.-J'W'li'- C-W- ^ W^. - T:^: -T- ^ ■•* • ' v '-.' ‘*^ '''^ ’‘•'-»t>r» ii ♦-bL, *_. ■ T‘* *..3^- Tjc >/ 1 # f ’< *; # # -• •V ■?? ^ ’ f '■ ■* /i* *-' ■’ - ^ "i ‘St ^ ' - •P'’ _ ■•! ^ ^ jp *. w ^ > f- ■ f,ki; ■ •' * Jirw _■ * ’^'V^ < a, \ "'V; ., ^ , • it * # * J ■ S } ■*^.' “* . Jii rv; - 4 ^ ^ v;’'*r ,. * y-' • ' •' (-'■^‘ .tL •* r%. ^ i^':— - £'<>» ;:. 4 v' A A 4:*' • 0 • : ^ V i,. - ^ .f • ^ • ^ 1 -. ■ r / -Ji* .: ■ •; * jr-W . tr 3 f -; - ' '-i Jifk ' “IS* >■ ' . f . 11 - S T I\]ST m E PimTnT'if Qnr ] THE USEFUL ARTS, CONSIDERED IN CONNEXION WITH THB APPLICATIONS OF SCIENCE: WITH NUMEROUS ENGRAVINGS. BY JACOB BIGELOW, M.D. PRorsssoB or materia medica in harvard university, author or ‘ THE ELEMENTS OF TECHNOLOGY,’ ETC. ETC. IN TWO VOLUMES. VOL. II. HARPER & BROTHERS, PUBLISHERS, 82 CLIFF STREET, NEW YORK. 1851 . Entered according to Act of Congress, in the year 1840, by Marsh, Capen, Lyon, and Webb. in the Clerk’s Office of the District Court of Massachusetts THE GETTY RESEARCH INSTITUTE LIBRARY CONTENTS. CHAPTER XIV. ARTS OF LOCOMOTION. Motion of Animals ; Inertia ; Aids to Locomotion. Wheel Carriages :—Wheels ; Rollers ; Size of Wheels ; Line of Traction ; Broad Wheels ; Form of Wheels ; Axletrees ; Springs ; Attaching of Horses. Highways:—Roads; Pavements; Wood¬ en Pavements; McAdam Roads. Bridges: — Wooden Bridges ; Stone Bridges ; Cast-Iron Bridges ; Suspension Bridges ; Floating Bridges. Rail Roads :—Edge Rail-way ; Tram Road ; Single Rail ; Passings, or Sidings ; Turn Plate ; Curves ; Propelling Power ; Locomotive Engines ; Station¬ ary Engines. Canals :—Embankments ; Aque¬ ducts ; Tunnels ; Gates and Weirs ; Locks; Boats ; Size of Canals. Sailing :—Form of a Ship; Keel and Rudder ; Effect of the Wind ; Stability of a Ship ; Steam Boats ; Steam Ships. Diving Bell:—Submarine Navigation. Aerostation :—Bal- oon; Parachute,..9 4 CONTENTS. CHAPTER XV. ELEMENTS OF MACHINERY. Machines ; Motion. Rotary, or Circular Motion Band Wheels ; Rag Wheels ; Toothed Wheels ; Spiral Gear ; Bevel Gear ; Crown Wheels ; Uni¬ versal Joint ; Perpetual Screw ; Brush Wheels ; Ratchet Wheel ; Distant Rotary Motion ; Change of Velocity ; Fusee. Alternate, or Reciprocating Motion :—Cams ; Crank ; Parallel Motion ^ Sun and Planet Wheel ; Inclined Wheel ; Epicycloidal Wheel ; Rack and Segment ; Rack and Pinion ; Belt and Segment ; Scapements, Continued Rec¬ tilinear Motion :—Band ; Rack ; Universal Lever ; Screw ; Change of Direction ; Toggle Joint. Of Engaging and Disengaging Machinery. Of Equal¬ izing Motion :—Governor ; Fly Wheel. Friction. Remarks, . ... CHAPTER XVI. OF THE MOVING FORCES USED IN THE ARTS. Sources of Power ; Vehicles of Power. Animal Pow¬ er ;—Men; Horses. Water Power :—Overshot Wheel; Chain Wheel ; Undershot Wheel ; Back Water ; Besant’s Wheel ; Lambert’s Wheel ; Breast Wheel ; Horizontal Wheel ; Barker’s Mill. Wind Power :—Vertical Windmill; Adjustment of Sails ; Horizontal Windmill. Steam Power :— Steam ; Applications of Steam ; By Condensation ; By Generation ; By Expansion ; The Steam En¬ gine ; Boiler ; Appendages ; Engine ; Noncon¬ densing Engine ; Condensing Engines ; Descrip¬ tion ; Expansion Engines ; Condenser; Valves ; Pistons ; Parallel Motion ; Locomotive Engine ; CONTENTS. 5 Power of the Steam Engine ; Projected Improve¬ ments ; Rotative Engines ; Use of Steam at High Temperatures ; Use of Vapors of Low Tempera¬ ture ; Gas Engines; Steam Carriages ; Steam Gun. Gunpowder ;—Manufacture ; Detonation ; Force ; Properties of a Gun ; Blasting. Magnet¬ ic Engines,.81 CHAPTER XVIL ARTS OF CONVEYING WATER, Of Conducting Water ;—Aqueducts ; Water Pipes ; Friction of Pipes ; Obstruction of Pipes ; Syphon. Of Raising Water: — Scoop Wheel; Persian Wheel ; Noria; Rope Pump ; Hydreole ; Archi¬ medes’ Screw ; Spiral Pump ; Centrifugal Pump ; Common Pumps ; Forcing Pump ; Plunger Pump ; De La Hire’s Pump ; Hydrostatic Press ; Lifting Pump ; Bag Pump ; Double-acting Pump ; Rol¬ ling Pump ; Eccentric Pump ; Arrangement of Pipes ; Chain Pump ; Schemnitz Vessels, or Hun¬ garian Machine ; Hero’s Fountain ; Atmospheric Machines; Hydraulic Ram. Of Projecting Water : —Fountains ; Fire Engines ; Throwing Wheel, . 135 CHAPTER XVTII. ARTS OF COMBINING FLEXIBLE FIBRES. Tlieory of Twisting ; Rope Making ; Hemp Spin¬ ning. Cotton Manufacture :—Elementary Inven¬ tions ; Batting ; Carding ; Drawing ; Roving ; Spinning ; Mule Spinning ; Warping ; Dressing ; Weaving ; Twilling ; Double Weaving ; Cross Weaving ; Lace ; Carpeting ; Tapestry ; Velvets Linens. Woollens. Felting. Paper Making. Bookbinding,.164 1 * 6 CONTENTS. CHAPTER XIX. ARTS OF HOROLOGY. Sun Dial ; Clepsydra ; Water Clock ; Clock Work ; Maintaining Power ; Regulating Movement ; Pen¬ dulum ; Balance ; Scapement ; Description of a Clock ; Striking Part ; Description of a Watch, 187 CHAPTER XX. ARTS OF METALLURGY. Extraction of Metals ; Assaying ; Alloys. Gold :— Extraction ; Cupellation ; Parting ; Cementation ; Alloy ; Working ; Gold Beating ; Gilding on Met¬ als ; Gold Wire. Silver :—Extraction ; Working * Coining ; Plating. Copper :—Extraction ; Work¬ ing. Brass : —Manufacture ; Buttons ; Pins ; Bronze. Lead :—Extraction ; Manufacture ; Sheet Lead ; Lead Pipes ; Leaden Shot. Tin :—Block Tin ; Tin Plates ; Silvering of Mirrors. Iron :— Smelting ; Crude Iron ; Casting ; Malleable Iron ; Forging ; Rolling and Slitting ; Wire Drawing ; Nail Making ; Gun Making. Steel :—Alloys of Steel ; Case Hardening ; Tempering ; Cutlery, 208 CHAPTER XXL ARTS OF VITRIFICATION. Glass ; Materials ; Crown Glass ; Fritting ; Melt¬ ing ; Blowing ; Annealing ; Broad Glass ; Flint Glass ; Bottle Glass; Cylinder Glass ; Plate Glass ; Moulding ; Pressing ; Cutting ; Stained Glass ; Enamelling ; Artificial Gems ; Devitrifica- CONTENTS. 7 tion ; Reaumur’s Porcelain ; Crystallo-CeramLe ; Glass Thread ; Remarks,.247 CHAPTER XXII. ARTS OF INDURATION BY HEAT. Bricks ; Pressed Bricks ; Tiles ; Terra Cotta ; Cru¬ cibles ; Pottery ; Operations ; Stone Ware; White Ware ; Throwing ; Pressing ; Casting ; Burning ; Printing ; Glazing ; China Ware ; Eu¬ ropean Porcelain ; Etruscan Vases,.262 APPENDIX. Artesian Wells. Mines. Depth of Mines. Canals in the United States. Rail-Ways in the United States. Manufacture of Maple Sugar. Manufac¬ ture of Beet Sugar. Voltaic Electrical Engraving. Photogenic Drawing, ..275 Glossary, . . 369 Index, .375 THE USEFUL ARTS. CHAPTER XIV. ARTS OF LOCOMOTION. Motion of Animals, Inertia, Aids to Locomotion, Wheel Carnages, Wheels, Rollers, Size of Wheels, Line of Traction, Broad Wheels, Form of Wheels, Axletrees, Springs, Attaching of Horses. High¬ ways, Roads, Pavements, Wooden Pavements, McAdam Roads. Bridges, 1, Wooden Bridges, 2, Stone Bridges, 3, Cast-Iron Bridges, 4, Suspension Bridges, 5, Floating Bridges. Rail Roads, Edge Rail-way, Tram Road, Single Rail, Passings, or Sidings, Turn Plate, Curves, Propelling Power, Locomotive Engines, Stationary Engines. Canals, Embankments, Aqueducts, Tunnels, Gates and Weirs, Locks, Boats, Size of Canals. Sailing, Form of a Ship, Keel and Rudder, Effect of the Wind, Stability of a Ship, Steam Boats, Steam Ships. Diving Bell, Submarine Navigation. Aeros¬ tation, Balloon, Parachute. ^ C/ Animals, of the more perfect kinds, possess the power of shifting their place, at will, which power they exercise, both in transporting their own bodies, and in conveying other masses of matter. The chief obstacles, which op¬ pose locomotion or change of place, are, gravity and fric¬ tion, the last of which is, in most cases, a consequence of the first. Gravity confines all terrestrial bodies against the surface of the earth, with a force proportionate to the quantity of matter which composes them. Before they can be removed from one spot of this surface, to another, of equal height, they must either be lifted from the ground, against the force of gravity, or carried, horizontally, along the surface, resisting with a degree of friction, which in¬ creases with their weight. Most kinds of mechanism, both natural and artificial, which assist locomotion, are arrangements for obviating the effects of gravity and fric¬ tion. 10 ARTS OF LOCOMOTION. Motion of Animals. —Animals, that walk, obviate fric¬ tion, by substituting points of their bodies, instead of large surfaces ; and upon these points they turn, as upon cen¬ tres, for the length of each step, raising themselves wholly, or partly, from the ground, in successive arcs, instead of drawing themselves along the surface. The line of arcs, which the centre of gravity describes, is converted into an easy, or undulating line, by the compound action of the different joints. As the feet move in separate lines, the body has, also, a lateral, vibratory motion. A man, in walking, puts down one foot, before the other is raised, but not in running. Quadrupeds, in walking, have three feet upon the ground, for most of the time ; in trotting, only two. Animals, which w’alk against gravity, as the common fly, the tree toad, &c., support themselves by suction, using cavities on the under side of their feet, which they enlarge, at pleasure, till the pressure of the at¬ mosphere causes them to adhere. In other respects, their locomotion is effected like that of other walking animals. Birds perform the motion of flying, by striking the air, with the broad surface of their wings, in a downward, and backward, direction, thus propelling the body upward, and forward. After each stroke, the wings are contracted, or slightly turned, to lessen their resistance to the atmos¬ phere, then raised, and spread anew. The downward stroke, also, being more sudden than the upward, is more resisted by the atmosphere. The tail of birds serves as a rudder, to direct the course upward, or downward. When a bird sails in the air, without moving the wings, it is done, in some cases, by the velocity previously acquired, and an oblique direction of the wings, upward ; in others, by a gradual descent, with the wings slightly turned in an oblique direction, downward. Fishes, in swimming foi*- ward, are propelled chiefly by strokes of the tail, the ex¬ tremity of which, being bent into an oblique position, pro¬ pels the body forward, and laterally, at the same time. The lateral motion is corrected by the next stroke, in the op¬ posite direction, while the forward course continues. The fins serve, partly, to assist in swimming, but, chiefly, to balance the body, or keep it upright; for the centre of INERTIA. 11 gravity being nearest the back, a fish turns over, when it is dead, or disabled.* Some other aquatic animals, as leeches, swim with a sinuous, or undulating, motion of the body, in which several parts, at once, are made to act obliquely, against the w^ater. Serpents, in like manner, advance, by means of the winding, or serpentine, direction w'hich they give to their bodies, and by which a succes¬ sion of oblique forces is brought to act against the ground. Sir Everard Home is of opinion, that serpents use their ribs, in the manner of legs, and propel the body forwards, by bringing the plates, on the under surface of the body, to act, successively, like feet, against the ground.f Some worms and larvae, of slow motion, extend a part of their body forwards, and draw up the rest to overtake it; some performing this motion, in a direct line, others, in curves. When land animals swim in water, they are supported, because their whole w^eight, with the lungs expanded with air, is less than that of an equal bulk of water. The head, however, or a part of it, must be kept above water, to enable the animal to breathe ; and to effect this, and also to make progress in the water, the limbs are exerted, in successive impulses, against the fluid. Quadrupeds and birds swim with less effort than man, because the weight of the head, which is carried above water, is, in them, a smaller proportional part of the whole, than it is in man. Inertia .—In consequence of the action of gravity upon bodies, their inertia becomes a greater obstacle to loco¬ motion than it would otherwise be. Every body tends, by its inertia, to preserve a state of rest, if it is still, and of uniform rectilinear motion, if it is not still. Changes, therefore, not only from rest to motion, but also changes * The swimming bladder, which exists in most fishes, though not in all, is supposed to have an agency in adapting the specific gravity of the fish to the particular depth, in which it resides. The power of the animal to rise or sink, by altering the dimensions of this organ, has been, with some reason, disputed. t i.eetures on Comparative Anatomy, vol. i. p. 116, &c. Sir E Home deduces this fact from the .anatomy of the animal, and from the movements which he perceived, in sufi'ering a Large coluber to crawl over his hand. The ribs appeared to be raised, spread, carried for¬ ward, depressed, and pushed backward, successively. 12 ARTS OF LOCOMOTION. of direction, and changes of speed, are resisted by the force of inertia. Bodies moving upon the earth’s surface are obliged, by their gravity, to accommodate their mo¬ tions to the irregularities of this surface, and, consequent¬ ly, to change, often, both their direction and velocity The inertia thus becomes a continual source of expenditure of power, although it would not be so, if bodies moved at a uniform rate, and in a straight course. Aids to Locomotion .—All animals are provided, by Nature, with organs of locomotion best adapted to their structure and situation ; and it is probable that no animal, man not being excepted, can exert his strength more ad¬ vantageously, by any other than the natural mode, in moving himself over the common surface of the ground.* Thus walking-cars, velocipedes, &c., although they may enable a man to increase his velocity in favorable situations, for a short time, yet they actually require an increased expen¬ diture of power, for the purpose of transporting the ma¬ chine made use of, in addition to the weight of the body. When, however, a great additional load is to be transport¬ ed with the body, a man, or animal, may derive much assistance from mechanical arrangements. Wheel Carriages .—For moving weights over the com¬ mon ground, with its ordinary asperities and inequalities of substance and structure, no piece of inert mechanism is so favorably adapted, as the wheel-carriage. It was in¬ troduced into use, in very early ages, as affording a facil¬ ity for the carrying of heavy loads, and, finally, for trans¬ porting man himself; not by his own powers, but by the strength of other animals, which he had subjugated to his use. Chariots were used in war, and w^agons in agricul¬ ture, at a very remote period. Wheels .—The mechanical action of wheels, applied to locomotive carriages, is twofold. They diminish friction, and, also, surmount obstacles, or inequalities, of the road, with more advantage than bodies of any other form, in their place, could do. The friction is diminished, by transferring it from the surface of the ground to the cen- * This remark, of course, does not apply to situations in which fric¬ tion is obviated, as upon water, icc, rail-roads, &c. ROLLERS.-SIZE OE WHEELS. 13 tre of the wheel, or rather to the place of contact, between the axletree and the box of the wheel. So that it is les¬ sened, by the mechanical advantage of the lever, in the proportion, which the diameter of the axletree bears to the diameter of the wheel. The rubbing surfaces, also, being kept pohshed, and smeared with some unctuous substance, are in the best possible condition to resist friction. ^ In like manner, the common obstacles, that present themselves in the public roads, are surmounted by a wheel, with peculiar facilit^^ As soon as the wheel strikes against a stone, or similar hard body, it is converted into a lever, for lifting the load over the resisting object. If an obstacle, eight or ten inches in height, were presented to the body of a carriage, unprovided with wheels, it would stop its progress, or subject it to such violence as would endanger its safety. But, by the action of a wheel, the load is lifted, and its centre of gravity passes over, in the direction of an easy arc, the obstacle furnishing the fulcrum, on which the lever acts. Rollers. —Rollers, placed under a heavy body, diminish the friction in a greater degree than wheels, provided they are true spheres, or cylinders, without any axis, on which they are constrained to move. If the rollers be perfectly elastic, and, also, the plane upon which they move, there will be no sliding friction, whatever ; whereas the wheel always rubs at its axis. But an oflset for this advantage is found in the circumstance, tliat the wheel maintains its relative place, in regard to the load, while the roller constantly falls behind, and is obliged to be taken up and replaced, at an expense of power. A cylindrical roller, likewise, occasions friction, whenever its path de¬ viates, in the least, from a straight line. Size of Wheels .—The mechanical advantages of a wheel are proportionate to its size ; and the larger it is, the more effectually does it diminish the ordinary resist¬ ances. A large wheel will surmount stones, and similar obstacles, better than a small one ; since the arm of the lever, on which the force acts, is longer, and the curve, described by the centre of the load, is the arc of a lar- II. 2 XII. 14 ARTS OF LOCOMOTION. ger circle, and, of course, the ascent is more gradual and easy.* A further advantage is derived from the circumstance, that, in passing over holes, ruts, or excavations, a large wheel sinks less than a small one, and, consequently, occa¬ sions less jolting, and expenditure of power. The wear, also, of small wheels, exceeds that of larger ones; for, if we suppose a wheel to be three feet in diameter, it will turn round twice, while a wheel, six feet in diameter, turns round once. Of course, its tire will come twice as often in contact with the ground, and itg spokes will twice as often have to support the weight of the load. So, that, by calculation, it should last but half the length of time. On these accounts, it would be advantageous to aug¬ ment the diameter of wheels to a great extent, were it not for certain practical limits, which it is not found useful to exceed. One of these is found in the nature of the ma¬ terials, which we are obliged to use, and which, if em¬ ployed to make wheels of great size, at the same time preserving the requisite strength, would render them cum¬ bersome, and too heavy for use.f Another reason, for regulating the size of wheels by a limited standard, arises from the relative size of the animals, commonly employed for draught. A wheel should seldom be of such dimen¬ sions, that its centre would exceed, in height, the breast of the horse, or other animal, by which it is drawn ; because, if this were the case, the horse w'ould draw obliquely downward, as well as forward, and expend a part of his strength in acting against the ground. Line of Traction .—In practice, it is even found neces¬ sary, to place the point of draught, or centre of the wheels, lower than the middle of the horse’s breast, for various reasons. 1. The shape of the animal’s shoulders requires this direction. 2. The horse exerts a greater force, in proportion, as the line of draught passes near the fulcrum, * If the plane, on which a carriage moves, and the line of draught be both horizontal, the advantage, for surmounting an immovable obstacle of a given height, is as the square root of the radius of the wheel.—See Playfair’s Outlines of JVatural Philosophy, vol. i. p. 103. t See the article. Limit of Bulk, p. 48. BROAD WHEELS. 15 which is in his hind feet. 3. If a horse draws obliquely upward) a part of his force is employed in lessening the pressure on the ground, and, to answer this purpose most effectually, it has been remarked, that the inclination of the traces, or shafts, ought to be the same with that of a road, upon which the carriage would just descend by its own weight.* According to Dr. Gregory, a power, which moves a sliding body along a horizontal plane, acts with the greatest advantage, as far as friction is concerned, when the line of direction makes an angle of about eigh¬ teen and a half degrees with the plane.f M. Deparcieux states, from experiments with carriages, that the angle, made by the trace with a horizontal line, should be one of fourteen or fifteen degrees. 4. Another reason, for in¬ clining the line of draught, is, that a horse depresses his body, in proportion to the force he is obliged to exert, in order that he may bring his own weight to act more advan¬ tageously upon the load. M. Deparcieux has demon¬ strated, that animals draw througli the medium of their weight, in all our common vehicles ; and this fact becomes obvious, when we consider, that if a horse had no weight, he would be unable to draw, but would simply be raised on his hind feet, by any exertion to advance, while in his harness. In the foregoing considerations, it is necessary to re¬ collect, that the conditions, which enable a horse to exert his greatest force, are not those which promote his greatest velocity, and that the means of increasing his speed are obtained, as in other cases, by the sacrifice of power. When there are four wlieels, the line of draught ought to be directed to a point between the two axletrees, or, rather, to a point directly under the centre of gravity of the load ; and such a line should always pass above the axle of the fore wheels. Broad Wheels .—]Much controversy has existed in re¬ gard to the comparative utility of wheels having a broad, or a narrow, circumference. The disadvantages of broad wheels are, that they are heavier than narrow ones, that ♦ Young’s Natural I’hilosopliy, vol. i. p. 216. t Treatise on .Mecttanics, vol. ii, p. 18. 10 ARTS OF LOCOMOTION. they are more expensive, and that they include in their path a greater number of stones, or projecting obstacles. Their advantages are, that they pass more easily over ruts and holes, and that, in soft and sandy roads, they sink to a smaller depth.* But the great benefit which results from broad wheels is of an indirect kind, and arises from the improvement of the roads, which takes place under their use. They tend to prevent deep and narrow ruts, and act as rollers, in levelling the surface. Form of Wheels .—If roads were, in all cases, level and smooth, wheels should be made exactly cylindrical, or with all their spokes parallel to the same plane. But, since the unequal surface of most roads exposes carriages to frequent and sudden changes of position, it is found advantageous to make the wheels a little conical, or, as it is commonly termed, dishing^ so that the spokes may all diverge, with their extremities from the carriage. In this case, whenever the carriage is thrown into an inclined position, and the centre of gravity shifted towards one wheel, the spokes on the under side of that wheel, become more nearly vertical, and are in a more advantageous position to sustain the pressure. This will be seen in Fig. 94, on the opposite page. In muddy roads, there is a convenience attending the dished wheel, in having its circumference further from the body of the carriage, than that of a straight wheel, upon the same hubb,f would be. Some disadvantages, at the same time, attend upon this form of the wheel^ the principal of which is, the increase of friction which it occasions. A conical wheel, if left to itself, tends to travel in a circle, round a point, where the apex of the cone would be situated. If it is obliged to advance in a straight line, it has a degree of lateral motion and friction, which increases in proportion as it deviates from the cylindrical form. In common cases, a slight * The latter advantage, however, is of a more equivocal kind than appears at first view ; for although they sink less deeply, they displace more earth in sinking to the same depth. Still, however, the advan¬ tage, upon calculation, remains on the side of the broad wheel. t This word, instead of nave, is so generally used in this country, that, jt would be a useless refinement to avoid it. The same is true of th9 word factory for manufactory, and also of many mechanical terms. AXLETREES.-SPRINGS, ETC. 17 degree of the dishing form is best, but it should never be carried to such an extent, as to create much friction, or endanger the bending of the spokes. In the annexed figure, (94,) A represents the cylindri¬ cal, and B the dished, form of the wheel. Fig. 94. B Jlxletrees .—When wheels are perfectly upright, the ends of the axles should be cylindrical; but, in dished wheels, they are made conical, and inclined downward, so as to make their under surface horizontal. In this case, the wheels spread most at top, and the lower spokes are most nearly vertical. The ends of the axle tree are often inclined a little forward, which arrangement causes the wheels to run inward, and prevents them from pressing on the linch-pin. The friction, however, is increased. In some locomotive carriages, the axle is fixed to both wheels, and turns with them. This mode of connexion causes great strain and friction, whenever the path is in any other than a straight line, from the necessity, which IS produced, that the wheels should keep pace with each otlier, in their revolutions. — The efiect of suspending a carriage on springs is, to equalize the motion, by causing every change to be more gradually communicated to it, and to obviate shocks, by converting percussion into pressure. Springs are not only useful for the convenience of passengers, but they also diminish the labor of draught; for, whenever a wheel strikes a stone, it rises against the pressure of the spring, in many cases, without materially disturbing the load ; wdiereas, without the spring, the load, or a part of it, must rise with every jolt of the wheel, and will resist this change of place, with a degree of inertia proportionate to the weight and the suddenness of the percussion, o# 18 ARTS OF LOCOMOTION. Hence, springs are highly useful, in baggage wagons, and other vehicles, used for heavy transportation.* Attaching of Horses .—Horses draw most advantage¬ ously, when they are either single, or harnessed abreast of each other. When two horses draw side by side, they are equally near to the load, and have the same line of traction. If their traces are attached, as is frequently done, to hooks on the ends of a crossbar, which, in its turn, is connected to the carriage by a staple, projecting behind, a compensation will be thus made for any difference in the strength, or activity, of the animals. In Fig. 95, the cen- Fig. 95. tre, E, upon which the bar moves, is considerably behind the points of attachment, A and B. Hence, when one end falls back, so that the arm, AB, assumes the position, CD, the foremost horse will have the disadvantage of acting by a lever equal only to EF, while the other horse acts by a lever equal to EC. In the narrow streets of cities, a custom has arisen of harnessing draught horses before each other, in a single line, probably for the sake of room, and the convenience of the driver. But, in this situation, only the shaft horse has an advantageous line of draught. The remaining horses draw nearly in a horizontal line, and, of course, at a disadvantage. Besides this, the foremost horses, being attached to the ends of the shafts, do not act directly upon the load, but expend a part of their force Fig. 96. * See a paper by Mr. Gilbert, in Brande's Journal, vol. xix. HIGHWAYS.—ROADS.-PAVEMENTS. 19 in vertical pressure, upon the back of the shaft horse, which is increased in drays, sleds, and all low carriages. This will be seen by inspecting Fig. 96, where it is obvious, that the line of draught of the first horse cannot become direct, without crippling down the shaft horse. The best mode of remedying this difficulty, would apparently be, to attach the traces of the forward horse to a strong hook, project¬ ing downward from the end of each shaft, so as to bring the traces into the proper line of traction, by directing them more nearly towards the centre of the wheels. It is true, that the shaft horse derives a certain degree of mechani¬ cal advantage from vertical pressure, like that which would result from an increase of his weight. Yet this, although useful in short exertions, is not so, when continued through a day’s fatigue. HIGHWAYS. Roads. —Roads, intended for the passage of wheel-car¬ riages, are made more level, and of harder materials, than the rest of the ground. In roads, the travel on which does not authorize great expense, natural materials alone are em¬ ployed, of which the best are hard gravel and very small stones. The surface of roads should be nearly flat, with gutters at the sides, to facilitate the running off of water. If the surface is made too convex, it throws the weight of the load unequally upon one wheel, and also that of the horses on one side, whenever the carriage takes the side of the road. Hence, drivers prefer to take the middle, or top, of the road, and, by pursuing the same track, occasion deep ruts. The prevention of ruts is best effected by flat and solid roads, and by the use of broad wheels. It would also be further effected, if a greater variety could be intro¬ duced in the width of carriages. Embankments at the sides, to keep the earth from sliding down, are best made, by piling sods upon each other, like bricks, with the grassy surface at right angles with the surface of the bank. But stone walls are preferable for this purpose, when the ma¬ terial can be readily obtained. Pavements .—Pavements are stone coverings of the ground, chiefly employed in populous cities, and the most 20 ARTS OF LOCOMOTION. frequented roads. Among us, they are made of pebbles, of a roundish form, gathered from the sea-beach. They should consist of the hardest kinds of stone, such as gran¬ ite, sienite, &c. If flat stones are used, they require to be artificially roughened, to give secure foothold to horses. In Milan, and some other places, tracks for wheels are made of smooth stones, while the rest of the way is paved with small, or rough, stones.* The advantage of a good pavement consists, not only in its durability, but in the facility with which transportation on it is effected. Horses draw more easily on a pavement, than on a common road, because no part of their power is lost, in changing the form of the surface. The disadvan¬ tages of pavements consist in their noise, and in the wear which they occasion of the shoes of horses, and tires of wheels. They should never be made of pebbles so large as to produce much jolting, by the breadth of the interstices.f Wooden Pavements, made of hexagonal blocks of wood, have been introduced in some of our cities. They have been found more free from dust and noise than other pave¬ ments. They are placed with the grain of the wood per¬ pendicular to the ground, to prevent splintering, and give better foothold. The most hard and durable woods are best; but the cheaper kinds are more used, for economy. J)IcMain Roads .—The system of road-making, which takes its name from Mr. McAdam, combines the advan¬ tages of the pavement and gravel road. The McAdam roads are made entirely of hard stones, such as granite, flint, &c., broken up, with hammers, into small pieces, not exceeding an inch in diameter. These fragments are spread upon the ground, to the depth of from six to ten inches. At first, the roads thus made are heavy, and la- * The streets of many of the ancient cities were paved, as those of Rome, Pompeii, &c. But the streets of London were not paved in the eleventh century, nor those of Paris in the twelfth. t Mr Telford has constructed, in England, a kind of paved road, in which the foundation consists of a pavement of rough stones and frag¬ ments, having their points upward. These are covered with very small stone fragments, and gravel, for the depth of four inches, the whole of which, when rammed down and consolidated, forms a hard, smooth, and durable, road. BRIDGES.-WOODEN BRIDGES. 21 borious to pass ; but, in time, the stones become consol¬ idated, and form a mass of great hardness, smoothness, and permanency. From the manner in which the stones overlap each other, each stone, at the surface, may be considered as the apex of a pyramid, so that it cannot be driven downward, without carrying before it a base of, perhaps, a foot square, as will be seen by Fig. 97. The Fig. 97. stones become partly pulverized, by the action of carriage wheels, and partly imbedded in the earth beneath them. The consolidation seems to be owing to the angular shape of the fragments, which prevents them from rolling in their beds, after the insterstices between them are filled. Mr. McAdam advises, that no other material should be added to the broken stones, apparently with a view to prevent the use of clay and chalk, which abound in England. It appears, however, that a little clean gravel, spread upon the stones, causes them to consolidate more quickly, and has the good effect of excluding the light street dirt, which, otherwise, never fails to become incorporated, in large quantities, among the stones. BRIDGES. The construction of small bridges is a simple process, while that of large ones is, under certain circumstances, extremely difficult, owing to the fact, that the strength of materials does not increase in proportion to their weight, and that there are limits, beyond which no structure of the kind could be carried, and withstand its own gravity. Bridges differ, in their construction, and in the materials of which they are composed. The principal varieties are the following. 1. Wooden Bridges. —These, when built over shal- 22 ARTS OF LOCOMOTION. low and sluggish streams, are usually supported upon piles, driven into the mud, at short distances, or upon frames of timber. But, in deep and powerful currents, it is ne¬ cessary to support them on strong stone piers, and abut¬ ments, built at as great a distance as practicable from each other. The bridge, between these piers, consists of a stiff frame of carpentry, so constructed, with reference to its material, that it may act as one piece, and may not bend, or break, with its own weight, and any additional load, to which it may be exposed. When this frame is straight, the upper part is compressed, by the weight of the whole, while the lower part is extended, like the tie- beam of a roof. But the strongest wooden bridges are made with curved ribs, which rise above the abutments, in the manner of an arch, and are not subjected to a lon¬ gitudinal strain, by extension. These ribs are commonly connected and strengthened with diagonal braces, keys, bolts, and straps of iron. The flooring of the bridge may be either laid above them, or suspended, by trussing, un¬ derneath them. Wooden bridges are common in this country, and some of them are of large size. One of the most remarkable is the upper Schuylkill bridge, at Phil¬ adelphia, which consists of a single arch, the span of which is three hundred and forty feet. 2. Stone Bridges. —These, for the most part, consist of regular arches, built upon stone piers, constructed in the water, or upon abutments at the banks. Above the arches is made a level, or sloping, road. From the nature of the material, these are the most durable kind of bridges ; and many are now standing, which were built by the an¬ cient Romans. Several of the stone bridges across the Thames, at London, are distinguished for elegance and strength. The stone piers, on which bridges are support¬ ed, require to be of great solidity ; especially, when ex¬ posed to rapid currents, or to floating ice. Piers are usually built with their greatest length in the direction of the stream, and with their extremities pointed or curved, so as to divide the water, and allow it to glide easily past them. In building piers, it is often necessary to exclude the water, hy means of a coffer-dam. This is a temporary CAST-IRON BRIDGES, ETC. 23 enclosure, formed by a double wall of piles and planks, having their interval filled with clay. The interior space is made dry by pumping, and kept so, till the structure is finished. 3. Cast Iron Bridges .—These have been constructed in England out of blocks, or frames, of cast-iron, so shap¬ ed, as to fit into each other, and, collectively, to form ribs and arches. These bridges possess great strength, but are liable to be disturbed by the expansion and contrac¬ tion of the metal with heat and cold. 4. Suspension Bridges .—In these, the flooring, or main body of the bridge, is supported, on strong iron chains, or rods, hanging in the form of an inverted arch, from one point of support to another. The points of support are the tops of strong pillars, or small towers, erected for the purpose. Over these pillars, the chain passes, and is attached, at each extremity of the bridge, to rocks, or massive frames of iron, firmly secured under ground. The great advantage of suspension bi’idges con¬ sists in their stability of equilibrium, in consequence of which, a smaller amount of materials is necessary for their construction, than for that of any other bridge. If a sus¬ pension bridge be shaken, or thrown out of equilibrium, it returns, by its weight, to its proper place ; whereas the reverse happens in bridges which are built above the level of their supporters. One of the most remarkable suspen¬ sion bridges, is that over the Menai strait, on the coast of Wales, the span of which, or rather the water-way, is five hundred feet, and the distance between the points of support, or centre of the piers, five hundred and sixty feet. It is suspended by four wrought-iron cables, which pass over rollers, on the tops of the pillars, and are fixed to iron frames, under ground, which are kept down by masonry. 5. Floating Bridges .—Upon deep and sluggish water, stationary rafts of timber are sometimes employed, ex¬ tending from one shore to another, and covered with planks, so as to form a passable bridge. In military op¬ erations, temporary bridges are often formed by planks laid upon boats, pontoons, and other buoyant supporters. 24 ARTS OF LOCOMOTION. RAIL-ROADS. In the best constructed public roads, a great amount of power is expended, in overcoming the disadvantages which are inseparable from their construction, and the nature of their materials. The chief loss of power de¬ pends on the continual change of form, which carriages occasion in roads, by the crushing of stones, cutting of ruts, and other displacements of the material of which the road is made ; which processes serve to consume power, without forwarding the progress of the carriage. The object of a rail-road is to furnish a hard, smooth, and unchanging, surface, for wheels to run upon. These surfaces, in most cases, consist of parallel rails of iron, raised a little above the general level of the ground, and having a gravelled road between the rails, so that the rail¬ road combines the advantages of good foothold for horses, where it is necessary to use them, and of smooth, hard, surfaces, for the wheels to roll upon. The wheels are made smooth and true, and guides, or flanges, to prevent them from slipping off, are affixed, either to the wheels, or to the rails,—most commonly, to the former. Rail-roads are a modern invention, and their greatest improvements have been made within the present century. In comparing the effect of a rail-road with that of a com¬ mon turnpike-road, a saving is made, according to Mr. Tredgold,* of seven eighths of the power ; one horse on a rail-road producing as much effect, as eight horses on a turnpike-road. In the effect produced by a given power, the rail-road is about a mean between the turnpike-road and a canal, when the rate is about three miles per hour ; but, when greater speed is desirable, the rail-road may equal the canal in effect, and even greatly surpass it. In the Winter season, when canals are liable to be frozen, rail-roads, if kept clear from snow and ice, may be al¬ ways passable. In the construction of rail-roads, it is desirable that they should be made as level as possible. For this purpose, the road is first graded, by digging down the more ele- * Treatise on Rail-roads and Carriages, p. 3. EDGE RAII.-WAT. 25 vated parts, and raising those which are depressed. Hills are usually passed through by deep cuts; and, in some in¬ stances, perforated by tunnels^ or hollow passages. Val- lies and marshes are raised by embankments of earth, and streams are crossed by wooden bridges, or by viaducts ot stone, constructed with arches of regular masonry The earliest rail-roads appear to have been constructed of wood only. But, at the present day, iron is employed in all rails from which durability is expected. In some cities, tracks of hewn stone are laid for wheels, in the streets ; but these are seldom executed with sufficient ac¬ curacy, to deserve the name of rail-ways. Of the iron rail-road, there are three principal varieties. 1. The Edge rail. 2. The Tram road. 3. The Single rail. Edge Rail-icay .—In this species, which is now prefer¬ red to all others, and is, indeed, the only one no^v much in use, the rails are laid with the edge upward, and the carriage is retained upon them by a Jlange, or projecting edge, attached to the wheels, instead of the rail. These rails were originally made of cast-iron, about three feet long, and four or five inches deep in the middle, the out¬ line being curved on the under side, to produce equality of strength. Fig. 98, represents a side-view of the old cast-iron rail-way. The ends of the rails are received in a piece of cast-iron, called a chair, and these chairs are affixed to large blocks of stone, or logs of wood, called sleepers, which are previously placed in the ground, upon a proper level. Fig. 99, on the next page, is a section, or end view’, of the rail-road, together with the w heels of a carriage, and the tiange which serves to guide them. Rails are now’ almost universally made of wrought-iron. As this material is costly, when employed alone, it is some¬ times used in thin bars, as a covering to wooden rails, par¬ ticularly in this Country, where timber is plenty, and iron rr. 8 XII. AHTS OF LOCOMOTIOIt- ilC) Fig. 99. expensive.But the most common rails are of solid iron, rolled out in lengths of several yards, the edges, espec¬ ially the upper, being straight, and thicker than the other parts. Wrought-iron rails have the advantage of being longer, and, therefore, reducing the number of joints ; a circumstance which greatly increases the strength, as well as smoothness, of the road. Mr. Trautwine has published, in the Franklin Journal, the following transverse sections of eight varieties of par¬ allel rails, employed on different rail-roads in the United States. They are drawm to a scale of one fourth the full ♦ The durability of this combination of wood and iron, remains to be settled by longer experience. It must be greatly inferior to that of iron alone. TRAMS.-SINGLTi RAILS. size, and accompanied by a statement of the weights, per lineal yard. Weights. No. 1. Columbia and Philadelphia, per yard, A\\ lbs. u 2 33 “ 3. Germantown and Norristown, “ 39 “ “ 4. Camden and Amboy, “ 39^ “ “ 5. Boston and Providence, “ 54 “ “ G. Wilmington and Susquehanna, “ 40 “ “ 7. Alleghany Portage, “ 40 “ “ 8. Boston and Providence, “ 40 “ Tram-roads .—Tram-roads are flat rails, made usually of cast-iron, with an elevated edge, or flange, on one side, to guide the wheels of carriages in their path. Tram rails are weaker than edge rails, when made of the same amount of material, and it is sometimes necessary to strengthen them with ribs underneath. They are capa¬ ble of being used for ordinary wheel carriages, but the introduction of wheels which are not perfectly smooth, is always injurious to the road. Tram-roads are more lia¬ ble to be covered with dirt, than rails of other kinds, and are now little used. Single Rail .—Carriages may be made to run upon a single rail, by elevating the rail from the ground, and sus¬ pending the load beneath it. In Mr. Palmer’s rail-way, the rail is about three feet above the surface of the ground, and is supported by j)illars, placed at distances of about nine feet from each other. The carriage con¬ sists of two receptacles, or boxes, suspended, one on each side of the rail, by an iron frame, and having two wheels placed one before the other. The rims of the wheels are concave, and fit the convex surface of the rail ; and the centre of gravity of the carriage, whether loaded or empty, is so far below the upper edge of the rail, that the receptacles hang in equilibrium, and will bear a con¬ siderable inequality of load without inconvenience, owing to the change of fulcrum, allowed by the breadth of the rail, which is about four inches. 'I’he alleged advantages of the single rail are, that it is more free from lateral fric¬ tion than the other kinds of rail-way, and that, being high- ARTS OF LOCOMOTION. 28 er from the ground, it is less liable to be covered vrith dust and gravel; and, lastly, that it is more economical, the construction of one rail being less expensive than of two. It has not, however, been much introduced into use. Passings, or Sidings. —When the amount of travel on a rail-road is very great, it becomes necessary that the road should be double, one set of tracks being provided for carriages moving in each direction. Where there is less travel, a single road is sufficient, if it be provided with double places, called sidings, for carriages to pass each other, at convenient distances. The siding, or pas¬ sing place, is a short length of additional track, laid by the side of a line of rail-way, and connected with it, at each extremity, by suitable curves, the rails being constructed and disposed in such a manner, that the carriages can either proceed along the main line, or turn into the sid¬ ing, as may be required. To accomplish this, the portion of rails, forming the junction of the siding with the main line, is made mova¬ ble, so as to join either track-way. This portion is term¬ ed a switch, and the points where one rail crosses an¬ other, are termed crossing points. These last are gener¬ ally fixed or immovable ; suitable grooves being left, on their surface, for the passage of the flanges of the carriage wheels on either track-way. The Turn-plate, or Turn-table, is a contrivance for re¬ moving rail-way carriages from one line of rails to another. They are, generally, made for crossings at right angles with each other, but can be adapted to any angle that may be required. They consist of an iron framing, upon which iron gratings, or wood plankings, are laid, thereby forming a table, or platform, two pairs of rails being fixed on the surface of the same, crossing each other at right angles. This platform turns upon a centre pivot, which rests upon another iron frame, set on masonry, friction rollers being inserted between them, at the extreme edges of the table. Curves. —The term curve is applied to a sudden bend, in a line of road, canal, or rail-way. Curves, upon rail¬ ways of less than three fourths of a mile radius, should be PROPELLING POWER.-LOCOMOTIVES. 29 avoided, as the centrifugal force, arising upon them, has a tendency to throw the train off the rails. They also pro¬ duce an injurious amount of friction, which wastes pow¬ er, and wears the flanges of the wheels. When the rail-way crosees a public road, it is made to pass at a lower level than the common surface, and is protected from carriage wheels, by an elevated edging of wood, or stone ; bridges are preferred, whenever the situa¬ tion permits them to be made. Rail-ways require to be free from dirt, which greatly increases the resistance. Mr. Palmer found, upon a tram-road, that it required nine¬ teen per cent, more power to draw the same carriages when the rails were slightly covered with dust, than when they were swept clean. The edge rail, however, being convex on its upper surface, retains but little dust. Propelling Power .—Horses were originally employed for drawing loads upon rail-ways, a horse being supposed capable of drawing eight times as much, as upon a com¬ mon road. But Locomotive steam-engines are now gen¬ erally employed upon rail-ways, of any considerable length. They were, at first, made to propel carriages, by means of a toothed wheel, which acted upon a rack at¬ tached to one of the rails ; but, at the present day, they are made to act by the friction, only, of the carriage wheels upon the plain rail. These engines are alwtiys made of high pressure, since those of low pressure are rendered too heavy, by the weight of the water necessary for con¬ densation. Great improv^ements have lately been made in the construction of locomotive engines, in consequence of which, they have been enabled to attain the extraordi¬ nary speed Qf thirty or forty, and, in some short experi¬ ments, even of seventy, miles, per hour. (See Steam Engine.)* Locomotive Engines differ considerably from other steam-engines, in their mode of construction ; and numer¬ ous modifications are found necessary, to render the ma¬ chine suitable for a rapid transit, the principal of which are the combination of the engine and boiler in one, and a contrivance for the rapid generation of steam. * Franklin Journal, xix. page 407, New Series. 3 * 30 ARTS OF LOCOMOTION. It became necessary, to form the boiler of much smaller dimensions, in proportion to its power, than was before customary, and to reduce the size of the cylinders. A greater degree of strength was also required, in securing the several parts of the framing togetlier, in order to ren¬ der the whole proof against the sudden shocks and strains, to which it is subjected. Locomotives were in a very imperfect state, previous to the opening of the Liverpool and Manchester rail-way, having merely one flue, passing through the boiler, and returned again to the fire-box, at which end the chimney was situated. A greater velocity than eight miles an hour could never be attained by them, owing to the small ex¬ tent of evaporating surface. They did not possess above one quarter the power of the present locomotives. The directors of that rail-way, having, in the year 1829, offered a premium of five hundred pounds for the best locomotive engine, the first stimulus was given to the subject. The Rocket engine, by Mr. G. Stevenson, prov¬ ed successful in obtaining this premium. In the boiler of this engine, lubes were introduced, for the first time, which greatly increased the evaporating powers of the engine ; and, although locomotives have since been con¬ siderably modified, yet this has formed the basis of all the great improvements, which have taken place. A descrip¬ tion of it will be given, under the head of Steam Engine. Mr. Stevenson’s engine weighed only four and a half tons, and the evaporating surface was three times the ex¬ tent of that in the former engines, which weighed up¬ wards of seven and a half tons. It attained a speed of twenty-nine miles an hour, and an average vel^icity of four¬ teen and a half miles an hour. It was soon after found, that, by constructing engines of greater size, with increased evaporating pow’ers, ample amends would be made for the additional weight. Heavier engines were introduced on the Liverpool and Manchester rail-way ; and the loco¬ motives, in general use, at the present time, w^eigh from nine to thirteen tons. The power of a modern locomo¬ tive engine, having twelve-inch cylinders, and an eighteen- I STATIONART ENGINES. SI inch stroke of piston, is computed at about thirty-eight or forty horse power, at high velocities, and seventy or eigh¬ ty liorse power, at a slow rate of speed. The rapid generation of steam, in these locomotives, is owing to the great number of tubes, and to their thin¬ ness, whereby a large surface of water receives its heat quickly, through a thin partition. An advantage is sup¬ posed to be derived from the final escape of the steam, which is discharged into the chimney. Various improvements have been introduced into the locomotive engine, one of which consists in the use of six wheels, instead of four. In this country, many en¬ gines are constructed with six wheels, the first four of which are united by their axles, so as to form a kind of separate carriage, which is made to support one end of the locomotive. This carriage turns on a central bolt, like the fore axle of a wagon. It has the advantage, tliat the pressure is distributed more equally, and that the wheels accommodate themselves better, to curvatures of the road. Stationary Engines are used to draw up loads where tlie ascent is too steep for locomotives to ascend. Where the declivity of the road is great, loaded carriages sometimes descend, by their own gravity, and, at the same lime, draw up the empty ones, by means of pullies. To prevent carriages from acquiring too great a velocity, in descending, a crooked lever, called a brake, or convoy, is applied to the surface of the wheels, so as to retard them by its friction.* When loaded carriages are trans¬ ferred from one part of the road to another, of greater elevation, they are either drawn up an inclined plane, with ixjpes, by horses, or stationary engines ; or, in some cases, they may be lifted perpendicularly, by pullies. This meth¬ od, however, is seldom practised. * A retarding friction is produced, when necessary, in mountainous countries, upon common roads, by chaining one of the wheels, when the carriage goes down hill, so as to prevent its turning. The same effect is produced, in a safer manner, by placing a wooden shoe, like a runner, under one of the wheels. 22 ARTS OF LOCOMOTION. CANALS. Canals are artificial channels for water, cut for the pur¬ pose of admitting inland navigation. The great utility of canals, in facilitating transportation, has caused them to be constructed in all ages. The canals of the ancients were chiefly made on one level, so as to form merely artificial rivers, or creeks. Those of the moderns, by means of locks, are carried, indiscriminately, over ground which is depressed, or elevated. In level tracts of country, if the earth is of suitable character, canals are easily made. But, in loose and crumbling soils, in undulating, rocky, and mountainous, tracts, and in those wliioli are intersected by large streams, their construction becomes expensive and difficult. To surmount these difficulties, loose soils are defended with firmer materials, vallies are passed by embankments, hills are penetrated by deep cuttings or tunnels, rivers are crossed with aqueducts, and declivities are ascended and descended by locks. In order that wa¬ ter may not be wanting in any part of the canal, a supply is ensured at the highest level, and this gradually passes off through the locks, to the lowest. The streams which furnish the water at this, and otlier, points, are called feeders. Embankments .—Canals are dug with sloping sides, to prevent the banks from caving in. The boats being, in almost all cases, drawn by horses, a firm, uninterrupted, towing path is formed on one of the banks. The banks are liable, in time, to become indented and washed away, by the constant agitation of the water, occasioned by the passage of boats. To prevent this, they are sometimes secured, by driving close rows of stakes against the banks ; but, the only effectual protection is found in walling the banks with stone. When the canal crosses a section of country, the surface of which is lower than the intended surface of the water, the canal is raised to the proper level, by means of embankments. These are artificial banks, or dykes, made of such materials as will not be liable to leak, and of such form and strength, that they will not be broken by the pressure of the water. The AQUEDUCTS.-TUNNELS. 33 surface of these banks is of a sloping form, and is secured by sodding, and, in some instances, by piles, or stone walls. Where the nature of the earth renders leakage probable, it is common to cover the bottom and sides of the canal with a lining of puddle, which is formed from loam, or clay, and gravel, worked up with water. For additional security, a trench is dug, in each bank, to a greater depth than the bottom of the canal, and filled with puddle. It sometimes happens, that the embankments act as a dam, to prevent the land, on one side of the canal, from being properly drained. In this case, culverts, or sub¬ terranean passages, are constructed underneath the canal, but not communicating with it, to efteck the necessary draining. Culverts are made of brick, or stone, and re¬ quire to be strong and tight. Aqueducts .—When a canal crosses a river, or a deep ravine, it is supported, at the proper level, by an aqueduct. This structure resembles a stone bridge, formed of strong piers and arches, of regular masonry, rendered as tight as possible, with hydraulic cement. Upon the top, a level channel for the water is formed. This is secured with strong and tight walls, on the sides, and lined within by a coating of clay. Room for the towing path must be preserv¬ ed, on one of the sides. In England, aqueducts have sometimes been made of cast-iron. Tunnels .— Tunnels are subterranean passages, most frequently cut through the base of hills, to afford a level water-course for canals. Tunnels are also made for the passage of rail-ways, and, in some cases, of highway-roads. When they are obliged to be cut through solid rock, which is done chiefly by blasting, their formation is difficult; but they require no artificial security for their subsequent protection. But tunnels, which are made in soft earth, re¬ quire to be arched over, for their whole length, with stone, or brick; and, in loose, springy ground, the bottom, like¬ wise, must be defended with an inverted arch. That tun¬ nels may be properly ventilated, especially while digging, sha fts, or vertical passages, are sunk, at proper distances, in which fires are kept burning, to create a current for dis- 34 ARTS OF LOCOMOTION. charging the foul air. One of the most remarkable tun¬ nels is that at Worsley, on the Duke of Bridgewater’s canal, which, with all its branches, is estimated at eigh¬ teen miles in length. Gates and JVeirs .—As all canals are liable to have their banks broken through, during violent rains and fresh¬ ets, it is important to lessen the injury, which results from such accidents, by retaining as much of the water in the canal as possible. To effect this object, safety-gates and slop-gates are placed, at suitable distances from each other, on the canal, so that, by closing them, at any time, in case of accident, the escape of that part of the water, which is beyond them, may be prevented. These gates are some¬ times attached to the sides, and sometimes lie upon the bottom. Certain parts ofthe banks, called Weirs, are made lower than the rest, to discharge the superfluous water, and keep the surface at a proper level. To prevent them from being gullied, or worn away, by the attrition of the water, they are commonly made of stone, or, sometimes, of wood. Locks .—When a canal changes from one level to an¬ other, of different elevation, the place, where the change of level occurs, is commanded by a Lock. Locks are tight, oblong enclosures, in the bed of the canal, fur¬ nished with gates, at each end, which separate the higher, from the lower, parts of the canal. When a boat passes up the canal, the lower gates are opened, and the boat glides into the lock ; after which, the lower gates are shut. A sluice, communicating with the upper part of the canal, is then opened, and the lock rajfldly fills with water, ele¬ vating the boat on its surface. When the lock is filled to the highest water level, the upper gates are opened, and the boat, being now on the level of the upper part of the canal, passes on its way. The reverse of this process is performed, when the boat is descending the canal. Locks are made of stone, or brick, and, sometimes, ol wood. The walls are sometimes erected upon an inverted arch, and also upon piles, if the soil is alluvial, or loose. They are laid with hydraulic cement, and rendered im¬ pervious to water. The gates are commonly double, re- LOCKS. 35 sembling folding doors, turning upon coin-postSy wliich are next the walls. They meet each other, in most instances, at an obtuse angle, and the pressure of the water serves to keep their contact more firm. The hydrostatic pressure, in these cases, being in full force, in a direction perpendic¬ ular to the surface of the gates, has a diflerent action from that of the pressure of gravity, applied to a roof, or simi¬ lar structure, and gives to long gates a greater compara¬ tive disadvantage than to short ones. Cast-iron gates are sometimes used, in England, curved in the form of a hori¬ zontal arch, with their convex side opposed to the water. Valves are small sliding shutters, which admit a stream of \yater, for the purpose of gradually filling, or emptying, the lock, to prevent the shock of suddenly opening the gates. In situations, where there is a scarcity of water, the waste, occasioned by frequently opening the gates, for the passage of boats, is too great for the amount supplied to the canal. In these cases, to economize the water, re¬ servoirs are provided, at different heights, on each side of the lock. The water, in the upper parts of the lock, is discharged into these reservoirs, and only that in the lower parts is sull’ercd to escape into the lower canal. After¬ wards, the water in these reservoirs is used to fill again the lower parts of the lock, and thus, the same water is made use of, a second time. In China, where inland navigation is much practised, it is said there are no locks, but boats are transferred, from one level to another, by means of inclined planes. This method is sometimes practised, in Europe, and it had a zealous advocate in the late Mr. Fulton. To effect this transfer most advantageously, two boats, passing in oppo¬ site directions, are connected together by a chain, passing over a pulley. One boat, in descending the plane, assists, by its weight, to draw’ the other upward. Sometimes, instead of inclined planes, j)erpendicular lifts have been proposed, by which the boats are hoisted directly, by pul- lies, from one level to another, or lowered, in the opposite direction, by the same means. The objection to all these modes exists in the strain, to which the boats are exposed, unsupported by the pressure of the water. Various ex- 36 ARTS OF LOCOMOTION. pedients have been proposed, for altering the level of the water, and transferring boats, by means of large plungers, diving chests, &c.; but none of them, as yet, appear to have been approved in practice.* Fig. too. Boats .—Canal boats are made narrow, for passing each other, and draw water proportioned to the depth of the canal. Their length is limited only by that of the locks. They are drawn by horses, on the tow-path, being kept, by the rudder, from coming in contact with the bank. No species of oars, poles, or paddle-wheels, is allowed, on account of the injury done to the bottoms and banks, by their use. It is said, however, that the steam-engine has, in some cases, been used, without injury to the canal, by causing the paddle-wheels to work in a water passage, or casing, which passes through the boat, above its bottom. Size of Canals .—Canals differ greatly from each other, not only in their length, but their size, and the draught of water which they admit. One of the largest canals, as far as the volume of water is concerned, is the great Dutch canal, which connects the city of Amsterdam with the Helder, on the north coast of Holland. This canal is fifty miles in length, one hundred and twenty-four feet in width, at the surface of the water, thirty-six feet wide, at bottom, and about twenty-one feet deep. It is large enough to permit one frigate to pass another. The Cal¬ edonian canal extends from the Murray Frith, on the eastern coast of Scotland, to Loch Eil, on the western, and admits of the passage of large ships. It is one hun¬ dred and twenty feet wide, at the water surface, and fifty wide, at bottom. The depth of water is twenty feet. The distance, from sea to sea, is about fifty-nine miles, of which thirty-seven and a half is lake navigation, and • Repertory of Arts,.vol3. >. ii. and xxiii. SAILING.-FORM OF A SHIP. 37 twenty-one and a half is cut.* The canal of Languedoc, in France, is sixty-four leagues in length, and connects the Atlantic ocean with the Mediterranean sea. It is sixty-four feet wide, at the surface, and navigable for ves¬ sels of one hundred tons. The great New York, or Erie, canal is three hundred and sixty miles long, and extends from the Hudson river, at Albany, to Lake Erie, at Buffalo. It is forty feet wide, at the surface, twenty-eight feet wide, at bottom, and has four feet depth of water. SAILING. Form of a Ship .—The movement of bodies through water, if performed within certain limits of velocity, is at¬ tended with less resistance than that which takes place in most other modes of transportation. A body, however, of given size, will encounter a greater or less resistance from the water, according to its proportions, and the sort of surface which it opposes to the fluid. In calculating the proper form for a ship, it is necessary to consider the kinds of pressure, to which bodies, moving in fluids, are subject. If we suppose an oblong square box, or paral¬ lelepiped, as ABCD, in Fig. 101, to move through the Fig. 101. water, in the direction of its length, the pressure will be increased before, and diminished behind it, the surface of the water being elevated, at the anterior extremity, and depressed, at the posterior ; an effect which increases, in a high ratio, as the velocity becomes greater. The prin¬ cipal part of the water, which is before the moving body, divides and passes oft' by the sides ; but a certain quantity of what is called dead water is pushed along, in advance of the moving body., nearly in the same manner as if it were *■ Supplement to the Encyclopedia Britannica, and Edinburgh Ency¬ clopedia. II. 4 XII. 38 ARTS OF LOCOMOTION. a part of the body itself. The shape of this dead water, at the surface, is found to be that of an irregular triangle, and hence it becomes advantageous to add to the moving body an extremity, or having nearly the same shape as the dead water, and occupying its place, as in the dot¬ ted line, BED. On the other hand, there occurs, behind the moving body,, a depression of surface, and a- partially empty space, which is also of a triangular, or wedge, form, consisting of the room which the moving body has just left, and into which the water, upon each side, has not yet flow¬ ed. The cavity, which is thus formed, resists the progress of the body, by its negative pressure. Its efl'ect is readily understood, when we consider, that, if the water before the moving body be raised one foot, while the water behind it is depressed one foot, the difference of pressure, upon the two extremities, will be equal to that resulting from two feet. On this account, it is advantageous to add to the moving body a tapering, or wedge-shaped, extremity, be¬ hind, capable of occupying this cavity, and nearly answer¬ ing to it in shape, as represented by the dotted line, AGC. The consequence will be, that the water, which is advanc¬ ing from both sides to fill up the vacuity, will meet the ta¬ pering sides of the vessel soon enough to obviate, or great¬ ly diminish, the negative pressure. The form, produced by this general outline, varied by a proper curvature of the sides and bottom, corresponds nearly to that which is adop¬ ted in the construction of ships, and also to that pur¬ sued by Nature, in the structure of fishes. If a vessel be intended for a fast sailer, its proportionate length, and its sharpness, before and behind, must be increased, since both the positive and negative pressure, and the extent of the dead water and vacant space, will increase with the velocity. Keel and Rudder .—The use of the keel, which is a projecting timber, extending the whole length of the ship’s bottom, is to assist in confining the motion of the ship to its proper direction, and, by its lateral resistance, to dimin¬ ish the disposition to roll, or vibrate, from side to side. The rudder, which is a perpendicular part attached, by braces, resembling hinges, to the stern-post of the vessel, EFFECT OF THE WIND. 39 serves to govern the ship’s course, by altering the relative resistance of its two sides. Thus, while the ship is under way, if the rudder is turned to one side, it receives an impulse from the water on that side, causing the stern to turn towards the opposite side, where no such resistance exists, thus altering the direction of the keel, and the general qgurse of the vessel. Effect of the Wind. —When a ship sails in the same direction as the wind, she is said to be scudding, or sail¬ ing before the wind, and if she had but one sail, it would act with the greatest advantage, when perpendicular, or nearly so, to the wind. When a ship advances against the wind, and endeavors to proceed, in the nearest direction possible, to the point of compass from which the wind blows, she is said to be close-hauled. A large ship will sail against the wind with her keel at an angle of six points with the direction of the wind, and sloops, and smaller vessels, may sail much near er. When a ship is neither sailing before the wind, nor close-hauled, she is said to be sailing large. In this case, her sails are set in an oblique position, between the direction of the wind, and that of the intended course ; as represented in the various plans of vessels in Fig. 102, on page 40, where the direction of the wind is represented by the arrow, and the position of the yards and sails, which is necessary for proceeding on the various points of com¬ pass, is shown by the transverse lines on each plan. The relation of the wind to the course of the vessel is deter¬ mined by the number of points of the compass, between the course she is steering, and the course which she would be steering, if close-hauled. In Fig. 102, the ships, [a and 6,] are close-hauled, and the ships, [c and c?,] the for¬ mer steering east by north, and the latter west by north, have the wind one point large. The ships, [e and /,] one steering east, and the other west, have the wind two points large. In this case, the wind is at right angles with the keel, and is said to be upon the beam. The ships, l^g and /i,] steering southeast, and southwest, have the wind six points large, or, as it is commonly termed, upon the quarter, and this is considered as a very favora- ARTS OF LOCOMOTION. Fig. 102. ble manner of sailing, because all the sails cooperate to increase the ship’s velocity ; whereas, when the wind is directly aft, as in the vessel, [m,] it is partly intercepted by the after sails, and prevented from striking, with its full force, on those which are forward. The force of a wind which strikes obliquely upon the sails, supposing them flat surfaces, is resolvable into two forces, one of which tends to push the vessel ahead, and the other to push her sideways. If the form of the vessel, instead of being oblong, were circular, like a tub, she would move in the direction of the diagonal of a rectangle, representing these two forces, and her course would be at right angles with the position of the sail, or in the direction of the line AB, in Fig. 103. But, owing to the oblong shape of the vessel, and the influence of her keel, it requires about twelve STABILITY OF A SHIP. 41 times as much force to push her sideways, as to push her head foremost.* The oblique impulse, therefore, will j carry her a great distance forward, in the time that she is I drifting a short distance to the leeward, and it is this re- { lative difference of progress, which enables a vessel to I advance, even against the wind. The angular deviation I of a ship’s real course, from her apparent course, upon I which her head is directed, is called the leeicay. In the ! vessel, [Fig. 103,] with the wind blowing in the direction Fig. 103. t , of the arrows, and the sails set as represented, if the ves¬ sel were moving in a rail-way, or unchangeable channel, her course would be BD ; but, in the water, she drifts so much to the leeward, that her real course is BC, and the i angle, CBD, represents the amount of leeway. i Stability of a Ship .—The masts of a ship, wdien acted j upon by the pressure of the wind against the sails, are so j many levers, the tendency of which is, to overset her. I To counteract this tendency, a sufficient weight of ballast, I or cargo, is stowed in the bottom of the hold, to carry the centre of gravity into the lower part of the hull, so that this part will ahvays preponderate, while the relative buoyancy of the upper part causes the vessel to right, as often as her position is disturbed. If the ballast is too light, or is stowed too high in the hold, the vessel is said to be too cranky and rolls more, and cannot carry so much sail, without danger of oversetting. On the other hand, if the ballast is too heavy, and placed too low, the vessel is said to be too stiff, and not only drawls so much water as to impede her velocity, but is liable to have * Robiuaon’s Meclianicol Philosophy, vol. iv. p. 620. 4* 42 ARTS OF LOCOMOTIO:^. her masts endangered, by the shocks which result from the suddenness of her motions. In regard to shape, an increase of the width of a ship increases her stability, but, at the same time, detracts from her power'as a fast sailer. Steam Boats .—Experiments on the propulsion of ves¬ sels, by steam, were made in Europe, and this country, at different times, during the last century ; but the first successful introduction of ste»n navigation, on a large scale, was made in America, by the late Mr. Fulton, about the year 1807. The application of the steam-en¬ gine to navigation, has given to vessels the advantage of greater speed and regularity, in the performance of their passages, without interruption from the changeable, and often adverse, operation of the elements. In the action of the steam-engine, as in that of rowing, a vessel is pro¬ pelled by a succession of impulses, which act against the inertia of the water. A power acting within a boat, whether of men, of horses, or of steam, may be applied to the water, in va¬ rious ways. Some of the principal of these are the fol¬ lowing. 1. A system of oars, or paddles, has been made to act tvith alternating strokes, rising out of water at the end of each stroke. 2. An alternating paddle has been contrived, which is continually immersed, and which folds up, like the foot of a water-fowl, during the backward stroke. 3. It has been proposed to drive a current of air, or a current of water, out at the stern of the vessel. 4. Spiral wheels and water-screws, or \yheels with oblique vanes, like those of a windmill, have been made to turn under water, with their axes parallel to the keel of the vessel. 5. Oblique planes, acting with an alternate, instead of a revolving, stroke, were recom¬ mended by Bernoulli. 6. Paddle-wheels. These, from their simplicity, and advantageous mode of action, have, in common use, superseded all the rest. They consist of paddles, or float-boards, attached to the arms, or spokes, of a wheel, the axis of which is at right angles with the keel. Their common place is on the sides of the boat, as in Fig. 104, on the opposite page. The outline of the float-boards, or paddles, is com- BTEAM-BOATS. 43 Fig. 104. nionly rectangular, though ]Mr. Tredgold recommends that their outer extremity should be parabolic. The best po¬ sition for the paddles is in a plane, passing through the axis of the wheels ; but with this position, they strike the water obliquely, in entering, and lift a considerable quantity, on quitting it; both of which motions occasion loss of pow¬ er. Attempts have been made to correct this disadvant¬ age, by various mechanical arrangements, in which the paddles are made to enter and leave the water perpen¬ dicularly ; but want of simplicity, and objections of vari¬ ous other kinds, have prevented them from coming into use. It has been proposed to fix a series of paddles up¬ on longitudinal chains, passing round wheels, and parallel to each side of the vessel. By this mode, a number of perpendicular paddles would act upon the water at once ; but it will be seen, that, as no more of these paddles can operate usefully, than are sufficient to put the water be¬ tween them into motion, a part of the series will be less useful, than if it acted upon water at rest. In wheels of the common form, it is advantageous to have a double row* of paddles, one outside the other, and so placed, that the paddles of one series shall be opposite the intervals of the other, and thus enter the water successively, and in difierent places.* This plan is the one most generally adopted, in American steam-boats. In Perkins’s propel¬ ling wheel, the paddles are placed obliquely, in regard to the axis of the wheel, and the wheel itself is placed ob- * For examinations of the different propelling powers, see the Edin¬ burgh Encyclopedia, article ‘ Navigation Inland,’ ascribed to Mr. Tel 'ord ; also, Tredgold on the Steam Engine, p. 309. 44 ARTS OP LOCOMOTION. liquely, in regard to the keel of the boat. This arrange ment is such, that the paddles enter and leave the water obliquely, but, at the time of their greatest immersion, they are at right angles with the keel, and in the most favora¬ ble position for propelling the boat. The average speed of a well-constructed steam-boat has been assumed at fourteen miles per hour, and the greatest speed at sixteen miles.* Steam-boats have been considered as best adapted to the navigation of rivers, and straits, or sounds, where the water is comparatively smooth. In the open sea, the vio¬ lence of the \yaves renders the action of the paddle-wheels irregular, and it was, for a long time, thought difficult for them to carry fuel sufficient to supply the engine, during long voyages. The steam-ship Savannah first crossed the Atlantic, in 1819, and was twenty-one days, from land * Mr. W. S. Redfield, of New York, has addressed to Lieutenant Hos- ken, the commander of the Great Western steam-ship, a letter, in which he says : “There is, if I mistake not, some misapprehension prevail¬ ing, both in England and America, in regard to the ordinary, as well as maximum, speed of the best steam-vessels. This is mainly to be as¬ cribed to three causes ; 1st. The erroneous statements which often find their way into newspapers. 2d. To a mistaken estimate of the velo¬ city of the tides and currents. And, 3d, to the erroneous popular esti¬ mate of navigating distances, which, on nearly all internal, or coasting, routes, in both countries, so far as my knowledge extends, are habitu¬ ally overrated. This may explain, on one hand, the extravagant claims to velocity, which are sometimes stated of American steam-boats ; and, on the other hand, may account for the strange incredulity, which has been manifested by Dr. Lardner, and others, not well acquainted with the structure and performances of American steam-boats. 'I'he ac¬ quaintance which I have had with the navigation of the Hudson, by steam, during the last thirteen years, enables me to speak with confi¬ dence on some of the points involved. “ The usual working speed of the best class of steam-boats, on the Hudson, may be estimated at fourteen statute miles per hour, through still water of good depth. That they are not unfrequently run at a lower speed, is freely admitted. But the maximum speed of these boats is, and has been, for several years, equal to about sixteen miles per hour. In regard to the “ admitted four miles per hour tide up the Hudson,” the admission is extremely erroneous. The average advan¬ tage to be realized, in a passage on flood-tide, from New York to Al¬ bany, is not more than one mile and a half per hour, or, at the most, say twelve miles, in a passage to Albany,—equal to about one twelfth of the distance, as performed under the most favorable circumstances ” STEAM-SHIPS.-niVING-BELL. 45 to land, during eighteen of which, only, she was able to use her engine. Steam Skips .'—The difficulties attendant on marine steam navigation, which, but a short time ago, were pro¬ nounced, by some distinguished authorities, to be insur¬ mountable, have been completely overcome by the intro¬ duction, in 1838, of steam-ships of extraordinary size, propelled by engines of great power. The Great West¬ ern, which arrived at New York, from Bristol, in April, 1838, measured, for her extreme length, two hundred and thirty-six feet, and in width, between the outside of the paddle-cases, fifty-eight feet. The British Queen, which followed in the next year, is two hundred and seventy- five feet long, which is stated to be thirty-five feet longer than any ship in the British navy. She has two engines, of two hundred and fifty horse power each. It is now settled, that the passage of the Atlantic may be made, safely and successfully, by vessels of this size, and ac¬ complished, under favorable circumstances, in less than a fortnight. The success attending these experiments has led to the multiplication of ocean-steamers, which are intended to ply upon all the great tracks of commerce, in the civil¬ ized world. The communication between Europe and the United States, as well as that with the West and East Indies, and, indeed, with most of the important sea-ports on the globe, may be considered as hereafter to be per¬ formed, in half the time which was formerly required, and with far greater certainty, in regard to the times of arrival and departure. Of the numerous steam-ships now building, or built, in Great Britain, to ply between that country and foreign ports, some are constructed entirely of iron. Some are of immense size, exceeding that of the British Queen, which has already been mentioned. •> DIVING-BELL. The diving-bell is an inverted vessel, containing air, and used for the purpose of enabling persons to descend, with safety, to great deptlis under water. It is made tight 46 ARTS OF LOCOMOTION. at the top and sides, but is entirely open at bottom. Its principle is the same with that of a gasometer, and may be familiarly illustrated, by immersing an inverted tumbler in a vessel of water. The air cannot escape from the in¬ side of the vessel, being necessitated, by the order of spe¬ cific gravities, to occupy the upper part of the cavity. Diving-bells appear to have been first introduced, in the beginning of the sixteenth century. They were first known as objects of curiosity, only, but have been since applied to the recovery of valuable articles from wrecks, the blasting and mining of rocks, at the bottom of the sea, and the practice of submarine architecture. They may be made of almost any shape ; but the common form has been that of a bell, or hollow cone, made of wooden staves, and strongly bound with hoops, having seats for the occu¬ pants, on the inside. It is suspended with ropes, from a vessel above, and is ballasted with heavy weights at bot¬ tom, which serve to sink it, and to prevent it from turn¬ ing over. More recently, diving-bells have been made of cast-iron. The kind of bell used at Howth, near Dub¬ lin,* is an oblong iron chest, six feet long, four broad, and five high, thicker at bottom than at top, and weighing four tons. It has a seat at each end, and is capable of holding four persons. The upper part is pierced with eight or ten holes, in which are fixed the same number of strong convex glasses, which transmit the light. As the air in the bell becomes contaminated, by breathing, it is renewed, by letting down barrels, or small bells, of fresh air, which is transferred to the large bell ; or else, by keeping up a constant supply, through a pipe, by means of a forcing pump, which is worked by men at the sur¬ face. * Persons who descend in diving-bells often experience a ]>ain in the ears, and a sense of pressure, occasioned by the condensation of the air, within the cavity of the bell. These symptoms gradually pass off, or habit renders the body indifferent to them, so that workmen remain under water, at the depth of twenty feet or more, for seven or eight hours in a day, without detriment to the health. * Edinburgh Philosophical Jouraal, vol. v. p. 8. SUBMARINE NAVIGATION, 47 Submarine JV'avigation .—A machine was invented, during the American Revolution, by Mr Bushnell, of Connecticut, which was capable of containing a person in safety, under water, and of being governed, and steered in any direction, at pleasure. It is described* as being a hollow vessel, of a spheroidal form, composed of curved pieces of oak, fitted together, and bound with iron hoops, the seams being caulked, and covered with tar, to render them tight. A top, or head, was closely fitted to the ves¬ sel, and served the purpose of a door. In this were in¬ serted several strong pieces of glass, to admit the light. The machine contained air enough to render it buoyant, and to support respiration. A quantity of lead was at¬ tached to the bottom, for ballast. The vessel was made to sink, by admitting water, and to rise, by detaching a part of the leaden ballast, or by expelling water with a forcing pump. It was propelled horizontally, by means of revolving oars, placed obliquely, like the sails of a wind¬ mill, on an axis which entered the boat through a light collar, or water-joint, and was turned with a crank with¬ in. A rudder was also employed, for steering the vessel. When fresh air was required, the vessel rose to the sur¬ face, and took in air through apertures at the top. The intention of this machine was, to convey a magazine of powder under ships of war, for the purpose of blowing them up. Several experiments were made with it, which, though unsuccessful in their object, nevertheless proved the practicability of this species of locomotion. The late Mr. Fulton made various experiments on sub¬ marine navigation, in a boat large enough to contain sev¬ eral persons, furnished with masts and sails, so as to be capable of proceeding at the surface of the water, and, also, of plunging, when required, below the surface.f While under water, its motions were governed by two machines, one of which caused it to advance horizontal¬ ly, while the other regulated its ascent and descent, its depth below the surface being known, by the pressure on a barometer. A supply of fresh air was carried down in ♦ Silliman’s Journal, vol. ii. p. 94. t See Colden’s Life of Fulton, 8vo. New York, 1810. 48 arts of locomotion. the boat, condensed into a strong copper globe, by wh)ch the air of the boat was replaced, when it became unfit for respiration. Mr. Fulton’s object was the destruction of ships of war, by bringing underneath them an explosive engine, called a torpedo. AEROSTATION. Balloon .—A Balloon is a sphere, or bag, formed of some light material, such as silk, and rendered impervi¬ ous to the air, by covering it with elastic varnish. It is filled with a gaseous fluid, lighter than the surrounding atmospheric air, and has a car suspended, at the bottom. If the specific gravity of the whole mass is less than that of an equal bulk of the atmospheric air, which surrounds it, the balloon will ascend into the atmosphere, and re¬ main suspended, until, by the escape of its gas, or other means, it becomes heavier than the surrounding air, when it will again descend. Balloons were invented in France, by the Montgolfiers, about 1782. Those which were first employed by them were filled with common air, rarefied by heat ; but these required, that a fire should be constantly kept burning beneath them, to keep them afloat. Hydrogen gas was afterwards employed ; and this fluid, being permanently about fourteen times less dense than common air, is, undoubtedly, the best material for aeros tation. Carburetted hydrogen, though heavier than hy¬ drogen, has also been employed, of late, on account of its cheapness, being furnished, in large quantities, at the man¬ ufactories of illuminating gas. Balloons are made, by sewing together pieces of silk, the shape of which corresponds to that of the part includ¬ ed by two meridians of the artificial globe. They have also been made of linen, and of paper. They are var¬ nished with a solution of elastic gum, to render them tight. A net-work is thrown over the top of the balloon, to which is attached, by strings, a car of wicker-wmrk, un¬ derneath the balloon. The whole is kept down, by a sufficient quantity of ballast, and ascends into the atmo¬ sphere, when a part of the ballast is thrown over. It is made to descend again, by suffering a part of the gas to escape through a valve, provided for the purpose. PARACHUTE. 49 The regulation of the ascent and descent of balloons is the extent of control, which has been hitherto obtained over them. All attempts to guide or propel them, by means of wings, sails, oars, &c., have hitherto failed, and the machine can only proceed at the mercy of the winds. The small degree of buoyancy, which balloons possess, does not permit them to carry sufficient weight of mate¬ rial, to furnish the medium of an adequate propelling force. By taking advantage, however, of favorable winds, voy¬ ages have been made in them to the distance of three hundred miles ; and persons have ascended to the height of twenty thousand feet, and upwards. The velocity of balloons varies with that of the wind, but has, in some instances, amounted to the rate of seventy miles an hour.* Parachute .—The danger, which attends falling from great heights, is in consequence of the continual acceler¬ ation of velocity, which falling bodies experience. When, however, the resistance of the atmosphere becomes equal to the force of gravity, the motion is no longer acceler¬ ated, but becomes uniform. A parachute is an appen¬ dage to a balloon, formed somewhat like an umbrella, and is designed to break the force of a fall, by means of the large surface which it opposes, in its progress, to the at¬ mosphere. It is made of silk or canvass, and is placed miderneath the balloon, having the car suspended from it by cords. When the balloon is at any height in the air, the parachute may be detached from it, and will imme¬ diately fall with the car, to the ground. But the resistance of so large a surface to the atmosphere, causes the fall to ho gradual and easy, so that a jierson may descend with a parachute, in safely, from the greatest heights. The size of the parachute, employed by M. Garnerin, and with which he descended from a height of two thousand feet, at Paris, in 1797, was twenty-five feet in diameter. The parachute was folded up, at the beginning of the fall, * M. Gay-Lussac, on the 6th of September, 1804, ascended twen ty-three thousand and one hundred feet above Paris. M. Garnerin, September 21st, 1827, passed, in seven hours and a half, from Pari* to Mount Tonnere, a distance of three hundred miles. This voyag# was performed in the night, and during a storm. xir. 50 ELEMENTS OF MACHINERV. but soon expanded itself, by the resistance of the atmo¬ sphere. The only inconvenience, which was experienced, arose from a violent oscillating motion. Works of Reference. — Brewster’s Edition of Ferguson’s Lectures on Mechanics, &c. 2 vols. 8vo. 1823 ;—ANsxiCE.on Wheel Carriages ;— Edgeworth, on Roads and Carriages, 8vo. ;— Depar- ciEUx sur letirage des chevaux, in the Mem. de I'Acad. Paris, 17C0 ; — Young’s Lectures on Natural Pliilosophy ;—Me Ad am, on roads, Svo. 1823 ; —Blunt and Stevenson’s Civil Engineer, fol. 1834, &c. ;— Parnell, Treatise on Roads, 8vo. 1833 ; —Tredgold, on Rail Roads, 8vo. 1825 ;—Wood, on Rail Roads, 8vo. 1825 ;— Strickland’s Reports on Canals, Rail Roads, &c., oblong fol. Phil ad., 1820 ;—Article Canal, in Rees’ Cyclopedia, written by Mr. J. Farey ; Articles Navigation Inland, Railwaj', Bridges, Aeronautics, &c., in the Edinburgh Encyclopedia ;— Chapman, on Canal Naviga¬ tion, 4to. 1797 ;—Fulton, on Canal Navigation, 4to. 1796 ; —Smea- ton’s Reports, 3 vols. 8vo. 1812 ;— Prony, Architecture Hydrau- lique, 2 tom. 4to. 1790 ; —Belidor, Architecture Hydraulique, 4 tom. 4to. 1750 ;— De Cessart, Travaux Hydrauliques, 2 tom. 4to. 1808 ;—Reports to the House of Commons on Roads, Steam Boats, &c., 1822, &c. ;—Article Seamanship, in the Encyclopedia Brittani- ca, by Prof. Robinson ;— Dupin, Voyage dans la Grand Bretagne, 6 vols. 8vo. with plates, fol. 1825. CHAPTER XV. 1 ELEMENTS OF MACHINERY. Machines, Motion. Rotary, or Circular, Motion, Band Wheels, Rag Wheels, Toothed Wheels, Spiral Gear, Bevel Gear, Crown Wheels, Universal Joint, Perpetual Screw, Brush Wheels, Ratchet Wheel, Distant Rotary Motion, Change of Velocity, Fusee. Al¬ ternate, or Reciprocating, Motion, Cams, Crank, Parallel Motion, Sun and Planet Wheel, Inclined Wheel, Epicycloidal Wheel, Rack and Segment, Rack and Pinion, Belt and Segment, Scapements. Continued Rectilinear Motion, Band, Rack, Universal Lever, Screw, Change of Direction, Toggle Joint. Of Engaging and Dis¬ engaging Machinery. Of Equalizing Motion, Governor, Fly Wheel. Friction. Remarks. tMachines .—By a machine, may be understood a com- tination of mechanical powers, adapted to vary the di¬ rection, application, and intensity, of a moving force, so MOTION.