Cubic feet in a ton. Ratios of powers of absorp¬ tion. i Sandstone Shipley. cube 2 in. 2452 lbs. 33524 lbs. 38900 lbs. 9725 14-616 1 in. 63*6 2 Heaton. „ 2420 33524 40692 10173 14-809 49-8 3 Heaton Park ... 2-385 39940 31732 7933 15027 441 4 5 ” Spinkwell. Idle Quarrv. )) 2-329 2-484 defec- 42484 tive 43380 10845 15-388 14"545 301 56-3 ! 6 •Jegrum’s-lane ... Spinkwell. 2-400 45172 47860 11965 14-933 46-2 7 2-458 31732 37108 9277 14-592 53-8 8 Coppv Quarrv ... 2-408 37108 11688 10397 14-833 46-0 1 9 Old Whatley ... 2-415 35316 35316 8829 14-840 38-9 10 Manning’m-lane 2-401 28148 37108 9277 14-927 46-3 11 2-421 fai led. 14-804 450 12 Grauwackt- Penmaenmawr 2-748 40692 67572 16893 13-042 1641-0 f 13 Granite . . Mount Sorrel 2-857 13-489 485-3 14 2-675 51444 51444 12861 13-389 4950 | 15 Grauwacke Ingleton . 2-787 35316 (53236) not crd 12-866 1962-6 18 Granite ... Aberdeen . — 27546 (2S340) not crd — — 1 17 Syenite .. Mount Sorrel ... — 47284 47284 11821 — — J 18 Granite .. Bonaw . l^in. — 17396 24564 10917 — — 19 Furnace . — 24564 24564 10917 — — 20 A . — 22772 24564 10917 — — I 21 Limestone B . — 17396 19188 8528 — — 22 C . — 18292 19188 8528 — — 1 23 Anston . 1 in. — 2154 3050 3050 — — 24 Worksop . » — 3946 7098 7098 — — . 25 Sandstone D . — 3050 3498 3498 — — 28 » E . 2in. — 10218 12228 3057 — — On comparing the results of the experiments on the Yorkshire sandstones, it will be seen that the difference of resistance to pressure does not arise so much from the variable character of the stone in different quarries, as from the position in which it is placed as regards its laminated surface, the difference being as 10:8 in favour of the stone being crushed upon its lied to the same when crushed in the line of cleavage; the same may be said of the lime¬ stones. Comparing the strengths indi¬ cated by the above experiments, there is found to be a very close approximation in the granites, but considerable difference in the Yorkshire sandstones. Mr. Rennie obtained his specimens from the same district, the valley of the Aire; but the force required to crush the Bromley Fall stone was much less than that required to fracture similar specimens from the Shipley quarries. The follow¬ ing table gives some useful re¬ sults for comparison. From the above it is evident that there is a considerable differ¬ ence between the results of Mr. Rennie’s experiments and those in the preceding tables. This may, perhaps, be due to the different methods pursued in the experi¬ ments, or from taking the first appearance of fracture as the ulti¬ mate power of resistance. Where¬ as there is in some cases a differ¬ ence of nearly a third between the weight required to produce the first crack, and that required 465 STONE. STO subsequently to crush the speci¬ men. This is the more remark¬ able, as all the specimens did not appear to follow the same law, STO as in some the weight which frac¬ tured the specimen by a continua¬ tion of the process ultimately crushed it. Description of Material. Crushing force in lbs. per square inch. Authority. Porphyry. 40416 Gauthey. Granite, Aberdeen . 11209 Rennie. „ mean of 3 varieties .. 11564 Experiments 14, 18, 19. Sandstone, Yorkshire. 6127 Rennie. „ „ mean of 9 9824 Experiments 1 to 9. Brick, hard. 1888 Rennie. „ red . 805 Rennie. The necessity of these experi¬ ments was more apparent some years since, in the construction of the Britannia and Conway tubu¬ lar bridges, when fears were enter¬ tained of the security of the ma¬ sonry to support, upon the given area, the immense weight of the tubes, upwards of 1,500 tons, resting on one side of the tower. To ascertain how far the material (Anglesea limestone) was calcu¬ lated to sustain this load, the fol¬ lowing experiments were made :— Brickwork. No. 1.—9-in. cube of cemented brickwork (Nowell and Co.), No. 1 (or best quality) weighing 54 lbs., set between deal boards. Crushed with 19 tons 18 cwt. 2 qrs. 22 lbs. “551-3 lbs. per sq. inch. No. 2.—9-in. cube of brickwork, No. 1 weighing 53 lbs., set in ce¬ ment, crushed with 22 tons 3 cwt. 0 qr. 17 lbs. ~ 612-7 lbs. per sq. inch. No. 3.—9-in. cube of brickwork, No. 3 weighing 52 lbs. set in ce¬ ment. Crushed with 16 tons 8 cwt. 2 qrs. 8 lbs. 454-3 lbs. per sq. inch. No. 4.—9J-in. brickwork, No. 4 weighing 55jibs., set in cement. Crushed with 21 tons 14 cwt. 1 qr. 17 lbs. “568'5 lbs. per square inch. No. 5.—9-in. brickwork, No. 4 weighing 54Jibs., set between boards. Crushed with 15 tons 2 cwt. 0 qr. 12 lbs. “417 lbs. per sq. inch. Mean of the above experiments — 521 lbs. per sq. inch. The last three cubes of common brick continued to support the weight, although cracked in all di¬ rections ; they fell to pieces when the load was removed. All the brickwork began to show irregular cracks a considerable time before it gave way. The average weight supported by these bricks was 33-5 tons per square foot, equal to a column 583 69 feet high, of such brick¬ work. Sandstone. No. 6.—-3-in. cube red sand¬ stone, weighing 1 lb. 14| oz., set between boards (made quite dry by being kept in an inhabited room). Crushed with 8 tons 4 cwt. 0 qr. 19 lbs. = 2043 lbs. per sq. inch. No. 7.—3-in. cube sandstone, j weighing lib. 14 oz., set in ce- I ment (moderately damp). Crushed with 5 tons 3 cwt. 1 qr. 1 lb. = 1285 lbs. per sq. inch. No. 8.—3-in. sandstone, weigh¬ ing lib. 15J-oz., set in cement l (made very wet). Crushed with 466 STO STONE. STO with 4 tons 7 cwt. 0 qr. 21 lbs. “ 1085 lbs. per sq. inch. No. 9.—6-in. cube sandstone, weighing 18 lbs., set in cement. Crushed with 63 tons 1 cwt. 2 qrs. 6 lbs. zz 3924-8 lbs. per sq. inch. No. 10.-—9£-in. cubes and stone, weighing 58|lbs., set in cement (77) tons were placed upon this without effect, = 2042 lbs. per sq. inch, which was as much as the machine would carry). Mean of the above experiments ~ 2185 lbs. per sq. inch. All the sandstones gave way sud¬ denly, and without any previous i cracking or warning. The 3-in. cubes appeared of ordinary de¬ scription ; the 6-in. was fine grained, and appeared tough and of supe¬ rior quality. After fracture the upper part generally retained the form of an inverted square pyra¬ mid about 2) in. high and very symmetrical, the sides bulging away in pieces all round. The average weight of this material was 130 lbs. 10 oz. per cube foot, or 17 feet per ton. The average weight required to crush this sandstone is 134 tons per square foot, equal to a column 2351 feet high of such sandstone. Limestone. No. 11.—-3'in. cube Anglesea limestone, weighing 2 lbs. 10 oz. set between boards. Crushed with 26 tons 11 cwt. 3 qrs. 91bs.zz 6618hbs. per sq. inch. This stone formed numerous cracks and splin¬ ters all round, and was considered crushed; but on removing the weight about two-thirds of its area were found uninjured. No. 12.—3-in. limestone, weigh¬ ing 2 lbs. 9 oz., set between deal boards. Crushed with 32 tons 6 cwt. 0 qr. 1 lh. — 8039 lbs. per sq. inch. This stone also began to ! splinter externally with 25 tons (or 6220 lbs. per sq. in.), but ulti¬ mately bore as above. No. 13.—3-in. limestone, weigh¬ ing 2 lbs. 9 oz., set in deal boards. Crushed with 30 tons 18 cwt. 3 qrs. 24 lbs. = 7702-6 lbs. per sq. inch. No. 14.—Three separate 1-in. cubes of limestone, weighing 2 lbs. 9 oz., set in deal boards. Crushed with 9 tons 7 cwt. 1 qr. 14 lbs. ----- 6995-3 lbs. per sq. in. All crushed simultaneously. Mean of the above experiments, 7579 lbs. per sq. inch. All the limestones formed per¬ pendicular cracks and splinters a long time before they crushed. Weight of the material from above "165 lbs. 9 oz. per cubic foot, or 13 ) feet per ton. The weight required to crush this limestone is 471*15 tons per square foot, equal to a column 6,433 feet high of such material. Previously to the experiments just recorded, it was deemed ad¬ visable not to trust to the resisting powers of the material of which the towers of either bridge were composed; and, to make security doubly sure, it was ultimately ar¬ ranged to rest the tubes upon ho¬ rizontal and transverse beams of great strength, and by increasing the area subject to compression, the splitting or crushing of the masonry might be prevented. This was done with great care, and the result is the present stability of those important structures. To the consideration of the prac¬ tical builder the general summary of results on the next page is submitted, obtained from various materials, showing their respective powers of resistance to forces tending to crush them. Professor Hodgkinson has also experimented on round and square columns of sandstone from Ped Delph, Littleborough, Lancashire, a much harder stone than that found on the banks of the Aire. With regard to these experiments, it appears “ that there is a falling off in strength in all columns from 467 STONE. STO STO General Summary of Results on Compression. Crushing Description of Material. force in lbs. Authority. persq.inch. Cast steel.• Blister steel. Iron Cast iron (white derived ) Fairbairn’s Experiments on and from 14 meltings) . . 214816 the Mechanical Properties Steel. Ditto (from 12 meltings) . 163744 of Metals.—Transactions Ditto (from ordinary cast- of the British Association, ings). 89600] 1854. ( Porphyrv. 40416 Gauthey. Grauwacke, Penmaenmawr 16893 Experiment No. 12. Granite, mean of 3 . . . 11565 Ditto Nos. 14, 18, 19. Sandstone, Yorkshire . . 6127 Rennie. Ditto, mean of 9 exprmts . 9824 Experiments 1 to 10. Stone. Ditto, Runcorn . . . . 2185 Clark. Limestone. 8528 Experiments 21, 22. Ditto, Anglesea . . . . 7579 Clark. Ditto, Magnesian—mean . 5074 Experiments 23, 24. Brick, hard. 1888 Rennie. Ditto, red. 805 \ Ditto, mean of 4 exprmts. 1424 Clark. /Box. 9771N English Oak (dried) . . 9509 Ash (ditto) . . 9363 Timber. 1 Plum-tree (ditto) . . Beech. 8241 6402 Hodgkinson. Red Deal. 5748 Cedar . 5674 ^ Yellow Pine. 5375/ the shortest to the longest, but that the diminution is so small, when the height of the column is not greater than about twelve times the side of its square, that the strength may be considered uni¬ form, the mean being 10,000 lbs. per square inch or upwards. “ From the experiments on the columns 1 in. square, it appears that when the height is fifteen times the side of the square, the strength is slightly reduced ; when the height is twenty-four times the height of the base, the falling-ofF is from 138 to 96 nearly; when it is thirty times the base, the strength is reduced from 138 to 75; and when it is forty times the base, the strength is reduced to 52, or to 468 little more than one-third. These numbers will be modified to some extent by experiments now in pro¬ gress. “ As long columns always give way first at the ends, showing that part to be weakest, we might eco¬ nomize the material by making the areas of the ends greater than that of the middle, increasing the strength from the middle both ways towards the ends. If the areas of the ends be to the area of the middle, as the strength of a short column is to that of a long one, j we should have for a column, whose height was twenty-four times the breadth, the areas of the ends and middle as 13,769 to 9595 nearly. This, however, would make the STO STONE-COAL FURNACES. STO ends somewhat too strong, since the weakness of the long columns arises from their flexure. “ Another mode of increasing the strength would be that of prevent¬ ing flexure, by increasing the di¬ mensions of the middle. “ From the experiments it would appear that the Grecian columns, which seldom had their length more than about ten times the diameter, were nearly of the form capable of bearing the greatest weight when their shafts were uniform, and that columns tapering from the bottom to the top were only capable of bearing weights due to the smallest part of their section, though the larger end might serve to prevent lateral thrusts. This latter remark applies, too, to the Egyptian co¬ lumns, the strength of the column being only that of the smallest part of the section. “ From the two series of experi¬ ments, it appeared that the strength of a short column was nearly in proportion to the area of the sec¬ tion, though the strength of a larger one is somewhat less than in that proportion.” These extracts from Mr. Hodg- kinson’s paper show the advantages to be derived from proper attention to the construction of columns, not only as regards their resistance to a crushing force, but as to the pro¬ priety of enlarging the ends to in¬ crease their powers of resistance. Experimental data cannot always he applied in architectural construc¬ tions ; but it is, nevertheless, essen¬ tial that the architect and builder should be cognizant of the facts, in order that they may prepare their plans, as far as possible, in accor¬ dance with them, and effect the greatest amount of work with the least waste of material. Stone - Coal Furnaces — Anthracite Furnaces (American). In eastern Pennsylvania more than sixty blast¬ furnaces, supplied by anthracite, are most generally in operation. These produce on an average from seventy-five to eighty tons of iron per week. This immense number of furnaces, supplied by stone coal alone, was the result of ten years’ industry; and the perfection to which they have been brought is a security that nothing can check their use,or prevent their extension. Anthracite furnaces resemble, to a greater or less degree, coke and charcoal furnaces. They are sel¬ dom so high as coke furnaces, and their horizontal dimensions are usually greater than those of char¬ coal furnaces. The following are the dimensions of several of the furnaces recently erected in eastern Pennsylvania. One belonging to Mr. Ecket, at Reading, is 37| feet in height; the top or throat 6 feet in diameter; height of hearth, 5 feet; tuyeres, 22 inches above its bottom: the hearth is 5 feet square at the base, and 6 feet at the top; the boshes are inclined 67|°, or at the rate of 6 inches to the foot, and measure 14 feet at their largest diameter. At the point where the slope of the boshes joins the lining, a perpendicular cylindrical space, 5 feet in height, commences, and from this point the general taper to the throat is continued in a straight, line. The hearth, as well as the boshes, is built of coarse standstone. but the latter are covered with a lining of fire-brick, 9 inches thick. The in-wall consists of two linings, and the interior is the lining which covers the boshes; outside of this is a space 4 inches wide, filled with coarse sand, and this is protected by a rough lining of slate, 2 feet thick. The rough walls of the stack are not heavy, but they are well secured by binders. Two furnaces erected at the Crane Works, near Allentown, may be considered as the greatest im¬ provement. The stack is 35 feet high, 40 feet square at the base, and at the top 33 feet. This furnace is therefore but slightly tapered, 469 x STO and requires heavy stonework. It generates steam from the trunnel- head gas flame. At most anthra¬ cite furnaces, this is done by putting the boilers on the top of the fur¬ nace. The hearth is 5 feet high, 4 feet ’square at the bottom, and 6 feet at the top; the inclination of the boshes is 75°, and the cylin¬ drical part of the in-wall above the boshes is 8 feet high and 12 feet in diameter. From the cylindrical part up to the top, which is 6 feet in width, the in-wall runs in a straight line. A furnace erected by Messrs. Reeves and Co., at Phoenixville, is 34 feet in height: the hearth is 6 feet high, 4 feet 3 inches square at the bottom, and 5 feet 3 inches at the top: the boshes taper 68°, or at the rate of rather less than 6 inches to the foot: they measure 13 feet at the widest part. Great care is taken that the lining and the boshes form a gradual curve, that sticking and scaffolding in the boshes may be obviated. The top of this furnace is 8 feet square. There is no doubt that the form and construction of these anthracite furnaces have been carried, within the short space of a few years, to so high a state of perfection as to leave but little room for future im¬ provements. Their shape is worthy of imitation, particularly by Western manufacturers; for coal adapted to all of these furnaces is abundant in the western States of America. Most of these furnaces generate the steam for the motive power of the blast as well as the heat for the hot-blast apparatus at the top of the furnace. In this way expense is not only saved, but a uniform genera¬ tion of steam and heating of air are produced. The cost of erecting such a furnace cannot be readily estimated, as it must depend greatly upon locality, material, w r ages, and individual tastes; but it may be laid down as a general rule that a stone-coal furnace costs less than STO a coke furnace, and that, in most cases, a good charcoal stack can be altered so as to serve for stone coal. In the Western States, many charcoal furnaces are in operation, and there is no limit to their ex¬ tension, so far as raw material, wood and ore are concerned. One circumstance, however, will neces¬ sitate the introduction of stone-coal furnaces in the West, namely, the price of charcoal iron. Some lo¬ calities can successfully compete against stone-coal iron; but those which, besides enjoying that ad¬ vantage, are situated near navi- I gable streams or canals, are very few in number. It is said that the average cost of producing char¬ coal pig at Pittsburgh is 20 dollars; some furnaces produce it at a cost of 15 dollars: in as many cases, however, 25 dollars is paid for iron. The market price at Pittsburgh varies from 25 to 30 dollars, ac¬ cording to quality; and at this price little profit is left to the owners of I the furnaces. How far the stone- coal furnaces are in advance of this will be shown by the following statement of the average result of three years’ smelting. This state- j ment was furnished by Mr. Reeves, ( of Philadelphia. Amount of material consumed to pro¬ duce one ton of iron at anthracite furnace No. 1, at Phoenixville. Tons. Iron ore .... 2-59 Anthracite coal . . 1-83 Lime.1’14 Amount consumed at furnace No. 2, at the same place. Tons. Iron ore .... 2’65 Anthracite coal . . 1-89 Lime.1*15 These furnaces smelt brown he¬ matite, hydrated oxide of iron. The wages for producing one ton of anthracite iron, including ail inci¬ dental expenses, amount to 2 dollars STONE-COAL FURNACES. 470 STONE OCHRE. STO 50 cents, to which is to be added the interest on capital employed. Anthracite furnaces require wider tops than coke furnaces, while the latter require far wider tops than charcoal furnaces. This width of the top may be considered the most essential improvement on the blast¬ furnace which is supplied by an¬ thracite coal. The height of the stack in anthracite is much less than in coke furnaces, and some¬ what lower than in charcoal fur¬ naces. Anthracite furnaces vary from 30 to 35feet in height; char¬ coal furnaces, from 30 to 40 feet in height; and coke furnaces from 40 to 60 feet. The width of the trunnel-head varies, in the United States, considerably. In Pennsyl¬ vania, Ohio, Kentucky, and Ten¬ nessee, the width of furnaces at the boshes is 9 and often 10 feet, and at the top from 18 to 20 inches ; or in the proportion of 30 square feet at the boshes to 1 square foot at the top. The Cold Spring fur¬ nace measures at the boshes 9 feet, and at the top 32 inches: here the proportion is 11 feet at the boshes to 1 foot at the top. The dimensions of charcoal fur¬ naces in Europe which smelt re¬ fractory ores, are generally in the proportion of 5 feet at the boshes to 1 foot at tbe throat; frequently in the proportion of 4 to 1. In coke furnaces, the proportion of the horizontal section of the boshes to that of the top is seldom less than 4 to 1, though sometimes even 2-5 to 1. In anthracite furnaces, the diameter of the throat is 6 feet, and that of the boshes 12 feet; that is, in the proportion of 1 to 4. But sometimes the boshes measure 13 and the tops 8 feet square : in this case, the proportion is as 2 to 1. Taking into consideration the small height of the stack, and the strong blast which is applied, it is found that this arrangement in anthracite furnaces is, in an economical point of view, very favourable; for, in- STO stead of retarding, it facilitates the vent of the gases. Narrow tops answer where loamy ore and soft coal are used; but, in such cases, to obtain favourable results, weak blast and high stacks should be employed. But these conditions can be observed only where coal and labour are cheap. If any doubt exists concerning the proper di¬ mensions of a furnace, the best course is to commence with a comparatively low stack, wide throat, and with as high a pressure in the blast as the fuel will pos- j sibly bear. Stone ochre. The true stone ochres { are found in balls or globular j masses of various sizes, in the solid j bodies of stones lying near the sur- j face of rocks among the quarries in i Gloucestershire or elsew here. These I balls are of a smooth compact tex- J ture, in general, free from grit, and j of a powdery fracture; they vary J exceedingly in colour, from yellow to brown, murrey, and grey, but do not differ in other respects from the Oxfordshire ochre, and may be safely used in oil or water in the several modes of painting, and for browns and dull reds in enamel. Stools, pieces of plank fastened to a ship’s side to receive the bolting of the gallery. Stopper-bolts,large ring-bolts drove in the deck of a ship before the main- hatch, for the use of the stoppers. Stopping, in mining, cutting down mineral ground with a pick. Stories, in architecture. Palladio di¬ rects that the height of the story immediately above the principal floor be a sixth part less than that below; and if there be an attic, or third story, if should be nine- twelfths of the height of that im¬ mediately under it. Stoup, an old English term for the holy-water basin placed at the en¬ trance to a church: it is applied also to a vessel for carrying about and distributingholy-water amongst a Roman Catholic congregation. x 2 471 STR STRENGTH OF MATERIALS. STU Stra/ce, in ship-building, one range of planks fore and aft. Strap, in carpentry, an iron plate placed across the junction of two or more tirrbers, either branched out or straight, as may be found requisite, and each branch bolted or keyed with one or more bolts or keys, through each of the timbers, for the purpose of securing them together. Strata, in geology, extensive layers of any mineral substance, such as rocks, etc. Secondary strata are nearly all comprised under the heads of sandstone, limestone, and shale. Streamers, in mining, the persons who work in search of stream-tin. Stream-tin, in mineralogy, particles or masses of tin found beneath the surface of alluvial ground, and se¬ parated from the earthy matter by passing a stream of water over it: hence the name. Strength and stress of materials. The works of Barlow and Tredgold con¬ tain the most useful information on these subjects. Barlow shows that there are four distinct strains to which every hard body may be exposed, and which are,—1st, a body may be pulled or torn asun¬ der by a stretching force, applied in the direction of its fibres, as in the case of ropes, stretchers, king¬ posts, tie-beams, etc.; 2ndly, it may be broken across by a trans¬ verse strain, or by a force acting either perpendicularly or obliquely to its length, as in the case of levers, joists, etc.; 3rdly, it may be crushed by a force acting in the direction of its length, as in the case of pillars, posts, and truss- beams ; 4thlv, it may be twisted or wrenched by a force acting i« a circular direction, as in the case of the axle of a wheel. Stretching-course, in brickwork and in masonry, a row or course in which the bricks or stones are placed with their longest faces ex¬ posed to view'. The bricks or stones thus laid are called stretchers; and those disposed with the ends out¬ wards are called headers. Strigce, in ancient architecture, what are now r called flutings. String, in mining, a small vein. String, the strake under the gunwale withinside, generally worked the same thickness as the sheer-strake, and scarfed in the same manner: the string and sheer-strake are bolted through a ship’s side. String-course, a narrow, horizontal, and slightly projecting course of brickwork or masonry in the wall of a building. Stucco, in architecture, a composition of white marble pulverized and mixed with plaster or lime, but the ingredients vary; it is employed commonly for facing exterior and interior works; it is also sometimes used for floors Stuck or Wulfs oven, a furnace for the reduction of iron, at one time common in Europe, now little em¬ ployed. The interior of this fur¬ nace has the form of twm cones united at their bases: it is usually from 10 to 16 feet high, 24 inches wide at bottom and top, and 5 feet i at the centre. There are generally two tuyeres, both on the same side. The opening called the breast is closed after the furnace is heated, after which, charcoal and ore are thrown in, and the blast introduced. As soon as the ore passes the tuyere, iron is deposited at the bottom of the hearth: when this amounts to a ton, the blast is stopped, the breast £ w'all removed, and the metal lifted out in a solid mass, or stuck, wulf, as it is called by the Germans. Studding-sails, in navigation, certain light sails extended beyond the skirts of the principal sails in mo¬ derate steady breezes; named also i| ‘ goose-wings.’ Studies. In painting, these signify j works which a painter undertakes, to acquire a practical knowledge |l of his art and facility of execution. II The term is also applied to the 1 472 SULPHUR. STU SUL parts taken separately, which the artist afterwards transfers to the picture. Stuffing-boxes, in a locomotive engine, those with recesses for admitting some soft material, such as white spun-yarn, to render steam-tight | any rod working through this stuff¬ ing or packing. The piston-rods, slide-valve rods, regulator-rods, and pump-plunger, all work through stuffing-boxes of this description. Stull, timber placed in the backs of bevels and covered with boards, or small piles, to support rubbish. * Sturt, in mining: when a tributer takes a pitch at a high tribute, and cuts a course of ore, he sometimes gets two, three, or five hundred pounds in two months: this great profit is called ‘ a sturt.’ Styles of early Architecture in Eng¬ land. The several examples, usually denominated Gothic, are as follows: 1. The Anglo-Roman, which existed about 300 years. 2. The Anglo- Saxon, about 450 years. 3. The Anglo-Norman ( which continued in use even on the introduction of the Pointed style), about 85 years. 4. Early Pointed ( termed also the Lan- \ cet style and early Eiglish), about 140 years. 5. The Pointed style (called by some pure Gothic), about 110 years. 6. The Florid Pointed (termed also the Perpendicular), about 140 years. 7. The Tudor, Elizabethan, and Stuart. Stylobate, the substructure of a Greek temple below the columns, some¬ times formed of three steps, which were continued round the peristyle; and sometimes of walls raised to a considerable height, in which case it was approached by a flight of steps at one end. Subtangent, in geometry, in any curve is the line which determines the intersection of the tangent in the axis prolonged. Subtense, in geometry, the chord of an arch; that which is extended under anything. Sucker, in mechanics, the embolus or piston of a pump. In pneumatics, a round piece of leather, which laid wet on a stone and drawn up in the middle, leaves a vacuum within, which, by the pressure of the atmosphere, makes it adhere. Sulphate of copper (blue vitriol), in chemistry, metallic salt, a com¬ pound of sulphuric acid and copper. Sulphate of iron (copperas or green vitriol), in chemistry, a metallic salt, a compound of sulphuric acid and iron. Sulphate of lead, an exceedingly white precipitate from any solution of lead by sulphuric acid, much re¬ sembling the blanc d'argent, and which has, when well prepared, quite neutral, and thoroughly edul¬ corated or washed, most of the pro¬ perties of the best white-leads, but is rather inferior in body and per¬ manence. Sulphate of lime (gypsum, etc.), in mineralogy, a compound of sul¬ phuric acid and lime. Sulphate of zinc (white vitriol), in chemistry, a metallic salt, a com¬ pound of sulphuric acid and zinc. Sulphur, a simple combustible sub¬ stance found native in a loose pow¬ der, either detached or in veins. It is met with in the neighbourhood of volcanoes, where it is deposited as a crust on stones contiguous to them. It can be prepared by ex¬ posing iron pyrites to heat, when part of the sulphur is driven off in vapour, and may be collected in water: when vaporized, it condenses in small crystalline particles, called flowers of sulphur. It is inflam¬ mable, burning slow with a pale blue flame. Sulphur is found in connection with silver, copper, lead, antimony, and iron. Sulphur oc¬ curs, in nature, crystallized in acute octohedrons with rhombic bases. It is principally brought to this country from Sicily. Sulphuret of hydrogen. This gas, com¬ monly known as sulphuretted hy¬ drogen, is invaluable as a re-agent in separating one class of metals 473 SUL SURVEYING. SUR from another, is precipitated by it in acid solutions from another gas, and only acted upon by it in alka¬ line solutions. Sulphurets of iron. —Iron has a very great affinity for sulphur: there are five definite compounds of these substances. It is very difficult to separate iron from sulphur by heat alone. Of the five different com¬ positions, two only deserve atten¬ tion,—the white and yellow sul¬ phurets. White mlphuret of iron (white pyrites) abounds in coal-beds, and in the accompanying strata of clay; also in regular veins, along with ores of lead, copper, and iron, in the transition rocks. Before the flame of the blow-pipe, it becomes red ; upon charcoal, the sulphur is evaporated, and oxide of iron re¬ mains. It is very liable to decom¬ position : it is preferable to the yellow kind in the manufacture of copperas, and is, in coal-mines, the most dangerous of any, as it often decomposes so quickly as to kindle the coal-slack. Its composition is, in 100 parts, 45-07 iron. 53-35 sulphur. 