-ROTART, OR CIRCULAR, MOTION. ’51 as to produce a given result. The advantage which ma¬ chines possess, over common manual labor, is generally that of increasing, or improving, the product of an oper¬ ation. This end they accomplish, by enabling us to ap- j)ly a common force, more advantageously, or to employ the most powerful force, derived from natural agents, with precision and efficacy. By the aid of machinery, any number of instruments, or operative parts, may be made to move in concert, in every [lossible direction, with any degree of velocity, and to reciprocate with each other in jierfect harmony, so that complex operations are per¬ formed by them, with a precision which often exceeds the skill of the most expert artist. Motion .—The motion which takes place in machines is, for the most part, either rotary or reciprocating. A rotary motion is that, in which the moving parts revolve round an axis, as in a wheel, a crank, or a Hy. A recip¬ rocating, or alternate, motion is that, in which a body re¬ traces its own path, or moves alternately backward and forward, in the same track, which may be curved, as in the beam of a steam-engine, or rectilinear, as in the pis¬ ton. Most compound machines possess both these kinds of motion, or varieties derived from them ; and the dif¬ ferent ways of producing and communicating them, in the requisite times and places, constitute a principal subject of attention with machinists. ROTARY, OR CIRCULAR, MOTION. When it is intended that one wheel, or axle, shall pro¬ pel another, various contrivances are adopted, to connect the propelling part with that which is to be moved. The mode of connexion is varied, according to the distance, the relative velocity required, and the direction in which motion is to be communicated. Band Wheels .—If two wheels be connected by a belt, or band, passing round their circumferences, they will move simultaneously, provided the friction of the band is sufficient to prevent it from slipping. When a round cord is used, any degree of friction may be produced, by receiving the cord in a sharp groove, at the edge of the 62 ELEMENTS OP MACniNERY. wheel. But the stiffness of cords forms, in many cases, an objection to their use. When a strap, or flat band, is used, its friction may be increased, by increasing its width. The surface at the circumference of a wheel, or drum, which carries a flat band, should not be exactly cylindri¬ cal, but a little convex in which case, if the band in¬ clines to slip off, at either side, it returns again, by the tightening of its inner edge, as may be seen in a turner’s lathe. When wheels are connected, in the shortest man¬ ner, by a band, as in Fig. 105, they move in the same Fig. 105. Fig. 106. direction. If the band be crossed, as in Fig. 106, they will move in opposite directions. Wheels, whose axes are situated in different planes, may turn each other, if the band be sufficiently long. If no slipping were to take place in the band, wheels of equal size would move with equal velocity, and those of different sizes, with velocities inversely proportionate to their respective circumferen¬ ces. But, since the band is liable to yield or slide, some¬ what, during the revolution, the velocity of the driven wheel is, commonly, a little less, in proportion, than that of the w’heel which drives it. Rag Wheels .—Where it is necessary that the veloci¬ ties should be exactly proportionate, also, where great resistance is to be overcome, chains of various kinds are substituted, by passing them round wheels, in the place of belts and ropes. These chains lay hold upon pins, or enter into notches, on the circumference of the wheels, so as to cause them to turn simultaneously. Such wheels are denominated rag-wheels, and have a uniform relative TOOTHED WHEELS. 53 velocity. [Fig. 107.] They are used in locomotive steam- engines, chain water-wheels, &c. Fig. 107. Toothed Wheels. —Toothed wheels afibrd a more re¬ gular and effectual mode of communicating rotary motion, than any other kind of connecting mechanism. They move, of necessity, in opposite directions, and their rela¬ tive velocity is inversely proportionate to their number of teeth. Thus, if a wheel having forty teeth drives another of ten teeth, the second will make four revolutions, while the first makes one. The connexion of one toothed wheel wu'th another is called gear., or gearing ; and, when both wheels, with their teeth, are in the direction of the same plane, it is called spur-gearing. It is desirable, in tooth¬ ed wheels, as far as possible, to diminish friction, and to produce uniformity of force and motion. A uniform mo¬ tion may be produced, if the form of the acting face of the teeth be a curve of the epicycloidal kind ; the outline of the teeth of one wheel being the curve which would be described, by ibe revolution of a curve upon a given circle, while the outline of the teeth of the other wheel is described, by the same curve rolling within the circle. It may also be produced, if the teeth of one wheel be straight, circular, or of any regular figure, whatever ; pro¬ vided the teeth of the other wheel be of a figure, com¬ pounded of that figure and of an epicycloid.* Of two wheels, whicli are unequal in size, the larger is called the wheel, and the smaller, the pinion. The act¬ ing portions of the wheel are called teeth ; and, of the * For investigations relating to the teeth of wheels, see Camus, on the Teeth of Wheels, translated, London, 8vo. 1806 ;—Buchanan, on Mill Work, chap. i. &c. ;—Brewster’s Ferguson’s Lectures, vol. ii. 5 . 119 ;—Gregory’s Mechanics, vol. ii. p. 451 ;—also, a Treatise, by Ir. Blake, in Silliman’s Journal, vol. vii. p. 86. 64 ELEMENTS OF MACHINERY. pinion, more commonly, leaves. The name of lanterns is given to pinions with two heads, connected by cylin¬ drical teeth, or trundles. In Fig. 108, the line, joining Fig. 108. the centres, B and F, of the wheel and pinion, is called the line of centres, and, when this line is divided into two parts, FA and BA, which are to each other, as the number of leaves in the pinion is to the number of teeth in the wheel, BA is called the primitive radius* of the wheel, and FA, the primitive radius of the pinion ; while the lines, or distances, Ff and Bb, are called the true radii. The circles, XAX and R AR, are called the primitive cir¬ cumferences, and, by w^orkmen, the pitch lines. Friction, to a certain extent, cannot be avoided, in teeth of the common kind, whose acting faces are at right angles with the plane of the wheels, to which they belong. It may, however, be much diminished, by making tlie teeth as small and as numerous, as is consistent with their strength ; for the quantity of friction necessarily increases, with the distance of the point of contact from the line of centres. • Called the proportional radius, by Buchanan SFIRAL GEAR. 55 Spiral Gear .—In common cases, the teeth of wheels are cut across the circumference, in a direction parallel to the axis. In the spiral gear, now much used in cotton mills, in this country, the teeth are cut obliquely, so that, if continued, they would pass round the axis, like the threads of a screw. In consequence of this disposition, the teeth come in contact only in the line of centres, and thus operate without friction. [Fig. 109.] The action Fig. 109. of these wheels, it is true, is compounded of two forces, one of which acts in the direction of the plane of the wheel, and the other in the direction of its axis. The latter force occasions a degree of friction, which, being expended at the end of the axle, may be regarded as in¬ considerable. The remaining force goes to produce ro¬ tary motion. The spiral gearing has been applied to clock-work, and has the peculiarity, that it’ admits of a smaller pinion than any other gearing. Thus, if a very small cylinder have a spiral groove so cut in it, as to extend once round its circumference, it will perform one revolution for every tooth of the wheel which drives it. The groove may be cut indefinitely near to the centre of the pinion, or cylin¬ der, without weakening it so much as would happen in other forms of the pinion.* *The spiral gear has been used at Waltham, Mass., and elsewhere, for about fifteen years, and is coniiuoiily considered, here,as the inven¬ tion of Mr. White. Something ^alogous to it, under the name of Inclined Plane Wheels, was pnbiished in London, by Mr. T. Shel¬ drake, in 1811. 55 ELEMENTS OF MACHINERT. Bevel Gear .—When wheels are not situated in the same plane, but form an angle with each other, the spur¬ gearing, already described, is changed for teeth of a dif¬ ferent description. In this case, the bevel gearing is commonly employed, consisting of wheels, which are frusta of cones, having their teeth cut obliquely, and con¬ verging toward the point, where the apex of the cone would be situated. According as the relative magnitude of the wheels varies, the angle of the bevel must be dif¬ ferent, so that the velocities of the wheels may be in the same proportion, at both ends of their oblique sides, or faces. For this purpose, the faces of all the teeth must be directed to the point, where the axes of the two wheels would meet. The bevel gearing is shown in Fig. 110, and Fig. 116. Fig. liO. Crown Wheels .—^Circular motion is also communicat¬ ed, at right angles, by means of teeth or cogs, situated parallel to the axis of the wheel. Wheels, thus formed, are denominated crown., or contrale, wheels. They act either upon a common pinion, or upon a lantern. The cr':>wn-wheel is represented in Fig. 111. It is less in use than the bevel-gear, before described, having more friction. Fig. 111. 1 UNIVERSAL JOINT.-PERPETUAL SCREW. 57 I Universal Joint .—The contrivance called Hooke’s universal joint, is sometimes used, instead of wheels, to communicate circular motion in an oblique direction. It consists of two shafts, or axes, each terminating in a semicircle, and connected together by means of a cross, upon which each semicircle is hinged. [Fig. 112.] It is Fig. 112. obvious, that when one shaft is turned, the other must re¬ volve likewise ; and this will be the case, whenever the angle, by which one shaft deviates from the direction of the other, does not exceed forty degrees. By means of a double universal joint, circular.motion may be com¬ municated, at an angle of from fifty to ninety degrees. Perpetual Screio .—The perpetual, or endless, screw, sometimes called worm^ by mechanics, is made use of to convey circular motion from an axle to a toothed wheel, situated in the direction of the same plane with the axle. The relative velocity of a wheel driven by a screw is very slow ; for, if the screw have only a single thread, the wheel will advance the breadth of one tooth, only, for each 58; ELEMENTS OF MACHINERY. revolution of the screw. This mechanism is of great use in producing an equable slow motion, in machinery, and also, in increasing mechanical power. [Fig. 113.] The motion may be reversed, or conveyed from the wheel to the screw, if the obliquity of the threads be sufficiently increased. A spiral wheel and a toothed wheel may be made to turn, with equal velocity, or any desired propor¬ tion of velocity, by the construction represented in Fig. 7 (4. A, is a wheel, seen edgeways, its axis being BC. Fig. 114. D A Its circumference is furnished with spiral ridges, which, as the wheel turns, cause the pinion, D, to revolve in the plane of the axis, BC. Brush Wheels .—In light machinery, wheels sometimes turn each other by means of bristles, or brushes, fixed to their circumference. They may, also, communicate cir¬ cular motion, by friction only. In this case, the surface brought in contact is formed of the end-grain of wood, or it is covered >vilh leather, or some other elastic substance,, and the two wheels are pressed together, to increase the friction. Ratchet Wheel .—The ratchet, or detent, wheel is in¬ tended to prevent motion in one direction, while it per¬ mits it in another. For this purpose, the teeth are cut with their faces inclining in one direction, and a small lever, or catch, is so placed, as to enter the indentations, and stop the wheel, if it turns backward, but slides ovei the teeth, without obstructing them, if it moves forward. [Fig. 115.] Ratchet-wheels are generally employed to DISTANT ROTARY MOTION. 59 prevent a weight, raised by a machine, from descending, and to obviate other retrograde movements. Fig. 115. Distant Rotary J\Iotion .—When it is required to trans¬ mit circular motion to a distance, for example, from one extremity, or story, of a building, to another, various meth¬ ods are employed. The most common is, by band-wheels, or drums, connected by leather belts of the requisite length. This mode is considered most economical. When a precise velocity is required, a rolling shaft, geared at both ends, as in Fig. 116, is to be preferred. A double crank. Fig. 116. having its two parts at right angles with each other, and connected with a similar crank, by stiff rods, or bars, an¬ swers the same purpose. [Fig. 117.] If triple cranks are Fig. 117. used, cords will serve, instead of bars, for connection, be¬ cause, in this case, some part of the first crank will always be in a situation to draw the second, and a rigid medium will not be necessary. 60 ELEMENTS OF MACHINERY. Change of Velocity .—It is sometimes necessary, that a machine should be propelled with a velocity which is not equable, but which continually changes, in a given ratio. This happens in cotton-mills, where it is neces¬ sary that the speed of certain parts of the machinery should continually decrease, from the beginning to the end of an operation. To efiect this object, two cones, or conical drums, are used, having their larger diameters in opposite directions. They are connected by a belt, which is so governed, by proper mechanism, that it is gradually moved from one extremity of the cones to the other, thus acting upon circles of different diameter, causing a con¬ tinual change of velocity in the driven cone, with relation to that which drives it. [Fig. 118.] Fig. 118. A change of speed is also effected, by a decreasing series of toothed wheels, placed, in the order of their size, upon a common axis, and fixed. A corresponding series, in an inverted order, are placed upon another axis, and not fixed, but capable of revolving about the axis, like loose pullies. The axis of this second series is made hollow, and contains a movable rod, which has a tooth, project¬ ing through a longitudinal slit in one side of the axis. This tooth serves to lock any one of the wheels, by entering a notch, cut for its reception. Only one wheel, however, can be locked at a time, the others remaining loose, so that the axis will revolve with a velocity, which is due to the relative size of the particular wheel which is locked, and of the wheel which drives it. By successively lock¬ ing the different wheels, an increase, or decrease, of speed is obtained.* [Fig. 119.] * A mechanism of this kind is used in the cotton factory at New¬ ton, Massachusetts, and there is one, nearly similar, in Bramah’s plan¬ ing machine. « * 9 ^ CHANGE OF VELOCITT. Cl Another mode of changing speed is produced, by a large, and small, wheel, placed at right angles with eacli other, and acting by friction only. The edge of the smaller wheel is kept in close contact with the disc, or flat surface, of the larger wheel, so that the smaller wheel will revolve faster, or slower, according to the distance, at which it is kept from the centre of the larger wheel. The distance may be varied at pleasure. [Fig. 120.] Fig. 120. It is sometimes requisite that a wheel, or axis, should move with different velocity, in different parts of a single revolution, as in orreries, &c. This may be effected, by an eccentric crown-wheel, acting on a long pinion, as in Fig. 121. II. 6 XII. 62 ELEMENTS OF MACHINERY. Fig. 121. It may also be accomplished in a different way, by a cone, furnished with spiral line of teeth, acting on another cone, the position of which is reversed. ^ Fusee.—In the preceding arrangements for changing velocity, there is a corresponding change of force, which is in an inverse ratio to the change of velocity. They may, therefore, be employed for varying force, as well as speed. The fusee of a common watch is a contriv¬ ance, adapted to this purpose. When a watch is recent¬ ly wound up, the spring, which propels it, is in the state of greatest tension. As this spring relaxes, or uncoils itself, its power decreases, and, in order to correct this inequal¬ ity, the chain, through which it acts, is wound upon a spi¬ ral fusee. The fusee, B, is an axis, surrounded by a spiral groove, the distance of the groove from the axis being made to increase gradually, from the top to the bottom, so that, in proportion as the force of the spring is diminished, it may act on a longer lever. The general outline of the fusee must be nearly such, that its thickness, at any part, may diminish, in the same proportion as it becomes more distant from the point, at which the force would cease altogether, the general curve being that of a hyperbole ; but the workmen have, in general, no other rule, than that T)f habitual estimation. [Fig. 122.] Fig. 122. ALTERNATE, OR RECIPROCATING, MOTION. This name is applied to movements which take place continually, backwards and forwards, in the same path. An alternate motion may take place about a centre, in which case, the moving parts will describe arcs of circles, as in a tilt-hammer, or the beam of a steam-engine ; or it may be confined by guides, so as to pursue a rectilinear paUi, as in the saw of a saw-mill. In most complex ma- CAMS. 63 chines, both rotary and reciprocating motions occur, and tliese motions are converted into each other, by any of the following contrivances. Cams .—If the axis of a wheel be situated in any other point than its centre, the wheel, thus rendered eccentric^ may produce, by its revolution, an alternate motion in any part exposed to its action. Circles, hearts, ellipses, parts of circles, and projecting parts of various forms, are made to produce alternate motion, by continually altering the distance of some movable part of the machine, from the axis about which they revolve. Such projecting parts are called cams.* In the various forms which are shown in the figures, the part, removed by the cam, is supposed lo return, by its own gravity, or by some other power, so ^ as to keep up the alternate motion. In the circular centric cam, or whe6l, [Fig. 123,] the sliding, or recipro-^ eating, part, AB, will ascend and descend, with an easy motion, being never at rest, unless at the instant of chang¬ ing its direction. Eccentric wheels, if surrounded by a hoop, as at H, in PI. IX. perform the same office as cranks. In the semicircular cam, [Fig. 124,] the recipro¬ cating part will remain at rest, on the periphery of the cam, during half the revolution, but, in the remaining half, it will approach the axis, and return. In the quadrant cam, [Fig. 125,] the reciprocating part will remain at rest, on the periphery, during the first quarter of the revolution ; Fig. 123. Fig. 124. Fig. 125. Fig. 126. Fig. 127. A A A A A * This word is spelt cam, camm, and camb, by different writer*. In French caiM. — Borgnit. 64 ELEMENTS OF MACHINERY during the second, it will descend to the axis ; during the third, it will be at rest upon the axis ; and during the fourth, it will return to its original situation. The narrow cam, [Fig. 126,] causes the reciprocating part to rise and fall, in one half the revolution, and to remain at rest, on the axis, during the other half. In these figures, the angles of the cams are made sharp, for the sake of demonstration ; but, in practice, they are generally rounded, to produce more gradual changes of motion. The elliptical cam, [Fig. 127,] causes two alternate movements for each revolution ; and the triple cam, in Fig. 12S, applied to a tilt, or trip, Fig. 128. hammer, causes three strokes for one revolution. In thit case, the cams are called loipers, and it is common to accelerate the reciprocal motion, by adding to the action of gravitation, the elastic force of a spring, or by the re¬ coil of the handle from a fixed obstacle. A cam, in the form of a heart, called a lieart-ioheel, is much used in cotton-mills, to cause a regular ascent and descent of the rail on which the spindles are situated.* When an easy rnotion is desired, as in most large ma¬ chinery, the acting outline of the cam should be curved ; but, to produce a sudden stroke, it should be straight. The nuniber of cams may be indefinitely multiplied, if a rapid, or vibrating movement, is required. This is, in effect, done, when the teeth of a wheel act upon a spring, or weight, as in a watchman’s rattle, or in the feeder of a grist-mill. * For an investigation of the curves proper for different caras^d wipers, see Brewster’s edition of Ferguson’s Mechanics, vol. ii. p. 126, &c. For producing an easy and uniform motion, spiral, epicycloidal, and other curves, are requisite ; but, for abrupt, forcible, motions, such as occur in tilt-hammers, curves of equal action are to be avoided. CRANK.-PARALLEL MOTION* 65 Crank .—The common crank affords one of the simp¬ lest and most useful methods, for changing circular into alternate motion, and vice versa. The single crank, [Fig. 129,] can only be used upon the end of an axis. The bell-crank, [Fig. 130,] may be used in any part of an axis. The double crank, [Fig. 131,] produces two alternate Fig. 129. I'm. 130. Fig. 131. n motions, reciprocating with each other. The alterna¬ ting parts, in all these cases, are attached to the crank by connecting rods, or by some of the kinds of mechan¬ ism, hereafter described. The motion, produced by cranks, is easy and gradual, being most rapid, in the mid¬ dle of the stroke, and gradually retarded, toward the extremes ; so that shocks and jolts, in the moving ma¬ chinery, are diminished, or wholly prevented, by their use. JMolion .—The name of parallel motions is giv- ^^''^'^rilo those arrangements,j,vhich convert circular motion, whether continued or alternate, into alternate rectilinear motion, and vice versa. 'I'hus, the beam of a steam-en¬ gine moves in circular arcs, while the piston moves in right lines. They cannot, therefore, 4)6 rigidly connect¬ ed together, without doing violence to the machine ; and it becomes necessary to convert one movement into the other, by the intervention of proper mechanism. A mov¬ able parallelogram is principally used, for this purpose, and will be described under the head of Steam Engine. A similar contrivance, of a more simple form, is shown in Fig. 132. CD, is a rod, moving back and forwards, in a right line. Every point of junction is a hinge, or joint. 6 * 66 ELEMENTS OF MACHINERT. Fig. 132. GE, is a rod, movable about E, as a centre ; and EH, a rod of the same length, movable about F, as a centre ; these centres being equally distant from the path of CD. GH, is a bar, connecting these two rods, and having the rod, CD, attached, by a joint, to its centre. When the whole is set in motion, the joint, G, will describe the cir¬ cular arc, IK, and the joint, H, will describe the circular arc, GH, while the joint, C, will pursue an intermediate, or rectilinear, course. Various other methods are practised, to insure a rectili¬ near motion, though most of them are attended with great Fig. 133. i t £UN AND PDANET WHEEL.- 67 er friction than that last described. Thus, the alternating part is often confined to a rectilinear path, by sliding in grooves, guides, or holes, or between friction wheels ; a connecting rod uniting the straight and circular motions, as in the last instance. In Cartwright’s steam-engine, the straight movement of the piston is secured, by con¬ necting it with two cranks, acting in opposition to each other, and having their axles geared together by wheels, as represented in Fig. 133, on page 66. The connecting rod may be dispensed with, if a trans¬ verse groove, or slit, be cut in the alternating part, of a length equal to the diameter of the crank’s revolution; as in Fig. 134. The end of the crank, seen at [a,] in its Fig. 134. c D revolution, traverses the whole length of this groove, which is cut in the crossbar, AB, while the main bar, CD, has an alternate motion in the straight path to which it is con¬ fined. As the space of ascent, or descent, of the bar, CD, is always equal to the versed sine of the arc described by the crank, the motion of the bar will be accelerated, towards the middle of its oscillations, and retarded, to- w’ards the extremes. A more equal motion can be pro¬ duced, if desired, by substituting for the straight groove, a curvilinear groove, somewhat like the figure od ; but this method is attended with much friction, and little use. Sun and Planet Wheel .—The mechanism which bears this name, was invented by Mr. Watt, to convert 68 ELEMENTS OF MACHINERT. reciprocating into circular motion, in the steam-errgine ; llie use of the crank, for tills purpose, being, at one time, secured by patent to another individual. In Fig. 135, a Fig. 135. view is given of the sun and planet wheel. A, is the end of a beam, having a reciprocating motion. B, is the fly¬ wheel of the engine, to which a rotary motion is to be communicated. Upon the axis of this fly-wheel, a small toothed wheel is firmly fixed. A second toothed wheel is connected to the first, by a loose crank, so as to be capable of revolving freely about it. This second wdieel is firmly fixed upon the end of a connecting rod, which is attached, by a joint, to the beam of the engine. The two wheels being in gear, it is obvious, that as the beam. A, rises and falls, the second wheel, with the assistance of the fly, will revolve quite round the first; and, if the number of teeth be equal, the first, or sun-wheel, must perform two rotations on its axis, while the second, or planet-wheel, revolves once round it. The necessity of this will be more obvious, when w'e consider, that, if one tooth of the planet-wheel, were con¬ nected by a joint to one tooth of the sun-wheel, it would act as a simple crank, and cause one revolution. But an additional revolution is also necessary, because, during the circuit, all the teeth of the planet-wheel must act l.NCLIXED WHEEL.-EPICVCLOIDAL WHEEL. 09 upon those of the sun-wheel, thus turning it round, as in common wheel-work. Fig. 136. C E JJ T D F Inclined Wheel .—In Fig. 136, AB, is a wheel, placed obliquely on its axis, CD. The edge, or periphery, of this wheel, is received in a notch, at B, of a sliding bar, EF. As the wheel revolves, the bar, EF, will move up and down once, during each revolution. This reciprocal motion may be indefinitely varied, by bending the edge of the wheel into different curves and angles. Epicycloidal Wheel .—A very beautiful method of con¬ verting circular into alternate motion, or alternate into cir¬ cular, is shown in Fig 137. AB is a fixed ring, or wheel. Fig. 137. toothed on its inner side. C, is a toothed wheel, of half the diameter of the ring, revolving about the centre of the ring. While this revolution of the wheel, C, is taking place, 70 ELEMENTS OP MACHINERY. any point, whatever, on its circumference, will describe a straight line, or will pass and rej)ass tlirough a diameter of the circle, once, during eacli revolution. This is an elegant application of the law, that, if a circle rolls on the inside of another of twice its diameter, the epicycloid de¬ scribed is a straight line. In practice, a piston, rod, or other recipt-ocating part, may be attached to any point onjhd^circumference of the wheel, C. Rack and Segment .—If an alternating motion is requir¬ ed, the velocity of which shall be always equal, a rack is best adapted to produce this effect. In Fig. 138, AB, Fig. 138. IS a parallelogram, having a rack on two opposite sides. C, is a half wheel, toothed on its curved side, and having its centre equally distant from the two racks. It is ob¬ vious, from inspection, that, as this half wheel revolves, its teeth will act successively upon the two racks, and cause the parallelogram to move back and forwards, with a uni¬ form motion. The change, however, from one direction to the other, will be nearly instantaneous, so that this plan will only answer in machinery which is very light, or of slow motion. The teeth of the half wheel must cover somewhat less than half a circle, that they may not become engaged in one rack, before they are disengaged from the o^r. r Rack and Pinion .—Another contrivance, which ren- d^the change more gradual, is represented in Fig. 139. AB, is a double rack, with circular ends, fixed to a beam, capable of moving in the direction of its length. The rack is driven by a pinion, P, which is capable of moving up and down in a groove, [wn,] cut in the cross-piece. When the pinion has moved the rack and beam, until it comes to BELT AND SEGMENT.-SCAPEMENTS. 71 Fig. 139. the end, B, the projecting piece [«] meets the spring, [ 5 ,] and the rack is pressed against the pinion. The pinion, then working in the circular end of the rack, will be forced down the groove, [mn,] until it works in the lower side of the rack, and moves the beam back in the opposite direction; and, in this Wciy, the motion is continued. The motion of the pinion in the groove will be diminished, if, instead of a double rack, we use a single row of pins, which are parallel to the axis of the pinion, as in some of the ma¬ chines, called mangles. Belt and Segment .—An alternate circular motion is converted into an alternate rectilinear motion, in fire-en¬ gines, dressing-machines, &c., by a belt, or chain, fasten¬ ed to each end of a segment, or other portion of a wheel. The two belts pass by each other, and are attached to the opposite ends of an alternating part. When the segment turns, in either direction, it draws after it the alternating part, in a straight line. [Fig. 140.] Fig. 140. _ Scapements. — In clocks and watches, an alternating motion is produced m the pendulum and balance-wheel, 72 ELEMENTS OF MACHINERY. by means of the mechanism called a scapeyient. In the more simple scapements, two teeth, called pallets, are made to vibrate on a common axis. They are connect¬ ed with a toothed wheel, in such a manner, that one pallet enters between the teeth of the wheel, whenever the other is thrown out of their reach. As the wheel revolves, its teeth successively impinge against one or the other of these pallets, and, by causing them successively to escape, communicate to their axis a vibrating, or alternate, motion. The crutch scapement, [Fig. 141,] is an arch, situated in the same plane with the scape-wheel, and parallel to the plane in which the pendulum vibrates. Its pallets suc¬ cessively enter and escape from the teeth of the wheel, and receive from it a vibrating motion. In the old, or com¬ mon, watch scapement, [Fig. 142,] a contrate, or crown, wheel is used as the scape-wheel, and the pallets [« and 6 ] are placed upon the axis of the balance-wheel, so as to meet the teeth, successively, on opposite sides of the cir¬ cumference of the scape-wheel. A variety of other more complicated forms of the scapement are also in use. Fig. 141. Fig. 142. BAND. RACK. 73 CONTINUED RECTILINEAR MOTION. A long-continued rectilinear motion is not to be pro¬ duced in the parts of a machine, except so far as it par¬ takes of the nature of a rotary, or a reciprocating, motion. Thus, a band, passing round pullies, is a modification of rotary motion, and a rack, which is obliged to return at intervals, has a reciprocating motion. But, to a certain extent, the motions of both may be regarded as contin¬ uously rectilinear. Band .—If it is required to produce motion, in a right line, which shall be always in one direction, as, for exam¬ ple, in the feeding parts of machines, a band, passing round pullies or drums, is the method most commonly practised, as in Fig. 105. If a precise velocity is required, the band may be perforated with holes, and received upon short pins, at the circumference of the wheels ; or the rag-wheel and chain, represented in Fig. 107, may be substituted. Rack .—If a slow rectilinear motion is required only for limited times, such a mechanism may be used, as wall permit the moving part to retrace its own path, at inter¬ vals, and regain its original situation. [Fig. 143.] A rack, which is a straight bar, having teeth on one side, will move in this manner, if it be acted on by a toothed wheel, or by a perpetual screw. If the thread of a perpetual screw be formed of different obliquity, in different parts of its circumference, the progressive velocity of the rack will be unequal, instead of being uniform. And, if a part of the thread be in a plane, at right angles with the axis of the screw, the rack will be at rest, while that part of the screw’ revolves in contact wdth it. II. t xii. 74 ELEMENTS OF MACHlNERT. I Universal Lever. —A rack is also propelled, by means bf a catch, or dog, connected with some part of the ma¬ chine, which has an alternating motion. The catch caus¬ es the rack to advance, the length of one tooth, at each stroke of the alternating part. The universal lever, some¬ times called the lever of La Garousse, consists of a bar moving upon a centre, and having a movable catch, or hook, attached to each side, and acting upon the oblique teeth of a double rack, or of a ratchet-wheel, so that the alternating motion of the bar causes a progressive motion of the rack, or wheel. [Fig. 144.] Fig. 144. Screw. —A common screw is often made use of, to produce rectilinear movements, when the motion is in¬ tended to be very slow, or when great power is required. Change of Direction. —A change, from one path, or direction, to another, forming an angle with it, may be produced, by several of the mechanical powers. Thus, a cord, passing over a pulley, may change a perpendicular to a horizontal motion, as at P, [Fig. 159,] or to one at any other angle required. A bent lever, like that repre¬ sented by y z, in PI. III., produces the same effect, pro¬ vided the moving parts are confined, by guides, to their respective paths. An inclined plane, also, if it moves through the length of one side of a parallelogram, will cause another body to move through the length of the contiguous side, at right angles. This method, however, is attended with much friction. Toggle Joint. —The knee-joint, commonly called, in OF F.NCiAGlNG AND DISKNGAGING MACHINERY. 75 .this country, toggle-joint^ affords a very useful mode of converting velocity into power, the motion produced be¬ ing nearly at right angles with the direction of the force. Its operation is seen in the iron joints which are used, to uphold the tops of chaises. It is also introduced into various modifications of the printing press, -in order to obtain the greatest power, at the moment of the impres¬ sion. Jt consists of two rods, or bars, connected by a joint, and increases rapidly in power, as the two rods ap¬ proach to the direction of a straight line.* In Fig. 145, a moving force, applied in the direction CD, acts with great and constantly increasing power, to separate the parts, A and B. Fig. 145. A 1“ OF ENGAGING AND DISENGAGING MACHINERY. y In many cases, particularly where numerous machines arV^piopelled by a common power, it is important to pos¬ sess the means of stopping any one of them, at pleasure, and of restoring its motion, without interfering with the rest. To produce this effect, a great variety of combi nations have been invented, under the name of couplings. These, in most instances, are sliding boxes, which move longitudinally upon shafts or axles, and serve to engage, or lock, a shaft which is at rest, with one which is in mo¬ tion ; so as practically to’convert the two into one, until • .4n investigation of tlie power of this combination, is given by the late Professor Fisher, in Silliinan’s Journal, toI. Hi. p. 320. 76 ELEMENTS OF MACHINERV. they are again unlocked. Couplings are sometimes pro¬ vided with clutches, ox glands, which are projecting teeth, intended to catch on other teeth, or levers, and thus lock the shafts together. Sometimes they have bayonets, or pins, adapted to enter holes. Sometimes, the connexion is produced by friction alone, by pressing together sur¬ faces, which are eitheror conical. Sometimes, also, wheels are thrown into, and out of, gear, which is done, by causing wheels to slide in the direction of their axles, or, in some cases, by elevating and depressing the axle itself. These methods, however, are difficult and un¬ safe. The live and dead pulley afford, perhaps, the sim¬ plest mode of engagement. They consist of two paral¬ lel band-wheels, on the same axle, one of which is fast, and the other loose, or capable of turning without the axle. The band, which communicates the power, is placed upon the loose pulley, when it is desired to stop the machine, and upon the fast pulley, when it is intend¬ ed to set the machine in motion. A common band may, also, be made to admit of motion or rest, according as it is rendered tense, or loose, by a tightening wheel, pressed against its side by a lever. 'v_ OF EQUALIZING MOTION. In most machines, both the moving force, and the re¬ sistance to be overcome, are liable to fluctuations of in¬ tensity, at different times. As such variations influence both the safety and efficiency of machines, it is necessa¬ ry to provide against them, by some appendage, which shall equalize either the supply, or the distribution, of the er. Governor. —The name of governor has been given to ^ingenious piece of mechanism, which has been intro¬ duced, to regulate the supply of steam, in steam-engines, and of water, in water-mills, so as to render the power equable, and proportionate to the resistance to be sur¬ mounted. It is represented in'Fig. 146, on the opposite page. AB, and AC, are two levers, or arms, loaded with heavy balls, at their extremities, B and C, and suspended, by a joint, at A, upon the upper extremity of a revolv- 77 ing shaft, AD. At [a,] is a collar, or sliding box, con¬ nected to the levers, by the rods [a6, and ac,] with joints at their extremities. It follows, that when the weights, B and C, diverge, the collar [a] will move up¬ ward, on the shaft, AD, and vice versa. The governor, thus constructed, is attached to some revolving part of the machine. In this state, if it turns too rapidly, the balls, B and C, move outwards, by their centrifugal force, and draw upward the collar, [a.] If, on the other hand, the speed diminishes, the balls are allowed to subside, and the collar moves down upon the shaft. In the steam-engine, the collar has a circular groove, which receives the end of a forked lever. As the collar rises and falls, this lever turns upon its fulcrum, and acts, remotely, to open or close a throttle-valve, which is placed in the main steam-pipe.* Whenever, therefore, the machine moves too rapidly, the balls recede from the centre, the collar rises, the lever moves the valve, and, by partially closing the pipe, di¬ minishes the quantity of steam admitted from the boiler. If the machint^moves too slowly, tlie reverse takes place, and a larger amount of steam is admitted. in water-wheels, where a greater power is necessary to control the supply of water, the governor is usually connected to the sluice-gate, by the intervention of wheel- work. This may be done in several ways, one of which * For a farther account of the governor, see the article, Steam En. GOVERNOR. Fig. 146. 78 ELEMENTS OF MACHINERY. is as follows. The lower part of the shaft, AD, carries a wheel at D, acting upon two others beneath it, M and N. While the machinery moves with its proper speed, the wheels, M and N, are both unlocked, and turn loosely round their axles, and the gate is stationary. But, when the velocity increases or diminishes, the collar [a] rises or falls, and, by means of a cam, acts upon a lever above it, or upon another below it, so as to lock one of the wheels, M or N, by moving a clutch situated at [d.] These wheels, being upon a common axle, are capable of turning this axle different ways. When, therefore, one wheel is locked to the axle, it acts by turning a perpetual screw, to open the sluice gate. When the other is locked, the axle and the screw turn in the opposite direction, and partially close the gate. The foregoing are some, out of various, modes in which the governor is applied. In windmills, it is so adapted as to increase the feeding, or supply of corn, when the mill goes too fast, and also to vary the distance .of the mill¬ stones from each other, if necessary. It has also been applied to clothe and unclothe the sails, in proportion t^' the strength of the wind. Fly Wheel .—It is an object of great importance, in machines, to have the means of accumulating power, when the moving force is in excess, and of expending it, when the moving force operates more feebly, or the resistance increases. This equalization of motion is obtained, by what is called a fly, which is generally made in the form of a heavy wheel, though, sometimes, in the form of arms, or crossbars, with weights at their extremities. A fly being made to revolve about its axis, keeps up the force, by its own inertia, and distributes it, in all parts of its j'ev- olution. If the moving power slackens, it impels the machine forward ; and if the power tends to move the machine too fast, it keeps it back. Fly-wheels are capable of accumulating power to a great extent. A small force, continually applied to the surface of a heavy revolving wheel, will accelerate its ve¬ locity, till it shall be equal to that of a musket-ball, and its mompntum almost irresistible. Fly-wheels, to act FRICTION. 79 with the greatest efficacy, should be made with the least possible surface, that their motion may not be impeded, by the resistance of the air. They should be made of iron, and, if they cannot be cast in one piece, they should be firmly hooped, or bolted together, that the parts may not separate, by their centrifugal force. Fatal accidents have occurred from the bursting of large stones, used as flies, or as grindstones, in cutlery works, their velocity, and centrifugal force being so great, as to overcome their cohesive attraction, and to project the parts to a distance, with great violence. Beside the modes already described, other methods are employed, to retard and equalize tlie velocity of ma¬ chinery. A kind of fly is used, in music boxes, and in the striking part of clocks, hi which the broad surface of vanes, upon the circumference of a wheel, is made to act against the air, until the resistance becomes equal to the propelling force, so that the velocity can increase no fur¬ ther, but becomes uniform. Pendulums and balances, acted on through the different kinds of scapements, are also means of equalizing motion. . FRICTION. t.i. A part of the force, by which machines are moved, is expended in overcoming their friction. Hence it isdesir- able to obviate, as far as possible, this kind of resistance. Friction is supposed to arise, chiefly, from the roughness and inequality of the surfaces of bodies. No polish can be given to a surface, mechanically, so fine, as to render it perfectly smooth. When surfaces move over each other, a certain force is necessary to disengage the minute asperities of one surface from those of the other, either by causing them to rise over each other, or by bending or breaking them down. Friction is increased, by the roughness of bodies, and, also, by the force with which they are pressed together. But it is very little affected by the extent of the surfaces in contact. It is greatest, at the moment when motion begins. It does not, however, change afterwards as the velocity changes, but continues to retard, with a uniform 80 ELEMENTS OF MACHINERY. force, whether the motion performed be slow, or rapid. There are several points, in regard to friction, upon which writers are not agreed. Friction in machinery is to be diminished, by making the surfaces, which rub upon each other, as smooth as pos¬ sible, and by covering them wdth some unctuous substance. Black lead, in fine powder, is sometimes interposed be¬ tween surfaces, to diminish friction, and soapstone, applied in the same manner, is still more useful. It is supposed, Dy some, that different metals, moving upon each other, occasion less friction, than surfaces of the same metal. But the most important mode of diminishing friction is, to employ a rolling or turning motion, instead of a sliding motion, in all cases where it is practicable ; and, by sim¬ plicity of construction, to avoid all unnecessary contact cf moving surfaces. Remarks. —In the construction of machines, no subject is more deserving of attention, than simplicity of parts and structure. The more complex machines are, the more expensive they are to erect, the more liable to get out of order, and the more difficult to repair. An increased expenditure of power is also occasioned, by their friction. A complex machine may evince great ingenuity on the part of the inventor, and may have cost much labor and science to complete it. Yet it is sure to be superseded^ the moment that a more simple, cheap, or expeditious, way of attaining the same object is discovered. The im¬ provement of the mechanist, or engineer, more frequent¬ ly consists in the simplification of his means, than it does in the construction of complex and difficult pieces of work¬ manship. Works of Reference.—Buchanan, on Mill Work, and other Machinery, 2 vols. 8vo. 1823 ; —Robison’s Mechanical Philosophy, vol. ii. p. 181 ; —Nicholson’s Operative Mechanic, 8vo. 1825 ;— Gregory’s Mechanics, 1826 ;— Brewster’s edition of Ferguson’s Mechanics, 1823 ;— Borgnis, Mechanique Appliquee aux Arts, 4to. Paris, 1818, Tom. 3, Composition dcs Machines ;— Lanz et Bet- TANCOURT, sur la Composition des Machines, Paris, 4to. 1819 ;— Hachette, Traite Elementaire des Machines ;— Leupold, TTie- atrum Machinarum Universale, 7 vols. folio, Leipsic, 1724 to 1774 MOVING FORCES USED IN THE ARTS. 81 CHAPTER XVI. OF THE MOVING FORCES USED IN THE ARTS. Sources of Power, Vehicles of Power. Animal Power, Men, Hors¬ es. Water Power, Overshot Wheel, Chain Wheel, Undershot Wheel, Back Water, Besant’s Wheel, Lambert’s Wheel, Breast Wheel, Horizontal Wheel, Barker’s Mill. Wind Power, Vertical Windmill, Adjustment of Sails, Horizontal Windmill. Steam Pow¬ er, Steam, Applications of Steam, By Condensation, By Generation, By E.xpansion, The Steam Engine, Boiler, Appendages, Engine, Non¬ condensing Engine, Condensing Engines, Description, Expansion En¬ gines, Condenser, Valves, Pistons, Parallel Motion, Locomotive En¬ gine, Power of the Steam Engine, Projected Improvements, Rotative Engines, Use of Steam at High ^Pemperatures, Use of Vapors of Low Temperature, Gas Engines, Steam Carriages, Steam Gun. Gunpowder, Manufacture, Detonation, Force, Properties of a Gun, Blasting, Magnetic Engines. Sources of Power .—It is the office of machines, to re¬ ceive and distribute motion, derived from an external agent, since no machine is capable of generating motion, or moving power, within itself. The sources from which the moving power, applied to machinery, is obtained, are various, according to the nature of the object, and the amount of force, which is required. Men and animals, water, wind, steam, and gunpowder, are the principal agents, employed as first movers in the arts. Their pow¬ er may be ultimately resolved into those of muscular en- ergy, gravity, heat, and chemical affinity. But, although these are the sources of all the important force, which is artificially employed, in moving large masses of matter, yet, certain other agents are also capable of producing motion, upon a more limited scale ; such as magnetism, electricity, capillary attraction, &c. Vehicles of Power .—Besides the original forces which have been mentioned, there are certain intermediate agents, which serve to accumulate and transmit power, after the first mover has ceased to operate. These agents com¬ monly act, either by their elasticity, their gravity, or their inertia. Springs, and compressed air, are examples of 82 MOVING FORCES USED IN THE ARTS. vehicles, acting by their elasticity, and their usefulness continues, only, till they have recovered the situation from which they were disturbed by another force. In like manner, a weight, acting by its gravity on an axle, or wheel, jDrolongs, for a season, the influence of the power, by which it vvas wound up. Fly-wheels are also vehi¬ cles which serve, by their inertia, to continue the action of a force while it intermits. Vehicles of power are highly useful, in equalizing the irregularities which are in¬ cident to prime movers, in prolonging their action through convenient periods of time, and in multiplying the modes of their application. A fundamental distinction among mechanical agents, both original and secondary, consists in this ; that, in some, the intensity of their action, o-r the acceleration they pro¬ duce in a given time, is the same, whether the body acted upon be at rest, or in motion ; in others, it is greatest, when the body acted on is at rest, and becomes less, as its velocity increases. Gravity is the only force, which is certainly known to act, with equal intensity, on bodies in motion, and at rest; though magnetism, probably, pos¬ sesses the same property. Every other important power acts more forcibly on a body at rest, than on one which has already acquired motion, in the direction in which it acts.* This happens with the strength of animals, the impulse of fluids, and the elasticity of springs. ANIMAL POWER. Muscular energy is exerted through the contraction of the fibres w^hich constitute animal muscles. The bones act as levers, to facilitate and direct the application of this force, the muscles operating on them, through the medi¬ um of tendons, or otherwise. Muscular power is much greater in some animals, than it is in man, owing to their size, or more active mode of life. It is greatest in beasts of prey. Jlfen.—The power of a man to pi’oduce motion, in weights or obstacles, varies, according to the mode in which he applies his force, and the number of muscles * See Playfair's Outlines of Natural Philosophy, vol. i. p. 107. MKN. 83 which are brouglit into action. In the operation of turn¬ ing a crank, a man’s power changes, in every part of the circle which the handle describes. It is greatest, when he pulls the handle upward, from the height of his knees ; next greatest, when he pushes it down, on the opposite side ; though, here, the power cannot exceed the weight of his body, and is, therefore, less than can be exerted, in pulling upward. The weakest points, are at the top and bottom of the circle, where the handle is pushed, or drawn, horizontally. If a windlass be provided with two cranks, placed at right angles with each other, two men will perform much more work, than they could, if the cranks were discon¬ nected ; because, at the moment one puts forth his strength to the least advantage, the other is exerting his with the greatest effect. The mode in which a man can exert the greatest active strength, is in pulling upward from his feet; because the strong muscles of the back, as well as those of the upper and lower extremities, are then brought advantageously into action, and the bones are favorably situated, by the fulcra of the levers being near to the resistance. Hence, the action of rowing is one of the most advantageous modes of muscular exertion 5 and no n)ethod which has been devised for propelling boats, by the labor of men, has hitherto superseded it. According to Mr. Buchanan, the comparative effect produced, by different modes of applying the force of a man, is nearly as follows. In the action of turning a crank, his force may be represented by the number seven¬ teen. In working at a pump, by twenty-nine. In pul¬ ling downward, as in the action of ringing a bell, by thirty- nine. Aiul in pulling upward from the leet, as in rowing, by forty-one.* In estimating the different applications of animal force, we must take into consideration, not only the resistance thev can overcome, but the velocity with which they move, and the length of time, for which they can be con- * See Hrewster’s e IN THE ARTS. Fig. 158. will rise, till the whole water is in a state of steam. It must be observed, however, that the generation of this steam, which is of atmospheric elastic force, affords no available power, but is simply sufficient to balance the column of atmospheric air, and exclude it from a given height of the cylinder. By Condensation .—In the state of things just describ¬ ed, if the steam be suddenly condensed into water, by the application of cold, it is obvious, that the piston will be driven downward, with a force, equal to the weight of the atmosphere which presses on the piston, and through a distance, equal to that which the piston had been raised, by the generation of steam. It follows, that the power of steam, which is of atmospheric elastic force, is, when speedily condensed, directly proportionate to the space which it occupies. If the temperature of this steam be raised above two hundred and twelve degrees, it will oc- GENERATION OF STEAM. 105 copy a larger space, the increase being equal to the ex¬ pansion of steam, by the given change of temperature. But a quantity of heat, nearly equivalent to the increase of volume, will be absorbed ; and hence, says Mr. Tred- gold, the effect of a given quantity of fuel would not be increased by the expedient.* By Generation .—Suppose the same cylinder and ap¬ paratus to have heat applied to its base, with only the difference of the piston being loaded with a given pres¬ sure per inch of its ai’ea. The generation of the steam will raise the loaded piston ; but the height, through which it will be raised, will be less than if it were not loaded. The steam having to act in opposition, both to the pres¬ sure of the atmosphere, and the load on the piston, the space it will occupy will be in the inverse ratio of the pressures which oppose it, supposing the steam of atmos- . pheric elastic force to have been of the same temperature. Thus, if the load on the piston be equal to twice the at¬ mospheric pressure, the piston will be raised only one third of the height; but, on rapid condensation, it de¬ scends with three times the pressure ; and, therefore, whether the steam be generated of atmospheric elastic force, or of a greater force, the power it affords, by gen¬ eration and condensation, is the same, at the same tem¬ perature, and this power is directly as the elastic force of the steam, multiplied by the space it occupies, sup¬ posing that the motion of the piston is rectilinear. But if, as in the last case, a loaded piston be raised, and then a valve be opened, which allows the steam to escape, the whole power gained will be equal only to the weight raised, descending from the height to which it was raised ; and the power, which would have resulted from condensation, will be lost, and the loss is equal to the pressure of the atmosphere, acting through the height, to which the piston was raised by steam. This is the na¬ ture of the common high-pressure steam-engine. It is obvious, that the greater the elastic force of the steam, the less is the proportionate loss, by neglecting to con- ♦ Tredgold, on the Steam Engine, p. 157—159. 106 MOVING FORCES USED IN THE ARTS. dense it under these circumstances ; but it may be re¬ marked, that, unless the valve aperture be equal to the diameter of the cylinder, the steam cannot escape at the necessary rate, without part of the load acting to expel it; and so much more of the effective force will, of course, be lost. The effective power is as the space the steam occupies, multiplied by the excess of elastic force above the atmospheric pressure. Bij Expansion .—Retaining the same loaded piston, let it be raised, by the conversion of a given quantity of water into steam, to the height which corresponds to the load and temperature. Then, if the load on the piston be wholly removed, at that height, the steam will raise the piston, by expanding, till it becomes nearly of the same elastic force as the atmosphere, and its condensation will produce the same effect, as if the steam had been gener¬ ated of atmospheric elastic force, at first. Consequently, the effect, in raising the load on the piston, is wholly ad¬ ditional, and the joint effect of a high-pressure and con¬ densing engine is produced, by the same steam. Hence, by this combination of effect, the power of steam, of high elastic force, will be nearly doubled. This is not, however, the mode by which steam can be applied with the greatest advantage ; for, instead of removing the load on the piston, wholly, at the height to which it was raised, by the generation of the high pres¬ sure steam, a part of it may be removed, and then the steam would expand, to a height depending on the por¬ tion of the load removed ; at that height, remove a second portion, and so on, successively, till the steam becomes of atmospheric elastic force. In this case, as far as the load was raised, in parts, by the expansion of the steam, the efiect is greater than in the preceding combination. This illustrates the principle of the high-pressure expan¬ sion engines of Evans, Woolf, and some others. Again : let the piston be raised, unloaded, as in the first case, by the conversion of a certain quantity of water into steam of atmospheric elastic force. When the piston is at that height, add a weight, equal to half the atmospheric pressure, to the line passing over the pulley. Then the STEAM-ENGINE. 107 elastic force of the steam being unbalanced, the piston would rise, till that elastic force would be half the atmo¬ spheric pressure, or till the piston would be at double its former height. Now, suppose the steam to be condensed, and the weight removed from the pulley, at the same in¬ stant. Then, the power of the descent, after deducting the power added to produce the ascent, will be one half more than it W'ould have been, by simply condensing steam of atmospheric elastic force. This illustrates the prin¬ ciple of the expansion engines of Hornblower and Watt; and it differs from the principle of Woolf, in using steam only of low pressure. The w eight, added to the line pas¬ sing over the pulley, is introduced here, merely to ex¬ emplify the mode of applying a portion of the excess of power, which is accumulated in the fly-wheel, in one part of the operation, to assist the machine, through the rest. It has been assumed, that steam, at least of atmosphe¬ ric elastic force, was generated ; but this is not a necessary condition, for it frequently occurs, that engines work with steam of less elastic force. The same mode of illustra¬ tion will show whence this happens. Let half the pressure of the atmosphere, on the piston, be balanced by a weight over a pulley. Then, on the application of heat, steam of half the atmospheric elastic force would be generated, and raise the piston to double the height that it would be raised, in common cases, by steam, capable of supporting the atmospheric pressure. Consequently, on its being condensed, the descending force will be half the atmos¬ pheric pressure, acting through double the height ; and the steam produces the same effect, as before. The foregoing methods of the application of steam will be found apparent, in the different forms of the steam-en¬ gine, in which they have been called into use. The Steam Engine .—The steam-engine is a machine, bv w'hich the power, derived from steam, is converted to practical use. It has occupied the attention of philoso¬ phers and artists, for more than a century, and is now brought to so great a degree of perfection, as, in the opin¬ ion of many scientific men, to leave little probability of us further improvement. Whether viewed wdth reference 108 MOVING FORCES USED IN THE ARTS. to the great skill which has been employed, in perfecting it, or the importance and extent of its application, it may justly be viewed as the noblest production of the arts, in modern times. For acquiring a clear conception of the steam-engine, as it is now commonly constructed, it will be useful to consider, first, the boiler^ in which the power is generated, and, second, the engine^ in which it is di¬ rected, and applied to use. Boiler .—On account of the gradual rale at which wa¬ ter boils away, it is necessary, in most engines, to keep a large quantity constantly heated, to afford steam with sufficient rapidity for its consumption by the engine. This water is enclosed in a strong, tight, vessel, called the boiler, which is made of iron, or copper, and rests in contact with a furnace. It is requisite, that a boiler should be of sufficient strength, to resist the greatest pressure which is ever liable to occur, from the expansion of the steam. It must also offer a sufficient extent of surface to the fire, to insure the requisite amount of vaporization. In common low-pressure boilers, it requires about eight feet of surface of the boiler to be exposed to the action of the fire and flame, to boil off a cubic foot of water, in an hour ; and a cubic foot of water, thus converted into steam, is equal to a one-horse power.* The strongest form for a boiler, and one of the earliest which was used, is that of a sphere ; but this form is the one which offers least surface to the fire. The figure of a cylinder is, on many accounts, the best; and it is now extensively used, especially for engines of high pressure. It has the advantage of being easily constructed from sheets of metal, and the form is of equal strength, except at the ends. In such a boiler, the ends should be made thicker than the other parts. The furnace is so con¬ structed, that the flame and hot smoke may pass under the whole length of the boiler, and afterwards around both its sides, before escaping to the chimney. In what are cnDed Jiiie-boilers^ a cylindrical furnace is placed within a cylindrical boiler, so that the fuel is sur- See Tredgold, on the Steam Engine, with the following correction, p. 124, lino 2, frotn tbo bottom Tor siBctj/ip road wcti^v. BOILER 109 rounded by water, on all sides, and communicates to it nearly all its heat, except the portion which passes up the chimney. In large engines, which are of low pressure, the form of the boiler, which was used by Mr. Watt, still contin¬ ues to be employed, particularly in England. In this boiler, the upper half is a semi-cylinder, while the lower half is nearly rectangular, with the under side concave, so that a cross section would nearly resemble a horse-shoe. This boiler is less strong than those of a cylindrical form, but it offers a larger surface to the fire, without occupy¬ ing much more space. A boiler of this kind, as it is fit¬ ted up in large engines, with appendages for regulating its 110 MOVING FORCES USED IN THE ARTS, own fire, water, and steam, is represented in the figure, [159,] on the preceding page. A part of the furnace is supposed to be taken away, to bring the boiler into view; and, also, a portion of the boiler is removed, to show its inside. Appendages .—In the figure above referred to, BBBB, is the boiler, made of thick sheets, or plates, of rolled iron, strongly riveted together, a part of which are remov¬ ed, to show the interior. It is supposed to be half full of water, at the boiling temperature. C, is the steam-gauge.^ the object of which is to determine the degree of pressure acting within the boiler. It is a bent iron tube, or invert¬ ed syphon, one end of which communicates with the boil¬ er, and the other end with the atmosphere. The tube is partly filled with mercury, and, as the pressure of the steam increases, the mercury will be driven outward, and will rise in the external leg of the syphon. As the height of the column of mercury cannot be seen, the tube being opaque, a small wooden stem is made to float in the tube, with its end projecting by the side of a graduated scale. Every inch in height, which the stem rises, shows a dif¬ ference of two inches in the two surfaces of the mercury in the tube, and indicates a pressure of about a pound, upon every square inch of the inner surface of the boiler. And, as low-pressure engines are seldom worked with more than three or four pounds to the square inch, the mercury seldom rises higher than three or four inches, in such engines. In high-pressure. engines, the mercurial gauge is not so easily applied ; for these engines are fre¬ quently worked, at a pressure of several atmospheres, and each additional atmosphere requires an addition, of nearly fifteen inches, to the column of mercury. W, is a large opening, called the man-hole, of sufficient size to permit a man to enter the boiler, to clean or exam¬ ine it. It is closed by a strong iron plate. D, is the steam-pipe, which conveys the steam to the engine. It is provided with a throttle-valvm, which is a circular disc, or partition, turning on an axis, and connected with the governor, described on page 77. Its use is to regulate the supply of steam, by closing the pipe, if the engine STEAM-ENGINE APPENDAGES. Ill goes too fast, or by opening it, if it is too slow. FF, are the gauge-cocks^ which indicate the height of water in the boiler. Their extremities stand at difierent depths, in the boiler, one being below the surface of the water, and the other above it. When the water is at the proper height, one of these will emit steam, on being opened, and the other will emit water. They are frequently plac¬ ed on the end, instead of the top, of the boiler. For keeping up a regular supply of water to the boiler, a vertical tube, G, called the feed-pipe, is used. Upon its top, is a small cistern, HHHH, which is kept full of water, by a pump, worked by the engine. At the bottom of this cistern, is a valve, E, connected to one end of the lever, [a6.] At the other end of this lever, is a wire, [dc,] which passes through a steam-tight opening, at [d,] and supports a stone float, [c,] upon the surface of the water, the stone being counterbalanced by a weight, at the valve, [c.] When the water lowers, in the boile’" flie stone float descends, and, by acting upon the lever, opens the valve, [e.] Water immediately flows in, from the cistern, and continues to do so, till the float rises, and shuts the valve. It will be observed, that the column of w^ater, in the feed-pipe, must be sufficiently high to counterbalance the pressure of steam, in the boiler. On this account, it can not be applied in high-pressure engines, without making it of a very inconvenient height. In these en¬ gines, therefore, w'ater is supplied to the boiler, by a small forcing pump, worked by one of the reciprocating parts of the engine ; and it is frequently heated, before being pumped in, that it may not check the production of steam. For the purpose of regulating the fire, the feed-pipe is furnished with an iron bucket, O, hung by a chain, w'hich passes over two pullies, PP, and is attached by its other extremity to an iron damper. A, which commands the chimney. When the steam in the boiler is urged to too great an extent, it forces the water upward, in the feed-pipe, and causes the iron bucket to ascend. This lowers the damper into the smoke-flue, and, by thus intercepting the current of air, checks the force of the 112 MOVING FORCES USED IN THE ARTS. fire. In some boilers, the passage, which brings air to the fire, is intercepted, instead of the smoke-flue. ^ — To prevent the boiler from bursting, if, by accident, the pressure of the steam should become too great lor the strength of the boiler, a safety-valve is provided, at S, opening outward. It is kept down by a weight, so that it cannot be raised, except by a greater force than that W'hich is required to work the engine. It is highly im¬ portant, however, that it should not be liable to any other weight, or encumbrance, than that which the engine re¬ quires ; and, to prevent this danger, it is enclosed in a case, which is kept locked. When the engine stops working, or the steam is generated too rapidly for its ex¬ penditure, the safety-valve rises, and the superfluous steam rushes out, with a hissing noise. Another safety-valve is also provided, which differs from the preceding, in opening inivards. It is kept up by a counter weight, on a lever, and its use is to prevent the weight of the atmosphere from crushing in the sides of the boiler, when the engine stops working, and the steam cools. As boilers are usually proved, before being submitted to use, the accident of bursting does not happen, from a general want of strength, unless the safety-valve be over¬ loaded. It is most likely to happen, either from neglect, in suffering the water to get too low, in some part of the boiler, so that the metal is excessively heated, or else, from the corrosion of the metal, in places, by oxidation, after long exposure to the fire. If a sediment is suffered to accumulate, to a considerable depth, on the bottom of the boiler, it has the effect to exclude the water from con¬ tact with the metal, so that the metal becomes hotter, and is more rapidly oxidated, and even softened, by the heat. The violent explosions which have sometimes occur¬ red, projecting the contents and fragments of the boiler to a great distance, have been rationally accounted for, by supposing that certain parts of the metal, through neg¬ lect, become heated to a high temperature, and, that por¬ tions of water, being suddenly brought into contiguity with them, produce steam, of which the initial elastic force is STEAM-ENGINE APPENDAGES. 113 extremely great. In this case, the boiler may burst, be¬ fore the inertia of the water or safety-valves, is over¬ come ; and the stronger is the boiler, the greater may be the explosion. As a great number of lives have been lost by the ex¬ plosion of boilers, particularly on board of steam-boats, much attention has been bestowed on the means of pre¬ venting such accidents. The principal attempts have consisted, in a more accurate regulation of the safety- valves, and in the introduction of plugs of fusible metal, W'hich melt, when the temperature is raised a little above llie boiling point of water, and thus suffer the steam to escape. But absolute security has only been found, in placing the boiler in such a situation, that, if it should burst, it would occasion no injury to the passengers in the boat. This is effected, by placing the engine in a boat by itself, or by interposing a strong barrier between the boilers, and the persons on board the boat. Mr. Treadwell has proposed to use the steam, at a pressure not greater than that of the atmosphere, and to compen¬ sate the loss of force, by an increase in the size of the cylinder and piston. Besides the forms of the boiler, already mentioned, various others have been employed, such as combinations of tubes, and other figures, intended to multiply surface, for the purpose of raising more steam, from the same amount of water, in a given lime. They have been applied in some high-pressure engines, but, in most ca¬ ses, the simpler forms are preferred.* Jn Brathwaite and Ericsson’s engine, which has been applied, with partic¬ ular success, to propelling carriages on rail-roads, the hot air of the furnace is forcibly drawn, in a circuitous flue, through the boiler, by means of a revolving, fan-like ap¬ paratus ; thus communicating to the boiler a greater quan¬ tity of heat, in a given time, than could be obtained from the common atmospheric draught. * In Perkins’s engine, a strong vessel, called a generator, is kept full of water heated to a high temperature. Portions of the water are suc- ccssiveljt forced out ; and reliance is placed on the heat already in this water, to produce from it the requisite amount of steam. 10 * 114 MOVING FORCES USED IN THE ARTS. Engine .—The steam being generated in sufficient quantities in the boiler, it is next applied to use in the working, or moving, part, which we have called the en¬ gine. Of this engine, a great variety of forms and mod¬ ifications have been proposed, and adopted, at different times. A few of those, which are effectual in their prin¬ ciple, and most extensively employed, will now be con¬ sidered. J^on-condensing Engine .—The simplest form of the steam-engine is that of the non-condensing, commonly called the high-pressure, engine. In this engine, the ap¬ paratus for condensation is dispensed with, and the steam is worked at a high temperature, and afterwards discharg¬ ed into the open air. Of course, a part of the force of the steam is expended, in overcoming the pressure of the atmosphere, and the surplus, only, can be applied to drive machinery. That this surplus may be sufficient to pro¬ duce the requisite power, a pressure of thirty or forty pounds, on a circular inch, above the atmospheric pres¬ sure, is commonly kept up in these engines.* The manner, in which the engine is made to operate, is, briefly, as follows. The steam, in escaping from the boiler to the open air, is obliged to pass through the cyl¬ inder, the cavity of which is closed, except where it com¬ municates with the valves. By the opening and shut¬ ting of these valves, the steam is made to enter the cylin¬ der, alternately, at each end, and escape by the opposite end. But, in doing this, its passage is always intercepted by the piston ; so that, before it can escape, it must move the piston from one end to the other of the cylinder. The repetition of this movement gives motion to a beam, or other alternating part, from which it is communicated, by a connecting rod and crank, to a fly-wheel, in the same manner as is seen in the condensing engine, [PI. III.] hereafter to be described. The figure, there i*epresented, may be considered as a non-condensing engine, if we re¬ move from it the condenser, and its appendages, occupy¬ ing the lower part of the plate. B, represents the boiler; C, the pipe, which conveys the steam ; D, the cylinder ; See Tredgold, on the Steam Engine, p. 181. CONDENSING ENGINES. 115 E, the piston ; F, the beam ; [A,] the crank ; G, the fly-wheel. The different apparatus of valves, by which the entrance and escape of steam is regulated ; also, the other appen¬ dages of the engine, will be considered in another place. In arranging the time of their opening and shutting, it is usual to allow not quite all the steam to escape, at the end of the stroke. A small portion is retained, to receive the shock of the piston, and, by its elasticity, to destroy its momentum, and cause it to recoil back, without loss of force. Non-condensing engines sometimes work by the gener¬ ative force of steam, and, sometimes, by the generative and expansive force. They are used in cases where simplic¬ ity and lightness are required, as in locomotive engines ; also, in situations where a sufficient supply of water, for condensation, cannot easily be obtained. They are infe¬ rior, in safety, to condensing engines ; yet, as they cost much less at the outset, for the expense of building, they are often preferred for small, or temporary, works. In proportion to the high temperature at which the steam is worked, great caution is necessary, in regard to the strength and management of the boiler, in these engines. Condensing Engines .—Engines of this class are fitted up, with an apparatus for condensing the steam into water, so that a vacuum, nearly complete, is formed in one part of the cylinder, just before the stroke of the piston, into that part, takes place. By this construction, the resist¬ ance of the atmosphere is avoided ; and, thus, the power of the engine, to perform work, is much increased. The steam, also, is sufficiently powerful for use, at compara¬ tively low temperatures ; and hence arises the increase of safety which is found in low-pressure engines, a name giv¬ en to those condensing engines, which are worked with steam of moderate elastic force. In the atmospheric engine, invented by Newcomen, the piston was raised by the steam, aided by a counter weight, till it arrived at the top of the cylinder, which was left perfectly open. A jet of water was then admitted into the bottom of the cylinder, which suddenly condensed 116 MOVING FORCES USED IN THE ARTS. the steam, so that, a vacuum being formed, the piston was driven down, by a force equal to the weight of the column of superincumbent air. The water was now excluded by a stop-cock, and the steam readmitted. The piston was thus again raised, and the process repeated as before. A great inconvenience attended this method, arising from the circumstance, that the cylinder itself required to be heated and cooled, at each stroke of the piston, thus oc¬ casioning great delay, and an unnecessary expense, both of fuel, and of cold water. To remedy this evil, Mr. Watt invented the separate condenser, which is a strong vessel, situated at a distance from the cylinder, but com¬ municating with it by a pipe, so as to form with it a com¬ mon cavity, without reducing, materially, its temperature. Into this vessel, the jet of cold water is thrown, and, as all the communicating pipes are governed by valves, or cocks, the cylinder, below the piston, is alternately filled with steam, from the boiler, and emptied of steam, by the condenser. In the double-acting engine, invented by Mr. Watt, the top of the cylinder was closed, and rendered air-tight, the rod of the piston, only, passing through it. Thus, the cylinder is divided, by the piston, into two cavities, both communicating with the boiler, and both with the condenser. By the aid of valves, an alternate communi¬ cation is kept up, so that the steam, being alternately ad¬ mitted at both ends, impels the piston, successively, in both directions, while the condenser, at the same time, destroys the resistance. In this engine, compared with the single engine of Mr. Watt, which was previously in use, a double quantity of steam is used, and a double power exerted, in the same space and time. • Description .—In PI. III., is a view of a double-actin| steam-engine, nearly as constructed by Murray, and upon the same general principles as those of Mr. Watt, vary- ing, however, in the valves, and some other particulars. A, represents the furnace, which is here shown in sec¬ tion, as is also the boiler, above it, and all the principal cavities of the engine. The flame and hot smoke, after passing underneath the boiler, for its whole length, return DOUBLE-ACTING STEAM-ENGINE. 117 through the side passages, [c/J,] before they are dischar¬ ged into the chimney. B, is the boiler, which, in this example, is of a cylin¬ drical form, a shape better adapted for strength, than that represented in Fig. 159. The appendages represented in Fig. 159 are not here repeated. Some of them, indeed, are not used in steam-boats, and in small engines. The boiler is commonly made of sheets of iron, strongly rivet¬ ed together, and tightened by hammering. If intended to contain salt water, the boiler is made of copper, to prevent corrosion. CCC, is the steam-pipe, which carries the steam from the boiler to the cylinder, through the valve, I. It is made of cast-iron, and its joints screwed together by flanges. T>, is the cylinder, communicating, by passages at the top and bottom, with the valve, !.• The cylinder is made of cast-iron, and accurately bored, to make its inner sur¬ face smooth and true. E, is the piston, which, by its rod, [e,] gives an alter¬ nating motion to the beam, [//,] about its centre, F, the other end of which, by another connecting rod, [^,] gives motion to the heavy fly-wheel, GG, by means of a crank, [/i.] Thus, after the engine has begun to work, its power is accumulated in the fly-wheel, and a circular motion may be communicated from it to any machinery. H, is an eccentric circle, on the axle of the fly-wheel, G. It gives motion through the medium of its levers, and j/c,] and the connecting rods, [H/cxj/, andzl,] in a manner easily understood, by inspection, to the valve, I. I, is a cofFer-valve, capable of sliding up and down, and having a cavity on the side next the cylinder. By moving up and down, it opens and shuts the passages, and admits the steam, alternately, to each end of the cylinder ; and, at the same time, forms a communication between the opposite end, and the condenser. W, is the governor, which regulates the speed of the engine. It resembles the governor described in chap. XV. but has its movable collar on tbg top, at [s.] It may be turned by a band, from the axle of the fly-wheel, or placed directly over the axle, and geared to it by bevel-wheels. 118 MOVING FORCES USED IN THE ARTS. When the fly-wheel moves too fast, the balls of the gov¬ ernor recede from their centre, and, by acting on a lever, [rs,] cause it to turn upon its fulcrum, [f,] and partially to close the steam-pipe, by a throttle-valve, at K. When the velocity abates, the balls subside, and the valve opens, so as to admit more steam. L, is the air-pump, the use of which is, to discharge the air and water, which collect in the condenser, M. M, is the condenser, which is an empty, cylindrical vessel, immersed in a cistern of cold water, SS, and communicating with the cylinder by the pipe, O. It has a valve, or cock, communicating with the cistern, and moved by the rod, [^^,] through which a jet of cold water enters it, for the purpose of condensing the steam. N, is a small cistern, filled with water. Into this cis¬ tern enters a pipe, from the condenser M, the top of which pipe is covered by a valve, which is called the blow-valve, or, sometimes, the snifting-valve. Through this valve, the air, contained in the cylinder, D, and passages from it, is discharged, on the engine being first set in motion. O, is the eduction-pipe, which conducts the steam from the valve, I, to the condenser, M. P, is the pump, which supplies with w'ater the cistern, or cold well, SS, in which the condenser and discharging pump stand. QQ, are iron columns, which support the beam. Of these, the engine has four, although only two are shown. They stand upon one entire plate, seen edgewise, on which the principal parts of the engine are fixed. RR, is the recess below the floor, for containing the cistern of the discharging pump, condenser, &c. The condenser, M, and the air pump, L, communicate by means of a horizontal pipe, containing a valve, [«i,] opening towards the pump ; the piston [n,] of this pump, also contains two valves, and the cistern, T, at the top of the pump-cylinder, contains other two valves, which, like those of the piston, [n,] open upwards. When the piston, E, of the cylinder, is depressed, the piston [n,] of the discharging pump, it will be obvious to inspection, EXPANSION ENGINES. 119 will be depressed, likewise, and its valves open, while the valve, [w,] closes ; hence, the water of the condensed steam, as well as the injection water, and any vapor of air, which may be present, having passed through the valve, [m,] passes through the piston, [n ;] and, when that piston is drawn up, its valves close, and prevent their return, as in common pump-work. The water and air, that have thus got above the piston, as the latter rises, open the valves at the bottom of the cistern, T, in which the water remains till it is full; but the air passes into the atmosphere. As the water in the cistern, T, is in a hot state, a part of it, for the purpose of economizing fuel, is pumped up, and returned to the boiler, the pump-rod being attached to the great beam. The steam, constantly rushing into the condenser, M, has a perpetual tendency to heat that vessel, as well as the water of the cistern, SS, in which it stands ; the whole of the steam, if this were unchecked, would not be condensed, or the condensation would not be sufficiently rapid, because the injection water itself flows out of this cistern. A part of the w'ater is, therefore, allowed to flow from this cistern by a waste pipe, and an equal quan¬ tity of cold water is constantly sujiplied by the pump, P. The cylinder, D, is, in many cases, surrounded by a case, to keep it from being cooled too much, by contact with the external atmosphere. Expansion Engines .—The steam, which impels an engine is always diminished in volume, by the resistance which it has to overcome, and tends, naturally, to occupy a larger space, than that to which it is confined, while the engine is at work. If it be dismissed into the air, or into the condenser, while under its greatest working pressure, it w’ill not have produced all the useful effect, which it is capable of aflbrding. If, on the contrary, it be separa¬ ted, and placed under circumstances, where it can still expand further, before it is dismissed, this expansion will be so much additional gain to the power of the engine. Its general principles have already been discussed. The expansive power of steam may be converted to use, in various ways, and most of the common forms of 120 MOVING FORCES USED IN THE ARTS. the steam-engine may be made to act expansively, by a proper arrangement of their valves. In Watt’s engine, this effect is produced, by cutting off the steam from the cylinder, before the stroke of the piston is completed, leaving it to the steam, already in the cylinder, to assist, by its expansion, in completing the stroke. The steam in the boiler, being thus intercepted, acts only at intervals. Nevertheless, its whole disposable force is accumulated in the fly-wheel, while, at the same time, the force, arising from the expansion of steam in the cylinder, serves to in¬ crease the total amount. A great augmentation is thus produced, in the useful effect of an engine, with the same amount of fuel and water. Mr. Hornblower, who was one of the first inventors of the application of expansive steam, employed two cylinders, having their pistons connected to the same beam. In the smaller of these, the steam was used, at full pressure, after which it was discharged into the lar¬ ger cylinder, where it again acted, by its expansive force. This method affords a more equable mode of applying the expansive force of steam, than that used by Mr. Watt; but the engine is more complex and expensive. Mr. Woolf afterwards adopted the plan of two cylin¬ ders, with the addition of using his steam at a high pres¬ sure, together with a condenser. He appears to have exaggerated the expansive force of steam, at high tem¬ peratures, as various other projectors have done. His engines, however, continue to be used and approved, in different parts of England and Wales, and their perfor¬ mance is stated to exceed that of any other kinds. Condenser .—It has already been stated, that, in the original atmospheric engine of Newcomen, the steam was condensed by a jet of cold water, thrown into the cylin¬ der. A great improvement, in the economy of heat, was made by Mr. Watt, who introduced the separate con¬ denser. But, even with this improvement, there is some loss of power, in consequence of the necessity of con¬ tinually pumping out the water, which has been injected, to condense the steam. Sea-water, also, gives trouble, by the deposit of salt in the boiler. To obviate these VALVES. 121 difficulties, condensers have been made, of a multitude of small tubes, communicating with the eduction-pipe, and kept immersed in cold water. In this W'ay, sufficient heat escapes, through the surface of the tubes, to condense the steam, without the necessity of injection ; and the water is kept fresh. Some of the Atlantic steam-boats iiave had condensers of this kind. A difficulty, however, is found, in the expansion and contraction of the tubes, which makes it necessary to receive the ends of all of them in stuffing boxes, which admit motion, but are li¬ able to get out of order. In a large engine, now work¬ ing at tlie Iron-works, in Boston, Mr. Treadwell has in¬ troduced a condenser, the tubes of which are bows, having both ends soldered to the same surface, and, therefore, not liable to be displaced, by expansion, or contraction. Valvts .—The valves of steam-engines are shutters, which guard the avenues to the boiler and condenser, so that, by opening and shutting them, at the required time, the steam may be made to enter, or escape, at either end of the cylinder. Valves, of a great variety of forms, have been used in different engines, some of which have a reciprocating, others, a rotary, motion. The puppet valve is a cone, or frustum of a cone, which is fitted, like a cover, to a conical aperture, which it opens, by rising, and closes, by falling. Sliding valves are those which do not rise, but slide on and off of their apertures. Some of these have a cavity, on their under side, capable of connecting two apertures together, or of forming a com¬ munication between them, while a third aperture is shut. Rotary valves are usually constructed like common stop¬ cocks, excepting that they command more passages than one, at the same time. If the handle be placed in one position, it opens one passage, while it closes another ; if in a different position, it closes the first, and opens the second. A throttle valve is a partition, turning on an axis, and placed across the interior of a pipe. If turned edgewise, it permits the steam to pass ; but, if turned transv’^ersely, it obstructs its passage. This valve is com¬ monly placed in the main steam-pipe, and connected with It. 11 XII. 122 MOVING FORCES USED IN THE ARTS. the governor, to regulate the quantity of steam supplied by the boiler. On account of the heat ivhich is kept up in steam-en¬ gines, the principal valves require to be of metal, and are fitted, by grinding, closely to their seats. Valves made with leather, like the common clack valve of a pump, can only be used about the condenser, where the temper¬ ature is low. Pistons .—As the piston is liable to continual wear, by its friction against the inside of the cylinder, it can only be kept sufficiently tight, by rendering its circumference elastic. This is commonly done, by winding it with hemp, loosely twisted. The hemp packing, however, gets out of order, in time, and requires to be renewed. To remedy this evil, various plans have been introduced, for making elastic pistons of metal only. The pistons invented by Cartwright and Barton, consist of several parallel circular plates, in close contact with each other. These are cut into segments, and the segments pressed outward, by steel springs, care being taken, that the fis¬ sures, in the difterent plates, do not coincide. In the pis¬ ton of Jessop, a spiral coil of steel is wound on the cir¬ cumference of the piston, which expands, by its own elas¬ ticity, so as to keep in tight contact with the cylinder. To increase the tightness and elasticity of the piston, a hempen packing is placed wdthin the coil. Parallel Motion .—A simple form of a parallel mo¬ tion, for converting the rectilinear motion of the piston into the curvilinear one of the beam, has already been described, on page 66. Another form is shown in Plate III., where the rod, [ab,'] turns upon the joint, [a,] as a fixed centre, while the rod, [c6,] turns u])on [i,] as a cen¬ tre. While the point, [c,] would describe a curve about its centre, [6,] the point, [Z>,] describes an opposite curve about its centre, [a.] These two curvatures compensate each other, so that the point, [c,] to w’hich the piston is attached, describes nearly a straight line. The parallel motion was introduced by Mr. Watt, and is, probably, attended with less friction than any other ar¬ rangement, for effecting the same object. It requires. o INTERNAL CONSTRUCTION OF A LOCOMOTIVE ENGINE.—[To /oc« page 123.1 LOCOMOTIVE ENGINE. 123 however, to be constrLicted with great accuracy. Va¬ rious other methods have been applied, to convert the rectilinear into a curvilinear movement. Sometimes, the piston is confined to its path by guides, or friction wheels, and connected to the beam by a double joint. In New¬ comen’s engine, where the principal force was in the downward stroke, the piston was connected, by a chain, to an arched head, at the end of the beam. In Cart¬ wright’s engine, the piston was attached to two opposite cranks, which were geared together, as shown on page 66. In some of Murray’s engines, the epicycloidal movement was employed. [See page 69.]* In Maud- slay’s engine, and some others, instead of a beam, a cross-head is used, the whole of which moves up and down, in guides, instead of turning on a centre. In the vibrating engines of Lester, and others, the cylinder is hung upon a movable axis ; and, in Morey’s engine, the cylinder revolves, like a fly-wheel, the piston being made to act on a fixed crank. Locomotive Engine .—This engine is used, as a propel¬ ling power, on rail-ways, and has been introduced in a previous chapter. The accompanying figure shows the internal construction of one of these machines. F, represents the fire-box, or place where the fire is kept ; I), the door, through which the fuel is introduced ; G, one of the bars of the grate, at the bottom ; the spa¬ ces, marked B, are the interior of the boiler, in which the water stands, at the height indicated by the dotted line The boiler is closed on all sides; all its openings being guarded by valves. The tubes, marked [ce,] conduct the smoke and flame of the fuel, through the boiler, to the chimney, CC, serving, at the same lime, to communi¬ cate the heat to the remotest part of the boiler. By this arrangement, none of the heat is lost; as these tubes are all surrounded by the water. SSS, is the steam-pipe, open at the top, BS, having a steam-tight cock, or reg¬ ulator, V, which is opened and shut by the crank, H, * For an account and figure of an engine, of this kind, see Farey on the Steam Engine, p. 086, and Plate XV'II. J24 MOVING FORCES USED IN THE ARTS. extending outside of the boiler, and which is managed the engineer. The operation of the machine is as follows : The steam being generated in great abundance, in the boiler, and being unable to escape out of it, acquires a considerable degree of elastic force. If, at that moment, the cock, V, is opened, by the handle, H, the steam, penetrating into the tube, S, at the top, near X, and in the direction ol the arrows, passes through the tube, and the valve, V, and enters the valve-box, [i.] There, a sliding valve, [oo,] which moves at the same time with the machine, opens for the steam a communication, successively, with each end of the cylinder. Thus, in the figure, the en¬ trance, on the left hand of the sliding valve, is represented as being open, and the steam follows, in the direction of the dotted line, into the cylinder, where its expansive force will move the piston, P, in the direction of the ar¬ row. The steam, or air, on the other side of the piston, passes out, in the direction of the dotted line, to [m,] which communicates with the tube, [^^,] from which it passes into the chimney, C, and thence into the open air. The sliding v^alve, [oo,] now moves, and leaves the right-hand aperture open, while it closes the one on the left. The steam then draws the piston back; and that portion of steam, on the left of the piston, having performed its of¬ fice, passes out of the aperture, [it,] an opening to which is made, by the new position of the sliding valve. Thus, the sliding valve, opening a communication, alternately, with each side of the piston, the steam is admitted on both sides of the piston, and, having performed its office, it passes through the aperture, [m,] to the tube, [f/,] and the chimney, C, and from thence into the open air. Motion being thus given to the piston, it is communi¬ cated, by means of the rod, R, and the beam, G, to the crank, K ; which, being connected with the axle of the wheel, causes it to turn, and thus moves the machine. _ Power of the Steam Engine. —Dr. Gardner has given the following statements, relating to the power of the steam-engine. In a report, published in 1835, it was announced, that POWER OF THE STEAM-ENGINE. 125 a steam-engine, erected at a copper-mine, near St. Aus tie, in Cornwall, had raised, by its average work, ninety- five millions of pounds, one foot high, with a bushel of coals. This enormous mechanical effect having given rise to some doubts, as to the correctness of the experi¬ ments, on which the report was founded, it was agreed, that another trial should be made, in the presence of a number of competent, and disinterested, witnesses. This trial, accordingly, took place, and was witnessed by a number of the most experienced mining engineers, and agents. The result was, that, for every bushel of coals, consumed under the boiler, the engine raised one hun¬ dred and twenty-five and a half millions of pounds weight, one foot high. It may not bo uninteresting to illustrate the amount of mechanical virtue, which is thus proved to reside in coals, in a more familiar manner. Since a bushel, of coal weighs eighty-four pounds, and can lift fifty-six thousand and twenty-seven tons, a foot high, it follows, that a pound of coal would raise six hun¬ dred and sixty-seven tons, the same height; and, that ah ounce of coal would raise forty-two tons, one foot high, or it would raise eighteen pounds, a mile high. Since a force of eighteen pounds is capable of drawing two tons, upon a rail-way, it follows, that an ounce of coal possesses mechanical virtue sufficient to draw two tons, a mile, or one ton, two miles, upon a level rail-way. The circumference of the earth measures twenty-five thousand miles. If it were begirt by an iron rail-w^ay, a load of one ton would be drawn round it, in six weeks, by the amount of mechanical power which resides in the third part of a ton of coals. The great pyramid of I'gypt stands upon a base, meas¬ uring seven hundred feet, each way, and is five hundred feet high ; its weight being 12,760,000,000 pounds. To construct it, cost the labor of one hundred thousand men, for twenty years. Its materials would be raised from the ground, to their present position, by the combustion of four hundred and seventy-nine tons of coals. The weight of metal, in the Menai bridge, is four mil- 1 1 *^ 126 MOVING FORCES USED IN THE ARTS. lion pounds, and its height, above the level of the water, is one hundred and twenty feet. Its mass might be lifted from the level of the water, to its present position, by the combustion of four bushels of coals. Projected Improvements. —Besides the improvements which have been actually effected, in the construction and application of the steam-engine, a variety of projects, for increasing the power and usefulness of this agent, have, from time to time, occupied the attention of ingen¬ ious men. Of the improvements which have been at¬ tempted, some are opposed by obstacles, which have not yet been satisfactorily surmounted, and others, by difficul¬ ties, in themselves, insurmountable. The following have been among the most prominent subjects of speculation. 1. Rotative Engines. —These are engines, in which the steam is so applied, as to produce a direct rotary mo¬ tion, without the intervention of a rectilinear movement. Engines, on this principle, have been constructed in many different ways. An idea of one of the most obvious forms, may be obtained from the eccentric pumps, de¬ scribed in the following chapter, which have been con¬ verted into steam-engines, by reversing the motions, and changing the resistance for the power. Some rotative engines have been constructed on the principle of Bar¬ ker’s mill ; others have been made, by immersing an overshot-wheel in a cistern of heated fluid, either water, oil, or melted metal, and delivering the steam under the ascending or inverted buckets ; so that, when these were filled with steam, the full buckets, on the opposite side, might preponderate, and cause the wheel to revolve. But, in general, the rotary engines hitherto constructed, have either been feeble in power, or encumbered with excessive friction, on account of the extensive packing, which is necessary, to keep them tight; so that none of them have found their way into use. It is probable, that no method of constructing a variable cavity, for steam, which is, in other respects, suitable, affords so advantage¬ ous a mode of applying the power, as the cylinder and piston, producing rectilinear motion. Use of Steam at high Temperatures. —In non-conden- USE OF VAPORS OF LOW TEMPERATURE. 127 sing,, or high-pressure engines, the power, which is conver¬ tible to use, consists of the surplus which remains, after overcoming the pressure of the atmosphere. Of course, the higher is the temperature at which the steam is worked, the greater is the total gain, supposing the absorption of heat, and the production of power, to continue to take place, in equal proportions. This consideration, with other expected advantages, has given rise to many attempts to improve the steam-engine, by devising modes of applying steam, at much higher temperatures than those, which it has been ordinarily found practicable to employ. At¬ tempts of this kind have, also, frequently been founded upon an undue estimate of the elastic force of steam, at high temperatures, and of the absorption of heat, during its production. In practice, it is found difficult to obtain a material, capable of conQning water and steam, in safety, when raised to such a temperature, as to produce a pres¬ sure of ten, or more, atmospheres ; since, independently of the strain uj)on the joinings, the cohesive strength of metals is diminished, and their oxidation promoted, by exposure to great heat. Use of Vapors of low Temperature .—Certain liquids, such as alcohol, ether, sulphuret of carbon, and a liquid, obtained .by condensing oil-gas, have been proposed, as substitutes for water, in producing steam, on account of the low temj)erature, at which they are converted into vapor. Thus, alcohol boils at about one hundred and seventy-three degrees of Fahrenheit; sulphuric ether, at ninety-eight degrees ; muriatic ether, at fifty-one degrees ;* sulphuret of carbon, at one hundred and sixteen degrees ; and oil-gas liquid, at one hundred and eighty-six ; all of which are lower than the boiling point of water. Some of these, when raised to the boiling point of water, have a much greater elastic force than that fluid. Thus, the sul¬ phuret of carbon, at two hundred and twelve degrees, has an elastic force equal to about four atmospheres,! and sul¬ phuric ether, of nearly six atmospheres. But these advan- * lire’s Dictionary. t See Tredgold’s Tables, Steam Kiigine, p. 78—81. 128 MOVING FORCES USED IN THE ARTS. tages are nearly counterbalanced, by the small spaces through which these vapors act, their volume, at their boiling point, being only from about an eighth to a third part of that of steam, at the boiling point of water. To this disadvantage may be added the expensive character of these substances, and the difficulty of condensing them, without loss, in any working engine. Some of them, like¬ wise, as the ethers, act, chemically, upon metals, and could not, on this account, be employed in engines made of the common materials. Gas Engines .—It has been attempted to obtain power for propelling machinery, from the combustion, or explo¬ sion, of inflammable elastic fluids, such as coal-gas, and the vapor of combustible liquids, mixed with atmospheric air. In combustions of this kind, rarefaction, and sub¬ sequent condensation, take place, which, if conducted within suitable cavities, may be made to afford a moving power, applicable to machinery. The principal engines, which have been constructed, for using this power, are those of Messrs. Morey, in this country, and Brown, in England. If a power of this kind could be made, to af¬ ford an adequate propelling force for locomotive engines, upon public roads, it would possess an advantage, in the lightness of the machinery, compared with the weight of steam-engines, with their water and fuel. But it remains for experience to determine, whether the space, through which the force will act, taken in connexion with the cost of the materials, can render this an economical source of power. In addition to the foregoing method of procuring power, by the combustion of gases, Sir H. Davy has proposed the employment of certain fluids, which are volatile at common temperatures, but which have been condensed into liquids, under great pressure, such as carbonic acid, ammonia, &c. His views are founded upon the immense difference which exists, between the increase of elastic force in gases, under high, and low, temperatures, by simi¬ lar increments of temperature. But doubts have been raised upon this subject, with regard to the space, through which the force of these gases will act, and, also, in regard STEAM-CARRIAGES.-STEAM-GUN. 129 to the quantity of heat, requisite to produce the change of temperature required.* . Steam Carriages .—It has long been a favorite object with projectors, to construct a form of the steam-eqgine, in connexion with a carriage, which should be capable of propelling itself upon the public roads. Locomotive en¬ gines are capable of moving themselves upon rail-roads, and of drawing with them additional loaded carriages; be¬ cause, in this case, the motion is uniform, and very little of the power is expended, in surmounting obstacles, or changing the form of the road. But, upon a public high¬ way, it requires, by a common estimate, about eight times as much power to propel a carriage, as it does upon a rail-road. Of course, the weight and inertia of an engine, capable of producing this power, must increase somewhat in the same proportion, and a great part of the power will become necessary, to transport the machine itself. The inertia, also, will be continually brought into unfavorable action, by the jolts and concussions, inseparable from high¬ way travelling, and thus endanger the destruction of a ma¬ chine, requiring such nice adaptation of parts, as the steam- engine. It appears, that steam-carriages have been made to run upon goodtfoads, during short experiments, while the engine was new. But we have no account, as yet, of any one having long performed this kind of service. Steam Gun. —^Ir. .1. Perkins,f whose experiments on the steam-engine are well known, has attempted the em¬ ployment of the expansive force of steam, as a substitute for gunpowder, in throwing projectiles. The steam-gun, invented by him, is somewhat similar, in its construction, to the air-gun ; but the power is derived from a magazine of water, heated to a very high temperature ; so that, when portions of it are discharged from the vessel containing it, they produce steam enough to project a cannon ball with great force. The balls are admitted into the gun, in succession, from a hopper, and can be discharged, at • Philosophical Transactions, 1826, Tredgold, on the Steam Engine, p. 84 . t The public are indebted to Mr. Perkins, for the art of steel engrav¬ ing, the nail machine, and many other useful mventions. 130 MOVING FORCES USED IN THE ARTS. the rate of twenty-four in a minute. It appears, from some experiments made with these guns, in France, that the projectile force of steam is greatly inferior to that of gunpowder; a consequence, no doubt, of the vast differ¬ ence, which is known to exist, in the initial force of the two agents ; nevertheless, the rapidity, with which the dis¬ charges may be made, seems capable of advantageous employment, in some situations. GUNPOWDER. Manufacture .—Gunpowder is a solid, explosive, mix¬ ture, composed of nitre, sulphur, and charcoal, reduced to powder, and mixed intimately with each other. The proportion of the ingredients varies, very considerably ; but good gunpowder may be composed of the following proportions ; seventy-six parts of nitre, fifteen of char¬ coal, and nine of sulphur, equal to one hundred. These ingredients are first reduced to a fine powder, separate¬ ly, then mixed, intimately, and formed into a thick paste. This is done, by pounding them, for a long time, in wood¬ en mortars, at the same time moistening them with water, to prevent the danger of explosion. The more intimate is the mixture, the better is the powdei^; for, since nitre does not detonate, except when in contact with inflamma ble matter, the whole detonation will be more speedy, the more numerous the surfaces in contact. After the paste has dried a little, it is placed upon a kind of sieve, full of small holes, through which it is forced. By that jirocess, it is divided into grains, the size of which depends upon the size of the holes, through which they have passed. The powder, when dry, is put into barrels, which are made to turn round on their axis. By this motion, the grains of gunpowder rub against each other, their asperi¬ ties are worn off, and their surfaces are made smooth. The powder is then said to be glazed. The granulation and glazing of the powder causes it to explode more quickly, perhaps, by facilitating the passage of the flame among the particles. Detonation .—When gunpowder comes in contact with any ignited substance, it explodes, as is well known, with FORCE. 131 great violence. This effect may lake place, even in a vacuum. A vast quantity of gas, or elastic fluid, is emit¬ ted, the sudden production of which, at a high tempera¬ ture, is the cause of the violent effects which this sub¬ stance produces. The combustion is, evidently, owing to the decomposition of the nitre, by the charcoal and sulphur. The products are, carbonic oxide, carbonic acid, nitro¬ gen, sulphurous acid, and, probably, sulphureted hydro¬ gen. Mr. Cruikshanks has ascertained, that no pertep- tible quantity of water is formed. What remains, after the combustion, is potash, combined with a small portion of carbonic acid, sulphate of potash, a very small propor¬ tion of sulphuret of potash, and unconsumed charcoal. Force .—The elastic fluid which is generated, when gunpowder is fired, being very dense, and much heated, begins to expand, with a force, at least, one thousand times greater than that of air, under the ordinary pressure of the atmosphere. And, allowing the pressure of the at¬ mosphere to be fourteen and three fourths pounds, upon every square inch, the initial force, or pressure, of fired gunpowder, will be equal to, at least, fourteen thousand seven hundred and fifty pounds, upon every square inch of the surface which confines it. But this estimate, which is that of Mr. Robins, is one of the smallest which has been made. According to Bernoulli, the initial elasticity, with which a cannon ball is impelled, is, at least, equal to ten thousand limes the pressure of the atmosphere; and, from Count Rumford’s experiments, it appears more than three times greater than this. (? unpowder, on account of its expensiveness, and the suddenness and violence of its action, is not employed as a regular moving force, for machinery. It is chiefly ap¬ plied to the throwing of shot, and other projectiles, and the blasting of rocks. When a ball is thrown from a gun, the greatest force is applied to it, by each particle, at the moment of its explo¬ sion. But, since the ball cannot, at once, acquire the same velocity, with which the elastic fluid, if at liberty, would expand, it continues to be acted upon by the fluid, and its motion is accelerated, in common cases, until it 132 moving forces used in the arts. has escaped from the mouth of the piece. The acceler¬ ating force, however, is not uniform ; and, hence, the fol¬ lowing circumstances deserve attention. 1. The elasti¬ city is, inversely, as the space which the fluid occupies ; and, therefore, as it forces the ball out of the gun, it con¬ tinually diminishes. 2. The elasticity would diminish, in this ratio, even if the temperature remained the same ; but It must diminish, in a much greater ratio, because a re¬ duction of temperature takes place, both from the disper¬ sion of the heat, and the absorption of it, by the fluid it¬ self, during its rarefaction. 3. The fluid propels the ball, by following it, and acts with a force that is, other things being equal, proportionate to the excess of its velocity, above the velocity of the ball. The greater the velocity that the ball has acquired, the less, therefore, is its mo¬ mentary acceleration. 4. From this change of relative velocity, there must be a period, when the velocity of the ball will exceed that of the elastic fluid ; and, therefore, the proper length for a gun must be that, in which the ball would leave the mouth, at the time when the velocities are equal; and all additional length of the piece, beyond this, can only serve to retard the ball, both by friction, and atmospheric pressure. The force of fired gunpowder is found to be very near¬ ly proportionate to the quantity employed ; so that, if we neglect to consider the resistance of the atmosphere, then the height to which the ball will rise, and its gi’eatest hor¬ izontal range, must be, directly, as the quantity of powder, and, inversely, as the weight of the ball. Count Rurn- ford, however, found, that the same quantity of powder exerted somewhat more force upon a large ball, than on a smaller one. Properties of a Gun .—The essential properties of a gun are, to confine the elastic fluid, as completely as pos¬ sible, and to direct the course of the ball to a rectilinear path ; and hence arises the necessity of an accurate bore. The loindage^ or space, produced by the diflerence of diameter between the ball and the bore, greatly diminishes the effect of the powder, by allowing a part of the elastic fluid to escape, before the ball. The advantage of a rifle PROPERTIES OF A GUN. 133 barrel is chiefly derived from the more accurate contact of the ball with its cavity. When the bore is twisted, it is also supposed to produce a rotation of the ball round an axis, in the direction of its motion, which renders it less liable to deviate from its path, on account of irregularities in the resistance of the air. The usual charge of powder is one fifth, or one sixth, of the weight of the ball ; and, for battering, one third. When a twenty-four pounder is fired, with two thirds.of its weight of powder, it may be thrown about four miles ; the distance being reduced, by the resistance of the air, to about one fifth of that, which it would describe, if thrown in a vacuum.* It is certain, that the grains of gunpowder do not in¬ flame at once, but that the inflammation occupies time, in being communicated from one particle to another ; so that they act, successively, rather than simultaneously, in im¬ pelling tlie ball. This circumstance contributes, greatly, to the safety of fire-arms ; for, if the whole charge of powder exploded at once, the piece would be in danger of bursting, before the inertia of the ball would be over¬ come. It is on account of the suddenness of their deto¬ nation, that the various fulminating powders are inappli¬ cable to use, in fire-arms. The bursting of a gun may be occasioned, by the defective condition of the metal, the disproportionate amount of the charge, the adhesion and inertia of the shot, or the inertia of some other body, op¬ posing the escape of the charge. It is from this last cir¬ cumstance, that a gun is liable to burst, if fired with its mpzzle under water. To enable gunpowder to exert its full effect, the pro¬ portions of the cavity of the piece, to the charge, should i)e such, as to allow all the grains to explode, before tliey leave the cavity ; and, also, to permit the elastic fluid to expend as much of its pressure, as is capable of acceler¬ ating the ball. The superiority of a musket, over a pis¬ tol, arises from its prolonging the action of the powder in this way. But, for reasons already stated, there are lim¬ its to the length of the barrel, which cannot be usefully II. * Young’s Natural Philosophy, vol. i. p. 350. * 12 XII. 134 MOVING FORCES USED IN THE ARTS. exceeded ; and these have been nearly settled, by com¬ mon practice. Blasting. —The splitting of rocks, by gunpowder, is performed by drilling holes, to a certain depth, and in¬ serting a charge of powder, at the bottom. The hole is then filled up, by ramming in fragments of stone, bricks, or other hard substances, keeping in a steel wire, which is afterwards withdrawn, to furnish a passage for the prim¬ ing, by which fire is communicated to the charge. To prevent the danger of a spark, copper wire is often used, instead of steel. And, to prevent the small fragments from flying about, it is found useful to cover the rocks with brush-wood, or some other elastic substance. Rocks may be blasted, at a considerable depth under water, by means of the diving-bell, which enables work¬ men to drill and charge them in safety. In the method practised at Howth, in Ireland, after the charge is insert¬ ed, a tin tube is carried up from the rock, to the surface of the water. It is kept empty, and made water-tight, by screwing the joints to each other, as the bell ascends. The powder is ignited, by dropping pieces of red-hot iron, through the tube, from a boat at the surface. When the depth exceeds twelve feet, no danger or inconvenience is experienced by the boats, beyond a violent, eruptive, ebul¬ lition of the water. Magnetic Engines. —Since the discovery of electro- , magnetism, by aid of which, very powerful magnets have been obtained, various persons have introduced machines, which revolve, and act upon a small scale, by magnet¬ ic power. But a radical difficulty has hitherto attended them, that the magnetic force acts at distances, so ex¬ tremely small, and diminishes, in such a rapid ratio, as the distance increases, that these machines have not been found convertible to any very important use. Works of Reference.—Smeaton’s Miscellaneous papers, 4to. 1814 ;— Robison’s Mechanical Philosophy, vols. ii. and iii. ;— Gregory’s Mechanics ;— Brewster’s Ferguson’s Mechanics ;— Nicholson’s Op'^rative Mechanic, 8vo. ;— Farey’s Treatise on the Steam Engine, 4tG 1827 ; this is the most extensive work, on its sub¬ ject ;— Tredgold, on the Steam Engine, 4to. 1828 ; this is the most philosophic work, on the subject ;— Stuart, on the Steam Engine, ARTS OF CONVEYING WATER. 135 ?vo. 1824 ;— Partingdon, on the Steam Engine, 8vo. 1826 ;—■ Renwick, on the Steam Engine, 8vo. New York, 1830 ;— Bosstjt, Traite Theoretique et Experimental d' Hydrodynamique, 1771 ;— Du Buat, Trailed' Hydraulique, &c. 1786, &c. ;— Playfair’s Outlines of Natural Philosophy, 8vo. 1819 ;— Ure’s Dictionary of Chemistry ;—Works of Coulomb, Desaguliers, De La Hire, Deparcieux, Hutton, Robins, Rumford, &c. CHAPTER XVII. ARTS OF CONVEYING WATER. OJ Conducting Water, Aqueducts, W.iter Pipes, Friction of Pipes, Obstruction of Pipes, Syphon. Of Raising IFater, Scoop Wheel, Persian Wheel, Noria, Rope Pump, Hydreole, Archimedes’ Screw, Spiral Pump, Centrifugal Pump, Common Pumps, Forcing Pump, Plunger Pump, De La Hire’s Pump, Hydrostatic Press, Lifting Pump, Bag Pump, Double-acting Pump, Rolling Pump, Eccentric Pump, Arrangement of Pipes, Chain Pump, Schemnitz Vessels or Hunga¬ rian Machine, Hero’s Fountain, Atmospheric Machines, Hydraulic Ram. Of Projecting Water, Fountains, Fire Engines, Throwing Wheel. The employment of water, as an agent for producing motion, has already been considered. It remains to at¬ tend to the various modes, by which this fluid may be conveyed, from one place to another, either for use in the arts, or for application to the necessary purposes of life. The principal circumstances which require attention, un¬ der this head, are the following. 1. The conducting of water, from one place to another, having the same, or a lower, level. 2. The raising of water, to a higher level. 3. The projection of water, through the atmosphere. OF CONDUCTING WATER. Aqueducts .—When water flows in a current, or stream, as in rivers or canals, it does so in obedience to gravita¬ tion, and in consequence of the surface being lower at the end towards which it is flowing, than in that from which it proceeds. Its motions are governed by laws, some¬ what different from those of solid bodies, descending upon 136 ARTS OF CONVEYING WATER. inclined planes, and this difference is owing to the want of cohesion among the particles. Instead of moving si¬ multaneously, the particles continually change their rela¬ tive position; so that, while one portion of the fluid may be moving rapidly, another may be stationary, or even moving, by an eddy, in a contrary direction. The motion, however, will continue, both in open channels, and in properly constructed pipes, until an equilibrium is pro¬ duced, by the surface, at both ends of the channel, arriving at the same level. Aqueducts are artificial chan¬ nels, or conduits, for the conveyance of water, in a hori¬ zontal, or descending, direction. The aqueducts, con¬ structed by the ancient Romans, were among the most costly monuments of their arts. Several of these were from thirty to a hundred miles in length, and consisted of vast covered canals, built of stone. They were carried over valleys, and level tracts of country, upon arcades, which were sometimes of stupendous height and solidity. A similar method has been practised, in some modern cities, of warm, or temperate, climates. In colder latitudes, if the course of the aqueduct is above the ground, the water is liable to be interrupted, by freezing, in winter. It has, therefore, become common, to resort to subterranean passages for water, which are placed so deep, as to be below the reach of frost, and are, also, favorably situated, both for convenience and econ¬ omy. Culverts, and drains, which are intended merely to remove and expend water, are usually made of brick, or stone ; but, for conveying water with the smallest expenditure by loss, water-pipes are most frequently re¬ sorted to. Water Pipes .—The pipes, by which water is conveyed beneath the ground, are, generally, of small, or moderate, size, and are intended to be water-tight. In consequence of a well-known law of fluids, a water-pipe may possess any degree of flexure, and any number of curvatures, be¬ low the level of the fountain-head ; yet, if it be not ob¬ structed by air, or any other internal obstacle, it will rise, at the discharging end, and may be delivered, at the height of the original level. Pipes, for transmitting water, have IRON PIPES. 137 been made from a great variety of materials.* It is desir¬ able that they should possess strength, tightness, and du¬ rability, and that the material, of which they are composed, should not be capable of contaminating the water. Wood¬ en pipes are, commonly, hollow logs, perforated, by boring through their axis, and connected together, by making the end of one log conical, and inserting it into a conical cav¬ ity in the next. When large trunks are required, they are composed of thick staves and hoops, like a cask. They should, where practicable, be imbedded in clay, and buried at a greater depth, than the frost is ever known to penetrate. Wooden pipes are in common use, in this country, but are liable to decay, especially at the joints, where their thickness is smallest. In salt marshes, they are more durable, though still liable to decay, from the attrition, and decomposing effect, of the water within them. Iron pipes are, at the present day, considered prefera¬ ble to those of wood, being stronger, and, in most situa¬ tions, more durable. They are made of cast-iron, with a socket, or enlarged cavity, at one end, into which the end of the next pipe is received. The joints, thus form¬ ed, are rendered tight, either by filling the interstices with lead, or by driving in a small quantity of hemp, and fill¬ ing the remainder of the socket with iron cement, made of sulphur, muriate of ammonia, and chippings of iron. Copper pipes are extremely durable, and are made of sheet copper, with the edge turned up, and soldered. They require to be tinned, inside, on account of the poison¬ ous character of some of the compounds, which are liable to be formed in them. Lead pipes are much employed, for small aqueducts, owing to the facility with which they can be soldered, and bent in any direction. Tiiey are com¬ monly cast in short pieces, and afterwards elongated, by drawing them through holes, in the same manner as wire. Leaden pipes, in general, are supposed not to contaminate the water contained in them, because the carbonate of * It appears, that the use of water-pipes was not unknown to the ancients. Some rules, respecting the use of leaden and earthen pipes are given by Vitruvius de Architectura, Lib. viii. 12 * 138 ARTS OF CONVEYING WATER. lead, which is sometimes formed in them, is insoluble in water. They are not safe, however, for pumps and pipes, intended to convey acid liquors. Stone pipes preserve the water, contained by them, in a very pure state. They are, however, expensive, on account of the labor of work¬ ing them, with the exception of soap-stone, which, being easily shaped and bored, may be usefully applied to the purpose of conveying water, in those places where it is easily procured. Earthen pipes^ made of common pottery ware, and glazed on the inside, are sometimes used, but are more liable to be broken, than most of the other kinds. Friction of Pipes .—In a river, or open channel, it is observable, that the w'ater flows most rapidly, in the mid¬ dle of the upper surface, while it is most retarded, at the edges, and at the bottom. In like manner, in a cylin¬ drical pipe, the fluid has the greatest velocity, at the cen¬ tre, or axis, and the smallest velocity, at the surface, or where it is in contact with the pipe. The force, by which this retardation is occasioned, is commonly called fric¬ tion. It differs, in many respects, from the friction of solids ; and more resistance is occasioned, hy the internal action of the fluid particles upon each other, than by the contact of the solid surface, in which they are contained. The investigation of the laws which govern the move¬ ments of fluids is intricate, and the results of experiment have not agreed with the previous conclusions of theory. Various writers, on the science of hydraulics, have treated this subject with an extensiveness of research, which can only be understood from their own works. Among the more simple, practical, facts, to which it is useful to at¬ tend, the following may be briefly stated. 1. The veloci¬ ty of water is greater in a large pipe, than in a small one, having the same position ; and hence, a large pipe will discharge more water, in a given time, than a number of small ones, having, jointly, the same capacity. A pipe, of two inches diameter, will give more water, than five pipes, of one inch diameter ; it being ascertained, that the squares of the discharges are, very nearly, as the fifth pow¬ ers of the diameters.* 2. Irregularities and inequalities, * llobisou’s Mechanical Philosophy, vol. ii. p. 578. OBSTRUCTION OF PIPES. 139 ill the diameter of the jiipe, diminish the amount of water which tliey transmit, by altering the direction of the par¬ ticles, and by changing their velocity, so as to renew the resistance of inertia. 3. In like manner, all curves and angles, which occur in the pipe, have a similar retard¬ ing effect, by creating new motions, or counter currents. 4. The form of the end of the pipe, which communicates with the fountain-head, or reservoir, greatly afiects the (quantity of water received by it. If it be gradually en¬ larged, like a trumpet mouth, a larger quantity of water w ill be received, than by any of the modes which follow, because the direction, given to the particles by this form, is most favorable to their admission. If the entrance to the pipe be abrupt, in consequence of the cavity being w holly cylindrical, the particles will have a tendency to cross each other, and less water will enter the pipe, in a given time. And, if the end of the pipe projects into the reservoir, a variety of opposing forces will be pro¬ duced, among the particles moving toward the entrance ; so that a smaller quantity will be received by the pipe, than in either of the preceding cases. The form of the discharging orifice, also, influences the quantity of water delivered by a pipe, in a given time. If the end of the pipe be enlarged, by adding to it a frus¬ tum of a hollow cone, the amount of water discharged, in some cases, may be prodigiously increased.* This fact, described by Venturi, appears to be the result of the pressure of the atmosphere, aided by the inertia and co¬ hesiveness of the water. Obstruction of Pipes .—Water pipes are liable to be obstructed, chiefly, by the following circumstances. 1. By the freezing of the water, in winter, if the ))ipe has not been laid sufliciently deep. 2. By the deposition of sand and mud, in the lower parts of the pipe. To obvi¬ ate this, the water should pass through a strainer, before it enters the pi])e. And, if plugs are placed at the lower parts of the bendings, then, whenever these are opened, the water rushes out with sufficient rapidity, and carries * Sec Kdinburgh Kncyclopedia, Art. Hydrodynamics, pp. 494, 495 140 ARTS OF CONVEYING WATER. the deposition with it. 3. By the penetration of roots, or the growth of aquatic vegetables, in the cavity of the pipa This principally happens in wooden pipes, after they begin to decay. 4. By the collection of air, in the upper parts of the bendings. This is a serious evil, and may take place in all pipes, which have an undulating course, or more vertical curvatures than one. When air is thus confined in the pipes, the water will not rise to the same height, at the discharging end, as at the fountain head. The air, being the lighter fluid, tends to occupy the highest part of the bendings. Any pressure, applied at the fountain-head, tends to push this air a little beyond the highest part, so as to make it occupy a portion of the descending side of the curve. Of course, the sura of the weights, in the descending sides, will be less than the sura of the weights, in the ascending sides, and the fluids will not be in equilibrium, except when the water, at the foun¬ tain-head, is higher than that at the discharging end. The conditions, upon which this equilibrium is produced, are the same as those which sustain the fluid, at different lev¬ els, in Hero’s fountain, the spiral pump, and the hydro¬ static lamp. The prevention of this evil consists, in avoiding ver¬ tical curves, and in laying the pipe, if possible, with an uninterrupted slope, or, at least, with only one slope in each direction. When this is done, the air will escape at one, or both, ends of the pipe. But, when vertical curves are unavoidable, an open tube, the height of which is equal to that of the fountain-head, should be attached to the highest part of the curve. By this arrangement, the air will readily escape. In like manner, if a tight air- box be fastened upon the upper part of the curve, and filled with water, the air will escape into this box, and displace the water, without interrupting the current in the pipe. The air-box may be made to regulate itself, and to discharge the air, when it is full, by means of a valve in the top, connected with a floating, hollow, copper ball. As the air increases, the copper ball will subside with the water, till it opens the valve, for the air to escape. In Fig. 160, AB, represents an undulating pipe, of which SYPHON. HI Fig. 160 . C A D C A, is the fountain-head, and B, the discharging end. The water and air will arrange themselves, as represented by the darker and lighter parts of the tube, and, being in equilihriiun, no water will be discharged. If an up¬ right tube, C, be attached to either of the upper flex¬ ures, it will discharge the air from that flexure. Or, if a tight box, or vessel, 1), be substituted, with a copper float and valve, it will have a similar effect. Simple punctures, made in the upper part of the pipe, also answer a temporary purpose. Syphon .—The syphon may be regarded as an instru¬ ment for the lateral conveyance, rather than the rising, of water ; since the fluid must always be delivered, at a low¬ er level than that at which it is received. The syphon is a bent tube, of which one extremity, or leg, is longer than the other. If the shorter leg be inserted in a fluid, and the air be exhausted from the longer leg, by suction, or otherwise, till the syphon is full of water, then the col¬ umn of fluid in the longer leg will preponderate, and the current will take place. Tliis will continue, either till the water, in the feeding vessel, sinks below the end of the syphon, or that in the receiving vessel rises to the same height with the other. As the movement depends upon the pressure of the atmosphere, water cannot be raised, in a syphon, to a greater height than thirty-four feet. For practical use, the longer leg of the syphon is often closed with a stop-cock, and the air exhausted from it, by a small pump, till the leg is full. The stop-cock is then opened, and the fluid immediately flows through the sy¬ phon. 142 ARTS OF CONVEYING WATER. OF RAISING WATER. The lateral conveyance of water is effected, in the inodes already described, by the aid of its own gravity, '.['he raising of water is effected, against gravity, by the employment of some moving force. Hydraulic machines, for raising water, may be impelled by a current, or fall, of the water itself, or by any other moving agent. Among a great variety of machines, which have been constructed , for this use, the following are some of the most noticeable. ^coop Wheel .—If a water-wheel is provided with a^ hollow axle, and if, in the place of spokes, or radii, it is furnished with crooked tubes, or cavities, of a suitable curvature, it will raise water to the height of its own axis, whenever it revolves in the direction of the mouths of the tubes. Each spoke, or curved tube, as it dips its extremity in the water, lifts a certain portion of the fluid ; and, as the revolution continues, this water will flow through the tube, approaching nearer to the axis, until it is discharged into the central hollow. To prevent the water from regurgitating, the inner ends of the tubes must be guarded by valves, or else made to project, for a short distance, into the central cavity, as seen at A, in Fig. 161. In the latter case, it is necessary, that they Fig. 161. should enter, at different distances from the end of the axle. The axle may also be divided into as many lon¬ gitudinal compartments, as there are tubes in the wheel. PERSIAN WHEEL.-NORIA.-ROPE PUMP. 14J This was clone in the ancient tympanum, a machine de¬ scribed by Vitruvius, which was somewhat similar, in its principle, to the scoop-wheel. Persian Wheel .—The Persian wheel, in certain re¬ spects, resembles the scoop-wheel, and is sometimes combined with it, in the same machine. It differs from it, in its effect, by raising the water through the whole di¬ ameter of the wheel. Its form is easily understood, by supposing a number of buckets to be hung round the cir¬ cumference of a water-wheel, upon pivots, at equal dis¬ tances. As the wheel turns, the buckets are successively immersed in the water, at the bottom, and filled. They then pass upwards, till they arrive at the top of the W'heel, where they strike a fixed obstacle, and are overset, dis¬ charging their water into a trough, placed at the top, to receive it. This machine is said to be in common use, in several of the Oriental countries. JS^oria .—The machine used in Spain, under the name of noria, consists of revolving buckets, like the Persian wheel. But, instead of a single wheel, two drums, or trundles, are employed, and the buckets are attached to ropes, or chains, passing round them. In Spain, earthen pitchers are said to be used ; but, in other countries, wooden buckets are employed, like those of an over¬ shot-wheel. A sufficient idea of the form of the noria may be obtained, by inspecting the figure of the cliain- wheel, on page 89, and sujqiosing the motion reversed. Rope Pump .—Instead of a series of buckets, connec¬ ted by ropes, or chains, a similar effect is, sometimes, pro¬ duced by a simple rope, or a bundle of ropes, passing over a wheel above, and a pulley below, moving with a velocity of about eight or ten feet in a second, and draw¬ ing up a certain quantity of water, by its friction. It is probable, that the water commonly ascends, with about half the velocity of the rope. While the water is, prin¬ cipally, supported by the friction of the rope, its own co hesion is sufficient to prevent it from wholly falling, oi being scattered, by any accidental inequality of the mo¬ tion. The portion raised is collected in a trough, at the top. 1 144 ARTS OP CONVEYING WATER. Hydreole .—This name is given by M. Mannoury Dectot, to an invention for raising water, by the admix¬ ture of atmospheric air. If a column of water be inti¬ mately mixed with air, in small bubbles, the air will oc cupy sotfte time in ascending to the surface; and the meanwhile, the collective specific gravity of the whole column will be much less, than if it consisted of water alone. If a vertical tube be placed in a reservoir of wa¬ ter, and if a quantity of air be injected into the bottom of the tube, by a bellows, or forcing pump, the water in the tube will immediately rise to a higher level, and remain, until the air has escaped at the top. And, if the tube be of proper height, the water will overflow, in the same manner as it does during the ebullition of boiling liquids. This appears, however, not to be a very economical mode of applying force. Archimedes'’ Screw .—This name is given to a machine, formed by one or more pipes, wound spirally round a cylinder, which revolves on an axis, in an oblique situa¬ tion. It is used, in some places, under the name of wa¬ ter-snail. Its mode of operation may be easily conceiv¬ ed, by supposing a tube, formed into a hoop, to be rolled up aq inclined plane, in which case, the fluid would be forced, by the elevation of the tube behind it, to run, as it were, up hill. The screw is usually turned, by a water¬ wheel. During each revolution, the lower end of each spiral tube is immersed in the water, and dips up a cer¬ tain quantity. This water, by its gravity, keeps to the lower side of the screw, as seen in Fig. 162 ; but, at the Fig. 162. WATER-SCREW.-SPIRAL PUMP. 145 same tune, in consequence of the rev'olutions of the screw, it passes continually upward, until it is delivered, at the highest end. This instrument is sometimes made, by fixing a spiral partition round a cylinder, and covering it with an exter¬ nal coating, either of wood, or of metal. It should be so placed, with respect to the surface of the water, as to fill, in each turn, one half of a convolution ; for, when the orifice remains always immersed, its effect is much diminished. It is generally inclined to the horizon, in an angle of between forty-five and sixty degrees ; hence it is obvious, that its utility is limited to those cases, in which the water is only to be raised to a moderate height. 'I'he spiral is seldom single, but usually consists of three or four separate coils, forming a screw, which rises, more rapidly, round the cylinder. A icater-screw, which operates in a similar manner, may be made, by a spiral partition, wound upon a central axis, and revolving, by itself, within a smooth hollow cylinder, to the cavity of which it is nearly fitted. In this form, however, there is some loss, by the leakage between the screw, and the cylinder which contains it. Spiral Pump .—This machine is formed, by a spiral pipe, consisting of many convolutions, arranged either in a single plane, as in Fig. 163, or in a cylindrical, or con- Fig. 16.3. leal, surface, and revolving round a horizontal axis. The pipe is connected, at one end, by a central water-tight joint, to an ascending pipe, while the other end receives, during each revolution, nearly equal quantities of air and n. 13 XII. 146 ARTS OF CONVEYING WATER. water. It was invented, about 1746, by Andrew Wirtz, a pewterer, at Zurich; whence it is often called the Zu¬ rich machine. It is said to have been used, with great success, at Florence, and in Russia. Dr. Young states, that he has made use of it, for raising water, to a height of forty feet. The end of the pipe is furnished with a spoon, containing as much water as will fill half of one of its coils. The water enters the pipe, a little before the spoon has arrived at its highest situation, the other half remaining full of air. The air communicates the pres¬ sure of the column of water to the preceding portion ; and, in this manner, the eflect of nearly all the water in the wheel is united, and becomes capable of supporting the column of water, or of water mixed with air, in the ascending pipe. The air, nearest the joint, is compressed into a space, much smaller than that which it occupied at its entrance ; so that, where the height is considerable, it becomes advisable to admit a larger portion of air than would, naturally, fill half the coil. This lessens the quan¬ tity of water raised, but it lessens, also, the force requir¬ ed to turn the machine. The joint should be conical, in order that it may be tightened, when it becomes loose ; and the pressure ought to be removed from it, as much as possible. The loss of power, supposing the machine well constructed, arises only from the friction of the wa¬ ter on the pipes, and the friction of the wheel on its axis ; and, where a large quantity of water is to be raised to a moderate height, both of these resistances may be ren¬ dered inconsiderable. But, when the height is very great, the length of the spiral must be much increased, so that the weight of the pipe,becomes extremely cumbersome, and causes a great friction on the axis, as well as a strain on the machinery. Centrifugal Pump .—The centrifugal force has some¬ times been employed, in conjunction with the pressure of the atmosphere, as an immediate agent, in raising wa¬ ter, by means of a rotary pump. The machine, called centrifugal-pump, consists of a vertical pipe, capable of revolving round its axis, and connected, above, with a hor¬ izontal pipe, which is open at one, or at both, ends ; the COMMON PUMPS. 147 whole being furnished with proper valves, to prevent the escape of the water, when the machine is at rest. As soon as the rotation becomes sufficiently rapid, the cen¬ trifugal force of the water, in the horizontal pipe, causes it to be discharged, at the ends, its place being supplied, by means of the pressure of the atmosphere on the reser¬ voir below, which forces the water to ascend, through the vertical pipe. This machine may be so arranged, that, according to theory, very little of the force applied is lost ; but it has failed of producing, in practice, a very advantageous effect. In Fig. 1G4, a centrifugal pump is Fig. 164. represented. The machine is first filled witn water, through the funnel. A, while the valve, at D, prevents the water from descending. The whole is then made to turn rapidly, and the water is discharged, from the ends of the horizontal part, into a circular trough, a section of which is seen at B, and C. C___—-— Common Pumps .—A pump is a machine, so well known, and so generally used, that the denomination has sometimes been extended to hydraulic machines of all kinds. The term, however, in its strictest sense, is to be understood of those macliines, in which the water is raised, by the motion of one solid within another ; and this motion is usually alternate, but sometimes continued, so as to constitute a rotation. In the pumps most com 148 ARTS OF CONVEYING WATER. monly used, a cavity is enlarged and contracted, by turns, the water being admitted into it through one valve, and discharged through another. The common household-pump has otherwise been call¬ ed the sucking-pump, from the circumstance, that the water is raised in it, by the pressure of the atmosphere. In this country, pumps are made for common use, both in wells, and in ships, by boring logs, so as to produce a large hollow, and inserting two hollow wooden plugs, cal¬ led boxes, at different heights, both of which are furnish¬ ed with valves, or clappers, opening upwards. The lower box is made stationary, and serves merely to pre¬ vent the water, which is raised, from running back. The upper box is a hollow movable piston, attached, by its rod, to the handle, or brake, of the pump. When the pump is full of water, every stroke of the handle raises this box, together with the column of water above it. When the handle is lifted, the box is pushed further down into the water, while its valve opens, to allow the water to pass through. In Fig. 165, this pum^p is represented. Fig. 165. with the box just beginning to descend. The valve then shuts, and the second stroke of the pump raises another column of water to the spout. As the action of this pump depends upon the pressure of the atmosphere, wa- FORCING-PUMP.-PLUNGER-PUMP. 149 ter cannot be raised by it, from a depth of more than thir¬ ty-four feet below the upper valve ; and, in practice, a much shorter limit is commonly assigned. Forcing Pump .—The forcing-pump differs from the common sucking-pump, just described, in having a solid piston, without a valve, and the spout, or discharging orifice, placed below the piston. When the piston is raised, the lower valve of the pump rises, and admits the water from below, as in the common pump. But when the piston is depressed, the water is thrown out, through a spout in the side, which has a valve opening outward, at [a,] in Fig. 166. In a forcing-pump, the water cannot Fig. 166. t a be brought from a depth, of more than thirty-four feet be¬ low the piston ; but it can afterwards be sent up, to any height desired, in a pipe, [«6,] because the pressure, com¬ municated by the downward stroke of the piston, is not dependent on the pressure of the atmosphere, but upon the direct force applied to the piston. Plunger Pump .—A very effectual pump, for raising a large quantity of water, to a small height, is shown in Fig. 167, on the following page. It is made, by fitting two upright beams, or plungers, A and B, of equal thickness, throughout, into cavities, 13* 150 ARTS OF CONVEYING WATER. Fig. 167. D C nearly of the same size, allowing them only room to move without friction, and connecting the plungers together, by a horizontal beam, moving on a pivot. The water being admitted, during the ascent of each plunger, by a large valve, in the bottom of the cavity, at C and D, it is forced, when the plunger descends, to escape through a second valve, at E or F, in the side of the cavity, and to ascend, by a wide pipe, to the top of the machine. The plungers ought not to be, in any degree, tapered ; be¬ cause, in this case, a great force would be unnecessarily consumed, when they descend, in throwing out the water, with great velocity, from the interstice formed by their elevation. This pump may be worked by a laborer, walking backwards and forwards, either on the beam, or on a board, suspended below it. By means of an ap¬ paratus of this kind, described by Professor Robison, an active man, loaded with a weight of thirty pounds, has been able to raise five hundred and eighty pounds of water, every minute, to a height of eleven and a half feet, for ten hours a day, without fatigue. This, says Dr. Young, is the greatest effect produced by a laborer, that has ever been correctly stated, by any author ; it is equivalent to somewhat more than eleven pounds, raised through ten feet, in a second, instead of ten pounds, which is a fair estimate of the usual force of a man, without any deduc¬ tion for friction. 151 DE LA hire’s pump. De La Hire's Pump .—A pump, partaking of the nature of a forcing and a sucking pump, is sometimes called a mixed pump. In De La Hire’s pump, which is of this kind, and shown in Fig. 168, the same piston is made to serve Fig. 168. a double purpose ; the rod working in a collar of leathers, and the water being admitted and expelled, in a similar manner, above and below the piston, by means of a double apparatus of valves and pipes. When the piston is de¬ pressed, the water enters the barrel at the valve. A, and goes out at B. When the piston is elevated, it enters at C, and escapes at D. For forcing-pumps, of all kinds, the common piston, with a collar of loose and elastic leather, is preferable to those of a more complicated structure. The pressure of the water, on the inside of the leather, makes it sufficiently tight, and the friction is inconsiderable. In some pumps, the leather is omitted, for the sake of simplicity, the loss of water being compensated by the greater durability of the pumps ; and this loss will be the smaller, in propor¬ tion, as the motion of the piston is more rapid. Hydrostatic Press .—This powerful machine is essen¬ tially a forcing-pump, aided, in its action, by the well-known properties of hydrostatic pressure. It appears to have been invented by Pascal, previously to 1664, and recom¬ mended by him, as a new mechanical power. It was, however, practically, lost sight of, till it was re-invented by 152 ARTS OF CONVEYING WATER, Mr. Bramah, more than a century afterwards. In this press, the water is forced, by a small pump, into a strong iron cylinder, in which it acts on a much larger piston ; consequently, this piston is urged by a force, as much greater than that which acts on the first pump-rod, as its surface is greater than that of the small one. In Fig. 169, the water is forced, by the pump. A, through thfe Fig. 169. pipe, B, into the cylinder, C, in which it acts, very pow¬ erfully, upon the large piston, D, and raises the bottom of the press, E. The upward force, by which the material, above E, is compressed, exceeds the force, which is ap¬ plied to the pump, as much as the surface of the piston, D, exceeds that of the piston of the pump. In practice, the cylinder, C, requires to be made much thicker than here represented. . Lifting Pump .—Where the height, through which the water is to be raised, is considerable, some inconvenience might arise, from the length of the barrel, through which the piston-rod of a sucking-pump would have to descend, in order that the piston might remain within the limits of atmospheric pressure. This maybe avoided, by placing the movable valve, below the fixed valve, and introducing the piston, at the bottom of the barrel. It is then w'orked, by means of a frame, on the outside. Such a machine is called a lifting-pump. In common with other forcing- pumps, it has the disadvantage of thrusting the piston be¬ fore the rod, and thus tending to bend the rod, and pro¬ duce an unequal friction on the piston, while, in the suck- BAG-PUMP.-DOUBLE-ACTING PUMP. 153 ing-pump, the principal force always tends to straighten the rod. Bag Pump .— A bag of leather has sometimes been employed, for connecting the piston of a pump with the barrel, and, in this manner, nearly all friction is avoided. It is probable, however, that the want of durability would be a great objection to such a machine. In Fig. 170, A, Fig. 170. represents a leathern bag, attached to a number of hoops. This bag is alternately extended and contracted, like a bellows, by every stroke of the piston, and raises the wa¬ ter, without friction against the pump.....-—--— Double-acting Pump .—The rod of a sucking-pump, may also be made to work in a collar of leather, at the top, as at A, in Fig. 171, and the water may be forced 154 ARTS OF CONVEYING WATER. through a vake, into an ascending pipe, B. By applying an air-vessel to this, or to any other, forcing-pump, as is done in fire-engines, its motion may be equalized, and its performance improved ; for, if the orifice be large enough, the water may be forced into the air-vessel, during the stroke of the pump, with any velocity that may be re¬ quired, and with little resistance, from friction ; whereas, the loss of force, from the frequent accelerations and re¬ tardations of the whole body of water, in a long pipe, must always be considerable. The condensed air, re¬ acting on the water, expels it more gradually, and in a continual stream, so that the air-vessel has an effect, anal¬ ogous to that of a fly-wheel, in mechanics. Fig. 172. 1 / W X Rolling Pump .—A pump of this kind is formed, by a barrel, or hollow cylinder, shown in section, in Fig. 172, having two partitions. One of these, AB, is fixed, and the other, CD, is composed of two wings, or valves, ca¬ pable of an alternate motion, about the axis of the cylin¬ der. When the partition, CD, turns in one direction, the water, in the cavity, C, is driven out at the orifice, [a,] and will rise in a pipe, attached to that orifice. At the same time, the water, in the cavity, D, is forced out at the orifice, [d]. While this is taking place, fresh por¬ tions of water enter the remaining cavities, [at w and z]. When the partition, CD, has moved, as far as possible, it then returns, in the opposite direction, and drives out the water, through [y and a;,] and receives fresh water, through [6 and c]. The orifices, which receive the water, have valves, opening inward, and those, which dis¬ charge it, have valves, opening outward. The machine ECCENTRIC-PUMP. 155 is worked by arms, attached to the axis of the cylinder, which, for this purpose, projects through a collar, in the ends of the vessel. For the sake of simplicity, a sector of a cylinder is sometimes used ; in which case, a single partition, or valve, like a door on hinges, traverses the whole cavity, and only half the number of orifices are necessary, to ad¬ mit and discharge the water. Fire-engines, for project¬ ing water, have been constructed, in both these methods, by different inventors. Fig. 173. Eccentric Pump .—The eccentric pump, a section of which is shown at Fig. 173, consists of a hollow cylinder, [ad,] in the interior of which, a solid cylinder, [6,] of the same length, but of about half the diameter, is made to revolve, by its axle, passing through water-tight collars, in the ends of the exterior cylinder. The internal cyl¬ inder is so placed, that its surface comes in contact with some part of the internal surface of the larger cylinder. The surface of the small cylinder, is also furnished with four large valves, or flaps, turning on hinges, and par¬ taking of its own curvature ; so that, when they are shut down, they form no projections, but appear as parts of the same cylinder. These valves are made to open, by springs, or otherwise ; so that, wdien one of them is brought, by the revolution of the internal cylinder, into the narrowest part of the internal space, it is pressed down, and shut; but, as the inner cylinder moves on, the 156 ARTS OF CONVEYING WATER. valve, being gradually carried forward, will continue to open, until it arrives at the widest part of the cavity. It is then pressed down again, by a continuation of the rev¬ olution. In this way, the water behind the valve is drawn up, from the feeding-pipe, by the atmospheric pressure, while that before the valve is forced upward, into the delivering pipe. As each of the valves performs the same operation, in its turn, this pump affords a constant supply of water. Rotative steam-engines have been constructed, by dif¬ ferent projectors, on the principle of this pump, as well as the following. Fig. 174. Another form of an eccentric pump, is seen in Fig. 174. The roller, or solid cylinder, A, revolving within the reservoir, or hollow cylinder, BF, carries with it the slider, DE, which is made to sweep the internal surface of this cylinder, by revolving, in the direction from C to F, so that the water is drawn up, by the pipe, C, and dis¬ charged, by the pipe, F. An objection to all pumps of this sort is, that, if they are made tight enough to hold water, they occasion a great degree of friction, on account of the extensive con¬ tact of the moving surfaces. The continual change, also, which takes place, both in the direction and velocity of the water, is productive of great resistance from inertia. The stream, at the delivering orifice, although never whol¬ ly intermitted, is, by no means, uniform in its velocity._ Arrangement of Pipes .—The pipes, through which wa¬ ter is raised, by pumps of any kind, ought to be as short, and as straight, as possible. Thus, if we have to raise CHAIN-PUMP, ETC. 157 water, to a height of twenty feet, and to carry it, to a hor¬ izontal distance of one hundred, by means of a'forcing- pump, it will be more advantageous to raise it first, ver¬ tically, into a cistern, twenty feet above the reservoir, and then to let it run along horizontally, or find its level in a bent pipe, than to connect the pump immediately with a single pipe, carried to the place of its destination. And, for the same reason, a sucking-pump should be placed as nearly over the well as possible, in order to avoid a loss of force, in working it. If very small pipes are used, they will much increase the resistance, by the friction which they occasion. Chain Pump. —Water has sometimes been raised by stuffed cushions, or by oval blocks of wood, connected with an endless rope, or chain, and caused, by means of tw’o wheels, or drums, to rise, in succession, in the same uarrel, carrying the water in a continual stream before them. The magnitude, however, of the friction, appears to be an objection to this method. From the resemblance of the apparatus to a string of beads, it has been called a head-pump., or paternoster-uork. When flat boards are united by chains, and employed, instead of these cushions, the machine has been denominated a cellular pump ; and, in this case, the barrel is usually square, and placed in an inclined position. There is, however, a considerable loss, from the facility with which the water runs back. The chain-pump, used in the Navy, is a pump of this kind, with an upright barrel, through which leathers, strung on a chain, are drawn in constant succession. These pumps are only employed, when a large quantity of water is to be raised, and they must be worked with considera¬ ble velocity, in order to produce any effect at all. The Chinese work their cellular pumps, or bead- pumps, by walking on bars, which project from the axis of the wheel, or drum, that drives them ; and, whatever objection may be made to the choice of the machine, the mode of communicating motion to it, must be allowed to be advantageous. Schemnitz Vessels, or Hungarian Machine. —The mediation of a portion of air is employed for raising wa¬ it. 14 XII. 158 ARTS OP CONVEYING WATER. ter, not only in the spiral-pump, but also in the air-ves¬ sels of Schemnitz, in the manner, shown in Fig. 175. A Fig. 175. column of water, descending through a pipe, C, into a closed reservoir, B, containing air, obliges the air to act, by means of a pipe, D, leading from the upper part of the reservoir, or air-vessel, on the water in a second res¬ ervoir, A, at any distance, either below or above it, and forces this water to ascend, through a third pipe, E, to any height less than that of the first column. The air- vessel is then emptied, the second reservoir filled, and the whole operation repeated. The air must, however, acquire a density, equivalent to the pressure, before it can begin to act; so that, if the height of the columns were thirty-four feet, it must be reduced to half its dimensions, before any water would be raised ; and thus, half of the force would be lost. But, where the height is small, the force lost in this manner is not greater, than that which is ' usually spent in overcoming friction, and other imperfec¬ tions, of the machinery employed ; for the quantity of water, actually raised by any machine, is not often greater than half the power which is consumed. The force of the tide, or of a river, rising and falling with the tide, might easily be applied, by a machine of this kind, to the purpose of raising water. Thus, if, at low tide, the ves- hero’s fountain, etc. 159 sel, A, was filled with air, then, at high tide, the water, riowing down the tube, E, would cause the water in the vessel, B, to ascend in the pipe, C. Heroes Fountain .—The fountain of Hero, precisely re¬ sembles, in its operation, the hydraulic vessels of Schem- nitz, which were probably suggested to their inventor, by (he construction of this fountain. It may be used, simply, to raise water, or to project it upwards, in the form of a V>t, as in Fig. 176. The first reservoir, C, of the foun- Fig. 176. lain, is lowe'' ‘han the orifice of the jet. A pipe descends Vom it, to tue air-vessel, B, which is at some distance below, and the pressure of the air is communicated, by rtn ascendi.ig tube, D, to a third cavity, A, containing the water which supplies the jet. in this form of the ma chine, the water will continue to spout from the pipe, E, until all the water in the reservoir, C, has descended into the vessel, B. The principle of Hero’s fountain has been applied, to raise oil in lamps ; and one of its most simple forms has already been described, under the head of Ilydrostaiic Lamp^ page 334, vol. I. ^yi^i^Atmospheric J)Iachincs .—The spontaneous vicissitudes of the pressure of the air, occasioned by changes in the weight and temperature of the atmosphere, have been ap¬ plied, by means of a series of reservoirs, furnished witjp proper valves, to the purpose of raising water, by degrees, to a moderate height. But it seldom happens, that such 160 ARTS OF CONVEYING WATER. changes are capable of producing an elevation in the water of each reservoir, of more than a few inches, or, at most, a foot or two, in a day; and the whole quantity raised must therefore be inconsiderable. Hydraulic Ram .—The momentum of a stream of wa¬ ter, flowing through a long pipe, has also been employed, for raising a small quantity of water, to a considerable height. The passage of the pipe, being stopped by a valve which is raised by the stream, as soon as its mo¬ tion becomes sufficiently rapid, the whole column of fluid must necessarily concentrate its action, almost instantan¬ eously, on the valve. In this manner, it loses the charac¬ teristic property of hydraulic pressure, and acts, as if it were a single solid ; so that, supposing the pipe to be per¬ fectly elastic, and inextensible, the impulse may overcome any pressure, however great, that might be opposed to it. If the valve opens into a pipe, leading to an air-vessel, a certain quantity of the water will be forced in, so as to condense the air, more or less rapidly, to the degree that may be required, for raising a portion of the water, con¬ tained in it, to a given height. Mr. Whitehurst appears to have been the first that employed this method. It was afterwards improved by Mr. Boulton; and the same ma¬ chine has attracted much attention, in France, under the denomination of the hydraulic ram of M. Montgolfier. Fig. 177. Fig. 177, represents this machine. When the water in the pipe, AB, has acquired sufficient velocity, it raises the valve, B, which immediately stops its further passage. The momentum, which the water has acquired, will then OF PROJECTING WATER.-FOUNTAINS. 161 force a portion of it, through the valve, C, into the air- vessel, I). The condensed air, at D, causes the water to rise into the pipe, E, as long as the effect of the horizon¬ tal column continues. When the water becomes quies¬ cent, the valve, B, will open again, by its own weight, and the current will be renewed, until it acquires force enough to shut tlie valve, and repeat the operation. OF PROJECTING WATER. If a degree of force, or pressure, be applied to water, sufficient to raise it, through a tube, to a given height, the same force would also cause it to spout through an ori¬ fice, in a continued stream, or jet, to nearly the same height, in common cases. The height, however, can never be fully as great, for various reasons. One of these is found, in the friction of the ajutage, or discharg¬ ing orifice, which acts as a retarding force. Another obstacle is, the resistance of the atmosphere, which in¬ creases, in a rapid ratio, as the velocity of the water be¬ comes greater, and which is also greatly augmented, as the w'ater divides, and spreads out a greater surface to the resistance of the air. A third obstacle consists, in the resistance which the water offers to itself. The parts first projected, being constantly retarded in their ascent, by gravity, and atmospheric resistance, oppose the pro¬ gress of the parts, which are last projected, and wdiich have the greatest velocity. And, as fluids move, in all directions, this impulse, of different parts of the water, against each other, tends to widen, and, consequently, to shorten, the column. In a vertical jet, moreover, the W'eight of the falling water opposes the ascending col¬ umn ; and, hence, a fluid will spout higher, if the jet be turned a little to one side, than if it be perpendicular. Foimtains .—Artificial fountains, which throw a per¬ petual jet of water, usually act by the pressure of a res¬ ervoir of water, situated at a greater height than that of the jet produced. The water is conveyed from the res ervoir, to the place of the fountain, in pipes ; and, if the orifice, from which it issues, be directed upward, it will spout, to a height approaching that of the reservoir. Jt 14 * 162 ARTS OP CONVEYING WATER. will always, however, fall short of this height, for the reasons already stated ; and the difference will be great¬ er, in jets of great height, than it is in lower ones ; since it is found, by experiment, that the differences between the heights of the jets and of the reservoirs, are as the squares of the heights of the jets themselves.* Foun¬ tains are chiefly used, for purposes of ornament, and, when of large size, require to be fed from the elevated parts of rivers, or bodies of water, having a high level. At Peterhoff, in Russia, there are two fountains, which spout a column of water, nine inches in diameter, to the height of sixty feet, and the fall of the returning water produces a concussion, sufficient to shake the ground. Fire Engines .—The engines used for extinguishing fires, in buildings, are, in effect, a species of forcing pumps, in which the water is subjected to pressure suffi¬ ciently strong to raise it, by a jet, or otherwise, to the re¬ quired height. But, if the forcing pump were used alone, the water would issue only in intermitting jets, in conse¬ quence of the reciprocating motion of the pump, and thus, a great part of it would become ineffectual. In or¬ der to make the discharge uniform, and thus keep up a continual stream, a strong vessel, filled with air, is at¬ tached to the engine. Into this vessel, the water is forced, by the pumps ; and, as the air cannot escape, it is con¬ densed, in proportion as the water accumulates, until it reacts upon the surface of the water, with great power. If the air be condensed, into half the space which it orig¬ inally occupied, it will act upon the water with a pressure, equal to that of two atmospheres, and will be adequate to raise water, tJirough a tube, to the height of thirty-three feet, or to project it, through the atmosphere, to nearly the same height. When the air is condensed, to one third of its former volume, in consequence of the air- vessel being two thirds filled with water, its elasticity will be three times greater than that of the atmosphere. It will therefore raise water, in a tube, to the height of six¬ ty-six feet, and would throw, it to nearly the same height, * Ascertained by Mariotte.— Bossut, Tom. ii. § 615. THRO WING-WHEEL. 1C3 were it not for the resistances, which have already been explained. The foregoing principle of the fire-engine has been variously modified, by adapting different kinds of pumps to the air-vessel, and by altering various details. In the engines of Newsham, and others, two cylinders, con¬ structed like forcing-pumps, are worked by the recipro¬ cating motions of transverse levers, to which the handles are attached. In this way, the water is forced into the air-vessel, from which it afterwards spouts, through a movable pipe. In some other engines, a single cylin¬ der is used, the piston-rod passing through a tight collar, as it does in Watt’s steam-engine, thus alternately receiv¬ ing and expelling the water, at each end of the cylinder. Jn Rowntree’s engine, and some others, a mechanism is used, like that of the rolling-pump, a part of the inside of a cylinder being traversed by a partition, like a door, hinged upon the axis of the cylinder, which drives the water, successively, from each side of the cylinder, into tlie air vessel. A long flexible tube, made of leather, and known among firemen by the name of hose^ is of great use in carrying the spouting orifice near to the flames, and thus preventing the water from being scattered too soon. It also serves an important purpose, in bringing water from distant reservoirs, by suction, created in the pumps of the engine. Tliroicing Wheel .—A throwing-wheel, otherwise call¬ ed a flash-wheel, or fen-wheel, is used for raising water, both by lifting and projecting it. Its structure resembles that of an undershot water-wheel, or, more properly, of a breast-wheel. Its under surface is received in a trough, or channel, which curves upward. When the wheel is made to revolve, it drives the water before it, and throws it out from the trough, at a considerable elevation. These wheels are used, for draining ponds, marshes, &c., and are turned by wind-mills, or any other power. If their movement is slow, they simply lift the water, and cause it to overflow, at llie end of the trough. But, if thev 164 COMBINING FLEXIBLE FIBRES. revolve with much velocity, they are capable of throw¬ ing the water to a still higher level. Works of Reference.—Robison’s Mechanical Philosophy, a.r- iklus, Theory of Rivers, Water Works,%ic.\ — Gregory’s Mechan¬ ics, vol. i.; —Young’s Natural Philosophy, vol. i.;—Hydraulia,or an Account of the Water Worksof London, 8vo. 1885 ; —Bossgt, Traite Theoretique et Experimental d' Hydrodynamique, 1771, &c.;—Du liuAT Traite d' Hydraulique, et Pyrodynamique, 1786, &c.; — Ven¬ turi, Recherches Experiinentales sur les Fluides, 1797;— Rees’ Cyclopedia, article Water; —Edinburgh Encyclopedia, article Hydro¬ dynamics; —and the Hydraulic Works ofMARioxTE, Guglieemi- Ni, Michalotti, D. and J. Bernoulli, D’ Alembert, Fon¬ tana, M. Young, Prony, Vince, Juan, Eytelwein, &c. CHAPTER XVIII. ARTS OF COMBINING FLEXIBLE FIBRES. Theory of Twisting, Rope Jlaking, Hemp Spinning. Cotton JSIun- nfacture. Elementary Inventions, Batting, Carding, Drawing, Rov¬ ing, Spinning, Mule Spinning, Warping, Dressing, Weaving, Twil¬ ling, Double Weaving, Cross Weaving, Lace, Carpeting, Tapestry, Velvets, Linens. Woollens, Felting. Paper Making. Book¬ binding. Theory of Twisting .—The strengtli of cordage, which is employed in uniting bodies, and the utility of flexible textures, which serve for furniture, or for clothing, de¬ pend, principally, upon the friction, or lateral adhesion, produced by the twisting and intermixture of their constit¬ uent fibres. A twisting cord is not so strong as the fibres which compose it, supposing the fibres and cord to be of the same length. The object of twisting is, to connect suc¬ cessive numbers of short fibres, in such a manner, that, besides the mutual pressure which their own elasticity causes them to exert, any additional force, applied in the direction of the length of the aggregate, may tend to bring their parts into closer contact, and augment their adhesion vO each other. The simple art of tying a knot, and the ROPE-MAKING. 165 more complicated processes of spinning, rope-making, weaving, and felting, derive most of their utility from this principle. By considering the effect of a force, which-is counter¬ acted by other forces, acting obliquely, it will be seen, that the operation of twisting has a useful effect, in bind¬ ing the parts of a rope, or thread, together; and also, that it has an inconvenience, in causing the strength of the fibres to act with a mechanical disadvantage. 'I’lie great¬ er is the obliquity of the fibres, the greater will be their adhesion to each other, but the greater, also, will be their immediate strain, or tension, when a force acts upon them, in the direction of the whole cord. From this, it follows, that, after employing as much obliquity, and as much ten¬ sion, as is sufficient to connect the fibres firmly together, all that is superfluously added tends to weaken the cord, by overpowering the primitive cohesion of the fibres, in the direction of their length. The mechanism of simple spinning is easily understood. Care is taken, where the hand is employed, to intermix the fibres sufficiently, and to engage their extremities, as much as possible, in the centre ; for, it is obvious, that, if any fibre were wholly external to the rest, it could not be retained in the yarn. In general, however, the materials are, previously, in such a state of intermixture, as to ren¬ der this precaution unnecessary. Rope Making .—A single thread of yarn, consisting of fibres twisted together, has a tendency to untwist itself, the external parts being strained, by extension, and the internal parts, by compression ; so that the elasticity of all the parts resists, and tends to restore the thread to its natural state. But, if two such threads, similarly twisted, are retained in contact, at a given point of the circumfer¬ ence of each, this point is rendered stationary, by the opposition of the equal forces, acting in contrary direc¬ tions, and becomes the centre, round which both threads are carried, by the forces which remain ; so that they con¬ tinue to twist round each other, till the new combination causes a tension, capable of counterbalancing the remain¬ ing tension of the original threads. Three, four, or more. 166 COMBINING FLEXIBLE FIBRES, threads may be united, nearly in the same manner. A strand, as it is called by rope-makers, consists of a con¬ siderable number of yarns, thus twisted together, gener¬ ally from sixteen to twenty-five ; a halser consists of three strands ; a shroud, of four ; and a cable, of three halsers, or shrouds. Shroud-laid cordage has the disadvantage of being hollow in the centre, or else of requiring a great change of form in the strands, to fill up the vacuity ; so that, in undergoing this change, the cordage stretches, and is unequally strained. The relative position, and the comparative tension, of all the fibres, in these complicated combinations, are not very easily determined by calcula¬ tion ; but, it is found, by experience, to be most advan¬ tageous for the strength of ropes, to twist the strands, when they are to be compounded, in such a direction, as to untwist the yarns, of which they are formed ; that is, to increase the twist of the strands themselves ; and, proba¬ bly, the greatest strength is obtained, when the ultimate obliquity of the constituent fibres is least, and the most equable.* A very strong rope may, also, be made, by twisting five or six strands round a seventh, as an axis. In this case, the central strand, or heart, is found, after much use, to be chafed to oakum. Such ropes are, however, considered unfit for rigging, or for any use, in which they are liable to be frequently bent. Ropes are most commonly made of hemp ; but various other vegetables are occasionally employed. The Chi¬ nese even use woody fibres ; and the barks of trees fur¬ nish cordage to other nations. In spinning the yarn, in the piocess of rope-making, the hemp is fastened round the waist of the workman ; one end of it is attached to a wheel, turned by an assistant, and the spinner, walking backwards, draws out the fibres with his hands. When one length of the walk has been spun, it is immediately reeled, to prevent its untwisting. The machines, employ¬ ed in continuing the process of rope-making, are mostly cf simple construction ; but both skill and attention are * Young’s Natural Philosophy, vol. i. Lect. xvi. HEMP-SPINNING.—COTTON MANUFACTURE. 1G7 required, in applying them, so as to produce an equable texture, in every part of the rope. The tendency of two strands to twist, in consequence of the tension, arising from the original twist of the yarns, is not sufficient to produce an equilibrium, because of the friction and rigidity to be overcome. Hence, it is necessary to employ force, to assist this tendency, and the strands, or ropes, will after¬ wards retain, spontaneously, the form which has thus been given them. The largest ropes, even, require external force, in order to make them twist at all. The constituent ropes of a common cable, when sepa rate, are stronger than the cable, in the proportion of about four to three ; and a rope, worked up from yarns, one hun¬ dred and eighty yards in length, to one hundred and thirty- five yards, has been found to be stronger, than when reduc¬ ed to one hundred and twenty yards, in the ratio of six to five. The difference is owing, partly, to the obliquity of the fibres, and, partly, to the unequal tension, produced by twisting.* Hemp Spinning .—The desideratum of spinning hemp, by machinery, has been attained by Mr. Treadwell, in his machines for tliat purpose, now at work, at the Charles¬ town Navy Yard, and elsewhere. By this invention, the hemp is drawai out to the requisite size, by a long series of teeth, fixed upon a revolving belt, and afterwards twist¬ ed, by tlie revolutions of the machine. Tlie equality, or uniform size, of the yarn, is ensured, by a roller, or small wheel, which rests upon the part just twisted, and which rises, or is pushed up, if the twist becomes loo large, and moves a comb, which immediately falls, and intercepts the superfluous part of the fibres. On the other hand, if the twist becomes too small, the roller descends, and, in so doing, increases the rapidity of the machine, and causes it to supply the hemp faster. COTTON MANUFACTURE. When the fibres of cotton, wool, or flax, are Intended to be woven, they are reduced to fine threads, of uniform * Young’s Natural Philosophy, vol. i. I.ect. xvi. 168 COMBINING FLEXIBLE FIBRES. Size, by the well-known process of spinning. Previous¬ ly to the middle ot the last century, this process was per¬ formed by hand, with the aid of the common spinning- wheel. Locks of cotton, or wool, previously carded, were attached to a rapidly-revolving spindle, driven by a large wheel, and were stretched or drawn out by the hand, at the same time that they were twisted by the spindle, upon which they were afterwards wound. Flax, the fibres of which are longer, and more parallel, was loosely wound upon a distafi:’, from which the fibres were selected, and drawn out by the thumb and finger, and, at the same time, were twisted by flyers, and wound upon a bobbin, which revolved with a velocity, somewhat less than that of the flyers. The manufacture of flexible stuffs, by means of machin¬ ery, operating on a large scale, is an invention of the last century. Although of recent date, it has given birth to some of the most elaborate and wonderful combinations of mechanism, and already constitutes, especially in Eng¬ land, and in this country, an important source of national wealth and prosperity. Elementary Inventions .—The character of the machin¬ ery which has been applied to the manufacture of cotton, at different times, has been various. There are, howev¬ er, several leading inventions, upon which most of the essential processes are founded, and which have given to their authors a greater share of celebrity than the rest. These are, 1. The spinning-jenny. This machine was invented by James Hargreaves,* in 1767, and, in its simplest form, resembled a number of spindles, turned by a common wheel, or cylinder, which was worked by hand. It stretched out the threads, as in common spin¬ ning of carded cotton. 2. The water spinning-frame^ invented by Richard Arkwright, in 1769. The essen¬ tial, and most important, feature in this invention con¬ sists in the drawing out, or elongating, of the cotton, by causing it to pass between successive pairs of rollers, which revolve, with different velocities, and which act as * Mr. Guest, in a late work, attributes the invention, both of the jen¬ ny, and water spinning-frame, to Thomas Highs, of Leigh, England. BATTING. 169 substitutes for the finger and thumb, as applied in common spinning. These rollers are combined with the spindle and flyers of the common flax wheel. 3. The mule. This was invented by Samuel Crompton, in 1779. It combines the principles of the two preceding inventions, and produces finer yarn, than that which is spun in either of the other machines. It has now nearly superseded the jenny. 4. The power-loom for weaving, by water or steam power, which was introduced about the end of the eighteenth century, and has received various modifica¬ tions. The foregoing fundamental machines are used in the same, or difl’erent establishments, and for different pur¬ poses. But, besides these, various auxiliary machines are necessary, to perform intermediate operations, and to pre¬ pare the material, as it passes from one stage of the man¬ ufacture to another. The number of these machines, and the changes, and improvements, which have been made in their construction, from time to time, render it impossible to convey, in a work like the present, any accurate idea of their formation, in detail. A brief view, however, of the offices which they severally perform, may be taken, by following the raw material, through tl)e principal changes which it undergoes, in a modern cotton-factory, founded and improved upon the general principles of Arkwright. Batting .—The cotton, after having been cleared from its seeds, at the plantation, by the operation of ginningy described on page 111, Vol. I., is compressed into bags, for exportation, and arrives at the factory, in a dense and matted mass. The first operation to which it is submitted has, for its object, to disentangle the fibres, and restore the cotton to a light, open, and uniform, state. For this pur¬ pose, after being weighed out, it is submitted to the ope¬ ration of a machine, called a picker, or of another, de¬ nominated a butter. In some of these machines, it is subjected to the action of a series of pins ; in others, to a sort of blunt knives, revolving with great rapidity ; the effect of which is, to beat up and separate the fibres, to disengage their unequal adhesions, and to reduce the whola to a very light, uniform, flocculent, mass. . XII. 170 C0MB1^’I^^G FLEXIBLE FIBRES. Carding. —The cotton next passes to the carding-ma- chines, of which, when there are two, the first is called the breaker, and the second, the finisher. In this opera¬ tion, the cotton is carried over the surface of a revolving cylinder, which is covered with card-teeth of wire, and which passes in contact with an arch, or part of a con¬ cave cylinder, similarly covered with teeth. From this cylinder, it is taken oft' by another, called the doffing cyl¬ inder, which revolves in an opposite direction ; and from this, it is again removed, by the rapid vibrating movement of a transverse comb, otherwise called the doffiing-plate, moved by cranks. It then exists in the state of a flat, uniform, fleece, or lap, which, after passing the breaker, undergoes the process of plying, or doubling, by causing it to perform a certain number of revolutions upon a cyl¬ inder, or a perpetual cloth. It is then carded a second time, by the finisher, and the fleece, after being taken oft' from this machine, is drawn by rollers, through a hollow cone, or trumpet mouth, which contracts it to a narrow band, or sliver, and leaves it coiled up in a tin can, ready for the next operation. The process of carding serves to equalize the substance of the cotton, and to lay its fibres somewhat in a more parallel direction. Drawing. —The slivers of cotton are next elongated, by the process of drawing. This operation is the ground¬ work, or principle, of Arkwright’s invention, and is used in the roving, and spinning, as well as in the drawings frame. It is an imitation of what is done by the finger and thumb, in spinning by band, and is performed, by means of two pairs of rollers. The upper roller, of the first pair, is covered with leather, which, being an elastic substance, is pressed, by means of a spring, or weight. The lower roller, made of metal, is fluted, in order to keep a firm hold of the fibres of cotton. Another similar pair of rollers are placed near those which have been de¬ scribed. The second pair, moving with a greater veloc¬ ity, pull out the fibres of cotton from the first pair of rol¬ lers. If the surface of the last pair move at twice, or thrice, the velocity of the first pair, the cotton will be drawn twice, or thrice, finer than it was before. This ROVING. 171 relative velocity is called the draught of the machine. This mechanism being understood, it will be easy to con¬ ceive the nature of the operation of the drawing-frame. Several of the narrow ribands, or slivers, from the cards, (sometimes termed card-ends^) by being passed through a system of rollers, are thereby reduced in size. By means of a detached, single pair of rollers, the several re¬ duced ribands are plied, or united into one sliver. The operations of drawing and plying serve to equalize, still further, the body of cotton, and to bring its fibres more into a lonsritudinal direction. These slivers are O again combined, and drawn out, so that one sliver of the finished drawing contains many plies of card-ends. Hith¬ erto, the eotton has acquired no twist, but is received into movable tin cans, or canisters, similar to those used for receiving the cotton from the cards. Roving .— The operation of roving communicates the first twist to the cotton. It is performed by a machine, called the roving-frame, or double-speeder. The tin cans, containing the slivers of cotton, are placed upon this ma¬ chine, and are made to revolve, slowly, about tlieir axes, so as to produce a slight degree of twisting. The slivers then pass again, through several pairs of rollers, moving with difierent speeds, and are thus still further attenuated, by drawing, 'i’hey are then slightly spun, by the revolu¬ tion of flyers, and are wound upon the bobbins of the spindles, in the form of a loose, soft, imperfect, thread, denominated the roving. 'J’he mechanism of the double speeder is complicated, and interesting, and great ingenuity has been displayed, in overcoming tiie difiiculties of its construction. In order that the yarn, or roving, may be wound uj)on the bobbins, in even, cylindrical, layers, it is necessary, that the spindle- rail, or horizontal bar, which supports the spindles, should continually rise and fall, with a slow alternate motion. This is effected by heart-wheels, or cams, in the interior of the machine. Again, since the collective size of the bobbin is augmented, by the addition of each layer of roving, it is obvious, that, if the axis of the bobbin re volved, always, with the same velocity, the thread of rov 172 COMBINING FLEXIBLE FIBRES. ing would be broken, in consequence of being wound up too fast. To prevent this accident, the velocity of the spindles, and, likewise, the motion of the spindle-rail, is obliged gradually to diminish, from the beginning to the end of an operation. This diminution of speed is effect¬ ed, by transmitting the motion, both to the spindle-rail, and to the bobbins, through two opposite cones, one of which drives the other with a band, the band being made to pass, slowly, from one end to the other of the cones, and thus continually to alter their relative speed, and cause a uniform retardation of the velocity of the moving parts.