9 - 58 manganese. 99-00 white pyrites. Yellow sulphuret of iron, yellow pyrites. —This variety becomes red before the blow-pipe; and in the reducing flame it melts into a glo¬ bule, which continues red-hot for a short time, and possesses, after cooling, a crystalline appearance. In nitric acid it is slowly soluble, with the precipitation of sulphur, but in no other acid. It is com¬ posed of 47-30 iron. 52 - 70 sulphur. 100-00 yellow pyrites. Yellow pyrites is almost identical with the white pyrites, and the lat¬ ter appears to be only different in containing more foreign matter: both are widely diffused among the ores of iron, and are found in mas¬ sive nodules, crystals, and veins, in the coal-beds, clay-slate, grau- wacke, greenstone, limestone, and in beds of primitive slate. It is the main material which is used for manufacturing copperas, alum, oil of vitriol, Spanish brown, and sul¬ phur. Summer, a horizontal beam or girder. Sump, in mining, a pit sunk in the engine-shaft below the lowest work¬ ings. Sump-shaft, the engine-shaft. Supercilium, the transverse airtepag- ment of a doorway. The word is also used to denote the small fillets or bands above and below the scotia of the Ionic base. Superficies, in geometry, the surface of any body or figure, considered as possessing two dimensions, or extension in length and breadth, but destitute of thickness : in men¬ suration, it is estimated as area. Supporters, in heraldry, figures stand¬ ing on a scroll and placed by the escutcheon, such as the lion and the unicorn in the British, and the angels in the French arms. Supporters, in ship-building, the knee-pieces under the cathead. Surmarks, in ship-building, the sta¬ tions of the ribbons and harpings which are marked on the timbers. Surveying is the art of applying the principles of geometry and trigo¬ nometry to the measurement of land. The principal operations are laying down or driving base lines, and triangles on either side of the base. In large surveys it is de¬ sirable to lay down these triangles by measuring each angle with an instrument called the theodolite, by which the accuracy of the measure¬ ment of the sides may be checked. The theodolite is also avail¬ able in fixing the true position of points, the distances between which are immeasurable, owing to the intervention of buildings, rivers, or 474 sus SUSPENSION. SUS other obstacles. Rectangular or irregular areas of land are similarly reduced to triangles, and their exact position referred to a haSte line. In driving lines over land, three long poles are requisite: these are ranged in the direction of the intended line at the greatest distance at which they can be seen, either with the naked eye or with the as¬ sistance of a telescope, and driven firmly into the ground. Interme¬ diate stakes are then fixed, by which the line is marked out. In proceeding onward to extend the line included between the front and back pole, the latter only is re¬ moved, and carried before the front pole to the greatest practicable dis¬ tance, and being ranged by the two remaining poles, is there driven. Thus the middle pole becomes the back one, and is in like manner removed to the front, and there ranged and fixed: and in this i manner, by successively removing the back pole, and conveying it to the front, the line is extended as far as necessary. These poles should be as light as possible, consistent with strength, and shod with iron points, to facilitate driving. On the top of each pole a flag or disk is fixed, to render them conspicuous from a long distance. Distances are measured with a chain formed of wire links, the length of the chain being 66 feet, and formed with 100 links, each link measuring 7‘92 inches. The end of each chain is marked by driving a wire pin or I arrow into the ground, by counting which the number of chains mea¬ sured is ascertained. The base line being thus driven and measured, it is recorded in a book, and all intersections of fences, etc., marked, and their relative distances on the base are entered. A distant point on either side of the base is then determined, and a pole erected upon it, and the distance of this point from two fixed points upon the base measured with the chain, and duly recorded. By this means, a triangle is completed, and after¬ wards correctly filled in with all intervening fences, etc.; and by re¬ peated processes of this kind the survey is extended to any required distance on each side of the base. If the triangles first laid down are of great extent, they should be de¬ termined, and the position of their angles ascertained with the theodo¬ lite. This instrument consists of a pair of horizontal circular plates, the upper of which is called the vernier plate, turning freely on a centre upon the lower plate, the edge of which is chamfered off, and accurately graduated with degrees and subdivisions. By these plates and their adjusting screws, etc., horizontal angles are measured, the sight of the surveyor being aided by a powerful telescope on the upper part of the instrument, and a microscope to read off the gradu¬ ations upon the vernier. An upper frame which carries the telescope also supports a vertical arc or semi¬ circle, w’hich is likewise graduated, and with the aid of another mi¬ croscope the elevation of any high object, as a tower, etc. (observed through the telescope) may be cor¬ rectly read otF. This part of the apparatus thus enables vertical an¬ gles to be measured, and by the application of trigonometry, heights or distances may be thus exactly determined without the actual mea¬ surement of all the lines in each vertical triangle. Suspension, in mechanics, as in a balance, are those points in the axis or beam where the weights are applied, or from which they are suspended. Suspension. Bridges of suspension are of several kinds and of various dimensions, consisting of several iron chains, not formed of small links, like cables, but of whole bars of iron jointed at their ends, passed over a tower, being the access to the bridge on each side of the river, 475 SWE SYMPIESOMETER. SYPl while their extreme ends are firmly attached to large and ponderous stones that are sunk a great depth into the ground on each side of the stream. These masses of masonry are named abutments. The chains hang in parallel festoons over the river, between the supporting tow¬ ers, and carry a number of vertical bars of iron that are attached to and hang down from them for the pur¬ pose of suspending beams of wodd or iron hanging horizontally in the direction of, or obliquely to, the stream, and serving as joists to support a strong planked platform or roadway that extends across the river: frequently these roadways are paved, or at least gravelled or ballasted over for horses, carriages, and pedestrians. Extraordinary ex¬ amples exist of this species of build¬ ing in our own country, viz. that at Bangor, crossing the Menai Strait, by Telford,—that at Hammersmith, by Tierney Clark,—Hungerford, by Brunei; but the most extraordi¬ nary structure is the stupendous work of Tierney Clark, uniting Pesth with Buda, in Hungary. Mr. Dredge has constructed several smaller bridges of suspension, ac¬ cording to his arrangement, both in England and Scotland. Suspen¬ sion bridges have been constructed also with wire as a material at Fribourg, in Switzerland, and at other places. Sweep , or Tiller-Sweep, a circular plank fitted to support the fore¬ most end of the tiller, or handle of a rudder, much improved by con¬ veying the tiller-rope round it, and keeping it always tight. Swivel, in mechanics, something fixed in another body so as to turn round on it; a kind of ring made to turn round in a staple or other ring. In artillery, a very small cannon, which carries a shot of about half a pound. Sycamore, a species of Ficus, or fig- tree, common in Egypt and other parts of the East; its timber is of little value. The name is also ap¬ plied to a species of maple, the Acer Pseudo-Plat anus, a native of the nfMdle and south of Europe, but common in England. The colour of the young wood is silky white, and of the old, brownish white; the wood of the middle age is in¬ termediate in colour, and the strongest. It is used in furniture, pianofortes, and harps, and for the superior kinds of Tunbridge ware. Sycamore may be cut into very good screws, and is used for presses, dairy utensils, etc. Symmetry, in sculpture, etc., adap¬ tation of parts to each other; pro¬ portion ; harmony; agreement of one part with another. Sympiesometer, a barometrical instru¬ ment in which the atmospheric pressure is indicated by the ascent of a column of oil in a short glass tube against the elastic pressure of an enclosed volume of hydrogen gas. Its indications require cor¬ rection for the changes produced by temperature on the gas. The instrument is more compact, but also more complex, than the mer¬ curial barometer. Synagogue, a word which primarily j signified an assembly, but, like the word church, came at length to be applied to places in which any as¬ semblies, especially those for the worship of God, met, or were con¬ vened. Jewish synagogues were not only used for the purposes of divine worship, but also for courts of judicature. The present ordi¬ nary meaning of the term syna¬ gogue is a Jewish church. Syphering, in ship-building, lapping one edge of a plank over the edge of another for bulk-heads, making the edges of the planks and the sides of the bulk-head plain sur¬ faces. Syphon, a bent tube, having one leg shorter than the other. It acts from the pressure of the atmo¬ sphere being removed from the surface of a fluid, which enables it 476 TACHOMETER. TACK SYR to rise above its common level, and is used for 'the purpose of emptying liquors from casks, etc. Syringe, a small hand-pump : in its simplest form, it is provided with a piston and rod, but is destitute of valves, one simple aperture at the extremity serving for the ad¬ mission and ejection of fluid : those constructed with valves, however, are available, on a smaller scale, for all the purposes of an air-pump. Systyle, a term applied to a building in which the pillars are closely placed, but not quite so close as in the pycnostyle, the intercolum- niation being only two diameters, or four modules, of the columns. T Tabby, watered silk used by book¬ binders, the effect of waves pro¬ duced by pressure of the silk in a damp state after being sprinkled with water, a corruption of the French word tapis, whence tabbi- net, a more delicate kind of tabby, produced in calendering from en¬ graved rolls,the pressure from which gives the appearance of waves to the silk. Tabby, a mixture of lime, gravel, shells, stones, and water, in equal proportions, which when dry be¬ comes as hard and compact as stone, and is used on the southern shores of the Mediterranean as a substitute for bricks or stone in building, and, till recently, was also employed for the same purpose in Georgia, in the United States of America. Taberd (Saxon), a jerkin, a coat without sleeves ; also, a herald’s coat. Tabernacle, a movable fabric: among the Jews, the name of a portable temple which was constructed in the Wilderness : the term is also applied in Christian architecture to richly ornamented niches. Table, in architecture, a smooth simple member or ornament of various forms, but most usually in that of a long square. Table or Tablet mouldings, horizontal bands or mouldings, such as base- mouldings, strings, cornices, etc. Tables were in the Tudor age usu¬ ally described as ‘ bordes,’ and were not in any great variety : the sorts were but few, and little distin¬ ct guished by workmanship ; but the splendour of their coverings amply compensated for the rudeness and simplicity of the works so con¬ cealed. The most elaborate em¬ broidery, wrought on the finest grounds, velvets and satins fringed with gold and silver, Turkey car¬ pets, and the choicest tapestry, were used as table-covers. Table-cloths, carpets, which at earlier periods were almost the only co¬ verings for dining-tables and cup¬ boards ; naping was possessed by theTiigher orders only. In 1520, Thomas, Duke of Norfolk, be¬ queathed his naperie to Agnes his wife. Tabling, in ship-building, letting one piece of timber into another, in the same manner as the beams are put together. Tablinum, an apartment of a Roman house which was entered imme¬ diately from the atrium, and in which records were preserved in cases, and the hereditary statutes placed. Tachometer, an instrument for mea¬ suring the velocity of machines by means of the depression, occasioned in a column of fluid by centrifugal force, which causes the fluid in the cistern (with which the graduated column is connected) to sink in the centre more and more with every increase of velocity. Thus the graduated column falls on the scale as the velocity is augmented, and rises as the velocity is di¬ minished. Tack, in navigation, to change the 3 477 TACK TAPESTRY. course or turn about a ship during a contrary wind from the starboard to the larboard, etc. Tack, in navigation, a rope used to confine the clues of the main and fore courses forward, occasionally in a fixed position : it has a large wall-knot at one end. The word has also various other applications. Tacks, in navigation, the foremost lower corner of all fore and aft sails. Tacking, in navigation, signifies a manoeuvre by which a ship makes an oblique progression to windward in a zigzag direction, named also ‘ beating to windward.’ Tackle, in mining, the windlass, rope, and kibble. Taenia, the band or fillet surmounting the Doric epistylium. Taffrail, the carved work at the upper part of the stern of a vessel, the ends of which correspond with the quarter-pieces. Tail-water, the waste water dis¬ charged from the buckets of a water-wheel in motion. Talus, in architecture, the inclination or slope of a work, as the outside of a wall, where its thickness is diminished by degrees as it rises in height. Tambac, or Tombac, an alloy of copper and zinc, or a species of brass with an excess of zinc. When arsenic is added it is called white tombac. Tamp, the hole bored in the rock when charged for blasting ; hence to tamp is to fill up the hole bored for blasting. Tamping, in mining, the material, usually soft stone, placed upon the gunpowder to confine its force, which would otherwise pass up the hole ; also the process of placing the material. Tamping-iron, a tool used for beating down the earthy substance in the charge used for blasting. Tangent, in geometry, a right line perpendicularly raised on the ex¬ tremity of a radius, which touches 478 TAP a circle so that it would never cut it, although infinitely produced, or, in other words, it would never come within its circumference. Tank, that part of the tender of a loco¬ motive engine which contains the water: tanks vary in size, according to the power of the engine to which theyare attached, and are from about 500 to 1600 gallons in capacity. Tannin or Tannic Acid, the prin¬ ciple of astringency in vegetables, used in the process of tanning, and in photography. Tap, in mechanics, a hardened steel screw with a square head, so that it may be turned by a wrench : it is grooved from end to end, and is also slightly tapered : it is used for cutting an internal screw, as that of a nut, etc. Tap-wrench, the handle for turning a wrench. Taper, a gradual diminution in the size of a body, so as to form a wedge or cone. Taper-chain bridge, a suspension bridge invented by Mr. Dredge. Tapestry or Arras, described as ‘ hangings,’ enriched the walls of superior apartments from very early times: the most ancient tapestry now existing is preserved in the I church of Baveux, in Normandy, i and exhibits an entire series of the j circumstances attending William i the Conqueror’s descent inEngland. The arras was loosely hung in pro- j jecting frames, by tenter-hooks, ; across the walls, covering the whole j surface from the floor to the ceiling, j and was removable from one resi¬ dence to another. The most costly \ materials were employed in the fabrication of the best sort of hangings. The apartment of Henry VIII. at Calais, whither he was accompanied from Boulogne by Francis I. in 1520, was hung with cloth of gold, adorned with precious stones and pearls. Tappet-motion, the apparatus for working the steam-valve of a Cor¬ nish steam-engine, consisting of it TAR TEMPERATURE. TEM ' levers connected to the valves, moved at proper intervals by tap¬ pets or projecting pieces fixed on a rod connected to the beam. Tartan, a small coasting vessel of the Mediterranean, with one mast, a bowsprit, and a lateen sail. Taunt, a sea term, signifying too high or tall, as the mast of a ship. Teak-wood is a native of the moun¬ tainous parts of the Malabar coast, of Java, Ceylon, etc. It grows quickly, straight, and lofty. The wood is light and porous, and easily worked; but it is nevertheless strong and durable.- It is soon seasoned, and, being oily, does not injure iron, and shrinks but little in width. Its colour is light brown, and it is esteemed a most valuable timber in India for ship-building and house-carpentry. It has many localities. In twenty-five years the teak attains the size of 2 feet dia¬ meter, and is considered service¬ able timber, but it requires 100 l years to arrive at maturity. Tegula, a roofing tile : roofing tiles were made by the Greeks, like bricks, of baked clay. I Telamones, or Atlantes, statues of men, employed in columns or pilas¬ ters in classical architecture. Telegraph, a machine adapted for communicating intelligence rapidly at a considerable distance by means of various signals previously ar¬ ranged. Telescope, a large optical instrument for observing the celestial bodies, whereby several new phenomena have been discovered, and great improvements made in astronomy: by properly grinding and placing the lenses or glasses in a tube or pipe of various lengths, objects at a great distance are brought nearer to the eye, and much more distinct¬ ly seen than by the natural eye: there are various kinds of tele-! scopes, which are called by distinct names. Temperature. The temperature of the surrounding atmosphere exer¬ cises a powerful influence in the preservation or decomposition of all organic bodies exposed to it. Thus, while a high temperature hastens the decay of animal and vegetable matter, this is completely arrested at or near the freezing- point of water. Hence, by artificial means, these substances may be preserved for a length of time. A citizen of the United States has thus accomplished the means of preserving meats, fruits, etc. A large apartment is built under the ground, the sides of which are lined with a double wall containing saw-dust: over the ceiling is a room filled with ice, which, gradually melting, filters through the saw¬ dust, and keeps the temperature of the underground apartment alw T ays at 34° Fahr., or two degrees above the freezing-point. In this apart¬ ment, lemons, oranges, apples, strawberries, flow'ers, etc., are pre¬ served with complete freshness for any length of time that may be re¬ quired. Temperature of different Thermome¬ ters. A thermometer is an instru¬ ment for measuring the tempera¬ ture of bodies, or the degree of intensity of their sensible heat. In Europe there are three different kinds of thermometers : 1. Fahren¬ heit’s, which is used chiefly in Great Britain, Holland, and North Ame¬ rica, the freezing-point on which is at 32?, and the boiling-point 212°. 2. Reaumur’s,which was that chief¬ ly used in France before the Revo¬ lution, and now generally used in Spain and in some other Conti¬ nental States: the freezing-point, or zero, is 0°,and the boiling-point 80"’. 3. The Celsius, or Centigrade thermometer, now almost univer¬ sally used throughout France, and in the northern and middle king¬ doms of Europe: the zero or freez¬ ing-point is 0°, and boiling-point 100°. Hence, in order to reduce degrees of temperature of the cen- tigrade thermometer, and of that of 479 TEM TEMPERATURE. TEM Reaumur, to degreesof Fahrenheit’s scale, and conversely,—Rule I. Multiply the centigrade degrees hy 9, and divide the product by 5 ; or multiply the degrees of Reaumur by 9, and divide the product by 4 ; then add 32 to the quotient in either case, and the sum is the de¬ grees of temperature on Fahren¬ heit’s scale. Rule II. From the number of degrees on Fahrenheit’s scale subtract 32, multiply the re¬ mainder by 5 for centigrade de¬ grees, or by 5 for those of Reau¬ mur’s scale, and the product in either case, being divided by 9, will give the temperature re¬ quired. In all inquiries into the effects of heat, it is necessary to attend to the following rules respecting the application of the term Temper¬ ature :— lstly. If a body subject to no pressure, or to a constant pressure, have at two different times the same bulk, it is said on both occa¬ sions to have the same tempera¬ ture. 2ndly. Two bodies are said to have the same temperature, if, be¬ ing kept in contact, the tempera¬ ture of either remains unaltered by the action of the other. 3rdly. When bodies of different temperatures are in contact, the temperature of the hotter body decreases, and that of the colder increases, till they become equal. 4thly. If the bodies be equal in mass or in weight, and of the same substance, the increase of tempe¬ rature in one will be equal to its decrease in the other. Hence it will he seen that dif¬ ferences of temperature are mea¬ surable and comparable with each other, quite independently of any change of bulk; that is, without using the latter as a measure of temperature, but only as a test by which change of temperature is de¬ tected. In this way it has been disco- covered that the same increment (not equal increments, as from 40° to 50°, and from 50° to G0°) of temperature causes all masses of the same substance to expand in the same ratio to their whole for¬ mer bulk; but this is by no means the case with different substances, as is obvious by looking at a com¬ mon thermometer, an instrument for measuring changes in the bulk of a mass of liquid contained in a glass vessel, of such a form that changes, very small compared with the whole bulk of the liquid, may cause its surface to rise and fall through a considerable space. But this could not be done if the glass and the measuring scale, in undergoing the same changes of temperature as the liquid, expe¬ rienced also the same change of bulk; for, if such were the case, # the liquid surface would always re¬ main opposite the same degree on ! the scale. The value of this sim- j pie instrument therefore depends on the fact that liquids are more expansible than solids. But it will further be seen that i the ratio of the change of bulk to the wdiole bulk is different for every different substance, when the change of temperature is the same in all. It is necessary, however, to guard against a very common error respecting the relation be¬ tween temperatures and the num¬ bers by which they are represented; ; namely, the degrees of the ther¬ mometer. Although the differences of tem¬ peratures are known and compara¬ ble quantities, yet their ratios are not so : they can be compared by addition and subtraction, but not < by multiplication or division. We cannot say, “ This temperature is so many times that,” because we do not know the real zero of tem¬ perature ; that is, we do not know whatis the smallest bulk into which a given body is capable of being condensed by cold. We cannot, 480 TEM TEMPERING. therefore, say, “ This body exceeds its minimum bulk by twice as much as that body exceeds its minimum bulk j” or, in other words, “ This body is twice as hot as thatfor although the temperature of one body may be 80° and that of an¬ other 40°, these numbers are only reckoned from an arbitrary zero or starting-point, adopted because the real zero is unknown. But al¬ though we cannot say that A has twice the temperatureof B, we can say that the temperature of A ex¬ ceeds that of B by twice as much as the temperature of C exceeds that of D. The first question, then, regard¬ ing the relation of expansion to temperation, is—“ Do equal dif¬ ferences of temperature cause the bulk of a body to vary by equal differences ?” This question had to be settled before it could be known whether the common ther¬ mometer (the scale of which is divided into equal parts) measured differences of temperature cor¬ rectly. For this purpose, Dr. Brooke Taylor heated two equal weights of water, one to 200° and the other to 100°, and on mingling them together, he found them to indicate exactly 150^; thereby showing that equal differences of temperature cause equal differences in the expansion of mercury; or rather in the excess of its expansion over that of glass, which is clearly all that the thermometer can mea¬ sure. More accurate experiments, j however, have shown that this rule does not exactly apply to any solid or liquid, but only to gases. When equal masses of the same liquid, at different temperatu«;s, are mixed, their combined bulk becomes a very little diminished. Liquids, therefore, instead of expanding by equal increments of space for equal increments of temperature, expand faster as the temperature increases equably; and it appears that the correctness of the mercurial ther- TEM mometer observed by Dr. Brooke Taylor was the result of a fortunate coincidence, by which the expan¬ sion of the glass, which is very small compared w'ith that of the mercury, exactly compensated the increasing rate of the latter. This however, would not be the case with thermometers constructed with other liquids, for their rates of expansion increase more rapidly than that of mercury. Hence spirit thermometers cannot be de¬ pended on for temperatures above the atmospheric range (or above 100 °). Tempering, in metallurgy, the pre¬ paring of steel or iron, so as to render them more compact, hard, and firm, or the reverse, more soft and pliant. Tempering of steel. Nearly every kind of steel requires a particular degree of heat to impart to it the greatest hardness of which it is susceptible. If heated, and suddenly cooled be¬ low that degree, it becomes as soft as iron: if heated beyond that de¬ gree, it becomes very hard, though brittle ; and its brittleness is an in¬ dication of the degree of its heat, when cooled off. These are the reasons why, in hardening steel, it is generally overheated, and then tempered. To hit the exact heat required is a matter of extreme delicacy. The hardening of steel may be perfectly understood by studying its nature. In endeavouring to arrive at the temperature best adapted to a particular case,—a case, for instance, in which a strange kind of steel has to be dealt with, — a practical test, namely drawing the bar into a tapered point or chisel, is applied. This wedge-shaped chisel will, of course be more warm towards the point than at the thick part; and it is evident that this part will, when cooled in the same cold medium, be harder than the thick part. By breaking, and continuing to break 481 TEM TEMPLE. TEM off, the point, the difference of grain will show the different tem¬ peratures which have been applied. The finest and closest grained is considered the best. In hardening such steel, it is heated with a due relation to the degree of the test-heat. Though this manipu¬ lation is very imperfect, careful and intelligent workmen are generally quite successful in arriving at a knowledge of w'hat degree is fa¬ vourable. The degree of hardness depends, in some measure, upon the heat of the steel, but mainly upon the difference between the heat of the steel and that of the water or medium in which it is cooled. The coldest water will make the hardest steel. Mercury is better adapted to harden steel than water; so is water acidu¬ lated with any kind of acid, or con¬ taining any kind of salt in solution. The process of hardening is per¬ formed with due relation to the quality of the steel and the pur¬ poses for which it is designed. In most instances, the hardening is effected in water or brine. Saw- blades are thus hardened, after being heated in melted lead ; and sabres are heated in a choked fire of charcoal, andthen swung rapidly through the air. Mint stamps are hardened in oil or metallic compo¬ sitions. The common method of procedure in hardening is this: The steel is overheated, cooled in cold water, and then annealed or tempered by being so far re-heated that oil and tallow will burn on its surface; or the surface is ground and polished, and the steel re¬ heated until it assumes a certain colour. The gradations of colour consecutively follow : alightstraw- yellow, violet, blue, and finally grey or black, when the steel again be¬ comes as soft as though it had never been hardened. Templa, certain timbers introduced in the roofs of temples; they were placed upon the canterii, or prin- cipal rafters, extending the whole length of the temple from one fas- tigium to the other, corresponding in situation and use w'ith the com¬ mon purlins. Temple , a building set apart for the services of religious worship, espe¬ cially the Jewish, and those which were dedicated to the heathen deities: the name is not unfre- quently applied to Christian sanc¬ tuaries, for example, the Temple church, London. The first Jewish temple, built by Solomon, was erected at vast expense; the gold and silver only, which was pro¬ vided for the purpose, amounting, it is said, to an almost incredible sum. It was built much in the same form as the Tabernacle, only every way of larger dimensions. | It was surrounded, except the front or east end, with three stories of | chambers, each 5 cubits square, j which reached to half the height of the temple, and the front was graced with a magnificent portico, which rose to the height of 120 J cubits, so that the shape of the ! whole was notunlikesome churches which have a lofty tower in the ; front and alow aisle running along each side of the building. This j temple was plundered by Nebu¬ chadnezzar, King of Babylon, and the building itself destroyed, ac¬ cording to Josephus, after it had stood between 400 and 500 years. The second temple, erected after the Jew's’ return from Babylon, stood for 500 years, when Herod rebuilt it in a style of great mag¬ nificence. Tacitus, the Roman his¬ torian, calls it a temple of immense opulence. This magnificent temple was at length destroyed by the Romans in the same month and on the same day of the month as Solomon’s temple was destroyed by the Babylonians. Of the temples of classic history, the most cele¬ brated are those of Greece, con¬ sisting of the Parthenon, built un¬ der Pericles, the Erechtheum, and L TEM others noticed in Stuart’s ‘ Anti¬ quities,’ and in the works of the Dilettanti Society, of Cockerell, Donaldson, etc.: of Rome, the chief temples were, the Capitol, the Pantheon (built by Agrippa), the temple of Apollo, the temple of Janus, and others interestingly described by Degodetz, and also by Taylor and Cresy. Temple of Solomon had no arches. In the Tabernacle, the Holy of Holies, where the ark was placed, was a cube of 15 feet. (Exod. xxvi.) The Holy Place, where the golden lamps and the table of shew-bread stood, was a double cube of 15 feet. In the Temple, the Holy of Holies was a cube of 30 feet, the Holy Place a double cube of 30 feet. The whole structure was 90 feet long and 45 feet high. The front over the porch seems to have been adorned with a towering edifice of j some kind or other, of an elevation of 180 feet. The Brazen. Pillars, or two co¬ lumns standing before the gate of the Temple, seem to have been 6 feet in diameter and 52 feet 6 in. high, or nearly 9 diameters (com¬ pare 1 Kings vii. 15, with 2 Chron. iii. 15, although there is in the first passage a proportion of height mentioned which causes some con¬ fusion). The capitals were 6 feet in diameter exclusive of their pro¬ jecting ornaments, and 7 \ feet high, or one diameter and a quarter. The portico of the Temple was 30 feet long and 15 feet wide, in open height 45 feet. The Cherubim on each side of the ark were 15 feet high ; their wings, which w r ere extended to meet each other, were feet, and the Cherubim and Palm-trees on the wall, which were of carved work covered with gold, seem to have been of just the same proportion. The greatest part of the cloisters are affirmed to have been construc¬ ted of beams of wood laid upon TEN massy pillars. Their outside wall was of stone, 12 feet thick. The roof was probably flat, ac¬ cording to the general usage of building in Eastern countries, as we know that the Romans sta¬ tioned a guard of soldiers on the roof of the cloisters to preserve order at public festivals. Yet as the seditious Jews are said to have set fire to the north¬ west cloister in order to prevent the Romans fromtaking the Temple through the castle of Antonia; and afterwards we are told that they filled that part of the western cloister which was between the beams and the roof with dry ma¬ terials and with bitumen and pitch, and setting it on fire the flame burst out on every side. There appears a probability that the roof was not flat, at least it is evident that the interior ceiling was not the floor of the external covering. Templet, a gauge cut out of a thin piece of metal to the form of the work to be executed. Templum (Latin), a temple. Tem¬ ples appear to have existed in Greece from the earliest times; they were separated from the pro¬ fane land around them, and the en¬ trances were much decorated as architecture advanced. Tenacity, that quality of bodies by which they resist tension or tear¬ ing asunder. Tender, the carriage which is attached to a locomotive engine, and con¬ tains the supply of water and coke. Tenon, in carpentry, the square end of a piece of wood or metal dimin¬ ished to one-third of its thickness to be received into a hole in ano¬ ther piece, called the mortise, for the jointing or fastening of the two together. Tension, a force pulling or stretching a body, as a rod. Animals sustain and move themselves by the ten¬ sion of their muscles and nerves. A chord, or string, gives an acuter or deeper sound as it is in a greater TEMPLE OF SOLOMON. 483 TEN TESSERA. or less degree of tension, that is, more or less stretched or tightened. Tension-rod, an iron rod applied to strengthen timber or metal framing, roofs, etc., by its tensile resistance. Term, a piece of carved work placed under each end of the taffrail of a ship, at the side timbers of the stern, and extended down as low as the foot-rail of the balcony. Terra Cotta, in the arts, baked earth, bricks, tiles, etc. Terra di Sienna, or Raw Sienna Earth, a ferruginous native pig¬ ment, which appears to be an iron ore, and which may be con¬ sidered as a crude natural yellow lake, firm in substance, of a glossy fracture, and very absorbent. It is in many respects a valuable pig¬ ment, of rather an impure yellow colour, but bas more body and transparency than the ochres ; and being little liable to change by the action of either light, time, or im¬ pure air, it may be safely used, ac¬ cording to its powers, either in oil or water, and in all the modes of practice. By burning, it becomes deeper orange and more trans¬ parent and drying. Terre-verte, an ochre of a bluish- green colour ; in substance mode¬ rately hard, and smooth in tex¬ ture. It is variously a bluish or grey coaly clay, combined with yellow oxide of iron, or yellow ochre. Although not a bright, it is a very durable pigment, being unaffected by strong light and im¬ pure air, and combining with other colours without injury. It has not much body, is semi-transparent, and dries well in oil. There are varieties of this pigment; but the green earths which have copper for their colouring matter are, though ge¬ nerally of brighter colours, inferior in their other qualities, and are not true terre-vertes. Tessellated, in the arts, variegated by squares ; exemplified in the beau¬ tiful pavements of the ancients. Tessera, small cubical pieces of brick, THE stone, or composition, forming part [ of an ancient Roman mosaic or tessellated pavement. 7WaeeoMS, consisting of shells ; made j of baked earth, or of tiles or bricks. Tetragon, a quadrangle, or a figure having four angles. Tetrahedron, in geometry, one of the five regular bodies of solids com¬ prehended under four equilateral and equal triangles. It may be conceived as a triangular pyramid | of four equal faces. Tetrants, the four equal parts into which the area of a circle is divi- ] ded by two diameters drawn at 1 right angles to each other. Tetrastyle, a portico, etc., consisting j of four columns. A cavaedium was called tetrastyle when the beams of the compluvium were supported by columns placed over against the I four angles of a court. Thatch, straw or reeds employed for covering the roofs of buildings; I particularly used for cottages. Thoughts or Thwarts, in navigation, the benches or seats in a boat. Theatres, edifices of various but prin¬ cipally of large dimensions, for dramatic exhibitions. Theatrum, a theatre. The Athenians, . before the time of dischylus, had only a wooden scaffolding on which their dramas were performed. It was merely erected for the time of the Dionvsiac festival, and was afterwards pulled down. Theodolite, in surveying, a mathe¬ matical instrument for measuring heights and distances. (See Hea¬ ther’s work on Instruments.) Theorem, a term used in mathema¬ tics to signify a proposition which \ states a conclusion and requires its demonstration; as distinguished from a Problem, which leaves the conclusion to be discovered. Theory, a doctrine which terminates in the sole speculation or consi¬ deration of its object, without any view to the practice or application of it. To be learned in an art, the theory is sufficient; to be mas- 484 ■ THE THEORY (MATHEMATICAL) EXPLAINED. THE ter of it, both the theory and prac¬ tice are requisite. Machines often promise very well in theory, but fail in practice. A remarkable circum¬ stance may be instanced of a gen¬ tleman of British North America selling his estate and leaving his home to give practical effect to a theory he had, as he considered, beautifully worked out in figures, for an important improvement in steam-machinery. His theory', how¬ ever, wholly failed on its first ap¬ plication in practice. Theory, mathematical, the algebraic elucidation of the principles of any physical system, where assumptions are made, in the absence of positive data: the calculated results are expressed in formulae, which are easily convertible into arithmetical rules. Among others, the ‘ Theory of the Steam Engine,’ by the Count de Pambour, has been found to be most useful for practice; and the following is an explanation of his mathematical investigation, de¬ signed for persons not familiar with the algebraic signs, and intended to render clear and easy the use of theformulae contained in the above- mentioned work, and which may be said to have reference to all ma¬ thematical works. Among persons engaged in the construction or working of steam- engines, there is a great number to whom the algebraic terms are little familiar, and who usually give up the readingof a hookas soon as they perceive that it steps beyond the simple notions 1 + J (2736+/); this signifies that the required value of a r will be obtained by perform¬ ing the following arithmetical ope¬ rations : — Add 1 to the number represented by the letter 8, and multiply the sum by the number v. Then divide the number S by the product thus obtained; multi¬ ply the quotient of this division by the number 4140750 ; and write 488 THE apart this first partial result, which represents the first term of the formula. Add again to unity the number 8, and by that sum divide the number a. Similarly add to the number 2736 the number f and multiply the sum by the last found quotient; and set apart this partial result, which represents the second term of the formula. Finally, from the first partial re¬ sult subtract the second, and the difference will be the quantity a r sought. Performing these different ope¬ rations with the values of S, a, 8, r, and/", given above, and supposing the case wherein the letter v has the value » = 300, you find that the quantity a r will have for its definitive value a r — 4146. III. If we have the formula s =ISiS ){ 6 ' 6075 + - 002415 [ and pure platina 2T 5 ooi or lf * datum is taken of 1 for water, gold will be 20, and refined platinum 22. Water is incompressible, as expe¬ riment proves. It has been put into a gold globe, and great power applied in vain to press it into a smaller compass; it passed off bv oozing or sweating through the pores of gold. It will rise in some cases above its own level. In a small degree, by capillary attrac¬ tion. If a piece of dry loaf-sugar or sponge is put into a shallow vessel of water, and have part of it unimmerged, the fluid will be seen to ascend above its level. Water will also ascend to the height of 32 or 33 feet above its level in a vacuum, as in pumps, by the pressure of the atmosphere, which varies more oi less according to its density, that is, calculating on the pressure of the atmosphere, at the height of 15 miles. The pressure of water on the base of the vessel in which it is contained is as the base and perpendicular altitude, whatever be the figure of the vessel that con¬ tains" it. A body immersed in water loses as much weight as an equal hulk of the water weighs, and the water gains the same weight. Thus, if the body be of equal density with the water, it loses all its weight, and so requires j no force but the water to sustain it: if it be heavier, its weight in the water will be only the differ ence between its own weight and j the weight of the same bulk of water, and it requires a force to j sustain it just equal to that differ- | ence; hut if it be lighter, it re¬ quires a force equal to the same difference of weight to keep it from rising up in the fluid. Water of great rivers may cer¬ tainly he deemed the most pure and wholesome for all culinary and domestic concerns, independ¬ ent of its superior fertilizing powers when used for the purpose of agri¬ culture or the growth of plants; and when thrown into reservoirs, and cleared of its sediment, it be¬ comes clear and equally transparent with the brightest water proceed¬ ing from the hardest rock; for, ; previous to its being thus deposited, j while swiftly gliding within its hanks, it deposits large portions of j its bituminous, calcareous, argil- j laceous, and chalybeate qualities, j Water is a conductor of atmo- ; spheric air, as well as sound, j In Ralph Dodd’s ‘ Civil Engineer | an accident is mentioned, by which j. one of his workmen was buried, j j by the falling of 40 feet of a shaft, if the bottom of which approached , to a sand highly charged with . water. He remained from Friday evening till Tuesday morning. The ,i workmen were this considerable time before they came to him, conversing together and excavating over his head, which considerably increased his hope of being re- j leased from his horrid captivity: for he became aware of their endeavours for his release as soon , as the workmen had entered the sandy stratum, through which the water filtered downward,—a strong i evidence of its conveying sound^ 540 WAT WATER-COLOUR PAINTING. WAT as well as atmospheric air, or, doubtless, he could not have ex¬ isted. Day-springs, either lying near the surface of the earth, or finding fresh passages thither, break: forth into open air on their own account; while those of a deeper nature are sunk down so low as to require hydraulic machinery to bring them up again. Next, they are called top-springs, inasmuch as they ap¬ pear either above the rock which severs the soil from the mine, or underneath it. Top-springs differ from deep or other springs, in that they stagnate between the super¬ ficies of the earth and the surface of the parts confining them, till they are opened by the miner; and those springs that can be let off by drifts, headings, soughs, and trenches, are distinguished from those from a great depth, the drain¬ ing of which by such means is alto¬ gether impracticable or absolutely impossible. In the search after the original source of those cur¬ rents of water which issue out of the earth, and are commonly called day-springs, the first con¬ sideration that arises is, that their natural course, as consisting in motion, is merely local, and caused by the propension of their own weight, still drawing them down¬ ward, towards the centre of the earth: their course must always be upon a constant descent from a higher situation to a lower, and so must proceed originally from rain, distilled from the clouds. And if it happen, that at their emersion out of the earth, their spring rises upwards, it is caused by the curvity of their passage, that (siphon-like) points the way ; while the preponderance of the water contained in its other arm, descending from a greater height, forces it to rise contrary to its natural inclination. The specific gravity of rain-water is 1000; weight of a cubic foot 2 A 62J lbs. ; weight of a column, one inch square and a foot in height, 0A34 lbs.; of an ale gallon 10 2 lbs.: expands of its bulk in freezing, and -gfg-g for every degree of heat: boils at 212° under the ordinary pressure of the atmo¬ sphere : maximum density 39 0- 38 of Fahr. The specific gravity of sea-water is 11-0271. Water-colour painting is the art of making a picture with colours ground up with various kinds of aqueous gums or sizes, then called transparent colours. These draw¬ ings are executed on various kinds of paper, and are generally termed tinted drawings. The following are the most permanent colours, and therefore most valuable to the water-colour painter : blues —ul¬ tramarine, French ultramarine, co¬ balt, indigo, and smalt: reds —-In¬ dian red, light red, Venetian red, scarlet, vermilion, carmine, pink madder, rose madder, purple lake, and red orpiment: yellows —cad¬ mium yellow, gamboge, yellow ochre, Indian yellow, Mars yellow, lemon yellow, Roman ochre, brown ochre, Mars orange, raw sienna, Italian pink, gallstone, and king’s yellow : purples —purple madder, Indian purple, and burnt carmine: browns —burnt sienna, brown pink, burnt umber, Vandyke brown, se¬ pia, Mars brown, Cologne earth, bistre, and madder brown : greens —emerald green, olive green, and green oxide of chromium: blacks —ivory black, blue black, neutral tint, and British ink : whites —ox¬ ide of zinc or Chinese white, and sulphate of barytes or constant white. Water-crane, an apparatus for sup¬ plying water from an elevated tank to thetender of a loeomotiveengine. Watering the streets of Paris (the contract for). The contractor for this service receives 105,000 francs per annum, or £4200 sterling. It lasts from March 15th to Octo¬ ber 15th. 541 WAT WATER SUPPLY. WAT He is bound to hold at the dis¬ posal of the engineers who are charged with the direction of the roads, twenty-five carts during the first month of the season; during the second, the number is fixed at fifty-five ; during the remainder at ninety, with fifteen others in re¬ serve. These carts can only he used for the service of the town ; and they are repainted every year. Thev contain 1 metre cube, or 1 ton 'each, and are drawn by one horse. They have a double dis- charge hose, at the front and at the hack. At half-play they water 1000 metres superficial. At full play they water 700 metres super¬ ficial. In the first case, they are emptied in 10 minutes; in the second, in 6 minutes. Each cart costs 800 francs, or £32 ; of which 200 francs, or £8, are for the ma¬ chinery necessary for the distribu¬ tion of the water. , The Avenue de Neuilly in the Champs Elysees forms a special service, on account of the immense number of carriages which traverse it. The total surface is -32,000 metres superficial, or nearly 8 acres English (7-976 a). The cost per day in the summer months is as follows 2 water-carts, horse and driver included, each at 11-10 f. = • • • 22-20 84-00“ cube water (a metre cube = 1 ton) at 0137 f. = • • .• 11-50 Turncock (portion of his time) .... Total 35-70 or 0-001116 f. per metre super¬ ficial. It has been found that the streets of Paris require to be watered 135 days on the average ; the numbers are between 107 in the wettest sea¬ son, and 147 in the driest. On the above average of 135,100 days require st double watering, fbe quantity consumed is about 1 litre (1-760773 pints English) per metre superficial; li litre, when the roads are so very dry as to require a more abundant watering; and 1-60 litre (or 2-82 pints English) in the Avenue de Neuilly. The water-columns are spaced so as to avoid any useless movements of the carts; in fact, in such a manner as to allow of their being emptied be¬ tween one column and the other. The usual distance is 500 metres (about 550 yards). Water-sail, in navigation, a small sail spread occasionally under the lower studding-sail or driving- boom, during a fair wind and smooth sea. Water-spout, a strongly agitated mass of air, which moves over the sur¬ face of the earth, and revolves on an axis, of which one extremity is on the earth and the other in a cloud. From this cloud a continu¬ ation proceeds downwards, which forms the upper portion of the wa¬ ter-spout; while the lower portion, besides air, consists sometimes of water, sometimes of solid portions, according as the water-spout passes over land or over water. Some have separated water-spouts over the land and over the water from each other; but this creates confu¬ sion, for water-spouts have been observed which were formed over water, and advance over land; and vice versa, we have accounts of water-spouts which were formed over land, and afterwards sus¬ pended over the surface of water. Water supply for towns. A plentiful supply of water fitted for drinking, culinary, and detergent purposes, is so essentially an article of every¬ day use, that in all ages, wher¬ ever a quantity of human beings have been congregated together, contrivances have necessarily been resorted to, to procure a supply: in some situations wells are sunk to a considerable depth, from which water is lifted by means of buckets, pumps, or like contriv ances; in 542 WAT WATER SUPPLY FOR TOWNS. others, the rain-waterfalling on the roofs of houses is caught and hus¬ banded in suitable receptacles, or, —as was much practised in ancient times, where large populations ex¬ isted,—rivers are diverted for their use from their natural channels, and conducted over valleys and through mountains in artificial courses having a small but con¬ tinuous decline. Much has been written and said of the plentiful supply of water brought into ancient Rome and towns in Italy, Spain, and other places, by means of aqueducts; but the streams supplying these aqueducts would yield but little water in the dry summer and autumn weather, as is proved from the number of sources from which water was frequently brought to a town. Ancient Rome, according to some writers, was supplied from no less than twenty aqueducts, all deriving their water from different sources. These aqueducts were built at separate times, and they were doubtless made to supply a pressing want; for although in wet and moderate seasons, probably one-third this number would have yielded a supply adequate to the demand, it is much to be doubted if this was the case in seasons of drought; especially as the ancients made no provisions by means of impounding reservoirs to store a supply from wet to dry seasons. In ancient times, water was brought to a town from rivers or springs more elevated than the town itself, and was distributed through fountains to the inhabitants, who fetched it in vessels to their houses. In modern times, excessive floods are frequently stored in large re¬ servoirs, to yield a supply to our towns in seasons of drought; or water from a neighbouring river, or from deep wells sunk in a sub¬ terranean reservoir, or water-bear¬ ing stratum situated below the level of a town, is frequently lifted WAT by means of pumps, worked by steam or water power, through a line of cast-iron pipes into a reser¬ voir of sufficient altitude to admit of its being conducted from thence through other pipes to the highest bouse in a town ; and it is no un¬ common thing at the present time to lift water from 200 to 300 feet in elevation for this purpose. But the greatest improvement lately made for supplying towns with water consists in the arrange¬ ments for conveying it, when raised to a sufficient altitude, in cast iron or lead pipes, into the house of every inhabitant, even to the upper story, so that this necessary article can always be secured by the turning of a cock : it is also dis¬ tributed in the same manner for watering roads, and for use in case of fire; and it is principally in the excellent system of distribution, which perfection in the art of making the pipes has induced, that renders modern water-works supe¬ rior to those of ancient times. It is of the utmost importance to every house to be supplied plen¬ tifully with wholesome soft-water, and there are now few places in which this cannot be accomplished at a cheap rate. The modern cost of supplying water to a large town may now be taken at a low estimate per head of the population supplied, according to the facilities or diffi¬ culties that exist for procuring and distributing the supply: as a gene¬ ral rule, river-water, when unpol¬ luted with the drainage of a town, or the rain-water flowing down the sides of steep hills of a retentive character, when properly filtered, is superior in quality, and better adapted for most domestic uses than the brightest spring water, owing to its freedom from saline matter, which is usually denomi¬ nated softness. All rain and surface water should, however, be carefully filtered be- 543 2 a 2 WAT WATER-WHEEL. WAT fore it is applied for domestic uses, not only to free it from earthy me¬ chanical impurities, but to rid it of organic matter, which in summer¬ time and warm weather is always mixed with such water in a greater or less degree, and the presence of which renders it unwholesome for drinking or culinary uses. It is principally owing to its freedom from organic matter that spring- water, though usually hard, is pre¬ ferred to river-water as a beverage. London is supplied with water chiefly by eight companies, the New River, East London, West Middlesex, Chelsea, Grand Junc¬ tion, Lambeth,Vauxhall, and South¬ wark. Water-ways, in ship-building, the planks of the deck which are close to the timbers. Water-wlieel, a wheel turned on its axis by the weight of water falling upon its circumference, and thus adapted as a machine for deriving power wherever a fall of water can be commanded. For this purpose the wheel is erected in a vertical position upon a horizontal shaft or axis, and the periphery of the wheel is so formed that the great¬ est possible effect shall be received from the weight or gravity of the falling water. To obtain this ef¬ fect, the rim of the wheel is pro¬ vided withsmalltrcughs or buckets in which the water is received, and its weight made active in carrying down that part of the periphery on which the loaded buckets are situ¬ ated. As they approach the lowest position, they become emptied, and are thus prepared to be carried up¬ ward during the revolution of the wheel, while the descending buck¬ ets are successively receiving their supply from the fall of water. Water-wheels are commonly dis¬ tinguished according to the height of the fall in comparison with the diameter of the wheel, and the po¬ sition at which the water acts upon the buckets. Thus if the depth of fall equals the diameter of the wheel, (besides allowing a little de¬ clivity below the wheel, for the ready escape of the back-water,) so that the water falls on the highest point of its periphery, the wheel is said to be an ‘ overshot ’ water¬ wheel. If the depth of fall is less, so that the water falls upon the wheel, only a little above the level of its centre, the wheel is called a “breast” wheel. And if the depth of fall is so little that the water acts by impulse only against the lower parts of the wheel, it is called an ‘undershot’ water-wheel. Water¬ wheels are now made in the most improved manner of iron, the arms being of wrought iron, the centres of cast iron, and the buckets of plate iron. A water-wheel thus constructed consists of a centre boss, and shaft, arms, buckets, and shrouding, the latter being the term applied to the rims of the wheel, between which the buckets are enclosed. In order to derive the greatest working effect from a given fall of water, the principal object is to shape the buckets so that they shall retain the water during the longest possible period. One great difficulty experienced in seeking this object has been the opposition exerted by the air to the admission of the water into the buckets; and, to counteract this evil, several methods have been devised. The only efficient remedy yet introduced is that invented by Mr. Fairbairn, and which he de¬ nominates the ‘ Ventilating Water- wheel,’ the general object of which is to prevent the condensation of the air, and to permit its escape during the filling of the bucket with water, as also its re-admission during the discharge of the water into the lower mill-race. Several wheels erected and fitted upon this principle have proved entirely suc¬ cessful in realizing a maximum use¬ ful effect from a given fall of water. All these wheels are formed with 544 WAT WATER-WHEEL. WAT wrought iron arms radiating from cast-iron centres to the periphery, and so disposed that the entire structure is in a state of tension, and the motion of the wheel being communicated from internal toothed wheels fixed to the shroud¬ ing. As applied to common breast- wheels adapted for falls not ex¬ ceeding 18 or 20 feet, these venti¬ lating buckets effect so great an improvement, that if the wheel is plunged in hack-water to the depth of 5 or 6 feet, its uniform speed is not impended. In these wheels the sole of the buckets is close, and the tail end of them being turned up at a distance of 2 inches from the back of the sole-plate, and running parallel with it, terminate within about 2 inches of the bend of the bucket, immediately above it. The water in entering the bucket drives the air out through the aperture into the space behind, and thence into the bucket above, and so on in succession. The converse oc¬ curs when the buckets are emptied, as the air is enabled to enter as fast as the wheel arrives at such a position as to permit the water to escape. (For a more copious de¬ scription, see Water-wheels with ventilating buckets, by Fairbairn.) There are many cases in which it is of importance to know the proportion of power necessary to give different degrees of velocity to a mill; but as the construction of mills and the purposes they serve are various, it is perhaps im¬ possible to find any law of univer¬ sal application. Mr. Banks, in his ‘ Treatise on Mills,’ has drawn a conclusion which he appears to consider invariable, namely, that “ when a wheel acts by gravity, its velocity will be as the cube root of the quantity of water it re¬ ceives.” But supposing a wheel to raise water by means of cranks and pumps on Mr. Banks’s principle, Buchanan thought it might easily be demonstrated, that by reducing the velocity of the wheel to a cer¬ tain degree, the wheel would raise more water than would be neces¬ sary to move it at that velocity,-— a thing evidently impossible. In this view T it would seem that there is no actual case in which Mr. Banks’s conclusions will hold true. But, however they may ap¬ ply to other mills, the experiments of Buchanan seem to prove at least that they do not apply to cotton-mills. On the ground of some experiments made at differ¬ ent times, and with all the atten¬ tion possible, did he presume to call in question an authority for which the highest respect is enter¬ tained. In January, 1796, he measured the quantity of water the Rothesay old cotton-mill required; first, when going at its common velocity, and secondly, when going at half that velocity. The result was, that the last required just half the quantity of water which the first did. It is to be observed, that in these experiments the quantities of water were calculated from the heads of water and apertures of the sluices. From these experiments he in¬ ferred, “ that the quantity of water necessary to be employed in giving different degrees of velocity to a cotton-mill must be nearly as that velocity.” He was satisfied with this expe¬ riment, and the inference drawn from it, till some gentlemen well acquainted with the theory and practice of mechanics expressed their doubts on the subject. He had then recourse to another ex¬ periment, which he considered less liable to error than the former. The water which drives the old cotton-mill falls a little below it into a perpendicular-sided pond, which serves as a dam for a corn- mill at some distance below it. To ascertain, therefore, the propor- 545 WAT WATER-WHEEL. WAT tional quantities of water used by the old mill, nothing more was necessary than to measure the time the water took to rise to a certain height in that pond; and accord¬ ingly, on the 1st of May, 1798, he made the experiments noted in the following Table:— Number of experi¬ ments . 