* As the roving is not strong enough to bear any violence, the spindles, which support the bobbins, are geared to each other, so as to prevent any deviation from the proper velocity. A more simple form of the roving-frame has been in¬ vented,! in which the gearing is dispensed with, as well as the pair of cones, which regulates the motion of the bobbins. In this machine, the bobbins are not turned by the rotation of their axes, but by friction, applied to their surface, by small wooden cylinders which revolve in con¬ tact with them. In this way, the velocity of the surface of the bobbin will always be the same, whatever may be its growth, from the accumulation of roving, so that the winding goes on, at an equable rate. To prevent the rov¬ ing from being stretched, or broken, in its passage from the drawing rollers to the bobbins, it is made to pass through a tube, which has a rapid rotation, and which twdsts it, in the middle, into a cord of some firmness. It is again untwisted, as fast as it escapes from the tube, and is wound upon the bobbins, in the form of a dense, even, cord, but without any twist. Spinning .—The bobbins, which contain the cotton, in a state of roving, are next transferred to the spinning- frame. It is here once more drawn out by rollers, and twisted by flyers, so that the spinning is little more than * Instead of band c.);.os, an ingenious mode of using geared cones, now introduced in s” .eral American factories, has already been de¬ scribed, page 60. t By Mr. Danforth, of Massachusetts. MULE-SPINNING. 173 a repetition of the process gone through, in making the roving, except that the cotton is now twisted into a strong thread, and cannot any longer be extended, by drawing. The flyers of the spinning-frame are driven by bands, which receive their motion, in some cases, from a hori¬ zontal fly-wheel, and, in others, from a longitudinal cylin¬ der.* As the thread is sufficiently strong not to break with a slight force, the resistance of the bobbins, by fric¬ tion, is relied on to wind it up, instead of having the spin¬ dles geared together, and turned with an exact velocity, as they are in the common double-speeder. In the spin¬ ning frame, the heart-motion is retained, to regulate the rise and fall of the rail ; and, in those frames which spin the woof, or filling, it is applied, by a progressive sort of cone, the section of which is heart-shaped, and which acts, remotely, to distribute the thread, in conical layers, upon the bobbins, that it may unwind the more easily, when placed, afterwards, in the shuttle. jMule Spinning .—Tiie processes of water-spinning, already described, are adequate to produce yarns, of suf¬ ficient fineness for ordinary fabrics. But, for producing threads of the finest kind, another process is necessary, which is called stretching, and which is analogous to that which is performed, witli carded cotton, upon a commr'n spinning-uheel. In this operation, portions of yarn, s'””- eral yards long, are forcibly stretched, in the direction their length. It differs, therefore, from the operation of drawing, in which a few inches, only, are extended at ^ time. The stretching is performed, with a view to elon¬ gate and reduce those places in the yarn, which have v greater diameter, and are less twisted, than the other parts so that the size and twist of the thread may become uni¬ form throughout. To eflect the process of stretching, the spindles are mounted upon a carriage, which is moved, back and forwards, across the floor ; receding, when the threads are to be stretched, and returning, when they are to be wound up. The yarn, produced by mule-spinning, is more perfect than any other, and is employed in the * The latter method, wliich had gone Into disuse, is beginning to be revived, and to be considered most advantageous. 15* 174 COMBINING FLEXIBLE FIBRES. fabrication of the finest articles. The sewing-thread, spun by mules, is a combination of two, four, or six, con¬ stituent threads, or plies. Threads have been produced, of such fineness, that a pound of cotton has been calculat¬ ed to reach one hundred and sixty-seven miles. Warping .—The first step, preparatory to weaving, is to form a loarp., which consists of parallel threads, con¬ tinued through the whole length of the intended piece, and sufficient, in number, to constitute its breadth. It was, formerly, the practice to attach the threads to as many pins, and to draw them out, to the required length. But, as this method required too much room, a warping ma¬ chine was subsequently used, in which the mass of threads, intended to constitute a warp, was wound in a spiral course, upon a large revolving frame, which rose and fell, so as to produce the spiral distribution. These methods are now superseded, in this country, by Moody’s warping-machine,* an ingenious piece of mechanism, in which a number of bobbins, equal to one eighth part of the number of threads in the intended warp, are arranged upon the surface of a concave frame. The threads pass through a reed, which separates the alternate threads, as they are to be kept in the loom ; after which, they are wound upon a beam, with rods interposed at the end, to preserve the separation. But the most interest¬ ing part of the mechanism is a contrivance for stopping the machine, if a single thread of the warp breaks. To effect this object, a small steel weight, or flattened wire, is suspended, by a hook, from each thread, so that it fails, if the thread is broken. Beneath the row of weights, a cylinder revolves, furnished with several projecting ledges, extending its whole length, parallel to the axis. When one of the weights falls, by the breaking of its thread, it intercepts one of the ledges, and causes the cylinder to exert its force upon an elbow, or toggle-joint, which dis¬ engages a cluich, and stops the machine. After the thread is tied, and the weight raised, the machine proceeds. * Mr. Paul Moody, formerly of Waltham, and now of Lowell, is the inventor of this machine ; likewise of the spinning-frame, which winds the woof in conical layers ; and of great improvements in the roving frame, the dressing-frame, &c. DRt:sSIi\G.-WKAVING. 175 Dressing .—As the threads, which constitute the warp, are liable to much friction, in the process of weaving, they are subjected to an operation, called dressing, the object of which is, to increase their strength and smoothness, by agglutinating their fibres together. To this end, they are pressed between rollers, impregnated with mucilage, made of starch, or some gelatinous material, and, immediately afterwards, brought in contact with brushes, which pass repeatedly over them, so as to lay down the fibres in one direction, and remove the superfluous mucilage from them. They are then dried, by a series of revolving fans, or by steam-cylinders, and are ready for the loom. Weaving .—Woven textures derive their strength from the same force of lateral adhesion, which retains the twis¬ ted fibres of each thread in their situations. The man¬ ner, in which these textures are formed, is readily under¬ stood. On inspecting a piece of plain cloth, it is found to consist of two distinct sets of threads, running perpen¬ dicularly to each other. Of these, the longitudinal threads constitute the rcarp, while the transverse threads are called the tcor^, iveft., or Jilling, and consist of a single thread, passing backwards and forwards. In weaving with the common loont, the warp is wound upon a cylindrical beam, or roller. From this, the threads pass through a har¬ ness., composed of movable parts, called the heddles, of which there are two or more, consisting of a series of vertical strings, connected to frames, and having loops, through which the warp passes. When the heddles con¬ sist of more than one set of strings, the sets are called leaves. Each of these heddles receives its portion of the alternate threads of the warp; so that, when they are moved, reciprocally, up and down, the relative position of the alternate threads of the warp is reversed. Each time that the warp is opened, by the separating of its al¬ ternate threads, a shuttle, containing the woof, is thrown across it, and the thread of a woof is immediately driven into its place, by a frame, called a lay, furnished with thin reeds, or wires, placed among the warp, like the teeth of a comb. The woven piece, as fast as it is completed, is wound up on a second beam, opposite to the first. 176. COMBINING FLEXIBLE FIBEE*, Power looms, driven by water, or steam, aithoogh a late invention, are now universally introduced into manu¬ factories of cotton and woollens. As the motions of the loom are, chiefly, of a reciprocating kind, they are produ¬ ced, in some looms, by the agency of cranks, and in oth¬ ers, by cams, or wipers, acting upon weights, or springs* Twilling .—In the mode of plain weaving, last describ¬ ed, it will be observed, that every thread of the warp crosses at every thread of the woof, and vice versa. In articles, which are twilled, or tweeled, this is not the case; for, in this manufacture, only the third, fourth, fifth, sixth, &c., threads cross each other, to form the texture. In the coarsest kinds, every third thread is crossed ; but, in finer fabrics, the intervals are less frequent, and, in some very fine twilled silks, the crossing does not take place, till the sixteenth interval. In Fig 178, is shown a magnified Fig. 178. section of a piece of plain cloth, in which the woof passes, alternately, over and under every thread of the warp. In Fig. 79, is a piece of twilled cloth, in which the thread Fig. 179. OOOO-ioOOO^-XXXO'-^^ of the woof passes, alternately, over four, and under one, of the threads of the warp, and performs the reverse, in its return. To produce this efiect, a number of leaves of heddles are required, equal to the number of threads contained in the interval, between each intersection, in¬ clusive. By the separate movements of these, the warp is placed in the requisite positon, before each stroke of the shuttle. A loom, invented in this country, by Mr. Batchelder, of Lowell, has been applied to the weaving of twilled goods, by water-power. Twilled fabrics are thicker than plain ones, when of the' same fineness, and more flexible, when of the same thick¬ ness. They are also more suceptible of ornamental va- DOUBLE-WEAVING.-CROSS-WEAVING. 177 nations. .leans, dimities, serges, &c.,are specimens of this kind of texture. Double JVeaving .—In this species of weaving, the fa¬ bric is composed of two webs, each of which consists of a separate warp, and a separate woof. The two, however, are interwoven, at intervals, so as to produce various fig¬ ures. The junction of the two webs is formed, by pass¬ ing them, at intervals, through each other ; so that each particular part of both is sometimes above, and sometimes below. It follows, that, when different colors are employ¬ ed, as in carpeting, the figure is the same, on both sides, but the color is reversed. A section of double cloth is shown in Fig. 180. The weaving of double cloths is commonly performed, by a complicated machine, called a draio-loom, in which the weaver, aided by an assistant, or by machinery, has the command of each particular thread, by its number, lie works by a pattern, in which the figure before him is traced, in squares, agreeably to which the threads to be moved are selected, and raised, before each insertion of the woof. Kidderminster carpets, and Marseilles quilts, are specimens of this mode of weaving. Cross JVeaving .—This method is used, to produce the lightest fabrics, such as gauze, netting, catgut, &c. In the kinds of weaving which have been previously described, the threads of the warp always remain parallel to each oth¬ er, or without crossing. But, in gauze-weaving, the two threads of warp, which pass between the same splits of the reed, are crossed over each other, and partially twisted like a cord, at every stroke of the loom. They are, however, twisted to the right and left, alternately, and each shot, or insertion of the woof, preserves the twist which the warp has received. A great variety of fanciful textures are pro- 178 ' COMBINING FLEXIBLE FIBRES. duced, by variations of the same general plan. Fig. 181 , represents the cross-weaving, used in common gauze. Fig. 181. Lace .—Lace is a complicated, ornamental, fabric, formed of fine threads of linen, cotton, or silk. It consists of a net-work of small meshes, the most common form of which is hexagonal. In perfect thread-lace, four sides of the hexagon consist of threads which are twisted, while, in the remaining two, they are simply crossed. Lace has been commonly made upon a cushion, or pillow, by the slow labor of artists. A piece of stiff parchment is stretch¬ ed upon the cushion, having holes pricked through it, in which pins are inserted. The threads, previously wound upon small bobbins, are woven round the pins, and twist¬ ed, in various ways, by the hands, so as to form the requir¬ ed pattern. The expensiveness of the different kinds of lace is proportionate to the tediousness of the operation. Some of the more simple fabrics are executed with rap¬ idity, while others, in which the sides of the meshes are plaited, as in the Brussels lace, and that made at Valen¬ ciennes, are difficult, and bear a much greater price. The cheaper kinds of lace have long been made by machinery ; and, recently, the invention of Mr. Heath- coat’s lace-machine has effected the fabrication of the more difficult, or twisted lace, with precision and des patch. This machine is exceedingly complicated and ingenious, and is now in operation in this country, and in France, as well as in England. Carpeting .—Carpets are thick textures, composed, wholly or partly, of wool, and wrought by several dissimi¬ lar methods. The simplest mode is that used in weav¬ ing the Venetian carpets, which is a plain texture, com¬ posed of a striped woollen warp, on a thick woof of linen thread. Kidderminster carpeting is composed by two woollen webs, which intersect each other, in such a manner, as to produce definite figures. Brussels carpet TAPESTRV.-VELVETS. 179 ing has a basis, composed of a warp and woof, of strong linen thread. But, to every two threads of linen, in the warp, there is added a parcel of about ten threads of woollen, of different colors. The linen thread never appears on the upper surface ; but parts of the woollen threads are, from time to time, drawn up in loops, so as to constitute ornamental figures, the proper color being, each time, selected from the parcel to which it belongs. A sufficient number of these loops is raised, to produce a uniform surface, as seen in Fig. 182 ; and to render them equal, each row passes over a wire, which is subsequent¬ ly withdrawn. In some cases, the loops are cut through with the end of the wire, which is sharpened for the pur¬ pose, so as to cut off the threads, as it passes out. In forming the figure, the weaver is guided by a pattern, which is drawn in squares, upon a paper. Turkey car¬ pets appear to be fabricated upon the same general prin¬ ciples, as the Brussels, except that the texture is all wool¬ len, and the loops larger, and always cut. Tapesiry .—The name of tapestry is given to certain delicate and complicated fabrics, in which the forms and colors of natural objects are produced, with such accura¬ cy, as to resemble fine paintings. The mode of texture used, to produce this effect, is, in many respects, analo¬ gous to that by which the finer carpetings are made. The minuteness, however, of the constituent parts, causes the sight of the texture to be lost, in the general effect of the piece. The fabrication of tapestry is slow, intricate, and very expensive. The most celebrated manufactory is that established by the family of Gobelins, and kept up by their successors, at Paris. Velvets .—The fine soft nap, by which velvet is cov¬ ered, is produced by a method, not unlike that which is used in carpeting and tapestry. It is formed of a part 180 COMBINING FLEXIBLE FIBRES. of the threads of the warp, which the workman puts, in' loops, on a long, channelled wire. Before the wire is withdrawn, the row of loops is cut open, by a sharp steel instrument which is drawn along the channel of the wire. Various other fabrics of silk, cotton, and wool, such as thicksets, plushes, corduroys, velveteens, &.C., are cut in a similar manner. Cotton counterpanes are woven with two shuttles, one containing a much coarser woof than the other. The coarser of the threads is picked up, at intervals, with an iron pin, which is hooked at the point, thus forming knobs, which are made to constitute regular figures. In cotton fabrics, the web, when taken from the loom, IS covered with an irregular nap, or down, formed by the projecting ends of the fibres. This is removed, in the finest articles, by burning it off, the heat being so man¬ aged, as not to injure the texture of the cloth. The oper¬ ation is performed, by drawing the web, very rapidly, over an iron cylinder which is kept constantly red hot, by a fire within it. The velocity of the cloth prevents it from burning, while the loose filaments, which constitute the nap, are singed off. The flame of coal-gas has, of late, been applied to the same purpose. Linens .—This name belongs to fabrics, which are man¬ ufactured from flax ; but those made of hemp are similar in their properties, except in fineness. Tlie length and comparative rigidity, of the fibres of flax, present diffi¬ culties, in the way of spinning it, by the machinery which is used for cotton and wool. It cannot be prepared, by carding, as these other substances are, and the rollers are capable of drawing it but very imperfectly. The subject of spinning flax, by machinery, has attrncted much attention, and the Emperor Napoleon, at one time, oftered a reward of a million of francs, to the inventor of the best machine, for this purpose. Various individuals, both in this country, and in Europe, have succeeded in constructing machines, w'hich spin coarse threads of linen, sufficiently well, and with great rapidity. But the manu¬ facture of fine threads, such as those used for cambrics and^ lace, continues to be performed, by hand, upon the ancient spinning-wheel. WOOLLENS. 181 Linen was manufactured by the Egyptians, probably, one thousand five hundred years before Christ. Some of it was of exceeding fineness. Vast quantities, in the form of mummy-cloths, still remain. WOOLLENS. The fibres of wool, being contorted and elastic, are drawn out and spun, by machinery, in some respects sim¬ ilar to that used for cotton, but difiering in various partic¬ ulars. Independently of the quality of fineness, there are two sorts of wool, which afford the basis of different fabrics, the long wool, and the short. Long wool is that, in which the fibres are rendered parallel, by the process of combing. It is also known by the name of worstedy and is the material, of which camlets, bombazines, &.C., are made. Short wool is prepared, by carding, like cot¬ ton^ and is used, in different degrees of fineness, for broad¬ cloths, flannels, and a multitude of other fabrics. This w^ool, when carded, is formed into small, cylindrical rolls, which are joined together, and stretched, and spun, by a slubbing, or roving, machine, and a jenny, or mule ; in both of which, the spindles are mounted on a carriage, which passes backwards and forwards, so as to stretch the material, at the same time that it is twisted. On ac¬ count of the roughness of the fibres, it is necessary to cover them witJi oil, or grease, to enable them to move freely upon each other, during the spinning and weaving. After the cloth is woven, the oily matter is removed, by scouring, in order to restore the roughness to the fibres, preparatory to the subsequent operation of fulling. In articles which are made of long wool, the texture is complete, when the stuff issues from the loom. The pieces are subsequently dyed, and a gloss is communica¬ ted to them, by pressing them between heated metallic surfaces. But, in cloths made of short W'ool, the weav¬ ing cannot be said to have completed the texture. When the web is taken from the loom, it is too loose and open, and, consequently, requires to be submitted to another op¬ eration, called fulling. This is performed by a fulling- mill, in which the cloth is Immersed in water, and subject- n. 16 XII. 182 COMBINING FLEXIBLE FIBRES. ed to repealed compressions, by the action of large beaters, formed of wood, which repeatedly change the position of the cloth, and cause the fibres to felt, and combine more closely together. By this process, the cloth is reduced in its dimensions, and the beauty and stability of the tex¬ ture are greatly improved. The tendency to become thickened, by fulling, is peculiar to wool and hair, and does not exist in the fibres of cotton, or flax. It depends on a certain roughness of these animal fibres, which per¬ mits motion, in one direction, while it retards it, in anoth¬ er. It thus promotes entanglements of the fibres, which serve to shorten and thicken the woven fabric. Before the cloth is sent to the fulling-mill, it is necessary to cleanse it from all the unctuous matter, which was ap¬ plied, to prepare the fibres for spinning. The nap, or downy surface, of broadcloths, is raised, by a process, which, while it improves the beauty, tends somewhat to diminish the strength, of the texture. It is produced, by carding the cloth, with a species of burrs, the fruit of the common teazle, {Dipsaciis fullonurn,) which is cultivated for the purpose. This operation ex¬ tricates a part of the fibres, and lays them in a parallel direction. The nap, composed of these fibres, is then cut off, to an even surface, by the process of shearing. This is performed in various ways; but in one of the most common methods, a large spiral blade revolves, rapidly, in contact with another blade, while the cloth is stretched over a bed, or support, just near enough for the projecting filaments to be cut oti', at a uniform length, while the main texture remains uninjured. FELTING. The texture of modern hats, which are made of fur and wool, depends upon the process o(felting, which is sim¬ ilar to that of fulling, already described. The fibres of these substances are rough, in one direction only ; a cir- (urnstance which may be perceived, by passing a hair through the figures, in opposite directions. This rough¬ ness allows the fibres to glide among each other, so that, when the mass is agitated, the anterior extremities slide PAPER-MAKING. 183 forward, in advance of the body, or posterior half of the hair, and serve to entangle, and contract, the whole mass together. The materials, commonly used for hat-making, are the furs of the beaver, seal, rabbit, and other animals, and the wool of sheep. The furs of most animals are mixed with a longer kind of thin hair, which is obliged to he first pulled out, after which, the fur is cut off, with a knife. The materials to be felted are intimately mixed together, by the operation of hotoing, which depends on the vibrations of an elastic string ; the rapid alternations of its motion being peculiarly well adapted to remove all irregular knots and adhesions, among the fibres, and to dispose them in a very light and uniform arrangement. This texture, when pressed under cloths and leather, readily unites into a mass of some firmness. This mass is dipped into a liquor, containing a little sulphuric acid ; and, when intended to form a hat, it is first moulded into ,a large conical figure, and this is afterwards reduced in its dimensions, by working it, for several hours, with the hands. It is then formed into a flat surface, with several concentric folds, wliich are still further compacted, in or¬ der to make the brim, and the circular part of the crown, and forced on a block, which serves as a mould, for the cylindrical part. The nap, or outer portion of the fur, is raised with a fine wire brush, and the hat is subsequent¬ ly dyed and stifiened, on the inside, with glue. An attempt has been made, and, at one time, excited considerable exj)ectation in England, to form woollen cloths by the process of felting, without spinning or weav¬ ing. Perfect imitations of various cloths, were produced ; hut they were found deficient in the firmness and dura¬ bility, which belongs to woven fabrics. PAPER-MAKING. The combination of flexible fibres, by which papdr is produced, depends on the minute subdivision of the fibres, and their subsequent cohesion. Linen and cotton rags are the common material, of which paper is made ; but hemp, and some other fibrous substances, are used for the coarser kinds. These materials, after being washed, 184 COMBINING FLEXIBLE FIBRES. are subjected to the action of a revolving cylinder, the surface of which is furnished with a number of sharp teeth, or cutters, which are so placed, as to act against other cut¬ ters, fixed underneath the cylinder. The rags are kept immersed in water, and continually exposed to the action of the cutters, for a number of hours, till they are minute¬ ly divided, and reduced to a thin pulp. During this pro¬ cess, a quantity of chloride of lime is mixed with the rags, the efi’ect of which is to bleach them, by discharging the coloring matter, with which any part of them may be dyed, or otherwise impregnated. Before the discovery of this mode of bleaching, it was necessary to assort the rags, and select only those which were white, to consti¬ tute white paper. If, however, the bleaching process be carried too far, it injures the texture of the paper, by cor¬ roding and weakening the fibres. The pulp, composed of the fibrous particles, mixed with water, is transferred to a large vat, and is ready to be made into paper. The workman is provided with a mouldy which is a square frame, with a fine wire bottom, resem¬ bling a sieve, of the size of the intended sheet. With this mould, he dips up a portion of the thin pulp, and holds it in a horizontal direction. The water runs out through the interstices of the wires, and leaves a coating of fibrous particles, in the form of a sheet, upon the bottom of the mould. The sheets, thus formed, are subjected to pres¬ sure, first between felts, or woollen cloths, and afterwards alone. They are then sized, by dipping them in a thin so¬ lution of gelatin, or glue, obtained from the shreds and par¬ ings of animal skins. The use of the size is to increase the strength of the paper, and, by filling its interstices, to prevent the ink from spreading among the fibres, by capillary attraction. In blotting paper, the usual sizing is omitted. The paper, after being dried, is pressed, examined, selected, and made into quires and reams. Hot-pressed paper is rendered glossy, by pressing it between hot plates of polished metal. Paper is also manufactured by machinery ; and one of the most ingenious methods is that invented by the BOOKBINDING. 185 Messrs. Fourdrinier. In this arrangement, instead of moulds, the pulp is received in a continual stream, upon the surface of an endless web of brass wire, which extends round two revolving cylinders, and is kept in continual motion forwards, at the same time that it has a tremulous, or vibrating, motion. The pulp is thus made to form a long, continual sheet, which is wiped off from the wire web, by a revolving cylinder, covered with flannel, and, after being compressed between other cylinders, is finally wound into a coil, upon a reel, prepared for the purpose. Another machine for making paper, consists of a hori¬ zontal revolving cylinder of wire web, which is immersed in the vat, to the depth of more than half its diameter. The water penetrates into this cylinder, being strained through the wire web, at the same time depositing a coat of fibrous particles on the outside of the cylinder, which constitute paper. The strained water flows off, through the hollow axis of the cylinder, and the paper is wound off, from the part of the cylinder which is above water, in the form of a continued sheet. As a specimen of the rapidity with which paper may now be manufactured, Mr. Passey, of Birmingham, has in his possession, a document, the material of which was in a state of rags, was made into paper, dried, and printed, in the space of five minutes, in the presence of many witnesses. Bookbindingy according to the present mode, is per¬ formed in the following manner. The sheets are first folded into a certain number of leaves, according to the form in which the book is to appear; viz., two leaves for folios, four for quartos, eight for octavos, twelve for duo¬ decimos, Slc. I'liis is done with a slip of ivory or box¬ wood, called a folding-stick. In the arrangement of the sheets, the workmen are directed by catchwords or sig¬ natures, at the bottom of the pages. When the leaves are thus folded, and arranged in proper order, they are usually beaten upon a stone, with a heavy hammer, to .make them solid and smooth, and are then condensed in a press, or by passing through iron rollers. After ihis preparation, they are sewed in a sewing-press, upon 16 * 186 COMBINING FLEXIBLE FIBRES. transverse cords, or packthreads, called bands, to receive which, notches are previously sawed in the back. The number of bands is usually six to a folio, and five for quartos, or any smaller size. The backs are now brushed over with glue, and the ends of the bands opened, and scraped with a knife, that they may be more conveniently fixed to the pasteboard sides ; after which, the back is turned with a hammer, the book being fixed in a press, between boards, called backing-boards, in order to make a groove, for admitting the pasteboard sides. When these sides are applied, holes are made in them, for drawing the bands through, the superfluous ends are cut off, and the parts are hammered smooth. The book is next pressed, for cutting, which is done by a particu¬ lar machine, called the plough, to which is attached a knife. It is put into a press, called the cutting-press, betwixt two boards, one of which lies even with the press, for the knife to run upon ; and the other above, for the knife to cut against. After this, the pasteboards are cut square, with a pair of iron shears ; and the colors are sprinkled on the edges of the leaves, with a brush, made of hog’s bristles. The pasteboard sides are now covered, by pasting upon them leather, or whatever other material is intend¬ ed to form the outside. The sprinkling, or marbling, of the covers is performed, with a brush and a coloring li¬ quid. The covers are glazed, by applying to them the white of an egg, and rubbing them with a heated steel- polisher. A thin piece of morocco is glued upon the back, to receive the lettering, which is impressed with gold-leaf and heated types. Cloth Binding is a recent improvement, in which a piece of cloth, usually dyed cotton, is embossed with ornamental figures, by passing it through a roller-press, be¬ tween engraved steel cylinders. It is afterwards pasted upon the volume, in the same manner as leather. Cloth binding is, executed with more despatch, and at less ex¬ pense, than that with leather. ARTS OF HOROLOGY. 187 Works of Reference.—Gray’s Treatise on Spinning Machin¬ ery, 8vo. 1819 ;— Duncan’s Essay on the Art of Weaving, 8vo. 1808 ;— Guest’s History of the Cotton Manufacture, 4to. 1823 ;— Borgnis’ Mechanique Appliquee aux Arts, 1818 ; tom. 7, Machines a Confectionner les Etoffes ;— Ure, The Cotton Manufacture of Great Britain, 8vo. 1836 ;— Lardners’ Cabinet Cyclopedia, 12rno. vol. xxii. entitled Silk Manufacture ;— Rees’ Cyclopedia, articles Cotton Manufacture, Woollen Manufacture, &c. ;—Edinburgh Encyclope¬ dia, articles Cotton Spinning, Cloth Manufacture, &c. Much of the machinery, invented in this country, is not described in European works. CHAPTER XIX. ARTS OF HOROLOGY, Sun Dial, Clepsydra, Water Clock, Clock Work, Maintaining Power, Regulating Movement, Pendulum, Balance, Scapement, Descrip¬ tion of a Clock, Striking Part, Description-of a Watch. H OROLOGY, or the art of measuring time, has received the attention, and exercised the ingenuity, of mankind, from the earliest periods. The lapse of thought, and the routine of ordinary occupation, afford hut imperfect indi¬ cations of the real passage of time ; and the only exact standard, by which periods of duration can be estimated, is that of governed and regular motion. Sun Dial. —'L'he diurnal movement of the earth, with relation to the heavenly bodies, is the most perfect stand¬ ard of admeasurement, for large periods of time. It is the only one, by which the brute creation, and the unciv ilized part of mankind, govern their habits of life. Tliis motion has been converted to practical use, for measuring small periods, by the employment of the sun-dial, an in¬ vention, apparently, of great antiquity, in which the falling of a shadow, on a surface opposite to the sun, indicates the hour of the day. 'I'he sun-dial was known to the aiicient Egyptians, Chinese, and Bramins, and was used, l>y the latter, for astronomical purposes. It appears, also, to have been knowm to the Jews, in the time of Ahaz, about seven hundred and forty years before Christ. 188 ARTS OF HOROLOGT. The first sun-dial at Rome was set up by Papiriiis Cur¬ sor, about three hundred years before Christ; previously to which time, Pliny tells us, tliere is no mention of any account of time, but by the sun’s rising and setting. . At Athens, there is now standing an octagonal build¬ ing, erected by Andronicus Cyrrhestes, and commonly called the Tower of the Winds. It is shown in Fig. 44 Vol. I. Upon each of the eight sides of this building, is a flying figure, carved in relief, representing the partic ular; wind which blew against that side. Upon each side, was also placed a vertical sun-dial; the gnomon^ or index, which cast the shadow, projecting from the side, while the lines, indicating the hour, were cut upon the wall. On the top, according to Vitruvius, was the figure of a Triton, which turned with the wind, in the same manner as a mod¬ ern weathercock. The lines of the dial, upon the wall, are distinctly extant, at the present day ; and, although the gnomons have disappeared, the places where they were inserted are still visible. Clepsydra .—Since the sun-dial could be used, only in the day time, and in clear weather, a diflerent instrument was invented by the ancients, to be used within doors, at all times ; and to this was given the name of clepsydra. The clepsydra was formed by a vessel of water, having a minute perforation in the bottom, through which the water issued, drop by drop. It fell into another vessel, in which a light body floated, having attached to it an index, or graduated scale. As the water increased in the receiv¬ ing vessel, the floating body rose, and, by its regularly increasing height, furnished an approximation to the cor¬ rect indication of time.* The original clepsydra was but a rude instrument, and must have given imperfect indications of the true divisions of time. When the vessel was first filled, the drops must have fallen faster, owing to the greater height and pres- * This instrument was invented in Egypt, but was brought into Rome from Athens. Pompey% while Consul, introduced it into the Roman Senate House ; and the orators were obliged to limit the length of their speeches, by its divisions of time, so that Pompey is designated, by one of the historians, as the first Roman who put bridles upon eloquence. WATER-CLOCK.-CLOCK-WORK. 189 sore of the fluid ; and, in proportion as it became empty, the dropping would be slower, in consequence of the di¬ minution of this pressure. The disadvantage, however, was remedied, in various ways, by the employment of two vessels, one of which was kept constantly full, by a supply from the other; and thus the water, being always at the same height, furnished its drops, under an equable pressure. Water Clock .—An instrument, called a water-clock, was in use, at a much later date, and was a subject of extensive manufacture, in some parts of Europe, a few centuries ago. Several modes of constructing this instru¬ ment were devised ; but the following is one of the most ingenious. A tight, hollow’ cylinder, PI. IV. Fig. 4, is suspended by cords, w^ound round its axis, which will unwind, as it runs down. It has its interior divided into several compartments, situated like the buckets of a wa¬ ter-wheel. These compartments communicate with each other, by a minute aperture, through which water can pass slowly, from one compartment to another. Before the machine is put in motion, a small quantity of water is introduced into the low’er compartments. As the cyl¬ inder descends, by the unwinding of the cords, it is obliged to revolve on its axis, until the lower compartments, which contain the w ater, have risen so far on the ascending side, as to produce an equilibrium. It can then unwind no faster than the water escapes, from one compartment to another, through the minute apertures. As this requires a considerable time, the cylinder may occupy a day, if required, in descending from the top to the bottom of the frame, to which it is attached. And, if the sides of the frame be marked with the hours of the day, the axis of the cylinder, as it j)asses by them, will indicate the time of the day, with as much accuracy as so imperfect a machine permits. Clock Work .—In modern days, all other methods of measuring time have given place to the equable motion, produced by the action of machinery on the pendulum and balance. Timekeepers, constructed on this princi¬ ple, began to be known in Europe, about the fourteenth 190 ARTS OF HOKOLOer. century, but were formed in a rude and imperfect man-^ iier, until the middle of the seventeenth. Since that pe¬ riod, the learning of philosophers, and the ingenuity of artists, have been extensively applied to their improve¬ ment ; and few subjects, connected with the mechanic arts, have called forth more inventive acuteness, elabor¬ ate experiment, and exact calculation. Before proceeding to a description of the entire me¬ chanism of a clock, or watch, it will be useful to attend to some of the general principles, and essential parts, of a timekeeper. These will be most easily made intelligi¬ ble, by directing the attention to the following subjects. 1. The maintaining power. 2. The regulating move¬ ment. 3. The method of connection. JMaintaining Power .—The force, which is employed to sustain the motions of timekeepers, does not require to be of a powerful kind. It must, however, be steady and uniform, in its action. Gravity and elasticity, applied through the medium of weights and springs, are the only means now employed, to communicate motion to these machines. In clocks, the maintaining force is usually derived from a weight. A weight acts with perfect uni¬ formity, from the beginning to the end of its descent, pro¬ vided the line, which suspends it, is of equal size through¬ out, and that this line is wound upon a true and perfect cylinder. In portable timekeepers, the w’eight, for ob¬ vious reasons, cannot be employed ; and the spring., al¬ though a less perfect and equable power, is obliged to be substituted. From the oldest clocks which remain, it appears, that the spring was in use before the weight; and one of the first, ever made, is still preserved at Brussels, in wdiich the spring is an old sw'ord-blade, from which a piece of catgut is w^ound upon the cylinder of the first wheel: The principal difficulty in the use of the spring is, that its action is unequal, and that the more it is bent, the greater force it exerts, to return to its natural situa¬ tion. The spring of a watch, as it is now used, is a long plate of steel, coiled up into a spiral form. From the outside of this, proceeds a chain, which is attached, not to a cylinder, as is done with the weight, but to a spiral nEGULATlxNG MOVEMENT.—PENDULUM. 191 roller, called a fusee, which, by its conical form, gives to the spring an increased mechanical advantage, in propor¬ tion as its power diminishes. The fusee has already been described, on page G2. In some of the watches which are now^ made, the fusee and the chain are dispensed with. The barrel, which incloses the spring, has a toothed circle on its outside, wdiich turns round, as the spring unwinds, and gives mo¬ tion to the machinery. But, in this case, the spring is made larger than common, and only the middle part of its action is used, it being never wound up so far, as to call forth its greatest strength, nor suffered to run down, so far as to be materially weakened. - Regulating ^Movement .—In the mechanism of clocks and watches, it is necessary, so far to retard the move¬ ment of the maintaining force, i. e., of the weight or spring, that it may be hours and days in expending itself, and that the timekeeper may require to he wound up, only at distant and convenient periods. This is, in part, ef¬ fected, by the successive combination of wheels and pin¬ ions, the last of which turns round many hundred times, while the first turns round once. But, if a timekeeper possessed only wheels and pinions, it would run down, wiili a rapidly accelerated motion, in the course of a few seconds. It becomes, therefore, necessary, to connect with it another motion, which cannot be accelerated, be¬ yond a certain degree, by any given force. This mo¬ tion is obtained, in clocks, from the pendulum^ and, in watches, from the balance ; and it is the one which it was proposed to consider, as the second head, under the name of the regulating movement. Pendulum .—A pendulum is a weight, cajiable of vi¬ brating about a point, from which it is suspended. If the curve, in which the pendulum moves, be a circular arc, it is necessary, that tlie length of the vibrations should be exactly equal ; otherwise, the pendulum w ill not keep true time. But, if the curve be a cycloidal one, the pendulum will move, back and forward, in equal times, whatever be the length of its vibrations. In practice, it is found diffi¬ cult to make a pendulum move in a cycloidal path, with- 192 ARTS OF HOROLOGI. out too much friction. It is, therefore, customary, in clocks, to use pendulums, moving in circular arcs, these arcs being made to approximate to cycloids, by being as short as possible. Pendulums, when set in motion, would continue to vi¬ brate forever, were it not for the retarding efl’ect of fric¬ tion, and the resistance of the atmosphere. The former of these is partly obviated, by hanging the pendulum upon a thin spring, and the latter, by forming it with a sharp edge. Still, a considerable force is requisite to sustain the motion, and this force, in clocks, is derived from the weight. That pendulums may vibrate in equal periods, and thus furnish a correct measure of time, it is necessary, that they should always be of uniform length ; for pendulums of different lengths differ in their vibrations, as the square roots of their lengths. Now, such is the effect of heat, in expanding all known substances, particularly metals, that the same pendulum is always longer in summer than it is in winter, and sufficiently so, to affect the correctness of the timepiece, to which it is attached. To remedy this difficulty, various ingenious contrivances have been resort¬ ed to, the most common of which are, combinations of metals, so connected, as to expand in opposite directions, counterbalancing each other, so as to keep the centre of oscillation in one place. This is sometimes effected, in the gridiron pendulum, by combining bars, or rods, of steel and brass ; and, in the mercurial pendulum, by en¬ closing a quantity of quicksilver, in a tube, near the bot¬ tom of the pendulum. Balance —As the pendulum depends upon the force of gravity, for its motions, it obviously cannot be employed for watches, or portable timekeepers, which are liable to change their position. A substitute is found in the bal~ ancCf which is commonly a wheel, moving on an axis, and which, when thrown, backward and forward, by oppo¬ site applications of the moving force, performs its vibra¬ tions in equal times. The balance is liable to the same irregularities, from expansion and contraction, as the pen-* dulum, and is corrected in a similar manner ; and watches SCAPEMENT, 193 50 best, vrhen they are kept in the uniform heat of the body. The quantity of matter, accumulated in the balance- wheel of a common watch, is so extremely small, that it seems impossible, that it should exert a perfect regula¬ ting power. The want of weight, however, is, in some measure, made up, by causing it to perform large vibra¬ tions, and to move with great velocity. The rim of the balance-wheel, in a good watch, frequently moves through ten inches in every second. This velocity is produced by the hair-spring, which throws the balance back to the point of equilibrium, as fast as it is thrown out, in either direction, by the moving force; thus per¬ forming for the liaJance, what gravity does for the pen¬ dulum. If the hair-spring be taken away, a watch will lose more than twelve hours in twenty-four, and go much more irregularly. The operation of the common regula¬ tor of a watch is, to'tighten, or relax, this hair-spring, by making its effective part longer or shorter, thus accelera¬ ting, or retarding, the speed of the balance. Scapement .—It remains to consider the third part, or scapement, by which the rotary motion of the wheels is converted into the reciprocating one of the pendulum and balance. In the scapement, a certain part, connected with the pendulum, or balance, is put in the way of the last, or most rapid, wheel, so that only one tooth of this wheel can escape by it, during each vibration. Thus, the pendulum, or balance, while it receives its motion from tliis wheel, becomes, in its turn, tlie regulator of its velo¬ city. The crutch, or anchor-scapement, uSbd in clocks, and the common pallet-scapement with a contrate-wheel, which is the kind most extensively used in watches, have been already explained, under the head of Machinery^ page 72. The horizontal scapement. Fig. 183, con¬ sists of a wheel. A, with elevated teeth, the outer surface of which is curved obliquely. These teeth act upon the edges of a hollow half cylinder, C, the axis of which is parallel to that of the wheel, and carries the balance upon one of its extremities. When a tooth of the scape-wheel II. 17 XU. I9i ARTS OF HOROLOGF. Fig. 183. strikes the first edge of the cylinder, it causes it to re¬ cede, moving the balance in one direction. The tooth then enters the hollow part of the cylinder, and strikes upon the opposite side. Before it can escape, the cylin¬ der is obliged to turn in the opposite direction, and thus a vibrating movement is kept up, in the cylinder and bal¬ ance. A multitude of other scapements have also been in troduced, by difierent artists, varying from each other, in the complication of their structure, and accuracy of their movements. But these must, necessarily, be omitted. The operation of the simpler forms, already described, will be more intelligible, taken in connexion with the wheel-work, next to be noticed. /y// . iJdescription of a Clock .—In PI. IV. several views are given of the mechanism of a clock, consisting of the go¬ ing part., which moves constantly, and carries the hands; and the striking part, which announces the hour. Fig. 1 , PI. IV. is an elevation of the clock, with the wheels seen edgewise, showing the going part; the striking movements being omitted, in this figure, to avoid confu¬ sion. Fig. 2, is a front view of the wheel-work of both going and striking parts ; and Fig. 3, is the dial-work, or mechanism, immediately under the dial, or face of the clock, and is that part which puts the striking train in mo¬ tion, every hour. A clock of this kind contains two in¬ dependent trains of wheel-work, each with its separate first mover. One is constantly going, to indicate time, by tlie hands on the dial-plate; the other is put in motion, once in an hour, and strikes a bell, to tell the hour at a distance. The part, marked [a,] in Figs. 1 and 2, is DESCRIPTION OF A CLOCK. 195 tlie barrel of the going part ; il has a catgut band, [i,] wound round it, suspending the weight, which keeps the clock in motion. The part, marked 96, is a wheel, call¬ ed the first, or great wheel, of ninety-six teeth upon the end of a barrel, turning a pinion, 8, of eight leaves, on an arbor,* which carries the minute-hand ; also, 64, is a wheel of sixty-four teeth, on the same arbor, called the centre-wheel, turning the wheel, 60, by a pinion of eight leaves on its arbor. This last wheel gives motion to the pinion of eight, on the arbor of the swing-wheel, 30, which has thirty teeth. The parts [d/i] are the pallets of the scapement, fixed on an arbor, [e,] Fig. 1, going through the back plate of the clock’s frame, and carrying a long lever, [/.] This lever has a small pin, projecting from its loiver end, going into an oblong hole, made in the rod, B, of the pendulum. The pendulum consists of an inflexible metallic rod, siis pended by a very slender piece of steel spring, D, from a brass bar, E, screwed to the frame of the clock, having a weight at its lower end, not seen in the figure; in the present case, thirty-nine and one eighth inches from the suspension, D. When this pendulum is moved from the perpendicular line, in either direction, and suffered to fall back again, it s\vings nearly as much beyond the perpen¬ dicular, on the contrary side, and then returns. This it will continue to do, for some time ; and each of these vi¬ brations will be performed in one second of time, when the pendulum is of the above length. This is the meas¬ urer of the time ; and the office of the clock is only to in¬ dicate the number of vibrations it has made, and to give it a small impulse, each time, to keep it going, as the re¬ sistance of the air, and elasticity of the spring, D, would otherwise, in a short time, cause it to stop. By the ac¬ tion of the weight, applied to the cord, [6,] which is called the maintaining power, the wheels are all turned round ; * The terms arbor, shaft, axle, and axis, are synonymously used by mechanics, to express the bar, or rod, which passes through the centre of a wheel. The terminations of a horizontal arbor are called gud¬ geons, and of an upright one, frequently, pivots. The term axis, in a more exact sense, may mean merely the longest central diameter, or a diameter about which motion takes place. ARTS OF HOROLOGY. lyo and if the pallets [d and /t] were removed, the swing- wheel, 30, would revolve, with great velocity, in the direc¬ tion from 30 to [d,] until the weight reached the ground. The teeth of these pallets are so placed, that one of them always engages the wheel, and prevents it from turning more than half a tooth at a time. In the figure, the pallet [d] has the nearest tooth of the wheel resting on it, and the pendulum is on the side [/t] of the perpendicular. When it returns, it moves the pallet, [d,] so as to allow the tooth of the wheel to slip off; but, in the mean time, the pallet [/i] has interposed its point, in the way of the tooth next it, and stops the wheel, till the next vibration, or second. The distance between the two pallets [d and h] is so adjusted, that only half a tooth of the wheel escapes, at each vibration; and, as the wheel has thirty teeth, it will revolve once in sixty vibrations, of one second each, or in one minute ; consequently, a hand, on the arbor of this wheel, will indicate seconds, on the dial-plate, F, which is a circle, divided into sixty. The pinion of eight, on its arbor, is turned by a wheel of sixty, which, conse¬ quently, will turn once in seven turns and a half of the other, or in seven minutes and thirty seconds, or, in one eighth of an hour. Its pinion of eight is moved by a wheel of sixty-four, or eight times itself, which will turn in one eighth part of the time. This will be an hour ; and, there¬ fore, the arbor of this wheel carries the minute-hand of the clock. The great wheel of 96, being twelve times the number of the pinion eight, will turn once in twelve hours, and the barrel, [a,] with it. The cord of catgut goes round sixteen times, so that the clock will go eight days. The hour-hand of the clock is turned by the wheel- work, shown in Figs. 1 and 3. On the end of the arbor of the centre wheel, 64, a tube is fitted, so as to go round with it, by friction. This carries the minute-hand ; and, if the clock should require correction, the hand may be slipped round, without moving the wheels. This tube has a pinion of forty teeth on its lower end, indicated by a dotted circle. This turns another wheel, 40, of forty teeth, which has a pinion of six teeth on its arbor, turning a wheel, 72, of seventy-two teeth. The two wheels, 40, STRIKING PART. 197 will both turn in an hour; and 72, in twelve hours. The arbor of this wheel has the hour-hand, and is a tube, going over the arbor of the minute-hand, so that the two hands are concentric. The barrel [a] is fitted to an arbor, com¬ ing through the plate of the clock, and filed square, to put on a key, to wind up the weight. The great wheel, 96, is not fixed fast to the arbor, but has a click on it, which takes the teeth of a ratchet-wheel, cut on the barrel; so that the barrel may be turned in one direction, to wind up the weight, without the wheel; but, by the descent of the weight, the wheels will be turned with the barrel, by the click. Striking Part .—Having now considered the going part of the clock, it remains to describe the mechanism by which the hour is struck. In Fig. 2, 78, is a great wheel of seventy-eight teeth, provided with a barrel and click, as in 96 ; it turns a pinion of eight. On the same arbor is a wheel, 64, turning a pinion of eight, on the arbor of the wheel [o] of forty-eight. This turns another pinion of eight, and wheel Qi] of forty-eight, which turns a pin¬ ion of six, on the same arbor, with a thin vane of metal, seen edgewise, which is called the fly., and which, by the resistance of the air to its motion, regulates the velocity of the wheels. The wheel, 64, has eight pins projecting from it, which raise the tail [n] of the hammer, as they revolve. The hammer is returned, violently, when the pins leave its tail, by a spring, [m,] pressing on tbe end of a pin, put through its arbor, and strikes the bell. The hammer and bell are behind the plate, and, therefore, unseen. There is a short ^ spring, [/,] which the other end of the pin through the ar¬ bor touches, just before the hammer strikes the bell. Its use is, to lift the hammer off the bell, the instant it has struck, that it may not stop the sound. The pins in the wheel, 64, must pass by the hammer-tail seventy-eight times, in striking the twelve hours, l-f-2-j-3-j-4-|-5-t-6-|- 7 -j-8+9-[-10-l-l 1 + 12=78 ; and, as its pinion has eight leaves, each leaf of the pinion ans\vers to a pin in the wheel, 64. Now, as the great wheel has seventy-eight teeth, it will turn once in twelve hours, the same as the 17 "^ 198 ARTS OF HOROLOGV. Other great wheel, 90. In the wheel, 64, eight of its teeth correspond to one of the pins of the hammer, and, as the pinion of the wheel [o j has eight teeth, it (wheel o) will turn once, for each stroke of the hammer. By the remaining wheels, one, [o,] multiplying six times, and the other, [p,] eight times, the fly will turn 6X8=48 times, for one turn of [o,] which answers to one stroke of the hammer. Fig. 3, is also mechanism, relating to the striking part. Behind [r,] there is a small pinion, of one tooth, called the gathering-pallet, on the arbor of the wheel, [o,] which, consequently, turns once, for each stroke of the hammer. The part, marked [Snr,] is a portion of a large wheel, and is called the rack. The part [^] is an arm attached to the rack, whose end rests against a spiral plate, V, called the snail, which is fixed on the tubular arbor, be¬ fore described, of the hour-hand and wheel, 72, and turns round with it once in twelve hours. The snail is divided into twelve equal angles, of thirty degrees each, and, as it turns, each of these answers to an hour. The circular arcs, forming the circumference of the snail, are struck from the centre of the arbor, between each division, with a different radius, decreasing a certain quantity, each time, in the order of the hours. The circular part of the rack, 14, is cut into teeth, each of which is of such a length, that every step upon the snail shall answer to one of them. At [to,] is a spring, pressing against the tail of the rack, and acting to throw the arm of the rack against the snail. The part [g-] is a click, called the hawk’s-bill, taking into the teeth of the rack, and holding it up, in opposition to the spring, [to.] The part [i/c] is a three-armed detent, called the warning-piece. The arm [A:] is bent at its end, and passes through a hole, in the front plate of the clock, so as to catch a pin, placed in one of the arms of the wheel, [p,] Fig. 2, and which describes the dotted circle, in Fig. 3. The other arm [i] stands, so as to fall in the way of a pin, in the wheel, 40. In the pre¬ sent position of the figure, the wheels of the striking train are in motion, and would continue turning, until the gath¬ ering-pallet at [r] which turns once, at each stroke of the hammer, by its tooth lifts the rack, [s,] in opposition STRIKING PART. 199 to the spring, [lo,] one tooth, each turn ; and the hawk’s- bill [^] retains the rack, until a pin, in the end of the rack, is brought in the way of the Jevef of the gathering- pallet, [r,] and stops the wheels from turning any further. It is in this position, with the rack wound up, till its pin arrests the tail, [r,] that we shall begin to describe the operation of the striking of the clock. 'I’he wheel, 40, as has been said before, turns once in an hour ; and, consequently, at the expiration of every hour, the pin in it takes the end, [i,] and moves it to¬ wards the spring near it. This depresses the end, [k,] until it falls in the circle of the motion of the pin, in the wheel, [p,] Fig. 2. At the same time, the short tail de¬ presses one end of the hawk’s-bill, and raises the other, [^,] so as to clear the teeth of the rack, [s.] Immedi- diately, the spring [lo] tlirows the rack back, until the end of its tail [f] touches that part of the snail which is nearest it. When the rack falls back, the pin in it is moved clear of the gathering-pallet, [r,] and the wheels are set at liberty. The maintaining power puts them in motion ; hut, in a very short time, before the hammer has struck, the pin in the w’heel [p] falls against the end of [fc,] and stops the whole. This operation happens, a few minutes before the clock strikes, and this noise of the wheels turning is called the warning. When the hour is expired, the wheel, 40, has turned so far, as to allow the end of [t] to slip over its pin, as in the figure. The small spring, pressing against it, raises the end, [k,] so as to be u’ithin the circle of the pin, in the wheel, [p,] Fig. 2. Every obstacle is now removed, and the wheels run on the pinion ; the wheel, 64, raises the hammer, [r,] and it strikes on the bell ; the gathering-pallet [r] takes up the rack, one tooth at each turn, the hawk’s-bill [g-] re¬ taining it, until the pin [.r] in the rack, comes under the gathering-pallet, [r,] and stops the motion of the whole machine, till the pin in the wheel, 40, at the next hour, takes the warning piece, [tk,] and repeats the operation we have now described. As the gathering-pallet turns once, for each blow of the hammer, and its tooth gathers up one tooth of the rack, at each turn, it is evident, that 200 ARTS or HOROLOGY. the number of teeth, which the rack is allowed to fall back, limits the number of strokes the hammer will make. This is done by the rack’s tail, [<,] resting on the snail. Each step of the snail answers to one tooth of the rack, and one stroke of the hammer. At each hour, a fresh step of the snail is turned to the tail of the rack, and, by this means, the number of strokes is made to increase one, at each time, from one to twelve. Description of a Watch .—In PI. V., several views are given of the construction of a common portable watch. Fig. 1, represents the wheel-work, immediately beneath the dial-plate, and also its hands, the circles of hours and minutes being marked, though the dial, on which these are engraved, is removed. Fig. 2, is a plan of the wheel- work, all exhibited at one view, for which purpose, the upper plate of the watch is removed. Fig. 3, is a plan of the balance, and the w*ork situated upon the upper plate. Fig. 4, shows the great wheel, and the pottance-wheel, detached. Fig. 5, the spring-barrel, chain, and fusee, detached ; and Fig. 6, is an elevation of all the move¬ ments together, the works being supposed to be opened out into a straight line, to exhibit them all at once. Fig. 7, is a detached view of the balance, together with the scaperaent, in action. The principal frame, for supporting the acting parts of the watch, consists of two circular plates, marked C and in the figures. Of these, the former is called the upper plate, and the latter, the pillar-plate, from the cir¬ cumstance that the four pillars, EE, which unite the two plates, and keep them a proper distance asunder, are fas¬ tened firmly into the lower plate ; while the other ends pass through holes, in the upper plate, C, and have small pins put through the ends of the pillars, to keep the whole together. By drawing out these pins, the watch may be taken to pieces. The pivots of the several wheels being received in small holes, made in these plates, they, of course, fall to pieces, as soon as the plates are separated. The maintaining power is a spiral steel spring, which is coiled up close, by a tool used for the purpose, and put into a brass box, called the barrel. ^ It is marked A, in DESCRIPTION OF A WATCH. 201 all the figures, and is shown separate, in Fig. 5, with the spring in it. The spring has a hook, at the outer end of its spiral, which is put through a hole, [a,] Fig. 5, in the side of the barrel, and riveted fast to it. The inner end of the spiral has an oblong opening, cut through it, to receiv'e a hook upon the barrel arbor, B, Fig. 5. The pivots of this arbor pass through the top and bottom of the barrel, and one of them is filed square, to hold a ratchet-wheel, [ 6 ,] Figs. 1 and 6 , which has a click, and keeps the arbor from turning round, except in one direc¬ tion. The two pivots of the arbor are received in pivot- holes in the plates, CD, of the watch, and the pivot, which has the ratchet-wheel upon it, passes through the plate. The wheel marked [ 6 ,] Figs. 1 and 6 , with its click, is, therefore, on the outside of the pillar-plate, D, of the watch. The top of the barrel has a cover, or lid, fitted into it, through which the upper pivot of the arbor pro¬ jects ; thus, the arbor of the barrel is to be considered as a fixture, the click of the ratchet-wheel preventing it from turning round, while the interior end of the spiral spring, being hooked, assists in rendering it stationary. The barrel, thus mounted, has a small steel chain, [(/,] Figs. 2 and 6 , coiled round its circumference, and attached to it by a small hook of the chain, which enters a little hole, made in the circumference of the barrel, at its upper end. 'riie other extremity of this chain is hooked to the lower part of the fusee, marked F, Figs. 2 , 5, and 6 , and the chain is disposed, either upon the circumference of the barrel, or in the spiral groove, cut round the fusee for its reception, the arbor of which has pivots at the ends, which are received into pivot-holes, made in the plates of the watch. One pivot is formed square, and projects through the plate, to fit the key, by which the watch is wound up. It is evident, that, when the fusee is turned by the w'atch-key, it will wind the chain, off the circumference of the barrel, on Itself; and, as the outer end of the spring is fastened to the barrel, and the other is hooked to the barrel-arbor, which, as before mentioned, is prevented from turning, by the click of the ratchet-wheel, [a6,] the spring will be coiled up into a smaller compass than be- 202 ARTS OF HOROLOGY. fore. Its reaction, therefore, when the key is taken off, will turn the barrel, and, by the chain, turn the fusee, and give motion to the wheels of the watch. The fusee has a spiral groove cut round it, in which the chain lies ; this groove is cut by an engine, in such a form, that the chain shall pull from the srnallest part, or radius, of the fusee, when the spring is quite wound up, and, therefore, acts with its greatest force on the chain. From this point, the groove gradually increases in diameter, so that, as the spring unwinds, and acts with less power, the chain oper¬ ates on a larger radius of the fusee ; and the eftect, upon the arbor of the fusee, or the toothed wheel attached to it, will always be equal, and cause the watch to go with regularity. To prevent too much chain being wound upon the fu see, and, by that means, breaking the chain, or over¬ straining the spring, a contrivance, called a guard-gut^ is added. It is a small lever, [c,] Fig. 2, moving on a stud, fixed to the upper plate, C, of the watch, and press¬ ed downwards by a small spring, [/.] As the chain is wound up, upon the fusee, it rises in the spiral groove, and lifts up the lever, until it touches the upper plate. It is then in a position to intercept the edge, or tooth, [g’,] of the spiral piece of metal, seen on the top of the fusee, and thus stops it from being wound up any further. The power of the spring is transmitted to the balance, by means of several toothed wheels, which multiply tlie number of revolutions, which the chain makes on the fu¬ see, to such a number, that, though the last, or balance- wheel, turns nine and one half times every minute, the fu¬ see will, at the same time, turn so slowly, that the chain will not be drawn off from it, in less than twenty-eight or thirty hours, and it will make only one turn, in four hours This assemblage of wheels is called the train of the watch. The first toothed wheel, G, is attached to the fusee, and is called the great wheel. It is shown separa¬ ted from the fusee, in Fig. 4, having a hole through the centre, to receive the arbor of the fusee, and a projecting ring upon its surface. The under surface of the base of the fusee is shown in Fig. 5, at F, having a circular DESCRIPTION OF A WATCH. 203 cavity cut in it, to receive the corresponding ring upon the great wheel, G, Fig. 4. A ratchet-wheel [i] is fixed fast upon the fusee arbor, and sunk within the cav¬ ity, excavated in the lower surface of the fusee. When the wheel and fusee are put together, a small click, [/i,] Fig. 4, takes into the teeth of the ratchet, [i.] As the fusee is turned by the watch-key, to wind up the watch, this click slips over the sloping slides of the teeth, with¬ out turning the great wheel ; but, when the fusee is turned the other way, by drawing the chain from the spring-bar¬ rel, the click catches the teeth of the ratchet-wheel, and causes the toothed wheel to turn with the fusee. The great wheel, G, has forty-eight teeth on its cir¬ cumference, which take into, and turn, a pinion of twelve teeth, fixed on the same arbor with the Centre-wheel, H, so called, from its situation in the centre of the w'atch ; it has fifty-four teeth, to turn a pin¬ ion of six leaves, on the arbor of the Third icheel, I, which has forty-eight teeth. It is sunk in a cavity, formed in the pillar-plate, and turns a pinion of six, on the arbor of the Contrule-wheel, K, which has forty-eight teeth, cut parallel with its axis, by which it turns a pinion of six leaves, fixed to The balance-wheel, L. One of the pivots of the arbor of this w'heel turns in a frame, M, called the pottance, or potence, fixed to the upper plate, and shown separately, in Fig. 4. The other pivot runs in a small piece, fixed to the upper part, called the counter pottance, not shown in anv of the figures ; so that, when the two plates are put together, the balance-wheel pinion may work into the teeth of the contrate-W'heel, as shown in Fig. G. The balance-wheel, L, has fifteen teeth, by which it impels the balance, [op.] The arbor of the balance, which is called the verge, has two small leaves, or pallets, projec¬ ting from it, nearly at right angles to each other. These are acted upon by the teeth of the balance-wheel, L, in such a manner, that, at every vibration, the balance re¬ ceives a slight impulse to continue its motion ; and every vibration, so made, sufiers a tooth of the wdieel to escape. 204 ARTS OF HOROLOGY. or pass by ; whence this part is called the scapement ol the watch, and constitutes its most essential part. The wheel, L, is sometimes called the scape-icheel^ or crown¬ wheel. Its action is explained by Fig. 7, which shows the wheel, and balance, detached. Suppose, in this view, the pinion [/i] on the arbor of the balance-wheel, or crown-wheel, [iA;,] to be actuated by the main-spring, which forms the maintaining power, by means of the train of wheel-work, in the direction of the aiTow, while the pallets, [m and n,] attached to the axis of the balance, and standing at right angles to each other, or very nearly so, are long enough to fall in the way of the ends of the sloped teeth of the wheel, when turned round, at an angle of forty-five degrees, so as to point to opposite directions, as in the figure. Then a tooth in the wheel below, for instance, meets with the pallet, [n,] supposed to be at rest, and drives it before it, a certain space, till the end of the tooth escapes. In the meantime, the balance, [os/)r,] attached to the axis of the pallets, continues to move in the direction [rosp,] and winds up the small spiral, or hairspring, [r,] and aids the spring, which now unbends itself, till it comes to its quiescent position, then swings beyond that point, partly, by the im¬ pulse from the maintaining power on the pallet, [m,] and partly, by the acquired momentum of the moving balance, particularly when this pallet [m] has escaped. At length, the pallet [w] again meets with the succeeding tooth, and is carried backward by it, in the direction in which the balance is now moving, till the maintaining power and force of the unwound spring, together, overcome the mo- DESCRIPTIOiN OF A WATCH. 205 mentum of the balance, during which time, the recoil of the balance-wheel is apparent, and, also, of the second¬ hand, if the watch has one, its place being on the arbor of the contrate-wheel. Then the wheel brings the pallet [n] back again, till it escapes ; and the same process takes place with the pallet, [in,] as has been described with re¬ spect to pallet, [n.] Thus, two contrary excursions, or oscillations, of the balance take place, before one tooth has completely escaped ; and, for this reason, there must always be an odd number of teeth in this wheel, that a space on one side of the wheel may always be opposite to a tooth on the other, in order that one pallet may be out of action, while the other is in action. The upper pivot of the verge is supported in a cover, screwed to the upper plate, as shown at N, in Fig. 6, which extends over the balance, and protects it from vio¬ lence. The lower pivot works in the bottom of the pot- tance, M, at [/,] Fig. 4. The socket, for the pivot of the balance-wheel, is made in a small piece of brass, [v,] which slides in a groove, made in the pottance, as shown in Fig. 4 ; so that, by drawing the slide in or out, the teeth of the balance-wh^el shall just clear* one pallet, be¬ fore it takes the other ; and, upon the perfection of this adjustment, which is called the scaping of the watch, the performance of it very greatly depends. It now remains to show the communication of this mo¬ tion to the hands of (he watch, which indicate the time on the dial-plate. The hands are moved by the central arbor, which comes through the pillar-plate, and projects a considerable length. It has a pinion of twelve leaves, called The common pinion, [to,] Fig. 6, fitted upon it, the axis of which is a tube, formed square at the end, to fix on the minute-hand, W. It fits tight upon the projecting arbor of the centre-wheel; and, therefore, turns with it, but will slip round to set the hands, when the watch is wrong, and requires to be rectified. The common pin¬ ion is situated close to the pillar-plate, and its leaves en¬ gage the teeth of The minute-wluel, X, Figs. 1 and 6, of forty-eight II. IS XII. 206 ARTS OF HOROLOGY. teeth, which is fitted on a pin fixed in the plate, and its pinion, [a;,] of sixteen leaves, which is fixed to it, turns The hour-toheel., Y, of forty-eight teeth. The arbor of this is a tube, which is put over the tube of the cannon’ pinion, carrying the minute-hand, and has the hour-hand, Z, fixed on it, to indicate the time upon the dial-plate. Thus, by the cannon-pinion, [ro,] which is to the minute- wheel, X, as one is to four, and the pinion -[a^] of this, which is to the hour-wheel, Y, as one is to three, the hour- wheel, Y, and its hand, [r,] though concentric with the cannon-pinion and minute-hand, make but one revolution, during twelve revolutions of the other ; therefore, one turns round in an hour, and the other turns round once in twelve hours, as the figures on the dial show. It is necessary to have some regulation, by which the rate of the watch’s movement may be adjusted ; for, hith¬ erto, we have only spoken of making the watch keep al¬ ways to a uniform, or certain rate of, motion ; but it is necessary to make it keep true time. This can be done by two means ; either by increasing or diminishing the force of the main-spring, which increases or diminishes the arc which the balance describes ; or it may be done, by strengthening or weakening the hair-spring, which will cause the balance to move quicker or slower. The hair-spring, otherwise called the pendulum-spring, [ 7 ,] Fig. 3, is fixed to a stud, upon the plate, [c,J by one end, and is attached to the verge of the balance, by the other. ^•"^The regulation is effected by means of what is called the curb. This is a small lever, [r,] Fig. 3, projecting froiT. a circular ring, [rr,] which may be considered as its centre of motion, but perforated with a hole through the centre, large enough to contain the hair-spring within it. A circular groove is turned out in the upper plate, nearly concentric with the balance, and the ring [rr] fits into this. Both are turned rather largest at the bot¬ tom, in the manner of a dove-tail ; but the ring, being divided at the side, opposite to the lever, [z,] can be sprung up, and rendered so much smaller, as to get it into the groove ; and, being once in, the elasticity of the DESCRIPTION OF A WATCH. 207 ring expands it, so as to fill the groove completely. In this state, it may be considered as a lever, which describes a circuit round the verge, as a centre ; and the end of it points to a divided arc, engraved on the upper plate, one end of which is marked F, and the other, S, denoting that the index, or lever, [z,] is to be moved towards one or the other, to make the watch move faster or slower, as its regulation requires. The manner of its operation is thus ; the end of the lever, or index, [z,] continues within the circle, a small distance towards its centre, and, passing beneath the outer turn of the spiral spring, [ 9 ,] has two very small pins rising up from it, which include the spring between them. The actual length of the hair-spring is, therefore, to be estimated from these pins, to the place of its connexion with the verge. Now, by altering the position of the in¬ dex, this acting length can be regulated, at pleasure, to produce such vibration of the balance, as will make the watch keep true time. By shortening the length, the spring becomes more powerful, and returns the balance quicker, so that it will vibrate in less time. This is effec¬ ted by moving the index towards F. On the other hand, turning the index towards S, lengthens the spring, by which it becomes more delicate, and less powerful, re¬ turning the balance slower than before. Many watches, instead of the arc and index, have a circular curb, or regulator, which is turned by a central arbor, to which the watch-key is applied, when it is ne¬ cessary to move it. Delicate watches have jewelled pivot-holes, for the top and bottom of the verge, to diminish the friction. These jewels are diamonds, rubies, and other stones, which unite great hardness with durability. Each consists of two pieces, one of which has a cylindrical hole drilled through it, to receive the pivot, the other is a flat piece, making the rest, or stop, which forms the bottom of the hole Both stones are ground circular on the edge, and are fit¬ ted and burnished into small brass rings, which are fast¬ ened into the bearings, above and below, by two small screws, applied to each. The addition of jewels to a 208 ARTS OF METALLURGY. watch is a great advantage, as they do not tend to thicken the oil, which brass is apt to do, in consequence of the oxidation of the metal. Mr. Dent, a lecturer before the Royal Institution, ex¬ hibited to his audience, a dissected watch, showing the complicated nature of this little machine. It appears, that the number of pieces, in a complete lever watch, is nine hundred and ninety-two, and the number of separate trades, employed in manufacturing these pieces, and in putting them together, is forty-three. Works of Reference.—Cummings’s Elements of Clock and Watch Work, 4to. 1766 ; —Berthoud, Historic de la Mesure du Temps par les Horloges, 2 tom. 4to. 1802 ;— Harrison, on Clock Work and Music, 8vo. 1775 ;— Robison’s Mechanical Philosophy, article Watch Work, vol. iv. ;— Martin’s Circle of Mechanical Arts, 4to. 1818 ;—and the Encyclopedias of Brewster, Rees, and Nich¬ olson, under various heads. CHAPTER XX. ARTS OF METALLURGY. Extraction of Jletals, Assaying, Alloys. Gold, Extraction, Cupella- tion. Parting, Cementation, Alloy, Working, Gold Beating, Gilding on Metals, Gold Wire. Silver, Extraction, Working, Coining, Plat¬ ing. Copyier, Extraction, Working. .Brass, Manufacture, Buttons, Pins, Bronze. Lead, Extraction, Manufacture, Sheet Lead, Lead Pipes, Leaden Shot. Tin, Block Tin, Tin Plates, Silvering of Mir¬ rors. Iron, Smelting, Crude Iron, Casting, Malleable Iron, Forg¬ ing, Rolling and Slitting, Wire Drawing, Nail Making, Gun Ma'’iiig. Steel, Alloys of Steel, Case Hardening, Tempering, Cutlery. The term metallurgy, in its most comprehensive sen'^e, signifies the art of working metals, in every different way. In a more precise and limited sense, it is confined to the separating of metals from their ores, and assaying them, to ascertain their value. In the present chapter, it is pro¬ posed to make use of the term in its more general mean¬ ing ; so far, at least, as to comprehend certain processes EXTRACTION OF METALS. 209 in the management and manufacture of metals, which are sufficiently interesting, to merit the attention of the general student. Extraction of Metals. —Metals are found in Nature, in various states. When uncombined, or when combined only with each other, they are said to be in a native state. When combined with other substances, so that the me¬ tallic properties are, in some measure, disguised, they are said to be mineralized, or in the state of ore. The substance, with which the metal is combined, is termed its mineralizer. The most common states of combina¬ tion, in which the metallic ores are founds are oxides, combinations of oxides with carbonic, sulphuric, muriatic, and phosphoric, acids and sulphurets. These ores oc¬ cur, under various forms, sometimes crystallized, and often destitute of any regular figure. They are met wkh, gen¬ erally, in veins, penetrating the strata ; and, in this case, are usually blended, or intermixed, with various' earthy fossils, as calcareous spar, fluor spar, quartz, &c. The accompanying fossil is termed the gangue, or matrix., of the metal. Some metallic ores occur in beds, or in large insulated masses. To separate the metal, after it is dug from the mine, the mass is broken up, and subjected to the operations of sorting, stamping, washing, roasting, smelting, and re¬ fining. Sorting consists merely in the separation of the different pieces of ore, into lots, acco^ng to the products they are expected to aflbrd, and thel^reatment they are likely to require. After the ore is sorted, it is carried to the stamper, or stamping-mill, which has been described in a former chapter. The process of stamping, breaks and pounds up the ore, together with its gangue, into a coarse powder. From the stamping-mill, the pounded ore is conveyed to the icashing ; a process, in which ad¬ vantage is taken of the difference of specific gravity. The operation of washing is sometimes performed by hand, in wooden vessels, or in troughs, which cross a current of w'ater ; and, sometimes, if the ore is rich, and valuable, upon inclined tables, covered with cloth. In this pro¬ cess, the heavier parts, consisting of the metallic ore, 18 * 210 ARTS OF METALLURGY. sink first to the bottom, while the stony matter, which is lighter than the ore, being longer in sinking, is carried further down the current, and thus separated from the rest. The next operation, which is that of roasting, is em¬ ployed to drive off the sulphur, arsenic, and other volatile parts, which the mineral may contain. It is performed in a variety of ways, and by dilFerent processes, accor¬ ding to the nature of the ore, and the degree of heat re¬ quired. The roasting is sometime performed in the air, and sometimes, in furnaces, among the fuel. Smelting consists, in general, in fusing the roasted ore, with a view to extract the metal ; though the term is sometimes ap¬ plied to the melting of metal, in any state, especially iron. The immediate object of this process is to reduce the metal, or to separate the oxygen, with which the metal has either been naturally combined, or has united, during the operation of roasting. This is done, by placing in a furnace, alternate layers of charcoal, or coke, and of the metallic matter ; a strong heat is then excited by bellows ; the carbonaceous matter attracts the oxygen, while the metal is reduced, melted, and run out, at the bottom of the furnace. The volatile metals are obtained by subli¬ mation, or distillation. Even after these operations, the metal is seldom pure, but is combined with some other metal or metals, which have been present in the ore. If these are in small quantity, and do not injure the metal, they are in general disregarded. If it is necessary, how¬ ever, to separate them, or if, from their value, the sep¬ aration is an object of importance, different processes are followed, adapted to each particular metal. All the op¬ erations, subsequent to smelting, are comprehended under the general name of refining, because their eflhct is always to obtain a purer metal. The different metals are refined by different processes. Jlssaying .—The art of assaying metallic ores is that of analyzing them, in small quantities, so as to discover their component parts. It requires a knowledge of the relations of the metals to the other chemical agents, and is varied, in its different stages, as applied to each. The general process consists, in selecting proper specimens of ALLOYS. 211 the ore, which is done, by taking equal portions of that which appears to be the richest, the poorest, and of me¬ dium value, and reducing these to coarse powder, which is washed, to carry off any earthy or stony matter. It is then roasted in a shallow earthen vessel, under a muffle, to expel the volatile principles. It is lastly reduced, by mixing it with fluxes, and applying a more or less intense heat, as the metal is more or less refractory. The me¬ tallic matter, existing in the ore, is thus obtained. This, it is obvious, may consist of various metals ; and, if there is reason to believe this, and it be of importance to ascer¬ tain it, it is submitted to operations, adapted to the metals which may be supposed present. Sometimes, an accu¬ rate analysis is made, at once, of the metallic ore, in the humid way; the metal being dissolved by the different acids, and precipitated by the alkalis, earths, and other re-agents. The assaying of the precious metals is usual¬ ly confined to ascertaining the quantity of gold or silver, in any alloy or compound, without regard to the other constituents. Jllloys .—The metals are capable of combining with each other, by fusion ; and to these combinations, the name of alloy is given. They all retain the general metallic properties,—lustre, opacity, and density ; and even, in the greater number of cases, the properties of the constituent metals remain in the combination, only somewhat modi¬ fied. In general, alloys are more hard and brittle than the individual metals of which they consist, though this, as well as the other changes of properties, is considerably influenced by the proportions, in which the ingredients are combined. They have also, in general, a greater fusi¬ bility, than the mean fusibility of the respective metals. Tlie alloys of quicksilver, called amalgams^ are usually soft, or liquid, according to the proportions. The metals combined in alloys, are generally more susceptible of ox- idizement, than in their separate state ; owing, probably, to the diminution in the power of cohesion, by tlie com¬ bination, or, perhaps, to an electrical action. From their peculiar properties, some of the alloys are extensively used, as brass, which is an alloy of copper and zinc ; and pewter, which is an alloy of tin and zinc or lead. 212 ARTS OF METALLURGY. A degree of condensation usually attends these combi¬ nations, so that the specific gravity of the alloy is greater, than the mean specific gravity of its constituent metals. In brass, for example, it is one tenth greater, and, in some cases, the condensation is such, that the density is even greater than that of the heavier metals combined, as in the alloy of silver and quicksilver. Sometimes, how¬ ever, the particles assume such an arrangement, that the density is less than the mean, as in the examples of the alloy of copper with silver, and of gold with tin, and gold with iron. In these combinations, there exists a certain order of attractions, by which one metal is more disposed to unite with another, than a third is. The difference, however, is not very considerable ; hence, three, four, or more, metals can be combined together. Some, however, are difficult to unite, as iron and lead, and iron and quicksilver. The combination seems to be, in some measure, regulated by the relations of fusibility and specific gravity ; so that, the affinities being equal, the metals are less disposed to com¬ bine, as they differ more in their fusibility and specific gravity ; and, where the affinity is weak, a considerable difference of this kind may prevent any combination what¬ ever. _ GOLD. Gold exists in various minerals ; but the greatest part of the gold, in the possession of mankind, has been found in the form of grains and small masses, among the alluvial sands, which constitute certain plains, and margins of riv¬ ers. In this state, it is usually alloyed with small por¬ tions of other metals, particularly silver and copper. Extraction .—When native gold is found in a state of mixture with foreign matters, its extraction is commonly performed by amalgamation with quicksilver. After hav¬ ing been freed, by pounding and washing, from most of the stony matter mixed with it, it is triturated with ten times its weight of quicksilver, until an amalgam is formed. This is separated from any superfluous earthy matter, and subjected to pressure, enclosed in leather, by which the CUPELLATION.-PARTING. 213 more fluid part Is separated, and forced through the leath¬ er, while the more consistent amalgam, containing the greater part of the gold, remains. It is then subjected to distillation, in retorts of earthen w^are, to separate the quicksilver, and the remaining gold is afterwards fused. When the gold is contained in other ores, the ore is roasted, to drive off the more volatile principles, and to oxidize the other metals. The gold is then extracted, by amalgamation, by liquefaction with lead, by the action of nitric acid, or other methods, adapted to each ore, accor¬ ding to its constituent parts. Cupellation. —Gold, obtained in any of these ways, is always more or less alloyed, particularly with silver or copper. The first step in its purification is the process of cupellation. To explain the nature of this, it is neces¬ sary to observe, that lead is a metal very fusible, and ex¬ tremely easy of oxidizement, forming an oxide, which easi¬ ly vitrifies, and which favors the oxidizement and vitrifica¬ tion of other metals. A portion of lead, therefore, is ad¬ ded to the impure gold, more or less, according to the quantity of alloy which it contains, of which the work¬ man judges by the color, hardness, elasticity, and specific gravity, of the gold. They are melted together, and ex¬ posed to heat on a cupelj which is a vessel made of bone- ashes, or, sometimes, of wood-ashes, under a muflle, or, in the large way, on the hearth of a refining furnace. The lead passes to the state of oxide, is vitrified, and, at the same time, promotes the oxidizement and vitrification of the foreign metals. The vitrified oxide is absorbed by the porous cupel, or, in the large way, the greater part is driven off by the blast of bellows, and removed. When the greater part of the foreign metals is abstracted, the remaining fused metal exhibits various prismatic col¬ ors, which succeed each other quickly. It at length sud¬ denly brightens, and its surface becomes highly luminous. This is regarded as the completion of the process. The metal is allowed to become solid, and, while yet hot, is detached. Parting .—The gold, even after having been submitted to this process, may still be alloyed with silver, which, 214 ARTS OF METALLURGY. being nearly as. difficult of oxidizement, is not removed by the action of the lead. It is, thei’efore, lastly sub¬ jected to the operation of parting. The metal is rolled out thin, and cut into small pieces. These are digested with a moderate heat, in diluted nitric acid, which dis¬ solves the silver, leaving the gold, undissolved, in a por¬ ous mass. It has been found, however, that, when the proportion of silver is small to that of gold, the latter protects the former from the action of the acid The previous step of quartation, as it is named, is therefore employed, which consists in fusing three parts of silver with one of the gold, and then subjecting this alloyed metal, rolled out, to the operation of the acid. These are the operations employed in commerce. To obtain gold, perfectly pure, still another process is, perhaps, nec¬ essary,—dissolving it in nitro-muriatic acid, and adding to the solution, a solution of sulphate of iron, which, at¬ tracting the oxygen, precipitates the gold, in the metallic state. Cementation .—The process of cementation is per formed, by beating the alloy into thin plates, and placing these in alternate layers, with a cement, containing nitrate of potass, and sulphate of iron. The whole is then ex¬ posed to heat, until a great part of the alloying metals are removed, by the action of the nitric acid, which is liberated by the nitre. Cementation is sometimes em¬ ployed, by goldsmiths, to refine the surface of articles, in which gold is alloyed with baser metals. Jllloy .—There is a peculiar language, established in commerce, and often referred to, by writers, to denote the purity of gold, or the degree'of its alloy with other metals. The mass is supposed to consist of twenty-four equal parts, these imaginary parts being termed carats. If perfectly pure, or unalloyed, it is said to be gold twen¬ ty-four carats fine ; if alloyed with one part of any other metal, or mixture of metals, it is said to be twenty-three carats fine. In this way, the proportion of alloy is ex¬ pressed. The standard gold coin of the United States, and Great Britain, is twenty-two carats fine ; or contains one twelfth part of alloy. WORKING.-GOLD-BEATING. 21i; Gold, when perfectly pure, is not so fit for coin, on account of its softness, in consequence of which, the im¬ pression is soon obliterated, and it sustains loss from fric¬ tion. Hence, it is always alloyed, to give it hardness. The metals, that have been used for this purpose, are sil¬ ver or copper. Gold, made standard by an alloy, con¬ sisting of equal parts of silver and copper, has a color, approaching more to that of pure gold, than any other alloy. This color also remains uniform, while that with copper, after a certain degree of wear, becomes une¬ qual.* Working .