12 3 4 Revolutions of one of the upright shafts per minute ... 46 46 24 23 Rise of water in the pond in inches . . 5 5 5 5 Time in minutes and seconds .... 6'58 6’57 14‘45 15'0 The first and second experiments were made with the mill at its common velocity; the third and fourth at nearly half that velocity. The time which the mill re¬ quired to use the same quantity of water in these experiments may be taken, in round numbers, as follows :—the proper velocity at 7 minutes, and half that velocity at 15 minutes. The result of these experiments approaches very nearly to that of 1796. The difference may be ac¬ counted for by the small degree of leakage which must have taken place at the sluices on the lower end of the pond; and the time being greater in the third and fourth experiments, the leakage would of course be greater. Smeaton and others have proved in a very satisfactory manner, that “ the mechanical power that must of necessity be employed in giving different degrees of velocity to the same body, must be as the square of that velocity.” But it appeared to Buchanan that the result of the above experiments may be easily reconciled to this proposition, by considering what Smeaton says immediately afterwards:—“If the converse of this proposition did not hold true, viz. that if a body in motion, in being stopped, would not produce a mechanical effect equal or proportional to the 546 square of its velocity, or to the mechanical power employed in producing it, the effect would not correspond with its producing cause.” It is to be observed, that Smeaton’s experiments were made on the velocity of heavy bodies, free from friction and other causes of resistance ; but in mills there is not only friction, but ob¬ stacles, to be removed: and ex¬ periments made on friction have proved that the friction of many kinds of bodies increases in direct proportion to their velocity. But the velocity of a cotton-mill at work may be considered as a me¬ chanical effect; and, if so, must correspond with its producing cause. The preceding experiments on the Rothesay mill are undoubtedly . correct and consistent with the principles of motion and power, and also with the experiments of Smeaton on mills and mechanical power. The mechanical power is as the quantity of water on the wheel, multiplied into its velocity when the wheel, fall, and other circumstances remain the same; and since the mechanical effect is measured by the resistance mul¬ tiplied into the velocity of the working point when the friction is constant, if the quantity of water be diminished by its half, either half the resistance, or half the velocity j with which it is overcome, must be I taken away, otherwise there will i not be an equilibrium between the powder and effect. But at the same j time it is to be observed, that an increased velocity lessens the fric¬ tion of the intermediate machinery, and consequently a greater effect would be produced by the greater velocity, as appears to be the case by the experiments. There is not, however, in the detail of these ex¬ periments, sufficient data by which it becomes easy to arrive at any any useful conclusion. WAT WATER-WHEEL. WAT Roberton, an engineer of some eminence, made observations on these experiments, alleging that the conclusions of Banks give most satisfactory evidence that particular care and judgment are necessary in making such trials. It appeared to Roberton, that the wrong con¬ clusions which have been drawn by many writers on this subject, have wholly arisen from misappre¬ hending someof Sir Isaac Newton’s fundamental principles of mecha¬ nics, and from a love of establish¬ ing theoretical expressions rather than strict observations of the in¬ variable laws of nature, expres¬ sions such as these, viz. quantity of motion, instantaneous impulse. Taking a constant portion of time (viz. a second) to be the measure of a body, and an instant to be the measure of the effect it produces ; or by taking time as the measure of the cause, and space as the measure of the effect,—as to an instantaneous effect, Roberton argues that it is an absurdity in itself, as well as in mechanics,— I we can form no idea of a body put into motion without the acting power or body act upon the body put into motion for some time, and also over some space; and to sup¬ pose otherwise, leads us entirely out of the sound principles of me¬ chanics. In mechanics every effect is equal to its producing cause. In the case of a power acting on a body pro¬ ducing motion, and also this body acting against another power which retards its motions, if the causes of action and resistance are each mea¬ sured by the time the motions are produced and retarded, the result will be equal. If they be measured by the space over which they act, the re¬ sults will be equal; and this is a universal principle, whether ap¬ plied to accelerating power and motion, as gravity, etc., or to ma¬ chines, which act constantly and uniformly. Yet, in the case of uniform motion, space or time may be used at pleasure; as from the uniformity of space and time they become a common measure. To illustrate this, suppose the body a acted upon by the power of gravity through the space a b, in a portion of time which we will call one. When it arrives at b, it meets with another medium of re¬ sistance, which is ten times greater than the former; the body a will be resisted in pro- a q portion to the cause of ac¬ tion and resistance; that is to say, if the time of i action were one second, the time of resistance will be one-tenth of a second, and the distance a b will be to the distance b c as ten to one; sothat whether space or time be taken as the measure of action, the , same must be taken for j the measureof the effect to ha ve the results propor¬ tionate and equal. But i if the cause be measured B by time, and the effect by space, the results will be as the squares of the time, c - or, which is the same thing, as the squares of the ve¬ locity. Thus, suppose a body in motion, with a velocity of one, has a power to penetrate into a bank of earth 1 foot: if the same body, with a velocity of two, strike the bank, will penetrate to the depth of 4 feet; for the velocity is double, and the time of action is double, and therefore the results will be compounded of both, that is, as the square of the velocity. From the above it may be in¬ ferred that if equal bodies be acted upon by unequal powers, the time requisite to produce an equal mo¬ tion will be reciprocally propor¬ tionate to the powers; that is to say, if a power of ten act upon a 547 WAT WATER-WHEEL. WAT body for one second of time, and the power of one act upon an equal body for ten seconds, they will pro¬ duce equal velocities. But the spaces through which the bodies (are carried are very Unequal, being as ten to one ; and if the square roots of the powers producing the effects be taken, that will give the times they take in carrying the j body acted upon through equal ! spaces. But it is obvious this doctrine has no more to do with the ope¬ ration of machines than to supply their first starting from rest to the motion necessary for working. When this is acquired, the power applied and the power of resistance balance each other, and whatever be ihe motion the machine moves at, the same power will carry it on, (if it be upheld,) provided the machine act in such a manner as not to accumulate resistance by the accumulation of motion, which is the case in forcing fluids through pipes, etc. In cases of this kind, the nature of the machine must be particularly kept in view, and no law whatever adopted to explain the resistancethe acting body meets with, but what is simply deduced from the very machine which is under consideration ; but, in most cases, any machine may be con¬ sidered as acting purely on a sta¬ tical principle. The raising of weights, or overcoming friction, Roberton considers purely as act¬ ing on that principle; and when the power of action is equal to the resisting power, the machine is in¬ different to motion or rest. If the machine be at rest, the power will not move it, being a balance to the resistance. If the machine be set in motion, the power will keep it in the same motion, (provided the power be upheld,) the same as equal weights hung over a pulley, or in the opposite scales of a beam. If they be at rest, they will remain so ; and if they be put in motion, they will endeavour to persevere in the same. The above doctrine of a statical principle is proved in the most satisfactory manner by the experi¬ ments made at the old mill of Rothesay, the motion of the water¬ wheel being exactly proportional ! to the quantity of water expended, j and therefore an exact and equal load upon the wheel; that is to say, the buckets were equally full when the mill moved at its ordi¬ nary motion, or at half that mo¬ tion. The effect therefore of letting more water on a wheel is not to lodge a greater quantity in the buckets, but to supply the same quantity when the wheel is in a greater motion. Banks, however, made his ex¬ periments agree with his theory, yet Roberton took no trouble in ■ inquiring into them, alleging it would be to little purpose to have done so. “ Suffice it to say,” he adds, i “ that the very small quantities of water which Banks made use of,; and the slowness of the motion of ] his wheel in his experiments, give j no ground for placing the smallest, dependence on them; and when compared with the more judicious and accurate experiments of Smea- ton, they dwindle into contempt.” ; Roberton further says, that 1 “ Smeaton, in running his wheel' at nearly 3 feet in the second, 1 brought it nearly to a maximum, and lost but about one-fourth or one-fifth of the original effect (al¬ luding to his overshot wheels). Banks, at his highest motion, ran his wdieel about 1 foot in the se¬ cond, and reducing it to one-half of that motion, the same quantity of w'ater then expended was ca¬ pable of performing four times the work; and by deduction from thence, it appears plain that his wheel (from his own theory) would perform about twenty times the quantity of work which Smeaton’s 548 WATER-WHEEL, OVERSHOT. WAT : WAT could perform with the same quan¬ tity of water, and about sixteen | times more than nature; so that the observation (alluding to the theory of Banks) is very just in saying that, by reducing the mo¬ tion of the wheel, it is demon¬ strable it would raise more water than supply itself.” Water-wheel (Overshot). The best water-wheel is that which is cal¬ culated to produce the greatest effect when it is supplied by a stream which furnishes a given quantity of water with a given fall. The mechanical effect depends on the proportion of the wheel’s diameter to the height of the fall, and on the velocity of the circum¬ ference of the wheel. These are the two principal parts to be con¬ sidered in the theory of wheels, but there are also some other points which ought to be attended to, be¬ cause the effect is much decreased when they are neglected. Of the proportion of the radius of the water-wheel to the height of the fall. —Let a b c d he the wheel, and e a the depth of the buckets ; then, according to experiments on water-wheels, it appears that the rotatory form of the water in the buckets is nothing at c and d, and that it increases nearly, if not ac¬ curately, in the direct ratio of the distance from c or d, and is greatest at a. That is, the force at any point a in a direction e a, or per¬ pendicularly to the radius, is as ac. A > slight consideration of the figure is sufficient to demonstrate that the wheel will not produce the greatest effect when it receives the water at the upper point c, and that there must be considerable advantage in making the wheel of a greater diameter, so that it may receive the water at the same point between a and c, the point 549 2 a 3 WAT ■which will ensure the greatest ef¬ fect thus calculated. Let c = that portion of the cir¬ cumference which is to be loaded with water; and x = the arc com¬ prehended between the point where the water flows upon the wheel and the horizontal line e a ; also make b = the area of the stream supplying the buckets. Then the solid which represents the effective force will be which is to be the greatest possi¬ ble ; or c 9 — 2 x 9 C - X = a maximum. By the principles of maxima and minima this takes place when x — c (1 —- V £) or x— - 2929 c. Accordingly the arc c — x must be the quadrant dg or 90°, and the arc x = 37-27°- Hence we have this important practical maxim. A water-wheel will produce the greatest effect when the diameter of the wheel is proportioned to the height of the fall, so that the water flows upon the w'heel at a point about 52|° from the summit of the wheel. If r be the radius of the wheel to the extreme part of the bucket, and h the effective height of the fall, then h — r(l + sin. 37£), or h = 1-605 r\ forthe sin. 37£ ='605. Also '623 h = r. Therefore, when the effective height of the fall is determined, the radius of thewheel is easily calculated. When the ef¬ fective fall is eight-ninths of the whole fall, if we make h the whole fall, r='554 h , or 1*108 h — the diameter of the wheel. The effective height of the fall is less than the true height by as much as is necessary for giving the water the same velocity as the wheel before it flows upon it. In low falls a wheel would work WAT with advantage in a considerable depth of tail-water, provided the buckets were of a suitable form for moving through the water, andthe effective fall made through a very accurate sweep, so that the sweep, and not the form of the bucket, should confine the water upon the wheel. Of the velocity of the circum¬ ference of the wheel to produce a maximum effect. —It is necessary to premise, that the velocity with which the water flows upon the floating boards or buckets is con¬ sidered to be equal to the velocity of the wheel, and to strike against the floats as nearly as possible in the direction of the motion of the wheel. Let x be that part of the fall which gives the necessary velocity v to the water, when the effect is a maximum; v will then be the velocity of the circumference of the wheel. Also, make a = that part of the fall which would correspond to the velocity of the circumference of the wheel when the power would be equal to the friction of the loaded machine only; or when the useful effect would be nothing. Now if h be the whole fall, the effective force of the water on the wheel will always be proportional to h — x, when the effect is a maximum; and to h — a, when the useful ef¬ fect, or work done, is nothing. Hence v (h — x — h — a) must be a maximum ; or v (a — x) = a max.; but v = x therefore x * (a~x) — a max., which, according to the rules of maxima and minima, takes place when a = 3x. It is evident that the value of a must entirely depend on the nature of the machine: for if there be many moving parts between the power and the resistance, the fric¬ tion will be greater,and consequent¬ ly a will be less. The machine WATER-WHEEL, OVERSHOT. 550 WAT WATER-WHEEL, OVERSHOT. WAT must be very simple indeed, if the friction be less than one-half the moving power, and it will often amount to two-thirds of it. If we suppose it to be two-thirds, then h o. -, and consequently and h 9’ 164 Th =2-67 a/A. v = V- Hence, when the friction amounts to two-thirds of the moving power, the velocity of the circumference of an overshot wheel in feet per second, should be 2-67 times the square root of the whole height of the fall, in feet. Again, that part of the fall is to be determined, which will give the water the same velocity as the wheel: and since 3’ and Zx = a, we have h x =—. 9 Hence, when the friction is two- thirds of the power, that part of the fall which will give the water the proper velocity is one-ninth of the whole height. These results may, then, be use¬ fully compared with the experi¬ ments of Smeaton; at the same time it is obvious that his experi¬ ments were not adapted for arriv¬ ing at general conclusions, because the water was always delivered upon the same wheel: for it is clear, from the preceding investi¬ gation, that every particular wheel must have its particular maximum. In Smeaton’s experiments on overshot wheels, the wheel was 2 feet in diameter; therefore the height of the fall should be 2\ feet. Now the square root of 2£ is 1*5 ; and 1-5 x 2 - 67 = 4 , 005, that is, the velocity of the wheel should be 4 feet per second; or it should make 38 turns per minute. Smea¬ ton infers that “ the best velocity for practice ” will be when awheel of 2 feet diameter makes 30 revo¬ lutions per minute. (Miscellaneous Papers, p. 51.) But his model had much more friction in proportion to the etfective force of water on the wheel than two-thirds, here calculated upon. When, however, the calculation is made according to the friction of Smeaton’s model, v = 2-4 -Jh ; and the velocity of the model wheel would come out 3'6 feet per second, or 34 turns per minute. This ve¬ locity will perhaps apply correctly enough to overshot wheels, where the water flows on at the summit, and to rough-made machinery; but the former calculation is that which appears to be most correct for the improved kind of wheels here pointed out. It is to be under¬ stood, that the friction allowed for includes all the kinds of resistance and loss of force which lessen the useful effect, as well as the resist¬ ance of the rubbing surfaces, pro¬ perly called friction. Many persons may think that two-thirds of the effective force is greatly too much to be lost'; it will be well if it draw their attention to lessening the stress on every part of the machi¬ nery, and to the importance of having few rubbing surfaces, and other causes of resistance. On computing the power of over¬ shot water-wheels .—In determin¬ ing the proportion of the r^ius of the wheel to the height of the fall, an equation is given for the effec¬ tive force. Resuming that equa¬ tion, we have /c 2 — 2x\ = the effective force of the water, and 551 "WAT WATER-WHEEL, OVERSHOT. WAT I = its mechanical power. But the quantity of water expended in maintaining this power will be b v. Hence, the quantity of water ex¬ pended is, to its mechanical power, as When the wheel is supplied at the summit, x — % c ; and there¬ fore the quantity of water ex¬ pended is to its mechanical power as 1 : ^ c. Or the power is equal to half the weight of water sup¬ plied to the wheel. The same relation takes place when x = 0; that is, when the wheel is supplied at the height of the axis. Hence, when the radius of a breast-wheel is equal to the effective height of the fall, its power will be the same as that of an overshot wheel supplied at the summit. When the wheel is supplied at the point which produces the greatest effect, x = -2929 c ; and consequently the quantity of water expended is to its mechanical power as 1 . 0-5857 c: this effect is greater than when the wheel is supplied at the summit in the ratio of 1-1714 : 1. These comparisons will convey some useful information to many readers ; and they may sometimes suggest to scientific writers the advantage of studying the actual nature of machines; for relations so extremely obvious and simple couifcd never have been overlooked by any one who might have con¬ descended to apply himself to an examination of the subject. The power of a water-wheel may be considered under two points of view ; each of which has its pecu¬ liar use. If w'e wish to compare it with any other first mover, then w-e shall have to calculate its me¬ chanical power. But when it is desirable to compute the resistance it will overcome at the working point, the effective force should be calculated. When the water flows upon the wheel, either at or above the axis,' the mechanical power is c 2 — 2 x' z i b v - c — x cubic feet of water, or _ O m2 31-25 bv -—lbs.; w'here b v is the quantity of water expended in a second, in cubic feet; c the part of the circumference be¬ tween the lowest point of the wheel and the place where the water flows upon it, in feet; and x the part of the circumference between the point which is level with the axis, and that where the water flow's upon the wheel, in feet. Suppose the mechanical power of ahorse is estimated at 200 lbs., moving with a velocity of 3f feet per second, then a water-wheel will be equal 3_ y25 b v (c 2 — 2# 2 ) horses 200 x 3§ (e — x) "00426 b v (c 2 — 2 a?) , ——-horses. When the water flows on either at the summit or at the level of the axis, the mechanical power is 31-25 b v c lbs., or it is = 0-00426 b v c horses. When the water flows on at 52| degrees distant from the summit, the mechanical power is 37-192 b v c lbs., or = -005 b v c horses. Since in this case e=127} degrees of the circumference, w-e have c= 127£ x -0174533 r; and as r — •554 h; and v =2-67 ■/ h\ by substituting these quantities, we have 122-176 b lbs. = the me¬ chanical power; or -0164 bhJ = the number of horses, where h = 552 WAT WATER-WHEEL, VENTILATED. WAT the whole height of the fall, in feet, and £ = the area of the aperture through which the water flows upon the wheel, in feet. The effective force is 31*25 b c lbs. when the water flows on either at the summit or at the level of the axis. When the water flows on at 52f degrees distant from the summit of the wheel, the effective force is 37*192 b c lbs. or 45*746 b h lbs. Of the power of breast-wheels .— When the water flows on below* the level of the axis of the wheel, it may be termed a breast-wheel. Let y be the distance below the axis measured on the circumfer¬ ence, then cr b v 2 (c + y) equal the mechanical power in cubic feet of water, or 31 ' 25 ^ lh, c + y When y = c the power will be re¬ duced one-half, and when y = 2 c it will be reduced two-thirds, and so on. If we assume that the mechani¬ cal power of an undershot wheel is half that of an overshot one “ under the same circumstances of quantity and fallthen it will be an ad¬ vantage to employ an undershot wheel whenever the fall is less than three-tenths of the radius of the wheel. But since the radius of the wheel may in many cases be di¬ minished, it does not appear to be desirable to employ an undershot wheel in any case, except where the quantity of water is great and the fall inconsiderable. Water-wheel with ventilated Buckets. Since the time of Smeaton’s expe¬ riments in 1759, little or no im¬ provement has been made in the principle on which w*ater-wheels have been constructed. The sub¬ stitution, however, of iron forwood, as a material for their construction, has afforded opportunities for ex¬ tensive changes in their forms, par¬ ticularly in the shape and arrange¬ ment of the buckets, and has given altogether a more permanent and lighter character to the machine than had previously been attained with other materials. A curvili¬ near form of bucket has been gene¬ rally adopted, the sheet iron of w*hich it is composed affording fa¬ cility for being moulded or bent into the required shape. From a work entitled ‘ Meca- niquesetlnventions approuvees par l’Academie Royale des Sciences,’ » published at Paris in 1735, it ap¬ pears, that previous to the com¬ mencement of the last century, neither the breast nor the overshot water-wheels were much in use, if at all known ; and at what period and by whom they were introduced, is probably equally uncertain. The overshot wheel was a great im¬ provement, and its introduction was an important step in the perfecting of hydraulic machines; but the breast-wheel, as now generally made, is a still further improve¬ ment, and is probably better calcu¬ lated for effective duty under the circumstances of a variable supply of water, to which almost every description of water-wheel is sub¬ jected. Improvements have taken place during the last and the pre¬ sent centuries. The breast-wheel has taken precedence of the over¬ shot wheel, not so much from any advantage gained by an increase of power on a given fall, as from the increased facilities which a wheel of this description, having a larger diameter than the height of the fall, affords for the reception of the water into the chamber of the bucket, and also for its final exit at the bottom. Another advantage of the in¬ creased diameter is the comparative ease with which the wheel over¬ comes the obstruction of back¬ water. The breast-wheel is not 553 WATER-WHEEL, VENTILATED. WAT only less injured from the effects of floods, but the retarding force is overcome with greater ease, and the wheel works for a longer time and to a much greater depth in hack-water. The late Dr. Robison, Professor of Natural Philosophy in the Uni¬ versity of Edinburgh, in treating of water-wheels, says, “ There fre¬ quently occurs a difficulty in the making of bucket-wheels, when the half-taught millwright attempts to retain the water a long time in the buckets. The water gets into them with a difficulty which he cannot account for, and spills all about*, even when the buckets are not moving away from the spout. This arises from the air, which must find its way out to admit the water, but is obstructed by the entering water, and occasions a great sput¬ tering at the entry. This may be entirely prevented by making the spout considerably narrower than the wheel: it will leave room at the two ends of the buckets for the escape of the air. This obstruction is vastly greater than one would imagine ; for the water drags along with it a great quantity of air, as is evident in the water-blast as de¬ scribed by many authors.” In the construction of wheels for high falls, the best proportion of the opening of the bucket is found to be nearly as five to twenty-four; that is, the contents of the bucket being 24 cubic feet, the area of the opening, or entrance for the water, vrould be five square feet. In breast-wheels which receive the water at the height of 10° to 12° above the horizontal centre, the ratio should be nearly as eight to twenty-four, or as one to three. With these proportions, the depth of the shrouding is assumed to be about three times the width of the opening, or three times the distance from the lip to the back of the bucket, as from a to b, fig. 1, the opening being 5 WAT inches, and the depth of the shroud 15 inches. Fig. 1. For lower falls, or in those w heels which receive the water below the horizontal centre, a larger opening becomes necessary for the recep¬ tion of a large body of water, and its final discharge. In the construction of water¬ wheels, it is requisite, in order to attain the maximum effect, to have the opening of the bucket suffi¬ ciently large to allow an easy en¬ trance and an equally free escape for the water, as its retention in the bucket must evidently be in¬ jurious, when carried beyond the vertical centre. Dr. Robison further observes, “ There is another and very seri¬ ous obstruction to the motion of an overshot or bucketed wheel. When it moves in back-water, it is not only resisted by the w r ater when it moves more slowly than the wheel, which is very frequently the case, but it lifts a great deal in the raising buckets. In some 554 WATER-WHEEL, VENTILATED. WAT WAT particular states of back-water, the descending bucket fills itself com¬ pletely with water, and in other cases it contains a very considerable quantity, and air of common den¬ sity, while in some rarer cases it contains less water, with air in a condensed state. In the first case, the rising bucket must come up filied with water, which it cannot drop till its mouth gets out of the water. In the second case, part of the water goes out before this; but the air rarefies, and therefore there is still some water dragged or lifted up by the wheel, by suc¬ tion, as it is usually called. In the last case, there is no such back- load on the rising side of the wheel, but (which is as detrimental to its performance) the descending side is employed in condensing air; and although this air aids the ascent of the rising side, it does not aid it so much as it impedes the descend¬ ing side, being (by the form of the bucket) nearer to the vertical line drawn through the axis.” These were the difficulties under which the millwrights of Dr. Ro¬ bison’s time laboured; and the remedy which they applied (and which has since been more or less .continued) was to bore holes in what is technically called the ‘ start’ of the bucket. This was the only means adopted for removing the air from the buckets of overshot wheels, in order to facilitate the admission and emission of the water. In lower falls, where wheels i with open buckets were used, or ' straight float-boards radiating from i the centre, large openings were made in the sole-planking, exclu¬ sive of perforations in each bucket, in order to relieve them from the condensed air. The improved con¬ struction of the present time is widely different, the buckets being of such a shape as to admit the I water at the same time that the i air is making its escape. During the early part of 1825, ' and the two succeeding years, two iron water-wheels, each of one hundred and twenty horse power, were constructed in Manchester for Messrs. James Finlay and Co., of the Catrine Works, under the auspices of the late Mr. Buchanan, and also for the same Company at Deanston, in Perthshire, of which firm Mr. James Smith (Deanston) was then the resident partner. These wheels are still (1850) in operation; and taking them in the aggregate, they may probably be considered as some of the most powerful and the most complete hydraulic machines in the United Kingdom. The construction of these wheels, and others for lower falls, first directed attention to the ingress and egress of the water, and led to the improvements which have since been introduced. The object of these modifications may be generally stated to have been for the purpose of preventing the condensation of the air, and for permitting its escape, during the filling of the bucket with wa¬ ter, as also its re-admission during the discharge of the water into the lower mill-race. Shortly after the construction of the water-wheels for the Catrine and Deanston Works, a breast- wheel was made and erected for Mr. Andrew Brown of Linwood, near Paisley. In this it was ob¬ served, when the wheel was loaded, and in flood-waters, that each of the buckets acted as a water-blast, and forced the water and spray to a height of six or eight feet above the orifice at which it entered. This was complained of as a great defect, and, in order to remedy it, openings were cut in the sole- plates, and small interior buckets were attached to the inner sole, as shown at b, b, b, fig. 2. The air in this case made its escape through the openings a, a, a, into the inner bucket, and passed upwards, as is shown by the arrows, through b, b, b, 555 WAT WATER-WHEEL, VENTILATED. WAT Fig. 2. into the interior of the wheel. By these means it will he observed that the buckets were effectually cleared of air whilst they were filling, and that during the ob¬ structions of back-water, the same facilities were afforded for its re¬ admission, and the discharge of the water contained in the rising buckets. The effect produced by this alteration could scarcely be credited, as the wheel not only received and parted with the water freely, but an increase of nearly one-fourth of the power was ob¬ tained, and the wheel, which still remains as then altered, continues, in all states of the river, to per¬ form its duty satisfactorily. The amount of power gained, and the beneficial effects produced upon Mr. Brown’s wheel, induced a new and still greater improve¬ ment in the principle of construc¬ tion : the first wheel erected on this, which has been called the ‘ ventilated ’ principle, was one de¬ signed for Mr. Duckworth, at the Ilandforth Print-Works, in the neighbourhood of Wilmslow, in Cheshire. Close-bucketed wheels labour under great difficulties when re¬ ceiving the water through the same orifice at which the air es¬ capes, and in some wheels the forms and construction of the buckets are such as almost entirely to prevent the entrance of the wa¬ ter, and to deprive the wheel of half its power. These defects may be easily accounted for where the water is discharged upon the wheel in a larger section than the opening between the buckets: under such circumstances the air is suddenly condensed, and, re-acting by its elastic force, throws back the wa¬ ter upon the orifice of the cistern, and thus allows the buckets to pass without their being more than half-filled. Several methods have been adopted for relieving them of the air: the most common plan is, by cutting holes in the sole-plates, close to the back of the buckets, or else making the openings be¬ tween them much wider, in order to admit the water, and at the same time to allow the air to es¬ cape. All these remedies have been more or less effective; but they labour under the objections of a great waste of water and much inconvenience, by the water falling from the openings down upon the lower part of the wheel, exclusive of the puffing and blowing whop the bucket is filling. Other remedies have been ap¬ plied, such as circular tubes and boxes attached to the sole-plates, which, extending upwards, furnish openings into the interior of the wheel for the air to escape; but these, like many other plans, have | been, to a certain extent, unsuccess¬ ful, owing to the complexity of their structure, and the inadequate manner in which the objects con* templated were attained. In fact, in wheels of this description it has been found more satisfactory to I submit to acknowledged defects, than to incur the trouble and in¬ convenience of partial and imper- feet remedies. In the improvements made by 556 WAT WATER-WHEEL, VENTILATED. WAT Mr. Fairbairn, these objections are to a great extent removed, and a thorough system of ventilation has been effectually introduced. Be¬ fore entering upon the description of this new principle of ventilation, it is necessary to remark, that in climates like Great Britain and Ire¬ land, where the atmosphere is charged with moisture for six or seven months in the year, it is no uncommon occurrence for the rivers to be considerably swollen, and the mills depending upon wa¬ ter are either impeded or entirely stopped by back-water; while at other times a deficiency of rain re¬ duces the water-power below what is absolutely required to drive the machinery. On occasions of this kind, much loss and inconvenience are sustained, particularly in mills exclusively dependent upon water as a motive power, and where a number of work-people are em¬ ployed. On the outskirts of the manufac¬ turing districts, where the mills are more or less dependent upon water, these inconveniences are se¬ verely felt; and in some situations these interruptions arise as fre¬ quently from an excess of water as from a deficiency in the supply. To remedy these evils, reservoirs have been formed, and wheels have been constructed to work in floods ; but although much has been ac¬ complished for diminishing these injurious effects, and giving a more regular supply in dry seasons, yet the system is still imperfect, and much has yet to be done, before water can be considered equal, as a motive power, to the steam engine, which is always available where the necessary fuel is at hand. It is therefore obvious, that any im¬ provement in the construction of water-wheels, whereby their forms and requirements may be better adapted to meet the exigencies of high and low waters, will contri¬ bute much to the efficiency and value of mills situated upon rivers subjected to thechangesalluded to. Water-wheels (Ventilated) as adap¬ ted to low falls .—The first wheel constructed upon the ventilated principle was erected at Handforth, in Cheshire, in the summer of 1828 : it proved highly satisfactory to the proprietors, Messrs. Duck¬ worth and Co., and gave such im¬ portant results as to induce its re¬ petition, without variation, in cases where the fall did not exceed the semi-diameter of the wheel. In the earlier construction of iron suspension wheels by the late Mr. J. C. Hewes, the arms and braces were fixed to the centres by screws and nuts upon their ends, as shown in fig. 3. The arms c, c, passed through the rim b, b, and Fig. 3. the braces e, e, which traverse the angle of the rim /’, f are, as nearly as possible, in the position and WAT WATER-WHEEL, BREAST. form adopted by Mr. Hewes. This arrangement, although convenient for tightening up the arms and braces, was liable to many objec¬ tions, arising from the nuts be¬ coming loose, and the consequent difficulty of keeping the wheels true to the circle, and the arms and braces in a uniform state of tension : gibs and cotters were therefore substituted for the nuts and screws, and since their intro¬ duction into the large wheels of the Catrine Works, Ayrshire, the objections have been removed, and the arms and braces are not only perfectly secured, but the peri¬ phery of the wheel is retained in its true and correct form. Having noticed the obstructions offered to the entrance of the wa¬ ter into buckets of the usual form, and the consequent loss which en¬ sues from its retention upon the wheel, after its powers of gravita¬ tion have ceased, it is now neces¬ sary to show the means whereby those defects were removed, and also to exhibit the relation existing between the breast and the under¬ shot wheels. These terms have, however, become nearly obsolete, as every description of water-wheel may now be properly called a breast-wheel; and in every fall, however low, it is generally found advantageous for the water to act by gravitation, and not by impulse, as during the early periods of the industrial arts. Water-wheels (Breast), with close Soles and ventilated Buckets. The preceding statements have been principally confined to the form of buckets and description of water¬ wheel adapted for low falls. It is therefore necessary to describe the best form of breast-wheels for high falls, or those best calculated for attaining a maximum effect on falls varying from one-half to three- fourths of the diameter of the wheel. This is a description of water-wheel in common use, and WAT is generally adopted for falls which do not exceed 18 feet in height, and, in most cases, is pre¬ ferable to the overshot wheel. It possesses many advantages over the undershot wheel, and its near ap¬ proximation to the duty, or labour¬ ing force, of wheels of the former description, renders it applicable in many situations, especially where the fall does not exceed 18 or 20 feet, and where the wheel is ex¬ posed to the obstructions of back¬ water. In the latter case, wheels j of larger diameter are best adapted; and provided sufficient capacity is left in the buckets, such wheels may be forced through the back¬ water without diminution of speed. Every wheel of this kind should have capacity in the buckets to re¬ ceive a sufficient quantity of water to force the wheel, at full speed, through a depth of 5 or 8 feet of back-water; and if these provisions are made, a steady uniform speed, under every circumstance of freshes and flood-waters, may be attained. Irrespective of the advantages of clearing the buckets of air, ad¬ ditional benefit is obtained by the facility with which the water is discharged, and the air again ad¬ mitted, at the bottom of the fall, during the period of the emptying of the bucket into the tail-race. This is strikingly illustrated where the wheels labour in back-water, as the ventilated buckets rise freely above the surface, and the commu¬ nication being open from one to the other, the action is rendered perfectly free, at almost any depth to which the wheel may be im¬ mersed. In breast-wheels constructed for falls of 25 feet or upwards, the stone-breast is not required, as the buckets are formed with narrow openings, and the lip being ex¬ tended nearer to the back of the following bucket, the water is re¬ tained much longer upon the wheel. Under these circumstances, astone- 558 WAT WATER-WHEEL, BREAST. WAT breast is of little or no value, when attached to a wheel with close buckets, on a high fall. The construction of the breast- wheels, as above described, is al¬ most exactly similar to that for the lower falls; malleable iron arms and braces being common to both, as also the axle, shroud, and seg¬ ments. These, when duly pro¬ portioned and properly fitted to each other, form one of the strong¬ est, and probably the most per¬ manent structures, that can be at¬ tained in works of this description. Water-wheel (common Breast, not ventilatedJ, as constructed by Messrs. Fairbairn and Lillie, be¬ tween the years 1825 and 1827. These wheels were executed upon the plan of the overshot or breast- wheel, taking the water at an ele¬ vation nearly equal to that of its height. Four wheels of this description were constructed for Messrs. James Finlay and Co., for a fall of 32 feet, at Deanston, in Perthshire, and two others, for the same firm, at the Catrine Works, in Ayrshire, on a fall of 48 feet. Taking into consideration theheight of the fall, the Catrine waterwheels, both as regards their power and the solidity of their construction, are, even at the present day, pro¬ bably among the best and most effective structures of their kind in existence. They have now (1850) been at work upwards of twenty years, during which time they have required no repairs, and they re¬ main nearly as perfect as when they were ereated. It was originally intended to have erected four of these wheels at the Catrine Works, but only two have been constructed ; prepara¬ tions were, however, made for re¬ ceiving two others, in the event of an enlargement of the reservoirs in the hilly districts, and more power being required for the mills. This extension has not yet been want¬ ed, as these two wheels are equal 559 to 240 horse-power, and are suffi¬ ciently powerful, except in very dry seasons, to turn the whole of the mills. These water-wheels are 50 feet in diameter, 10 feet 6 inches wide in¬ side the bucket, and 15 inches deep on the shroud; the internal spur- segments are 48 feet 6 inches dia¬ meter, 3^ inches pitch, and 15 in¬ ches broad on the cog; the large spur-wheels are 18 feet 2^ inches in diameter, 3£ inches in the pitch, and 16 inches wide on the cog; and the pinions are the same width and pitch, but are 5 feet 6 inches in diameter; the large bevel-wheels are 7 feet in diameter, 3£ inches in the pitch, and 18 inches broad on the cog, their proportions being calculated to convey the united power of all the four water-wheels, should the original design ever be completed. The water for the supply of the wheels is conveyed from the river Ayr in a canal and tunnel, and from thence, along the side of a rising bank, to the wheel-house. From this point it is conveyed to the water-w'heels by a large sheet- iron trough, supported on iron columns. When viewed from the entrance, the two wheels already erected have a very imposing effect, each of them being elevated upon stone piers; and as the whole of the cisterns, sluices, winding apparatus, gal¬ leries, etc., are considerably ele¬ vated, they are conveniently ap¬ proached in every part. Under the wheels is a capacious tunnel, terminating at a considerable dis¬ tance down the river. Water-wheels on a principle in¬ troduced by M. Poncelet, have at¬ tained some considerable reputa¬ tion on the Continent; and as Mr. Fairbairn has constructed one of them for Mr. De Bergue, it is ne¬ cessary to allude briefly to the pe¬ culiarities it possesses. The buckets are of a curvilinear WAT WATER-WHEEL, BREAST. WAT form, and are quite open at the back, without any sole-plate; so that they are perfectly ventilated. The water impinges upon them at nearly the lowest point of the wheel, the shuttle being arranged to draw upwards ; and as the wa¬ ter enters, it follows the inside ca¬ vity of the bucket, rises and falls over into the next in succession, and so on. By this system the force of the water is expended on the wheel itself, instead of losing much of its power in rushing along through the wheel-race, as ge¬ nerally occurs in even well-made undershot wheels. M. Poncelet has treated this subject at much length in his able work on water-wheels ; but it may be observed, that a practical im¬ provement might be effected by terminating the lower stone plat¬ form of the race somewhat short of the vertical line of the centre of the wheel, as the escape of the water would be facilitated, and the ascending buckets would be more easily relieved of their contents: this is a point of such importance for all wheels, that it must equally apply to this form. Mr. De Bergue obtained nearly seventy-eight per cent, of power from a breast-wheel, with a good fall, when the periphery was tra¬ velling at a velocity of 6 feet per second. He has erected several of Ponce- let’s wheels, and thought well of them; indeed, for certain situa¬ tions it was thought they were pre¬ ferable to any other form, although M. Poncelet had never yet been able to obtain very superior results from wheels erected under his own superintendence. Mr. De Bergue has explained the construction of a wheel, on this principle, erected at the Loubre- gat, near Montserrat, in Catalonia; one of the same kind having been already erected by him at Gerona, between Barcelona and Belgrade. The diameter was 16 feet 8 inches, and the width was 30 feet, which, with a fall of 6 feet 6 inches, passed 120,000 cubic feet of water per minute, when the periphery travelled at a velocity of 11 to 12 feet per second. An or¬ dinary breast-wheel would require to be 60 feet wide, to use advan¬ tageously that quantity of water. It was found that the velocity of the periphery should be about 55 i per cent, of that of the water flow¬ ing through the sluice ; and upon these data the power of the wheel would be about 180-horse power. The buckets were of a curved form, and made of wrought iron, i gth of an inch thick ; and it should n be observed that there was a larger ; number of buckets than usual, and that the water came upon them a at a tangent, through an orifice of such a form and dimensions as to allow the buckets to fill easily, at the rapid speed at which the peri¬ phery passed before the sluice, i This great primary velocity was I very important, as it caused a con- I siderable saving in the gearing of j I the mill. The main shaft was formed by j , a hollow cylinder of cast iron, 4 j feet 6 inches diameter, in short j lengths, bolted together; and the | arms were of wrought iron, made j very light, and of the same form j as those of a paddle-wheel of a \ steamer, and placed very close to¬ gether. The strain was brought entirely upon the main shaft, and the weight of the wheel was thus reduced to about thirty tons, which was very little for so powerful a machine. The sluice was formed of cast- iron plates, with planed joints, bolted through the flanches, to form one large shuttle of the en¬ tire breadth of the wheel, and its motion was regulated by radial tie- rods, between the stone apron and; the back of the sluice, which couldj thus be raised with great facility 560 Ponceiet’s Water wheel, erected by Mr. l)e Bergue at the Loubregat, near Montserrat,in Catalonia. 561 WAV WEALDEN. WEI by racks and pinions, and be re¬ gulated by the ordinary governor, the weight of the sluice being in a great degree supported by the water flowing beneath it on to the wheel. It moved very accurately between the side walls of the pen- trough, and cup-leathers at each side prevented any waste of water. This kind of wheel was less affected by back-water than any other form, and the water acted upon it with its full power of velocity, without any impediment from the air in entering, as there was no sole-plate: the buckets filled and emptied with great fa¬ cility. It is therefore most satis¬ factory for all falls under 8 feet in height, though the principle dif¬ fers essentially from that generally taken as the basis of construction of water-wheels. JFaved, in heraldry, an indented out¬ line, indicating honours originally acquired at sea. Way-shaft, in steam engines, the rocking-shaft for working the slide- valve from the eccentric. Wax , the substance of which the honeycombs of bees are composed, and which is of considerable use in branches of art. Wealden. Beneath the two great divisions of the Cretaceous system, and consequently of very ancient date, there occurs in England an important series of beds, chiefly of lacustrine or fluviatile origin, known as the Wealden. Before the submergence of what are now the south-eastern parts of England, first beneath the comparatively shallow greensand, and then be¬ neath the profounder depths of the ocean of the chalk, a mighty river, the drainage of some unknown continent, seems to have flowed for many ages along those parts of Kent, Surrey, and Sussex, known as the Valley of the Weald. The banks of this old nameless river were crossed with forests of coniferous trees of pine and arau- carian families, with cycadeae and ferns, and were haunted by gigan¬ tic reptiles, herbivorous and car¬ nivorous, some of which rivalled in bulk the mammoth and the ele¬ phant; its waters were inhabited by amphibia of the same great class, chiefly crocodiles and chelo- nians of extinct species and type, —by numerous fishes too of the old Ganoid order, and by shells whose families, and even genera, still exist in our pools and rivers, though the species be all gone. Winged reptiles too occasionally flitted amid its woods, or sped ; over its broad bosom ; and insects of the same family as that to which our dragon-flies belong, spent the ! first two stages of their existence at the bottom of its pools and shallows, and the terminal one in darting over it on their wings of delicate gauze, in quest of their prey. It is stated by Dr. Mantel], ] our highest authority on the sub¬ ject of the Weald, that the delta of this great river is about two i thousand feet in thickness,—a I thickness which quadruples that | of the delta of the Mississippi. The American “ Father of Waters” is a very ancient river; and yet it, would seem that this river of the Wealden, which has now existed for myriads of ages, is but its fos¬ silized remains, hidden under the wolds of Surrey and Kent. This, old river, which flowed over when the ocean of the Oolite once hat been, and in turn gave place, ant was overflowed by the ocean o i the chalk, continued to roll itp downward waters amid forests a dense and as thickly inhabited a those of the great American valle during a period perhaps four time as extended. Weathercock, a vane made in th shape of a cock. Weather-gage, in navigation. When ship is to windward of anothe she is said to have the weathe gage of her. ; ^ 562 WEI . WEIGHTS AND MEASURES. WEI Weather-moulding, a label, canopy, or drip-stone, over a door or window, intending to keep off water from the parts beneath. Wedge. The wedge is a solid piece of wood or metal, generally made in 'he form of a triangle prism, of which the two ends or bases are equal and similar plane triangles, and the three sides rectangular parallelograms: and it is called rectangular, isosceles, or scalene, according as its equal and similar bases are composed of right angles, isosceles, or sealene triangles. As a mechanical power, the wedge performs its office, sometimes in raising heavy bodies, but more fre¬ quently in dividing or cleaving them; hence all those instruments which are used in separating the parts of bodies, such as axes, adzes, knives, swords, coulters, chisels, planes, saws, files, nails, spades, etc., are only different modifica¬ tions that fall under the general denomination of the wedge. Weighhoard, in mining, clay inter¬ secting a vein. Weight and power, when opposed to one another, signify the body to be moved and the body that moves it. That body which communi¬ cates the motion is called the power, and that which receives it I the weight. Weights and Measures. The system of weights and measures used in France at present, in all legal transactions, is called the ‘ me¬ trical system,’ from the fact of its being based upon the unityof length, which is designated ‘ the metre.’ Before the great revolution of 1793, the separate provinces of the French kingdom had their different systems of measures: just as in England the different counties had 1 theirs, before the introduction of the imperial measures. There was, consequently, the same confusion attached to the meanings of the 1 different terms employed, which ) led our own Government to sim¬ plify the question. An acre in Normandy did not mean the same as an acre in Picardy; a pound in Paris differed from a pound else¬ where. But here the analogy be¬ tween the conduct of the two Governments ceases. That of France reformed the whole system of weights and measures, and based the new one upon natural and easily verifiable principles,—whilst our own retained the arbitrary and illo¬ gical system of the middle ages, contenting themselves with merely fixing a sort of uniformity in the definitions of the several terms. The merit of having originated the metrical system is due to the government of Louis XV., who named a commission to pursue the investigations necessary to decide the principles upon which it was to be carried out. After a very se¬ rious consideration of the case, and a numerous series of observations carried on during the reign of Louis XVI. and under the Con¬ vention, the Academy of Sciences decided that all the different weights, measures, and coinages should be established according to certain definite relations to the di¬ mensions of the globe itself. These are, to all human perception, inva¬ riable. If therefore the standard were lost, it is always possible to refind it, by a repetition of the same sort of observations which gave rise to the fixing it in the first instance. The beat of a pendulum, chosen by our own Astronomical Board, is a very uncertain base for such calcu¬ lations; for the conditions of the vacuum, the temperature of the atmosphere, the specific gravity of the pendulum, nay, perhaps, even the magnetic currents, may affect the length of the space it goes through, in a manner able to af¬ fect calculations which require such mathematical exactitude as those connected with ascertaining the standard of a perfect system of measures. 563 WEI WEIGHTS AND MEASURES. ^ WEI The length of the earth’s meri¬ dian was ascertained by Messrs. Delambre and Mecbain, in tbe por¬ tion between Dunkerque and Bar¬ celona; and by Messrs. Arago and Biot, in the portion between Bar¬ celona and Formentera, The length of the meridian from the pole to the equator, passing through Paris, was then divided into ten million parts; and one of these parts, called the metre, became the basis of the new system of weights and measures. Maupertuis had previously, in the year 1736, measured a portion ot the arc of a meridian passing through the North Cape, and his observations were combined with those of the second commission. In spite of all this care, however, an error was made in fixing the length of the metre; for the dis¬ tance from the equator to the pole is really 10,000,738 metres, instead of 10,000,000. For any practical purpose, however, this error is in¬ applicable; but it is very unfortu nate. v 'Phe length of tbe metre once as¬ certained, the other measures were derived from it. All the multiples and sub-multiples were formed on the decimal system, and respec¬ tively designated by Greek and Latin prefixes to the name of the unities. Thus, the multiples of the metre are the rfees-metre, ten me¬ tres ; the Ucto- metre, a hundred metres; the Aifo-metre, a thousand metres; the myria- metre, ten thou¬ sand metres. In deference to old customs the term ‘league has been retained, and a legal value of four kilometres affixed to it. The sub-multiples of the metre are: the deci- metre, the tenth part of a metre; the centi-metxe, the hundredth part of a metre; and the milli-metre, the thousandth part of a metre. The same prefixes are, of course, applicable to all the other uni- The unities of length in use for ascertaining the distances of places, are, as said before, the metre (the [ kilometre and the myriametre) and j tbe league. ... . The unity of surface is tbe are, which is a square of ten metres on a side, or one hundred superficia metres. The usual multiples and sub-multiples are, the hect- are, a square of one hundred metres on a side ; and the centi- are, the metre j superficial. The terms usually era- j ployed in the sale of land and in j agricultural discussions, are simply those named above. . j The unity of weight is the ; < gramme,’ which is the equivalent j of a cube of distilled water (at a temperature of 4° above the ‘ ice- , melting point’ of the centigrade scale),measuringacentimetre every , wav. The multiples and sub-mul-i j tipies are, as before: the deca¬ gramme, ten grammes ; the hecto-11 gramme, a hundred grammes ; the | kilogramme, a thousand grammes; the decigramme, a tenth part of, a gramme, etc. A thousand kilo¬ grammes, then, would form a cube equal to one measuring a metre on every side; and it is made the legal ton for heavy weights. °The unitv of capacity is the < litre,’ which is the equivalent of a cube measuring one-tenth part ot a metre, or a decimetre, every way. The multiples and sub-multiples are formed as before. They are, the decalitre, the hectolitre, the kilolitre, the decilitre, and the cen¬ tilitre, etc. The litre is usually employed in expressing the quan¬ tities of liquids; the hectolitre expressing those of gram. A thousand litres of water thus are equal to a metre cube every wav, and are one ton m weight Another advantage in this systerr is, that the tables of specific gra¬ vity serve at once to ascertain the weights of the different substances Thus, inasmuch as the speci gravity of cast iron is /202, hi , weight of a metre cube is at one | 564 WEI WEIGHTS AND MEASURES. WEI 7202 kilogrammes, or 7 tons 202 the equivalent of the old ‘ ponce kilogrammes. fontanier,’ or the quantity usually The ‘franc,’ the unity of the delivered bv a hole of one inch French coinage, is 5 grammes in diameter in the 24 hours. weight of an alloy containing nine The law promulgating the me- parts of pure silver to one of alloy, trical system was dated in the year being thus connected with the 1795. The forced application of whole metrical and decimal system. it in legal transactions did not take As investigations connected with place till nearly 50 years after- the supply of water are of great wards. importance, it may be added, that A Table is subjoined of the dif- the quantity reckoned as the unity ferent French weights and mea- in such calculations is the module sures, with the corresponding Eng- or 20 cubic metres ; being nearly lish equivalents. Weights and Measures — French , with their English equivalents. French. WEIGHT. English. Gramme . . . f a cube of one-hundredth of a * 15*438 grains troy ‘ \ a metre on a side Kilogramme . . f a thousand grammes, or a cube' . < of waterone-tenthofamiltre 1 on a side. ^2*68026lbs. troy *2*20549 lbs. avoirdupois La tonne . . . | 1000 kilogrammes, or a cube of )> 6 n <. water 1 metre on a side . i English Troy. Reciprocally. French. Grain .... . equal to . 