—Common goldsmiths’ work is performed, by casting in moulds, beating with hammers, and rolling between polished steel rollers. Works, that have raised or embossed figures, are commonly cast in moulds, and afterwards polished ; or, they are struck in dies, cut for the purpose. Vessels, both of gold and silver, are beat out from flat plates. When the form is difficult, they are made of several plates, and soldered together. The solder used fo»»-t^iis purpose, is an alloy of gold with sil¬ ver, copper, or brass. Small ornamental works are commonly executed, by enchasing. This process is per¬ formed upon thin plates of gold, with a block and ham¬ mer. It consists, in driving in portions of the metal, on one side, in such a manner, that they stand in relief, form¬ ing the figures required, on the opposite side. Many small articles are also made from gold wire, variously wrought and ornamented. Gold Beating .—The great utility of gilding, in the arts, in furnishing an incorruptible covering to various ♦ Mr. Hatchet, with Mr. Cavendish, subjected the different alloys that have been used as coin, to friction, as similar as possible to that to which they must be subjected, in the course of circulation. The loss was by no means considerable ; and it appeared, as the general result, that the present standard of gold, or an alloy of one part in twelve, is, all circumstances considered, the best, or at least, as good as any, that could be chosen. If the copper be in larger proportions, more loss is sustained, from friction. The same alloy is employed in the fabrication of plate, and of trinkets, and lace, and, by other addi¬ tions, various shades of color are obtained. Its alloy with a fifth of silver forms the green gold of the jewellers, and the addition of iron gives a blue tint. 21G ARTS OP METALLURGY. substances, has given rise to an extensive consumption of gold-leaf, which is formed, by beating the metal to a state of extreme tenuity. The gold is first forged into plates, on an anvil, and then reduced, by passing it be¬ tween polished steel rollers, till it becomes a riband, as thin as paper. This riband is divided into small pieces, which are again beat upon an anvil, till they are about an inch square, after which, they are thoroughly annealed.* ' Two ounces of gold make one hundred and fifty of these squares. All these squares are interlaid with leaves, first of vellum, and afterwards, of ^old-beater’s skin, a thin membraneous substance obtained from the intestines of animals. The whole is then beaten with a heavy ham¬ mer, till the gold is extended to the same size as the pieces of skin. The gold leaves are then taken out, and each cut into four parts ; and the six hundred pieces, thus produced, are again interlaid, in the same manner, with skins, and the beating repeated, with a lighter ham¬ mer. They are afterwards re-divided, as before, and formed into parcels, which are separately beat, at one or more operations, until the leaf has attained the requi¬ site thinness. The use of the membranes, which are in¬ terposed between the leaves, is, to prevent them from co¬ hering together, at the same time that they are permitted to expand ; and, also, to soften the blows of the hammer. Notwithstanding the vast extent, to which gold is beaten between these skins, and the great tenuity of the skins themselves, yet they are said to sustain continual repeti¬ tions of the process, for a long time, without receiving inju¬ ry. The kind of leaf, called party-gold, is formed, by lay¬ ing a thin leaf of gold upon a thicker one of silver. They are then heated, and pressed together, till they unite and cohere ; after which, they are beaten into leaves, as before. Gilding on Jlletals. —Gilding on copper is commonly performed with an amalgam of gold and mercury. The surface of the copper, being freed from oxide, is covered * The process of annealing is applied to metals, and some other substances, to diminish their brittleness, or increase their flexibility and ductility. It is performed, by heating the substance, and suffering it to cool, in a very gradual manner. GOLD-WIRE.-SILVER,-EXTRACTION. 217 with the amalgam, and afterwards exposed to heat, till the mercury is driven off, leaving a thin coat of gold. It is also performed, by dipping a linen rag in a saturated solu¬ tion of gold, and burning it to'linder. The black pow¬ der, thus obtained, is rubbed on the metal to be gilded, with a cork dipped in salt water, till the gilding appears. Iron or steel is gilded, by applying gold-leaf to the met¬ al, after the surface has been well cleaned, and heated, until it has acquired the blue color, which, at a certain temperature, it assumes. The surface is previously bur¬ nished, and the process is repeated, when the gilding is required to be more durable. It is also performed, by di¬ luting the solution of gold in nitro-muriatic acid, with al¬ cohol, and applying it to the clean surface.* Gold Wire .—The common gold or gilt wire is, in reality, silver wire covered with gold. In making it, a silver rod is enclosed in thick leaves of gold. It is then drawn, successively, through conical holes, of different sizes, made in plates of steel, in a manner similar to that pursued in making iron wire. The wire may thus be re¬ duced to an extreme degree of fineness, the gold being drawn out with the silver, and constituting a perfect coating to the wire. When it is intended to be used in forming gold-thread, the wire is flattened, by passing it between rollers of polished steel. The coating of gold remains unbroken, though so far reduced, by these pro¬ cesses, as not to occupy the millionth part of an inch in thickness. The gold-thread, commonly used in embroi¬ dery, consists of threads of yellow silk, covered by flat¬ tened gilt wire, closely wound upon them by machinery. SILVER. Extraction .—Silver is, in general, extracted without * This last process has been improved by Mr. Stoddart. A satura¬ ted solution of gold in nitro-muriatic acid, being mixed with three times its weight of sulphuric ether, dissolves the muriate of gold, and the solution is separated from the acid beneath. To gild the steel, it is merely necessary to dip if, the surface being previously well polished and cleaned, in the etherial solution, for an instant ; and, on with¬ drawing it, to wash it instantly, by agitation in water. By this method, steel instruments are very commonly gilt. n. 10 XII 218 ARTS OP METALLURGY. much difficulty. When native, it is separated from the earthy matter, by washing, and amalgamation with mer¬ cury ; the latter being separated again, by distillation. When alloyed with antimony, or arsenic, or when mineral¬ ized, the ore is roasted, to expel these metals, with the sulphur, or other volatile principles ; and the residual mat¬ ter is fused with lead, and refined by cupellation, in a tnanner similar to that described under the head of gold ; the alloy of lead and silver being exposed to heat, on the hearth of the refining furnace, the lead being oxidized along with the foreign metals, the oxidizement and vitrifi¬ cation of which it promotes, and the vitrified oxide being, in part, absorbed, and, in part, driven off by the blast of the bellows. The appearance of a vivid incandescence, or brightening, denotes when the silver has become suffi¬ ciently pure. It retains a little gold in combination, but this does not alter its qualities ; and the quantity is seldom such, as to render its separation, by the operation of parting, an object of importance. If the ore which is wrought contain only a small por¬ tion of silver, the previous operation of eliquation is sometimes performed on it. This consists in adding a certain portion of lead to the metallic matter which re¬ mains, after roasting, and fusing the ore. This alloy is then exposed to a degree of heat, just sufficient to melt the lead, which runs out, and, from its affinity to the sil¬ ver, carries it along with it, leaving the copper, or other metals, with which the silver had been combined. The alloy of silver and lead is then subjected to the usual re¬ fining process. Working .—Silver is cast into bars, or ingots, and af¬ terwards wrought, by hammering and rolling. The bars are beaten upon anvils, being heated, from time to time, to render them more ductile. The hammering is con¬ ducted, while the heat is below redness. They are then passed between polished steel rollers, until they are re¬ duced to plates of a suitable thickness. To form uten¬ sils of different kinds, these plates are hammered' in moulds, till they acquire the proper shape. Vessels are often made in pieces, which are afterwards united by sol- COINING. 219 dering. The solder, used for silver, consists of an alloy of silver, with more than an equal part of copper or brass. Figures, which are raised upon the silver, are produced by hammering the metal upon steel dies, in which the figure is cut, or by passing it through engraved rollers. , Silver is polished, by burnishing it with steel instruments, or with hard polished stones ; and by rubbing it with the oxide of iron, called colcothar, in fine powder. Silver, in the arts, is usually alloyed with a little cop¬ per, which increases its hardness, and renders it more sonorous, without debasing its color. The standard sil¬ ver of the British coins contains eighteen pennyweights of copper, in a pound Troy of silver ; and, in the Uni¬ ted States, sixteen hundred and sixty-four grains of silver contain one hundred and seventy-nine grains of copper. Coining .—The coining of silver, and other metals, was originally performed by the hammer, in matrices, or dies, engraved for the purpose. At the present day, coins, of every description, are more commonly milled. In coining by the mill, the bars or ingots, of gold or sil¬ ver, after having been cast, are taken out of the moulds, and their surfaces cleaned. They are then flattened by rollers, and reduced to the proper thickness, to suit the species of money, about to be coined. To render the jdates more uniform, they are sometimes wire-drawn, by passing them through narrow holes, in a steel plate. The plates, whether of gold, silver, or copper, when reduced to their proper thickness, are next cut out into round pieces, called blanks, or planchets. This cutting is per¬ formed by a circular steel punch, of the size of the coin, which is driven downward, by a powerful screw, and passes through a corresponding circular hole, carrying before it the piece of metal which is punched out. The pieces, which are thus cut, are brought to the standard weight, if necessary, by filing or rasping ; and the defi¬ cient pieces, together with the corners, and pieces of the plates, left by the circles, are returned to the melter. The milling, hy which the inscription, or other impres¬ sion, is given to the edge of the coin, is performed, by rolling the coin edgewise, between two plates of steel, in 220 ARTS OF METALLURGV. the form of rulers, each of which contains half of the en¬ graved edging. One of these jDlates is fixed, and the other is movable, by a rack and pinion. The coin, being placed between them, is carried along by the motion of the rack, till it has made half a revolution, and received the whole impression on its edge. The most important part of the coining still remains to be done, and consists in stamping both sides, with the appropriate device, or figure, in relief. For this purpose, the circular piece is placed between two steel dies, upon which the figures to be impressed are sunk, or engraved, in the manner of an intaglio. The two dies are then forcibly pressed together, by the action of a powerful screw, to which is attached a heavy trans¬ verse beam, which serves the purpose of a fly, and con¬ centrates the force at the moment of the impression. The coin is now finished, and is thrown out, when the screw rises. In the coining machinery erected by Boulton and Watt, and introduced at the mint in England, the process is per¬ formed by steam-power, and both the edges and faces of the money are coined at the same time.* By means of this machinery, eight presses, attended by boys, can strike nineteen thousand pieces of money in an hour, and an exact register is kept by the machine, of the number of pieces struck. For the coining of medals, the process is nearly the same as for that of money. The principal difference consists in this, that money, having but a small relief, re¬ ceives its impressions at a single stroke of the engine ; whereas, in medals, the high relief makes several strokes necessary ; for which purpose, the piece is taken out from betw'een the dies, heated, and returned again. This process for medallions is sometimes repeated, as many as a dozen or more times, before the full impression is given them. Some medallions, in a very high relievo, are obliged to be cast in sand, and afterwards perfected by be¬ ing sent to the press. Plating .—The great value of silver, and the useful * A particular account of this machinery is given in the London Mechanic’s Magazine, vol. iii. PLATING. 221 property which it possesses, of resisting oxidation, has given rise to the art of platings in which vessels and uten¬ sils of other metals^ but, chiefly, of copper, are covered with a thin coating of silver, so as to protect them from the influence of the atmosphere. Plating is sometimes executed by heating the articles, which are to be coated, and rubbing on them portions of leaf-silver, with a steel burnisher, till it adheres. But it is performed, in a better manner, by plating solid ingots of copper, and afterwards working these into any shape desired. The ductility of the coating of silver causes it to be extended, and drawn out with the copper, so that the latter metal never appears at the surface. The copper, used in plating, is alloyed with a little brass. Great care is taken, in casting, to form the ingots sound, and free from pores, or flaws. The surface of the ingot is cleaned with a file, and a thin plate of silver is applied to one or to both sides, accord¬ ing to the article to be manufactured. A saturated so¬ lution of borax is then insinuated between the edges, the object of which is, to protect the copper from oxidation, which would otherwise prevent the silver from adhering. The ingot is then carried to the furnace, and exposed to heat, until the metals adhere to each other. Their adhe¬ sion is owing to the formation of an alloy between the silver and copper, which, being fusible at a lower tem¬ perature than either of the metals, acts as a solder, to unite them together. The ingot is then rolled into sheets, by passing it, repeatedly, between iron rollers, annealing it, from time to time, as it becomes hard and brittle. The plated sheets, which are thus obtained, are form¬ ed into articles of different kinds, by hammering them in moulds, corresponding to the intended shape. When vessels are to be made, they are formed in pieces of a convenient shape, and these are soldered together, with an alloy of silver, copper, and brass. Mouldings, and other ornamental parts, are made by hammering the met¬ al in steel dies, or rolling it between steel rollers, upon which the pattern is cut. As the edges of plated ware are most liable to be injured by wear, they are common¬ ly protected by what arc called silver edges. These are 19* 222 ARTS OF METALLURGV. formed of a shell of silver, rolled out, or hammered in dies, and having its inside filled up with a mixture of tin and lead. When finished, these edges are soldered to the vessel. The handles, feet, and solid parts, of vessels are often made in the same way. Plated baskets, and other light articles, are made from copper cylinders, cov¬ ered with silver, and afterwards drawn into wire. Plating on iron, as it is used for the buckles of har¬ nesses, and other ornaments, is executed, by first covering the iron with a coating of tin, and then applying, closely to the surface, a thin plate of silver. The union is effect¬ ed by a moderate heat, sufficient to melt the tin, and form an alloy ; and it is aided by the use of a resinous flux. COPPER. 'f' Extraction .—The various sulphurets of copper are the most abundant of its ores ; and of these, the most so is copper pyrites. The malachite, red copper ore, and others, are generally associated with these, in small quan¬ tities. Copper mines are wrought in many countries, but those of Sweden are said to furnish the purest cop¬ per of commerce. The sulphurets are the ores from which copper is usually extracted. The ore is roasted by a low heat, in a furnace, with which flues are connec¬ ted, in which the sulphur, that is volatilized, is collected. The remaining ore is then smelted, in contact with the fuel. The iron present in the ore, not being so easily reduced, or fused, as the copper, remains in the scoria, while the copper is run out. It often requires repeated fusions ; and, even after these, it may be still alloyed with portions of metals, which are not volatile, and are of easy fusion. Hence, the copper of commerce is never altogether pure, but generally contains a little lead, and a smaller portion of antimony. The carbonates of copper, reduced by fusion, in con¬ tact with the fuel, afford a purer copper, as does also the solution of sulphate of copper, which is met with in some mines, the copper being precipitated in its metallic state, by immersing iron in the solution. The precipitate, which is thus formed, is afterwards fused. WORKING.-BRASS. 223 Working. —Copper, being ductile and easily wrought, IS applied to many useful purposes. It is formed into thin sljeets, by being heated in a furnace, and subjected to pressure between iron rollers. These sheets, being both ductile and durable, are applied to a variety of uses, such as the sheathing of the bottoms of ships, the cover¬ ings of roofs and domes, the constructing of boilers and stills, of a large size, &c. Copper is also fabricated into a variety of household utensils, the use of which, however, for preparing or preserving articles of food, is by no means free from danger, on account of the oxidize- ment, to which copper is liable. It has been attempted to obviate this danger, by tinning the copper, or apply¬ ing to its surface a thin covering of tin. This method answers the purpose, as long as the coating of tin re¬ mains entire. Copper may be forged into any shape, but will not bear more than a red heat, and, of course, requires to be heat¬ ed often. The bottoms of largp boilers are frequently forged with a large hammer, worked by machinery. The bolts of copper, used for ships, and other purposes, are either made by the hammer, or cast into shapes, and lol ed. The copper cylinders, used in calico printing, are either cast solid, upon an iron axis, or are cast hollow, and fitted upon the axis. The whole is afterwards turn ed, to render the surface true. BRASS. Brass is an alloy of copper and zinc. The propor¬ tions of these two metals differ, in almost every place in which brass is manufactured ; and the proportion of zinc is found, in difierent specimens, to vary from twelve to twenty-five parts, in a hundred. The alloy is com¬ monly made from the ores of zinc mixed with copper, and with a sufficient quantity of charcoal, to reduce them to a metallic state. The volatility of the zinc gives it a tendency to escape in vapor, on which account, the combination is effected at a lower heat, than that which would be necessary to melt the copper. Several other alloys, of the same metals, are also known in tlie arts, dif- 224 ARTS OF METALLURGY. fering in the proportions of the ingredients ; such as ptneh^ beck, princess-metal, tombac. Bath-metal, &c. Manufacture .—The value of brass, in the arts, con¬ sists, in its bright color, in its being more fusible than copper, and in its being more easily wrought with com¬ mon tools. In the working of brass, the larger articles, as well as those of complicated forms, are cast in moulds. When it is intended, for economy of the metal, that the article shall be hollow, as in the case of andirons, &.c., it is cast in halves, or pieces, which are afterwards sol¬ dered together, and turned in a lathe, or otherwise pol¬ ished. Brass is also rolled into thin sheets, and drawn into wire. A variety of figured and ornamental articles are made, by stamping it in dies, or moulds. Brass knobs and similar implements, if large, are made in pieces, and soldered. The wheel-work of time-pieces, and of other machinery, which is not subjected to great strain or w'ear, is usually made of brass. The comparative softness of this alloy permits it t(^be cut with thin saws, and to be turned in a lathe, with much greater ease than iron. Buttons are either struck out of sheets of brass, with a circular punch, driven by a fly-press, or they are cast, in large numbers at once, in a mould, or flask of sanu. The eye, or shank, of the button, is made separately, by a machine, and soldered on, if the button has been cut out by the punch, if the button is cast, the eye is pre¬ viously placed in the mould, so that its extremity is im¬ mersed in the centre of the melted metal. If the button is to be plain, its surface is planished by the stroke of a smooth die ; and, if figured, it is stamped with an en¬ graved die. Tite edges are afterwards turned off, in a lathe. The gilding of brass buttons is performed, by cov¬ ering them with an amalgam of gold and mercury, fro.r. which the mercury escapes, when heated, and leaves the gold. White-metal buttons are made of an alloy of brass and tin, and subsequently coated with tin. The brass eyes of pearl buttons are inserted, by drilling a conical hole, which is largest on the inside, in the mother of pearl, or shell, of which the button is made. The eye, having an extremity like a hollow cone, is then driven in, till it spreads, and fills the cavity. PINS.-BRONZE. 225 Pins are made of brass wire, cut into proper lengths. The pieces are pointed, by turning them with the fingers, upon stones or steel mills. The heads are cut from a spiral coil of wire, in pieces of a suitable length ; and, af¬ ter being placed upon the pins, are shaped and fastened, by the stroke of an instrument like a hammer. Several machines have been invented for this manufacture, one of which makes a solid head, from the body of the pin itself. Pins are whitened, by immersing them in a vessel, con¬ taining tin and lees of wine, and are polished, by agita¬ ting them with bran, in a revolving cask. Bronze .—A series of alloys is formed, from the com¬ bination of copper with tin. The combination appears to have a tendency to form in certain proportions, regulat¬ ed, in some measure, by the specific gravities and fusibil¬ ities of the metals ; for, when kept in fusion, and allowed to cool without agitation, two alloys are formed, the under part of the mass being one of cojiper, with a small portion of tin, and the upper part tin, with a small proportion of copper, while, between these, there is, probably, a grada¬ tion. By agitation, this separation is counteracted. In general, tin lessens the ductility of copper, while it ren¬ ders it more hard, rigid, and sonorous ; these qualities being possessed, in various degrees, by the different alloys, according to their proportions ; the hardness and brittle¬ ness being greater, as the tin predominates. The densi¬ ty of the compound is, also, always greater than the mean density ; the contraction, from the combination, being about one eighth. The principal of these alloys are bronze., gun-metal, from which pieces of artillery are cast, bell- metal, and speculum-metal, which has been used for the mirrors of reflecting telescopes. Bronze is one of those, in which the proportion of tin is least, not exceeding ten or twelve parts m one hundred. It is of a grayish yellow color, harder than copper, less liable to rust, and more fusible, so as to be easily cast in moulds. Hence it is employed in the casting of statues. The metal, from which pieces of artillery are cast, is of a similar compo¬ sition, containing rather less tin. It appears that an al¬ loy, very similar to bronze, was much in use among the 226 ARTS OF METALLURGF. ancients ; and swords, darts, and other warlike instru¬ ments, were formed of it, as were also various utensils.* When the proportion of tin is increased, the alloy is rendered more brittle and elastic, and, at the same time, highly sonorous. J3ell-7netal is an alloy of this kind, in which the proportion of tin varies from one third to one fifth of the weight of the copper, according to the size of the bell, and the sound required. When the proportion of tin is still greater, an alloy is formed, called speculum-metal^ which is of a white color, and which, from the closeness of its texture, and its sus¬ ceptibility of a fine polish, exceeds most metals in the property of reflecting light. Hence it is used in forming the speculum of reflecting telescopes. It has, also, the advantage of not being liable to tarnish, on exposure to the air. The proportion in which these qualities were best attained, appeared, from the experiments of Mr. Mudge, to be a little less than one part of tin, with two parts of copper. The Chinese pakfong^ or white cop¬ per, which is sometimes imported from that country, is an alloy, according to Dr. Fyfe, of copper, zinc, nickel, and iron. The article used in this country, and in Europe, under the name of German silver^ is essentially an alloy of copper, zinc, and nickel. LEAD. Extraction. —Lead, mineralized by sulphur, forms by far the most abundant ore of the metal, and has been long known to mineralogists by the name of galena. This is the ore which is generally wrought, and from which nearly * According to Dr. Pearson’s experiments, made on various instru¬ ments of tliis kind, the alloy appears to have consisted of about eight or nine parts of copper, with one of tin ; and, as he justly remarks, this alloy still affords the best substitute for iron or steel. While the art, therefore, of manufacturing malleable iron was imperfectly known, and difficult to be practised, it must have been much used. The hard¬ ness of this alloy, observed in ancient arms, had even given rise to an opinion, that the ancients were acquainted with a method of hardening copper, which had been lost. Of this alloy, medals and coins were also often formed, as appears from the experiments of Dize, on sever¬ al Greek, Roman, and Gallic coins, which consisted of copper and tin alone. SHEET-LEAD.-LEAD PIPES. 227 all the lead of commerce is procured. The ore, after being pounded, and freed from the admixture of any stony matter, by washing, is fused in a furnace, with the addi¬ tion of lime, which combines with the sulphur of the sul- phuret ; the lead is melted, and run out by an aperture, towards the bottom of the furnace. When the native salts of lead are found with the galena, so as to render it of importance to work them, they are selected, until a suffi¬ cient quantity be obtained. They are then roasted, to expel the volatile matter, and are afterwards fused, in con¬ tact with the fuel, with an addition of lime. The lead ob¬ tained from galena, sometimes contains so much silver, as to be subjected to an additional process to separate the silver. In this case, tiie lead is oxidized in a furnace; a current of air being directed on its surface, when in fu¬ sion, by bellows. Towards the end of the operation, the silver remains, with a small portion of lead, from which it is freed, by cupellation ; and the oxide of lead is either applied to the purposes for which it is used, or is reduced to the metallic slate. Manufacture. —Lead, being fusible at a low tempera¬ ture, requires only to be cast in smooth moulds, to form weights, bullets, and other articles of small size. The linings of cisterns, and the coverings of roofs, gutters, &c., are made of sheet-lead ; pumps, and aqueducts, of leaden pipes. Sheet Lead., of the thicker kinds, is cast upon large tables, covered with sand, and having an elevated rim. The melted lead is poured upon the surface, out of a box, which moves upon rollers across the table, and is spread out with a uniform thickness, by passing over it a straight piece of wood, called a strike. The sheets, thus cast, are afterwards rendered thinner, by reducing them between rollers. The sheet-lead with which tea-chests are lined, is an alloy of lead and tin, and is made by the Chinese, by suddenly compressing the melted metal between flat, polished stones. Lead pipes., for conveying water, may be made in vari¬ ous ways. They were at first formed of sheet lead, bent round a cylindrical bar, or mandrel, and soldered ; but 223 ARTS OF METALLURGY. these pipes are liable to crack and leak, especially when bent. A second method is, to cast a short tube of lead in a cylindrical mould, with a core. This tube, when cold, is drawn nearly out of the mould, and a fresh por¬ tion of melted lead poured in, at apertures in the sides of the mould. The melted lead unites with the tube, previously formed, so as to increase its length; and by repeating the process, any length of pipe may be pro¬ duced. But pipes, cast in this manner, are found to have imperfections, arising from flaws and air bubbles. A third method, which is now most commonly practised, is to cast a short, thick tube of lead, upon one end of a long, polished, iron cylinder, or mandrel, of the size of the bore of the intended pipe. The lead is then reduced in size, and drawn out in length, either by drawing it on the mandrel, through circular holes, of different sizes, in a steel plate ; or by rolling it between contiguous rollers, which have a semi-circular groove, cut round the circum¬ ference of each. A fourth mode, invented by Mr. Bra¬ mah, consisted in forcing melted lead, by means of a pump, into one end of a mould ; while it was discharged, in the form of a pipe, at the opposite end. Care was taken, so to regulate the temperature, that the lead should chill, just before it left the mould. Leaden shot consist of drops of metal, which are dis¬ charged, in a melted slate, from small orifices, and cool in falling. The best shot are cast in high towers, built for the purpose. The lead is previously alloyed with a portion of arsenic, which increases the cohesiveness of its particles, and causes it to assume, more readily, the glob¬ ular form. It is melted, at the top of the tower, and poured into a vessel, which is perforated at bottom, with numerous small holes. The lead, after running through these perforations, immediately separates into drops, which cool, in falling through the height of the tower, and are received in a reservoir of water, at bottom, to break the force of the fall. The shot are then proved, by rolling them down an inclined board. Those which are irregular in shape roll off* at the sides, or stop, while the spherical ones continue to the end. They are then assorted, by TIN.-BLOCK TIN.-TIN PLATES. 220 passing them through wire sieves of different fineness. The glazing is given, hy agitating them with small quan¬ tities of black lead. Shot is sometimes made, mechanically, by cutting sheets of lead into cubes, and agitating these, for a long time, in a cylindrical vessel, turned upon an axis. The attrition, thus produced, communicates a globular form to the cubes. TIN. , ' Native oxide of tin, or tinstone, as it is commonly nam¬ ed, is the only ore that is wrought, to obtain this metal. Being freed, by washing, from the intermixture of any stony matter, it is roasted, and then fused, in contact with the fuel, by a moderate heat. The tin of Cornwall is supposed to be purer than the German tin, though it is still inferior to the tin from India. Block-tin, consisting of the metal in its solid state, is used for vessels which are not exposed to a temperature much exceeding that of boiling water. Vessels of this kind, being not readily tarnished, form a cheaper substi¬ tute for silver and plated ware. A kind of ware, de¬ nominated Biddery ware, consists of tin vessels, alloyed with a little copper, and having their surface made black, by the application of substances, containing nitre, com¬ mon salt, with sal ammoniac. Tin-foil is made by rol¬ ling, in the same way'as the plates for tinned iron here¬ after described. It is also sometimes hammered. The most extensive use, however, to which metallic tin is ap¬ plied, is to form a coating for other metals, which are stronger than itself, but at the same time more liable to oxidation by exposure to the air. Tin plates, which constitute the material of the com¬ mon tin ware, so extensively used, are thin sheets of iron, coated with tin. The mode of rolling these sheets will be described under the head of Iron. To prepare them for tinning, they are steeped in water, acidulated with muriatic acid, and then heated, scaled, and rolled, to re¬ move all oxide, and enable the tin to adhere to the iron. The (in is kept melted in oblong, rectangular vessels, and to preserve its surface from oxidation, a quantity of melt- II. 20 XII. 230 ARTS OF METALLURGY. ed fat and oitis kept floating upon it. The iron plates are taken up with pincers, and immersed in the tin for some time. When withdrawn, they are found to have acquired a bright coating of the tin, which adheres closely, owing to the formation of an intermediate alloy. The dipping is repeated twice, or more times, according to the thickness of the coat intended to be given, and also to produce a smooth surface, and, between these processes, the tin is equalized with a brush.* Various other articles of iron, such as spoons, nails, bridle-bits, small chains, &lc. are coated with tin, by im¬ mersing them in that metal, while in a state of fusion. From the affinity between tin and copper, a thin layer of the former metal can be easily applied to the surface of the latter ; and this practice of tinning, as it is named, is often employed, to prevent the erosion, or rusting, of copper vessels, and the noxious impregnation which they would otherwise communicate to liquors kept in them. The surface of the copper is polished, so as to be quite bright; sal-ammoniac is applied to it, when hot, by which the oxidation appears to be prevented ; or pitch is some¬ times used, for the same purpose. The melted tin, or, sometimes, an alloy of tin and lead, is then applied to the surface of the copper, to which it readily adheres. Silvering of Mirrors .—The surfaces, best adapted for reflecting light, are those of polished metals. To con¬ stitute a good reflector, it is necessary that a metal should be susceptible of an equal, unbroken, and exquisite, pol¬ ish, and that it should retain this polish, without being tarnished by the atmosphere. Speculum-metal is, chiefly, employed for reflecting surfaces, in telescopes ; but, for common purposes, an amalgam of tin and mercury is used, in a state of adhesion to glass. The use of the glass is, in the first place, to produce a smooth surface, in the amalgam ; and, afterwards, to protect it from oxidation by the atmosphere. In the silvering of plain looking-glasses, a flat, hori- * For a full account of the present mode of manufacturing tin plate, Me Parkes’s Chemical Essavs, vol. ii. IRON. 231 zontal slab of stone is used, as a table. This is smoothly covered with paper, and a sheet of tin-foil, equal to the size of the glass, is extended over it. A quantity of mercury is then laid upon the tin-foil, and immediately spread over it, with a roll of cloth, or a hare’s foot. Af¬ terwards, as much mercury, as the surface will hold, is poured on. While this mercury is yet in a fluid state, the plate of glass is slid on, at the edge of the table, so as to pass over the tin-foil, driving the superfluous mercury before it. In this way, any bubbles of air and particles of dust are prevented from getting between the glass and the metal, and an uninterrupted coating is formed. In order to force out the remaining liquid mercury, the glass is placed in a sloping position, to allow the mercury to drain off, after wJiich, heavy weights are placed upon the glass, and suffered to remain, for some time. The por¬ tion, which is left, amalgamates with the tin, and forms a permanent reflecting surface, the smoothness and perfec¬ tion of which depend upon the degree of regularity and polish, W’hich the glass possesses. In silvering concave and convex mirrors, instead of a stone table, the tin-foil is spread upon a plaster mould, previously cast on the surface of the glass itself. The inside of glass globes is silvered, by pouring into them a fusible alloy of tin, lead, bismuth, and mercury, the heat of which, when liquid, is not sufficient to break the glass. By turning the globe about, a thin metallic coating is de- . posited on the whole interior surface. IRON. The properties which iron possesses, in its various forms, render it the most useful of all the metals. The toughness of malleable iron adapts it to purposes, where great strength is required ; while its combination of diffi¬ cult fusibility with the property of softening by heat, so as to admit of forging and welding, renders it capable of being easily worked, and of withstanding an intense heat. Cast-iron, from its cheapness, and the facility with which its form is changed by fusion, is made the material of numerous structures and machines. Steel, which is the 232 ARTS OF METALLURGY. most important compound of iron, exceeds all other me¬ tals, in the combination of hardness and tenacity ; and hence, it is particularly adapted to the fabrication of cut¬ ting instruments. It is equally superior in elasticity, a quality by which it is suited to be the spring of motion, in various machines. Smelting .—The principal ores, which are wrought for the extraction of iron, are the different species of the na¬ tive oxides. The process is somewhat different, as car¬ ried on, in different countries, and as adapted to different ores ; but the following is the general outline of it, as it is conducted on the haematite bog-ores, and other oxides of iron. The blast-furnace, in which the operation is conducted, is a large pyramidal stack, made of bt-ick or hewn stone, from twenty to sixty feet high, having its internal cavity shaped like an egg, with its large end downwards, and lined with fire-brick or stone. The ore is first roasted, with a strong heat, to expel the carbonic acid, and any portion of sulphur, or other volatile matter, that may be present. The remaining ore is put into a furnace, of a conical form, with charcoal, or with coke, and exposed to a heat, rendered sufficiently intense by a blast of air, urged through the furnace. A quantity of lime is, at the same time, added to the ore and fuel; the advantage of which appears to be, that in combination with the argillaceous and silicious substances, generally contained in the iron ores, it acts as a flux, to vitrify the foreign matter, and thus facilitate the separation of the melted metal. The proportions of these are ex¬ tremely various, according to the nature of the ore. When the furnace is once charged, the charge is renewed at the upper part, as fast as the materials sink, and the pro¬ cess is carried on, for a long time, without interruption. During this process, the oxygen of the oxide of iron unites with one portion of the carbon, and the metal with anoth¬ er, producing carbonic acid, and carburet of iron ; while the earthy substances, together with a little oxide of iron, enter into combination, forming a vitreous substance call¬ ed slag, or scoria, and which, being lighter than the me- CRUDE IRON.-CASTING. 233 tal, rises upon its surface. The slag is drawn off, by an opening, and the melted metal is collected in a cavity, at bottom, from which, as it accumulates, it is conveyed off, at intervals, into moulds. A vast improvement, in regard to the saving of fuel, has been produced, in late years, by the introduction of the hot blasts in smelting furnaces. The fire, in this case, is blown by air, previously heated ; the combustion be¬ comes more effective ; and a saving of two thirds of the fuel is said to be produced. Crude Iron .—The metal thus obtained, is named pig- iron.^ and crude, or cast-iron. It is far from being pure, containing, always, more or less oxygen and carbon ; and, often, several other heterogeneous ingredients, such as manganese, and the metallic bases of lime, clay, and silex, with portions of unreduced ore and charcoal. The oxy¬ gen is, partly, a portion of what was originally combined with the metal, in the ore, and partly, perhaps, derived from the blast of air, which is driven through the furnace, and necessarily presented to the metal, in a state of fusion Hence, the qualities of cast-iron are very various, accord ing as one or other of the principles predominates. Iron, in this state, is readily capable of being fused, and cast into moulds. It is, however, much more brittle, than when pure, and cannot be wrought or flattened, un¬ der the hammer. Hence, it is altogether unfit for many purposes, to which pure or malleable iron is, from its te¬ nacity and softness, well adapted. Casting. —Iron, as well as brass, and other metals, which melt at temperatures above ignition, is cast in moulds, made of sand. The kind of sand, most employ¬ ed, is loam, which possesses a sufficient portion of argil¬ laceous matter, to render it moderately cohesive, when damp. The mould is formed, by burying in the sand, a wooden pattern, having exactly the shape of the article to be cast. The sand is most commonly enclosed in flasks, which are square frames, resembling wooden box¬ es, open at top and bottom. If the pattern be of such form, that it can be lifted out of the sand, without derang¬ ing the form of the mould, it is only necessary to make 20 * 234 ARTS OF METALLURGY. an impression of the pattern, in one flask ; and articles of this kind are sometimes cast in the open sand, upon the floor of the foundry. But when the shape is such, that the pattern could not be extracted, without breaking the mould, two flasks are necessary, having half the mould formed in each. The first flask is filled with sand, by ramming it close, and is smoothed off, at the top. The pattern is separated into halves, one half being imbedded in this flask. A quantity of white sand, or burnt sand, is sprinkled over the surface, to prevent the two flasks from cohering. The second flask is then placed upon the top of the first, having pins to guide it. The other half of the pattern is put in its place, and the flask is filled with sand, which, of course, receives the impression of the remaining half of the pattern, on its under side. After one or more holes are made in the top, to permit the met¬ al to be poured in, and the steam and air to escape, the flasks are separated, and the pattern withdrawn. When the flasks are again united, a perfect cavity, or mould, is formed, into which the melted metal is poured. The arrangement of the mould is, of course, varied, for different articles. When the form of the article is complex and difficult, as in some hollow vessels, crooked pipes, &c., the pattern is made in three or more pieces, which are put together, to form the moulds, and after¬ wards taken apart, to extract them. In some other ir¬ regular articles, as andirons, one part is cast first, and afterwards inserted in the flask which is to form the other part. The metal for small articles is usually dipped up, with - iron ladles coated with clay, and poured into the moulds. In large articles, such as cannon, the mould is formed in a pit, dug in the earth, near the furnace, and the melted metal is conveyed to it, in a continued stream, through a channel communicating with the bottom of the furnace. Cannon balls are sometimes cast in moulds, made of iron ; and to prevent the melted metal from adhering, the inside of the mould is covered with powder of black lead. Rollers for flattening iron are also cast in iron cases. This method is called chill-castings and has, for its ob MALLEABLE IRON.-FORGING. 235 ject, the hardening of the surface of the metal, by the sudden reduction of temperature, which takes place in consequence of the superior conducting power of the iron mould. These rollers are afterwards turned smooth, in a powerful lathe, which has a slow motion, that the cutting topi may not become heated by the friction. .j^jg^Ialleable Iron .—To obtain pure iron, that is, to free crude iron from the oxygen, carbon, and other foreign substances, contained in it, it is subjected to two opera¬ tions,—melting, and forging. The fusion is performed in difl'erent furnaces. The melted metal is, in some cases, run out, to free it from the scoria winch has separated ; and this process is repeated, until tbe iron attains a degree of consistence, sufficient to be submitted to the action of the forge-hammer. But, more commonly, the metal is kept in fusion, in a reverberatory furnace, called a pud¬ dling-furnace, where it is raised to a very high tempera¬ ture. The liquid is stirred frequently, to facilitate the combination of the carbon and oxygen. At length, a lambent blue flame appears on its surface, probably from the formation and disengagement of carbonic oxide ; and, after some time, the fluidity of the metal diminishes, until it, at length, assumes the consistence of a stift' paste. It IS then suDjected to the action of a very large hammer, or to the more equable pressure of rollers, by which a portion of oxide of iron, carbon, and other heterogeneous substances, not consumed during the fusion, are forced out. The iron, in this state, is no longer granular in its texture, but is soft, ductile, and malleable, and much less fusible. It is then named wrought-iron, forged, or bar- iron, as it is generally formed into long bars. A consid¬ erable loss of weight attends the process, from tbe dissi¬ pation of the foreign substances, contained in the crude iron, and from the oxidation of the surface of the metal. The operation is generally performed on the varieties called white, or gray, crude iron. Forging .—Forging consists in changing the form of iron, and other malleable metals, by percussion, applied to them, while they are softened by heat. Iron, when exposed to the action of great heat, becomes highly inal- 236 ARTS OF METALLURGY. leable and ductile. It is also capable of welding, at a sufficiently high temperature. Most other metals have their malleability improved, by a certain degree of heat, but become brittle, if the heat is carried near to then* fu¬ sing point. The strength and quality of iron, on the contrary, are improved, by forging at a strong white heat, since the parts become consolidated, and the flaws oblit erated, by hammering, at a welding temperature. The joint action of the heat and current of air, used ii forges, tends to oxidate, rapidly, the surface of iron. Tlh oxide which is formed has some tendency to vitrification when combined with silicious matter. Hence it is a com mon practice among workmen, to immerse the iron in sand, when it is near to a welding heat. A vitreous coating is, by this means, formed, which protects the surface of th • iron from further oxidation. This coating would prevent the different pieces from uniting, by welding, were it not that its fluidity causes it to escape, while under the action of the hammer. The forging, at the furnaces, of large masses of iron, called blooms^ is performed by the aid of tilt-hammers, as is also that of anchors, and various other massive imple- ments,'and parts of machines. Bars of iron are common¬ ly rolled, and when heavier articles, such as anchors, are to be made, a sufficient number of bars, for the purpose, are welded together. A tilt-hammer, of the kind used in iron-works, is sho’vvn in PI. III., Fig. 2. AB, is the hammer, which turns upon the fulcrum, C. At D, is a wheel, or cylinder, furnished with wipers, [abc, &c.,] each of which, as it passes, strikes the end. A, of the helve, and causes the hammer-end, B, to rise. The hammer then descmds, tvith its own weight, and is accelerated by the recoil of the end. A, from the fixed obstacle, E. The wipers may be indefinitely varied, in number and position, and are sometimes applied, on the other side of the fulcrum. The recoil, likewise, is sometimes produced by a spring, placed over the end, B, of the hammer. The motion of these engines is extremely rapid, and is commonly reg¬ ulated by a fly-wheel. ROLLING AND SLITTING. 237 Rolling and Slitting .—Malleable iron is commonly wrought into those shapes which have flat, parallel sur¬ faces, by submitting it to compression, between rollers. Bars, plates, and sheets, of iron are formed, in tins way. A pair of heavy cylindrical rollers, made of iron, chill- cast, and turned smooth, are connected together by strong iron bearings, a space being left between them, equal to the intended thickness of the metal, which is to be rolled. This distance is varied, by adjusting it with powerful screws. The iron, which is to be rolled, is prej)ared, by heating it red hot, and, in this state, it is presented to the rollers. As soon as any part has entered, so as to fill the space between the rollers, the friction, or adhesion, becomes suflicient to draw in the remainder, in opposition to the force with which the metal resists compression. The iron, in passing through, is compressed into a uni¬ form plate, of equal thickness, and is, at the same time, extended in length, but is very little increased in breadth. As the rollers usually move with considerable velocity, the heated iron may be passed, several times, between different pairs of rollers, before it cools. To prevent the rollers from becoming heated, a continual stream of water is let fall upon their surface. As the principal extension, which plates receive, is in a longitudinal direction, it is necessary to vary their po¬ sition, when it is desired to increase their width. This is sometimes done, by passing them in an oblique direction ; but, in making sheet-iron and wide plates, it is necessary to pass the pieces through the rollers, in the direction of their breadth, as well as length, that they may be extend¬ ed in both directions. Very thin plates, like those used for tinned iron, are repeatedly doubled, and passed be¬ tween the rollers, so that, in the thinnest plates, sixteen thicknesses are rolled, together, care being taken to change their relative positions, and to interpose oil, to prevent them from cohering. The last rollings are performed, while the metal is cold. Bars which are square, round, and of various other shapes, are formed, between rollers which have grooves cut upon their circumferences, cor¬ responding, in shape, to half the bar to be made. Even 238 ARTS OF METALLURGY. rails of malleable iron, for rail-roads, have lately been made between rollers, formed for the purpose. And, at some furnaces, where malleable iron is made, the forge- hammer is dispensed with, and reliance is placed on the rollers, alone, to consolidate and equalize the masses of metal. Slitting rollers, or those intended for dividing plates of iron into narrow rods, are formed with elevated rings upon their circumferences, which reciprocally enter be¬ tween each other, their edges being angular, and passing in close contact with each other, so as to cut like shears. These rings are separately made, so that they can be re¬ moved from the rollers, for the purpose of sharpening them, when necessary. Wire Drawing .—The manufacture of wire consists, in drawing a piece of metal through a conical hole in a steel plate, which forms it into a regular cylindrical fila¬ ment. The size of this filament may be reduced, and the length extended, indefinitely, by passing it through successive holes, which gradually diminish in diameter. To prepare the iron for drawing, it is first subjected to the action of the hammer, till it is reduced to a size that will admit of its being drawn through the plate. Some¬ times, the iron is prepared by rolling; but the best wire is produced, when the metal has been thoroughly hammered. The rod of iron which has been prepared, in this man¬ ner, is next drawn through one of the larger boles in the steel plate. Various machines are employed, to over¬ come the resistance which the plate opposes to the com¬ pression and passage of the wire. In general, the end of the wire is held by pincers, and as fast as the wire is drawn through the plate, it is wound upon a roller, by the action of a wheel and axle, or other power. Sometimes, a rack and pinion is employed, for this purpose, and sometimes, a lever, which acts at intervals, and takes fresh hold of the wire, each time that the force is applied. The finer kinds of wire are made from the larger, by repeated drawings, each of which is performed through a smaller hole than the preceding. As the metal becomes stiff and hard, by the repetition of this process, it is nec- NAIL-MAKING.—GUN-MAKING. 239 essary to anneal it, from time to time, to restore its duc¬ tility. It is also occasionally immersed in an acid liquid, to loosen the superficial oxide wliich is formed, in the process.xif annealing. J^ail J\Iaking .—Nails are made, both by hand, and by machinery. Wrought-nails are made, singly, at the forge and anvil, by workmen who acquire, from practice, great despatch in the operation. IMachines have been made, for making these nails perfectly, and with rapidi¬ ty ; yet they have not come into general use, owing to the cheapness of the product by manual labor. Cut- nails are made, almost wholly, by machinery, invented in this country. The iron, after having been rolled, and slit into rods, is flattened into plates, of the thickness in¬ tended for the nails, by a second rolling. The end of this plate is then presented to the nail-machine, by a work¬ man, who turns the plate over, once, for every nail. The machine has a rapid reciprocating motion, and cuts oif, at every stroke, a wedge-shaped piece of iron, constitu¬ ting a nail without a head. This is immediately caught, near its largest end, and compressed between gripes. At the same time a strong force is applied to a die, at the extremity, which spreads the iron, sufficiently to form a head to the nail. Some nails are made of cast-iron, but these are always brittle, unless afterwards converted into malleable iron, by the requisite process. Gun Jllaking. —Cannon, carronades, &c., whether of iron or brass, are cast in sand, and afterwards bored. Muskets and fowling-pieces are forged from bars of mal¬ leable iron. The bar is first flattened by hammering, till it attains the requisite width. It is then made into a tube, by turning it over a mandrel, or cylindrical rod, of a size which is smaller than that of the intended bore. The edges are made to overlap each other, about half an inch, and are firmly welded together. The whole is then consolidated and strengthened, by hammering it, for some time, in semi-circular grooves, on a swage, or anvil, which is farrowed for the purpose. To render the barrel smooth, on the inside, and perfectly true, it is afterwards bored out, with an instrument somewhat larger than the man 240 ARTS OF METALLURGY. drel ; and several such instruments, of different sizes, are employed, in succession. The breech of the barrel is closed, by a strong plug, which is firmly screwed in, at the extremity. The projecting parts of the barrel, such as the sight., and the loops which confine it to the stock, are soldered on. The construction of the lock, and oth¬ er appendages, is readily understood, from inspection. Steel .—When malleable iron is re-combined with car¬ bon, in a much smaller proportion, it forms steel. Differ¬ ent methods are followed, to form this combination. The product varies, according to the method pursued, and is also effected, by the introduction of other'substances into the combination. The best steel is made from Swedish and Russian iron. The general method of forming steel is, by the process of cementation. A furnace is constructed, of a conical form, in which are two large cases, or troughs, of fire¬ brick, capable of holding some tons of iron. Beneath these, is a long grate, on which the fuel is placed. On the bottom of the case, is placed a layer of charcoal dust; over this, a layer of bars of malleable iron ; over this, again, a layer of charcoal powder ; and the series of alternate layers of charcoal and iron is thus raised to a considerable height. The whole is covered with clay, to exclude the air ; and flues are carried through the pile from the furnace, so as to communicate the heat more completely and equally. The fire is kept up, for eight or ten days. The progress of the cementation is dis¬ covered, by withdrawing a bar, called the test-bar, from an aperture in the side. When the conversion of iron into steel appears to be complete, the fire is extinguished ; the whole is left to cool, for six or eight days longer, and is then removed. The iron, prepared in this manner, is named blistered- steel, from the blisters which appear on its surface. To render it more perfect, it is subjected to the action of the hammer, in nearly the same manner which is practised with forged iron ; it is beat very thin, and is thus ren- ered more firm in its texture, 'and more convenient in its form. In this state it is often called tilted-steel. When ALLOYS OF STEEL. 241 the bars are exposed to heat, in a furnace sufficient to soften them, and afterwards doubled, drawn out, and welded, the product is called shear-steel. Cast-steel is made, by fusing bars of common blistered-steel, with a flux of carbonaceous and vitreous substances, in a large crucible, placed in a wind-furnace. When the fusion is complete, it Is cast into small bars, or ingots. Cast-steel is harder and more elastic, has a closer texture, and re¬ ceives a higher polish, than common steel. It is capable of still further improvement, by being subjected to the action of the hammer.* Steel is generally prepared from malleable iron. It can also be formed from crude cast-iron, as in Mr. Lucas’s method, hereafter described. Several varieties of cast- iron have been used for this purpose. The crude iron from certain ores, as the sparry iron ore, is capable of this conversion. Tlie steel, thus obtained, is named natural steely but is inferior to that obtained by cementation. ' Alloys of Steel. —Messrs. Stodart and Faraday have succeeded in making some useful alloys of steel with oth¬ er metals.f Their experiments induced them to believe, that the celebrated Indian steel, called wootz^ is an alloy of steel with small quantities of silicium and aluminum ; and they succeeded in preparing a similar compound, possessed of all the properties of tcootz. They ascer¬ tained that silver combines with steel, forming an alloy, which, although it contains only one five hundredth of its weight of silver, is superior to wootz, or to the best cast- steel, in hardness. Tlie alloy of steel with one hundredth part of platinum, though less hard than that with silver, possesses a greater degree of toughness, and is, there¬ fore, highly valuable, when tenacity, as well as hardness, is required. The alloy of steel with rhodium even ex- * Writers differ, ia regard to tire proportion of carbon contained in cast-steel. Mr. Buttery, in Ure’s Dictionary, states, that the amount is less than in common steel, and that no charcoal is added, in making it. lie also states, that it does not melt, at a welding temperature, but falls to pieces, like sand, under the hammer, and the parts refuse to become again united. t Philosophical Transactions, for 1822. 11. 21 Xll. 242 ARTS OF METALLURGY. ceeds the two former, in hardness. The compound of steel with palladium, and of steel with iridium and osmi¬ um, is likewise exceedingly hard ; but these alloys cannot be applied to useful purposes, owing to the rarity of the metals of which they are composed. M. Berthier has also produced a useful alloy, by combining with the steel a small portion of chromium. Case Hardening .—The process of case-hardening con¬ sists in converting the surface of iron into steel, and is used for giving a superficial hardness to various instruments. It is effected, by enclosing the article which is to be case- hardened, in a box, with some carbonaceous substance, usually animal charcoal, and exposing it to heat, until the surface is converted into steel. The same term is some¬ times improperly applied to the method of chill-casting, which has been already mentioned. p Tempering .—The most remarkable, as well as the most useful, of the properties of steel is the power which it has of changing, permanently, its degree of hardness, by undergoing certain changes of temperature. No other metal, says Thenard, is knowm to possess this property, and iron itself acquires it, only when it is combined with a minute portion of carbon. If steel is heated to redness, and suddenly plunged in cold water, it is found to become extremely hard, but, at the same time, it is too brittle for use. On the other hand, if it be suffered to cool very gradually, it becomes more soft and ductile, but is defi¬ cient in strength. The process of tempering is intended to give to steel instruments a quality, intermediate between brittleness and ductility, which shall insure them the proper degree of strength, under the uses to which they are ex¬ posed. For this purpose, after the steel has been suffi¬ ciently hardened., it is partially softened, or let down to the proper temper, by heating it again, in a less degree, or to a particular temperature, suited to the degree of hardness required; after which, it is again plunged in cold water. Different methods have been pursued, for determining the temperature, proper for giving the requisite temper to different instruments. One method is, to observe the shades of color which appear on the surface of the steel. TEMPERING. 243 and succeed each other, as the temperature increases. Thus, at four hundred and thirty degrees of Fahrenheit, the color is pale, and but slightly inclining to yellow. This is the temperature at which lancets are tempered. At four hundred and fifty degrees, a pale straw-color appears, which is found suitable for the best razors and surgical in¬ struments. At four hundred and seventy degrees, a full yellow is produced, suitable for penkives, common razors, &LC. At four hundred and ninety degrees, a brown color appears, which is used to temper shears, scissors, garden- hoes, and chisels intended for cutting cold iron. At five hundred and ten degrees, the brown becomes dappled with purple spots, which show the proper heat for tem¬ pering axes, common chisels, plane-irons, &.c. At five hundred and thirty degrees, a purple color is established ; and, at this degree, the temper is given to table-knives and large shears. At five hundred and fifty degrees, a bright blue appears, used for swords and watch-springs. At five hundred and sixty degrees, the color is a full blue, and is used for fine saws, augers, &c. At six hundred degrees, a dark blue, approaching to black, has become settled, and is attended with the softest of all the grades of temper, used only for the larger kinds of saws. Another method of giving the requisite temper has been practised upon various articles. The pieces of steel are covered with oil or tallow, or put into a vessel containing either of these ingredients, and heated over a moderate fire. The appearance of the smoke, from the oil or tallow, indicates the degree of heat. Jf the smoke just appear, the temi)er corresponds with that indicated by the straw-color, when the metal is heated alone. If so much heat is applied, that a black smoke arises, this points out a different degree of hardness ; and so on, till the vapor catches flame. By this method, a number of pieces may be done, at once, with comparatively little trouble, and the heat is also more equally applied. A still more accurate method of producing any desired degree of temper is, to immerse the steel in some fluid medium, the temperature of which is kept regulated, by the thermometer. Thus oil, which boils at about six 244 ARTS OF METALLURGY. hundred degrees, may be used, for this purpose, at any degree of heat which is below that number of degrees. Mr. Parkes has recommended the employment of metal¬ lic baths, chiefly composed of lead and tin, in different proportions, which pass into fusion, at definite tempera¬ tures, and which can be used for tempering steel, as soon as they arrive at their melting points.* f * The following table of metallic baths is given, in Parkes’s Chem¬ ical Essays, Appendix to vol. ii. No. Edge Tools to be tempered in the various Composition Temper. Baths. of the Bath. Faliren. 1 Lancets, in a bath, composed of 7 lead 4 tin 420'' 2 Other surgical instruments. n lead 4 tin 430 3 Razors, &c.. 8 lead 4 tin 442 4 Penknives, and some implements of surgery. lead 4 tin 450 5 Larger penknives, scalpels, &c.. 10 lead 4 tin 470 6 Scissors, shears, garden-hoes, cold chisels, &c.. 14 lead 4 tin 490 7 Axes, firmer chisels, plane-irons. pocket-knives, &c.. 19 lead 4 tin 509 8 Table-knives, large shears, &c.. SO lead 4 tin 530 9 Swords, watch-springs, &c.. 48 lead 4 tin 550- 10 Large springs, daggers, augers, small fine saws, &c.. 50 lead 2 tin 558 11 Pit-saws, hand-saws, and some par¬ ticular springs. Boiling linseed oil 600 12 Articles which require to be still somewhat softer. Melting lead 612 t Formerly, no man in Great Britain knew how to temper a sword in such a way, that it would bend, for the point to touch the heel and spring back again uninjured, except one Andrew Ferrara, who resided in the Highlands of Scotland. The demand which this man had for his swords was so great, that he employed workmen to forge them, and spent all his own time in tempering them ; and found it necessary, even in the day time, to work in a dark cellar, that he might be better able to observe the progress of the heat, and that the darkness of his workshop might favor him in the nicety of the operation. The swords, which were formerly in the highest repute, were made at Damascus, in Syria. The method, by which these were made, has long been lost, or perhaps it was never thoroughly known to Europe¬ ans ; but from their striated appearance, it has been supposed that they were formed by alternate layers of extremely thin plates of iron and steel, bound together with iron wire, and then firmly cemented together by welding. These weapons never broke, even in the hard¬ est conflict, and retained so powerful an edge, as to be capable of cut¬ ting through armor. Various other explanations have been given in regard to the character and structure of the Damascus, or damasked, steel. CUTLERY. 245 ' Cutlery .—Under the head of cutlery, are comprehend¬ ed numerous instruments, designed for cutting or penetra¬ tion, and which are made of steel, mostly, by the proces¬ ses of forging, tempering, grinding, and polishing. The inferior kinds of cutlery are made of blistered-steel, weld¬ ed to iron. Tools of a better quality are manufactured from shear-steel, while the sharpest and most delicate in¬ struments are formed of cast-steel. The first part of the process consists in forging, and is varied, according to the kind of article to be formed. Common table-knives.) have the blade forged of steel, and welded to a piece of iron, out of which the shoulder, and part which enters the handle, are made, the shape being given to them by hammering in a die and swage. They are afterwards tempered and ground. Forks are made by forging the shank, and flattening the other end to the length intended for the prongs. The prongs are made, by stamping the metal, at a white heat, between two dies, the uppermost of which is attached to a heavy weight, and falls from a height. The shape is thus given to the fork, leaving, however, a flat thin piece of metal between the prongs, which is afterwards cut out with a fly-press. They are subsequently filed, bent, hardened, and pol¬ ished. Blades of penknives are forged from the end of a rod of steel, and cut off, together with metal enough to form the joint. The small recess, in which the nail is insert¬ ed, to open the knife, is made with a curved chisel, while the steel is hot. Razors are forged from cast-steel, much in the same manner as knives. The anvil is com¬ monly a little rounded, at the sides, for the purpose of making the sides of the razor a little concave, and the edge thinner. In forging scissors^ the shape is given to the different parts, by hammering them upon different in¬ dented surfaces, called bosses. The bows which receive the finger and thumb are made, by punching a hole in the metal, and enlarging it, by hammering it round a tool, called a beak iron. Tlie halves are finished by filing and grinding, and afterwards united l)y a joint. Saws are made from steel-plates, rolled for the purpose, and have 21 * 246 ARTS OF METALLURGY. their teeth cut and finished by filing, and set by a suita¬ ble instrument. Axes, adzes, and other large tools, are forged from iron, and have a steel piece welded on, of the proper size, to form the edge. To enable the steel to be wrought, it is brought to its softest state ; but after the shape is given to the instrument, the steel is hardened and tempered, by the methods al¬ ready described. The remaining part of the manufacture consists in grinding, polishing, and setting the instrument, to produce a smooth surface and a sharp edge. The grinding is performed upon stones, of various kinds, among which, freestone is, perhaps, the most common. These stones are made to revolve by machinery, and move with prodigious velocity, so that the surface, in some cases, passes over six or seven hundred feet, in a second, and stones have been burst by their own centri¬ fugal force. For grinding flat surfaces, like those of saws, the largest stones are used ; while, for concave surfaces, like the sides of razors, smaller stones are used, on account of their greater convexity. The internal sur¬ faces of scissors, forks, &c., which cannot be applied to the stone, are ground w'ith sand and emery, applied with instruments of wood, leather, and other elastic substan¬ ces. The last polish is given by the impure oxide of iron, called colcothar-crocus, and by the French, Rouge d’ Angleterre. The edges are lastly set with hones and whetstones, according to the degree of keenness required. The test, used by cutlers, for determining the goodness of the edge and point of a lancet, is, that it shall pass through a piece of soft leather, without sensible resis¬ tance. J^eedles are polished, by tying them in large bun¬ dles, with emery and oil, and rolling them under a heavy plank, till they become smooth, by mutual attrition. The shape is previously given, and the eye made with a steel punch. A process has been invented by Mr. Lucas, for con¬ verting edge-tools, nails, &c., made of cast-iron, into good steel. It consists in stratifying the cast articles, in cylindrical metallic vessels, with native oxide of iron, and then submitting the whole to a regular heat,- in a fur- ARTS OF VITRIFICATION. ' 247 nace built for the purpose. It is not, however, necessary that the oxide employed should be a native oxide, any artificial oxide being equally effectual. The cast-iron, of which this cutlery is made, is brittle, in the first instance, like other cast-iron, in consequence of the carbon contained in it ; but the great heat which it undergoes, aided by the pulverized oxide, separates a part of the carbon. This, uniting with the oxygen of the ground oxide of iron, is dissipated in the state either of carbonic oxide, or carbonic acid gas, and the articles are then converted into a state nearly similar to that of good cast-steel cutlery. They do not, however, receive so fine an edge, and do not bear hardening and tempering, in the common manner. Works of Reference.—Murray’s System of Chemistry, 4 vols. 8vo. 1806 ; —Parkes’s Chemical Essays, 2 vols. 8vo. 1823 ;— Cray’s Operative Chemist, 8vo. 1828 ; —Dumas, Traite de Chimie Appliquee aux Arts, ^c., 4 tom. 8vo. 1828-9 ; —Fourcroy, Sys- teme des Connaissances Chimiques, 11 tom. 1801 ;— Aiken’s Dic¬ tionary of Chemistry and Mineralogy, 2 vols. 4to. 1807 ;— Martin’s Circle of Mechanic Arts, 4to. 1818 ;—Emporium of Arts and Scien¬ ces, Philadelphia, 1812-14 ; Franklin Journal, Philadelphia, 1826, and after;.— Rees’ Cyclopedia, various heads;— Ure’s Dictionary of Chemistry ;— Thenard, Traite de Chimie, 5 tom. 8vo. 1824 ;— Works of Bergman, Klaproth, Lewis, &c. ; — Lardner’s Cabinet Cyclopedia, 3 vols. 12 mo. entitled. Manufactures in Metal I - CHAPTER. XXI. ARTS OF VITRIFICATION. Glass, Materials, Crown Glass, Fritting, Melting, Blowing, Annealing, Broad Glass, Flint Glass, Bottle Glass, Cylinder Glass, Plate Glass, Moulding, Pressing, Cutting, Stained Glass, Enamelling, Artificial Gems, Devitrification, Reaumur’s Porcelain, Crystallo-Ceramie, Glass Thread, Remarks. A GREAT number of earths, and other mineral bodies, after being fused, do not resume tlieir original character, upon cooling, but pass into a dense, hard, shining, and 248 ARTS OF VITRIFICATION. brittle, state, having the character of glass ; and are thus said to be vitrified. Most of these substances do not immediately become hard, upon the reduction of their temperature, but go through an intermediate, or ductile, state, in which a combination of softness with tenacity, en¬ ables them to be wrought into articles of use and orna¬ ment. Of these, common glass is the most important, while enamels, artificial gems, &c., belong to the same species of manufacture. Glass .—Glass is a compound substance, artificially produced, by the combination of silicious earth with al¬ kalies, and, in some cases, with other metallic oxides. These substances, being melted together at a high tem¬ perature, unite, lose their opacity, and are fused into a homogeneous mass, which, on cooling, has the properties of hardness, transparency, and brittleness. tMaterials .*—The most important ingredient, and, in fact, the basis, of transparent glass, is silica, or oxide of silicium. This earth, nearly in a state of purity, is found in the sand of certain situations, and also in common flint, and quartz pebbles. Sand has the advantage of being already in a state of minute division, not requiring to be pulverized. Pure silicious sand, proper for the glass fur¬ nace, is found in many localities. A great portion of that used in the United States is taken from the banks of the Delaware. When flints, or quartz, are employed, they must be first reduced to powder, which is done by heating them red hot, and plunging them in cold water. This causes them to whiten and fall to pieces; after which, they are ground and sifted, before they are ready for the furnace. An alkaline substance, either potash or soda, is the second ingredient in glass. For the finer kinds of glass, pure pearlash is used, or soda, procured by decomposing * The term metals, which appears to be a corruption of materials, is in common use, among glass-manufacturers, to express the ingredi¬ ents, or substances, upon which their operations are performed. The same term is employed, in a similar sense, by other manufacturers and artists, and by some writers on road-making. The term metal, in the singular, is applied to glass, in a state of fusion. CROWN-GLASS. 249 sea-salt; but, for the inferior sorts, impure alkalies, and even wood-ashes, are made to answer the purpose. Lime is often employed, in small quantities ; also borax, a salt which facilitates the fusion of the silica. Instead of the common alkalies, the sulphate of soda may be employed, in glass-making. But, in this case, it is necessary to liberate the alkali, by decomposing the sulphuric acid of the salt. This may be done, by char¬ coal, or, in flint-glass, by metallic lead. Lime is also used with this salt. Of the metallic oxides, which are added in different cases, the deutoxide of lead (red lead) is the most com¬ mon. This substance renders flint-glass more fusible, heavy, and tough, and more easy to be ground and cut. At the same time, it imparts to it a greater brilliancy, and refractive power. Black oxide of manganese, in small quantities, has the effect of cleansing the glass, or of ren¬ dering it more colorless and transparent. This effect it seems to produce, by imparting oxygen to the carbona¬ ceous impurities, thus forming with them carbonic acid, which subsequently escapes. Common nitre produces a similar effect. If too much manganese be added, it com¬ municates a purple tinge to the glass, which, however, may be destroyed, by a little charcoal or wood. Arsen- ious acid, (white arsenic,) in small quantities, promotes the clearness of glass ; but, if too much be used, it com¬ municates a milky whiteness. Its use, in drinking-ves¬ sels, is not free from danger, when the glass contains so much alkali, as to render any part of it soluble in acids. ^ ^ Crown Glass .—Glass is of various kinds, which are named, not only from the character of their ingredients, but from the mode in which they are wrought. The name of crown-glass is given to the best kind of window-glass, that w’hich is hardest, and most free from color. It is made almost entirely of sand and alkali, and a little lime, without lead, or any other metallic oxide, except a minute quantity of manganese, and sometimes of cobalt, which are added, to counteract the effect of any impurities, in giving color to the glass. Crown-glass requires a greater heat, 250 ARTS OF VITRIFICATION. to melt its ingredients, than those kinds, which contain a larger quantity of metallic oxide, especially of lead. Fritting .—After the materials have been intimately mixed, they are subjected to the operation, called fritting. This consists in exposing them to a dull, red heat, which is not sufficient to produce their fusion. The use of this process is, to drive off the carbonic acid, and other gase¬ ous and volatile matters, which would otherwise prove troublesome, by causing the materials to swell up in the glass-pots. The heat is gradually increased, and the ma¬ terials constantly stirred, for some hours, until they unite into a soft, adhesive mass ; the alkali having gradually combined with the silicious earth. The reason why the fritting is conducted at a low heat is, that, if a high tem¬ perature were applied, at once, the alkali would be driven off, before it had time to combine with the silica. Melting .—The homogeneous mass, or /rff, is next transferred to the glass-pots of the melting furnace. These are crucibles, made of the most refractory clays and sand. A quantity of old glass is commonly placed upon the top of the frit, and the heat of the furnace is raised to its greatest height, at which state it is continued for thirty or forty hours. During this time, the materials become perfectly united, and form a transparent, uniform, mass, free from specks and bubbles. The whole is then suf¬ fered to cool a little, by slackening the heat of the fur¬ nace, until it acquires sufficient tenacity to be wrought. Blowing .—The formation of window-glass is effected, by blowing the melted matter, or metal, as it is called, into hollow spheres, which are afterwards made to ex¬ pand into circular sheets. The workman is provided wdth a long, iron tube, one end of which he thrusts into the melted glass, turning it round, until a certain quantity, sufficient for the purpose, is gathered, or adheres to the extremity. The tube is then withdrawn from the furnace, the lump of glass, which adheres, is rolled upon a smooth iron table, and the workman blow's strongly, with his mouth, through the tube. The glass, in consequence of its ductility, is gradually inflated, like a bladder, and is prevented from falling off, by a rotary motion, constantly ANNEALING.-BROAD-GLASS. 251 communicated to the tube. The inflation is assisted by the heat, which causes the air and moisture of the breath to expand, with great power. Whenever the glass be¬ comes so stifl', from cooling, as to render the inflation difficult, it is again held over the fire to soften it, and the blowing is repeated, until the globe is expanded to the requisite thinness. It is then received, by another work¬ man, upon an iron rod,* while the blowing-iron is detach¬ ed. It is now opened at its extremity, and, by means of the centrifugal force, acquired from its rapid whirling, it spreads into a smooth, uniform sheet, of equal thickness throughout, excepting a prominence at the centre, where the iron rod was attached. Annealing .—After the glass has received the shape which it is to retain, it is transferred to a hot chamber, or annealing furnace, in which its temperature is gradually reduced, until it becomes cold. This process is indis¬ pensable to the durability of glass ; for, if it is cooled too suddenly, it becomes extremely brittle, and flies to pieces, upon the slightest touch of any hard substance. This effect is shown, in the substances called Rupert^s-drops, which are made, by suddenly cooling drops of green glass, by letting them fall into cold water. These drops fly to pieces, with an explosion, whenever their smaller extrem¬ ity is broken off. 'I'he Bologna-phials, and some other vessels of unannealed glass, break into a thousand pieces, if a flint, or other hard and angular substance, is dropped into them. This phenomenon seems to depend upon some permanent and strong inequality of pressure ; for when tliese drops are heated so red as to be soft, and left to cool, gradually, the property of bursting is lost, and the specific gravity of the drop is increased. Broad Glass .—This is a coarser kind of window-glass, and is made from sand, with kelp and soap-boilers’ waste- It is blown into hollow cones, about a foot in diameter, and these, while hot, are touched on one side with a cold iron, dipped in water. This produces a crack, which runs through the length of the cone, nearly in a right line. ♦ Called a punt, or printing-iron. 252 ARTS OF VITRIFICATION. The glass then expands into a sheet, in its form resemb¬ ling, somewhat, the shape of a fan. This appears to have been one of the oldest methods of manufacturing glass. Flint Glass. —Flint-glass, so called, from its having been originally made of pulverized flints, differs from win¬ dow-glass, in containing a large quantity of the red oxide of lead. The proportions of its materials differ ; but, in round numbers, it consists of about tlu’ee parts of fine sand, two of red lead, and one of pearlash, with small quantities of nitre, arsenic, and manganese. It fuses at a lower temperature than crown-glass, has a beautiful trans¬ parency, a great refractive power, and a comparative soft¬ ness, which enables it to be cut and polished, with ease. On this account, it is much used for glass vessels, of every description, and especially those wdiich are intended to be ornamented, by cutting. It is also employed for lenses, and other optical glasses. Flint-glass is worked, by blow¬ ing, moulding, pressing, and grinding. Articles of com¬ plex form, such as lamps and wine-glasses, are formed in pieces, which are afterwards joined, by simple contact, while the glass is hot. It appears, that the red lead, used in the manufacture of flint-glass, gives up a part of its oxy¬ gen, and passes to the state of a protoxide. Bottle Glass .—Common green glass, of which bottles are made, is the cheapest kind, and formed of the most ordinary materials. It is^composed of sand, with lime, and sometimes clay, and alkaline ashes, of any kind, such as kelp, barilla, or even wood-ashes. The green color is owing to the impurities in the ashes, but chiefly, to oxide of iron. This glass is hard, strong, and well vitri¬ fied. It is less subject to corrosion, by strong acids, than flint-glass; and is superior to any cheap material, for the purposes to which it is ordinarily applied. Cylinder Glass .—The plates of crown-glass, which are obtained in the common manner, by blowing them in circular plates, afford the common material for window- glass ; being cut into squares, by first marking the surface deeply, with a diamond, and then breaking the glass, in the same directions ; the crack always following the exact course of the incision, made by the diamond. But there PLATE-GLASS. 253 is always a loss, or waste, in cutting squares, from a cir¬ cular plate ; besides which, they can never be very large, owing to the protuberance, or buWs-eye, which fills the centre of the plate ; so that a square can never be larger, than can be described within less than half the circle. To remedy this disadvantage, plates for looking-glasses, and others, of large size, are executed in a different way, either by blowing them in cylinders, or by casting them in plates, at first. Cylinder glass is blown, at first, in spheres, like window- glass. These are elongated into spheroids, by a swinging motion, which the workman gives to his rod. The ends of this spheroid are successively perforated, thus conver¬ ting it into an irregular cylinder. One side of this cylinder is cut through, with shears, and the glass is laid upon a flat surface, where it expands into a uniform plate, with¬ out any protuberance. It is then annealed, by diminishing the heat, in the common way. When the plates are in¬ tended for looking-glasses, the finest materials are used, and the heat kept at its greatest height, for a long time, to dissipate all impurities, and remove any specks or bub¬ bles. Plate Glass. —Looking-glass plates may be blown in cylinders, when they do not exceed about four feet in length. But they cannot well be blown, of a larger size than this, from such a quantity of glass as the rod will take up, without becoming too tbin to bear polishing. Plates, however, may be made of more than double this size, by another process, which is called castings and which is the only mode by which very large plates are produced. When glass is to be cast, it is melted, in great quanti¬ ties, in large pots, or reservoirs, until it is in a state of perfect fusion, in vvbich state it is kept for a long time. It is then drawn out, by means of iron cisterns, of consid¬ erable size, which are low'ered into the furnace, filled, and raised out, by machinery. The glass is poured out from these cisterns,.upon tables of polished copper, of a large size, having a rim elevated as high as the intended thick¬ ness of the plate. In order to spread it perfectly, and to II. 22 xn. 254 ARTS OF VITRIFICATION. make the two surfaces parallel, a heavy roller of polished copper, weighing five hundred pounds, or more, is rolled over the plate, resting upon the rim, at the edges. The glass, which is beginning to grow stiff, is pressed down, and spread equally, the excess being driven before the rol¬ ler, till it falls off at the extremity of the table. The plate is then ready to be annealed. As the plates, which are cast for looking-glasses, are always uneven and dull, at their surface, it is necessary to grind and polish them, before they are fit for use. The process, employed for producing a perfectly even and smooth surface, is very similar to that employed in polishing marble ; except that the glass, being the harder substance, requires more labor and nicety, in the oper¬ ation. The plate to be polished is first cemented to a table of wood or stone, with plaster of Paris. A quan¬ tity of wet sand or emery is spread upon it, and anoth¬ er glass plate, similarly cemented to another wooden sur¬ face, is brought in contact with it. The two plates are then rubbed together, until the surfaces have become mu¬ tually smooth and plane. The emery, which is first used, is succeeded by emery of a finer grain, and the last polish is given by colcothar or putty. When one surface has become perfectly polished, the cement is removed, the plate turned, and the opposite side polished in the same manner. As the grinding of glass causes an expenditure of a considerable portion of its substance, a great waste of glass takes place, when foreign materials are employed, in the manner which has been described. To prevent this loss, a more economical mode has been introduced, in which the glass is ground with pure Jlint, reduced to powder. The mixture of glass and flint, which is left, after the operation, is valuable, for forming fresh glass. JMoulding .—A variety of ornamental forms are pro¬ duced, upon the surface of glass vessels, by impressions given to them with a metallic mould, while the glass is in a hot state. Flint-glass is the kind which is used for articles, intended to possess much brilliancy ; but coarser kinds, even of colored glass, are also subjected to the PRESSING.-CUTTING. 255 same process. The simplest manner, in which the ope¬ ration is conducted, consists, in blowing the glass into the mould, till it receives the impression, on its outside. For this purpose, a quantity of glass, sufficient to form the intended vessel, is taken up on the end of a pipe, and in¬ serted at the top of the mould. The workman then blows, with his mouth, till a hollow portion of glass is driven into the mould, and expands, so as to fill every part, and re¬ ceive an impression on its outside. Tlie mould is usual¬ ly made of copper, with the figure cut on i_ts inside, and opens with hinges, to permit the glass to be inserted, and taken out. As the mould is, of necessity, much cold¬ er than the glass, the latter substance is chilled, at its surface, as soon as it comes in contact with the cop¬ per ; hence its ductility is impaired, and the impression given is never so sharp as that which is obtained with substances, which are nearly at the same temperatures. Moulded bottles, phials, decanters, &c., are made in this way. Pressing .—An improvement has been made, in the process of moulding glass, by subjecting the material to pressure, on the inside and outside, at the same time, by different parts of a mould, which are brought suddenly together, by mechanical power. This process has been carried to great perfection, in several of the manufacto¬ ries in this country,* and produces specimens, which compare with cut glass, in the accuracy and beauty of the workmanship. It is applied only to solid articles, and to vessels which are not contracted at top. The hot glass being dropped into the mould, a part, called the follower., answering to the inside or top of the vessel, or other article, is immediately pressed down upon it, by a lever, and the glass is thus stamped with a very distinct impression of the figure, on both sides at once. The glass vessel is sometimes transferred from the mould to another receptacle, called the receiver, in order to pre¬ serve its shape, till it is cool enough to stand. Cutting .—The name of cut-glass is given, in com ♦ Particularly, at Lechraere’s Point, and Sandwich. 256 ARTS OF VITRIFICATION. merce, to glass which is ground and polished, in figures^ with smooth surfaces, appearing as if cut by incisions of a sharp instrument. This operation is chiefly confined to flint-glass, which, being more tough, soft, and brilliant, than the other kinds, is more easily wrought, and pro¬ duces specimens of greater lustre. An establishment for cutting glass, contains a great number of small wheels, of stone, metal, and wood, which are made to revolve rap¬ idly, by a steam-engine or other power. The cutting of the glass consists entirely, in grinding away successive portions, by holding them upon the surface of these wheels. The first, or rough cutting, is sometimes given by wheels of stone, resembling grindstones. Afterwards, wheels of iron are used, having their edges covered with sharp sand, or with emery, in different states of fineness. The last polish is given by brush-wheels, covered with putty, which is an oxide of tin and lead. To prevent the fric¬ tion from exciting so much heat, as to endanger the glass a small stream of water continually drops upon the sui face of the wheel. Stained Glass .—The name of staining has been ap plied to the process, by which painting, with vitrifiable colors, is executed upon the surface of glass. The pig¬ ments used are, chiefly, metallic oxides, which do not ex¬ hibit their full color, until they have been exposed to the heat of the furnace. This art has been repeatedly des¬ cribed, as being no longer known ; but this is not the fact, except in respect to some particular colors, which are found in the windows of the ancient cathedrals. The metallic oxides, used in staining glass, are difficult of fusion ; on which account, it is necessary to mix them with a flux, composed of glass, with lead or borax. This renders the oxide fusible, at a temperature which does not injure its color ; also, by enveloping the particles, it causes them to adhere to tlie glass, and afterwards pro¬ tects them from the atmosphere. A very beautiful violet, but liable to turn blue, is made from a flux, composed of borax and flint-glass, colored with one sixth part of the purple of Cassius, precipitated from muriate of gold, by protomuriate of tin. ENAMELLING. 