0*06477 gramme Pennyweight . • . 1*55456 „ Ounce .... . . • . 31*0913 grammes Pound Troy (Imperial) • »J • . 0*3730756 kilogramme Avoirdupois. Drachm , . equal to ■ . 1*7712 gramme Ounce .... • >> . 28*3384 grammes Pound .... 0*4534148 kilogramme Hundredweight . . . 50*7826 kilogrammes Ton • . . . • >» • 1015*649 „ To convert pounds avoirdupois into kilogrammes, or English tons into French tons, or vice versa, multiply or divide as follows : For pounds, by . . 0*4534148 For tons, by . 1*015649 French. LENGTH. English. [ about 40,000,000 th partofcir-"! | Metre .... 1 cumference of the globe, or * | 10-millionth part of a quarter 3*2808992 feet 1*093633 yard l of do. | Kilometre . . one thousand metres . 1093*633 yards Mvriam&tre . . ten thousand metres . . . 10936'33 yards p Centimetre . . one-hundredth of a m&tre 0 393708 inch H Millimetre . . . . one-thousandeth of a metre . 0*0393708 inch English. Reciprocally. French. The inch . . . . one-twelfth of a foot English 2*539954 centimetres II „ foot 3*0479449 decimetres i| ,, yard . 3 feet . . . . 0*91438348 metre ,, furlong . . 320 yards . . 201*16437 metres i ,, mile . 1 /60 yards . . 1609*3149 metres To reduce English measure into French, multiply by ; and to reduce French measures into English, divide by: I nches to centimetres . . 2*5400 Feet to metres . 0*304/945—practically 0*3048 Miles to kilometres . 1*6093 Feet square to metres square 0*09290 r A yard cube equals I 0*76458 metre cube | „ cube to metres cube . 0*028314 . . . . . 2 B 565 WET Centiare Are Hectare WEIGHTS, COMPARATIVE. WEI French. SURFACE. English. * ,■^ ass sf -*■“* a square< 100 A yard square The rod, or . ,, rood ,, acre Reciprocally. contains . • • perch square . • 1210 yards square 4840 do. do. 2 471143 acres 0-83697 m&tre square 25 291939 metres square 10*116775 ares 0-404671 hectare In round numbers, the hectare may be taken as equal to 24 acres French. Litre . Decalitre Hectolitre CAPACITY. English. a cube of one-tenth of a m&tre } 2*2009668 gallons { on a side ten litres . • one hundred litres English. Reciprocally. Pint Quart . Gallon Imperial Chaldron equal to 22009668 French. 0-567932 litre 1-135864 „ 4-54345794 litres 13-085166 hectolitres ^^^or^vldetby S W7*. of one cubic foot of the following substances : ,qo- Water.62-5 Air.0-075 486 A.AOfi 489- Steam. 0 036 29-5 Weight in Cast iron . Wrought iron Steel . • • Pine wood . Weight of a Superficial Foot of Plate or Sheet Iron. Thickness IVeight in 1 No. of the I Thickness in inches. in inches. pounds, v iire-gauge. X x 40- 1 12 35- 13 8 S % 30- 14 u 27-5 15 1 6 5, 25- 16 To i 8 . 9 22-5 17 » 20- 18 A 1 — 17*5 15- 19 20 5 12-5 21 1 6 12- 22 -^2 11- 23 i 10- 24 8 74 25 8-12 26 8 7*5 27 Tff 6-86 28 1 T4' ! 6-24 29 5-62 30 1 i 5- 1__ 566 WEI WEEDING. WEL Weight of Rod Iron 1 foot in length, of the following Dimensions. SQUARE IRON. ROUND IRO N. FLAT IRON. Inch. Pounds. Inch. Pounds. Inch. Pounds. i 0-2 1 4 014 JL 4 X 1 0-8 3 8 0-5 3 8 *0-4 3 8 1 1-3 i 0-8 1 U 07 1 2 1 1-7 f 1-3 f 1- f 1 2-1 3 T 39 f 1-5 3 ¥ 1 2-5 8 2-6 i 2- i 2 1-7 1 3-4 1 2-7 3 8 2 2-5 H 4-3 H 3-4 i 2 3-4 H 5-3 n 4-5 f 2 4-2 if 6*4 it 5- 3 * 2 5-1 H 7-6 H 6- 3 2-5 if 8-9 If 7- 3 8 3 3-8 1 3 A * 10-4 1 3 A * 8-1 1 2 3 51 1 3 11-9 1-Z. 1 8 9-3 f 3 6-3 2 13-5 2 10-6 3 ¥ 3 7 - 6 2f 171 13-5 4 3-4 2i 21-1 2* 16-7 3 8 4 51 2f 25-6 2f 201 1 2 4 6-8 3 30-4 3 23-9 f 4 8-4 41-4 H 32-5 t 4 101 4 54-1 4 42-5 5 4-2 5 84-5 5 66-8 3 ~5 5 6-3 6 121-7 6 95-6 i 5 8-4 7 165-6 7 130- f 5 10-6 8 216-3 8 169-9 3 5 12-7 Welding, the operation of combining or joining two pieces of iron or steel, by bringing the surface to be joined to a heat nearly equal to that of fusion. Well, in ship-building, a partition to enclose the pumps, from the bot¬ tom to the lower decks, to render them accessible, and prevent their taking damage. Wells. The practice of boring for water, adopted in the province of Artoise, in France, has given the denomination to those wells which are termed Artesian. Wells on this principle are very applicable in low level districts covered with alluvial deposit or clay; in such situations springs are seldom found, and water cannot be obtained by sinking an ordinary well, unless at a disproportionate cost. The east¬ ern part of Lincolnshire, which lies between the chalk range called the Wolds, and the sea, is a case in point. It was discovered, perhaps accidentally, in sinking through the clay to the subjacent chalk, that water rose to the surface in a perpetual fountain, and an am¬ ple supply was obtained over the whole of that district by the sim¬ ple operation of boring. A number of wells of this de¬ scription have also been executed in the neighbourhood of London by performing the London clay in¬ to the porous bed of the plastic clay formation, and into the chalk. The principle of operation is simply this. The hole is bored through impervious strata that do not contain water, into lower strata that are fully charged with it, and the water rises by hydrostatic pres¬ sure. The height to which it will 567 2 b 2 WEL WELL-SINKING. WEL rise obviously depends upon the in¬ clination of the strata, and other causes which affect the relative levels of the hole that is made, and the subterraneous body of water that has been tapped. Under most circumstances it is necessary to protect the perforation that is made by sinking iron pipes. The boring is thus secured against the accident of the sides falling in, and another advantage, which is of some importance, is obtained : it may chance that the object is to obtain a supply of soft water which has been ascertained to exist at a certain level, and that the strata which have to be pierced to get to it contain hard or impure water ; in such a case the boring would be continneddown to theproper depth, and the pipes being plunged into the soft water, it w ould rise through them, and any water or impurity which might be found in the strata through which they passed would be effectually excluded. If it so happened that at a certain depth below the soft water amineral water could be obtained, instead of going to the expense of a fresh bore from the -surface, it would only be necessary (supposing that both would flow to the same level) to bore through the pipes already fixed, to the mineral water, and insert smaller pipes within the larger ones, for bringing it up to the surface. The history of the great Artesian well which was completed at Gre- nelle is one of the most remark¬ able instances of confidence in the principle, and of perseverance in execution, that is on record. The facts are believed to be substantially as follows :—A person suggested to the authorities, that an Artesian well would supply water in a situa¬ tion where it was greatly required ; and after some discussion it ended in his undertaking the work on the stipulation, “ No water, no pay.” He bored down far beyond 568 the point at which he expected to have terminated his labours ; but no signs of water appeared : he persevered, however, till he found that the expenses had ruined him. Under these circumstance, he consulted the celebrated Arago, who encouraged him to proceed. Again he went to work, and after unparalleled difficulties, at the ex¬ piration of six years, and at the depth of 1800 feet, the superin¬ cumbent mass was bored through, and the water came boiling up in such quantities, and with such force, as to flood the whole district. The water, when first obtained, was extremely foul: the partial in¬ troduction of an Indian-rubber hose is said to have remedied this, and the water thus procured from the main spring was quite pure, and at a very high temperature. Well-sinking. The process of boring may be thus briefly described : The auger, the chisel, or any of the great variety of implements j which are required to meet differ¬ ent circumstances and overcome the numerous difficulties which are experienced, are screwed to iron rods, which are usually from 2 to 2% inches square. The first rod which is attached to the tool is generally about 6 feet long, and the others are of the uniform length of 20 feet. Each rod has a screw at one end, and a tapped socket to receive a screw at i the other, and they fit universally; ; there is also a ‘ middle knob ’ in li the centre of each rod, which is used for suspending the rods al¬ ready fixed, whilst others are being ! added or detached, as the imple¬ ment is lowered into the bore, or drawn out of it. In commencing operations, a stage about 8 or 10 feet square, and 20 feet high, is erected, when the boring takes place from the surface. The men who work the tool stand upon this stage, and a windlass or crab is fixed, chiefly WEL WHARF. WHA for hoisting and lowering the rods, but mechanical power is also re¬ quired for assisting in the working when the depth is very great. A boring handle is attached to the rod, which is used for turning the tool round in boring with an auger, or in ‘jumping,’ as is re¬ quired when cutting through rock or indurated clay with the chisel. When the boring has proceeded till it is found difficult to turn the rods, or at such times as practical experience dictates, it is necessary to draw out the implements and to bring up the loose’material that may be at the bottom of the bore. Under ordinary circumstances a common windlass, or a small crab, gives sufficient power to work, hoist, and lower the rods; but when the bore is of great depth, or the instruments of unusual size, an increase of mechanical power is ne¬ cessary. This may be conveniently obtained by placing a second crab on another stage ; or, in extraordi¬ nary cases, horses may be applied on the surface. An economical mode of boring has been adopted with success on some parts of the Continent by using a heavy cast-iron bar, 2 cwt. or more, armed with a chisel at the lower end, and surrounded by a cylinder or hollow chamber, which receives through valves and brings up the detritus of the per¬ forated stratum. This implement is suspended over a wheel or pulley fixed above the spot in which the hole is made, and is raised up and let fall by manual labour. As the rope is raised up and down, its tortion gives the chisel a circular motion, which varies the place of cutting at each descent. When the chamber is full, the whole apparatus is raised quickly to the surface, and the material it contains discharged. In cutting through a hard stra¬ tum, or under circumstances where iron pipes could be dispened with, this plan of boring a hole would doubtless answer; bnt it is con¬ ceived that the bore could scarcely be made sufficiently straight to ad¬ mit of pipes being inserted. It is, however, a much less costly me¬ thod of executing the work where it can be made to apply, and is well worth attention. Well-staircase, a winding staircase of ascent, or descent, to different parts of a building, so called from the walls enclosing it resembling a well, called frequently a geometri¬ cal staircase. Wen Id, or Weald (Saxon), a forest. Wharf, a levelled surface, terrace, or embankment, formed on a river or canal bank, or sea-coast, to facili¬ tate the landing and embarkation of persons and goods, and protected by an artificial frontage or struc¬ ture of masonry or other materials. The natural form of banks and coasts, unless defined by masses of rock, is usually shelving or inclined, so that the depth of water is gra¬ dually reduced, and thus prevents the close approach of floating ves¬ sels. By the construction of wharf- walls, which are either extended into the deep water, or the founda¬ tions of which are sunk so as to permit of the subsequent removal of the bank, and thus bring deep water into contact with them, ves¬ sels areenabledto comeclose along¬ side, and thus discharge or receive their cargoes directly from the wharf. Wharf-wallsare constructed of various materials, but are always formed with a slope or batter out¬ wards towards the base, in order to give greater stability to them, and to resist the action of the tide and the waves. Much theory has been expended in attempts to determine the precise forms which should be given to these structures, and, ac¬ cordingly, some engineers approve of plane-faced walls, while others prefer curved faces; and another theory has been started to explain that a perfectly vertical face is the 569 WHE WHEEL AND AXLE. WHA best of all adapted to resist the in¬ fluence of waves. Whether this position be theoretically correct or not, however, the value of an ex¬ tended base, in giving stability, is too well known to need demonstra¬ tion, and derives support from that intuitive kind of feeling which pro¬ ceeds directly from the evidence of our senses. Adopting the inclined plane face as a good practical one for wharf-walls, the rate of inclina¬ tion or hatter may be determined from 1 in 8 to 1 in 12, that is, with a total divergence from the perpen¬ dicular of £ or jLof the total height, being from 1 to H inch, in a foot. The front of the wall, if of masonry, may be protected by a row of sheet¬ piling, either of timber or iron. Tn the former case, the piles are driven close together, and bound along the top with a horizontal tie or waling firmly bolted to the piles. If iron piling is used, the piles are driven at intervals of from three to five feet, and cast-iron plates fitted in between them, being se¬ cured within grooves formed in the sides of the piles. The Brunswick Wharf, at Blackwall, affords a good example of this description of piling. The masonry of the wall is founded upon the piling, the length and closeness of the piles being determined with reference to the nature of the subsoil, and the whole of them are driven to a firm bottom and levelled on the heads, being strongly secured in their po¬ sition by means of longitudinal and transverse ties or beams, on which the firstcourse of footings was built. The durability of these walls is known to depend greatly upon the kind of mortar or cement used in connecting the masonry or brick¬ work. Cements known as water- cements, formed with lime which has the property of hardening un¬ der water, should be preferred to all others. The thickness of the wall must depend upon its height and the nature of the materials be¬ hind it. If these are likely to press severely against the wall, such as clays liable to hold great quantities of water, etc., the thickness of the wall will be required to be greater than if gravel, or other non-reten- tive material, forms the backing. Strong ties of iron should in all cases be secured to the front of the wall, passing through it, and being secured by plates and keys in the front, and extending backward to a considerable distance, and se¬ cured to a row of piling driven into the solid ground. These land-ties will also considerably assist the wall in resisting the forward pres¬ sure of the soil behind it. Imme¬ diately at the back of the wall a firm body of concrete, or at least well-puddled clay, should be in¬ troduced. Whichever of these is used as a hacking, it should be consolidated as much as possible, and it will thus resist the admission of moisture behind the wall which is indispensable to secure its per¬ manent durability. The concrete should he cast in from a height above its intended position, and allowed to set before it is filled in; and if clay be substituted, it should be thoroughly well rammed in, and made as solid as possible. Wheal. The ancient Cornish called a mine huel, which has been cor¬ rupted into wheal. Wheel and axle. This machine is so named by reason of its consisting of a wheel and cylinders, having a common axis with pivots fixed in its extremities, on which the whole may revolve. This very simple and useful contrivance, although usual¬ ly designated a second mechanical power, requires the consideration of no other principles than those adduced for the lever ; it is nothing but a lever, having the radius of the wheel for one arm, and that of the cylinder or axle for the other, the fulcrum being the common centre of both. This machine is also termed the ‘ Perpetual Levert 570 WHE WHEEL-CUTTING MACHINE Will for since the power and the resist¬ ance operate respectively at the circumference of a circle revolving about an axis, it is obvious that the rotation must maintain the continuity. Wheels, in locomotive engines: the well - known invention for ob¬ taining a rolling progressive mo¬ tion. They receive names corre¬ sponding to the part of the engine or tender they support; as leading, trailing, etc. Driving wheels vary in size from 4 feet 6 inches up to 10 feet diameter. Leading and trailing wheels vary from 3 feet up to 4 feet 6 inches in diameter. Tender wheels are usually about the same size as the leading and trailing wheels of the engines they are attached to. Wheel-cutting machine, a machine for cutting out the teeth of wheels. The most perfect machines for shaping the teeth of wheels are those invented by Mr. Lewis, of Manchester, which are adapted for cutting the teeth of spur, bevel, and worm wheels, of either metal or wood. The principal working parts of these machines and the mode of action is as follows : Two side-frames have angular ridges from end to end, to fit into corresponding grooves in the bot¬ tom of a travelling frame: this frame can be adjusted by a screw moved by a hand-wheel at the back of the machine : at the front of the machine is a strong spindle, placed vertically, to carry Ihe work which is fixed on the top of it, and at the lower part is a large worm- wheel moved by a screw, to which is connected a train of three wheels: the sizes of the first and third wheels must be such that half a revolution of a handle, which falls into a notch after each half-revo¬ lution, shall turn the work so that any point in the pitch-line of it will move through a distance equal to the pitch. To the travelling frame a slide is attached by holts and joints, in such manner that it may be fastened to act vertically, or at an angle in the direction either of the length or breadth of the machine. The cutter, and its wheels for diminishing the speed and pulley for communicating mo¬ tion to it, are carried by the slide. The cutter is a circular piece of steel notched like a saw, and shaped to fit the spaces between the teeth of the wheel, and is raised or low¬ ered by a rack at the back of the slide, worked by a pinion and han¬ dle. The travelling frame and slide being adjusted to the work, and the suitable wheels arranged for turning it the given distance, the machine is set in motion and the revolvingcutter pressed down upon the rim of the wheel by the handle and rack till the space has been cut; the cutter is then raised, and by giving half a revolution to the handle attached to the worm-wheel apparatus, the spindle and work are turned so that the latter is in pro¬ per position for the cutter to act again. For a spur-wheel the slide acts vertically, for a bevel-wheel it acts at the requisite angle in the direction of the length, and for a worm-wheel at an angle in the direction of the breadth of the machine. Whim, a machine used for raising ores, etc., worked by horses, steam, or water. Whim-shaft, in mining, the shaft by which the stuff is drawn out of the mine by the horse or steam whim. Whispering gallery , a curvilinear cor¬ ridor or balcony within the cupola of St. Paul’s cathedral, London, and in other ecclesiastical build¬ ings. White Chalk is a well-known native carbonate of lime, used by the artist only as a crayon, or for tracing his designs; for which pur- pose it is sawed into lengths suited to the port-crayon. White crayons and tracing chalks, to be good, must work and cut free from grit. From 571 WIC WILKIE. WIL this material both whiting and lime are prepared, and are the bases of many common pigments and co¬ lours used in distempering, paper- staining, etc. Wicker-work, at an early date, was occasionally employed for the roof¬ ing, if not for the entire construc¬ tion, of churches. Wicket, a small gate or door within, or a part of a massive or larger door or gate for the passage of pedestrians. Wilkie (Sir David). The works of the late Sir David Wilkie left by him at his decease cons sted of water¬ colour drawings, portfolios of studies and sketches, sketches in oil colours and incomplete pictures. There were many works finished: nearly all of them were works done when from home : some in Ireland, some in Spain, most on his journey to the Holy Land. They are proofs of unremitting industry; nothing escaped him, all that met his eye formed subjects for his pencil,— whether a distant landscape, a pipe or a sword, an eastern street, a girl at a window, Mehemet Ali, or a scene near the birthplace of Ho¬ mer. Proofs indeed these works are of his practice being a work of love; it cannot but be supposed that all this labour must have been the occupation of his leisure hours as well as his working hours. Well might Sir Robert Peel, at the meeting for erecting a monument to Wilkie, bring into notice such untiring industry. Anything of the slightest interest was committed to paper. Numbers of the subjects would not form finished pictures, nor enter into the composition of pictures, though possibly any might be subservient for such pur¬ pose; but seemingly without look¬ ing forward to any further use, he committed everything to canvas, or rather to paper. Similarly may it be said of Wilkie in his art; he reduced to design whatever entered his eye, and design came to him by nature spontaneously. The collec¬ tion also contained a number of the works of Fuseli. Fuseli and Wilkie, what a contrast! The one all imagi¬ nation, the other all reality. Sin and Death, A Griffin pursuing an Arimaspian, The Nightmare(sketch for), Macbeth and the Witches, The Walpurgis Night, were some of the subjects Fuseli had selected. Wilkie’s practice does not appear uniformly the same; he varies much in the materials of his studies and sketches. There is a distinction to be remembered between works executed at home and abroad. The facilities in the one case and the difficulties in the other, lead to se¬ lecting different materials. There is one,‘A Village School:’ the heads and figures are all put in with their expressions, but not finished. Colour is also put in, but unfinished in the back and foreground; the canvas is covered, or rather the panel, for though it is, I should say, the size j of a half-length, the painting is on I a panel, and the ground pure white. There is much humour in the Do¬ minie, and in the several groups. There is a right good spirit about it, that shows how at home Wilkie was in the subject. For such ex¬ cellence people don’t like to receive his other works. There is much to be said on this question. His works are evidences of the great care and neatness of hand in the progress of his pictures. There is nothing to undo or to amend, and only the part that he intends to finish appears touched. There is no experimental uncertain paint¬ ing put in one day to be expunged another. Wilkie advised Haydon to use dark background colours with economy in an early stage, and he practises his precept, though he puts in freely a dark that in chiaroscuro is to stand as such. The other picture is ‘ Knox ad¬ ministering the Sacrament:’ this too is upon panel, the ground pure white. The heads more—perhaps 572 WIL WILKIE. quite finished. It is less in size; beside it, is a small rough sketch upon paper of the principal figures ; the others are uncertain. There is also a smaller sketch in oil made with great precision, the surround¬ ing groups still not the same as ap¬ pear in the picture. There is too a study in black chaik of Knox, and two of the principal heads very carefully and effectually drawn. The heads are probably painted from these with nature present as a guide. It appears that Wilkie must have made use of his stu¬ dies and sketches for painting from, because, as in this instance, if he used nature this highly finished chalk study would be useless. Haydon remarked what a strange practice Wilkie had observed in the Knox. On a milk-white panel hehadpaintedintheheadsand half¬ figures into a glaze of asphaltum as it appeared, the MacGuelp just tinged. No other part of the pic¬ ture was worked upon, a few slight pencil lines only indicating the lower part of the figures in the foreground. The leading part of the picture reminded one of Da Vinci’s ‘ Last Supper.’ The back¬ ground, which was untouched and for which I saw no arrangement in any sketch, was staring him in the face during the time of completing the heads, and from its pure white¬ ness blinding him while painting. In effect too it was injuring the finished parts, which had a yellow glaze which looked sickly. There is something of this unpleasrng effect constantly about Wilkie’s painting. It is not from painting into a glaze, I think, that this oc¬ curs, but from passing a glaze over finished work, for there was a por¬ tion of the armour in the upper portion of one figure which was free from this stain. The white background could not be for a key; it was very dazzling and disa¬ greeable next the finished work. There was one hand left, I suppose, WIL in dead colouring, for it was quite pallid, though it had a finished look, like being worked up in brown and white. Haydon said, “Oh ! but the next thing he’d go over the back¬ ground with colour;” and there was more probability, I think, of his completing the figures before such process. Haydon commended highly W T ilkie’s mode in ‘ The School ’ of getting in the subject: this is what I have before men¬ tioned and admired. There is much cautious treatment, like the process in water-colours. It has more of the neatness and precision of the Dutch masters than the im- pasto of the Italian. In the cata¬ logue of his effects connected with ‘The School,’ the following. It is to be remembered there are 36 figures in the composition. No. 84, Study (in chalk) for ‘ The School.’ 150, ‘Hedge School:’ this probably might suggest the work. 183,‘ The School,’ group of hands. 184, Do. 185, Do.. 186, Do. two studies. 303, Sketch (chalk) for ‘ The School.’ 304, Do. 385,‘The Schoolmaster.’ 318, Study for the School. 319,Do. Study of hands and a head for the School. ‘The School’ brought 720 guineas, and was bought by Moon. For the Knox picture the following are in the catalogue:— 60. ‘ John Knox administering the Sacrament,’ in pen and ink, slightly washed. 191. ‘ John Knox administering the Sacra¬ ment.’ 245. ‘ Knox presenting the Cup,’ study of hands,. 246. Do., two hands. 247. Do., gauntlets. 218. Do., with the cup and a lady : from same. 249. Do., preaching, and one other. ‘ The Letter Writer’ sold, price 425 guineas. ‘ The Tartar relating the Capture of Acre’ sold for only 175 guineas. Both very unfinished, the latter most so. ‘ The Letter Writer’ was very effective and very pretty. It represents a girl con¬ sulting a letter-writer in the streets of Constantinople : a female head 2 b 3 WIL WILKIE. WIL in the foreground forms the group. The old Turk has his pipe, and an old chest beside him, containing his writing materials, I suppose; a dog lies in one corner. Painted upon panel. In the catalogue w'as found 446. First sketch of the ‘ Letter Writer,’ a tinted drawing ; the colouring was very little. This, I think, was probably the the first—whether taken on the spot, or immediately on reach¬ ing home, is doubtful. There is another sketch at the Royal Aca¬ demy which may be for the ar¬ rangement of colour : some parts are in pencil, some in red chalk, and water colour. From this pro¬ bably the oil painting was taken. 580. Study of an old chest. This I did not see, but probably this may be for the ‘ Letter Writer.’ Examples of Eastern costume Wilkie brought with him. A male and female lay figure were dressed in them. From Spain too he brought some. Haydon bid for a Spanish cloak. 488. ‘ Bargain¬ ing for a Circassian Slave,’ a tinted drawing. In this sketch, or rather composition, I recognized the figure of the Circassian slave as that of one who before passed as 462. J A Circassian Lady.’ In this way Wilkie may have made figures do duty frequently. ‘ The Tartar relating the capture of Acre’ may have been composed in this way. It is of great interest to trace the history of a great man’s works. With this view I examined Wilkie’s sketches to trace their history if possible, and his practice. In this way he may have composed the last-mentioned picture. There was his picture of ‘ Chelsea Pensioners listening to the News of the Battle of Waterloo,’ to suggest the sub¬ ject ; and a great sensation at the time was created by the siege of Acre. Several views of the place he had himself taken. In the East particularly such an event as the siege would form a subject of conversation for the common people; and without seeing the incident he represents there is enough in the following sketches to make up the picture. 447. ‘A Barber’s Shop, Constantinople.’ I mention this, because in the pic¬ ture is a sketch of a barber shaving a man, with the basin up to his neck. The metal basin is placed with the outside next the throat. It always reminds one of Mam- brino’s helmet. 482. A ‘ Turkish Coffee House.’ 487. ‘ A Coffee Shop.’ 483. ‘ Interior of a Cafe.’ From recollection I should say that 444, ‘ A Post Rider,’ a capital finished sketch, was very like the Tartar relating the news, and per¬ haps was the man, some of their equipments were the same—the position was different. 589 is ‘ The travelling Tartar, or the Queen’s Messenger.’ The scene appears in a Turkish coffee-house, where the company are seated, smoking, eat¬ ing, drinking, being shaved, while the Tartar is relating the news. Referring again to nature. In works possessing such truth and nature as Wilkie’s, a figure can never successfully be turned to a particular use without such being originally in contemplation of the artist. And again, in composition, a figure borrowed from a sketch will not compose without altera¬ tion, and with alteration you want nature. Painting from studies that are sketches with design and light shade, where they are taken for one certain intention, and have merely to be copied in colours on canvas, can readily be understood. William of Wykeham. History has only taken care of the fame of one of our early Gothic artists,—the architect of Winchester Cathedral, Windsor Castle, and New College, Oxford. He was born 1324, the eighteenth of Edward II. Of Windsor Castle little remains of Wykeham’s workmanship, save the Round Tower. 574 WIL WINCH AND AXLE. WIN Willow wood is of many varieties : it is perhaps the softest and lightest of English woods; it is planed into chips, and used for many simple purposes. Wilson (Richard) was born 1713, in Montgomeryshire. At first he pur¬ sued portrait painting, but in his thirty-sixth year, on going to Italy, relinquished that department of art for landscape painting. He found no market for his productions, gradually fell into distress, and was rescued from utter starvation by the salary of librarian of the Royal Academy, Finally he suc¬ ceeded to a small estate in Wales, which was sufficient for his com¬ forts, and where he died. Wil¬ son’s landscapes are in general productions of fancy, rather than of existing reality-—scenes pictured forth by the imagination, rather than transcribed from Nature,-— yet there is enough of nature in them to please, and enough of what is poetic, to charm the most fastidious fancy. He sometimes painted fac-similes of scenes. Wimple, a plaited linen cloth which nuns wear about their necks; also a flag or streamer. Winch or Wince, in raining, the wheel or axle frequently used to draw water, etc. in a kibble by a rope. Winch and Axle , a machine consti¬ tuting a small windlass, and con¬ sisting of a cylinder of wood which is capable of turning on its axis between two upright posts of the same material, or between the ends of a cast-iron frame; a lever at one or at each extremity of the cylinder is attached to an iron axle passing through the latter at right angles to its direction, and is fur¬ nished with a handle, which is parallel to that axle. The name winch is given to a lever or handle of this kind, and the word is sup¬ posed to be derived from the verb guincher, signifying, in old French, to turn, or bend in a curvilinear manner. The machine is used to raise a weight vertically, or to draw an object towards it; for which purposes the object is con¬ nected with it by a rope or chain which continually passes over the curved surface of the cylinder as the latter is made to turn on its axis by a man acting at the handle. Since the cylinder revolves once while the handle, or the extremity of the lever to which it is attached, is made to describe the circumfer- rence of a circle, it is evident that the mechanical power of the ma¬ chine is precisely that of the wheel and axle. When of a simple form, it is employed to raise water from a well, and earth or some other material from the shaft of a small mine; and one of a complex na¬ ture is used, by means of a crane, to raise casks or heavy packages from the ground to the upper part of a building. When great weights are to be raised, the machine is usually fixed in a frame of cast iron, which is rectangular o« the plan, but its extremities or faces have the form of a triangle, or of the letter A. The axle of the cylinder is sup¬ ported on a horizontal bar at the middle of each end of the frame, J and to the cylinder is attached a j toothed wheel which turns with it on the .coromoa axis; above this j wheel, and par,ailed to the cylinder, 1 is an iron axle which carries a pinion with teeth working in those of the wheel, and causing the latter | to revolve, the pinion itself being turned by means ,of the lever and j handle at one or at .each extremity of the frame. A machine of this kind is called a crab ; and when a weight is to be drawn horizontally or raised above the cylinder, the machine must of course be bolted to the floor or firmly fixed in the ground, in order to prevent it from being moved from its place. In such machines there is generally, at one extremity of the cylinder, a wheel having on its circumference 575 WIND. WIN WIN teeth like those of a saw; and a click or catch, which turns freely on a pin, is attached by that pin to the side of the frame in such a manner that it may fall between the teeth. By this contrivance, if the handle should break, or the moving power be taken off while the weight is suspended in the air, the latter is prevented from de¬ scending. Machines of this kind are occa¬ sionally constructed, which have the power of holding the weight in any part of its ascent or descent without a ratched-wheel and catch. The only disadvantage attending the machine, when compared with an ordinary winch or capstain, is, that it requires a much greater quantity of rope to raise or move the object through any given dis¬ tance. It was first proposed in Europe by Mr. George Eckhardt, but machines of a like kind have, it is said, long been in use in the East. The winch is employed in the common jack, which is used to lift great weights, or to move them through small distances. The handle turns a pinion with teeth, which act on others at the circum¬ ference of a small wheel; and on the axle of this is a pinion with teeth, which work in those of a rack-rod. The axles of the wheel and pinions being let into the sides of a case of wood or iron, the re¬ volution of the wheel produces a rectilinear motion of the rack; and one end of the case beingfixed to the ground, or against an immovable object, the extremity of the rack at the opposite end forces forward the body which is to be displaced. Sometimes, instead of a rack, the machine is furnished with a wheel whose axle is hollow, and cut in the form of a concave screw: within this screw is one of the convex kind, which by the revolution of the wheel and its axle is made to move in the direction of the latter, and thus to press before it the ob¬ ject which is to be removed. This machine has, however, consider¬ able friction. The force exerted by a man in turning a winch vertically, varies according to the position of the lever with respect to the horizon. When the lever, or that part which is perpendicular to the axle, is per¬ pendicular to the ground, and the handle is at the highest or lowest part of the circle described by the end of the lever, the man either pushes the handle directly from him or pulls it directly towards him ; and in each case he exerts a power which is estimated at 27 or 30 lbs.; but when the lever is in a horizontal position, the man eithers throws a great portion of his weight on the handle to press it down, or he exerts his muscular force in a direct manner to pull it upwards ; and the force exerted in these positions is estimated at 140 or 160 pounds. The force exerted must very evidently have different values between these quantities in other positions of the winch; and the practice is to cause two men to work at the same time to turn the machine, one being at each extremity of the axle of the cylin¬ der. The levers of the two winches are placed at right angles to one another; consequently, when one man is pushing or pulling horizon¬ tally, the other is pressing or pull¬ ing vertically, and thus the opera¬ tion of turning goes on with nearly uniform intensity; the first man working in the least favourable position when the other is working in that which is most so. Wind, instrument for measuring the force and velocity of: a fly (re¬ sembling thatof a revolvingventila- tor, or the sails of a wind-mill) is fixed to the small end of the vane of a weathercock so as to be turned with its circular disc to the wind; and it consequently revolves by the action of the wind with a rapidity 576 WIN WINDOWS. WIN increasing as the force of the wind increases. The revolutions of the axis of this fly are converted hy a train of toothed wheels and screws into a vertical motion, by which a pencil is carried downwards, touch¬ ing the surface of a vertical cylin¬ der the cylinder having the axis- of the weathercock for its axis. As the vertical rod “bn which the pencil slides is attached to the vane of the weathercock, the point of the compass from which the wind blows is recorded on the sides of the cylinder on which the mark is made; while the quantity of the wind is represented by the extent of the descent of the pencil. Wind beam, in ancient carpentry, a cross-beam used in the principals of many ancient roofs, occupying the situation of the collar in mo¬ dern king-post roofs. Winding, in ships, twisting on an uneven surface. Winding engines. In winding engines for drawing coals from a pit, where a given number of strokes are re¬ quired in drawing a corf, the dia¬ meter of the roll at the first lift must be ascertained. In this case the engine is supposed to have flat ropes, such as are generally used, and which lie upon each other. To find the diameter of a rope-roll at the first lift, it is necessary to know the depth of the pit, the thickness of the rope, and the number of strokes which the en¬ gine is intended to make in draw¬ ing up a corf or curves ; then, the thickness of the rope being known and the number of strokes, the thickness of the ropes upon the roll can be determined, let the dia¬ meter of the roll be what it may. Suppose the thickness of the rope to be 1 inch, and the number of strokes 10 ; then the radius of the roll is increased 10 inches, or the diameter is increased 20 inches, whatever the diameter may be. Windlass, in mechanics, a machine by which a rope or lace is wrapped 5,77 round a cylinder: in navigation, a horizontal machine of strong tim¬ ber, used in merchant ships for heaving up the anchor, instead of a capstan. Wind-mill, a mill which derives its motive power from the impulse of the wind. The building contain¬ ing the mill-work is usually lofty, and placed on elevated ground. The machinery consists of a shaft, upon one extremity of which arms radiate at right angles, similarly to the spokes of a wheel: upon these, vanes or sails are set at a small angle (about 22°). By this means the wind, blowing directly upon the area occupied by the vanes, acts obliquely upon the whole of them, causing them all to move in a direction transversely to that of the wind. Suitable means are provided for bringing the sails into a position to confront the current of the wind. The motion of the sails is transferred by gearing to any machinery required to be driven, which is most commonly mills for grinding corn. Wind¬ mills were formerly extensively employed, in Holland, to give mo¬ tion to pumps for the drainage of land. The power of the wind is uncertain and variable in its inten¬ sity, and its application as a prime mover for mechanical purposes is consequently limited. Windows were almost unknown in the religious and other monumental structures of the Egyptians, Greeks, and Romans, but they constitute an essential and distinguishing feature of the Gothic, to which style they stand in the same rela¬ tion as Orders do to the temple architecture of antiquity. Windows admit of very rich and varied decoration, and those in Beccles church, Suffolk (repre¬ sented on the opposite page), are beautiful examples. The varied exuberance of fancy displayed in the tracery may possibly be ac¬ counted for by supposing each to 578 WIN WOOD. WOO have been the gift of some pious in¬ dividual, who, while he perpetu¬ ated his munificence, marked also his taste and ingenuity. The practice of window tracery everywhere had its origin in win- dow -grouping, placing two or three lancet windows beside each other, and one or more foil or rosette windows above and between their heads, in order to fill out the arched cell of the vaulting, which then necessarily gave the whole group an arched outline; and this was indicated by a general drip- mould or label. It then became desirable to lighten the irregular shaped masses of stone left between the perforations, and this was done by piercing these masses, or span- drils, and reducing the solid frame of each foil or rosette to an equal thickness all round, as if several such frames or rings were packed into one great arched opening, which henceforth was regarded as one window instead of several. (For further illustration, see art. Tracery.) Wind-sail, in navigation, a sort of ventilator, consisting of a wide tube of canvas shaped like a fun¬ nel, to convey a stream of fresh air downwards to the hold and lower deck of a ship. Wing transon, in ships, the upper¬ most transon of the stern-frame Winze, in mining, a sinking in a lode communicating with one level, for proving the lode or ventilating the drivings. Wipers, the cogs of a horizontal wheel. Wood, in its raw state, contains a large amount of water. This water contains more or less soluble mine¬ rals, and is called sap. By drying wood, a great part, but not all, of this water is evaporated. If wood is dried in a closed vessel, and then exposed to the atmosphere, it quickly absorbs moisture; but the moisture thus absorbed is much less than the wood originally con¬ tained. The amount of water varies in different kinds of wood, and also varies according to the season. Wood cut in the month of April contains from 10 to 20 per cent, more water than that cut in the month of January. The following Table shows the percentage of water in different kinds of wood dried as far as possible in the air:— Beech.18-6 Poplar.260 Sugar and common Maple 27 - 0 Ash.28-0 Birch.30’0 Oak, red.34 - 7 Oak, white.35 5 Pine, white.37‘0 Chestnut.38 - 2 Pine, red.39’0 Pine, white.45-5 Linden.471 Poplar, Italian .... 48-2 Poplar, black . . . . 51 - 8 Wood cut during the months of December and January is not only more solid, but it will dry faster than at any other period of the year, because the sap by that time has incorporated a great part of its soluble matter with the woody fibre ; what remains is merely wa¬ ter. When the sap, during the months of February, March, and April, rises, it partly dissolves the woody fibre ; and the drying of the wood is not only retarded, but the wood is weakened, in consequence of the solid matter thus held in solution. The difference in chemical com¬ position of the woody fire, in most kinds of wood, is but slight, as the following analytical Table shows:— Hy- Oxy- Carbon drogen. gen. Sugar Maple 52 - 65 5-25 42-10 Oak . . . 49-43 6 07 44'50 Poplar, black 49 - 70 6 - 31 43'99 Pine . . . 50 11 6-31 43'58 579 woo WREN. WRO Wood is generally bought by admeasurement, and its specific gravity is directly in proportion to its amount of carbon, hydrogen, and oxygen. The following Table shows the specific gravity of wood. Water =1000:— Green. Air-dried. Oak, white . . 1-0754 0-7075 Oak, red . . 1-0494 0-6777 Poplar . . . 0-9859 0-4873 Beech . . . 0-9822 0-5907 Sugar Maple 0-9036 0-6440 Birch . . . 0-9012 0-6274 Pine, red . . 0-9121 0-5502 Pine white . . 0-8699 0-4716 Ebony . . . 99 1-2260 Guaiac (lignum ' ► 99 1-3420 vitae . . . / ” Woolf’s engine, a steam-engine so called from its inventor’s name, with two combined cylinders of dif¬ ferent diameter, the eduction pas¬ sage of the smaller cylinder com¬ municating with the steam passages of the other; high-pressure steam being used in the small cylinder, and made to act expansively in the large one, the steam being after¬ wards condensed in the usual manner. By this arrangement steam is economized, and a con¬ siderable saving of fuel is effected. Work, in mining, ores before they are cleaned and dressed. Working big, in mining, signifies sufficiently large for a man to work in. Working drawings consist of plans, elevations, sections, and details in full, of the whole, and of all the parts of an edifice, to as large a scale as may be found convenient; generally made in outline, except¬ ing the sectional parts, which are mostly shadowed, in order to make them more obvious to the work¬ man, for whose use these drawings are made. Worm-wheel, a wheel having teeth formed to fit into the spiral spaces of a screw, so that the wheel may be turned by the screw. Wreath, in heraldry, that which is between the mantle and the crest, called also a torce; also a boar’s tail, so termed among hunters. Wren (SirChristopher), born in 1631 or 1632. The Monument, by Wren, was begun 1671, and com¬ pleted 1677. It is of the Doric order, rises from the pavement 202 feet. The plinth is 21 feet square, and ornamented with sculpture by Cibber, representing the flames subsiding on the appearance of King Charles; beneath his horse’s feet a figure, meant to personify religious malice, crawls out, vomit¬ ing fire. The shaft is 15 feet in diameter at the base. The Royal Exchange of London, and Temple Bar, were among his earliest works. St. Paul’s was his great work. The Church of SJ. Peter’s, at Rome, had twelve architects, and took 145 years to build; that of St. Paul’s was built in thirty- six years, and had but one archi¬ tect. On the artists of the Roman fabric honours and wealth were showered; on the architect of St. Paul’s the king bestowed £200 per annum, and the clerical and lay commissioners harassed him with criticisms, and persecuted him with ridiculous and ground¬ less charges. To describe all Wren’s churches would require volumes at least. The church of St. Mary-le-Bow, Cheapside, has been praised for the incomoarable beauty of its spire. The church of St. Stephen’s, Walbrook, is reckoned by many the masterpiece of the architect. The church of St. Bride’s, Fleet Street, is worthy of being named after that of St. Stephen’s, and the many churches in the city of London, St. James’s, Westminster, show the greatness of his mind. Wrought iron. The chemical differ¬ ence between cast iron and wrought iron consists principally in the de¬ gree in which foreign matters is present in each ; which is in larger amount in the former than in the 580 WRO WROUGHT IRON. WRO latter, this rule is applicable only to a given cast iron, and to the wrought or bar iron which is made from it. There are many cases in which wrought iron contains a larger amount of impurities than cast iron, and still continues mal¬ leable ; while cast iron of the same composition may be very hard and brittle. Berzelius detected 18 per cent, of silex in a certain kind of bar iron, which was still mallea¬ ble and useful. One-tenth of that amount of silex will make cast iron brittle. The foreign matters gene¬ rally combined with pig iron are, carbon, silicon, silex, sulphur, phos¬ phorus, arsenic, zinc, manganese, titanium, chrome, aluminium, mag¬ nesium, and calcium. Each of these tends to make iron brittle ; there¬ fore, in converting cast into wrought iron, it is necessary, as far as possible, to remove them. The main ditference between pig and wrought iron consists in their mechanical structure, or aggregate form. Pig iron is a homogeneous mixture of impurities and metal. Wrought or bar iron is a mixture of iron more or less pure with a mass of homogeneous impurities, or cinder, the latter filling the cre¬ vices between the crystals of the iron. Iron being fusible in pro¬ portion to the carbon it contains, if pig metal is melted, and the cin¬ der surrounding it exposed to the atmosphere, the carbon will be volatilized in the form of carbonic acid, and iron of greater or less purity will remain. To keep this iron liquid, a higher temperature is required: unless the temperature is raised, it will crystallize. In this state of metamorphosis its infusi¬ bility will increase, and after the expulsion of the carbon, it will contract into a solid mass in oppo¬ sition to the highest possible heat. By stirring and mixing the pasty iron, small crystals are formed; at first, on account of the partial fusion of the iron, in small parti¬ cles ; but, as the fusibility dimi¬ nishes, these particles unite by the force of cohesion ; and the bodies thus formed may, by exposure to a higher heat, be welded together. The mixing of cinder and iron will prevent the latter from forming large crystals: this result, of course, will be more easily prevented by diligent than by tardy manipula¬ tion. Where the pig iron is of such a nature as to keep liquid while the work goes on slowly, still bet¬ ter results will be obtained. This process is analogous to that of salt boiling, in which, by stirring the brine, the formation of large crys¬ tals is prevented. If the crystals of iron thus formed cohere, they produce under the influence of motion, a porous, spongy mass, whose crevices are, if not filled, at least coated, with cinder. If these masses, which are the loups or balls at the puddling furnaces, are shin¬ gled or squeezed, the crystals of iron will not unite, but form coated cells with a film of cinder, of greater or less thickness, according to the fusibility of the cinder. Iron in a connected form and cinder in sepa¬ rate cells, are thus blended in one homogeneous mass. The more this iron is stretched, the more it forms fibres. Fibrous bar iron resembles hickory wood, in being a combina¬ tion of fibres and spaces. In bar iron, these spaces are filled with cinder. When other circumstances are equal, the strength of the iron will be proportional to the fineness of the fibres. That portion of the iron which is not melted, which crystallizes too fast, or whose pre¬ mature crystallization cannot be prevented, is in the condition of cast metal, and cannot be con¬ verted into fibrous wrought iron. In the puddling furnace it is neces¬ sary to prevent crystallization by manual labour. If the characteristic between wrought and pig iron consists only in a well-regulated mechanical mix- 581 WROUGHT IRON. WRO ture of cinder andiron, fibrous iron should be producible from any cast iron, whether purified or not: this is actually the case. Very fibrous bar iron, which is strong and mal¬ leable, is made from very inferior cast metal, from which no impurity has been removed. At Hyanges, in France, very inferior metal is con¬ verted by a cheap and skilful pud¬ dling process, into a very fibrous bar iron, of great strength and ductility. But this iron is puddled and re-heated at the lowest possi¬ ble heat; it is then rolled, and is ready for the market. For hoops, rails, and nails, it is a very useful article, but it is of no use to the blacksmith. Heated to any tem¬ perature above that of the puddling and re-heating furnaces, it returns to its primitive state, in which con¬ dition it becomes worse than the cast iron from which it was origi¬ nally made. None but a very skil¬ ful blacksmith can weld it; for, when slightly re-heated, it falls to coarse sandy pieces, or melts like pig iron. That which thus loses its fibrous texture in heating, the smith calls ‘burnt iron.’ The philosophy of the improve¬ ment of metal consists in the cir¬ cumstance that a part of its impu¬ rities which are originally in che¬ mical combination, are converted into mechanical admixtures. Iron, containing a small amount of car¬ bon, silicon, or phosphorus, is al¬ ways more hard and strong than pure iron. Pure iron is quite soft. Impure iron has the property of crystallizing, or being suddenly cooled: the size of these crystals is proportional to the amount of carbon in chemical combination with the iron, in proportion to other matter. Between the crys¬ tals minute spaces are left, which serve for the absorption of oxygen. By this means, silicon and calcium may be oxidized, but not carbon, phosphorus, and sulphur. The metal improves in quality in pro¬ WRO portion as oxygen finds access to ! its impurities. The absolute cohesion or strength I of wrought iron is not dependent upon the degree of purity of the metal, but upon a given mixture of cinder and iron. Pure iron, which is always soft, may be required for various purposes, as in the manu¬ facture of cast steel; but, in most cases, an impure but fibrous iron is preferable. In making wrought iron, the main difficulty consists, not in producing fibres in the first stages of the operation,—for this may be accomplished by almost every experienced manufacturer, — but in retaining these fibres through every subsequent stage of the operation. Wrought iron of good quality is silvery white and fibrous; carbon imparts to it a bluish, and often a gray colour: sulphur, a dark, dead colour, without a tinge of blue: silicon, phosphorus, and carbon, a bright colour, which is the more beautiful the more the first two elements preponderate. The lustre of iron does not depend principally upon its colour; for pure iron, al¬ though silvery white, reflects but little light. A small quantity of carbon in chemical combination, phosphorus, or silicon, increases its brilliancy. Its lustre is diminished by silex, carbon in mechanical ad¬ mixture, cinder, lime, sulphur, or magnesia. Good iron should ap¬ pear fresh, somewhat reflex in its fibres, and silky. A dead colour indicates a weak iron, even though it is perfectly white. Dark but very lustrous iron is always supe¬ rior to that which has a bright co¬ lour and feeble lustre. Coarse fibres indicate a strong, but, if the iron is dark, an inferior article. Where the iron is of a white, bright co¬ lour they indicate an article of superior quality for sheet iron and boiler-plate, though too soft for railroad iron. For the latter pur¬ pose, a coarse, fibrous, slight lv 582 YELLOW LAKE. ZEB bluish iron is required. Iron of short fibre is too pure; it is gene¬ rally hot-short, and, when cold, not strong. This kind of iron is apt to result from the application of an excess of lime : its weakness is the result of the absence of all impuri¬ ties. The best qualities of bar iron always contain a small amount of impurity. Steel ceases to be hard and strong, when deprived of the small amount of silicon it contains, or if the silicon is oxidized by re¬ peated heating. This is the case with bar iron. If deprived of all foreign admixture, it ceases to be X. YEL a strong, tenacious, and beautiful iron, but becomes a pale, soft me¬ tal, of feeble strength and lustre. Good bar or wrought iron is always fibrous : it loses its fibres neither by heat nor by cold. Time may change its aggregate form ; but its fibrous quality should always be considered the guarantee of its strength. Iron of good quality will bear cold hammering to any ex¬ tent. A bar an inch square, which cannot be hammered down to a quarter of an inch, on a cold anvil, without showing any traces of splitting, is an inferior iron. Xebec, in navigation, a small three- masted vessel, without a bowsprit, principally used in the Mediter¬ ranean. Xenodochium, a room in a monastery for the reception and entertain¬ ment of strangers, pilgrims, and the relief of paupers. XP. I., the initials of the Greek Yacht, in navigation, a small ship for carrying passengers. Yard, a court enclosed by walls and other buildings; also a measure of 3 feet; a yard or yerd was an¬ ciently a spar or rafter in a timber roof. Yardland, a certain quantity of land, called, in Saxon, gyrdlander; in Latin, virgata terrae : in some places it is 20 acres of land, in others 24 or 30. Yellow is the first of the primary or simple colours, nearest in relation to and partaking most of the nature of the neutral white : it is accord¬ ingly a most advancing colour, of great power in reflecting light. Compounded with the primary red, it constitutes the secondary orange and its relatives, scarlet, etc., and other warm colours. Yellow Lake. There are several pig¬ names of Christ; a monogram, re¬ presented in paintings and mosaics by the Greek Christians. \ Xylography , the art of engraving on wood. Xystos, in ancient architecture, a large portico in the gymnasium, for the accommodation of the wrestlers; a sheltered walk. ments of this denomination, vary¬ ing in colour and appearance, ac¬ cording to the colouring substances used and modes of preparation. They are usually in the form of drops, and their colours are, in general, bright yellow, very trans¬ parent, and not liable to change in an impure atmosphere,—qualities which would render them very valuable pigments, were they not soon discoloured and even de¬ stroyed by the opposite influence of oxygen and light, both in water and oil, in which latter vehicle, like other lakes in general, they are bad dryers, and do not stand the action of white lead or other metallic colours. If used, there¬ fore, it should be as simple as possible. Yellow Ochre, called also Mineral Yellow, is a native pigment, found 583 YEL ZIGZAG MOULDING. ZIN in most countries, and abundantly in our own. It varies considerably in constitution and colour, in which latter particular it is found from a bright but not very vivid yellow to a brown yellow, called spruce ochre, and is always of a warm cast. Its natural variety is much increased by artificial dressing and com¬ pounding. Yellow Orpiment, or Yellow Arsenic, is a sulphurate oxide of arsenic, of a beautiful, bright, and pure yellow colour, not extremely durable in water, and less so in oil. In tint with white lead, it is soon de¬ Zebra wood is the produce of the Brazils and Rio Janeiro ; it is sent in logs and planks as large as 24 inches. The colour is orange- brown and dark-brown variously mixed. Its beautiful appearance fits it for cabinet-work and turnery. Zero, the commencement of a scale marked 0, or nothing. It usually denotes the point from which the scale of a thermometer is gradu¬ ated. Zeta, presumed to be a room over the porch of a Christian church. Zigzag, a moulding by lines arranged in the manner of the heraldic chevron. Zigzag is found fre¬ quently used in Norman and An¬ glo-Norman architecture. Very many beautiful specimens of this ornament exist in doors and win¬ dows of the Anglo-Norman Gothic in England. (See Doors, and the Frontispiece for an early speci¬ men.) Zinc. This metal exists in abundance, and is employed for many pur¬ poses. It is commonly combined with sulphur in zinc blende, and with carbonic acid in the mineral calamine, which is the most valu¬ able of all its ores. Zinc may be obtained pure by redistilling in a porcelain retort, which is sold in commerce. It is obtained from the stroyed. It is not subject to dis¬ coloration in impure air. Yew. The yew-tree is common in Spain, Italy, and England, and is indigenous to Nottinghamshire. The tree is not large, and the wood is of a pale yellowish-red colour, handsomely striped, and often dotted like amboyna. It has been long famed for the construction of bows, and is still so employed. The English species is a hard, tough, and durable wood, and lives to a great age. It is also used for the making of chairs, the handles of articles of furniture, etc. ores as follows: they are first washed and mixed with powdered coke or charcoal, are distilled from an earthern close vessel, with an iron tube passing through its bottom, the upper end of which is open, and the lower end entering a vessel of water. At a bright red heat zinc votalizes, and is con¬ densed in the water, gases passing off along with it. It is a bluish- I white metal, which slowly tarnishes j in the air. It is brittle at ordinary temperatures, but at about 300° it is malleable, and may be rolled or hammered into sheets, and retains ! its ductility when cold. At 400° it may be reduced to powder: it melts at 773°. Zinc white is an oxide of zinc which has been more celebrated as a pig¬ ment than used, being perfectly durable in water and oil, but want¬ ing the body and brightness of fine white leads in oil; while, in water, constant or barytic white and pearl white are superior to it in colour, and equal in durability. Never¬ theless, zinc white is valuable as far as its powers extend in painting, on account of its durability both in oil and water, and its innocence with regard to health; and, when duly and skilfully prepared, the co¬ lour and body of this pigment are 584 ELECTRIC TELEGRAPH. sufficient to qualify it for a general use upon the palette, although the pure white of lead must merit a preference in oil. Zocle, to name given to a low, plain, square member or plinth support¬ ing a column. Zoophorus, in architecture, a part between the architraves and cor¬ nice, so called on account or the ornaments carved on it, among which are the figures of animals. Zyghyr-, or Sigger, in mining. When a slow stream of water issues through a cranny, it is said to sigger, or zyghyr. ADDENDA. ELECTRIC TELEGRAPH. Electric Telegraph. The employment of electricity in the transmission of intelligence originated at an early period of the history of electrical science. Plans to this effect had been brought before the public ; but all wanted a simplicity of prin¬ ciple and of construction. In 1837, Messrs. Cooke and Wheat¬ stone obtained their first patent for an electric telegraph, applicable to general purposes. This patent has been subsequently followed at short intervals by others, in which the invention has been gradually brought to its present form ; the principles originally employed have been progressively rendered more varied and general in their ap¬ plication, and the apparatus more simple in its details. By these improvements the number of wires necessary for the conveyance of intelligence has been reduced, and the construction has been rendered cheaper and more perfect. The electric telegraph involves in its construction two essential principles. First, that a magnetized needle, which is free to rotate about its centre, being brought near to a wire, through which an electric current is passing, has a tendency to place itself at right angles to that wire ; the direction of its motion following a certain invariable law. This fact was the discovery of Prof. (Ersted, of Co¬ penhagen, in 1819. Secondly, that a piece of soft iron, not being per¬ manently magnetic, is rendered temporarily so during the trans¬ mission of an electric current along a wire coiled spirally around it. The figures to which reference is here made, in the brief descrip¬ tion of the apparatus, are, 1. A view of the interior of the single¬ needle instrument, showing the position of the coil and of the battery connections. A vertical section of the same, through the coil and handle. 