257 A fine red is made from red oxide of iron, prepared by nitric acid and heat, mixed with a flux of borax, and a small proportion of red lead. A yellow, equal in beauty to that produced by the an¬ cients, may be made from muriate of silver, oxide of zinc, white clay, and the yellow oxide of iron, mixed to¬ gether, without any flux. A powder remains on the sur¬ face, after the glass has been baked ; but this is easily cleaned off. Blue is produced by oxide of cobalt, with a flux, com¬ posed of fine sand, purified pearlash, and red lead. Black is produced, by mixing the composition for blue, with the oxides of manganese and iron. To stain glass green, it may be painted blue, on one side, and yellow, on the other. The colors, ground with water, being laid upon the glass, must be exposed to heat, under a muftle, so as to be heated equally, until the color is melted upon the sur¬ face. To prevent the panes of glass from bending, they are placed upon a bed of bone-ashes, of quicklime, or of unglazed porcelain. A bed of gypsum has been recom¬ mended ; but the sulphuric acid, exhaling from it, is apt to injure the glass. Among ancient specimens of painted glass, some pieces have been found, in which the colors penetrate through the glass, so that the figure appears in any section, made parallel to the surface. It is supposed, that such pieces can only have been made in the manner of mosaic, by ac¬ cumulating transverse filaments of glass, of different col¬ ors, and uniting them by heat, the process being one of great labor. They are described by Winckelmann, and Caylus, from some specimens brought from Rome. Enamelling .—Enamels are compositions of various substances, which, when vitrified upon the surface of opaque bodies, communicate their colors, and produce the effect of painting. F.namels differ from stained glass, as a common picture differs from a transparency ; the former producing its effect, when viewed by reflected, and the latter by transmitted, light. Enamels are exe¬ cuted upon the surface of copper, and other metals, bv 22 * 258 ARTS OF VITRIFICATION. a method, similar to painting. One coat, or color, often requires to be vitrified, before another is laid upon it; and thus the plate, to be enamelled, is obliged to be ex¬ posed to heat, several successive times. Transparent enamels are usually rendered opaque, by adding putty, or the white oxide of tin, to them. The basis of all enamels is, therefore, a transparent and fusi¬ ble glass. The oxide of tin renders this of a beautiful white, the perfection of which is greater, when a small quantity of manganese is likewise added. If the oxide of tin be not sufficient to destroy the transparency of the mixture, it produces a semi-opaque glass, resembling the opal. The metals, employed as coloring materials, are, 1. Gold. The purple of Cassius imparts a fine ruby tint. 2. Silver. Oxide, or phosphate, of silver, gives a yellow color. 3. Iron. The oxides of iron produce green, yel¬ low, and brown, depending upon the state of oxidizement, and quantity. 4. Copper. The oxides of copper give a rich green ; they also produce a red, when mixed with a small proportion of tartar, which tends, partially, to re¬ duce the oxide. 5. Antimony imparts a rich yellow. 6. Manganese. The black oxide of this metal, in large quantities, forms a black glass ; in smaller quantities, vari¬ ous shades of purple. 7. Cobalt, in the state of oxide, gives beautiful blues, of various shades ; and, with the yel¬ low of antimony, or lead, it produces green. 8. Chrome produces fine greens and reds, depending upon its state of oxidizement. Jlrtijicial Gems .—The great value of the precious stones has led to artificial imitations of their color and lustre, by compositions in glass. In order to approximate, as near as possible, to the brilliancy, and refractive power, of native gems, a basis, called a paste, is made from the finest flint-glass, composed of selected materials, combin¬ ed, in different proportions, according to the preference of the manufacturer. This is mixed with metallic oxides, capable of producing the desired color. A great num¬ ber of complex recipes are in use, among manufacturers of these articles- DEVITRIFICATION.-REAUMUR’s PORCELAIN. 259 Devitrification .—It is found, that, if certain kinds of glass be exposed to heat, sufficient to keep them in a soft state, for some hours, and are suffered to cool, gradually, they lose their transparency, and pass into the state of an opaque substance, of a grayish white color. M. Darlri- gues,* who has examined the cause of this change, as¬ serts, that it is owing to a real crystallization of the vitreous silicate. Common bottle-glass is most easily changed, in this manner ; while those varieties, which contain neither lime, nor alumina, are the most difficult to devitrify. In all cases, glass, which has undergone this change, requires a stronger heat to melt it, than before. Reaumur's Porcelain ,—It has been frequently observ¬ ed, that, during the annealing of green glass, some parts of it become white, and opaque. M. Reaumur made experi¬ ments on this apparent devitrification of glass, and found it was owing to the alkali flying off, by the too long con¬ tinuance, or too great degree, of the heat, and that the opaque, changed glass, had acquired the quality of bear¬ ing sudden transitions of heat and cold, as well as the best porcelain. For the purpose of making vessels, of this kind, com¬ mon bottle-glass is chosen, and blown into the proper form. The vessel is then to be filled to the top, with a mixture of white sand and gypsum, and is set in a large crucible, upon a quantity of the same mixture, with which the glass vessels must also be surrounded, and covered over, and the whole pressed down, rather hard. The crucible is then to be covered with a lid, the junctures well luted, and put into a potter’s kiln, where it remains, during the whole time that the pottery is baking ; after which, the glass will be found changed into a milk-white porcelain. An imitation of porcelain, which is lately introduced into our shops, and which combines whiteness with a beautiful semi-transparency, is made of flint-glass, con¬ taining a portion of white arsenic, on which its opacity depends. * Journal de Physique, 1804.—Thenard, Chimie, ii. 473 260 ARTS OF VITRIFICATION. Crystallo Ceramie .—This name is given to an elegant, but difficult, species of manufacture, in which medallions, portraits, and other subjects, executed in an opaque mate¬ rial, are enclosed, or encrusted, with glass. This art was first attempted, by enclosing, in glass, small figures, made of a peculiar kind of clay ; but these experiments were only in few instances successful, owing to the unequal ex¬ pansion and contraction of the two substances, and theii consequent fracture. More recently, a composition has been employed, for the opaque figure, which is less liable to these accidents. It is necessary, that the substance, employed in these devices, should be less fusible than glass, incapable of generating air, and, at the same time, susceptible of expansion and contraction, as the glass becomes hot or cold. The ornamental figures are intro¬ duced into the glass while hot, and thus become incorpor¬ ated with it. Glass Thread .—The great ductility of glass is one of its most remarkable properties. When heated to a sufficient degree, it may not only be moulded, into any possible form, with the utmost facility, but it can be drawn out into the finest fibres. The method of spinning glass is very simple. The operator holds a piece of glass over the flame of a lamp, with one hand ; he then fixes a hook to the melted mass, and, by withdrawing it, obtains a thread of glass, attached to the hook. The hook is then fixed in the circumference of a cylindrical drum, which can be turned round by the hand ; and a rapid, rotary motion being given to the drum, the glass is drawn in the finest threads, from the fluid mass, and coiled round the cylin¬ drical circumference. M. Reaumur supposed, with great reason, that the flexibility of glass increased with the fine¬ ness of the threads, and he therefore conjectured, that, if they were drawn to a sufficient degree of fineness, they might be used in the fabrication of stuffs. He succeeded in making them as fine as a spider’s web ; but he was nev¬ er able to obtain them of a sufficient length, when their di¬ ameter was so much reduced. The circumference of these threads is generally a flat oval, about three or four times as broad as it is thick. By using opaque and REMARKS. 261 transparent glass, of different colors, artists have been able to produce many beautiful ornaments. M. Bonnet, and others, have succeeded in obtaining glass fibres, of such fineness and flexibility, as to admit of being woven into cloth, of a very brilliant, silvery appearance. Remarks. —Pure glass possesses the remarkable prop¬ erty, of suffering no change by the application of an intense heat. The effect of great heats is only to melt the glass, or to dissipate it in vapor ; but, as long as any of the glass remains, it still preserves its transparency, and other dis¬ tinguishing properties. Of all the solid substances, whose expansibility has been accurately examined, glass possesses the property of being least affected by heat or cold. Its expansion, according to General Roy, with an increase of heat, equal to one hundred and eighty degrees of Fahrenheit’s thermometer, is only 0.000776, while that of platina is 0.000856, and that of hammered zinc, 0.003011. On account of this property, glass is peculiarly fitted for con¬ taining fluids, whose expansions are under examination, as its own change of form may, in ordinary cases, be neglec¬ ted. For the same reason, it is better than any other substance, for the simple pendulum of a clock. The invention of glass seems to have been extremely ancient, and some curious specimens are found, in the sar¬ cophagi of Egyptian mummies. Glass windows appear not to have been in use, among the Romans of the Augus¬ tan age ; though vessels and plates of glass are found at Herculaneum, and Pompeii. Most of the itnportant im¬ provements, in the manufacture of this substance, have been made by the moderns. Works of Reff.rence.—Parkes’s Chemical Essays, 8vo. vol. ii.;— Loysel, Essai sur I'Art de la Verrerie, 8vo. 1800;— Hrog- NiART, Art de 1'Emailleur, Annales de Chimie, tom. ix. and otlier works ;—Franklin Journal, v. 80 ;—.Article Glass in Rees’ Cyclope¬ dia, and in the Edinburgh Encyclopedia ;— Lardner’s Cabinet Cy¬ clopedia, 12mo. vol. xxvi;— Chaptal, Chimie Appliqnee aux Arts, 4 vols. 8vo. 1806 ;— Gray’s Operative Chemist, 8vo. 1828;— Then- ARD, Traill de Chimie, vol. ii.; —Brande’s Chemistry ; —Heck¬ man’s History of Inventions, 4 vols. 8vo. translated 1797;—VV'^orks of Neri, Blancourt, Kunckel, Reaumur, &c. 262 ARTS OF INDURATION BY HEAT. CHAPTER XXII. ARTS OF INDURATION BY HEAT. Bricks, Pressed Bricks, Tiles, Terra Cotta, Crucibles, Pottery, Opera¬ tions, Stone Ware, White Ware, Throwing, Pressing, Casting, Burning, Printing, Glazing, China Ware, European Porcelain, Etruscan Vases. Common clay, with its varieties, consisting essentially of alumina and silica, also, the artificial imitations of clay, into which these earths enter, possess properties, adapted to render them highly useful in the arts. When mixed with water, they form a ductile and tenacious paste, ca¬ pable of being moulded into various forms, and of acquir¬ ing, when exposed to the heat of a furnace, a durable and stony hardness. These compounds are used in dif¬ ferent states, to form the materials, both for the largest structures, and the most delicate ornaments ; and they are surpassed by few substances, in the power of resisting the effects of exposure and time. Bricks, tiles, terra¬ cotta, pottery, and porcelain, are the most noticeable pro¬ ducts of the branch of industry, in the operations of which indurated clay is the material. Bricks .—The use of bricks, in building, may be traced to the earliest ages, and they are found among the ruins of almost every ancient nation. The walls of Babylon, some of the ancient structures of Egypt, and Persia, tlie walls of Athens, the Rotunda of the Pantheon, the Tem¬ ple of Peace, and the ThernicE, at Rome, were all of brick. The earliest bricks were dried in the sun, and were never exposed to great heat, as appears from the fact, that they contain reeds and straws, upon which no mark of burning is visible. These bricks owe their preservation to the extreme dryness of the climate, in which they have re¬ mained ; since the earth, of which they are made, often crumbles to pieces, when immersed in water, after having kept its shape for more than two thousand years. This PRESSED BRICKS. 263 is the case, with some of the Babylonian bricks, with in¬ scriptions in the arrow-headed character, which have been brought to this country. The ancients, however, at a later period, burnt their bricks ; and it is these, chiefly, which remain at the present day. The antique bricks were larger than those employed by the moderns, and were al¬ most universally of a square form. Besides bricks made of clay, the ancients also employed a kind of factitious stone, composed of a calcareous mortar.* Modern bricks receive their hardness from exposure to heat, in the process of burning. The common clay, of which they are made, consists of a mixture of argillaceous earth, and sand. Most of our common clays contain, also, oxide of iron, which causes the bricks to turn red, in burn¬ ing. Pure clays become white in the furnace, such as that of which pipes are made, and common crockery-ware. Clay, after it is taken from the earth, requires to be thoroughly mixed, incorporated, and mellowed, before it is fit for the manufacture of bricks. For this purpose, it is to be dug in the summer, or autumn, and exposed to the influence of the frost, through the winter. It should be worked over repeatedly, with the spade, and not made into bricks, till the ensuing spring, previously to which, it is well tempered, either by treading it, with oxen, or by a horse-mill, till it is reduced to a tough, homogeneous paste. In proportion to the labor bestowed on this pro¬ cess, the bricks become solid, hard, and strong. The clay, after being thus prepared, is forced into moulds, to re¬ ceive the shape of bricks, and afterwards dried in the sun. Pressed bricks^ which are used to form the facing of walls, in the better kinds of structures, are finished in a machine. The roughness, and change of form, to which common bricks are liable, is owing, in jiart, to the evap¬ oration of a portion of the water, which the clay contains. To remedy the difliculty, arising from this cause, the bricks, after being moulded, in the common manner, are exposed to the sun, till they are nearly dried ; retain¬ ing, however, sufScient plasticity, to be still capable of a *Some travellers have even advanced nn opinion, that the Pyramids of Egypt are censtructed with an artificial stone. 264 ARTS OF INDURATION BY HEAT. slight change of form. In this state, they are placed in an iron mould, and subjected to a strong pressure, by which they become regular in shape, and very smooth. A machine usually contains a number of moulds, arranged in a circle, or otherwise; so that the power is applied to them in succession, and the bricks pressed with rapidity. The burning of bricks is commonly performed, in this country, by forming them into large, square piles, de¬ nominated clamps^ or, with us, kilns^ having flues, or cavities, at the bottom, for the insertion of the fuel, and interstices between the bricks, for the fire and hot air to penetrate. A fire is kindled in these cavities, and grad¬ ually increased, for the first twelve hours, after which, it is kept up, at a uniform height, for several days and nights, till the bricks are sufficiently burned. Much care and experience are necessary, in regulating the fire, since too much heat vitrifies them, and too little, leaves them soft and friable. In some places, the burning of bricks is conducted in permanent kilns, erected for the purpose. Tiles .—Tiles are plates of burnt clay, resembling bricks, in their composition and manufacture, and used for the covering of roofs. They are necessarily made thicker than slates or shingles, and thus impose a greater weight upon the roofs. Their tendency to absorb water pro¬ motes the decay of the wood-work beneath them. Tiles are usually shaped in such a manner, that the edge of one tile receives the edge of that next to it, so that water cannot percolate between them.* Tiles, both of burnt clay, and marble, were used by the ancients ; and the for¬ mer continue to be employed in various parts of Europe. Floors, made of flat tiles, are used in many countries, particularly in Italy. Terra Cotta .—The Italian name, terra-cotta., in French, terre-cuite, in its most general sense, implies clay, in¬ durated by heat. In the arts, however, its use seems to be restricted to the finer clays, in which ornamental de¬ signs have been executed, both by the ancients and mod¬ erns. Not only vases, but imitations of sculpture, and * For different forms of tiles, used at Florence, Trieste, &c., see Cadell’s Journey in Italy, and Carniola, Plate X. CRUCIBLES.-POTTERY. 265 architectural decorations, are successfully made, from this material. Among other things, a complete restora¬ tion of the Choragic monument of Lysicrates, at Athens, has been made from terra-cotta, in the court of the Lou¬ vre, at Paris. From the facility with which it is mould¬ ed into any form, this substance would be of great use in architecture, were it not for the unequal shrinking of the clay, from heat, and the difficulty of preserving, accurate¬ ly, the original proportions. Crucibles. —Crucibles, melting-pots, and other vessels, intended for use in the furnace, require to be made of substances, which sustain a high temperature, without fusion. When they are made of about one part of pure clay, mixed with three of sand, and slowly dried, and annealed, they are found to bear a great heat, and will re¬ tain most of the medals which are melted for use in the arts. Such crucibles, however, are liable to be acted upon and destroyed, at high temperatures, if the metals are suffered to become oxidized, or if saline fluxes are used. To prevent this accident, some crucibles are made entirely of clay, which is burnt, coarsely powdered, and mixed with fresh clay. These are found very re¬ fractory in the furnace. Crucibles are also made of plain Stourbridge clay, of W'eilgewood’s ware, of graphite, and of platina. Poltery .—In manufactures of vessels, from argilla¬ ceous compounds, the diflerent degrees of beauty, and costliness, depend upon the quality of the raw material used, and upon the labor and skill, expended in the op¬ eration. The cheapest products of the art, are those made of common clay, similar to that of which bricks are formed, and which, from the iron it contains, usually turns red, in burning. Next to this, is the common crockery- ware, formed of the purer and whiter clays, in which iron exists, only in minute quantities. Porcelain, which is the most beautiful and expensive of all, is formed only from argillaceous minerals, of extreme delicacy, united with silicious earths, capable of communicating to them a semi-transparency, by means of its vitrification. Clay, although it is a compound body, and possesses ii. 23 XII. 266 ARTS OF INDURATION BY HEAT. more silica than alumina, nevertheless, derives characters from the latter, which abundantly distinguish it from min¬ erals, which are more purely silicious. The processes of its manufacture are, in most respects, the reverse of those applied to glass, that substance being softened by heat, and wrought at a high temperature, whereas, the clay's wrought while cold, and afterwards hardened by heat. Operations .—Though the various kinds of pottery and porcelain differ from each other, in the details of their manufacture, yet there are certain general principles, and processes, which are common to them all. The first belongs to the preparation of the clay, and consists in di¬ viding and washing it, till it acquires the requisite fine¬ ness. The quality of the clay requires the intermixture of a certain proportion of silicious earth, the effect of which is to increase its firmness, and render it less liable to shrink and crack, on exposure to heat. In common clay, a sufficient quantity of sand exists, in a state oi natural mixture, to answer this purpose. But in the finer kinds, an artificial admixture of silica is necessary. The paste, which is thus formed, is thoroughly beaten and kneaded, to render it ductile, and to drive out the air. It is then ready to receive its form. The form of the vessel, intended to be made, is given to the clay, either by turning it on a wheel, or by casting it in a mould. When dry, it is transferred to the oven, or furnace, and there burnt, till it acquires a sufficient degree of hardness, for use. Since, however, the clay is still porous, and, of course, penetrable to water, it is necessary to glaze it. This is done, by covering the surface with some vitrifiable substance, and exposing it, a second time, to heat, until this substance is converted into a coating of glass. In the coarse earthen ware, which is made of common clay, the clay, after being mixed and kneaded, until it has acquired the proper ductility, is transferred to a sort of revolving table, called the wheel. A piece of clay, of sufficient size, being placed in the centre of this table, a rotary motion is communicated to it, by the feet. The potter then begins to shape it, with his hands, which are previously wet, to prevent its adhering to the fingers STONE-WARE.-WHITE-WARE. 267 The rotary motion gives it a circular form, and it is gradually wrought up to the intended shape, a tool being occasionally used, to assist the finishing. The vessels are now set aside, to dry ; after which, they are baked in the oven, or kiln. The glazing, of this kind of pottery, is given by metallic oxides, which vitrify at a low heat. A yellow glazing is communicated, by the oxide of lead ; black, by the oxide of manganese ; and white, by the oxide of tin. Unglazed ware is porous, and permeable to water, as is seen in common flower-pots, and coolers. Stone Ware .—The kinds of pottery, denominated stone-ware, may be formed of the clays, which are used for other vessels, by applying to them a much greater degree of heat, the eflect of which is, to increase, very much, their strength and solidity. These vessels do not require to be glazed, with any metallic oxides, but afford the material of their own glazing, by a vitrification of their surface. When the furnace, in which they are burnt, has arrived at its greatest heat, a quantity of muriate of soda, or common salt, is thrown into the body of the kiln. The salt rises in vapor, and envelopes the hot ware, and, by the combination of its alkali with the silicious particles on the surface of the ware, a perfect vitrification is pro¬ duced. This glazing, consisting of an earthy glass, is in¬ soluble in most chemical agents, and is free from the ob¬ jections, to which vessels, glazed with lead, are liable, that of communicating an unwholesome quality to liquids contained in them, by the solution of the lead in common acids, which they frequently contain. White Ware .—The better sorts of earthen ware are made of white clay, or of clay containing so little oxide of iron, that it does not turn red in burning, but, on the contrary, improves its whiteness in the furnace. This kind, commonly called pipe clay, is found very pure in Devonshire, and Dorsetshire, in England. In the manu¬ factory of Mr. Wedgewood, to whose industry and in¬ genuity the public are indebted, for some of ihe finest specimens of the art, the clay is prepared, by first bring¬ ing it to a state of minute division, by the aid of machine¬ ry. This machinery consists of a series of iron blades, 268 ARTS OF INDURATION BY HEAT. or knives, fixed to an upright axis, and made to revolve in a cylinder, and intersecting, or passing between, anoth¬ er set of blades, which are fixed to the cylinder. The clay, by the continual intersection of these blades, is minutely divided, and, when sufficiently fine, is transferred to a vat. It is here agitated, with water, until it assumes the consistence of a pulp, so thin, that the coarser or stony particles can subside to the bottom, after a little rest, while the finer clay remains in suspension. This last is poured oft’, and suff'ered to subside, after which it is passed through sieves, of different fineness, and be¬ comes sufficiently attenuated for use. To this clay is added a certain quantity of flint, re¬ duced to powder, by beating it red hot, and throwing it into cold water, to diminish the cohesion of its parts. Afterwards, it is pounded by machinery, ground in a mill, sifted, and washed, precisely as the clay is treated, and made into a similar pulp. In this state, the two ingredi¬ ents are intimately mixed together, in such quantities, that the clay bears to the flint the proportion of about five to one. The object of adding flint to the clay is two-fold. It lessens the shrinking of the clay, in the fire, and thus ren¬ ders it less liable to warp and crack, in the burning. At the same time, by its partial fusion, it communicates to the ware that beautiful translucency, which is so much admired in porcelain, and of which the simple clay-wares are destitute. The fine pulp of flint and clay, being intimately mixed, is then exposed to evaporation, by a gentle heat, until the superfluous water is dissipated, and the mass reduced to a proper consistency to work. To produce a unifor¬ mity, in the thickness of the material, it is taken out, in successive pieces, which are repeatedly divided, struck, and pressed together, till every part becomes blended with the rest. Throicing .—The formation of circular vessels is done by the process called throwing, performed on the potter’s wheel, in the manner already described ; except that, ia large manufactories, the wheel is not turned by the oper- PRESSING.-CASTING.-BURNING. 269 ator himself, but by an assistant, or a steam-engine. The handles, and similar appendages, are made, by forcing the clay with a piston, through an aperture, of the size and shape which it is desired to produce. When formed, the handles are cemented to the ware, by a thin mixture of the clay with water, which the workmen call slip. The vessels, when complete, are dried, with a gradual heat, in a room, heated to eighty or ninety degrees, and, after being smoothed from any irregularities of surface, they are conveyed to the kiln. Pressing .—The only vessels which can be made in the wheel, or lathe, are those of a circular form. When the form is different, the vessel must be made, either by press-work, or casting. The press-work is executed in moulds, made of plaster of Paris, one half the figure be¬ ing on one side of the mould, and the other half, on the other side. These fit accurately together. The clay is first made into two flat pieces, of the thickness of the ar¬ ticles ; one of these is pressed into one side of the mould, and the other into the other side. The superfluous clay being cut away, the two sides of the mould are brought together, to unite the two halves of the vessel. The mould is now separated from the clay, and the article is finished, as to form. When dry, it is completed by the addition of handles or other parts, belonging to it. All vessels, of an oval form, or which have flat sides, may be made in this way. Casting .—In the third method, called casting, the clay is used in the state of pulp, sufficiently thin to flow. It is poured into moulds, made of plaster, by which the su¬ perfluous water being rapidly absorbed, the clay is depos¬ ited, and acquires suflicient solidity to preserve the shape communicated by the mould. It is then taken out, and dried, and transferred to the kiln. Burning .—All vessels, when formed, are in a very tender and frangible state, before they are submitted to the action of fire. The burning, or hardening, is per¬ formed in kilns ; and to preserve the ware from injury, it is enclosed in cases, or boxes, of burnt clay, called saggars, in which it is heated red hot, by the flame cir- 270 ARTS OF INDURATION BY HEAT. culating among the cases. The fire is kept up, from twen ty-four to forty-eight hours, and the saggars suffered to cool, before they are removed. The ware is then found to have acquired great hardness, and is converted into a dry, sonorous, and extremely bibulous, solid. In this state, it is called the biscuit. It adheres strongly to the tongue, and absorbs water in such quantities, that vessels, in this state, are used as coolers, being kept saturated with wa¬ ter, which, as it passes constantly to the outer surface, generates cold, by its evaporation. Printing .—When colors, or designs, are to be im¬ pressed upon the vessels, it is necessary, in most cases, that it should be done, before the ware is glazed. In China, the’drawings on the surface of porcelain, and oth¬ er wares, are executed by hand, with the pencil; and the same method is pursued in Europe, in elaborate pieces of workmanship. But, in the common figured white-ware, the designs are first engraved upon copper, and an im¬ pression taken on thin paper, in the common mode of copperplate-printing, except that the color is a metallic oxide. The paper is then moistened, applied closely to the biscuit, and rubbed on ; by which process, the color¬ ing matter is absorbed, in consequence of the porosity of the earthen material. The paper is then washed off, leaving the printed figure transferred to the sides of the vessel. Blue and white ware is printed with oxide of cobalt,* and a black color is imparted, by an admixture with the oxides of manganese and iron. Glazing .—To prevent the penetration of fluids, it is necessary, that vessels should be glazed, or covered, with a vitreous coating. The materials of .common glass would afford the most perfect glazing to crockery-ware, were it not that the ratio of its expansion and contrac¬ tion, is not the same with that of the clay ; so that a glazing of this sort is liable to cracks and fissures, when exposed to changes of temperature. A mixture, of equal parts of oxide of lead and ground flints, is found to be a * Mr. Parkes informs us, that such improvements are made in the manufacture of this article, that the Chinese potters are now supplied from England, with all the cobalt they consume. CHINA-WARE.-EUROPEAN PORCELAIN. 271 durable glaze, for the common cream-colored ware, and is generally used for that purpose. These materials are first ground to an extremely fine powder, and mixed with water, to form a thin liquid. The ware is dipped into this fluid, and drawn out. The moisture is soon absorb¬ ed by the clay, leaving the glazing particles upon the sur¬ face. These are afterwards melted, by the heat of the kiln, and constitute a uniform and durable vitreous coating. The English and French manufacturers find it neces¬ sary to harden their vessels, by heat, or to bring them to the state of biscuit, before they are glazed ; but the com¬ position used by the Chinese resists water, after it has been once dried in the air, so as to bear dipping in the glazing liquid, without injury. This gives them a great advantage, in the economy of fuel. China Ware .—The Chinese porcelain excels other kinds of ware, in the delicacy of its texture, and the par¬ tial transparency which it exhibits, when held against the light. It has been long known and manufactured, by the Chinese, but has never been successfully imitated, in Eu¬ rope, until within the last century. In China, porcelain is made by the union of two earths, to which they give the name of pelnntze., and kaolin., the former of which is fusible in the furnace, the latter, not. Both these earths are varieties of feldspar, the kaolin being feldspar, in a state of decomposition, and which is rendered infusible, by having lost the small quantity of potass, which originally entered into its composition. The petuntze is feldspar, undecom¬ posed. These earths are reduced to an impalpable pow¬ der, by processes, similar to those already described, and intimately blended together. When exposed to a strong heat, the petuntze partially melts, and, enveloping the in¬ fusible kaolin, communicates to it a fine semi-transparen¬ cy. The glazing is produced by tlte petuntze alone, ap¬ plied in minute powder to the ware, after it is dry. European Porcelain .—Since the nature of the Chi¬ nese earths has been understood, materials, nearly of the same kind, have been found, in difierent parts of Europe, and the manufacture of porcelain has been carried on in several countries, but particularly at Sevres, in France, 2'2 AF.fS OF INDURATION BT HEAT. with great success. The European porcelains, in the elegance and variety of their forms, and the beauty of the designs which are executed upon them, excel the manufactures of the Chinese. But the Oriental porcelain has not yet been equalled, in hardness, strength, durabili¬ ty, and the permanency of its glaze. Several of the processes, which are successfully practised by the Chi¬ nese, remain still to be learnt by Europeans. The man¬ ufacturers in Saxony are said to have approached most nearly, in their products, to the character of the Asiatic porcelain. The porcelain earths are found in various parts of the United States, and will, doubtless, hereafter constitute the material of important manufactures. The finer and more costly kinds of porcelain derive their value, not so much from the quality of their mate¬ rial, as from the labor bestowed on their external decora¬ tion. When the pieces are separately painted by hand, with devices of different subjects, their value, as speci¬ mens of art, depends upon the size of the piece, the num¬ ber and brilliancy of the colors employed, and, more especially, upon the skill and finish exhibited by the ar¬ tist, in the design. The manual part of the operation consists, in mixing the coloring oxide with a fluid medi¬ um, commonly an essential oil, and applying it with cam¬ els’ hair pencils. The colors used are the same, as those employed in other kinds of enamelling. When one color requires to be laid over another, this is performed by a second operation ; and it often happens, that a piece of porcelain has to go into the enamel-kiln, four or five times, when a great variety of colors is contained in the painting. Gilding upon porcelain is performed, by applying the gold, after its solution in nitro-muriatic acid, ground up with oil of turpentine, and mixed with a flux. When exposed to heat, the oxygen, if any is present, escapes, and a coating of metallic gold remains fixed to the porce¬ lain. This has, at first, the appearance of dead gold ; out is subsequently burnished, with an instrument of pol¬ ished steel, or with an agate, or blood-stone. The articles, called lustre-ware^ are of two kinds. The ETRUSCAN VASES. 273 first of these, called gold-lustre^ is made of red clay, and is brushed over with a thin coating of gold, obtained from its solution in nitro-muriatic acid, the acid being driven off by heat. The other kind is called silver-lustre^ and is made of the cream-colored ware, covered, in the same manner, with a film of platinum. Etruscan Vases .—This name is given to a kind of painted antique vases, of great beauty, lightness, and delicacy, which are dug up in the graves of lower Italy. Many of them are supposed to be of Grecian, and not of Etruscan, origin. Some of these vases are entirely black, and, in this case, there is no separate glazing ; but the in¬ terior of the mass has the same appearance with the out¬ side. Other vases are furnished with a simple black coating, but unlike the modern glazing. It appears, from analysis, that this black color is produced by a carbona¬ ceous substance, perhaps bitumen ; but the art of apply¬ ing it is unknown to the moderns. The celebrated Portland vase, discovered in the tomb of Alexander Severus, and for which the Dutchess of Portland paid a thousand guineas, is said to be made, not of porcelain, but of glass. The body of the urn consists of a deep-blue glass, ov^er which is applied a coating of white semi-transparent glass. The white covering ap¬ pears to have been cut away, by the lapidary, in the same way as the subjects of antique cameos on colored grounds. Mr. Wedgewood, at a great expense, produced imitations of this vase, in porcelain. Among the curiosities of this art, may be mentioned the magic porcelain of the Chinese. The figures upon the surface of this ware are executed in such a manner, that they are said to be invisible, when the vessels are empty,* but become apparent, when tlie vessels are filled with water. Works of Reference.—Parkes’s Chemical Essays, vol. ii.;— Rees’ Cyclopedia, and Edinburgh Encyclopedia, articles Pottery, Por¬ celain, &c. ;— Chaptal, Chimie Appliquee aux Arts, tom. iii. ;—■ Gray’s Operative Chemist, 8vo. 1828.— Lardner’s Cabinet Cy¬ clopedia, 12mo. vol. xxvi. • See the article Porcelain, in the Edinburgh Encyclopedia, ascribed to M. Drogniart. APPENDIX. I. — Artesian Wells. Under this name, is designated a cylindrical perfora¬ tion, bored vertically down through one or more of the geological strata of the earth, till it passes into a porous gravel bed, containing water placed under such incum¬ bent pressure, as to make it mount up tlirough the per¬ foration, either to the surface, or to a height convenient for the operation of a pump. In the first case, tliese wells are called spouting, or overflowing. This property is not directly proportional to the depth, as might at first sight be supposed, but to the subjacent pressure upon the water. We do not know exactly the period, at which the borer, or sound, was applied to the investigation of subterranean fountains, but we believe the first overflow¬ ing wells were made in the ancient French province of Ar¬ tois, whence the name of Artesian. These wells, of such importance to agriculture and manufactures, and which cost nothing to keep them in condition, have been in use, undoubtedly, for several centuries, in the northern depart¬ ments of France, and in the north of Italy ; but it is not more than fifty or sixty years, since they became known in England and Germany. There are now many such wells in London and its neighborhood, perforated through the immensely thick bed of the London clay, and even through some portions of the subjacent chalk. The bor¬ ing of such wells has given much insight into the geologi¬ cal structure of many districts. The formation of Artesian wells depends on two things, essentially distinct from each other ; 1. On an acquain¬ tance with the physical constitution, or nature, of the min- 276 APPENDIX. eral structure of each particular country ; and, 2. On the skilful direction of the processes, by which we can reach the water-level, and of those by which we can promote its ascent in the tube. We shall treat of the best method of making the well, and then offer some general remarks on the other subjects. The operations employed for penetrating the soil are entirely similar to those daily practised by the miner, in boring to find metallic veins ; but the well-excavator must resort to peculiar expedients to prevent the purer water, which comes from deep strata, mingling with the cruder waters of the alluvial beds near the surface of the ground, as also to prevent the small perforation getting eventually filled with rubbish. The cause of overflowing wells has been ascribed to various circumstances. But, as it is now generally ad¬ mitted, that the numerous springs which issue from the ground proceed from the infiltration of the waters, pro¬ gressively condensed in rain, dew, snow, &c., upon the surface of our globe, the theory of these interior stream¬ lets becomes by no means intricate ; being analogous to that of syphons and water-jets, as expounded in the trea¬ tises of physics. The waters are diffused, after conden¬ sation, upon the surface of the soil, and percolate down¬ wards through the various pores and fissures of the geo¬ logical strata, to be again united subterraneously in veins, rills, streamlets, or expanded films, of greater or less mag¬ nitude or regularity. The beds traversed by numerous disjunctions will give occasion to numerous interior cur¬ rents, in all directions, which cannot be recovered and brought to the day ; but when the ground is composed of strata of sand or gravel very permeable to water, sep¬ arated by other strata nearly impervious to it, reservoirs are formed to our hand, from which an abundant supply of water may be spontaneously raised. In this case, as soon as the upper stratum is perforated, the waters may rise, in consequence of the hydrostatic pressure upon the lower strata, and even overflow the surface in a constant stream, provided the level from which they proceed be proportionably higher. ARTESIAN WELLS. 277 The sheets of water occur, principally, at the separa¬ tion of two contiguous formations ; and, if the succession of the geological strata be considered, this distribution of the water will be seen to be its necessary consequence. In fact, the lower beds are frequently composed of com¬ pact sandstone or limestone, and the upper beds of clay. In level countries, the formations being almost always in horizontal beds, the waters which feed the Artesian wells must come from districts somewhat remote, where the strata are more elevated, as towards the secondary and transition rocks. The copious streams, condensed upon the sides of these colder lands, may be therefore regarded as the proper reservoirs of our wells. The situation of the intended well being determined upon, a circular hole is generally dug in the ground, about six or eight feet deep, and five or six feet wide. In the centre of this hole, the boring is carried on by two work¬ men below, assisted by a laborer above. The tools used are variously formed, in the shape of drills, chisels, picks, &c., screwed upon the end of a handle which is capable of being lengthened, as the work proceeds. The whole is suspended from an elastic hori¬ zontal pole, which is firmly fixed, at one end, while the other end can be moved, up and down, by a workman, producing a vibrating, or picking, motion. At the same lime, other workmen turn or vary the position of the drill, by means of a cross-bar, so that it acts as in the common mode of drilling rocks. Tl'lie dirt and broken stones are drawn up, by an instrument shaped somewhat like an auger, which is inserted, from time to lime, when the drill is withdrawn. It is obvious, that placing and displacing the lengths of rod, which is done every time that the auger is required to be introduced or withdrawn, must, of itself, be ex¬ tremely troublesome, independent of the labor of boring ; but yet the operation proceeds, when no unpropitious circumstance attends it, with a facility almost incredible. Sometimes, however, rocks intercept the way, which re¬ quire great labor to penetrate ; but this is always efiectec by pecking, which slowly pulverizes the stone. The most II. 24 XII. 278 APPENDIX. unpleasant circumstance attendant upon this business is the occasional breaking of a rod into tlie hole, which some¬ times creates a delay of many days, and an incalculable labor in drawing up the lower portion. When the water is obtained, in such quantities and of such quality as may be required, the hole is dressed or finished, by passing down it a diamond chisel, funnel¬ mouthed, with a triangular bit in its centre; this makes the sides smooth, previous to putting in the pipe. This chisel is attached to rods, and to the handle, as before described, and in its descent, the workmen continually walk round, by which the hole is made smooth and cy¬ lindrical. In the progress of the boring, frequent veins of water are passed through; but, as these are small streams, and perhaps impregnated with mineral substances, the operation is carried on, until an aperture is made into a main spring, which will flow up to the surface of the earth. This must, of course, depend upon the level of its source, which, if in a neighboring hill, will frequently cause the water to rise up, and produce a continued foun¬ tain. But, if the altitude of the distant spring happens to be below the level of the surface of the ground, where the boring is effected, it sometimes happens, that a well of considerable capacity is obliged to be dug down to that level, in order to form a reservoir, into which the water may flow, and whence it must be raised by a pump; while, in the former instance, a perpetual fountain may be obtained. Hence, it will always be a matter of doubt, in level countries, whether water can be procured, which would flow near to, or over, the surface ; if this cannot be effected, the process of boring will be of little or no ad¬ vantage, except as an experiment, to ascertain the fact. In order to keep the strata pure, and uncontaminated with mineral springs, the hole is cased, for a considerable depth, with a metallic pipe, about a quarter of an inch smaller than the bore. This is generally made of tin, though sometimes of copper or lead, in convenient lengths ; and, as each length is let down, it is held by a shoulder resting in a fork, while another length is sol¬ dered to it; by which means a continuous pipe is carried MINES. 279 through the bore, as far as may be found necessary, to exclude land-springs, and to prevent loose earth or sand from falling in, and choking the aperture.— lire’s ^Diction¬ ary of «/3rts,’&c. II.—Mines. Amidst the variety of bodies, apparently infinite, which compose the crust of the globe, geologists have demon¬ strated the prevalence of a few general systems of rocks, to which they have given the names of formations, or de¬ posits. A large proportion of these mineral systems con¬ sists of parallel planes, whose length and breadth greatly exceed their thickness ; on which account, they are called stratified rocks ; others occur in very thick blocks', with¬ out any parallel stratification, or horizontal seams, of con¬ siderable extent. The stratiform deposits are subdivided into two great classes ; the primary, and the secondary. The former seem to have been called into existence, before the crea¬ tion of organic matter, because they contain no exuviae of vegetable or animal beings ; while the latter are more or less interspersed, and sometimes replete, with organic re¬ mains. The primary strata are characterized, moreover, by the nearly vertical, or highly inclined, position of their planes ; the secondary lie, for the most part, in a nearly horizontal position. Where the primitive mountains graduate down into the plains, rocks of an intermediate character appear, which, though possessing a nearly vertical position, contain a'fevv vestiges of animal beings, especially shells. These have been called transition, to indicate their being the passing links between the first and second systems of ancient de¬ posits. They are distinguished by the fractured and ce¬ mented texture of their planes, for which reason they are sometimes called, conglomerate. Between these, and the truly secondary rocks, another very valuable series is interposed, in certain districts of the globe ; namely, the coal-measures, the paramount for¬ mation of Great Britain. The coal strata are disposed in a basin form, and alternate with parallel beds of sand- 280 APPENDIX. Stone, slate-clay, iron-stone, and occasionally limestone. Some geologists have called the coal-measures the medi¬ al formation. In every mineral plane, the inclination and direction are to be noted ; the former, being the angle which it forms with the horizon, the latter, the point of the azimuth, or horizon, towards which it dips, as west, northeast, south, &c. The direction of the bed is that of a horizontal line drawn in its plane ; and which is also denoted by the point of the compass. Since the lines of direction and inclina¬ tion are at right angles to each other, the first may always be inferred from the second ; for when a stratum is said to dip to the east or west, this implies, that its direction is north and south. The smaller sinuosities of the bed are not taken into account, just as the windings of a river are neglected, in stating the line of its course. JMasses are mineral deposits, not extensively spread in parallel planes, but irregular heaps, rounded or oval, en¬ veloped, in whole or in a great measure, by rocks of a different kind. Lenticular masses being frequently placed between two horizontal, or inclined, strata, have been sometimes supposed to be stratiform themselves, and have been accordingly denominated by the Germans, liegende stocke, lying heaps, or blocks. The orbicular masses often occur in the interior of un¬ stratified mountains, or in the bosom of one bed. JVcsfs, concretions, nodules, are small masses found in the middle of strata ; the first being commonly in a fria¬ ble state ; the second often kidney-shaped, or tuberous ; the third nearly round, and encrusted, like the kernel of an almond. Lodes, or large veins, are flattened masses, with their opposite surfaces not parallel, which consequently termi¬ nate like a wedge, at a greater or less distance, and do not run parallel with the rocky strata in which they lie, but cross them, in a direction not far from the perpendic¬ ular ; often traversing several different mineral planes. The lodes are sometimes dei’anged in their course, so as to pursue, tor a little way, the space between two con- MINES. 281 tiguous strata ; at other times they divide, into several branches. The matter which fills the lodes is, for the most part, entirely different from the rocks they pass through ; or, at least, it possesses peculiar features. This mode of existence, exhibited by several mineral substances, but which has been long known with regard to metallic ores, suggests the idea of clefts, or rents, having been made in the stratum, posterior {o its consolidation, and of the vacuities having been filled with foreign matter, either immediately, or after a certain interval. There can be no doubt, as to the justness of the first part of the proposition, for there may be observed, round many lodes, undeniable proofs of the movement or dislocation of the rock ; for example, upon each side of the rent, the same strata are no longer situated in the same plane as before, but make greater or smaller angles with it; or the stratum upon one side of the lode is raised considerably above, or depressed considerably below, its counterpart, upon the other side. With regard to the manner in which the rent has been filled, different opinions may be entertained. In the lodes which are widest, near the surface of the ground, and graduate into a thin wedge, below, the foreign matter would seem to have been introduced, as into a funnel, at the top, and to have carried along with it, in its fluid state, portions of rounded gravel and organic remains. In oth¬ er cases, other conceptions seem to be more probable ; since many lodes are largest, at their under part, and be¬ come progressively narrower, as they approach the sur¬ face ; from w'hich circumstance it has been inferred, that the rent has been caused by an expansive force, acting from within the earth, and that the foreign matter, having been injected in a fluid state, has afterwards slowly crys¬ tallized. This hypothesis accounts, much better than the other, for most of the phenomena observable in mineral veins, for the alterations of the rock at their sides, for the crystallization of the different substances interspersed in them, for the cavities bestudded wdth little crystals, and for many minute peculiarities. Thus, the large crystals of certain substances, which line the walls of hollow veins, have sometimes their under surfaces besprinkled with 24* 282 APPENDIX. small crystals of sulphurets, arseniurets, &c., while their upper surfaces are quite smooth ; suggesting the idea of a slow sublimation of these volatile matters from below, by the residual heat, and their condensation upon the under faces of the crystalline bodies, already cooled. This phe¬ nomenon affords a strong indication of the igneous origin of metalliferous veins. In the lodes, the principal matters which fill them are to be distinguished from the accessory substances ; the latter being distributed, irregularly, amidst the mass of the first, in crystals, nodules, veins, seams, &c. The non-metalliferoLis exterior portion, which is often the largest, is called gangue, from the German gang., vein. The position of a vein is denoted, like that of the strata, by the angle of inclination, and the point of the horizon towards which they dip, whence the direction is deduced. Veins are merely small lodes, which sometimes tra¬ verse the great ones, ramifying, in various directions, and in different degrees of tenuity. A metalliferous substance is said to be disseminated^ when it is dispersed in crystals, spangles, scales, globules, &c., through a large mineral mass. Certain ores, which contain the metals most indispensa¬ ble to human necessities, have been treasured up by the Creator in very bountiful deposits ; constituting either great masses in rocks of difterent kinds, or distributed in lodes, veins, nests, concretions, or beds, with stony and earthy admixtures ; the whole of which become the ob¬ jects of mineral exploration. These precious stones occur in different stages of the geological formations, but their main portion, after having existed, abundantly, in the sev¬ eral orders of the primary strata, suddenly cease to be found, towards the middle of the secondary. Iron ores are the only ones which continue among the more mod¬ ern deposits, even so high as the beds immediately beneath the chalk, when they also disappear, or exist merely as coloring matters of the tertiary earthy beds. The strata of gneiss and mica-slate constitute, in Eu¬ rope, the grand metallic domain. There is hardly any kind of ore, which does not occur there in sufficient abun- MINES. 283 dance, to become the object of mining operations, and many are found nowhere else. The transition rocks, and the lower part of the secondary ones, are not so rich, neither do they contain the same variety of ores. But this order of things, which is presented by Great Britain, Germany, France, Sweden, and Norway, is far from forming a general law ; since in Equinoctial America, the gneiss is but little metalliferous ; while the superior s>.rata, such as the clay-schists, the sienitic porphyries, the lime¬ stones, which complete the transition series, as also sev¬ eral secondary deposits, include the greater portion of the immense mineral wealth of that region of the globe. All the substances, of which the ordinary metals form the basis, are not equally abundant in Nature ; a great proportion of the numerous mineral sjiecies, which figure in our classifications, are mere varieties, scattered up and down in the cavities of the great masses, or lodes. The workable ores are few in number, being mostly sulphurets, some oxides, and carbonates. These occasionally form, of themselves, very large masses ; but, more frequently, they are blended with lumps of quartz,feldspar, and car¬ bonate of lime, which form the main body of the deposit ; as happens, always, in proper lodes. The ores, in that case, are arranged in small layers, parallel to the strata of the formation, or in small veins, which traverse the rock in all directions, or in nests, or concretions, stationed ir¬ regularly, or finally disseminated, in hardly visible parti¬ cles. These deposits sometimes contain, apparently, only one species of ore, sometimes several, which must be mined together, as they seem to be of contemporane¬ ous formation ; whilst, in other cases, they are separable, having been probably formed at dift'erent epochs. Lodes, or mineral veins, are usually distinguished, by English miners, into at least four species. 1. The rake- vein ; 2. The pipe-vein; 3. The flat, or dilated, vein ; and 4. The interlaced mass, (stock-werke,) indicating the union of a multitude of small veins, mixed, in every possi¬ ble direction, with each other and with the rock. 1. The rake vein is a perpendicular mineral fissure ; and is the form best known among practical miners. It 284 APPENDIX. commonly runs in a straight line, beginning at the super¬ ficies of the strata, and cutting them downwards, generally further than can be reached. This vein sometimes stands quite perpendicular ; but it more usually inclines, or hangs over, at a greater or smaller angle, or slope, which is called, by the miners, the hade, or hading, of the vein. The line of direction in which the fissure runs is called, the bearing of the vein. 2. The pipe vein resembles, in many respects, a huge, irregular cavern, pushing forward into the body of the earth, in a sloping direction, under various inclinations, from an angle of a few degrees to the horizon, to a dip of forty-five degrees, or more. The pipe does not, in general, cut the strata across, like the rake-vein, but insinuates itself between them ; so that, if -the plane of the strata be nearly horizontal, the bearing of the pipe-vein will be con¬ formable ; but if the strata stand up at a high angle, the pipe shoots down, nearly headlong, like a shaft. Some pipes are very wide and high, others are very low and narrow, sometimes not larger than a common mine, or drift. 3. The fat, or dilated, vein is a space or opening, be¬ tween two strata or beds of stone, the one of which lies above, and the other below, this vein, like a stratum of coal between its roof and pavement ; so that the vein and the strata are placed in the same plane of inclination. These veins are subject, like coal, to be interrupted, broken, and thrown up or down, by slips, dykes, or other interruptions of the regular strata. In the case of a me¬ tallic vein, a slip often increases the chance of finding more treasure. Such veins do not preserve the parallel¬ ism of their beds, characteristic f'f coal-seams ; but vary, excessively, in thickness, within a moderate space. Flat veins occur, frequently, in limestone, either in a horizontal or declining direction. The flat, or strata, veins open and close, as the rake-veins also do. To these may be added, the accumulated vein, or ir¬ regular mass, {butzenioerke,) a great deposit, placed, with¬ out any order, in the bosom of the rocks, apparently filling up cavernous spaces. MINES. 285 The interlaced masses are more frequent in primitive formations, than in the others, and tin is the ore which most commonly affects this locality. These gangues, such as quartz, calcareous spar, fluor spar, heavy spar, &c., and a great number of other sub¬ stances, although of little or no value in themselves, be¬ come of great consequence to the miner, either by point¬ ing out, by their presence, that of certain useful minerals, or by characterising, in their several associations, difler- ent deposits of ores, of which it may be possible to follow the traces, and to discriminate the relations, often of a complicated kind, provided we observe assiduously the accompanying gangues. Mineral veins are subject to derangements, in their course, which are called shifts, or faults. Thus, when a transverse vein throws out, or intercepts a longitudinal one, we must commonly look for the rejected vein on the side of the obtuse angle, which the direction of the latter makes with that of the former. When a bed of ore is deranged by a fault, we must observe, whether the slip of the strata be upwards or downwards ; for, in either circumstance, it is only by pursuing the direction of the fault, that we can recover the ore ; in the former case, by mounting, in the latter, by descending, beyond the dislocation. When two veins intersect each other, the direction of the offcast is a subject of interest, both to the miner and the geologist. In Saxony, it is considered as a general fact, that the portion thrown out is always upon the side of the obtuse angle, a circumstance which liolds also in Cornwall ; and the more obtuse the angle, the out-throw is the more considerable. A vein may be thrown out, on meeting another vein, in a line which approaches either towards its inclination, or its direction. The Cornish miners use two diflerent terms, to denote these two modes of rejection ; for the first case, they say the vein is heaved ; for the second, it is started. GENERAL OBSERVATIONS ON THE LOCALITIES OF ORES AND ON THE INDICATIONS OF METALLIC MINES. 1. Tin exists, principally, in primitive rocks, appearing 286 APPENDIX. either in interlaced masses, in beds, or as a constituent part of the rock itself, and, more rarely, in distinct veins. Tin ore is found indeed, sometimes, in alluvial land, filling up low situations between lofty mountains. 2. Gold occurs either in beds, or in veins, frequently in primitive rocks; though, in other formations, and par¬ ticularly in alluvial earth, it is also found. When this metal exists in the bosom of primitive rocks, it is partic¬ ularly in schists ; it is not found in serpentine, but it is met with in gray-wacke, in Transylvania. The gold of alluvial districts, called gold of washing, or transport, oc¬ curs, as well as alluvial tin, among the debris of the more ancient rocks. 3. Silver is found, particularly in veins and beds, in primitive and transition formations ; though some veins of this metal occur in secondary strata. The rocks, richest in it, are, gneiss, mica-slate, clay-slate, gray-wacke, and old alpine limestone. Localities of silver ore itself are not numerous, at least in Europe, among secondary forma¬ tions ; but it occurs in combination with the ores of cop¬ per, or of lead. 4. Copper exists in the three mineral epochas : 1. in primitive rocks, principally in the state of pyritous copper, in beds, in masses, or in veins; 2. in transition districts, sometimes in masses, sometimes in veins of copper py¬ rites ; 3. in secondary strata, especially in beds of cupre¬ ous schist. 5. Lead occurs, also, in each of the three mineral epo¬ chas ; abounding, particularly, in primitive and transition grounds, where it usually constitutes veins, and occasion¬ ally beds, of sulphuretted lead, (galena.) The same ore is found in strata, or in veins, among secondary rocks, as¬ sociated, now and then, with ochreous iron-oxide and cal¬ amine, (carbonate of zinc,) and it is sometimes dissemi¬ nated, in grains, through more recent strata. 6. Iron is met with, in four different mineral eras, but in different ores. Among primitive rocks, magnetic iron ore and specular iron ore occur chiefly in beds, some¬ times of enormous size ; the ores of red, or brown, oxide of iron (haematite) are found generally in veins, or, occa- MINES. 287 sionally, in masses with sparry iron, both in primitive and transition rocks ; as also, sometimes, in secondary strata ; but, more frequently, in the coal-measure strata, as beds of clay-ironstone, of globular iron-oxide, and carbonate of iron. In alluvial districts, we find ores of clay-iron¬ stone, granular iron-ore, bog-ore, swamp-ore, and mead¬ ow-ore. The iron ores, which belong to the primitive period, have almost always the metallic aspect, with a richtJBss amounting even to eighty per cent, of iron, while the ores in the posterior formations become, in general, more and more earthy, down to those in alluvial soils, some of which present the appearance of a common stone, and afford not more than twenty per cent, of metal, though its quality is often excellent. 7. jyiercury occurs principally among secondary stra¬ ta, in disseminated masses, along with combustible sub¬ stances ; though the metal is met with, occasionally, in primitive countries. 8. Cobalt belongs to the three mineral epochas ; its most abundant deposits are veins in primitive rocks. Small veins, containing this metal, are found, however, in secondary strata. 9. Antimony occurs in veins, or beds, among primitive and transition rocks. 10. 11. Bismuth and nickel do not appear to consti¬ tute tlK3 predominating substance of any mineral deposits ; but they often accompany cobalt. 12. Zinc occurs in the three several formations ; name¬ ly, as sulphuret or blonde, particularly in primitive and tran¬ sition rocks ; as calamine, in secondary strata, usually along with oxide of iron, and sometimes with sulphuret of lead. An acquaintance with the general results, collected and classified by geology, must be our first guide in the inves¬ tigation of mines. This enables the observer to judge, whether any particular district should, from the nature and arrangement of its rocks, be suscej)tible of including within its bosom, beds of workable ores. It indicates, also, to a certain degree, what substances may probably be met with in a given series of rocks, and what locality these substances will preferably affect. For want of a 288 APPENDIX. knowledge of these facts, many persons have gone blindly into researches, equally absurd and ruinous. Formerly, indications of mines were taken from very unimportant circumstances ; from thermal waters, the heat of which was gratuitously referred to the decomposition of pyrites ; from mineral waters, whose course is, howev¬ er, often from a far distant source ; from vapours incum¬ bent over particular mountain groups ; from the snows melting faster in one mineral district than another ;^rom the different species of forest trees, and from the greater or less vigor of vegetation, &c. In general, all such in¬ dications are equally fallacious with the divining rod, and the compass made of a lump of pyrites, suspended by a thread. Geognostic observation has substituted more rational characters of metallic deposits, some of which may be called negative, and others positive. The negative indications are derived from that peculiar geological constitution, which, from experience, or general principles, excludes certain metallic matters ; for example, granite, and, in general, every primitive formation, forbids the hope of finding within them combustible fossils, (pit- coal,) unless it be beds of anthracite ; there also it would be vain to seek for sal gem. It is very seldom that granite rocks include silver; or limestones, ores of tin. Volcanic territories never afford any metallic ores worth the work¬ ing ; nor do extensive veins usually run into secondary and alluvial formations. The richer ores of iron do not occur in secondary strata ; and the ores of this metal, peculiar to these localities, do not exist among primary rocks. Among positive indications, some are proximate, and others remote. The proximate are, an efflorescence, so to speak, of the subjacent metallic masses ; magnetic at¬ traction, for iron ores; bituminous stone, or inflammable gas, for pit-coal ; the frequent occurrence of fragments of particular ores, &c. The remote indications consist in the geological epocha and nature of the rocks. From the examples previously adduced, marks of this kind ac¬ quire new importance, when, in a district susceptible of including deposits of workable ores, the gangues, or vein- MINES. 289 stones, are met with, which usually accompany any partic¬ ular metal. The general aspect of mountains, whose flanks present gentle and continuous slopes, the frequency of sterile veins, the presence of metalliferous sands, the neighborhood of some known locality of an ore, for in¬ stance, that of iron-stone, in reference to coal ; lastly, the existence of salt springs and mineral waters may fur¬ nish some indications. In speaking of remote indications, we may remark, that, in several places, and particularly near Clausthal, in the Hartz, a certain ore of red oxide of iron occurs above the most abundant deposits of the ores of lead and silver ; whence it has been named by the Germans, the iron-kat. It appears that the iron ore, rich in silver, which is worked in America, under the name of pacos, has some analogy with this substance ; but iron ore is, in general, so plen¬ tifully diffused on the surface of the soil, that its presence can be regarded as only a remote indication, relative to other mineral substances, except in the case of clay-iron¬ stone wdth coal. Of the instruments and processes of subterranean op¬ erations. —It is by the aid of geometry, in the first place, that the miner studies the situation of the mineral depos¬ its, on the surface, and in the interior, of the ground ; de¬ termines the several relations of the veins and the rocks ; and becomes capable of directing the perforations tow^ards a suitable end. The instruments are, 1. The magnetic compass, which is employed to measure the direction of a metallic ore, wherever the neighborhood of iron does not interfere with its functions. 2. The graduated semicircle, which serves to measure the inclination, which is also called the cli¬ nometer. 3. The chain, or cord, for measuring the dis¬ tance of one point from another. 4. When the neighbor¬ hood of iron renders the use of the magnet uncertain, a j)late, or plane table, is employed. The dials of the compasses, generally used in the most celebrated mines, are graduated into hours ; most com¬ monly into twice twelve hours. Thus the whole limb is divided into twenty-four spaces, each of w'hich contains II. 2.5 xn. 290 APPENDIX. fifteen degrees, equal to one hour. Each hour is subdi¬ vided into eight parts. JVEeans of penetrating into the interior of the earth .— In order to penetrate into the interior of the earth, and to extract from it the objects of his toils, the miner has at his disposal several means, which may be divided into three classes ; 1. manual tools, 2. gunpowder, and 3. fire. The tools used by the miners of Cornwall and Devonshire are the following : The pick. It is a light tool, and somewhat varied in shape, according to circumstances One side, used as a hammer, is called the poll, and is employed to drive in the gads, or to loosen and detach prominences. The point is of steel, carefully tempered, and drawn under the ham¬ mer to the proper form. The French call it pointerolle. The gad. It is a wedge of steel, driven into crev¬ ices of rocks, or into small openings made with the point of the pick. The miner’’s shovel. It has appointed form, to ena¬ ble it to penetrate among the coarse and hard fragments of the mine rubbish. Its handle being somewhat bent, a man’s power may be conveniently applied, without bend¬ ing his body. The blasting, or shooting, tools are, a sledge or mallet, borer, claying-bar, needle or nail, scra¬ per, tamping-bar. Besides these tools, the miner requires a powder-horn, rushes to be filled with gunpowder, tin car¬ tridges, for occasional use in wet ground, and paper rubbed over with gunpowder, or grease, for the smifts, or fuses. The borer is an iron bar, tipped with steel, formed like a thick chisel, and is used by one man holding it straight in the hole, with constant rotation on its axis, while another strikes the head of it, with the iron sledge, or mallet. The hole is cleared out, from time to time, by the scraper, which is a flat iron rod, turned up at one end. If the ground be very wet, and the hole gets full of mud, it is cleaned out by a stick, bent at the end into a fibrous brush, called a swab-stick. The hole must be rendered as dry as possible, which is effected very simply, by filling it partly with tenacious clay, and then driving into it a tapering iron rod, which MINES. 291 nearly fills its calibre, called the claying-bar. This be¬ ing forced in with great violence condenses the clay into all the crevices of the rock, and secures the dryness of the hole. Should this plan fail, recourse is had to tin cartridges, furnished with a stem, or tube, through which the powder may be inflamed. When the hole is dry, and tlie charge of powder introduced, the nail, a small taper rod of copper, is inserted, so as to reach the bottom of the hole, which is now ready for tamping. By this difficult and dangerous process, the gunpowder is confined, and the disruptive effect produced. Different substances are employed for tamping, or cramming the hole, the most usual one being any soft species of rock, free from sili- cious, or flinty, particles. Small quantities of it only are introduced at a time, and rammed very hard, by the tamp- ing-bar, which is held steadily by one man, and struck with a sledge by another. The hole being thus filled, the nail is withdrawn, by putting a bar through its eye, and striking it upwards. Thus, a small perforation, or vent, is left for the rush which communicates the fire. Besides the improved tamping-bar, faced with hard cop¬ per, other contrivances have been resorted to, for dimin- ishing the risk of those dreadful accidents that frequently occur in this operation. Dry sand is sometimes used as a tamping material ; but there are many rocks, for the blasting of which it is ineffective. Tough clay will answer better, in several situations. For conveying the fire, tlie large and long green rushes, which grow in marshy ground, are selected. A slit is made in one side of the rush, along which the sharp end of a bit of stick is drawn, so as to extract the pith, when the skin of the rush closes again, by its own elasticity. This tube is filled up with gunpow¬ der, dropped into the vent-hole, and made steady with a bit of clay. A paper smift, adjusted to burn a proper time, is then fixed to the top of the rush tube, and kindled, when the men of tlie mine retire to a safe distance. Gunpowder is the most valuable agent of excavation ; possessing a power which has no limit, and w’hich can act every where, even under water. Its introduction, in 1G15, caused a great revolution in the mining art. 292 APPENDIX. It is employed in mines, in different manners, and in different quantities, according to circumstances. In all cases, however, the process resolves itself into boring a hole, and enclosing a cartridge in it, which is afterwards made to explode. The hole is always cylindrical, and is usually made by means of the borer, a stem of iron ter¬ minated by a blunt-edged chisel. It sometimes ends in a cross, formed by two chisels set transversely. The work¬ man holds the stem in his left hand, and strikes it with an iron mallet, held in his right. He is careful to turn the punch a very little round, at every stroke. Several punches are employed, in succession, to bore one hole; the first shorter, the latter ones longer, and somewhat thinner. The rubbish is withdrawn, as it accumulates at the bottom of the hole, by means of a picker, which is a small spoon, or disc of iron, fixed at the end of a slender iron rod. When holes of a large size are to be made, several men must be employed; one, to hold the punch, and one or more, to wield the iron mallet. The perforations are sel¬ dom less than an inch in diameter, and eighteen inches deep; but they are sometimes two inches wide, with a depth of fifty inches. The gunpowder, when used, is most commonly put up in paper cartridges. Into the side of the cartridge, a small cylindrical spindle^ or piercer, is pushed. In this state, the cartridge is forced down to the bottom of the hole, which is then stuffed, by means of the tamping-bar, with bits of dry clay, or friable stones coarsely pounded. The peircer is now withdrawn, which leaves in its place a channel, through which fire may be conveyed to the charge. This is executed, either by pouring gunpowder into that passage, or by inserting into it, reeds, straw-stems, quills, or tubes of paper, filled with gunpowder. This is explod¬ ed by a long match, which the workmen kindle, and then retire to a place of safety. As the piercer must not only be slender, but stiff, so as to be easily withdrawn when the hole is tamped, iron spindles are usually employed, though they occasionally give rise to sparks, and, consequently, to dangerous acci¬ dents, by their friction against the sides of the hole. Brass MINES. 293 piercers have been sometimes tried, but they twist and break too readily. Each hole bored in a mine should be so placed, in ref¬ erence to the schistose-structure of the rock, and to its natural fissures, as to attack and blowup the least resisting masses. Sometimes, the rock is prepared, beforehand, for splitting in a certain direction, by means of a narrow chan¬ nel, excavated with the small hammer. The quantity of gunpowder should be proportional to the depth of the hole, and the resistance of the rock ; and nferely sufficient to split it. Any thing additional would serve no other purpose than to throw the fragments about the mine, without increasing the useful effect.' Into the holes of about an inch and a quarter diameter, and eigh¬ teen inches deep, only two ounces of gunpowder are put. It appears, that the effect of the gunpowder may be augmented, by leaving an empty space above, in the mid¬ dle of, or beneath, the cartridge. In the mines of Sile¬ sia, the consumption of gunpowder has been eventually reduced, without diminishing the product of the blasts, by mixing sawdust with it, in certain proportions. The hole has also been filled up with sand, in some cases, ac¬ cording to Mr. Jessop’s plan, instead of being packed with stones, which has removed the danger of the tamp¬ ing operation. The experiments, made in this way, have given results very advantageous, in quarry blasts, with great charges of gunpowder ; but less favorable, in the small charges employed in mines. Water does not oppose an insurmountable obstacle to the employment of gunpowder ; but when the hole cannot be made dry, a cartridge bag, impermeable to water, must be used, provided with a tube, also impermeable, in which the piercer is placed. After the explosion of each mining charge, wedges and levers are employed, to drag away, and breakdown, what has been shattered. Wherever the rock is tolerably hard, the use of gun¬ powder is more economical, and more rapid, than any tool- work, and is, therefore, always preferred. A gallery, for example, a yard and a half high, and a yard wide, the 25* 294 APPENDIX. piercing of which, by the hammer, formerly cost from five to ten pounds sterling the running yard, in Germany, is executed, at the present day, by gunpowder, at from two to three pounds. When, however, a precious mass of ore is to be detached ; when the rock is cavernous, which nearly nullifies the action of gunpowder ; or when there is reason to apprehend that the shock, caused by the explo¬ sion, may produce an injurious fall of rubbish, band-tools alone must be employed. In certain rocks and ores, of extreme hardness, the use, both of tools and gunpowder, becomes very tedious and costly. Examples to this effect are seen in the mass of quartz, mingled with copper pyrites, worked at Rammels- burg, in the Hartz ; in the masses of stanniferous granite of Geyer and Altenberg, in the Erzgebirge of Saxony, &c. In these circumstances, fortunately very rare, the action of fire is used with advantage, to diminish the cohesion of the rocks and the ores. The employment of this agent is not necessarily restricted to these difficult cases. It was formerly applied, very often, to the working of hard substances ; but the introduction of gunpowder into the raining art, and the increase in the price of wood, occa¬ sion fire to be little used as an ordinary means of excava¬ tion, except in places,where the scantiness of the popula¬ tion has left a great extent of forest-timber, as happens at Kongsberg in Norway, at Dannemora in Sweden, at Fel- sobanya in Transylvania, &c. The action of fire may be applied to the piercing of a gallery, or to the advancement of a horizontal cut, or to the crumbling down of a mass of ore, by the successive upraising of the roof of a gallery already pierced. In any of these cases, the process consists in forming bonfires, the flame of which is made to play upon the parts to be attacked. All the workmen must be removed from the mine,during, and even for some time after, the combus¬ tion. When the excavations have become sufficiently cool to allow them to enter, they break down with levers and wedges, or even by means of gunpowder, the masses which have been rent and altered by the fire. To complete our account of the manner in which man MINES. 295 may penetrate into the interior of the earth, we must point out the form of the excavations that he should make in it. In mines, three principal species of excavations may be distinguished, viz.; shafts, galleries, and the cavities of greater or less magnitude, which remain in the room of the old workings. A shaft, or pit, is a prismatic, or cylindrical, hollow space, the axis of which is either vertical, or much inclin¬ ed to the horizon. The dimension of the pit, which is never less than tliirty-two inches in its narrowest diameter, amounts,sometimes,to several yards. Its depth may ex¬ tend to one thousand feet, and more. Whenever a shaft is opened, means must be provided to extract the rubbish, which continually tends to accumulate at its bottom, as well as the waters, which may percolate down into it; as also to facilitate the descent and ascent of the workmen. For some time a wheel and axle, erected over the mouth of the opening, which serve to elevate one or two buckets, of proper dimensions, may be sufficient for most of these purposes. But such a machine becomes, ere long, inad¬ equate. Horse-whims, or powerful steam-engines, must then be had recourse to ; and effectual methods of support must be employed, to prevent the sides of the shaft from crumbling, and falling down. A gallery is a prismatic space, the straight or winding axis of which does not usually deviate much from the hor¬ izontal line. Tw'o principal species are distinguished ; the galleries of elongation, which follow the direction of a bed, or a vein ; and the transverse galleries, which in¬ tersect this direction under an angle, not much different from ninety degrees. The most ordinary dimensions of galleries are a yard wdde, and two yards high ; but many, still larger, may be seen, transversing thick deposites of ore. There are few, whose width is less than tw'enty-four inches, and height less than forty; such small drifts serve merely as temporary expedients in workings. Some gal¬ leries are several leagues in length. We shall cescribe, in the sequel, the means which are, for the most part, necessary to support the roof and the walls. The rubbish is removed by wagons, or wheel-barrows, of various kind.« 29G APPENDIX. It is impossible to advance the boring of a shaft, or gal¬ lery, beyond a certain rate ; because only a limited set of Mmrkmen can be made to bear upon it. There are some galleries which have taken more than thirty years to perforate. The only expedient for accel¬ erating the advance of a gallery, is, to commence, at sev¬ eral points of the line to be pursued, portions of galleries, which may be joined together on their completion. Whether tools, or gunpowder, be used, in making the excavations, they should be so applied, as to render the labor as easy and quick as possible, by disengaging the mass out of the rock, at two or three of its faces. The effect of gunpowder, wedges, or picks, is then much more powerful. The greater the excavation, the more impor¬ tant is it to observe this rule. With this intent, the work¬ ing is disposed in the form of steps, (gradins,) placed like those of a stair ; each step being removed, in succes¬ sive portions, the whole of which, except the last, are disengaged on three sides, at the instant of their being at¬ tacked. The substances to be mined occur in the bosom of the earth, under the form of alluvial deposits, beds, pipe- veins or masses, threads or small veins, and rake-veins. When the existence of a deposit of ore is merely sus¬ pected, without positive proofs, recourse must be had to labors of research, in order to ascertain the richness, na¬ ture, and disposition, of a supposed mine. These are divided into three kinds ; open workings, subterranean workings, and boring operations. 1. The working by an open trench has for its object to discover the outcropping, or basset edges of strata, or veins. It consists in opening a fosse of greater or less width, which, after removing the vegetable mould, the alluvial deposits, and the matters disintegrated by the at¬ mosphere, discloses the native rocks, and enables us to distinguish the beds, which are interposed, as well as the veins which traverse them ; the trench ought always to be opened in a direction perpendicular to the line of the sup¬ posed deposit. This mode of investigation costs little, DEPTH OF MINES. 297 but it seldom gives much insight. It is chiefly employed for verifying the existence of a supposed bed, or vein. The subterranean workings afford much more satisfac¬ tory knowledge. They are executed by different kinds of perforations ; viz. by longitudinal galleries^ hollowed out of the mass of the beds or veins themselves, in fol¬ lowing their course ; by transverse galleries^ pushed at right angles to the direction of the veins ; by inclined shafts^ which pursue the slope of the deposits, and are excavated in their mass ; or, lastly, hy perpendicular pits. If a vein or hed unveils itself on the ffank of a moun¬ tain, it may be explored, according to the greater or less slope of its inclination, either by a longitudinal gallery, opened in its mass from the outcropping surface, or by a transverse gallery, falling upon it in a certain point, from which either an oblong gallery, or a sloping shaft, may be opened. If our object be to reconnoitre a highly inclined stra¬ tum, or a vein in a level country, we shall obtain it, with sufficient precision, by means of shafts, eight or ten yards deep, dug at thirty yards distance from one another, ex¬ cavated in the mass of ore, in the direction of its depo¬ sit. If the bed is not very much inclined, only forty-five degrees, for example, vertical shafts must be opened in the direction of its roof, or of the superjacent rocky stra¬ tum, and galleries must be driven from the points in which they meet the ore, in the line of its direction. When the rocks, which cover valuable minerals, are not of very great hardness, as happens generally with the coal formation, with pyritous and aluminous slates, sal gem, and some other minerals of the secondary strata, the bor¬ er is employed with advantage, to ascertain their nature. This mode of Investigation is economical, and gives, in such cases, a tolerably exact Insight into the riches of the interior. The method of using the borer has been de¬ scribed under Artesian Wells. — ?7re’s ‘ Diet, of Arts,'’ 4*c. III.— Depth of Mines. At the third meeting of the British Association, Mr. Taylor exhibited a section, showing the depths of shafts 298 APPENDIX. of the deepest mines in the world, and their position in relation to the level of the sea. The absolute depths of the principal ones were: Feet. 1. The shaft, called Roehrobichel, at the Kitspiihl mine, in the Tyrol,.2764 2. At the Sampson mine, at Andreasberg, in the Hartz,._2230 3. At the Valenciana mine, at Guanaxuato, Mexico.1770 4. Pearce’s shaft, at the Consolidated mines, Cornwall,. — 1464 5. At Wheal Abraham mine, Cornwall,.1452 6. At Dolcoath mine, Cornwall,.1410 7. At Ecton mine, Staffordshire,.1380 8. Woolf’s shaft, at the Consolidated mines,.1350 These mines are, however, very differently situated. with regard to their distance from the centre of the earth ; as the last on the list, Woolf’s shaft, at the Consolidated mines, has twelve hundred and thirty feet of its depth be¬ low the surface of the sea ; while the bottom of the shaft of Valenciana, in Mexico, is near six thousand feet in absolute height above the tops of the shafts in Cornwall. The bottom of the shaft, at the Sampson mine, in the Hartz, is but a few fathoms under the level of the ocean ; and this, and the deep mine of Kitspiihl, form, therefore, intermediate links between those of Mexico and Cornwall. Mr. Taylor stated, that, taking the diameter of the earth at eight thousand miles, and the greatest depth un¬ der the surface of the sea being twelve hundred and thir¬ ty feet, or about one fourth of a mile, it follows, that we have only penetrated to the extent of part of the earth’s diameter. IV.— Canals in the United States. The Americans have not rested satisfied with the nat¬ ural inland navigation afforded by their rivers and lakes, nor made the bounty of Nature a plea for idleness, or want of energy ; but, on the contrary, they have been zealously engaged in the work of internal improvement; and their country now numbers, among its many wonderful artifi¬ cial lines of communication, a mountain rail-way, which, in boldness of design, and difficulty of execution, I can compare to no modern works I have ever seen, except¬ ing, perhaps, the passes of the Simplon, and Mont Cenis, CANALS IN THE UNITED STATES. 299 in Sardinia ; but even these remarkable passes, viewed as engineering works, did not strike me as being more wonderful than the Alleghany rail-way, in the United States. The objects, to which that enterprising people have chiefly directed their exertions for the advancement of their country in the scale of civilization, are, the removal of ob¬ structions in navigable rivers ; the junction of different tracts of natural navigation ; the connection of large towns ; and the formation of lines of communication from the At¬ lantic ocean to the great lakes, and the valleys of the Mississippi, Missouri, and Ohio. The number and ex¬ tent of canals and rail-ways which they have executed, in effecting these important objects, sufficiently prove, that their exertions, during the short time they have been so engaged, have been neither small nor ill-directed. The aggregate length of the canals, at present in operation in the United States alone, amounts to upwards of two thou¬ sand seven hundred miles, and that of the rail-ways, already completed, to sixteen hundred miles. Nor are the labors of the people at an end ; for, even now, there are no few¬ er than thirty-three rail-ways in an unfinished state, whose aggregate length, when completed, will amount to upwards of two thousand five hundred miles. The zeal with which the Americans undertake, and the ra))idity with which they carry on, every enterprise, which has the enlargement of their trade for its object, cannot fail to strike all, who visit the United States, as a charac¬ teristic of the nation. Forty years ago, that country was almost without a lighthouse, and now, no fewer than two hundred are nightly exhibited on its coast; thirty years ago, it had but one steamboat, and one short canal, and now, its rivers and lakes are navigated by between five and six hundred steamboats, and its canals are upwards of two thousand seven hundred miles in length ; ten years ago, there were but three miles of rail-way in the country, and now, there are no less than sixteen hundred miles in oper¬ ation. 'fhese facts appear much more wonderful, when it is considered, that many of these great lines of commu¬ nication are carried for miles in a trough, as it were, cut 800 APPENDIX. through thick and almost impenetrable forests, where it is no uncommon occurrence to travel for a whole day, with¬ out encountering a village, or even a house, excepting, perhaps, a few log-huts, inhabited by persons connected with the works. The routes of the principal canals and rail-roads in North America are not wholly confined to the seaward and more thickly-peopled States, but extend far into the in¬ terior. The stupendous canals, which have already been executed, enable vessels, suited to the inland navigation of the country, to pass from the Gulf of St. Lawrence to the Gulf of Mexico, and also from the city of New York to Quebec, on the St. Lawrence, or to New Orleans, on the Mississippi, without encountering the dangers of the Atlantic ocean. But, that the reader may be able fully to understand the nature of lines of inland navigation, so enormous, I shall give, in detail, the route from New York to New Orleans, which is constantly made by per¬ sons travelling between those places. Miles. From New York to Albany, by the River Hudson, the dis¬ tance is, ....... . 150 “ Albany to Buffalo, by the Eric Canal, .... 363 “ Buffalo to Cleveland, by Lake Erie, .... 210 “ Cleveland to Portsmouth, by the Ohio Canal, . . 300 “ Portsmouth to New Orleans, by the Ohio and Mississippi Rivers, ........ 1670 Total distance, . . 2702 This extraordinary inland journey, of no less than two thousand seven hundred and two miles, is performed en¬ tirely by means of water-communication ; six hundred and seventy-two miles of the journey are performed on canals, and the remaining two thousand and thirty miles of the route is river and lake navigation. The internal improvements of the United States are placed under the management either of the Legislatures of the States, in which the works are situate, or of joint- stock companies. The works constructed by the Legis¬ latures of the States, are called State Works, and are conducted by commissioners, chosen from the different CANALS IN THE UNITED STATES. 