3. The handle or key, in the position for giving a signal, part being removed, to ren¬ der the battery connections more distinct. 4. Plan of the same. The double-needle instrument differs from the single-needle only in the duplication of all the parts. The coil a, figs. 1 and 2, consists of a light hollow frame of brass or wmod, around which are wound, in two portions, about 200 yards of fine copper wire, covered with silk or cotton. This length of wire renders the indications of the nee¬ dle distinct and prompt, even with a low-battery power, or when form¬ ing part of a very extended circuit. The resistance which would be of¬ fered by the fine wire of the coil (its diameter being about i^yth of an inch) to the passage of a current of electricity, derived from an or¬ dinary battery of a few cells only, is overcome by using a battery ar¬ rangement of considerable inten¬ sity, but which developes the elec¬ trical fluid only in small quantity. 585 586 ELECTRIC TELEGRAPH. Or, speaking rather more correctly, we should say, that the electro¬ motive resistance, both of the bat¬ tery and also of the ordinary circuit, being very considerable, the intro¬ duction of the resistance of the coil into the latter produces but little influence upon the transmis¬ sion of the current. Within the brass frame, and therefore interior to the coils of wire, is suspended a magnetic needle, upon a horizontal axis b, which passes across the middle of the frame, and turns on fine pivots at the back and front of the coil. In front of the frame and of the dial of the instrument is fixed on the same axis b, a second needle having its poles oppositely placed to those of the first. This outer needle serves as the indicator or pointer, by which the signals are made, and at the same time is acted upon by the eoil, though in a less degree than the inner needle. The combination of the two needles being thus rendered astatic, it is necessary to give a slight prepon¬ derance to their lower ends, in or¬ der that they may recover their vertical position, after having been deflected ; and the action of gravity has been found more effectual, in bringing the needle to rest without oscillations, than either springs ap¬ plied at the sides, or the directive influence of permanent magnets. With the coil and needles thus ar¬ ranged, it is evident that signals may be given by the combination of successive deflections to one side or the other; the extent of such deflections being limited to any degree that may be found con¬ venient, either by pins fixed on the dial of the instrument, or by stops placed at the sides of the brass frame of the coil. In fact, all that is necessary for rendering these movements of the needle available for the transmission of intelligence, is a contrivance for reversing with ease and rapidity the connection of the battery with the ends of the two conducting wires. This expe¬ dient is provided by the handle or key of the instrument. The conductor through which the electrical current is to circulate must be absolutely complete in all parts. It is not necessary that the material of the circuit be the same throughout, but only that its con- ductibility be maintained from the one pole of the battery to the other; the slightest want of con¬ tinuity of the conducting matter, at any part of the circuit, being fatal to the passage of the fluid. So long as the wires for telegra¬ phic purposes were extended be¬ tween the two points of communi¬ cation, by being laid within tubes buried in the earth, a second wire was requisite to enable the current to return from the distant station to the point whence it set out. It was well known that the earth itself afforded such a means of return; but the insulation of the wires in the tubes from the earth could not be rendered sufficiently perfect to make the use of the earth, as a portion of the circuit, either prudent or desirable. When, however, the wires were suspended in the air, according to Mr. Cooke’s patent of 1842, the earth was ad¬ vantageously employed as half the circuit. All that was found neces¬ sary, was to connect the extreme ends of the conducting wire with plates of copper or other metal of two or three feet of surface, buried at some depth in the ground ; or with any system of gas or water- pipes, which might afford a con¬ tinuous metallic path for the fluid to the earth. In either case, the depth of the connection beneath the surface must be sufficient to ensure certain contact with moist earth or with water, provided that this latter be not confined within any cistern or reservoir. When all these precautions have been taken, the passage of electri¬ city is readily effected, the earth 587 No. ELECTRIC TELEGRAPH. 588 ELECTRIC TELEGRAPH. appearing to offer little or no re¬ sistance to its progress. Accord¬ ing to the law established by Ohm, the resistance of any conductor varies directly as its length, and in¬ versely at its sectional area. The earth may evidently be regarded as a conductor, of which the dia¬ meter is infinite, compared with its length, and we might therefore be led to expect the result mentioned above. To return, however, to the de¬ scription of the apparatus, the key or handle by means of which the connection of the battery is effected and varied, consists of a cylinder, in which is a middle zone, e, of hard wood or ivory, while the ends are of metal. One of these ends, c, extending through the case in front, forms the actual handle; while the other, d, is turned down to a shoulder and forms a pivot, which rests in a brass collar, p. The eni d carries a steel pin, f projecting upward, and c, a similar pin g, directed downward. The battery being connected with the terminals z and c, and thence by the brass strips k and m, of which the extremities rest as springs on the metallic ends of the cylinder, may in fact be considered as having its poles at the two pins, ./and g, which are fixed in those ends. Two springs, h and h\ are fixed by broad feet to the base of the in¬ strument, and rest by their upper extremities on two studs or points projecting from a brass rod, i, screwed into the case in front. These springs form the circuit be¬ tween the terminal 1 1, with which one end of the conducting wire is connected, and l 4. Between this latter terminal and the external connection, l 2, the coil itself, and the brass strip extending from l 3 to l 2, are interposed. When a signal is being sent through the instrument (supposed to hold the place of No. 2 in fig. 5), the cur¬ rent from No. 1 being considered to enter from the long wire on the line, by the terminal l 2, passes along the brass strip to the terminal l 3, thence through the coil to l 4; then to the spring h, across the pin i, down the spring h', and to the terminal 1 1 in connection with the wire leaving the station. Were the instrument in question situated as No. I or No. 3, it will be seen that one of the terminals, 1 1 or / 2, according to its position, would be joined to the wire coming from the earth-plate. When a signal is to be given by the instrument, the handle being turned as in figs. 3 and 4, one battery-pin, f, is brought in con¬ tact with the spring h', which is bent back and released from its contact with i, while the other battery-pin g, is pressed against the foot of the other spring h, which at this part is turned up to act as a stop. The current being then sup¬ posed to start from the pole/, pro¬ ceeds down the spring h', to the coil and terminal l 2, as before; thence along the line through the other instruments, and into the earth at the further extremity of the line. Re-ascending from the earth by the wire connected with the terminal l I, it gains the foot of the spring h, with which the second battery pole g, is in con¬ tact. It will be seen that the direction of the current is different, according as the key is turned to the right or left. The position of the battery wires is such, that the needle shall be deflected in paral¬ lelism to the handle. A comparison of fig. 5, in which three instruments are shown in series, with the figures I, 2, 3, and 4, will render the method of connection, both of the two terminal and of the inter¬ mediate instruments, sufficiently obvious. The wires on entering a station are designated as ‘ up’ or * down’ wires, according to the portion of the line from which they come. Care must be, of course, 589 ELECTRIC TELEGRAPH. 590 ELECTRIC TELEGRAPH. taken that all the instruments in one series are similarly joined to the up and down wires, so that the course of the current may be alike in all. At the extreme ‘ up sta¬ tion’ the earth connection becomes the ‘ up wire,’ and at the opposite terminus it takes the place of the 4 down wire,’ The electric fluid is represented as starting from one pole of the bat¬ tery only, and, after traversing the circuit, returning to the other pole. It is, however, more consonant with the theories deduced from the observation of electrical pheno¬ mena, to suppose that force is developed equally at both poles of the battery. The second principle is that of the temporary magnetization of soft iron by the electric current, applied for the purpose of sounding an alarum at a distant station, in order to summon the attendant to his instrument. The same princi¬ ple has been employed from an early period of the invention, both by Mr. Cooke and by Prof. Wheat¬ stone, to transmit visible signals by causing the rotation of a disc, bearing letters or figures, or of a hand or index pointing to charac¬ ters on a fixed dial; but in Eng¬ land the needle telegraph has been universally adopted, in preference to any other form. Many improve¬ ments have, however, been effected within the last few years by Prof. Wheatstone in the construction of the mechanical telegraph, as it has been named in contradistinction to the needle instrument. The same gentleman has also succeeded in substituting for the voltaic battery in the working of this telegraph, the magneto-electric machine, in which the current is derived by induction from a permanent mag¬ net. The improvement which was effected by this adoption of a source of power, alike energetic and un- a'terable, will be immediately per¬ ceived. Telegraphs on this plan of construction have been erected in Prussia and France, and, were it not for some very marked advan¬ tages connected with the use of the needle signals, they could hardly fail to become general.' The ringing of the alarum was originally effected by the direct action of the voltaic magnet upon the hammer of the bell; but this method has been long superseded. The apparatus generally in use for this purpose is shown in a front and back view in figs. 11 and 13, and in a side view at figure 12. An electro-magnet is formed by coiling fine insulated copper wire around two cylinders of very soft pure iron. These coils, c c, are then connected by two of their ends, in such a manner that the direction in which the wire is wound about the iron cores may be alike in both. The iron cylin¬ ders are joined together at one end by a cross-piece d, likewise of soft iron, so that the whole then forms a horse-shoe magnet, having how¬ ever its two sides parallel. In front of the free ends or poles of this magnet, which is fixed on the top of the plates of the alarum, an arm - ature a, of soft iron, is placed at such a distance that it may be strongly attracted by the electro¬ magnet when the circuit is com¬ pleted through its coils. The arm¬ ature moves on an arbor, upon which a detent or catch e, is fast¬ ened, and so arranged that it is disengaged from a small fly v, when¬ ever the attraction takes place. This disengagement allows a train of clock-work, impelled by a spring or weight, to run down, and by the action of a scape-wheel and pal¬ lets, seen in fig. 11, a hammer, h, rapidly strikes a small bell g. Im¬ mediately, however, that the cur¬ rent ceases to flow through the coils, the iron within them loses its magnetism, a small re-acting spring, s, draws back the armature, and interposes the detent so as to 591 ELECTRIC TELEGRAPH. 592 ELECTRIC TELEGRAPH. stop the clockwork. It is neces¬ sary that the iron of the magnet should be quite pure and soft, as otherwise the magnetization is to a greater or less degree permanent; and this may be the case to such an extent as to keep the armature attracted, even after the cessation of the electric current. The bell would then continue to ring until the disengagement of the armature were caused by the hand of the attendant. The bell or alarum may form part of the telegraphic system in two modes. In the first, and most economical, its coil is made to form part of the circuit of one of the needle wires, in conjunction with a key or rheotome. In the second and more complete method of in¬ troducing the alarum, a distinct wire is employed for it, in the course of which the magnet coils at the several stations are inter¬ posed. A key of different con¬ struction (shown in section at fig. 14) is then employed. The body is of brass, but two stout wires, z and c, are conducted through ivory tubes, and terminated in studs, pp, at the top and bottom of the cylin¬ drical end of the key; the wires and studs being insulated from each other, and from the key, by the ivory in which they are fixed. The collar f, and nut, t, serve to se¬ cure the key to the side of the case or box in which it is placed, the former, t\ also containing the spring, by which, after use, the key is brought back to its quiescent position. Two springs, not shown in the figure, then rest against the metal of the end, one on each side, and while in this position, merely complete, by the intervening metal, the circuit of the bell-wire which is connected to the foot of one spring directly, and to the foot of the other by the intervention of the bell coil. The wires, z and c, are joined to the two poles of the battery by pieces of thin wire, which will offer no resistance to the revo¬ lution of the key on its axis. In the quiescent position, the course of a current entering from a distant station would be, from the line- wire on one side, along one spring, across the body of the key to the other spring, and thence through the alarum coil to the continuation of the line-wire, or to the earth connection. When, however, the bell is to be rung to call the atten¬ tion of the clerk at another station, the key is for a moment turned one- quarter round. This brings the battery studs, p p, into the circuit, instead of the body of the key; and the current then proceeds from the battery of the ringing station by the spring and wire on one side, 1 passes along the line, and returns I by the earth through the other spring again to the battery. The relative advantages of these two methods may be briefly stated, The first has the recommendation of economy, inasmuch as no addi¬ tional wire is ^necessary for the bell. If, however, the clerk in charge of an instrument, after turning off his bell preparatory to sending or transmitting intelli¬ gence, should chance to leave his telegraph, and omit' to turn the key so as to replace the bell in the circuit, no means are left to other stations of calling his attention, except by working the needles, with the chance of their movement meeting his eye. By the adoption of the second method, the expense of an additional wire is incurred, but the bells at all stations are constantly in a position to be rung if necessary. In addition to this, it may be remarked, that by keep¬ ing the bell and needles distinct from each other, no derangement of the one is to be feared from injury to or derangement in the other. Mr. Cooke’s first plan, in the extension of the conducting wires between distant points, was, as has 593 ELECTRIC TELEGRAPH. been already stated, to cover each wire with cotton or silk, and then with pitch, caoutchouc, resin, or other non-conducting material, and to enclose them, thus protected, in tubes or pipes of wood, iron, or earthenware. Excepting in those localities where the suspension of wires is impracticable, as in streets, towns, or on public roads, the early plan has given place to more re¬ cent inventions. In 1842, a patent was obtained by Mr. Cooke, for a means of suspending and insulating the wires in the air, and the me¬ thod described in his specification has been since adhered to, with little variation. The wires are generally of iron, which is galva¬ nized, to protect it from the action of the atmosphere. They are of about one-sixth of an inch in dia¬ meter, corresponding to No. 8 of the wire-gauge. Being obtained in as great lengths as possible in the first place, successive pieces are welded together, until a coil of about 440 yards is formed. These rings or bundles weigh about 120 pounds each. The wires are sus¬ pended on the line, from stout squared posts or standards, of Dantzic or Memel timber. At each quarter-mile, a stronger post is fixed, from which the succeeding lengths of wire on either side are strained or tightened up. Inter¬ mediate to these principal posts, are placed smaller standards at from 45 to 55 yards asunder, for the purpose of supporting the wires. The straining apparatus is very simple, consisting merely of a reel or pulley, turning between two cheeks of cast iron, and carrying upon its axis a ratchet-wheel, into the teeth of which a click or catch falls. These winding heads, shown at r r, figs. 7 and 9, are connected through the post by a bolt of wrought iron, b, tapped into each head. This bolt not only bears the strain of the wires, but also forms the metallic communication between their ends wound on the two reels. In order to insulate the bolt from the wood of the post the hole in this latter is bored very large, and collars of earthenware, t t, are inserted at each side, in which the bolt rests, and against their outer surfaces the winding heads are screwed up tight. Fig. 9 is a section through the post and collar, showing this arrangement. Fig. 7 is a front, and 8 a side view of the head of a straining or quarter- post. The wires are usually arranged in two vertical planes, at the back and front of the standards, or intermediate posts. They are not strained at each quarter-mile, but at intervals of half a mile al¬ ternately ; those in the front plane at one post, and those in the back plane at the next. The standards or supporting posts have merely to sustain the weight of the wires without relation to their tension. They have on each side two stout arms of oak or ash, secured by bolts, passing from one to the other, and resting in collars of earthenware, x x, where they pass through the standard. The wires pass through pieces of earthen¬ ware, of a double cone shape, e e, fastened to the outside of the arms by staples or clips, having a nut and screw at the end. These staples embrace the cones at a groove in the middle of their length. An arm similar to those on the stand¬ ards is fixed to the back and front of each post alternately, to support that plane of wires which passes without being strained. The in¬ sulating earthenwares between the arm and post, y y, are, however, different in shape from those used with the standard arms, as greater length is requisite. In passing through tunnels and bridges, or in front of walls or buildings, where posts cannot be conveniently fixed in the ground, the wires are supported on octago¬ nal standards of oak or ash, fixed 594 ELECTRIC TELEGRAPH. at about six inches from the wall by holdfasts of galvanized iron. The batteries employed are in the form of a Wollaston’s trough, in which are arranged plates of copper and amalgamated zinc, each cell being filled with dry and clean sand. When about to he used, the sand is just moistened with dilute sulphuric acid. These batteries are singularly constant, having been known to remain in action during a period of from two to five months, with only the occa¬ sional addition of a little more acid solution, to supply the waste by evaporation and saturation. The effect of the sand appears to he, the prevention of too rapid an ac¬ tion, and, at the same time, the separation of the sulphates of cop¬ per and zinc. No copper is there¬ fore deposited on the zinc plate. The points necessary to be observed are the perfect amalgamation of the zinc, the absolute freedom of the sand from lime or other alkali, from carbonates or muriates, and the purity of the sulphuric acid. The zinc is about £ or of an inch thick, and is in pieces of inches by 3 inches. These plates will last with care for five or six months in almost constant action. A battery series of from 12 to 60 pairs is required, according to the length and nature of the line and the number of instru¬ ments in connection. ^ Six wires are extended along the whole length of railway, of which the upper pair are used with a spe- The following are the principal dimensions of the posts and poles : cial double-needle instrument, for verbal communication, between the main stations, which are Nor¬ wich, Brundall, Reedham, and Yar¬ mouth. Each of the other four wires includes at every station a coil and single needle. On the dials connected w'ith the first wire of these four, is engraved the name Norwich at all the stations; with the second, that of Brundall, with the third Reedham, and with the fourth Yarmouth. The distinct telegraphic system belonging to each station has, therefore, its re¬ presentative at all the other sta¬ tions. Each needle or pointer re¬ presents the state of the portion of line under the control of the sta¬ tion the name of which it bears. The alarum of each instrument is connected only with the wire of its own station, so that on moving either of the needles, the alarum will be rung at the place corre¬ sponding to the name of the needle, but at no other point, although the movement of the pointer will be visible throughout. The electric telegraph is now the chief mode oftransmi tting all the news of the Government, and the important correspondence of merchants and of the public gene¬ rally. Its influence is now all-im¬ portant; its extension to the several civilized and commercial countries, across the seas, by means of the sub¬ marine cable, is one of the great aims of science in the present day. LENGTH. AT BASE. AT TOP. Posts. Standards. Posts. Standards. ft. in. in. in. in. in. in. in. in. 18 9x8 6 x 6 7 x 6i H x 4i 22 10 x 8 7x6 do. do. 28 11 x 10 8x7 do. do. 595 RENAISSANCE. Renaissance. —This term is applied to a style which arose in all the arts of design, from the introduc¬ tion of antique features, consequent on the revival of classical learning, and the admiration of everything • classical after the fall of the Gothic system. In Italy, where the arts had never become thoroughly Gothic, the renaissance of classical taste commenced as early as the 13th cen¬ tury, but in the rest of Europe the Gothic had then hardly arrived at its complete development, or had hardly begun to display its lux¬ uriance'; and two centuries were required to explore its capabilities, to work out its resources in all their wondrous variety, and to push on its suggestions so far in complication . ‘ and absurdity, as to render a change of style necessary; and accordingly the arts of Germany, the Nether¬ lands, France, and England, were not ripe for this change, called the ‘ renaissance, 5 till the end of the 15th or beginning of the 16th cen¬ tury-; i. e. not till after the inven¬ tion of printing, the great change of society resulting from which rendered easy the introduction of classic taste into these countries. In architecture, renaissance of classical forms and principles first distinctly shows itself in the works of Brunelleschi, the great Floren¬ tine architect, who lived from 1375 to 1444, His most famous work, the cupola of the cathedral, exhibits a bold emancipation from Gothic complexity, and return to classic simplicity. Contemporary were Michelozzo, and L. B. Alberti, the first modern writer on the art. They were succeeded by Cronaca and Bramante, the latter of whom re-introduced detached colonnades and hanging architraves. His successor, Michael Angelo, with his genius for seizing whatever was j grand rather than beautiful, re¬ turned (in the Capitoline Museum) to the classic simplicity of a single order, and an entablature unbroken from corner to corner: the re¬ naissance was thus complete. San- micheli of Verona (1484-1549) originated the fanciful and luxuri¬ ous school which characterized the renaissant architecture of Venice, and became the favourite model for the schools of all transalpine coun¬ tries, especially England. In this country, the way was prepared by certain tendencies of our After-Gothic, the florid Per¬ pendicular, and Tudor; as (I.) the tendency to subordinate the arch and archlet to the framework of vertical and horizontal lines. (II.) By these horizontal masses of moulding beginning almost to approximate the effect of classic entablatures, in their division into two groups, like cornice and archi¬ trave. (HI.) By the roofs being reduced in pitch, and by towers being finished without spires. (IV.) By the depression of the arch, and the diminishing importance attached to its point. (V.) By the introduction of a large and bold scale of carved ornament, and by the introduction of attached orna¬ ment, contrary to the Gothic prin¬ ciple of decorating by the removal of superfluous material, and not, as in classic architecture, by addition. These several predisposing ten¬ dencies of our debased After-Gothie rendered it easy to engraft there¬ on those Italian details which dis¬ tinguish the works of the reign of Henry VIII. The chantries of Bishops Fox and Gardiner, at Winchester, are instructive ex¬ amples of this process ; and so are the tomb of Henry VII., the wood¬ work of King’s College chapel, and much of the architecture of Cam¬ bridge. FEINTED BY 3 . E. TAYLOE, LITTLE QUEEN STREET* LINCOLN^ INN FIELDS. 596 w / - a ' \ \ J ' il- & \t*b _