301 Legislatures, who publish annual reports on the works committed to their charge. The joint-stock companies, on the other hand, are composed of private individuals, who receive a charter from the Government, investing them with power to execute the work, and afterwards to conduct the affairs and transact the business of the com¬ pany. The public works in the British dominions in North America have been executed, partly, at the ex¬ pense, and under the direction, of the British Govern¬ ment, and partly, by companies of private individuals. It is believed that canals, which were, until very lately, the only mode of conveyance employed in North Ameri¬ ca, were in use in Egypt, China, Ceylon, Italy, and Hol¬ land, before the Christian era ; but the period, at which the first artificial water-communication was formed, and the country, in which the construction of a canal was first attempted, are equally unknown. The earliest canal con¬ structed in France was the Languedoc, connecting the Bay of Biscay with the Mediterranean Sea, which was completed in the year 1681 ; and the first formed in Great Britain was that of Sankey Brook, in Lancashire, completed in 1760. Several short canals were made, for improving the river navigation, in the United States, about the end of the last century ; but the first work of any importance, in that country, was the Santee canal, in the State of South Carolina, which was opened in the year 1802 ; and the first, in the British dominions in Amer¬ ica, was the Lachine canal, in Lower Canada, opened in the year 1821. At the end of this chapter is a table of the principal canals in the United States. The table, which is compiled from the American almanacs, and the annual reports of the canal commissioners, contains the names of all the canals of any importance, now in opera¬ tion in the country ; together with such information, regard¬ ing their size and expense, as these documents contain. The great length of many of the American canals is one remarkable feature in these astonishing works. In this respect, they far surpass any thing of the kind hith¬ erto constructed in Europe. The longest canal in Eu¬ rope is the Languedoc, which has a course of one hun- II. 26 XII. 302 APPENDIX. dred and forty-eight miles ; and the most extensive in the United States is the Erie canal, which is no less than three hundred and sixty-three miles in length. But the cross-sectional area of the American canals is by no means so great as that of many in Europe. The North Holland Ship canal, for example, between the Zuyder Zee, at Amsterdam, and the Helder, which I lately visited, has a larger cross-sectional area, than any other European work of the same description. It measures one hundred and twenty-four feet six inches, at the water-line, and affords sufficient breadth to allow large vessels to pass each other with perfect ease. It is fifty-six feet in breadth, at the bottom, and has a depth of water of no less than twenty- one feet. This remarkable canal, which is nearly fifty miles in length, undoubtedly ranks as one of the greatest works of the kind that has ever been executed. It was constructed for the purpose of facilitating the passage of vessels to and from the port of Amsterdam ; and, by means of the sheltered inland passage which it affords, the intri¬ cate and dangerous navigation of the Zuyder Zee is avoid¬ ed. At the time when canals were introduced into Amer¬ ica, however, the trade of the country was small, and did not warrant the expenditure of large sums of money in their construction, the chief object being to form a com¬ munication, with as little loss of time, or outlay of capital, as might be consistent with a due regard for the safety and stability of the work. It is not to be expected, therefore, that the American works, although on an extensive scale, should be constructed in the same spacious style as those of older and more opulent countries. The dimensions of many of the canals in the United States are now found to be inconveniently small, for the increased traffic which they have to support; and the great Erie canal, as well as some others, is at present undergoing extensive altera¬ tions, by which its breadth will be increased from forty to sixty feet, and its depth from four to seven feet. It is doubtful whether the increased depth will, on the whole, prove advantageous, especially for quick transport. Ac¬ cording to Mr. Russell, the velocity of the wave due to a depth of four feet, making allowance for the sloping sides CANALS IN THE UNITED STATES. 303 of the canal, is about seven miles an hour; and if the boat is dragged in the top of the wave, the horses must travel at somewhat more than this rate, in order to keep before it. If, on the other hand, the depth of tlie canal be seven feet, the velocity of the wave will be about nine miles an hour ; a speed which it would be difficult for horses regular¬ ly to keep up. The boat would, consequently, travel at a less speed than the wave, which is shown by Mr. Rus¬ sell, in his ‘ Researches in Hydrodynamics,’ to be very disadvantageous. English and American engineers are guided by the same principles in designing their works ; but the differ¬ ent nature of the materials employed in their construc¬ tion, and the climates and circumstances of the two coun¬ tries, naturally produce a considerable dissimilarity in the practice of civil-engineers in England and America. At the first view, one is struck with the temporary and ap¬ parently unfinished state of many of the American works, and is very apt, before inquiring into the subject, to im¬ pute to want of ability what turns out, on investigation, to be a judicious and ingenious arrangement to suit the circumstances of a new country, of which the climate is severe,—a country,where stone is scarce, and wood is plentiful, and where manual labor is very expensive. It is vain to look to the American works for the finish, that characterizes those of France, or the stability, for which those of Britain are famed. Undressed slopes of cut¬ tings and embankments, roughly-built rubble-arches, stone parapet-walls coped with timber, and canal-locks whol¬ ly constructed of that material, every where ofiend the eye accustomed to view European workmanship. But it must not be supposed that this arises from want of knowl¬ edge of the principles of engineering, or of skill to do them justice in tlie execution. The use of wood, for example, which may be considered, by many, as wholly inapplicable to the construction of canal-locks, where it must not only encounter the tear and wear occasioned by the lockage of vessels, but must be subject to the destruc¬ tive consequences of alternate immersion in water and exposure to the atmosphere, is yet the result of deliber- 304 APPENDIX. ate judgement. The Americans have, in many cases, been induced to use the material of the country, ill adapt¬ ed though it be, in some respects, to the purposes to which it is applied, in order to meet the wants of a ris¬ ing community, by speedily, and perhaps superficially, completing a work of importance, which would otherwise be delayed, from a want of the means to execute it in a more substantial manner ; and, although the works are wanting in finish, and even in solidity, they do not fail for many years to serve the purposes for which they were constructed, as efficiently as works of a more lasting de¬ scription. When the wooden locks on any of the canals begin to show symptoms of decay, stone structures are generally substituted ; and materials, suitable for their erection, are with ease and expedition conveyed from the part of the country where they are most abundant, by means of the (janal itself to which they are to be applied ; and thus the less substantial work ultimately becomes the means of facilitating its own improvement, by affording a more easy, cheap, and speedy transport of those durable and expensive materials, without the use of which, perfection is unattainable. One of the most important advantages of constructing the locks of canals, in new countries, such as America, of wood, unquestionably is, that, in proportion as improve¬ ment advances, and greater dimensions, or other changes, are required, they can be introduced at little cost, and without the mortification of destroying expensive and substantial works of masonry. Some of the locks on the great Erie canal are formed of stone; but, had they all been made of wood, it would, in all probability, have been converted into a ship-canal,long ago. But the locks are not the only parts of the American canals in which wood is used. Aqueducts, over ravines or rivers, are generally formed of large wooden troughs, resting on stone pillars ; and even more temporary expe¬ dients have been chosen, the ingenuity of which can hard¬ ly fail to please those who view them as the means of carrying on improvements, which, but for such contriv- CANALS IN THE UNITED STATES. 305 ances, might be stopped by the want of funds necessary to complete them. Mr. M’Taggart, the resident engineer for the Rideau canal in Canada, gave a good example of the extraordi¬ nary expedients often resorted to, by suggesting a very novel scheme for carrying that work across a thickly wooded ravine, situate in a part of the country where materials for forming an embankment, or stone for build¬ ing the piers of an aqueduct, could not be obtained but at a great expense. The plan consisted of cutting across the large trees in the line of the works, at the level of the bottom of the canal, so as to render them fit for sup¬ porting a platform on their trunks, and on this platform the trough containing the water of the canal was intended to rest. I am not aware whether this plan was carried into effect ; but it is not more extraordinary than many of the schemes to which the Americans have resorted, in con¬ structing their public works ; and the great traffic sus¬ tained by many of them, notwithstanding the temporary and hurried manner in which they are finished, is truly wonderful. The number of boats navigating the Erie canal, in 1836, was no less than three thousand one hun¬ dred and sixty-seven, and the average number of lockages, one hundred and eighteen per day ; facts which clearly prove the efficiency, as well as the utility, of the work. With the exception of some few works, in the most southern States of the Union, the artificial navigation of North America, as well as that of the northern rivers and lakes, is completely suspended during a period of from three to five nronths, every year. During that time, the water is always withdrawn from the canals and feed¬ ers. This precaution is absolutely necessary, as the in¬ tense frost,with which the country is then visited, very soon proves destructive to the locks and aqueducts, by the expansion of the water, which, if permitted to re¬ main in them, is speedily converted into a mass of ice. The rate of travelling, which has been adopted on the American canals, the charges for the conveyance of passengers and goods, and the general laws for regulating canal transport, are fixed by the commissioners who have 26* 30G APPENDIX. charge of the different works, and are not exactly the same in every State. The following observations, how¬ ever, regarding the mode of travelling on the Pensylva- nia State canals, are generally applicable to all others in the country. The tolls paid to the State, by the persons who have boats on these canals, are three halfpence per mile for each boat, and three farthings per mile for each passenger conveyed in them. The passenger-boats vary from twelve to fifteen feet in breadth, and are eighty feet in length ; the large-sized boats weigh about twenty tons, and cost £250 each, and, when loaded with a full complement of passengers, draw twelve inches of water. They are dragged by three horses at once, which run ten-mile sta¬ ges. The length of the tow-line, generally used, is about one hundred and fifty feet, and the rate of travelling is from four to four and a half miles per hour. The works, which have been employed in forming the inland lines of water-communication in America, are of two kinds, called slackwater-navigation, and canals. The slackwater-navigation is the more simple of these operations, and can generally be executed at less expense. It consists in improving the navigation of a river by the erection of dams, or mounds, built in tlie stream, which have the effect of damming up the water, and increasing its depth. If there be not a great fall in the bed of the river, a single dam often produces a stagnation in the run of the water, extending for many miles up the river, and forming a spacious navigable canal. The tow-path is formed along the margin of the river, and is elevated above the reach of flood-water. The dams are passed by means of locks, such as are used in canals. This method of forming water-communication, has been extensively and successfully introduced in America, where limited means, and abundance of rivers, rendered it peculiarly applicable. One of the most extensive works, on this principle, in the country, was constructed by the Schuylkill Navigation Company, in the State of Pennsylvania, and consisted in damming up the water of the river Schuylkill. It ex¬ tends from Philadelphia to Reading, and is situate in the CANALS IN THE UNITED STATES. 307 heart of a country abounding in coal, from the transport of which, the Company derives its chief revenue. It is one hundred and eight miles in length, and its construc¬ tion cost about £500,000. This line of navigation is formed by numerous dams thrown across the stream, with twenty-nine locks, which overcome a fall of six hundred and ten feet. It is navigated by boats of from fifty to sixty tons burden. These dams are constructed some¬ what on the same principle as that erected on the Schuyl¬ kill, at Fairmount Water-works, near Philadelphia. One great objection, to this mode of forming inland navigation, is the necessity of constructing works of great strength, sufficient to enable them to withstand the floods and ice, to which they are exposed, and by which they are very apt to be damaged, or even carried away. Acci¬ dents of this kind, however, may be in a great measure guarded against, by making a judicious selection of situa¬ tions for the dams and locks, and placing them in such a manner in the bed of the river, that the current may act on them in the direction least detrimental to their sta¬ bility, as has been done in the dam at B'airmount Water¬ works, just alluded to. The number of boats, which passed through the locks of the Schuylkill navigation, in 1836, was twenty-four thousand four hundred and seventy, the tolls on which amounted to £14,043. The various articles taken up the river, during that year, weighed sixty-one thousand and seventy-nine tons, and those brought towards the sea, five hundred and seventy thousand and ninety-four tons, of which four hundred and thirty-two thousand and forty-five tons were anthracite coal, from the State of Pennsylvania. Slackwater-navigation also occurs at intervals on many of the great lines of canal. About seventy-eight miles of the Rideau canal, in Canada, are formed in this way ; and in the United States, it is met with on the Erie, Oswego, Pennsylvania, Frankston, Lycoming, and Lehigh canals. The works which have been executed, in forming most of the water-communications, in America, however, are not generally of the slackwater kind, but resemble the canals in use in Europe, being, in fact, artificial trenches 308 APPENDIX. or troughs, with locks to enable vessels to pass from one evel to another. The locks are furnished with boom- gates, which are opened and shut by a long lever fixed to the tops of the quoin and mitre posts. The sluices, by which the water is admitted into the locks, are placed in the lower part of the gates. They are, in general, com¬ mon hinge-sluices, opened by means of a rod extending to the top of the gates, and worked by a crank handle. The canals of this construction, in the United States, are so very numerous, and resemble each other so much, that I do not consider it necessary to give a detailed de¬ scription of the various works which have been executed on all of them, but shall content myself with giving a brief sketch of the Erie canal, which was the first in America, on which the conveyance of passengers was attempted, and is the longest canal in the world, regarding which we possess accurate information. The Erie canal was commenced in 1817, and com¬ pleted in 1825. The main line, leading from Albany, on the Hudson, to Buftalo, on Lake Erie, measures 363 miles in length, and cost about £1,400,000 sterling. The Champlain, Oswego, Chemung, Cayuga, and Crook¬ ed Lake, canals, and some others, join the main line, and, including these branch canals, it measures five hun¬ dred and forty-three miles in length, and cost upwards of £2,300,000. This canal is forty feet in breadth, at the water line, twenty-eight feet, at the bottom, and four feet in depth. Its dimensions have proved too small for the extensive trade which it has to support, and workmen are now employed in raising its banks, so as to increase the depth of water to seven feet, and the extreme breadth of the canal to sixty feet. The country through which it passes, is admirably suited for canal-navigation, and there are only eighty-four locks on the main line. These locks are each ninety feet in length, and fifteen in breadth, and have an average lift of eight feet two inches. The total rise and fall is six hundred and ninety-two feet. The tow-path is elevated four feet above the level of the water, and is ten leet in breadth. The Erie canal begins at Buffalo, on Lake Erie, and extends for a distance of CANALS IN THE UNITED STATES. 309 about ten miles along the banks of Lake Erie and the river Niagara, as far as Tonawanda creek. By means of the slackvvater-navigation, formerly described, the channel of the Tonawanda is rendered navigable for the distance of twelve miles, and the canal is then carried through a deep cutting, extending seven and a half miles, to Lockport. Here it descends sixty feet, by means of five locks excavated in solid rock, and afterwards pro¬ ceeds, on a uniform level, for a distance of sixty-three miles, to Genesee river, over which it is carried on an aqueduct having nine arches, of fifty feet span, each. Eight and a half miles from this point, it passes over the Cayuga marsh, on an embankment two miles in length, and, in some places, seventy feet in height. It then passes through Lakeport and Syracuse, and, at this place, the “ long level” commences, which extends for a distance of no less than sixty-nine and a half miles, to Frankfort, without an intervening lock. After leaving Frankfort, the canal crosses the river Mohawk, first by an aqueduct, of seven hundred and forty-eight feet in length, supported on sixteen piers, elevated twenty-five feet above the sur¬ face of the river, and afterwards, by another aqueduct, one thousand one hundred and eighty-eight feet in length, and at last reaches the city of Albany. Albany is the capital of the State of New York, and con¬ tains a population of about thirty thousand. It is situate on the west, or right, bank of the Hudson, at the head of the natural navigation of the river ; but some improve¬ ments have been made, which enable vessels of small burden to ascend as far as Waterford, thirteen miles above Albany. One of these improvements has been eflected by the erection of a dam across the Hudson, eleven hundred feet in length, and nine feet in height, at a cost of up¬ wards of 8,000. The lock, connected with this dam, measures one 'hundred and fourteen feet in length, and thirty feet in breadth. Albany, however, may be said to monopolize the trade of the river, and, in addition to the interest it possesses as a place of great commerce, it is important from its position at the outlet of the Erie canal, and as the seat of a large basin, or depot, for the 310 appendix. accommodation of the boats navigating it. This basin, which has an‘area of thirty-two acres, is formed by an enormous mound, placed lengthwise with the stream of the river Hudson, and enclosing a part of its surface. The mound is composed, chiefly, of earth, and is four thousand three hundred feet in length, and eighty feet in breadth, and, being completely covered with large ware¬ houses, it now forms a part of the city of Albany, with which it is connected by means of numerous drawbridges. The place has, in consequence, very much the same ap¬ pearance as many of the Dutch towns. The lower ex¬ tremity of the mound is unconnected with the shore, a large passage being left for the ingress and egress of ves¬ sels ; but its upper end is separated from the bank of the river, by a smaller opening, which is closed, when necessary, to prevent ice from injuring the craft lying in the basin. A stream of water is generally allowed to entep at the upper end, which, flowing through the basin, acts as a scour, and prevents it from silting up. The mound is surrounded by a wooden wharf, like those of New York and Boston, at which vessels discharge and load their cargoes. This admirable basin forms a part of the Erie canal works, and cost about £26,000. According to the Report of the Canal Commissioners, dated March, 1837, the number of boats, registered in the Comptroller’s ofiice, as navigating the Erie canal and its branches, was. In 1834, “ 1835, “ 1836, 2,585 2,914 3,167 Increase, 329 “ 253 The total number of clearances, or trips made during the same years, was, In 1834, . 64,794 “ 1835, . 69,767 “ 1836, . 67,270 The average number of lockages, per day, at each lock was. In 1834, “ 1835, “ 1836, 95 ^ 112 118 CANALS IN THE UNITED STATES. 311 The whole tonnage, transported on the canal, during the year 1836, was 1,310,807 tons, the value of which amounted to $67,643,343, or £13,526,868. The pro¬ portion between the weight of freight, conveyed from the Hudson to the interior of the country, and that con¬ veyed from the interior of the country to the Hudson, was in the ratio of one to five. The tolls, collected in 1836, for the conveyance of goods and passengers, amounted to £322,867. The rates of charge, accord¬ ing to which the tolls are collected, are annually changed, to suit the circumstances of the trade, and are not the same throughout the whole line of the canal, which ren¬ ders it difficult to give a view of them. In 1836, the passage-money from Albany to Bufi'alo, in the packet- boat, was £3 35., being at the rate of nearly 2d. per mile ; and in a line-boat, which is an inferior conveyance, £1 185., being at the rate of one penny and two tenths per mile. The expenditure for keeping the canal and its branches in repair, during 1836, was $410,236, or about £82,047 ; which, taking the whole length at five hundred and forty-three miles, gives an average of £151 per mile. The average cost of repairs, for the six preceding years, amounted to £136 ]ier mile. Before leaving the subject of canals, I must not omit to mention the Morris canal, in the State of New Jer¬ sey. This canal leads from Jersey, on the Hudson, to Easton, on the Delaware, and connects these two rivers. The breadth, at the water line, is thirty-two, and at the bottom, sixteen, feet, and the depth is four feet. It is one hundred and one miles in length, and is said to have cost about £600,000. It is peculiar, as being the only canal in America, in which the boats are moved from dif ferent levels by means of inclined planes, instead of locks , a construction, which was first introduced on the Duke of Bridgew’ater’s canal, in England. The whole rise and fall, on the Morris canal, is one thousand five hundred and fifty-seven feet, of which two hundred and twenty- three feet are overcome by locks, and the remaining one thousand three hundred and thirty-four feet, by means of twenty-three inclined planes, having an average lift of 312 APPENDIX. fifty-eight feet each. The boats, which navigate this canal, are eight and one half feet in breadth of beam, from sixty to eighty feet in length, and from twenty-five to thirty tons burden. The greatest weight ever drawn up the planes is about fifty tons. The boat-car used on this canal, consists of a strongly made wooden crib, or cradle, on which the boat rests, supported on two iron wagons running on four wheels. When the car is wholly supported on the inclined plane, or is resting on a level, the four axles of the wagons are all in the same plane ; but when one of the wagons rests on the inclined plane, and the other on the level surface, their axles no longer remain in the same plane, and their change of position produces a tendency to rack the cradle, and the boat which it supports ; but this has been guarded against, in the construction of the boat-cars on the Morris canal, by introducing two axles, on which the whole weight of the crib and boat are supported, and on which the wagons turn, as a centre. The cars run on plate-rails, laid on the inclined planes, and are raised and lowered by means of machinery driven by water-wheels. The rail-way, on which the car runs, extends for a short distance from the lower extremity of the plane, along the bottom of the canal. When a boat is to be raised, the car is lowered into the water, and the boat being floated over it, is made fast to the part of the framework which projects above the gunwale. The machinery is then put in motion ; and the car, bearing the boat, is drawn by a chain to the top of the inclined plane, at which there is a lock for its recep¬ tion. The lock is furnished with gates, at both extremi¬ ties ; after the car has entered it, the gates next the top of the inclined plane are closed, and, those next the canal being opened, the water flows in and floats the boat ofF the car, when she proceeds on her way. Her place is supplied by a boat travelling in the opposite direction, which enters the lock, and the gates next the canal being closed, and the water run off, she grounds on the car. The gates next the plane are then opened, the car is gen¬ tly lowered to the bottom, when it enters the water, and the boat is again floated. The principal objection, urged CANALS IN THE UNITED STATES. 313 against the use of inclined planes, in canal navigation, for moving boats from dilFerent levels, is founded on the in¬ jury which the boats are apt to sustain in supporting great weights, while resting on the cradle, during its passage over the planes. It can hardly be supposed that a slim- ly-built canal-boat, measuring from sixty to eighty feet in length, and loaded with a weight of twenty or thirty tons, can be grounded, even on a smooth surface, without strain¬ ing and injuring her timbers ; a circumstance which is a decided objection to this mode of construction, and has operated powerfully in preventing its introduction in many situations, both in this country and in America. But, notwithstanding this objection, the twenty-three inclined planes on the 5lorris canal are in full operation, and act exceedingly well. No pains have been spared to render the machinery connected with them as perfect as possible, and the greatest credit is due to the engineer for the suc¬ cess which has hitherto attended the operation.— Steven¬ son's ‘ Sketches of Civil Engineering in J^Torth America.' 27 11 . XII. TABLE of the Principal Canals and Lines of Slack-water Navigation, constructed in the United States, up to the year 1840, inclusive. Compiled from the Reports of the Canal Companies, the American Almanac, and other sources. 314 APPENDIX. a CU s o O o o w o pQ n3 o o o X o a o a> Xi o > cd JS <« ^ c o cn C4 0> 05 00 00' o 00 00 00 • •i-° 09 S w ^ H © c 03 © 2 •O u © > cd & »• c2 CO Ui PS a o 50 ^ Cd d s CO cu A © ■S fa CO & .2 ® ©*'15 ^ d^ © 00 (fa s '2 © u u <} ^ o S X © cd « (d cd u Pi o 09 o.^° > a d o 7) • © ■< CO 73 ^00 ■^ © - 2 S ® «2 .oj 2 2 - l-s § c V) fa Z O s © .d d o * OJ O -a ^ u ■*! ^ cd ew ess o S3 d c d fc. a £ ^ s ° s« t . ^ O d o cd A •J o H s fa o CO u s w © o $ I i« .S g •si o fi o .2 cd flS u o ® a. • o 2 ® w : J o = o ,Q Q ■ S 0) 03 © §S.2 ; C O 3-0 O ' H © - Iz: >• o . C3 cd 'Sc l> XI ^ s ® 5 o S o 3 OCD cd a '£ © d o S •. •2 2 c 2 « Cd d U CANALS IN THE UNITED STATES 315 < i 316 APPENDIX. CANALS IN THE UNITED STATES 317 27 * 318 APPENDIX. V.— Rail-ways in the United States. Within a very few years, a wonderful change has been effected in land-communication throughout Great Brit¬ ain and America, where rail-ways have been more ex¬ tensively and successfully introduced than in any other parts of the world. As early as the sixteenth century, wooden tram-roads were used in the neighborhood of many of the collieries of Great Britain. In the year 1767, cast-iron rails were introduced at Colebrookdale, in Shropshire. In 1811, malleable iron rails were, for the first time, used in Cumberland, and the locomotive en¬ gine, on an improved construction, was successfully in¬ troduced on the Liverpool and Manchester line, in 1830. Little progress has hitherto been made in the formation of rail-ways on the Continent of Europe. A small one has been in existence, for some time, in the neighborhood of Lyons ; but the only rail-road, constructed in France, for the conveyance of passengers by locomotive power, is that ’from Paris to St. Germains, which was opened only in 1837. In Bohemia, the Chevalier Gerstner, about eight years ago, constructed a rail-way of eighty miles in length, leading from the river Muldau to the Dan¬ ube. In Belgium, the rail-way from Antwerp to Ghent has been in use for some time ; and some lines are at pres¬ ent being constructed in Holland and Russia. But the purpose of the present article is to describe the state of this wonderful improvement in communication, in the United States. The Quincy rail-road, in Massachusetts, was the first constructed in America. It was intended for the con¬ veyance of stone from the Quincy granite-quarries to a shipping port, on the river Neponset, a distance of about four miles. At the end of this article is given a tabular list of the principal rail-roads which are already finished, and also of those that have been begun in the United States, which show the rapid increase of these works since 1827, the date at whi,ch the Quincy rail-road was completed. From these tables it appears that, in 1840, there were no fewer than seventy-one rail-ways completed. RAIL-WAYS IN THE UNITED STATES. 319 and in full operation, whose aggregate length amounts to about twenty-three hundred miles; and also, that twenty- three rail-ways were then in progress, which, when com¬ pleted, will amount to about twenty-eight hundred miles. In addition to this, upwards of one hundred and fifty rail¬ way companies have been incorporated ; and the works of many of them will, in all probability, be very soon commenced. The Boston and Lowell rail-way, in Massachusetts, is twenty-six miles in length, and is laid with a double line of rails. The breadth between the rails, which is four feet eight and a half inches, is the same in all the Ameri¬ can rail-roads, and the breadth between the tracks is six feet. The supporters are granite blocks, six feet in length, and about eighteen inches square. These are placed transversely, at distances of three feet apart, from centre to centre, each block giving support to both of the rails. This construction was first introduced in the Dublin and Kingstown rail-way, in Ireland, but was found to pro¬ duce so rigid a road, that great difficulty was experienced in securing the fixtures of the chairs. From the difficulty, also, of procuring a solid bed for stones of so great di¬ mensions, most of them, after being subjected for a slmrt lime to the traffic of the rail-way, were found to be split. Another construction has been tried on this line, con¬ sisting of longitudinal trenches, two feet six inches square, and four feet eight and a half inches apart, from centre to centre, formed in tlie ground, and filled with broken stone, hard punned down with a wooden beater, as a foundation for the stone blocks on which the rails rest. These blocks measure two feet square, and a foot in thickness, and a transverse sleeper of wood, two feet eight inches and a half in length, one foot in breadth, and eight inches in thickness, is placed between the blocks, to prevent them from moving. The plan of resting the rail-way on a foundation of brok¬ en stone was adopted, in the expectation that it might be sunk to a sufficient depth below the surface of the ground, to prevent the frost from affecting it; but subsequent 320 APPENDIX. experience has shown that many of those rail-ways, whose construction was more superficial, have resisted the ef¬ fects of frost much better. The New York and Patterson rail-way is sixteen and a half miles in length, and extends along a marshy tract of ground. The foundation of the road consists of a line of pits under each rail, eighteen inches square, and three feet in depth. They are placed three feet apart, from centre to centre, and filled with broken stones. On this foundation, transverse wooden sleepers, measuring eight inches square, and seven feet in length, are firmly bedded, on which rest the longitudinal sleepers, measur¬ ing eight inches by six. To these, plate-rails of mallea¬ ble iron, two and a half inches wide, and half an inch thick, weighing about thirteen pounds per lineal yard, are fixed by iron spikes. In the Saratoga and Schenectady rail-way, the paral¬ lel trenches are eighteen inches square, and four feet eight and a half inches apart, from centre to centre. They extend throughout the whole line of the rail-vyay, and are firmly punned full of broken stones. Longitudinal sleep¬ ers of wood, measuring eight by five inches, are placed on these trenches, which support the transverse wooden sleepers, measuring six inches square, and placed three feet apart, from centre to centre. Longitudinal runners, measuring six inches square, are firmly spiked to the transverse sleepers, and the whole is surmounted by a plate-rail, half an inch thick, and two and a half inches wide, weighing about thirteen pounds per lineal yard. The Newcastle and Frenchtown rail-way, which is sixteen miles in length, and forms part of the route from Philadelphia to Baltimore, is constructed in the same way as that between Schenectady and Saratoga, excepting that the plate-rail is two and a half inches broad, and five eighths of an inch thick, and weighs nearly sixteen pounds per lineal yard. The Baltimore and Washington rail¬ way is also constructed in the same manner, as regards the foundation and arrangement of the timbers ; but ^ge-rails are employed on that line, three and a half inches in breadth at the base, and two inches in height. RAIL-WAYS IN THE UNITED STATES. 321 Several experiments have been made on the Columbia rail-road, in Pennsylvania, which is eighty-two miles in length, and is under the management of the State. Part of the road is constructed with trenches measuring two feet six inches in breadth, and two feet in depth, excava ted in the ground, and filled with broken stone. In these, the stone blocks, two feet square, and a foot in thickness, are imbedded, at distances of three feet apart, to which the chairs and rails are spiked, in the ordinary manner. The rails on each side of the track are connected togeth¬ er by an iron bar. This attachment is rendered absolute¬ ly necessary, on many parts of the Columbia rail-road, by the sharpness of the curves, which, at the time when the work was laid out, were not considered so prejudicial on a rail-way, as experience has shown them to be. Another plan tried on this road has a continuous line of stone curb, one foot square, resting on a stratum of broken stone, instead of the isolated stone blocks. A plate-rail, half an inch thick, and two and a half inches broad, is spiked down to treenails, of oak or locust wood, driven into jumper-holes bored in the stone curb. The Boston and Providence rail-way is forty-one miles m length. Pits, measuring eighteen inches square, and one foot in depth, are excavated under each line of rail, at intervals of four feet apart. They are filled with broken stone, and form a foundation for the transverse wooden sleepers, measuring eight inches square, on which the chairs and rails are fixed in the usual manner. One of the tracks, in very general use in America, is met with on the Philadelphia and Norristown, the New York and Ilaerlemand the Buffalo and Niagara rail-roads : and has been introduced on manv oiiiers. It consists of two iines of longitudinal wooden runners, measuring one foot in breadth, and from three to four inches in thickness, bedded on broken stone, or gravel. On these runners, transverse sleepers are placed, formed of round timber, with the bark left on, measuring about six indies in diameter, and squared at the ends, to give them a prop¬ er rest. Longitudinal sleepers, for supporting the rails, are notched into the transverse sleepers. The rail is flat. 322 APPENDIX. made of wrought-iron, and varies in weight from ten to fif¬ teen pounds per lineal yard. It is fixed down to the sleep¬ ers, at every fifteen or eighteen inches, by spikes four or five inches in length, the heads of which are countersunk in the rail. The rails used on the Camden and Amboy rail-way, which is sixty-one miles in length, are parallel edge-rails, and are spiked to transverse sleepers of wood, and, in some places, to wood treenails driven into stone blocks. Their breadth is three and a half inches at the base, and two and a half at the top, and their height is four inches. They are formed in lengths of fifteen feet, and secured at the joints by an iron plate on each side, with two screw- bolts passing through the plates and rails. On the Phila¬ delphia and Reading rail-road, rails of the same form have been adopted. On several of the rail-roads, with a view to counteract the effects of frost, round piles of timber, about twelve inches in diameter, are driven into the ground as far as they will go, at the distance^of three feet apart, from cen¬ tre to centre. The tops are cross-cut, and the rails are spiked to them in the same way as in the Camden and Amboy Rail-way. The heads of the piles are furnished with an iron strap, to prevent them from splitting ; and the rails are connected together, at every five feet, by an iron bar. The Brooklyn and Jamaica rail-road is exceedingly smooth, and is said to resist the effects of frost very suc¬ cessfully. It consists of transverse sleepers, measuring eight by six inches, supported on slabs of pavement, two feet square, and six inches thick. The wooden runner IS spiked on the inside of the chairs, to render them firm. This rail rests on the cheeks^ or sides, of me cnair, ana not on the bottom, as is generally the case. The rail-road between Charleston and Augusta, and many others in the southern States, where there is a scar¬ city of materials for forming embankments, are carried over low-lying tracts of marshy ground, elevated on struc¬ tures of wooden truss-work. The framing is used m sit¬ uations where the level of the rails does not require to be RAIL-WAYS IN THE UNITED STATES. 323 raised more than ten or twelve feet above the surface of the ground. Piles,from ten to fifteen inches in diameter, are driven into the ground by a piling engine, and, in places where the soil is soft, their extremities are not pointed, but are left square, which makes them less liable to sink under the pressure of the carriages. The struts are attached to the tops of the piles, and are also fixed to dwarf piles driven into the ground. Their effect is to prevent lateral motion. It is evident, however, that these structures are by no means suitable or safe, for bearing the weight of locomotive engines or carriages ; and, as may naturally be expected, very serious accidents have occasionally occurred on them. They are, besides, gen¬ erally left quite exposed, and, in some situations, when they are even so much as twenty feet high, no room is left for pedestrians, who, if overtaken by the en¬ gine, can save themselves only by making a leap to the ground. These varieties of construction were all in use in the United Slates in 1837 ; but the American engineers had not, at that time, come to any definite conclusion, as to which of them constituted the best rail-way. It seemed to be generally admitted, liowever, that the wooden struc¬ tures were, in most situations, more economical than those formed of stone, and were also less liable to be affected by the frost. Structures of wood also possess a great advantage over tliose of stone, from the much greater ease with which the rails supported by them are kept in repair. Wooden rail-roads are more elastic, and bend under great weights, while the rigid and unyielding nature of the rail¬ roads laid on stone blocks causes the impulses, producea by the rapid motion of locomotive carriages, or heavily loaded w'agons, over the surface, to be much more severe¬ ly felt, both by the machinery of the engine, and by the rails themselves. Experience, both in this country and in America, has shown the trutli of these remarks. On the Liverpool and Manchester rail-way, for example, on which a large sum is annually expended in keeping the rails in order, the part of the road wdiich requires least repair is that extending over Chat Moss, where the rails are laid 324 APPENDIX. on wooden sleepers, and the weight of passing trains ol loaded wagons produces a sensible undulation in the sur¬ face of the rail-way, which at this place actually floats on the moss. These considerations are worthy of attention ; and, since the introduction of Kyan’s patent anti-dry-rot preparation, wood is beginning to be more generally em¬ ployed for the construction of rail-ways in this country. The rails of the Dublin and Kingstown road are now laid on wood, and it has also been extensively employed on the Great Western rail-way, now in progress. The rails used in the United States are of British man¬ ufacture. They are often taken to America as ballast; and the Government of the United States having remov¬ ed the duty from iron imported for the purpose of forming rail-ways, the rails are laid down on the quays of New York nearly at the same cost, as in any of the ports of Great Britain. Those of the Brooklyn and Jamaica road, which are in lengths of fifteen feet, and weigli thirty-nine pounds per lineal yard, are of British manufacture, and cost at New York, when they were landed, in 1836, £8 per ton; the cast-iron chairs, which are also of British manufacture, weigh about fifteen pounds each, and cost £9 per ton. There is a great abundance of iron ore in America, and some of the veins in the neighborhood of Pittsburg are at present pretty extensively worked ; but tlie Americans know that it would be bad economy to attempt to manufac¬ ture rails, so long as those made at Merthyr Tydvil Iron¬ works, in Wales, can be laid down at their sea-ports at the present small cost. The stone blocks, in use on some of tlie rail-ways, are macle ol granite, which is lound in many parts of the United States. Yellow nine is generally employed for tne longitudinal sleepers, and cedar, locust, or white-oaK, for the transverse sleepers on which the rails rest. Cedar, however, if it can be obtained, is generally preferred for the transverse sleepers, because it is not liable to be split by the heat of the sun, and is less affected than perhaps any other timber, by dampness and exposure to the at¬ mosphere. The cedar sleepers used on the Brooklyn and Jamaica rail-way, measuring six inches by five, and KAIL-WAYS IN THE UNITED STATES. 325 seven feet in length, notched, and in readiness to receive the rails, cost 2s. 3^d. each, laid down at Brooklyn. It is a costly timber, and is not very plentiful in the United States. It has also risen greatly in value, since the intro¬ duction of rail-ways, for the construction of which it is peculiarly applicable. For all treenails, locust-wood is universally employed. The American rail-roads are much more cheaply con¬ structed than those in England, which is owing chiefly to three causes; first, they are exempted from the heavy expenses often incurred in the construction of English rail¬ ways, by the purchase of land, and compensation for dam¬ ages ; second, the works are not executed in so substantial and costly a style ; and, third, wood, which is the prin¬ cipal material used in their construction, is got at a very small cost. The first six miles of the Baltimore and Ohio rail-road, which is formed “in an expensive man¬ ner, on a very difficult route,” has cost, on an average, about £12,000 per mile. The rail-roads in Pennsylva¬ nia cost about <£5000 per mile; the Albany and Sche¬ nectady rail-road, upwards of £6000 per mile ; the Sche¬ nectady and Saratoga rail-way, £1800 per mile ; and the Charleston and Augusta rail-road, about the same.* Mr. Moncure Robinson, in a report relative to the Philipsbuig and Juniata rail-road, states, that the first ten miles of the Danville and Pottsville rail-road, formed for a double track, but on which a single track only was laid, cost, on an average, £4400 per mile, and that the Honesdale and Carbondale rail-road, sixteen and one third miles in length, laid with a single track, and executed for a considerable Dortion of its length on truss-work, is understood, witn macninery, to nave averaged £3600 per miie. The average cost of these raii-ways, constructed in different parts of the United States, is £4942 per mile. This contrasts, strongly, with the cost of the rail-ways constructed in Great Britian. The Liverpool and Man¬ chester rail-way cost £30,000 per mile ; the Dublin and * Facts and suggestions relative to the New York and Albany rail¬ way, New York, 1833. II. 28 XII. 320 APPENDIX. Kingstown, £40,000 ; and the rail-way between Liverpool and London is expected to cost upwards of £25,000. The following extract, embodying an estimate from Mr. Robinson’s Report, will give some idea of the cheapness with which many of the American works are construc¬ ted :— “ The following plan,” says Mr. Robinson, “ is pro¬ posed for the superstructure of the Philipsburg and Juni¬ ata rail-road. “ Sills of white or post oak, seven feet ten inches long, and twelve inches in diameter, flattened to a width of nine inches, are to be laid across the road, at a distance of five feet apart, from centre to centre. In notches formed in these sills, rails of white-oak or heart-pine, five inches wide by nine inches in depth, are to be secured, four feet seven inches apart, measured within the rails. On the inner edges of these rails, plates of rolled iron, two inches wide by half an inch thick, resting at their points of junction on plates of sheet iron, one twelfth of an inch thick and four and a half inches long, are to be spiked, with five-inch wrought-iron spikes. The inner edges of the wooden rails to be trimmed slightly level¬ ling, but flush at the point of contact with the iron rail, and to be adzed down, outside the iron, to pass off rain¬ water. “ Such a superstructure, as that above described, would be entirely adequate to the use of locomotive engines of from fifteen to twenty horses’power, constructed without surplus weight, or similar to those now in use on the little Schuylkill rail-road in this State, (Pennsylvania,) or tne Petersburg rail-road in Virginia : and it will be observed mat only the sills, which constitute but a very slight item in its cost, are much exposed to the action of those causes which induce decay in timber. It is particularly recom¬ mended for the Philipsburg and Juniata rail-road, by the great abundance of good materials, along the line of the improvement, for its construction, and the consequent economy with which it may be made. “ The following may be deemed an average estimate of the cost of a mile of superstructure, as above described. RAIL-WAYS IN THE UNITED STATES. 327 1056 trenches, 8 feet long, 12 inches wide, and 14 inches Dolls. deep, filled with broken stone, at 25 cents each, • 264 Same number of sills, hewn, notched, and imbedded, at 50 cents each, ....... 628 10,912 lineal feet of rails, (allowing 33J per cent, for waste,) at 4 cents per lineal foot, delivered, . . 436.48 2112 keys, at 2.^ cents each, ...... 62.80 10,560 lineal feet of plate rails, 2 inches by ^ inch, weight lb. per foot, 15^^!^ tons, delivered at 50 dollars (£10) per ton, ....... 785.60 1609 lbs. of 5-inch spikes, at 9 cents per pound, . . 135.81 Sheet iron under ends of rails, ..... 30.21 Placing and dressing wood, and spiking down iron rails, 280 Filling between sills with stone, or horse-path, . . 180 2692 dollars, or about £540. 2692.80 It was found rather difficult to obtain much satisfactory information regarding the expense of upholding the Amer¬ ican rail-ways. It is stated in a report made by the Di¬ rectors of the Boston and Worcester rail-road, that Mr. Fessenden, their engineer, estimates the annual expendi¬ ture for repairing the road, carriages, and engines, and pro¬ viding fuel and necessary attendance for forty-three and a half miles of rail-way, at £6329 per annum, which is at the rate of £157 per mile. The expense of the repairs on the Utica and Schenectady rail-road, which is about seventy- seven miles in length, amounts to £28,000 per annum, be¬ ing at the rate of about £363 per mile. These sums for keeping rail-roads in repair are exceedingly small, compar¬ ed with the amount expended in this country for the same purpose. On the Liverpool and Manchester rail-way, for example, the expense annually incurred, in keeping the engines in a working state, and the rail-way in repair, amounts to upwards of £30,000. or £1000 per mile This difference in the cost arises, m a great measure. Iron; me comparatively slow speed at which the engines work¬ ing on the American rail-ways are propelled, which, in the course of my own observation, never exceeded the aver¬ age rate of fifteen miles per hour. On the State rail-ways, and also on many of those under the management of in¬ corporated companies, fifteen miles an hour is the rate of travelling fixed by the administration of the rail-way, and this speed is seldom exceeded. 32S APPENDIX. On some of the American rail-ways, where the line is short, or the traffic small, horse power is employed ; but locomotive engines for transporting goods and passen¬ gers, are in much more general use. In New York, Brooklyn, Philadelphia, Baltimore, and other places, which have lines of rail-way leading from them, the depot, or station for the locomotive engines, is generally placed at the outskirts, but the rails are continued through the streets, to the heart of the town, and the carriages are dragged over this part of the line by horses, to avoid the inconvenience and danger, attending the passage of loco¬ motive engines, through crowded thoroughfares. The fuel used on most of the rail-ways is wood, but the sparks vomited out by the,chimney are a source of constant annoyance to the passengers, and occasionally set fire to the wooden bridges on the line, and the houses in the neighborhood. Anthracite coal, as formerly no¬ ticed, has been tried, but the same difficulties which at¬ tend its use in steam-boat furnaces, are experienced, to an equal extent, in locomotiye engines. In situations where the summit-level of a rail-way can¬ not he attained, by an ascent sufficiently gentle for the employment of locomotive engines, or where the forma¬ tion of such inclinations, though perfectly practicable, would be attended with an unreasonably large outlay, transit is generally effected by means of inclined planes, worked by stationary engines. This system has been introduced on the Portage rail-way, over the Alleghany Mountains, in America, on a more extensive scale, than -in any other part of the world. The Portage or Alle¬ ghany rail-way lorms one of the links of the great Penn¬ sylvania canal and rail-road communication, from Phila¬ delphia to Pittsburg,—a work ot so difficult and vast a nature, and so peculiar, both as regards its situation and details, that it cannot fail to be interesting to every engi¬ neer, and I shall, therefore, state at some length the facts which I have been able to collect regarding it. This communication consists of four great divisions, the Columbia rail-road, the Eastern Division of the Penn¬ sylvania canal, the Portage or Alleghany railroad, and RAIL-WAYS IN THE UNITED STATES. 329 the Western Division of the Pennsylvania canal. These works form a continuous line of communication from Phil¬ adelphia, on the Schuylkill, to Pittsburg, on the Ohio, a distance of no less than three hundred and ninety-five miles. Commencing at Philadelphia, the first Division of this stupendous work is the Philadelphia and Columbia rail¬ road, which was opened in the year 1834. It is eighty- two miles in length, and was executed at a cost of about <£066,025, being at the rate of £8122 per mile. There are several viaducts of considerable extent on this rail-way, and two inclined planes worked by stationary engines. One of these inclined planes is at the Philadelphia end of the line. It rises at the rate of one in 14.6 for two thousand seven hundred and fourteen feet, overcoming an elevation of one hundred and eighty-five feet. The other plane, which is at Columbia, rises at the rate of one in 21.2 for a distance of one thousand nine hundred and fourteen feet, and overcomes an elevation of ninety feet. A very large sum is expended in upholding the inclined planes, and surveys have lately been made with a view to avoid them. The cost of maintaining the stationary power, and superintendence of the Philadelphia inclined plane, is said to be about £8000 per annum, and that of the Columbia plane, about £3498 per annum. Locomo¬ tive engines are used between the tops of the inclined planes. The steepest gradient on that part of the line is at the rate of one in one hundred and seventeen ; but the curves are numerous, and many of them very sharp, the minimum radius being so small as three hundred and fifty feet. This lino of rail-way was surveyed and laid out, before the application of locomotive power to rail-way conveyance had attained its present advanced state,—at a period when sharp curves and steep gradients were not considered so detrimental to the success of rail-ways, as experience has since shown them to be. The passenger-carriages on the Columbia rail-road are extremely large and commodious. They are seated for sixty passengers, and are made so high in the roof, that the tallest person may stand upright in them, without in¬ convenience. There is a passage between the seats ex- 28* 330 APPENDIX. tending from end to end, with a door at both extremities ; and the coupling of the carriages is so arranged, that the passengers may walk from end to end of a whole train, without obstruction. In winter, they are heated by stoves. The body of each of these carriages measures from fifty to sixty feet in length, and is supported on two four-wheeled trucks, furnished with friction-rollers, and moving on a vertical pivot, in the manner formerly alluded to, in describing the construction of the locomotive en¬ gines. The flooring of the carriages is laid on longitudinal beams of wood, strengthened with suspension-rods of iron. At the termination of the rail-way at Columbia, is the commencement of the Eastern Division of the Pennsyl¬ vania canal, which extends to Hollidaysburg, a town sit¬ uate at the foot of the Alleghany Mountains. This canal is rather more than one hundred and seventy-two miles in length, and was executed at an expense of £91*8,829, being at the rate of £5342 per mile. There are thirty-three aqueducts, and one hundred and eleven locks, on the line, and the whole height of lockage is 585.8 feet. A considerable part of this canal is slack- water-navigation, formed by damming the streams of the .Juniata and Susquehanna. The canal crosses the Sus¬ quehanna at its junction with the Juniata, at which point it attains a considerable breadth. A darn has been erec¬ ted in the Susquehanna, at this place, and the boats are dragged across the river by horses, which walk on a tow- path attached to the outside of a wooden bridge, at a lev¬ el of about thirty feet above the surface of the water. Hollidaysburg is the western termination of the East¬ ern Division of the Pennsylvania canal. The town stands at the base of the Alleghany Mountains, which ex¬ tend in a southwesterly direction, from New Brunswick, to the State of Alabama, a distance of upwards of eleven hundred miles, presenting a formidable barrier to commu¬ nication between the eastern and western parts of the United States. The breadth of the Alleghany range va¬ ries from a hundred to a hundred and fifty miles, but the peaks of the mountains do not attain a greater height than four thousand feet above the medium level of the sea. RAIL-WAYS IN THE UNITED STATES. 331 They rise with a gentle slope, and are thickly wooded to their summits. “ The Alleghany Mountains present what must be considered their scarp, or steepest side, to the east, where granite, gneiss, and other primitive rocks, are seen. Upon these repose, first, a thin forma¬ tion of transition rocks dipping to the westward, and next, a series of secondary rocks, including a very extensive coal formation.”* The National road, which has al¬ ready been noticed, was the first line of communication formed by the Americans over this range ; and in the year 1831, an Act was passed for connecting the Eastern and Western Divisions of the Pennsylvania canal, by means of a rail-road. This important and arduous work, which cost about £526,871, was commenced within the same year in which the Act for its construction was grant¬ ed, and the first train passed over it on the 26th of Novem¬ ber, 1833 ; but it was not till 1835, that both the tracks were completed, and the rail-way came into full operation. The rail-way crosses the mountains by a pass called “ Blair’s Gap,” where it attains its summit-level, which is elevated two thousand three hundred and twenty-six feet above the mean level of the Atlantic ocean. Mr. Robin¬ son surveyed a line of rail-way from Philipsburg to the river Juniata, which is intended to cross the Alleghany Mountains by the pass called “ Emigh’s Gap.” The summit-level of this line is stated, in a report by the di¬ rectors, to be two hundred and ninety-two feet lower than that of the Portage rail-way. The preliminary operation of clearing a track for the passage of the rail-way, from a hundred to a hundred and fifty feet in breadth, through the thick pine forests with which the mountains are clad, was one in which no small difficulties were encountered. This operation, which is called grubbing., is little known in the practice of engi¬ neering in this country, and is estimated by the Ameri¬ can engineers, in their various rail-way and canal reports, at from £40 to £80 per mile, according to the size and quantity of the timber to be removed ; an estimate which, from the appearance of American forests, must, in many ♦ Encyclopajdia Britannica, article .America. 332 APPENDIX. instances, be much too low. The timber removed from the line of the Alleghany rail-way is chiefly spruce and hemlock pine, of very large growth. The line is laid with a double track, or four single lines of rails, and is twenty-five feet in breadth. For a con¬ siderable distance, the rail-way is formed by side-cutting along steep sloping ground, composed of clay-slate, bitu¬ minous coal, and clay, part of the breadth of the road be¬ ing obtained by cutting into the hill, and part by raising embankments, protected by retaining walls of masonry. The rail-way is consequently liable to be deluged, or even entirely swept away, by mountain torrents, and the thor¬ ough drainage of its surface has been attended with great expense and difficulty. The retaining walls, by which the embankments are supported, are in some places not less than a hundred feet in height; they are built of dry- stone masonry, and have a batter of about one half to one, or six inches horizontal to twelve inches perpendic¬ ular. There are no parapet or fence walls on the rail¬ way, and on many parts of the line, especially at the tops of several of the inclined planes, the trains pass within three feet of precipitous rocky faces, several hundred feet high, from which the large trees, growing in the ra¬ vines below, almost resemble brushwood. One hundred and fifty-three drains and culverts, and four viaducts, have been built on the rail-way. One of the viaducts crosses the river Conemaugh, at an elevation of seventy feet above the surface of the water. There is also a tunnel on the line nine hundred feet in length, twenty feet in breadth, and nineteen feet in height. The inclined planes are, however, the most remarka¬ ble works which occur on this line. The rail-way extends from Hollidaysburg on the eastern base, to Johnstown on the western base, of the Alleghany Mountains, a distance of thirty-six miles ; and the total rise and fall, on the whole length of the line, is 2571.19 feet. Of this height, 2007.02 feet are overcome by means of ten inclined planes, and 564.17 feet by the slight inclinations given to the parts of the railway which extend between these planes. The distance from Hollidaysburg to the summit-level is about RAIL-WAYS IN THE UNITED STATES. 333 ten miles, and the height is 1398.31 feet. The distance from Johnstown to the same point is about twenty-six miles, and the height 1172.88 feet. The height of the summit-level of the rail-way, above the mean level of the Atlantic, is 2326 feet. The machinery by which the inclined planes are work¬ ed consists of an endless rope passing round horizontal, grooved wheels, placed at the head and foot of the planes, which are furnished with a powerful break, for retarding the descent of the‘trains. The ropes were originally made seven and a half inches in circumference, but they have lately been increased to eight inches, to prevent a tendency, which they formerly had, to slip in the grooved wheels, occasioned by their circumference being too small for the size of the groove, or hollow in the wheel. Two stationary engines, of twenty-five horses’ power each, are placed at the head of tlie inclined planes, one of which is in constant use in giving motion to the horizontal wheels round which the rope moves, while the trains are passing the inclined planes. Two engines have been placed at each station, that the traffic of the rail-way may not be stopped, should any accident occur to the machinery of that which is in operation ; and they are used alternately, for a week at a time. Water for supplying the boilers has been conveyed, at a great expense, to many of the sta¬ tions, in wooden pipes upwards of a mile in length. The planes are laid with a double track of rails, and an ascending and a descending train are always attached to the rope at the same time. Many experiments have been made, to procure an efficient safety-car, to prevent the trains from running to the foot of the inclined plane, in the event of the fixtures, by which they are attached to to the endless rope, giving way. Several of these safety- cars are in use, and are found to be a great security. The trains are attached to the endless rope simply by two ropes of smaller size made fast to the couplings of the first and last wagons of the train, and to the endless rope by a liitch or knot, formed so as to prevent it from slipping. Locomotive engines are used on the parts of the road between the inclined planes.— Stevenson^s ‘ Sketch of Civil Engineering in Jforth America.'* 334 APPENDIX Table of the Principal Rail-ways in operation in the United States, in 1840, NAME. COURSE. When Length Whole length opened Miles. in each Slate. Maine. Bangor and Orono, . From Bangor to Orono, 1836 10 10 New Hampshiue. Nashua and Lowell, Nashua to Lowell, Massachusetts. 1838 15 15 Quincy, C Quincy Quarries to Nepon- ( set River, . 11827 4 Boston and Lowell, . Boston to Lowell, . 1835 26 Andover and Wilmington, f Andover to the Boston and 1 Lowell Rail-road, 1 1836 7i Andover and Haverhill, Andover to Haverhill, . 1838 10 Boston and Providence, Boston to Providence, 1835 41 Dedham Branch, . f Boston and Providence R. ( Road to Dedham, 1 1835 2 Taunton Branch, ( Boston and Providence J Rail-road to Taunton, 1 1836 11 Boston and Worcester, Boston to Worcester, . 1835 45 Western Rail-way, . Worcester to Springfield, 1839 54 Worcester and Norwich, Worcester to Norwich, 1839 59 Eastern Rail-road, Boston to Newburyport, Rhode Island. 1839 36 295i Providence & Stonington, Providence to Stonington, Connecticut. 1837 47 47 Hartford and New Haven, Hartford to New Haven, 1839 40 Hoiisatonic, Bridgeport to New Milford, New York. • • 40 80 Mohawk and Hudson, f Between the Rivers Mo- j hawk and Hudson, . 1 1832 16 Saratoga & Schenectady, Saratoga to Schenectady, 1852 22 Rochester, . Rochester to Carthage, 1833 3 Ithaca and Oswego, Ithaca to Oswego, . 1834 29 Rensselaer and Saratoga, Troy to Ballston, 1835 244 Utica and Schenectady, Utica to Schenectady, . 1836 77 Buffalo and Niagara, . Buffalo to Niagara Falls, 1837 21 Ilaerlem, New York to Ilaerlem, 1837 7 Lockport and Niagara, Lockport to Niagara Falls, 1837 24 Brpoklyn and Jamaica, Brooklyn to Jamaica, 1837 12 Auburn and Syracuse, Auburn to Syracuse, Catskill to Canajoharie, , , 26 Catskill and Canajoharie, . • 68 Hudson and Berkshire, f Hudson to the Boundary of { Massachusetts, 30 Tonawanda, Rochester to Attica, New Jersey. 45 404i Camden and Amboy, . Camden to Amboy, 1832 61 Paterson, . Paterson to Jersey, 1834 16i New Jersey, . f Jersey City to New Bruns- ( wick. ^ 1836 31 Morris and Essex, Morristown to Newark, Pennsylvania. 20 128^ Columbia, . Philadelphia to Columbia, 82 Alleghany, f Hollidaysburg to Johns- J town, over the Alleghanies, }• ■ 36 Mauch Chunk, . C Mauch Chunk to the Coal- ^ mines, .... 1 1828 5 Room Run, . Mauch Chunk to the mines, • • 5i Carried forward. 128J 9804 RAIL-WAYS IN THE UNITED STATES 335 NAME. COURSE. When Length Whole length opened Miles. in each State. Brought forward. . • 128i 9301 Pennsylvania, continued. Mount Carbon, . MountCarbon to the mines. 1830 Schuylkill Valley,. ( Port Carbon to Tuscarora, ( with numerous branches. 30 Schuylkill, . • • • . . 13 Mill Creek, . Port Carbon to Mill Creek, 7 Minchill and Schuylkill, .*•••. 20 I’ine-grove, Pine-grove to Coal-mines, 4 Little Schuylkill, . Port Clinton to Tamaqiia, isa’i 23 Lackawaxen,. . C Lackawaxen Canal to the J River Lackawaxen, I- 16i Westchester, f Westchester to Columbia i Rail-road, . i 1832 9 Philadelphia and Trenton, Philadelphia to Trenton, 1833 26i Philadel phia& N orristown Philadelphia to Norristown 1837 19 Central Rail-way, Pottsville to Danville, 51i Philadelphia and Reading, Philadelphia to Reading, 40i Philadelphia & Baltimore, Philadelphia to Baltimore, • • 93 489 Delaware. Newcastle & Frenchtown, Newcastle to Frenchtown, 1832 16 16 Maryland. Baltimore and Ohio, f Completed to Harper’s ( Ferry, with branches. 1 1835 86 Winchester, f Harper’s Ferry to Wiii- j Chester, i 5- • 30 Baltimore & Port-Deposit, Ballimore to Port-Deposit, 341 Baltimore & Washington, Baltimore to Washington, i835 40 Baltimore & Susquehanna, Baltimore to York, . Virginia. 1837 59J 2491 Chesterfield, f Richmond to Chesterfield 13 \ Coal-mines, . 1- • Petersburg and Roanoke, ( Petersburg to Blakely, on t the Roanoke, }■ ■ 59 Winchester and Potomac, ( Winchester to Harper’s 1 Ferrv, . . S-- 30 Portsmouth and Roanoke, Portsmouth to Weldon, 77i Richmond, Fredericks- ? (Richmond to Fredericks- 1 58 burg, and Potomac, 5 1 burg, .... r • Manchester, Richmond to Coal-mines, 13 250J South Carolina. South Carolina Rail-road, f Charleston to Hamburg on J the Savannah, Georgia. 1 1833 136 136 Alatamaha & Brunswick, Alatamaha to Brunswick, • • 12 12 Alabama. Tuscumbia and Decatur, (Mussel-Shoals, Tennessee 1 46 t River, r • 46 Louisiana. Pontchartrain, ( New Orleans to Lake Pont- i chartrain. 1 1831 5 Carrollton, NewOrleans to Carrollton, Kentucky. • • 6 11 I^xington and Ohio, Lexington to Frankfort, 29 1 Frankfort and Louisville, Frankfort to Louisville, 50 79 Total length in miles. 2270 330 APPENDIX List of the other Rail-ways now in progress in the United States. Length NAME. COURSE. in Miles. New Hampshire. Haverhill and Exeter, Haverhill to Exeter, .... 18 Newburyport and Ports- > mouth, ... 3 Newburyport to Portsmouth, . 24 Massachusetts. Old Colony, Taunton to New Bedford, 20 Western, , . . Springfield to New York line, . 63 Connecticut. Western, . Hartford to Springfield, 27 New York. Long Island, Jamaica to Greenport, 50 New York and Erie, New York to Lake Erie, 505 Saratoga and Washington, Saratoga to Whitehall, 41 New Jbrsbv. Elizabethtown&Belvidere Elizabethtown to Beividere, 60 Burlington <&Mount Holly, Burlington to Mount Holly,' . 7 Pennsylvania. Oxford, Tioga, .... Columbia Rail-road to Port Deposit, 38 Chemung Canal to Tioga Coal-mines, 40 Virginia. Greensville and Roanoke, . 18 ■ South Carolina. 1 Charleston and Cincinnati, Charleston to Cincinnati, . 500 Georgia. Augusta and Athens, , Augusta to Athens, .... 100 Macon and Forsyth, Macon to Forsyth,. 25 Central Rail-road, Savannah to Macon, .... 200 Alabama. Montgomery and Chat- \ tahoochee, . . . 3 ■ ' * • • 90 Mississippi. Mississippi Rail-road. . Natchez to Canton, .... 150 Bowling Green and Bar-1 ren River, . . 3 Kentucky. Bowling Green to Barren River, . n Ohio. Mud River and Lake Erie, Dayton to Sandusky, .... 153 Sandusky & Monroeville, Sandusky to Monroeville, 16 Michigan. Detroit and St. Joseph, Detroit to the River St. Joseph, 200 Total length. 23463 MANUFACTURE OF MAPLE SUGAR. 337 VI.— Manufacture of Maple Sugar. The following account of the manufacture of sugar, from the sap of the maple tree, is copied from the North American Sylva of ftlichaux. The work is commonly taken in hand in the month of February, or in the beginning of March, while the cold continues intense, and the ground is still covered with snow. The sap begins to be in motion at this season, two months before the general revival of vegetation. In a central situation, lying convenient to the trees, from wdiich the sap is drawn, a shed is constructed, called a sugar-camp, which is destined to slielter the boilers, and the persons who attend them, from the weather. An auger,three quarters of an inch in diameter, small troughs to receive the sap, tubes of elder or sumac, eight or ten inches long, corresponding in size to the auger, and laid open for a part of their length, buckets for emptying the troughs and conveying the sap to the camp, boilers of fifteen or eighteen gallons capacity, moulds to receive the sirup w’hen reduced to a proper consistency for being formed into cakes, and, lastly, axes to cut and split the fuel, are the principal utensils employed in the operation. 'I’lie trees are perforated in an obliquely ascending di¬ rection, eighteen or tw'enty inches from the ground, with two holes, four or five inches apart. Care should be tak¬ en that the augers do not enter more than half an inch within the wmod, as experience has shown the most abun¬ dant flow of sap to take place at this depth. It is also recommended to insert the tubes on the south side of the tree ; but this useful hint is not always attended to. The troughs, which contain two or three gallons, are made in the Northern States, of white pine, of white or black oak, or of maple ; on the Ohio, the mulberry, which is very abundant, is preferred. The chestnut, the black walnut, and the butternut should be rejected, as they impart to the liquid the coloring matter and bitter principle, with which they are impregnated. A trough is placed on the ground, at the foot of each tree, and the sap is, every day, collected and temporarily II. 20 ' xn. 33S APPENDIX. poured into caski, from which it is drawn out to fill the boilers. The evaporation is kept up by a brisk fire, and the scum is carefully taken off during this part of the pro¬ cess. Fresh sap is added, from time to time, and the heat is maintained, till the licpiid is reduced to a sirup, after which it is left to cool, and then strained through a blanket, or other woollen stuff, to separate the remaining impurities. Some persons recommend leaving the sirup, twelve hours, before boiling it for the last time ; others proceed with it immediately. In either case, the boilers are only half filled, and by an active, steady heat, the liquor is rapidly reduced to the proper consistency for being poured into the moulds. The evaporation is known to have pro¬ ceeded far enough, when, upon rubbing a drop of the sirup between the fingers, it is perceived to he granular. If it is in danger of boiling over, a bit of lard or of but¬ ter is thrown into it, which instantly calms the ebullition. The molasses being drained off from the moulds, the .sugar is no longer deliquescent, like the raw sugar of the West Indies. Maple sugar, manufactured in this way, is lighter colored, in proportion to the care with which it is made, and the judgement with which the evaporation is conducted. It is superior to the brown sugar of the Colonies, at least, to such as is generally used in the United States ; its taste is as pleasant, and it is as good for culinary purposes. When refined, it equals in beauty the finest sugar consumed in Europe. The sap continues to flow for six weeks ; after which, it becomes less abundant, less rich in saccharine matter, and sometimes even incapable of crystallization. In this case, it is consumed in the state of molasses, which is superior to that of the West India Islands. After three or four days exposure to the sun, maple sap is converted into vinegar, by the acetous fermentation. The amount of sugar manufactured in a year varies, from difierent causes. A cold and dry winter renders the trees more productive than a changeable and humid season. It is observed, that when a frosty night is follow¬ ed by a dry and brilliant day, the sap flows abundantly ; MANUFACTURE OF BEET SUGAR. s.yj and two or three gallons are sometinjes yielded by a single tree, in twenty-four hours. Three persons are found sufficient to tend two hundred and fifty trees, which give one thousand pounds of sugar, or four pounds from each tree. But this product is not uniform, for many farmers on the Ohio do not commonly obtain more than two pounds from a tree. Trees, which grow in low and moist places, aflbrd a greater quantity of sap, than those, which occupy rising grounds, but it is less rich in the saccharine principle. That of insulated trees, left standing in the middle of fields, or by tbe side of fences, is the best. It is also re¬ marked, that in districts which have been cleared of other trees, and even of the less vigorous sugar maples, the pro¬ duct of the remainder is proportionally more considerable. VIE.— Of the Manufacture of Beet Sugar. The following account of this manufacture, in France, is extracted from a work compiled, in 1836, by Mr. Ed¬ ward Church. Cleansing of the Beet Roots. The object of this operation is, to separate from the roots the green parts of the neck, which may not have been removed, the radicles, the defective parts, and the earth and the gravel which may adhere to these ; wheo this is properly done, the washing, should it be required, (which is not the case in many places,) is easily and quickly performed. In all cases, the cleansing should be effectually done, otherwise the gravel and earth (should there any remain) will injure the rasps. Women and children perform this operation in France. For this pur¬ pose, each hand is provided with a sharp knife, from two to three inches broad, and ten long. With this tool, seated near a pile of beets, the laborer takes the beets one after another, scrapes tbem lengthwise, to detach the earth and stones, takes off the neck all round, and even a thin slice, when this has not been already done. AVhen a beet is too large to be applied conveniently to the rasp, the workmen should cut it in two, or in quarters, 340 APPENDIX. according to its dimensions. This must always be done longitudinally. The cleaning of the beets should always take place in a room near the rasps and presses, in order that these dif¬ ferent operations may follow conveniently and quickly. The place should be, when possible, a building sufficient¬ ly large to contain beets enough for the consumption of the works for at least four or five days, and leave room enough besides for the laborers to do their work easily. As fast as the roots are cleansed, they should be thrown into baskets about eighteen inches high, and a foot wide, of a conical shape, with handles. W hen several of these are filled they are carried to the rasp ; there they leave the full baskets and take back the empty ones. Two women, in France, who understand their business, can clean easily from three to three and one half tons of roots in twelve hours’ work, and carry them to the rasp. The wages of these women, in some parts of France, do not exceed twelve or fifteen cents each, per day ; at this rate, the cleaning of a ton of beets would not cost over ten cents. It, of course, reduces the weight of the beet ; the loss is estimated, usually,at from six to seven per cent. The operation of w'ashing the roots is, (as we before said,) by no means generally requisite ; and a careful cleansing, as described above, is decidedly preferable, and it is not always, that water in sufficient quantity can be con¬ veniently obtained. When a little stream is at hand, and they can be placed in baskets in the w ater, and remain till the earth is washed off by its motion, such a peculiar ad¬ vantage should never be neglected ; but this of rare occur¬ rence. This washing is the more difficult, too, as it must be executed in the winter, and the water frequently may be frozen. A general opinion once prevailed, that the cleans¬ ing with water was indispensable, and that the manufacture of sugar could not be undertaken without a locality which supplied an abundance of it ; but this supposed necessity is groundless, for there are few spots where a sufficiency of water may not be found for the inconsiderable wants of a beet sugar manufactory. MANUFACTURE OF BEET SUGAR. 341 Rasping the Beets. The first idea of the famous Achard, when in search of the best mode of extracting the sugar from beets, was to boil them and reduce them to paste ; but he soon found insuperable difficulties in the way of this process. The simple pressure without rasping has been repeatedly tried, and recently again by an improved press, and the rasp is as yet the only eftectual mode employed, and too much care cannot be used in having this operation well done, as on it depends, in a great measure, the more or less sugar that is obtained. There is a great diversity in the con¬ struction of this machine, but the cylindrical rasp of Mo- lard appears to have the preference. The cylinder is of cast-iron, into which One hundred and twenty saw plates are inserted. As a description of this would probably be unintelligible without a representation of it by an engrav¬ ing, I will not attempt it. A man presses the beets en¬ closed in a box against the circumference of the cylinder, another workman, on the opposite side of the machine, re¬ moves the pulp, and, with the ladle with which he removes it, fills bags, as w e shall more particularly explain hereaf¬ ter. From eighty to one hundred pounds of beet are re¬ duced to pulp, in one minute. The rasping requires, as well as every other operation of this manufacture, great activity ; and, as much as possi¬ ble, the rasping more beets than are immediately wanted, must be avoided, as a prejudicial change takes place in the pulp, from a quarter to a half hour, at most, after it is produced. A blackish color, which gradually increases, is the indication of this change. It is therefore prudent that no more should be rasped than can be immediately pressed. The rasp must be kept perfectly clean by repeated wash¬ ings. Once a day, at least, every part of the machine, and all the tools appertaining to it, should be carefully cleansed, because every portion of juice, or pulp, which is suffered to remain on them, would soon serve as a leaven to excite fermentation. It is immaterial what power is used to drive the rasps; 29 # 342 APPENDIX. animal, water, and steam, power, and even wind, is some* times used in France. Exlraction of the Beet Juice. A variety of machines, and of power, has been used, for the pressing of the pulp, as well as for rasping the roots. Of late the Hydraulic press has superseded almost every other, for this last operation, at least, in large man¬ ufactories. The pulp, enclosed in bags, is submitted to the action of this machine ; the bags are usually made of Russia duck. The cloth, though required to be strong, must not be so close that the juice cannot easily pass through it, or they will otherwise burst ; on the other hand, it must be sufficiently so, to prevent the pulp passing through the tissue. This last defect, however, is less to be feared than the first, so that the caution, most to be attended to, is, to avoid too close a texture ; and it must be recollected that it will become closer when saturated with the juice. The size of the bags may be varied, but, generally speaking, half a yard wide and one yard long is a convenient di¬ mension ; they should not be more than three fourths filled. The bags must be kept perfectly clean, and they should be washed every day in boiling water, with a small addi¬ tion of the sub-carbonate of soda. Wicker-work frames, on which the bags are to be piled, must be provided ; they should be made strong, and proportioned to the size of the platform of the press, that is, of the same dimen¬ sions ; they serve to support the piles of bags in their vertical position, on the hand-wagon, with which they are removed from the rasp to the press, and are themselves kept in place, when on the press, by stanchions, fixed to the platform of the press at the lower end, the other sliding through a groove fixed to the frame-work. These wicker-frames and bags are placed alternately under the press, usually to the number of thirty of eadi. As re¬ gards these frames, the caution of the cleanliness is re¬ newed, and, in a word, must be applied to every branch of this manufactory. A Reservoir is next to be provided, to receive the MANUFACTURE OF BEET SUGAR. 343 juice from the press, to be subsequently conveyed to the defecating boiler ; it must be supplied with pipes of com¬ munication with the press, and a pump to convey the juice it contains to the defecating boiler ; it should be placed on a lower level than the press, and receive the juice by an inclined plane. It must be made substantial¬ ly of wood, and lined with copper, having a concavity in the centre, into which the bottom of the pump must be inserted, so as to empty it completely. The capacity must, of course, depend on the extent of the manufactory. Mode of operating xcilh the Press. When the bags and wicker-frames have been piled as before described, alternately, to the number of thirty or more of each, on the platform, and the stanchions placed, tile weight of the pulp alone causes a pretty plentiful flow of juice ; if the press used is a screw press, a workman takes hold of the lever, and turns it, then a second man assists, and then a third. When they have exerted their united strength on the lever, the job is done, and, after al¬ lowing the bags to drain, whilst they are filling others, the press is unscrewed, the bags removed, the pulp cakes disposed of, the bags cleansed, and the operation first de¬ scribed is continued, till the whole quantity of pulp pre¬ pared is disposed of. Defecation of the Juice. The juice of the beet, as it comes from the press, car¬ ries with it all the soluble parts of the root. It contains, in this state, not only sugar and water, but other compo¬ nent parts, wliich cannot be separated by evaporation alone ; they must be precipitated by chemical agents. Ma¬ ny and expensive experiments were made in search for these, which I shall not here attempt to explain. The present process is as follows ; Suppose a boiler contain¬ ing four hundred gallons of juice ; add, before lighting the fire, eight pounds sulphuric acid at sixty-six degrees, one part acid, three parts water, diluted, mix quickly and thoroughly with the juice, then take nine pounds of quick¬ lime, weighed before it is slaked, then slake with warm 344 APPENDIX. water to the consistency of milk, throw this also into the juice, and stir the whole completely; the fire is now to be kindled under the boiler, and its contents raised to the temperature of one hundred and ninety degrees of Fah¬ renheit ; then animal carbon, that has been employed in clarification, is added, and well mixed, and a portion of diluted ox blood stirred in carefully ; the fire is withdrawn, the juice allowed to settle, and is drawn off clear, through a cock placed near the bottom of the boiler. It is im¬ portant to observe that the juice, when the sulphuric acid is added, must not be warm. This process has failed in the hands of some imitators of M. Crespel, from a mis¬ take on this point. M. Dubrurifaut acknowledges that he himself committed it. Concetiiraiioii of Ike Juice. For this purpose, one or more boilers are necessary, with which the evaporation is begun and finished ; in these the juice from the defecating boiler is received clear ; then a slow fire is kept up in the beginning, and some al- buginous matter, (white of eggs, or blood,) added, if it should seem to be required. After this, a man must at¬ tend closely to the boiler, and manage the fire. When froth appears, it will be his duty to throw a small piece of but¬ ter, or other grease, (which he should have near him,) into the vessel, which will immediately cause it to subside ; he should also have a ladle to stir it when required. When th(j juice has reached the proper point, that is to say, twenty-six degrees of Baumes’s areometer, when boiling, that is thirty degrees, when cold, it is time to proceed to the operation of clarifying. Clarifying. The object of this is, to separate the sirup concen¬ trated to thirty degrees, or near it, from the extraneous matter which it holds in suspension, and moreover to de¬ prive it, by clarifying agents, of all coloring matter, and other foreign substances which were in the juice, or have formed there whilst under the preceding operation, all which matter is injurious to the sugar. Clarification mav MANUFACTURE OF BEET SUGAR. 345 be divided into two distinct branches, the one chemical, having for its object, by clarifying agents, such as animal carbon, albumine, &c., to purify the sirup ; the other, me¬ chanical, having for its object to separate from the same, the carbon and other solid bodies agglomerated by the al¬ bumine. The first is managed with a boiler, only because the action of the chemical agents employed require to be aided by heat. Of all the means hitherto devised for clarification, none has been found so simple and so effective as that offered by the use of animal carbon, and albuginous or caseous matter.* We will here suppose that the object in view is to clarify the portion of sirup, supplied by the defecation of one hundred gallons of juice, that is, sixteen and a half gallons of sirup concentrated to twenty-six degrees boil¬ ing and thirty degrees cold ; (it follows that for any other quantity it is only required to follow the same proportion ;) to do this, we must proceed to weigh eight pounds of ani¬ mal carbon, and throw it into the boiler ; the siruj), when boiling, should be well stirred with the ladle, then with the skimmer ; the black agglomerated matter which rises to the surface should be broken up, and mixed again with the liquid ; when it is apparent that the carbon is sufficiently separated and mixed with the sirup, it may be left to boil for a few minutes. The sirup now assumes a turbid and murky appearance ; whilst this operation is proceeding, a quart of ox blood, or the white of four eggs, should be beat up, and diluted with water, or otherwise, two quarti- of skimmed milk. This mixture must now be thrown into the boiler, taking care to mix the whole, well together. The ebullition will, of course, have been stopped by this addition ; and it is proper, till it begins again to boil, that it should be constantly stirred, to prevent the precipitation of the ingredients ; the ebullition must be kept up for a few minutes, and the sirup is then prepared for filtration. * The process vve are about to describe is varied by different man¬ ufacturers. By some, the acid is omitted altogether, and other agents substituted. APPENDIX. JU6 Filtration. This is an exceedingly simple operation ; a flannel cloth fixed to a frame is all that is required. Sirup at the density of thirty degrees cold, as it comes from the filterer, is not sufficiently concentrated to crystal¬ lize ; it is therefore necessary to submit it to another boil¬ ing, to evaporate the superabundant water it still contains, and so to produce the required crystallization. This operation is only a continuation of the concentra¬ ting process, and also its completion ; the same boiler, which is suitable for the first part of this process, is the one now again required, the fire must be carefully attend¬ ed to, the sirup skimmed when required, and, if it rises in foam, must be stopped, as before, by a piece of grease; when the proof shows ninety and one half to ninety-one of Reaumer, tw'o hundred and thirty-six degrees Fahren¬ heit, which point it may reach, if the sirup is very good, it is time to stop and empty the boiler. It would be more prudent to do so at eighty-nine and one half; the sugar would purify more easily, and, as the molasses must neces¬ sarily be reboiled, this supports the operation, all the bet¬ ter, for being a little richer in sugar. The sixteen and one half gallons, with which we began our experiment, will new be reduced to ten and one half gallons. In this state it may be turned into a vessel, to cool gradually, where it may stay for ten or twelve hours, w'hen it will fall to the temperature of one hundred and seventy degrees, or one hundred and eighty degrees, Fah¬ renheit, and then may be put into the pots for crystalliza¬ tion. These usually contain six to eight gallons. In turning it into these, masses of the crystals will be found, already, at the bottom and sides of the vessel. If the sirup is good, some attention is necessary in this operation, that the sirup should not be left to get too cold, before it is turned into the pots ; as this would, in some degree, impede the crys¬ tallization. These should be kept in a close room, and at a steady temperature. The pots are of a conical form, with a hole in the bottom, which is stopped with a cork or clay. Thirty-six or forty hours after the sirup has remained in. MANUFACTURE OF BEET SUGAR. S47 them, and when the temperature is reduced to seventy- seven degrees, Fahrenheit, or thereabout, the cork is re¬ moved, and the point of the cone placed over a vessel into which the molasses (which begins immediately to run) is received. In about fifteen days, in a temperature of from sixty to sixty-five degrees, Fahrenheit, they have furnished above two thirds of their molasses. In this degree of heat the whole of the molasses will not separate from the sugar ; the pots are therefore removed to another room, where the temperature is kept at from one hundred and twenty to one hundred and forty degrees, Fahrenheit. There they are again placed over the recipients ; but, before doing this, a rod is thrust through the hole in the point of the cone, to break the incrustation of sugar within, and facilitate the draining of the molasses. After remaining here fifteen days, the sugar must be completely freed from the molas¬ ses, and must now be taken out. For this purpose, the cone is placed on its base, shook against the platform on which it stands, and, in an hour or so, the sugar is de¬ tached in the form of the cone ; the point of this is im¬ pregnated with molasses, and is to be removed. It makes an inferior sort of brown sugar. The rest of the product will be generally fine, light colored sugar, which is found to produce a larger pro[)ortion of refined sugar to the weight, than any made from the cane, and is, therefore, much preferred by refiners. The sugar made at the be¬ ginning of the season is easier made, and better than that made later. The molasses collected in the process of crystallization, is reboiled, and subjected to the same process as the sir¬ up, and a certain portion of sugar is tlie result; the re¬ siduum is used for many purposes, and is especially use¬ ful for cattle. For further particulars, see the work cited ; also, a man¬ ual translated from portions of the treatise of M. M. Blachette, Zoega, and J. De Fontenelle, and published by Marsh, Capeu, Lyon, and Webb, and a more recent work, on the same subject, by David Lee Child. 343 APPENDIX. VIII.— Voltaic Electrical Engraving. The following account of the process of engraving in relief, upon copper-plates, by means of voltaic electricity, is from the London Atheneum, for October 27, 1839. A previous number of this paper contained a letter from M. Jacobi, detailing his experiments on the subject; and it appears that Mr. Thomas Spencer, of Liverpool, had also devoted much attention to the subject, and had not only succeeded in doing all that M. Jacobi had done, but had surmounted difficulties which M. Jacobi could not. Mr. Spencer proposes, by means of voltaic electricity, “ to engrave in relief upon a plate of copper ; deposit a voltaic copper-plate, having the lines in relief; obtain a facsimile of a medal, reverse or obverse, or of a bronze cast; to obtain voltaic impression from plaster, or clay , and to multiply the number of already-engraved copper¬ plates.” The results which he has already obtained are said to be very beautiful. Take a plate of copper, such as is used by an engrav¬ er ; solder a piece of copper wire to the back part of it, and then give it a coat of wax; (this is best done by heat¬ ing the plate, as well as the wax ;) then write or draw the design on the wax, with a black lead pencil, or a point. The wax must now be cut through with a graver, or steel point, taking special care that the copper is thoroughly exposed, in every line. The shape of the tool or graver employed must be such, that the lines made are not V- shape, but, as nearly as possible, with parallel sides. The plate should next be immersed in dilute nitric acid ; say three parts water to one of acid. It will at once be seen whether it is strong enough, by the green color of the so¬ lution, and the bubbles of nitrous gas evolved from the copper. Let the plate remain in it long enough for the exposed lines to get slightly corroded, so that any minute portions of wax, which might remain, may be removed. The plate, thus prepared, is placed in a trough, separat¬ ed into two divisions by a porous partition of plaster of Paris, or earthenware ; the one division being filled with a saturated solution of sulphate of copper, and the other VOLTAIC ELECTRICAL ENGRAVING. 349 with a saline, or acid, solution. The plate to be engrav¬ ed is placed in the division containing the solution of the sulphate of copper, and a plate of zinc, of equal size, is placed in the other division. A metallic connection is .hen made between the copper and zinc plates, by means of the copper wire soldered to the former ; and the vol¬ taic circle is thus completed. The apparatus is then left for some days. As the zinc dissolves, metallic copper is precipitated, from the solution of the sulphate on the copper-plate, wherever the wax has been removed by the engraving tool. After the voltaic copper has been deposited in the lines engraved in the wax, the surface of it will be found to be more or less rough, according to the quickness of the action. To remedy this, rub the surface with a piece of smooth flag, or pumice-stone, with water. Then heat the plate, and wash off the wax ground, with spirits of turpentine and a brush. The plate is now ready to be printed from, at an ordmary press. In this process, care must be taken that the surface of the copper in the lines be perfectly clean, as otherwise, the deposited copper wall not adhere with any force, but is easily detached wdien the wax is removed. It is in order to insure this perfect cleanness of the copper, that it is immersed in dilute nitric acid. Another cause of imperfect adhesion of the deposited copper, which Mr. Spencer has pointed out, is the presence of a minute portion of some other metal, such as lead, which, by be¬ ing precipitated before the copper, forms a thin film, wdiich prevents the adhesion of the subsequently deposit¬ ed copper. This circumstance may, however, be turn¬ ed to advantage, in some of the other applications of Mr. Spencer’s process, wliere it is desirable to prevent the adhesion of the deposited copper. In copying a coin, or medal, ^Ir. Spencer describes two methods. The one is by depositing voltaic copper on the surface of the medal, and thus forming a mould, from which,facsimiles of the original medal may readily be ob¬ tained, by precipitating copper into it. The other is even more expeditious. Two pieces of clean milled II. 30 XII. 350 APPENDIX. sheet lead are taken, and the medal being placed between them, the whole is subjected to pressure in a screw-press, and a complete mould, of both sides, is thus formed in the lead, showing the most delicate lines, (in reverse.) Twenty, or even a hundred, of these, may be so formed on a sheet of lead, and the copper deposited by the vol¬ taic process, with the greatest facility. Those portions of the surface of the lead, which are between the moulds, may be varnished, to prevent the deposition of the lead, or, a whole sheet of voltaic copper having been deposi¬ ted, the medals may afterwards be cut out. When cop¬ per is to be deposited on a copper mould, or medal, care must be taken to prevent the metal deposited adhering. This Mr. Spencer effects by heating the medal, and rubbing a small portion of wax over it. This wax is then wiped off, a sufficient portion always remaining to pre¬ vent adhesion. Enough has been said, to enable any one to repeat, and follow up, Mr. Spencer’s interesting experiments. The variations, modifications, and adaptations, of them, are endless ; and many new ones wdll naturally suggest themselves to every scientific reader. IX.— Photogenic Drawing. Some account of Photography, or Photogenic drawing has been introduced in the previous pages of this work- The following article, containing a description of the pro¬ cess, is from a work on this subject, published by M. Da¬ guerre, and translated by Mr. Memes, in 1839. The designs are executed upon thin plates of silver, plated on copper. Although the copper serves princi¬ pally to support the silver foil, the combination of the two metals tends to the perfection of the eflect. The silver must be the purest that can be procured. As to the cop¬ per, its thickness ought to be sufficient to maintain the perfect smoothness and flatness of the plate, so that the images may not be distorted by the warping of the tablet; but unnecessary thickness, beyond this, is to be avoided, on account of the weight. The thickness of the two metals united ought not to exceed that of a stout card. PHOTOGENIC DRAWING. 351 The process is divided into five operations. 1. The first consists in polishing and cleaning the plate, in order to prepare it for receiving the sensitive coating, upon which the light traces the design. 2. The second is to apply this coating. 3. The third is the placing the prepared plate, pr-oper- ly, in the camera obscura, to the action of light, for the purpose of receiving the image of Nature. 4. The fourth brings out this image, which, at first, is not visible, on the plate being withdrawn from the camera obscura. 5. The fifth, and last, operation has, for its object, to remove the sensitive coating on which the design is first impressed, because this coaling would continue to be af¬ fected by the rays of light, a property which would ne¬ cessarily and quickly destroy the picture. First Operation.—Preparing the Plate. The requisites,for this operation, are, A small phial containing olive oil. Some very finely-carded cotton. A small quantity of very fine pumice powder, ground with the utmost care, tied up in a bag of muslin, suffi¬ ciently thin to allow the powder to pass through, when the bag is shaken. A phial of nitric acid, diluted with water, in the pro¬ portion of one pint of acid, to sixteen pints of distilled water. These proportions express volume, not weight. A frame of iron wire, upon which to place the plate, in order that it may be heated by means of a spirit-lamp. Lastly, a small spirit-lamp. As already stated, these photographic delineations are executed upon silver, plated on copper. The size of the plate will depend, of course, on the dimensions of the camera. We must begin, by polishing it carefully. To accomplish this, the surface of the silver is powdered all over with tlie pumice, by shaking the bag, without touch- ’ng the plate. Next, witli some cotton dipped in a little olive oil, the operator rubs the plate gently, rounding his strokes. Dur- 352 APPENDIX. ing this operation, the plate must be laid flat upon several folds of paper, care being taken to renew these, from time to time, that the tablet be not twisted from any inequality in the support. The pumice must be renewed, and the cotton changed, several times. The mortar, employed for preparing the pumice, must be of porphyry. The powder is afterwards liihshed, by grinding upon polished glass with a glass rnuller, and very pure water. And lastly, it must be perfectly dried. It will be readily apprehended, of what importance it is to attend to these directions, since upon the high polish of the silver, depends, in a great measure, the beauty of the future design. When the plate is well polished, it must next be cleaned, by powdering it all over, once more, with pumice, and rubbing with dry cot¬ ton, always rounding and crossing the strokes, for it is impossible to obtain a true surface by any other motion of the hand. A little pledget of cotton is now rolled up, and moistened with the diluted acid already mentioned, by applying the cotton to the mouth of the phial, and in¬ verting it, pressing gently, so that the centre only of the cotton may be wetted, and but slightly, care being taken, not to allow any acid to touch the fingers. The surface of the plate is now rubbed equally, all over, with the acid, applied by the pledget of cotton. Change the cot¬ ton, and keep rubbing, rounding as before, that the acid may be equally spread, yet in so small a quantity, as just to skim the surface, so to speak. If, as v/requently hap¬ pens, the acid run into small drops, from the high polish, change the cotton repeatedly, and break down the glob¬ ules as quickly as possible, but always by gently rubbing, for if allowed to rest, or to run upon the plate, they will leave stains. It will be seen when the acid has been properly diffused, from the appearance of a thin veil, spread regularly over the whole surface of the plate. Once more powder over pumice, and clean it with fresh cotton, rubbing as before, but very slightly. The plate is now to be subjected to a strong heat. It is placed upon the wire frame, the silver upwards. The spirit-lamp is applied below the hand, moving it round. PHOTOGENIC DRAWING. 353 the flame touching and playing upon the copper. This operation being continued at least five minutes, a white strong coating is formed all over the surface of the silver, if the lamp has been made to traverse with proper regu¬ larity. The lamp is now withdrawn. A fire of charcoal may be used instead of the lamp, and is, perhaps, prefera¬ ble, the operation being sooner completed. In this latter case, the wire frame is unnecessary, because the plate may be held by one corner with pincers, and so held over the fire, moving it at the same time, till all is equally heat¬ ed, and the veil appear, as before described. The plate is now to be cooled, suddenly^ by placing it on a cold substance, such as a mass of metal, or stone, or, best of all, a marble table. When perfectly cold, it is to be again polished, an operation speedily performed, since the gummy appearance merely has to be removed, which is done by the dry pumice and cotton, repeated several times, changing the cotton frequently. The polishing being thus completed, the operation of the acid is to be repeated three different times, dry pumice being powder¬ ed over the plate, each time, and polished off very gen¬ tly with the cotton, which must be very clean, care being taken not to breathe upon the plate, or to touch it with the fingers, or even with the cotton upon which the fingers have rested ; for the slightest stain upon the surface will be a defect in the drawing. When the plate is not intended for immediate use, the last operation of the acid is not performed. This allows any number of plates to be kept prepared, up to the last slight operation ; and they may be purchased in this state, if required. It is, however, indispensable, that a last operation by acid, as described, be performed on every plate, immediately before it be placed in the camera. Lastly, every particle ^f dust is removed, by gently cleaning the whole edges, and back, also, with cotton. Second Operation.—Coating the Plate. For this operation, we require, A box. A small board. 30* 354 APPENDIX. Four small metallic bands, the same substance as the plates. A small handle, and a box of small tacks. A phial of iodine. The plate is first to be fixed on the board, by means of the metallic bands, with their small catches and tacks. The iodine is now put into a little dish at the bottom of the box. It is necessary to divide the iodine into pieces, in order to render the exhalation the more extensively and more equally diffused ; otherwise, it would form cir¬ cles in the centre of the plate, which would destroy this essential requisite. The board is now fitted into its po¬ sition, the plate face downwards, the whole being support¬ ed by small brackets projecting from the four corners of the box, the lid of which is then closed. In this posi¬ tion, the apparatus remains till the vaporization of the iodine, which is condensed upon the plate, has covered its surface with a fine coating of a yellow gold color. If this operation be protracted, the gold color passes into violet, which must be avoided ; because in this state the coating is not so sensitive to the impressions of light. On the contrary, if the coating be too pale, the image of Nature in the camera will be too faint to produce a good picture. A decided gold color,—nothing more, nothing less,—is the only assurance that the ground of the future picture is duly prepared. The time for this cannot be determined, because it depends on several circumstances. Of these, the two principal are the temperature of the apartment, and the state of the apparatus. The opera¬ tion should be left entirely to spontaneous ev'aporation of the iodine ; or, at all events, no other heat should be used, than what can be applied through the temperature of the room, in which the operation takes place. It is also very important, that the temperature qf, the inside of the box be equal to that of the air outside ; for, otherwise, a depo¬ sition of moisture takes place upon the plate, a circuin- • stance most injurious to the final result. Secondly, as respects the state of the apparatus ; the oftener it has been used, the less time is required, because, in this case, the interior of the box being penetrated with the vapors PHOTOGENIC DRAWING. 355 ♦ of iodine, these arise from all sides, condensing thus more equally and more rapidly upon the surface of the plate ; a very important advantage. Hence, it is of consequence to leave always a small quantity of iodine in the cup, and to protect this latter from damp. Hence, likewise, it is obvious, that an apparatus of this kind, which has been some time in use, is preferable to a new box ; for, in the former, the operation is alw'ays more expeditiously performed. Since, from these causes, the time cannot be fixed, a priori, and may vary from five minutes to half an hour, rarely more, unless the weather be too cold, means must be adopted for examining the plate, from time to time. In these examinations, it is important not to allow the light to fall directly upon the plate. Also, if it appear that the color is deeper on one side of the plate than the other, to equalize the coating, the board must be re¬ placed, not exactly in its former position, but turned one ^quarter round, at each inspection. In order to accom¬ plish these repeated examinations, without injuring the sensibility of the ground, or coating, the process must be conducted in a darkened apartment, into which the light is admitted sideways, never from the roof; the door left a little ajar answers best. When the operator would inspect the plate, he raises the lid of the box, and, lifting the board with both hands, turns up the plate quickly, and very little light suffices to show him the true color of the coating. If too pale, the plate must be instantly replaced, till it attain the proper gold tone ; but if (his tint be passed, the coating is useless, and the operations must be repeated from the commencement of the first. From description, this operation may, perhaps, seem difficult ; ^ut with a little practice, one comes to know, pretty nearly, the precise interval necessary to produce the true tone of color, and also to inspect the plate with great rapidity, so as not to allow time for the light to act. When the coating has reached the proper tone of yel¬ low, the plate, with the board to which it is fixed, is slip¬ ped into the frame, and thus adjusted, at once, in the ca¬ mera. In this transference, care must be taken to protect 356 APPENDIX. the plate from the light. A taper should be used ; and even with this precaution, the operation ought to be per¬ formed as quickly as possible, for a taper will leave traces of its action, if continued for any length of time. We pass now to the third operation, that of the ca mera. If possible, the one should immediately succeed the other ; the longest interval between the second and third ought not to exceed an hour. Beyond this space, the action of the iodine and silver no longer possesses the requisite photogenic properties. Observanda .—Before making use of the box, the oper¬ ator should clean it thoroughly, turning it bottom upwards, in order to empty it of all the particles of iodine which may have escaped from the cup, avoiding, at the same time, touching the iodine with the fingers. During the operation of coating, the cup ought to be covered with a piece of gauze stretched on a ring. The gauze regulates the evaporation of the iodine, and also prevents the com¬ pression of the air, on the lid being shut, from scattering the particles of iodine, some of which, reaching the plate, would leave large stains on the coating. For the same reason, the top should always be let down with the great¬ est gentleness, not to raise the dust in the inside, the par¬ ticles of w'hich, being charged with the vapor of the io¬ dine, would certainly reach and damage the plate. Third Operation .— The Camera. The apparatus, required in this operation, is limited to the camera obscura. This third operation is that, in which, by means of light, acting through the camera, Nature impresses an image of herself on the photographic plate, enlightened by the sun, for then the operation is more sf#edy. It is easy to conceive that this operation, being accom¬ plished only through the agency of light, will be the more rapid in proportion as the objects, whose photographic images are to be delineated, stand exposed to a strong illumination, or in their own nature present bright lines, and surfaces. After having placed the camera in front of the land PHOTOGENIC DRAWING. 357 scape, or facing any other object of which it may be desi¬ rable to obtain a representation, the first essential is a per¬ fect adjustment of the focus, that is to say, making your arrangements, so as to obtain the outlines of the subject with great neatness. This is accomplished, by advancing or withdrawing the frame of the obscured glass, which re¬ ceives the images of natural objects. The adjustment being made with satisfactory precision, the movable part of the camera is fixed by the proper means, and the ob¬ scured glass being withdrawn, its place is supplied by the apparatus, with the plate attached, as already described, and the wliole secured by small brass screws. The light is, of course, all this time excluded by the inner doors. These are'now opened, by means of two semicircles, and the plate is disposed, ready to receive its proper impres¬ sions. It remains only to open the aperture of the ca¬ mera, and to consult a watch. This latter is a task of some nicety, inasmuch as noth¬ ing is visible, and it is quite impossible to determine the time necessary for producing a design, this depending entirely on the intensity of the light on the objects, the imagery of which is to be reproduced. At Paris, for ex¬ ample, this varies from three to thirty minutes. it is likewise to be remarked, that the seasons, as well as the hour of the day, exert considerable influence on the celerity of the operation. Tlie most favorable time is from seven to three o’clock ; and a drawing which, in the months of June and July, at Paris, may be taken in three or four minutes, will require five or six, in May or August; seven or eight, in April and ??eptember; and so on, in proportion to the progress of the season. These are only general data for very bright, or strongly illumin¬ ated, objects ; for it often happens, that twenty minutes are necessary, in the most favorable months, when the objects are entirely in shadow. After what has just been said, it will readily occur to the reader, that it is impossible to specify, with precision, the exact length of time necessary to obtain photographic designs. Practice is the only sure guide ; and, with this advantage, one soon comes to appreciate the required 358 APPENDIX. time, very correctly. The latitude is, of course, a fixed element in this calculation. In the south of France, for example, and generally in all those countries, in which light has great intensity, as Spain, Italy, &.c., we can easily understand that tliese designs must be obtained with greater promptitude, than in more northern regions. It is, however, very important, not to exceed the time nec¬ essary, in different circumstances, for producing a design ; because, in that case, the lights in the drawing will not clear, but will be blackened by a too-prolonged solariza- tion. If, on the contrary, the time has been too short, the sketch will be very vague, and without the proper details. Supposing that he has failed hi a first trial, by with¬ drawing the tablet too soon, or by leaving it too long ex¬ posed, the operator, in either case, should commence with another plate immediately ; the second trial, being corrected by the first, almost insures success. It is even useful, in order to acquire experience, to make some es¬ says of this kind. In this stage of the process, it is the same as for the coating ; wejnust hasten to the next operation. When the plate is withdrawn from the camera, it should imme¬ diately be subjected to the subsequent process ; there ought, at most, not to be a longer interval than an hour, between the third and fourth operations ; but one is al¬ ways surest of disengaging the images, when no space has been allowed to intervene. Fourth Operation. — Mercurial, or Disengaging, Process. Here are required, a phial of mercury, containing at least three ounces. A lamp, with spirit of wine. An iron vessel, prepared with apparatus for receiving the plate, and submitting it to the vapor of mercury. A glass funnel with a long neck. By means of the funnel, the mercury is poured into the cup, at the bottom of the larger vessel. The quan¬ tity must be sufficient to cover the bulb of a thermome¬ ter. Afterwards, and throughout the remaining opera¬ tions, no light, save a taper, can be used. PHOTOGENIC DRAWING. The board, with the plate affixed, is now to be with¬ drawn from the frame already described, as adapted to the camera. The board and plate are placed within the ledges of the black iron vessel, at ah angle of forty-five degrees, the tablet with sketch downwards, so that it can be seen through the glass. The top is then gently put down, so as not to raise up particles of the mercury. When all things are thus disposed, the spirit lamp is lighted, and placed under the cup containing mercury. The operation of the lamp is allowed to continue till the thermometer, the bulb of which is covered by the mer¬ cury, indicates a temperature of sixty degrees centigrade, [140°, Fahrenheit.] The lamp is then immediately with¬ drawn. If the thermometer has risen rapidly, it will con¬ tinue to rise without the aid of the lamp ; but this elevation ought not to exceed seventy-five degrees centigrade, [167° Fahrenheit.] The impress of the image of Nature exists upon the plate, but it is invisible. It is not till after the lapse ot several minutes, that the faint tracery of objects begins to appear, of which the operator assures himself, by looking through the glass, by the light of a taper, using it cau¬ tiously, that its rays may not fall upon, and injure, the nas¬ cent images of the sketch. The operation is continued till the thermometer sink to forty-five degrees centigrade, [113°, Fahrenheit;] the plate is then withdrawn, and this operation completed. When the objects have been strongly illuminated, oi when the action in the camera has been continued rather too long, it happens that this fourth operation is completed before the thermometer has fallen even to fifty-five degrees centigrade. One may always know this, however, by ob¬ serving the sketch through the glass. It is necessary, after each operation, to clean the inside of the apparatus carefully, to remove the slight coating of mercury adhering to it. When the apparatus has to be packed, for the purpose of removal, the mercury is with¬ drawn by a small cock, inclining the vessel to that side. One may now examine the sketch, by a feeble light, in order to be certain that the processes hitherto have sue- 360 APPENDIX. ceeded. The plate is now detached from the board, and the little bands of metal, which held it there, are carefully cleaned with pumice and water, after each experiment; a precaution rendered necessary from the coating both of iodine and mercury, which they have acquired. The plate is now deposited in the grooved box, until it undergoes the fifth and last operation. This may be deferred, if not con¬ venient ; for the sketch may now be kept for months, in its present state, without alteration, provided it be not too frequently inspected by the full daylight. Fifth Operation.—Fixing the Impression. The object of this final process, is to remove from the tablet the coating of iodine, which, continuing to decom¬ pose by light, would otherwise speedily destroy the de¬ sign, when too long exposed. For this operation, the re¬ quisites are, A saturated solution of common salt, or a weak solu¬ tion of hyposulphite of pure soda. An apparatus of japanned white iron, for washing the designs. T wo square troughs, of sheet copper. A vessel for distilled water. In order to remove the coating of iodine, common salt is put into a bottle, with a wide mouth, which is filled one fourth with salt and three fourths with pure water. To dissolve the salt, shake the bottle, and, when the whole forms a saturated solution, filter through paper. This solution is prepared in large quantities, beforehand, and kept in corked bottles. Into one of the square troughs, pour the solution, filling it to the height of an inch ; into the other, pour, in like manner, your water. The solution of salt may be re¬ placed by one of hyposulphite of soda, which is even preferable, because it removes the iodine entirely, which the saline solution does not always accomplish, especially when the sketches have been laid aside for some time, be¬ tween the fourth and fifth operations. It does not require to be warmed, and a less quantity is required. First, the plate is placed in common water, poured into PHOTOGENIC DRAWING. 361 a trough, plunging and withdrawing it immediately, the surface merely requiring to be moistened ; then plunge it into the saline solution, which latter would act upon the drawing, if not previously hardened by the washing in pure water. To assist the effect of the saline solutions, the plate is moved about in them, by means of a little hoop of coppei wire. When the yellow color has quite disap¬ peared, the plate is lifted up with both hands, care being taken not to touch the drawing, and plunged again into the first trough of pure water. Next, the apparatus and the bottle having been previ¬ ously prepared, made very clean, and the bottle filled with distilled water, the plate is withdrawn from the trough, and being instantly placed upon the inclined plane, distilled water, hot, but not boiling, is made to flow in a stream over its whole surface, carrying away every remaining portion of the saline wash. If hyposulphite has been used, the distilled water need not be so hot, as when common salt has been em¬ ployed. Not less than a quart of distilled water is required, when the design is, in its dimensions, eight and a half by six and a half inches. The drops of water, remaining on the plate, must be removed by forcibly blowing upon it, for otherwise, in drying, they would leave stains on the drawing. Hence, also, will appear the necessity of using very pure water; for if, in this last washing, the liquid con¬ tain any admixture of foreign substances, they will be de¬ posited on the plate, leaving behind numerous and per¬ manent stains. To be assured of the purity of the wa¬ ter, let a drop fall upon a piece of polished metal; evaporate by heat, and if no stain be left, the water is pure. Distilled water is always sufficiently pure, without this trial. After this washing, the drawing is finished ; it remains only to preserve it from the dust, and from the vapors that might tarnish the silver. The mercury, by the ac¬ tion of which the images are rendered visible, is par¬ tially decomposed ; it resists washing, by adhesion to tlw silver, but cannot endure the slightest rubbing. II. 31 XII. 362 APPENDIX. To preserve these sketches, then, place them in squares of strong pasteboard, with a glass over them, and frame the whole in wood. They are thenceforth unalterable, even by the sun’s light. In travelling, the collector may preserve his sketches in a box ; and, for greater security, may close the joints of the lid with a collar of paper. It is necessary to state, that the same plate may be em¬ ployed for several successive trials, provided the silver be not polished through to the copper. But it is very im¬ portant, after each trial, to remove the mercury immedi¬ ately, by using the pumice powder with oil, and changing the cotton frequently during the operation. If this be neglected, the mercury finally adheres to the silver ; and fine drawings cannot be obtained, if this amalgam be pres¬ ent. They always, in this case, want firmness, neatness, and vigor of outline, and general effect. A number of experiments, with prepared paper, have been made by different individuals, with various degrees of success, in Great Britain. From among the notices of these experiments, as they have appeared in different journals, the following selections have been made. In the spring of 1834, Mr. Talbot began a series of experiments, with the hope of turning to useful account the singular susceptibility evinced by the nitrate of silver, when exposed to the rays of a powerful light. He says, “ In the course of my experiments directed to that end, I have been astonished at the variety of effects, which I have found produced, by a very limited number of differ¬ ent processes, when combined in various ways ; and also, at the length of time, which sometimes elapses, before the full effect of these manifests itself with certainty. For I have found, that images formed in this manner, which have appeared in good preservation, at the end of twelve months from their formation, have nevertheless somewhat altered, during the second year.” He was in¬ duced, from this circumstance, to watch more closely the progress of this change, fearing that, in process of time. PHOTOGENIC DRAWING. 363 all his pictures might be found to deteriorate. This, how ever, was not the case, and several have withstood the action of the light, for more than five years. The images, obtained by this process, are themselves white, but the ground is differently and agreeably color¬ ed ; and, by slightly varying the proportions, and some tri¬ fling details of manipulation, any of the following colors were readily obtained; light blue, yellow, pink, brown, black, and a dark green, nearly approaching to black. The first objects, to which this process was applied, were leaves and flowers, which it rendered with extraor¬ dinary fidelity, representing even the veins and minute hairs with which they were covered, and which were fre- (juently imperceptible, without the aid of a microscope. ^Ir. Talbot goes on to mention, tliat tbe following con¬ siderations led him to conceive the possibility of discov¬ ering a preservative process. Nitrate of silver, which has become darkened by exposure to the light, is no lon¬ ger the same chemical substance as before ; therefore, if chemical re-agents be applied to a picture, obtained in the manner already mentioned, the darkened parts will be acted upon in a different manner from those which re¬ tain their original color, and, after such action, they will probably be no longer afl’ected by the rays of the sun, or, at all events, will have no tendency to assimilate by such exposure ; and, if they remain dissimilar, the pic¬ ture will continue distinct, and the great difficulty be over¬ come. The first trials of the inventor, to destroy the suscepti¬ bility of the metallic oxide, were entirely abortive ; but he has at length succeeded, to an extent equal to his most sanguine expectations. The paper, employed by Mr. Talbot, is superfine writing-paper; this is dipped into a weak solution of common salt, and dried with a towel, till the salt is evenly distributed over the surface; a solu¬ tion of nitrate of silver is then laid over one side of the paper, and the whole is dried by the heat of the fire, it is, however, necessary to ascertain, by experiment, the exact degree of strength requisite in both the ingredi¬ ents ; for, if the salt predominates, the sensibility of the 364 APPENDIX. paper gradually diminishes, in proportion to this excess, till the effect almost entirely disappears. In endeavoring to remedy this evil, Mr. Talbot discov¬ ered, that a renewed application of the nitrate not only obviated the difficulty, but rendered the preparation more sensitive than ever ; and, by a repetition of the same pro¬ cess, the mutability of the paper will increase to such a degree, as to darken of itself, without exposure to the light. This shows, that the attempt has been carried too far, and the object of the experimentalist must be to ap¬ proach, without attaining this condition. Having prepar¬ ed the paper, and taken the sketch, the next object is, to render it permanent, by destroying the susceptibility of the ingredients for this purpose. Mr. Talbot tried am¬ monia, and several other re-agents, with little success, till the iodine of potassium, greatly diluted, gave the desired result: this liquid, when applied to the drawing, produ¬ ced an iodine of silver, a substance insensible to the ac¬ tion of light. This is the only method of preserving the picture in its original tints; but it requires considerable nicety, and an easier mode is sufficient for ordinary pur¬ poses. It consists in immersing the picture in a strong solution of salt, wiping off tlie superfluous moisture, and drying it by the heat of the fire ; on exposure to the sun, the white parts become of a pale lilac, which is per¬ manent and immovable. Numerous experiments have shown the inventor, that the depth of these tints depends on the strength of the solution of salt. He also mentions, that those prepared by iodine become a bright yellow, un¬ der the influence of heat, and regain their original color, on cooling. Without the application of one of these preserv¬ atives, the image will disappear, by the action of the sun ; but, if enclosed in a portfolio, will be in no danger of altera¬ tion : this, Mr. Talbot remarks, will render it extremely convenient to the traveller, who may take a copy of any object he desires, and apply the preservative at his leisure. In this respect, Mr. Talbot’s system is superior to that of M. Daguerre, since it would be scarcely possible for a traveller to burden himself with a number of metallic plates, which, in the latter process, are indispensable. PHOTOGENIC DRAWING. 365 An advantage of equal importance exists in the rapid¬ ity with which Mr. Talbot’s pictures are executed; for which half a second is considered sufficient; a circum¬ stance that gives him a better chance of success in delin¬ eating animals, or foliage.— Foreign Quarterly Review. JYotice of a cheap and simple method of preparing pa¬ per for Photograpic Drawings in which the use of any salt of silver is dispensed icith : by Mungo Ponton, Esq., F. R. S. E., Foreign Secretary Society of Arts for Scotland. Communicated by the Society of Arts.* While attempting to prepare paper with the chromate of silver, for which purpose I used first the chromate of potash, and then the bichromate of that alkali, I discov¬ ered, that, when paper was immersed in the bichromate of potash alone, it was powerfully and rapidly acted on by the sun’s rays. It accordingly occurred to me, to try paper so prepared, to obtain drawings, though I did not at first see how they were to be fixed. The result ex¬ ceeded my expectations. When an object is laid in the usual way on this paper, the portion exposed to the light speedily becomes lawny, passing more or less into a deep orange, according to the strength of the solution, and the intensity of the light. The portion covered by the ob¬ ject retains the original bright yellow tint, which it had before exposure, and the object is thus represented yellow upon an orange ground, there being several gradations of shade, or tint, according to the greater or less degree of transparency in the difierent parts of the object. In this state, of course, the drawing, though very beau¬ tiful, is evanescent. To fix it, all that is required is careful immersion in water, when it will be found that those portions of the salt, which have not been acted on by the light, are readily dissolved out, while those which have been exposed to the light are completely fixed in the paper. By this second process, the object is obtained white, upon an orange ground, and quite permanent. If exposed, for many hours together, to strong sunshine, the • Read before the Society of Arts for Scotland, 29th May, 1889. 31 * 366 APPENDIX. color of the ground is apt to lose in depth, but not more so than most other coloring matters. The action of light, on the bichromate of potash, dif¬ fers from that upon the salts of silver. Those of the lat¬ ter, which are blackened by light, are of themselves in¬ soluble in water ; and it is difficult to impregnate paper with them, in an equable manner. The blackening seems to be caused by the formation of oxide of silver. In the case of the bichromate of potash, again, that salt is ex¬ ceedingly soluble, and paper can be easily saturated with it. The agency of light not only changes its color, but deprives it of solubility, thus rendering it fixed in the pa¬ per. This action appears to me to consist in the disen¬ gagement of free chromic acid, which is of a deep red color, and which seems to combine with the paper. This is rendered more probable, from the circumstance, that the neutral chromate exhibits no similar change. The active power of the light, in this instance, resides principally in the violet rays, as is the case with the black¬ ening of the salts of silver. To demonstrate this, three similar flat bottles were filled, one with ammoniuret of copper, which transmits the violet rays, one with bichro¬ mate of potassa, transmitting the yellow rays, the third, with tincture of iodine, transmitting the red rays. The paper was readily acted on through the first, but scarcely, if at all, through the seconc and third ; although much more light passed through the bottle filled with bichromate of potassa, than through the one filled with ammoniuret of copper. The best mode of preparing paper with bichromate of potash is, to use a saturated solution of that salt; soak the paper well in it, and then dry it rapidly, at a brisk fire, excluding it from daylight. Paper, thus prepared, acquires a deep orange tint, on exposure to the sun. If the solution be less strong, or the drying less rapid, the color will not be so deep. A pleasing variety may be made, by using sulphate of indigo along with the bichromate of potash, the color of the object, and of the paper, being then of dift'erent shades i PHOTOGENIC DRAWING. 367 of green. In this way, also, the object may be repre¬ sented of a darker shade than the ground. Paper, prepared with bichromate of potash, is equally sensitive with most of the papers, prepared with salts of silver, though inferior to some of them. It is not suffi¬ ciently sensitive for the camera obscura, but answers quite well for taking drawings from dried plants, or for copying prints, &c. Its great recommendation is, its cheapness, and the facility with which it can be prepared. The price of the bichromate of potash is '2s. 6d. per lb., whereas, of the nitrate of silver, only half an ounce can be obtained for that sum. The preparing of paper, with the salts of silver, is a work of extreme nicety, whereas, both the preparing of the paper with the bichromate of potash, and the subsequent fixing of the images, are matters of great simplicity; and I am therefore hopeful, that this method may be found of considerable practical utility, in aiding the operations of the lithographer.— Jameson’s Journal^ Jlpril to July^ 1839. 4 *.-^ • ' -:v /' V ^ ■ ., r-- • ♦ • ^ . - t; GLOSSARY. Many words, not contained in this Glossary, will be found de« fined or described, in the body of the Work, in their proper places. For these, see Index. Acescent, becoming sour. Acetate, a salt, containing acetic acid. Acetic acid, a vegetable acid which exists in vinegar. Acetous, having the character of vinegar. Acetous fermentation, the fermentation which produces vinegar. Acicular, shaped like needles. Acid, a substance, or fluid, which turns vegetable blues to a red, and forms saline compounds with alkalies, &c. Most of the acids con¬ tain oxygen. Albumen, a fluid found in living bodies, which coagulates by heat. White of egg is an example. Alkali, a substance in chemistry, which turns vegetable blues to a green, and combines with acids, forming salts. Alloy, a compound of difterent metals. Alumine, an earth, which exists in clay, alum, &c. Aluminium, a metal, which is the basis of alumine. Amalgam, a compound of mercury with another metal. Ammonia, volatile alkali. Amorphous, not having a determinate or certain form. Argillaceous, containing clay, or resembling it. Argillaceous schist, cotmnon slate. Arseniuret, a compound with arsenic. Barilla, the ashes of certain maritime plants. Barometer, an instrument for measuring the weight of the atmosphere. Base, an ingredient in a chemical compound. Thus, sulphuric acid is found combined with various bases, such as soda, magnesia, &c. Bichloride, a double chloride. A compound, having two proportionals of chlorine. Boracic acid, a compound of oxygen and boron, which last is a simple combustible substance. Borates, compounds of boracic acid with a base. Brake, or Break, a lever, which is occasionally pressed down upon the wheel of a carriage, to retard its velocity. Bromide, a compound of bromine and some other substance. Bromine, an elementary substance, related to iodine and chlorine, and found in sea water. 370 GLOSSARY. Camera lucida, ) optical instruments, by which the images of ob- Camera obscura,\ iecia, as, for example, buildings or trees, are thrown upon a paper, or other plane surface. Carbonaceous, containing carbon or coal. Carbon, a simple inflammable body, forming the principal part of wood and coal, and the whole of the diamond. Carbonate, a compound or a salt, containing carbonic acid. Carbonic acid, a compound gas, consisting of carbon and oxygen. It has lately been obtained in a solid form. Carbonic oxide, a gas composed of carbon combined with the smal¬ lest quantity of oxygen. Carbonization, conversion into coal. Carburetted hydrogen, a gas, composed of carbon and hydrogen ; as coal gas. Carburet, a name given to certain compound substances, of which carbon forms a part. Caseous, having the consistence of cheese. Centre of gravity, that point in a body, about which all the parts are equally balanced. Centrifugal, tending to fly off from the centre. Chloride, a compound of chlorine and some other substance. Chlorine, a simple substance, formerly called oxymuriatic acid. In its pure state, it is a gas, and, like oxygen, supports the combustion of some inflammable substances. Chromate, a combination of chromic acid. Chromium, a brittle metal, of a yellowish white color. Chromic acid, an acid of which chromium is the basis. Chromate, a compound of chromic acid with some other substance, or base. Clay schist, common slate. Cohesive attraction, the force by which the particles of a body cohere together. Coluber, a snake, having plates on the belly and scales on the tail. Comparative anatomy, the science which treats of the structure of other animals, compared with that of man. Concentric, having the same centre. Conic sections, the curves produced by cutting across a cone, in difler- ent directions. Cupreous, containing copper. Cycloid, the curve described by a point in the circumference of a cir¬ cle, while the circle rolls along a straight line. Cylinder, a figure with circular ends and straight, parallel sides. A round ruler and a wafer box are rough examples of the cylindrical shape. Debris, fragments, or remains, of disintegrated rocks. Deliquescent, dissolving by fluid absorbed from the atmosphere. Disintegrated, broken up or crumbling, for the most part, by the ac¬ tion of air and moisture. Eccentric, or excentric. This term is applied to a wheel, the axis of which is not in its centre. Effervescence, a motion resembling boiling. GLOSSARY. 371 Ejiorescence, the conversion of crystals" into powder by the loss of their water of crystallization. Electro-magnetism, a science which shows the connexion of elec¬ tricity and magnetism. Epicycloid, the curve described by a point in the circumference of one circle, while rolling upon the circumference of another. Flange, or Flanch, a rim, or part projecting from the whole circum¬ ference. Flanges are used in the wheels of rail-road cars, to pre¬ vent them from slipping off the track ; also, at the ends of iron pipes, to enable them to be screwed together. Flocculent, resembling locks of down, or cotton. Fluate of lime, or Fluor spar, lime combined with fluoric acid. At Derbyshire, in England, it is found in crystalline masses, beautifully variegated with purple. Flush, even, or in the same surface. Friction, the rubbing of surfaces together. Friction rollers, little wheels, or cylinders, used to diminish friction. Fulcrum, the point of support on which a lever rests. Gallaie, a salt, formed of gallic acid and a base. Gallic acid, an acid obtained from nutgalls. Gear, the teeth of wheels, by which one moves another. Gelatin, an animal substance which is dissolved by hot water, and which forms common glue. Geognostic, appertaining to a knowledge of the earth’s structure. Geological strata, the natural layers which are met with in penetra¬ ting the earth. Gneiss, stratified granite. Gobelins, the name of a celebrated manufactory of tapestry in Paris , so called, after two brothers of that name, who founded the manufac¬ tory in the reign of Francis I. Gravity, the general property by which bodies are attracted towards each other, as seen in a stone falling towards the earth. Graywacke, a kind of rock, of a gray or brown color, composed of grains and fragments of difl’erent materials. Hrematite, an ore of iron. Hydrate, a solid compound with water. Hydrate of lime, a solid compound of lime with water. Hydraulics, the science which treats of the motion of fluids. Hydraulic cement, mortar,which hardens underwater. Hydrochlorate, a salt containing hydrochloric, or muriatic, acid. Hydrochloric acid, see Muriatic acid. e e Hydrodynamics, the science which treats of the power or force of water. , . . • • _ Hydrogen, a very light, inflammable gas, of which water is, in part, composed. It is used to inflate balloons. ^ ^ Hydrostatic pressure, the property of fluids by which they press equally in all directions. r a -j Hydrostatics, the science which treats of the pressure of fluids. Hydrosulphuret, a compound of hydrogen and sulphur with another body. Hyperbola, one of the conic sections. 372 GLOSSARY. Hyposidphile, a combination of hyposulphurous acid with a case ; a», for example, with soda. Inclination, slant, slope, or obliquity. Inertia, the tendency which a body has to continue at rest, or to move in a straight line, if it moves at all. Infiltration, the penetration of a fluid into the pores of a solid, as in soaking. Infusion, a solution of a vegetable substance, made without boiling. Initial, that which exists at the first moment. Primary, incipient. Inspissated, thickened, as when the juice of a plant is partly dried. Iodine, a simple substance, of a grayish black color, and metallic lus¬ tre, having a violet-colored vapor. It is obtained from marine plants. Iridium, a metal, found in minute quantities in the ores of platinum. Kelp, the ashes of seaweed. Larvae, the name given to certain insects in their primary state, be¬ fore they acquire wings ; as the caterpillar. Litharge, an oxide of lead partly vitrified, or converted into glass. Magnesia, a kind of earth, light and white, with alkaline propertiesw MalacHite, an ore of copper. Malic acid, a vegetable acid which exists in cider. Minimum, the smallest quantity. Momerdum, the force possessed by a body in motion, made up of its weight and velocity. Muffle, a vessel resembling a little oven, placed in furnaces to contain crucibles and other objects, which require to bo protected from smoke and ashes. Muriate, a salt, containing muriatic or hydrochloric acid. Muriatic acid, an acid, composed of chlorine and hydrogen ; called, also, hydrochloric acid, and spirit of salt. JSTitrate, a salt, containing nitric acid. JVitric acid, an acid composed of oxygen and nitrogen, JMitrogen, or azote, a simple substance, which exists, in the form of gas, in the atmosphere. It does not support respiration nor flame. Ochre, an earth colored yellow or red by oxide of iron. Ochreous, containing ochre. Orrery, a machine, constructed to show the motions of the heavenly bodies. Osmium, a metal, found in minute quantities in the ores of platinum. Oxalic acid, a vegetable acid which exists in sorrel. Oxidable, capable of being oxidized. Oxidation, combination with oxygen ; as in the rusting and tarnishing of metals. Oxide, a compound (which is not acid) of a substance with oxygen :— Example, oxide of iron. Oxygen, a simple and very important substance, which exists in the atmosphere, and supports the breathing of animals and the burning of combustibles. Oxymuriatic acid, see Chlorine. Parallelogram, an oblong square. Parallelepiped, a solid body, of which the four sides are parallelo¬ grams, and the two ends square. GLOSSARY. 373 Piles, large wooden posts or timbers, driven into the mud, to support bridges and other structures. Piling engines, engines for driving piles. Plasticity, the property or capacity of being moulded. Pontoon, a kind of flat-bottomed boat, used to support bridges, float¬ ing machinery, &c. Potass, an alkali, composed of potassium and oxygen. Potassium, a light and very inflammable metal, discovered in potass, by Sir H. Davy. Power of a number, the product obtained by multiplying a number by itself. The product obtained by the first multiplication is called the square. If this be again multiplied by the same number, it gives the cube ; and so on, for the higher powers. Precipitation. When a substance, dissolved in a liquid, is afterwards separated, in a solid state, by the addition of another substance, it is said to be precipitated. Purple of Cassius, a purple powder, precipitated from a solution of gold. Pyrites, a compound of a metal with sulphur, having a metallic lus¬ tre, and often crystallized. Pyritous, having the charactes of pyrites. Pyrometer, an instrument for measuring high degrees of heat, as in furnaces, &c. Radicles, small roots. Radius, a line drawn from the centre of a circle to its circumference. Reticulated, resembling the appearance of a net. Rhodium , a metal found in minute quantities in the ores of platinum. Salt, a compound, produced by the union of an acid with a base. Saturated solution, a liquid, holding so much of a substance dissolv ed, that it can dissolve no more. Scalpel, a dissecting knife. Schist, or Schistus, slate. Sector of a circle, a part contained between two radii and an arc. The sector of a cylinder is a longitudinal part which bears the same relation to the whole, as a sector does to a circle. Silica, or silex, an earth which exists in flint, sand, &c. Silicium, a metal, or simple substance, which is the basis of silica Sinuosities, wmdings. Soda, an alkali, obtained from the ashes of marine plants. Spar, a general name given to crystallized minerals. Stanniferous, containing tin. Stratification, disposal in layers. Stratum, plural strata, a layer of earth, rock, or other mineral sun- stance. Striated, marked with fine parallel lines. Sulphate, a salt, containing sulphuric acid. Sulphur, or brimstone, a simple, inflammable substance, well knowa Sulphurel, a compound of sulphur with another body. Sulphuretted hydrogen, a gas, composed of sulphur and hydrogen. Sulphuret of carbon, a compound of sulphur and carbon. Sulphuric acid, an acid composed of oxygen and sulphur. II. 32 XII. 374 GLOSSARY. Summit level, the highest part of a canal, or rail-road. Tangent, an external straight line, which touches, but does not cross, a circle. Tartaric acid, a vegetable acid which exists in wine. Thermce, baths of the Romans, which were large and magnificent buildings. Thermal waters, warm or hot springs. Thermometer, an instrument, for measuring heat. Traction, the act of drawing a load. Draught. Treenails, (pronounced trunnels,) the wooden pins which confine the planking to the sides of vessels. Also, simUar pins, employed for other purposes. Vacuum, empty space. A perfect vacuum is rarely, if ever, pro¬ duced. The vacuum of the air pump, and that of the barometer, are approximations only, in which some gas or vapor is present. Vaporization, conversion into vapor, commonly at a boiling temper¬ ature. Velocipede, a carriage with two wheels, one before the other, on which a person rides, pushing himself forward with his feet. Viaduct, a piece of masonry built across a stream or valley, to support a road, or a rail-way. Vice versa, the side being changed, or the question reversed. , Vitreous, glassy. Water-joint, a movable joint, made so tight as to exclude water INDEX TO VOLUME II. A. Accumulated veios, 284. Adjustment of sails for windmills, 98. Adzes, 246. Aerial ascents in balloons, 49. Aerostation, 48. Ahaz, sun-dials in the time of, 187. Aids to locomotion, 12. Air, escape of, and of water, through a hole, 88. See Atmos¬ phere. Air-boxes for water pipes, 140. Air-pumps of steam-engines, 118. Albany, facts as to, 309. Basin of the Erie canal at, 310. Albany and Schenectady rail-way, cost of the, 325. Alkalies, in glass, 248. Alleghany Mountains, passes across the, 331. Alleghany rail-way, 299, 334. Facts respecting the, 328. See Rail-ways. Alloys, of metals, 211. Of gold, 214. Experiments of Hatchet and Cavendish with, 216, note. With silver, 219. Brass, 223. Bronze, 225. Gun-metal, 225. Bell-metal, 226, 226. Specu¬ lum-metal, 225, 226. Alternate, or reciprocating, motion, 62. Amaleams, 211. Gold extracted by, 212. Amboy and Camden rail-road, 322, 334. American, enterprise, 298. Rail¬ ways, 298, 299, 318, 334. Ca¬ nals, 299, 301, 314. Ancient coins, experiments on, by Dize, 226, note. Animal power, 82. Of men, 82. Of horses, 84. Animals, motion of, 9, 10. Annealing, metals, 216, note. Glass, 251. Antimony, used for coloring glass, 258. Localities of, 287. Appendages to steam-engines, 110. Apron, 87. Aqueducts, canal, 33, 304. Con¬ veying of water in, 135. Ro man, 136. Arbor, meaning of, 195, note. Arch of the Schuylkill bridge, 22. Archimedes’ screw, 144. Arcs, line of, described in walk ing, 10. Arkwright, Sir Richard, water spinning-frame by, 168. Arrago, experiments by, on steam, 102, note. Arrangement of pipes, 156. Arrow-headed character, 263. Artesian wells, 275. Operations in forming, 276. Cause of the overflowing of, 276. Tools used in digging, 277. Finish¬ ing of, 278. Artificial, fountains, 161. Gems, 258. Artillery, metal for, 226. Artois, overflowing wells in, 276. Arts, of locomotion, 9. Moving forces used in the, 81. Of con- 376 INDEX. veying water, 135. Of com¬ bining flexible fibres, 164. Of horology, 187. Of metallurgy, 208. Of vitrification, 247. Of induration by heat, 262. Ascents in balloons, 49. Assaying metallic ores, 210. Athens, sun-dials on the Tower of the Winds at, 188. Brick walls of, 262. Atmosphere, effect of, on overshot wheels, remedied, 88. Pres¬ sure of, upon steam, 101, 102. See Air. Atmospheric elastic force, 104. Atmospheric engine of Newco¬ men, 115, 120. Atmospheric machines, 159. Attaching of horses, 14, 18, 84. Augusta and Charleston rail-road, 322. Cost of the, 325. Axes, 244, 246. Axis, meaning of, 195, note. Axle, meaning of, 195, ?iote. Axletrees, 17. B. Babylon, the walls of, brick, 262. Back-water, remedies for, 92, 93. Bag pumps, 153. Balance-wheels of watches, 191, 192, 203. Ballast, of a ship, 41. Of balloons, 48. Balloons, 48. Ascents in, 49. Baltimore and Ohio rail-way, 325, 335. Baltimore and Washington rail¬ way, 320, 335. Band, 73. Band wheels, 51. Bar-iron, 235. Barker’s mill, 96. Barrels, of watches, 191,200,201. Of clocks, 195, 197. Barton’s pistons, 122. Basin of the Erie canal, at Alba¬ ny, 310. Baskets, plated, 222. Batchelder, loom by, for weaving twilled fabrics, 176. Bath-metal, 224. Baths, Parkes’s metallic, 244. Roman, of brick, 262. Batter, cotton, 169. Batting cotton, 169. Bayonets of couplings, 76. Bead pumps, 157. Beak iron, 245. Beam, wind upon the, 39. Beating, gold, 215. Beet sugar, manufacture of, 339 ; cleansing of the beet roots, 339 ; rasping the beets, 341 ; extrac¬ tion of the juice, 342 ; mode of operating with the press, 343 ; defecation of the juice, 343 ; concentration of the juice, 344. Clarifying, 344. Filtration, 346. Belgium, rail-way in, 318. Bell-metal, 225, 226. Belt and segment, 71. Bernouilli, oblique planes recom¬ mended by, 42. Berthier, alloy produced by, 242. Besant’g wheel, 93. Bevel-gear, 56. Biddery-ware, 229. Binding, See Bookbinding. Birds, the flying of, 10. Swim¬ ming of, 11. Biscuit, in pottery, 270. Bismuth, localities of, 287. Blades of cutlery, 245. Blair’s gap, pass through, 331. Blanks, in coining, 219. Blast, hot, in smelting furnaces, 233. Blasting, with gunpowder, 134, 292. Tools of miners for, 290. In mines, 292. Sawdust used in, 293. Blast-furnaces, 232. Bleaching rags for paper, 184. Blistered-steel, 240. Block-tin, 229. Blooms, 236. Blotting paper, 184. Blowing glass, 250. Blow-valves, 118. Boats, transferring, on canals, 3* INDEX. 377 Canal, 36. Powers in, which act against the inertia of water, 42. Passenger canal, 306. Bobbins, 171, 172. Bohemia, rail-way in, 318. Boilers of steam-engines, 108. Strongest form for, 108. Flue, 108. In large low-pressure en¬ gines, 109. Bursting of, 112. Other forms for, 113. Mate¬ rials for, 117. Bologna-phials, 251. Bonnet, glass fibres obtained by, 261. Bookbinding, the process of, 185. Cloth, 186. Borers, use of, in digging Artesian wells, 277. Used by miners, 290, 297. Bosses, 245. Bossut, on the inclination of fioat- boards, 92. Boston and Lowell Railroad, 319, 334. Boston and Providence rail-road, 321, 334. Boston and Worcester rail-road, 327, 334. Bottle-glass, 252. Boulton, coining machinery by, 220 . Bow of a ship, 38. Bowing materials for hats, 183. Boxes, pump, 148. Brakes, retarding wheels by, 31. Of a pump, 148. Bramah, re-inventor of the hy¬ drostatic press, 152. Lead pipes by, 228. Bramins, sun-dials among, 187. Branca, engine of, 103, note. Brass, composition of, 223. Man¬ ufacture of, 224. Buttons, 224. Pins, 225. Brathwaite and Ericsson’s steam- engines, 113. Breakers, in carding machines, 170. Breast-wheels, 85, 94. Brewster, Dr., on the adaptation of wheels to falls, 88, noie. 32 * Brick-kilns, 264. Bricks, ancient, 262. Modern, 263. Pressed, 263. Burning of, 264. Bridges, 21. Wooden, 21. The Schuylkill, 22. Stone, 22. Cast-iron, 23. Suspension, 23. At Menai, 23, 125. Floating, 23. Bridgewater, Duke of, tunnel in the canal of the, 34. British Queen steam-ship, 45. Broadcloths, nap of, 182. Broad glass, 251. Broad wheels, 15. Bronze, 225. Brooklyn and Jamaica rail-road, 322,334. Cost of iron for, 324, Sleepers on the, 324. Brown’s gas engines, 128. Brush wheels, 58. Brussels, watch-spring preserved at, 190. Brussels carpets, 178. Buchanan, on the application of human power, 83. Buckets, of overshot wlieels, 86. Of chain wheels, 89. In breast wheels, 95. Buffalo and Niagara rail-road, 321, 334. Burning, of bricks, 263, 264. Of pottery, 269. Burns, buckets of, in the overshot wheel, 87. Method of getting rid of back-water by, 92. Bursting of boilers, 112. Bushnell’s machine for submarine navigation, 47. Buttery, on carbon in steel, 241, note. Buttons, manufacture of brass, 224 ; of the eye or shank, 224. White-metal, 224. Brass-eyes of pearl, 224. C. Cables, 166. Caledonian canal, 36. Camden and Amboy rail-way, 322 , 334. 378 INDEX. Camera obscura, use of the, in photogenic drawing, 356. Cams, 63. Curves for, 64, note. Canal boats, 36. On the Erie canal, 305. Passenger, 306. Canals, rail-roads and, 24. Feed¬ ers of, 32. Embankments of, 32. Aqueducts in, 33, 304. Tun¬ nels for, 33. Gates and weirs for, 34, 308. Locks in, 34, 303, 308. Economizing water in, 35. Boats for, 36, 305, 306. Size of, 36. The Great Dutch, 36. The Caledonian, 36. Languedoc, 37, 301. New York, or Erie, 37, 300, 308, 315. In the United States, 298, 314 ; their extent, 299 ; routes of the principal, 300. Historical facts respecting, 301. Length of the American, 301, 314 ; their cross-sectional area, 302. Ve¬ locity of wave in, 302. Dis¬ similarity in American and Brit¬ ish, 303. Suspension of the American, in winter, 305; mode of travelling on them, 306. Slackwater-navigation in the lines of, 307. Details respec¬ ting the Erie, 308, 315. The Morris, 311, 315. Table re¬ specting the United States’, 314. Eastern division of the Pennsyl¬ vania, 315, 330. Cannon, casting of, 239. Cannon-balls, 234. Cannon-pinion of watches, 206. Carats of gold, 214. Card-ends, 171. Carding, 170. Carpets, Kidderminster, 177, 178. Venetian, 178. Brussels, 178. Turkey, 179. Carriages, 12. Retarding, 31, note. Steam, 129. Carronades, manufacture of, 239. Cartridges, use of, in mining, 292. Cartwright’s steam-engine, 67, 122 . Case-hardening, 242. Casting, the process of, 233. Moulds for, 233. Chill, 234. Of glass, 253. Of pottery, 269. Cast-iron, bridges of, 23. Con¬ dition of, 233. Converted into good steel, 246. Rails, intro¬ duced, in Great Britain, 318. Cast-steel, 241. Cavendish experiments with al¬ loys, 215, note. Cayuga canal, 308, 315. Cellular pumps, 157. Cementation, of gold, 214. Of steel, 240. Cenis, Mount, and Simplon, 298. Centre-wheel of a watch, 203. Centres, line of, 54. Centrifugal pumps, 146. Ceramie, crystallo, 260. Chain, wheels, 88. Pumps, 157. Chains of watches, 190, 191, 200, 201 . Chairs on rail-ways, 25. Champlain canal, 308, 315. Change, of velocity, in machinery, 60. Of direction, in motion, 74. Chariots, 12. See Carriages. Charleston and Augusta rail-way, 322. Cost of the, 325. Chat Moss, rail-way across, 323. Cheeks of rail-road chairs, 322 Chemung canal, 308, 315. Chill-casting, 234. Chinese, substitute for canal locks by, 35. Working of pumps by, 157. Make ropes of woody fibres, 166. Sun-dials known to the, 187. Pakfong, or white copper, 226. Drawings on por celain by the, 270. Porcelain, 271. Magic porcelain of the, 273. Choragic monument of Lysicrates, 265. Chrome, used for coloring glass, 258. Church, Edward, compilation from a work of, on beet sugar, 339. Circles, the moving of horses in, while drawing, 85. INDEX. 370 Circular motion, 51. Distant, 69. In Barker’s mill, 96. Circumferences, primitive, 54. • Clack valves, 122. Clamps of bricks, 264. Clarification of beet sirup, 344. Clay, valuable properties of, 262. Products from indurated, 262. Pipe, 267 Claying-bars, 291. Cleansing beets for sugar, 339. Clepsydra, construction of the, 188. Invented in Egypt, 188, note. Brought to Rome from Athens, 188, note. Clocks, 189. Water, 189. Gene¬ ral principles of, 190. Maintain¬ ing power of, 190. Weights of, 190, 196. Regulating move¬ ment of, 191. Pendulums, 191, 195. Scapeinents of, 193. De¬ scription of, 194. Going part of, 194. Striking part of, 194, 197. Wheel-work of, 194. Dial-work of, 194. Barrels of, 195, 197. Pallets in, 196, 198. Hands of, 196. Hawksbill in, 198. Warning-pieces in, 198. Close-hauled, 39. Cloth-binding of books, 186. Cloths, woollen, manufacture of, 181. Felting, 182. See Cotton. Clutches to couplings, 76. Coals, mechanical virtue of, 125. Coal-strata, 279. Cobalt, used for coloring glass, 258. Printing ware with the oxide of, 270. Furnished to Chinese potters, 270, note. Pla¬ ces for finding, 287. Coffer-dams, 22. Coffer-valves of steam-engines, 117. Coining, of silver and other me¬ tals, 219. At the mint in Eng¬ land, 220. Of medals, 220. Coin-posts, for canal-gates, 35. Coins, experiments of Dize on an¬ cient, 226, note. Copying, by voltaic electrical engraving, 349. Colcothar, polishing silver with, 219. Polishing cutlery with, 246. Colors for staining glass, 266, 258. Columbia and Philadelphia rail¬ road, 321, 329, 334. Combining flexible fibres, arts of, 164. Combs in carding machines, 170. Common pinion in watches, 205. Common pumps, 147. Compass, magnetic, used by mi¬ ners, 289 ; dial of, 289. Concentration of beet juice, 344. Concretions, in geology, 280. Condensation, application of steam by, 104, 120. Condensers, invented by Watt, 116, 120. Remarks on, 118, 120. Treadwell’s, 121. Condensing engines, boilers in, 108, 109. Construction of, 115. Conducting water, 135. By aque¬ ducts, 135. By water pipes, 136. By syphons, 141. Conemaugh river, viaduct across the, 332. Cones, 60. Consolidated mines, depth of the, 298. Continued rectilinear motion, 73. Contrate wheels, 56. Of watches, 203. Convoys, retarding by, 31. Copper, gold alloy, 215, and 215, note. Gilding on, 216. Plating on, 221. Extraction of, 222. Mines of, 222. Working, 223 Tinning, 223. Articles mada of, 223. An alloy in brass, 223 ; in bronze, 225. White, 226. Used for coloring glass, 258. Places for finding, 286. Copper pipes, 137. Cordage, 155. See Ropes. Cornwall, steam-engine at St. Austle in, 125. Depth of mines in, 298. Cost of .American rail-ways, 325, 326 ; of English, 325. 380 INDEX. Cotton, manufacture of, 167; ele¬ mentary inventions for the, 168. Batting, 169. Ginning, 169. Carding, 170. Drawing, 170. Roving, 171. Spinning, 172. Mule-spinning, 173. Warping, 174. Dressing, 176. Weaving, 175. Twilling, 176. Double weaving, 177. Cross-weaving, 177. Cotton rags, paper made of, 183. Counterpanes, 180. Couplings, 75. Clutches, or glands to, 76. Bayonets to, 76. Cranks, 59, 65. Crockery-ware, 265. Crompton, Samuel, invented the mule, 169. Crooked Lake canal, 308, 315. Crossing points in rail-ways, 28. Cross-weaving, 177. Crown-glass, 249. Crown-wheels, 56. Of watches, 204. Crucibles, materials for, 265. Crude-iron, 233. Cruikshanks, on water from com¬ bustion of gunpowder, 131. Crutch scapements, 72. Crystallo ceramie, 260. Culverts under canals, 33. Cupellation of gold, 213. Cupels, described, 213. Curb, in watches, 206. Cursor, Papirius, sets up a sun¬ dial at Rome, 188. Curves upon rail-ways, 28. Curves, for cams and wipers, 64, note. In pipes, to be avoided, 139, 140. Cut-glass, the operation of making, 255. Cutlery, 245. Grinding, 246. Pol¬ ishing, 246. Setting, 246. Cut-nails, 239. Cutting glass, 256. Cylinder-glass, 252. Cylindrical wheels, 17. Cyrrhestes, Andronicus, Tower of the Winds erected by, 188. D. Daguerre, description of photo¬ genic drawing by, 350. See Photogenic Drawing. Damascus swords, 244, note. Dams for slackwater-navigation, 306. Across the Schuylkill 307 ; the Hudson, 309. Danforth’s speeder, 172. Danville and Pottsville rail-road, 325, 336. Dartrigues, on devitrification, 259. Davy, Sir Humphrey, on procuring power from fluids, 128. Dead pulleys, 76. Dead water, 37. Dectot, Mannoury, 144. Deep cuts, 25. Defecation of beet juice, for sugar, 343. De La Hire’s pump, 161. Dent, on a dissected watch, 208. Deparcieux, M., on the line of traction, 15. Experiments by, on the inclination of float-boards, 92. Depots of American rail-roads. 328. Depth of mines, 297. Derangements, in mineral veins, 285. Desaguliers, on man’s and horse’s power, 84. Detonation of gunpowder, 130. Devitrification, 259. Dials, sun, 187. Of compasses used by miners, 289. Dial-work of a clock, 194. Diamonds, in watches, 207. Dilated, or flat, veins, 283, 284. Direction,change of, in machinery, 74. Of a mineral plane, 280. Disengaging machinery, 76. Disengaging process, in photogenic drawing, 358. Dishing wheels, 16, 17. Disseminated metalliferous sub¬ stances, 282, Distances, in the route from New York to New Orleans, 300. Distant rotary motion, 59. INDEX. 381 Diving-bells, 45. Account of, 45, 46. Sensations in, 46. Dize, experiments by, 226, note. Doffing-cylinders, 170. Doffing-plates, 170. Double-acting engines, description of, 116. Double-acting pumps, 153. Double-speeders, 171. Mechan¬ ism of, 171. Double-weaving, 177. Draught, line of, 14, 18, 84. Of a cotton machine, 171. Drawing, by animals, 15, 18, 84. Of cotton, 170. Wire, 238. See Photogenic drawing. Drawing-frames, 170, 171. Draw-looms, 177. Dressing, in weaving, 175. Drops, Rupert’s, 251. Drying of bricks, 262, 263. Dry-rot, Kyan’s preparation a- gainst, 324. Dublin and Kingstown rail-way, ^19. Cost of the, 325, 326. Ductility of glass, 260. Dulong, M., on steam, 102, note. Dust, on tram-roads, 29. Dutch canal, the great, 36, 302. E. Earth, means of penetrating into the, 290 ; manual tools, 290 ; gunpowder, 291 ; fire, 294. See Mines. Earthen, pipes, 137, note, 138. Ware,265 ; manufacture of,266. Eccentric, wheels, 63. Pumps, 155. Ecton mine, depth of, 298. Edge rail-ways, 25. Edges, silver, 221. Eduction-pipes, 118. Egyptians, the manufacture of linen by the, 181. Sun-dials known to the, 187. Clepsydra invented by the, 188, note. Glass among the, 261. Bricks of the, 262. See Pyramids. Electrical engraving, voltaic, 348. Elementary inventions for the cot¬ ton manufacture, 168. Elements of machinery, 50. Eliquation of silver, 218. Elongation, galleries of, 295, 297. Embankments of canals, 32. Enamelling glass, 257. Enamels for, 257. Coloring materials for, 258. Enchasing, 215. Endless screw, 57. Engaging and disengaging ma¬ chinery, 75. Engines, gas, 128. Magnetic, 134. Fire, 162. See Steam- engines. England, Artesian wells in, 275. Wooden tram-roads introduced into, 318. Cast-iron rails in¬ troduced in, 318. Cost of rail¬ ways in, 325. Engraving, voltaic electrical, 348. Enterprise, American, 299. Epicycloidal wheels, 69. Equalizing motion, 76. Ericsson’s and Brathwaite’s steam- engines, 113. Erie canal, 37, 300. Length of the, 300, 302, 315. Number of boats navigating the, 305. Facts respecting it, 308, 310, 315. Basin of the, 310. Etruscan vases, 273. European porcelain, 271. Evans, high-pressure expansion en¬ gines of, 106. Excavation, instruments for, 289. Means of, 290 ; manual tools, 290 ; gunpowder, 291 ; fire, 294. Forms of the, to be made, 295. See Mines. Expansion, application of steam- power by, 106, 119. Of glass, 261. Expansion engines, 119. Expansiveness of water in steam, 100 . Explosions of steam-boats, 112. Extraction, of metals, 209. Of gold, 212. Of silver, 217. Of copper, 222. Of lead, 226. Of tin, 229. Of iron, 232. Of beet juice for sugar, 342. Eyes of brass buttons, 221. 382 INDEX. F. Falls, adaptation of overshot wheels to, 88, 7iote. Faraday, experiments by, on steel, 241. Faults, in mineral veins, 285. Feed-pipes for steam-engines. 111. Feeders of canals, 32. Felting, hats, 182. Cloths, 183. Fen-wheels, 163. Ferrara, Andrew, tempering of swords by, 244, note. Ferry-boats, propulsion of, by horses, 85. Fibres, arts of combining flexible, 164. Woollen, 181. Of glass, 260, 261. Filling of a web, 175. Filtration of beet sirup, 346. Finishers, in carding machines, 170. Fire, employment of, in mining, 294. Fire-arms, properties of, 132. Fire-engines, 162. Fishes, the swimming of, 10. Swimming bladder in, 11, note. Flanges on rail-way wheels, 25i Flash-wheels, 163. Flat, or dilated, veins, 283, 284. Flax, reward offered for a machine to spin, 180. Flexible fibres, arts of combining, 164. Flint, use of, in glass-making, 248, 252. Glass ground with, 254. In Wedgewood’s ware, 268. Flint-glass, 252. Moulding, 254. Float-boards, propulsion of boats by, 42. Affixed to a chain, 89. In under-shot wheels, 90. Best number of, 91. Position of, 91, 94. Breadth of, 92. In Be- sant’s wheels, 93. In Lambert’s wheels, 94. In breast-wheels, 95. Floating bridges, 23. Floors, of tiles, 264. Flue-boilers ,in steam-engines, 108. Fly, 78. In the striking part of a clock, 197. Fly-wheels, 78. Of steam-en¬ gines, 117. Flying, locomotion by, 10 Foil, tin, 229. Followers, in moulds for pressing glass, 255. Force of gunpowder, 131. Forces, see Moving Forces. Forcing-pumps, 149. Forged-iron, 235. Forging, 235. Forks, 245. Prongs of, 245. Form of a ship, 37. Formations, geological, 279. Fountains, Hero’s, 140, 159. Ar¬ tificial, 161. Fourdrinier’s paper-machine, 184, 185. Fowling-pieces, manufacture of, 239. France, canals in, 37, 301, 303. Manufacture of porcelain in,271. Artesian wells in, 275. Rail¬ ways in, 318. Frenchtown and Newcastle rail¬ way, 320. Friction, locomotion opposed by, 9. Obviated, in walking, 10. Angle for obviating, in drawing, 15, l8, 84. In machinery, 79 Of pipes, 138. Frit, of glass, 250. Fritting glass, 250. Frost, prevention of, on rail-ways, 322. Fuel, of engines, 125. Used on rail-ways, 328. Fulling cloths, 181. Fulton, Robert, preferred planes to canal locks, 35. Introduc¬ tion of steam-navigation by, 42. Experiments by, on submarine navigation, 47. His torpedo, 48. Furnaces, in steam-engines, 116. Blast, 232. Puddling, 235. Fusees of watches, 62, 191,200— 202 . Fuses, used in blasting, 290. Fyfe, on the Chinese pakfong, 226. INDEX. 383 G. Gadg, used by miners, 290. Galena, 226. Galleries, in mines, 295. Acceler¬ ating the advance of, 296. Gallic coins, experiments on, by Dize, 226, note. Gangues, of metals,209. Of lodes, 282. Value of, to miners, 285, 288. Garnerin, M., parachute of, 49. Aerial voyage of, 49, note. Gas engines, 128. Gates, in canals, 34. Gathered, in glass-blowing, 250. Gathering-pallet in a clock, 198, 199. Gauge-cocks, in steam-engines, 111 . Gauze-weaving, 177. Gay-Lussac, ascension of, 49, note. Gear or gearing, meaning of, 53. Spur, 63.^ Spiral, 55. Bevel, 56. Wheels thrown into and out of, 76. Gems, artificial, 258. Generation, application of steam by, 105. Generators, in Perkins’s engines, 113, note. Geological formations, or deposits, 279. Geology, value of, in investigating mines, 287. Geometry aids the miner, 289. German silver, 226. Germany, Artesian wells in, 275. Gerstner, rail-way by, 318. Gilding, on metals, 216. On por¬ celain, 272. Gilt wire, 217. Ginning cotton, 169. Glands of couplings, 76. Glass, 248. .Materials composing, 248. Metals of, 248, note. Crown, 249. Fritting, 250. Melting, 250. Blowing, 250. Annealing, 251. Broad, 251. Flint, 252. Bottle, 252. Cylin¬ der, 252. Plate, 253. Casting, 263. Polishing plate, 254. Ground with pure flint. 254, Moulding, 254. Pressing, 255. Cutting, 255. Stained, 266. Enamelling, 257. Artificial gems' made of, 258. Devitrification of, 259. Reaumur’s porcelain from, 259. Crystallo ceramie, 260. Thread, 260. Remarks on, 261. Expansion of, 261. Invention of, 261. Glass globes, silvering the inside of, 231. Glass thread, 260. Glass windows, 261. Glazing ware, 267, 270. Globes, glass, silvering the inside of, 231. Gneiss, metalliferousness of, 282, 283. Gobelins, manufactory of tapestry by the, 179. Going part of clocks, 194. Gold, 212. Extraction of, 212. Cupellation of, 213. Parting, 213. Quartation of, 214. Ce¬ mentation of, 214. Alloy in, 214. Working, 215. Beating, 215. Leaf, 216. Party, 216. Gilding metals with, 216. Wire, 217. Thread, 217. Improvements by Stoddart, in gilding with, 217, note. A coloring material for glass, 258. Localities of, 286. Gold-beating, 215. Gold-leaf, 216. Gold-lustre ware, 273. Goldsmiths’ work, 215. Gold-thread, 217. Gold wire, 217. Governors, in steam-engines, 76, 110, 117. In water wheels, 77. In windmills, 99. Grading rail-ways, 24. Graduated semicircle, used by miners, 289. Granite, combustible fossils not found in, 288. Granite blocks, rail-roads on, 319, 323. Gravity, an obstacle to locomotion, 384 INDEX. 9, 11. Water and wind, appli¬ cations of the force of, 85. Great Dutch canal, in Holland, 36, 802. Great Western steam-ship. Lieu¬ tenant Hosken, commander of the, 44, note. Size of the, 45. Great wheel of a watch, 203. Greek coins, experiments on, by Dize, 226, note. Gregory, Dr., on obviating friction, 15. Grinding of cutlery, 246. Gripes, in nail-machines, 239. Grubbing rail-ways, 331. Guanaxuato, depth of a mine in, 298. Guard-gut of a watch, 202. Gudgeons, meaning of, 195, note. Gun-making, 239. Gun-metal, 225. Gunpowder, substitution of steam for, 129. Manufacture of, 130. Detonation of, 130. Force of, 131. Filing, 133. Blasting with, 134. Value and use of, in mining, 291, 296. Augmenta¬ tion of the effect of, 293. Saw¬ dust with, 293. Guns, steam, 129. Properties of, 132. H. Hair-springs of watches, 193, 204, 206. Halsers, 166. Hammers, tilt, used in iron-works, 236. Hands of clocks, 196. Hardening steel, 242. Hargreaves, James, invention of the spinning-jenny by, 168. Haerlem rail-way, 321, 334. Harness of a loom, 175. Harnessing of horses, 14, 18, 84. Hartz, depth of the shaft in the, 298. Hatchet experiments with alloys, 215, note. Hats, manufacture of, 182. Hawk’s-bill in clocks, 198. Heart-wheels, 64. Heat, effect of, on pendulums,!92; on glass, 261. Arts of indura¬ tion by, 262. Heathcoat’s lace-machine, 178. Heaved veins, 285. Heddles of a loom, 175. Hemp, ropes made of, 166. Spin¬ ning, 167. Machines for spin¬ ning, 167. Paper made of, 183. Herculaneum, glass found at, 261. See Pompeii. Hero’s fountain, 140, 159. High-pressure engines, nature of, 105. Of Evans and Woolf, 106. Form of, 114. Operation of, 114. Steam-power applied to, 127. High-tempferatures, use of steam at, 126. Highs, Thomas, 168, note. Highways, 19. Holland, canals in, 86, 302. Hollidaysburg canal, 315, 330. Railway from, to Johnstown, 332, 334. Home, Sir Everard, on the loco¬ motion of serpents, 11. Hooke’s universal joint, 57. Horizontal, wheels, 95. Wind¬ mills, 100. Scapements of time¬ keepers, 193. Hornblower, application of expan¬ sive steam by, 120. Horology, arts of, 187. Horses, on attaching, to wheels, 14, 18, 84. The power of, 84; compared with man’s, 84. Force and speed of, 84. The drawing of, in circles, 85 ; on revolving platforms, 85. On American rail-ways, 328. Hosken, Lieutenant, commander of the Great Western steam¬ ship, quotation from Redfield’s letter to, 44, note. Hot blast,in smelting furnaces,233. Hot-pressed paper, 184. Hour-hands of clocks, 196. Hour-wheel of watches, 206. Household pumps, 148. Howth, diving-bell used at, 46 INDEX. as 5 Hubs of wheels, 16. Hudson, dam across the, 309. Human power, 82, 84. Buchan¬ an on, 83. On estimating the different applications of, 83. Hungarian machines, 157. Hydraulic rams, 160. Hydreole, 144. Hydrostatic press, 151. I. Inclination of a mineral plane, 280. Inclined plane wheels, 55, note. Inclined planes, canal boats moved by means of, 35, 311. Inclined planes and stationary en¬ gines on rail-roads, 328, 332. Machinery for working, 333. Inclined shafts, in mining, 297. Inclined wheels, 69. Indian steel,experiments with, 241. Indications of metallic mines, gen¬ eral observations on the 285. Negative and positive, 288. See Lodes, Mines, Ores, and Veins. Induration by heat, 262. Inertia, an obstacle to locomotion, 11 . Inland navigation of the United States, 299. Instruments used in subterranean operations, 289. See Subterra¬ nean. Interlaced masses, 283, 285. Inventions, elementary, for the cotton manufacture, 168. Iron, gilding on, 217. Plating on, 222. Articles of, tinned, 229, 230. Valuable properties of, 231. Extraction of, 232. Smelt¬ ing, 232. Crude, 233. Cast¬ ing, 233. Malleable, 235. For¬ ging, 235. Rolling, 237. Slit¬ ting, 237,238. Wire-drawing, 238. Nail-making from, 239. Gun-making, 239. Used for coloring glass, 258. Places for finding, 286. Ore, in America, 324. Iron-hat, 289. Iron pipes, 137. Iron rails, introduction of, 318. In America, 324. Italy, Artesian wells in, 275. J. Jamaica and Brooklyn rail-way, 322,334. Cost of rails and chairs for, 324. Sleepers on the, 324. Jenny, spinning, 168. Jessop’s pistons, 122. Jewelling watches, 207. Jews, sun-dials among the, 187. Johnstown, rail-way to, 332, 334. Joint, the universal, 57. The tog¬ gle, 74. Juniata rail-way, 325. Plan pro¬ posed for the superstructure of the, 326. K. Keel of a ship, 38. Kidderminster carpets, 177, 178. Kilns, for burning bricks, 264. For burning pottery, 269. Kingstown rail-way, 319. Cost of the, 326. Kitspiihl mine, depth of, 298 Knee, or toggle, joint, 74. Knives, 244, 245. Kyan’s anti-dry-rot preparation, 324. L. Lace-machines, Heathcoat’s, 178 ! Laces, 178. ; Lachine canal, 301. i La Garousse, lever of, 74. i’ Lambert’s wheels, 94. ! Languedoc canal, 37, 301. j Lanterns to pinions, 54, 56. : Lap, cotton in, 170. Lardner, on the power of the steam engine, 124. Lay of a loom, 175. Lead, pipes of, 137, and 137, note, 227. Mineralized by sulphur, 226. Extraction of, 226. Man¬ ufacture of, 227. Sheet, 227. Shot, 228. Places for finding, 286. Leaf, gold, 216. 33 xii. 386 INDEX. Leather, used about pumps, 153. Leaves, of pinions, 54. In lied- dles, 175. Leevray of a ship, 41. Lenticular masses, 280. Leslie, on the force and speed of horses, 84. Lever, the universal, 74. Of La Garousse, 74. Lifting pumps, 152. Lighthouses, American, 299. Line, of traction, or draught, 14, 18, 84. Of centres, 54. Linen rag3,^paper made of, 183. Linens, 180. Machines for spin¬ ning, 180. Manufactured by the Egyptians, 181. Live pulleys, 76. Liverpool and Manchester rail¬ way, locomotives on the, 30, 318. Crossing of Chat Moss by the, 323. Cost of the, 325. An¬ nual expenses of the, 327. Localities of ores, see Ores. Locks, canal, 34, 303, 308. Sub¬ stitute for, 35. Locomotion, aids to, 12. Locomotive engines, use of, on rail-roads, 29, 318. Historical facts respecting, 30. Premium for, 30. Weight and power of, 30.- Improvements in, 31. In¬ ternal eonstruction of, 123. Op¬ eration of, 124. liOdes, 280. Origin of, 281. The gangues in, 282, 285. Of four species, 283. The rake-vein, 283. The pipe-vein, 283, 284. Flat, or dilated, vein, 283, 284. The interlaced mass, 283, 285. Accumulated vein, 284. Faults, or shifts, in, 285. See Mines and Veins. London, first paved, 20, note. Ar¬ tesian wells in, 275. Longitudinal galleries, 295, 297. Looking-glasses, silvering of, 230. Looms, 169, 176. Low-pressure engines, boilers in, 108, 109. Construction of, 115. Low temperature, use of vapors of, 127. Fluids boiling at, 127. Lowell rail-road, 319, 334. Lucas, conversion by, of tools of cast-iron into good steel, 246. Lustre-ware, 272. Gold and sil¬ ver, 273. Lying heaps, 280. Lyons, rail-way near, 318. Lysicrates, choragic monument of, 265. M. McAdam roads, 20. Machinery, elements of, 50. Ro tary, or circular motion in, 51. Distant rotary motion in, 59. Change of velocity in, 60. Al¬ ternate or reciprocating motion in, 62. Parallel motion in, 65. Rack and segment in, 70. Rack and pinion, 70. Belt and seg¬ ment in, 71. Scapements in, 71. Continued rectilinear mo¬ tion in, 73. On engaging and disengaging, 75. Equalizing mo¬ tion in, 76. Friction in, 79. .Moving forces of, 81. See Mov¬ ing Forces. Machines, 50. Remarks on sim¬ ple and complex, 80. Zurich, 146. The Hungarian, 1'57. At¬ mospheric, 159. For spinning linen, 180. For manufacturing paper, 184. For coining, 220. See Machinery. M’Taggart, canal by, 305. Magic porcelain, 273. Magnetic compass, used in subter¬ ranean operations, 289; the dial of it, 289. Magnetic engines, 134. Magnetic iron-ore, 286. Maintaining power of time-pieces, 190. Malleability of metals, 235, 236. Malleable iron, 235. Man, power of, to produce motion, 82. See Human. Manchester rail-way, see Liver¬ pool. Manganese, used for coloring glass, 258. INDEX. 387 Mangles, 71. Man-holes for steam-engines, 110. Maple sugar, manufacture of, 337. Marseilles quilts, 177. Masses of mineral deposits, 280. The interlaced, 283, 285. Matrix of a metal, 209. Medals, coining, 220. Of gun- metal, 226, note. Copying, 349. Melting the frit of glass, 250. Melting-pots, materials for, 265. Menai bridge, 23, 125. Mercurial, or disengaging, process, in photogenic drawing, 358. Mercury, used in silvering, 230, 231. Places for finding, 287. See Quicksilver. Metallic baths, Parkes’s, 244. Metallic deposits, negative and positive indications of, 288. Metallic mines, general observa¬ tions on the indications of, 285. See Clines and Ores. Metallic oxides, 249, 256. Metallurgy, arts of, 208. Metals, extraction of, 209. Na¬ tive state of, 209. Mineralized, or in the state of ore, 209. Oangue, or matrix, of, 209. Sor¬ ting, 209. Stamping, 209. Washing, 209. Roasting, 210. Smelting, 210. Reducing, 210. j Refining, 210. Assaying, 210. j Alloys in, 211. Gilding on, 216. Annealing, 216, note. ; Coining, 219. Plating on, 220. Gun, bell, and speculum, 225, 226. Moulds for casting, 233. | Meaning of the word, as ap- ; plied to glass, 248, note, 230. Employed as coloring materials for glass, 238. See Ores. Mexico, depth of a mine in, 298. Mica-slate, 282. Milling coins, 219. Mills, drawing in, by horses, 85. BarkeV’s, or Parent’s, 96. Wind, 97. Post, 99. Hori¬ zontal wind, 100. Fulling, 181. Mineral veins, see Lodes and \ eins. Mineralized metals, 209. Mineralizer, 209, Miners, distinction of mineral veins by, 283. Aided by geology, 287. Cleans of, for penetrating into the interior of the earth,290. Shovels of, 290. See Mines. Mines, copper, 222, 286. Ure’s Dictionary on, 279. Indications of metallic, 285. Geology a guide in the investigation of, 287—289. Instruments em¬ ployed in, 289. Tools used in, 290. Value and use of gun¬ powder in, 291. Use made of fire in, 294. Depth of several, ’ 297, 298. See Earth, Excava¬ tion, Lodes, Miners, Ores, and Veins. Mint in England, 220. j Minute-hands of clocks, 196. Minute-wheels of watches, 205. Mirrors, silvering of, 230. Mixed pumps, 151. Money, coinage of, 219. Montgolfien invented balloons, 48. Monument of Lysicrates, 265. Moody, Paul, 174, and 174, note. Moreys’ engines, 123, 128. Morris canal, 311, 315. Motion, 51. Rotary, or circular, 51. Distant rotary, 59. Change of velocity in, 60. Alternate, or reciprocating, 62. Parallel, 65. Continued rectilinear, 73. Change of direction in, 74. On equalizing, 76. Rotary, in Bar¬ ker’s mill, 96. Parallel, intro- I duced into steam-engines, 122. : Motion of animals, 9, 10. Moulding glass, 254. ' Moulds, paper, 184. For casting metals, 233. For glass, 254, 255. For casting pottery, 269. Saggars, 269. .Movement, the regulating, of time¬ pieces, 191. Moving forces used in the arts, 81; Mudge on speculum-metal, 226. Mules, 169. Mule-spinning, 173. Mummies, glass found with, 261. 388 INDEX. Murray’s engine, 116, 123. Muscular power, 82. Of men, 82. Of horses, 84. Muskets, manufacture of, 239. N. Nail, a rod used by miners, 291. Nail-making, 239. Nap of broadcloths, 182. Napoleon, reward offered by, 180. National road, 331. Native state of metals, 209. Natural steel, 241. Naves of wheels, 16, note. Navigation, steam, 42, 45. Sub¬ marine, 47. Inland, in Ameri¬ ca, 299, 314. Slack-water, 306, 314. Needles, polishing, 246. Negative indications of metallic deposits, 288. Nests, in geology, 280. Newcastle rail-way, 320, 335. Newcomen’s atmospheric engine, 115, 120. New Orleans, see New York. Newsham’s fire-engines, 163. New York, route and distances from, to New Orleans, 300. New York canal, see Erie. New York rail-way, see Ilaerlem and Paterson. Niagara and Buffalo rail-way, 321, 834. Nickel, localities of, 287. Nodules, in geology, 280. Noa-condensing engines, see High- pressure engines. Noria, 143. Norristown rail-road, 321. O. Oars, propulsion of boats by, 42. Obstruction of pipes, 139. Off-cast veins, direction of, 285. Ohio rail-road, 325, 335. Open trench, working by, in min¬ ing, 296. Open workings, in mining, 296. Ores, 209. Locality of, 282, 285. Value of geology fbr finding, 287. See Mines. Overflowing wells, see Artesian. Overshot-wheels, 85. Pressure of the atmosphere on, 88. Most advantageous velocity of, 90. Oxides, metallic, 249, 256. P Pacos, 289. Paddles, propulsion of boats by, 42, 43. Paddle-wheels, 42. Painted glass, 257. See Stained Pakfong, Chinese, 226. Pallets, of scapements, 72. In clocks, 196. Gathering, of a clock, 198, 199, Palmer, rail-way of, 27. On dust on rail-ways, 29. Pantheon, Rotunda of the, brick, 262. Paper, materials for, 183. Man¬ ufacture of, 183. Sized, 184. Blotting, 184. Hot-pressed, 184. Machines for manufactur¬ ing, 184. Rapidity of manufac¬ turing, 185. Preparation of, for photographic drawing, 365. Parachutes, 49. Parallel motion, 65, 122. Parent’s mill, 96. Paris, first paved, 20, note. Parkes, metallic baths of, 244. On supplying the Ch'uiese with cobalt, 270, note. Parting gold, 213. Party-gold, 216. . Pascal, hydrostatic press by, 151. Passenger-boats, see Boats. Passenger-cars, 329. Passey, paper in the possession of, 185. Passings, in rail-ways, 28. Paste gems, 258. Paternoster-work, 157. Paterson rail-way, 320, 334. Patterns, for castings, 233. Pavements, 19. Wooden, 20. In ancient cities, 20, note. Tel¬ ford’s, 20, 7iote. Peace, Temple of, 262. Pearl buttons, brass eyes of, 224. Pearson, on gun-metal, 226, 7iote. INDEX. 389 Pebbles, use of, in pavements, 20. Pendulums of clocks, 191, 195. Remedies for the effect of heat on, 192. See Hair-springs. Penknives, 244, 245. Pennsylvania canal, 315, 328, 330, 331. Pennsylvania State canals, travel¬ ling on the, 306. Perkins, propelling wheel of, 43. On getting rid of back-water, 92. Generators in the engines of, 113, 7ioie. Steam-gun by, 129. Inventions by, 129, note. Perpendicular pits, 297. Perpetual screws, 57. Persia, ancient bricks in, 262. Persian wheels, 143. Peterhoff, fountains at, 162. Phials, Bologna, 251. Philadelphia rail-way, see Colum¬ bia and Norristown. Photogenic drawing, 350. Prepar¬ ing the plate for, 351. Coating the plate for, 353. Use of the camera obscura in, 356. Sea¬ sons for, 357. Mercurial, or dis¬ engaging, ]»roccss in, 358. Fix¬ ing the impression in, 360. Talbot’s experiments in, 362. Ponton’s method of preparing paper for, 365. Photography, 350. See Photo¬ genic drawing. Pick,' used by miners, 290, 296. Picker, cotton, 169. Piercers, of cartridges, 292. Piers, of bridges, 22. | Pig-iron, 233. Piles, in rail-roads, 322, 323. Pinchbeck, 224. Pinion, 53. Leaves of,. 54. Lan¬ terns to, 54, 56. Rack and, 70. In watches, 205. Cannon, 206. Pins, 225. Pipe clay, 267. Pipe-veins, 283, 284. Pipes, steam, 117. F.duction, 118. Water, 136. Wooden, 137. Iron, 137. Copper, 137. Lead, 137,227. Stone, 138. Earthen, 138. Friction of, 138. Qnan- 33* tity of water conveyed in, 138, 139. Velocity of water in, 138. Size and form of, 138, 139. Curves in, to be avoided, 139, 140. Obstruction of, 139. Arrangement of, 156. Pistons, of steam-engines, 117, 118, 122, 123. For pumps, 151, 152. Pitch lines, 54. Pits, perpendicular, 297. Pivots, meaning of, 195, note. Planchets in coining, 219. Planet wheels, 67. Plate glass, 253. Plated baskets, 222. Plates, tin, 229, 230, 237. Plating with silver, 220, 222. Plunger pumps, 149. F’lying cotton, 170, 171. Pointerolle, 290. Polishing, silver, 219. Cutlery, 246. Plate glass, 254. Poll of a pick, 290. Pompeii, pavements in, 20, note. Glass found at, 261. Pompey introduces the clepsydra into the Senate House, 188. Ponton, Mungo, 365. Porcelain, Reaumur’s, 259. In¬ gredients of, 265. Manufacture of, 266. Drawings on, 270. Chi nose, 271. European, 271. Earths, in the United States, 272. Gilding, 272. IMagic, 273. Portage, see Alleghany. Portland vase, 273. Imitated,273. Positive indications of metallic de¬ posits, 288. Post-mills, 99. Potence, in a watch, 203. Pottance, in a watch, 200, 203. Pottery, 265. Operations in, 266 Glazing, 267, 270. Throwing, 268. Pressing, 269. Casting, 269. Burning, 269. Printing, 270. See Porcelain. Pottsville rail-road, 325, 335. Powder, see Gunpowder. Power, sources of, 81. Vehicles I of, 81. Animal, 82. Water, I 85. Wind, 97. Steam, 100 390 INDEX. Of the steam-engine, 124. Of gunpowder, 130. The main¬ taining, of time-pieces, 190. Power-looms, 169, 176. Powers acting witliin a boat, 42. Precious stones, in watches, 207. Press, hydrostatic, 151. Pressed bricks, 263. Pressing of glass, 255. Of pottery, 269. Primary rocks, 279. Primitive, radius, 54. Circum¬ ferences, 54. Prince’s metal, 224. Printing ware, 270. Projecting water, 161. Prongs of forks, 245. Propelling power, on rail-ways, 29. Propelling wheel of Perkins, 43. Proportional radius, 54, 7iote. Providence rail-way, 321, 334. Proximate positive indications of metallic deposits, 288. Puddle for lining canals, 33. Puddling-furnaces, 235. Pulleys, 76. Pulp for paper, 184, 185. Pumps, in steam-engines, 118. Rope, 143. Spiral, 145. Cen¬ trifugal, 146 Common, 147. Household, or sucking, 148. Forcing, 149. Plunger, 149. De la Hire’s, 151. Mixed, 151. Lifting, 152. Bag, 153. Dou¬ ble-acting, 153. Rolling, 154. Eccentric, 155. Chain, 157. Bead,157. Cellular, 157. Punt, or punting-iron, 251, note. Puppet valves, 121. Pyramids, 125, 263, note. Q. Quadrupeds, locomotion of, 10. Swimming of, 11. Quartation of gold, 214. Quarter, wind upon the, 39. Quicksilver, alloys of, 211. Ex¬ traction of gold by amalgama¬ tion with, 212. See Mercury. Quilts, Marseilles, 177. Quincy rail-way, 318, 334. R Rack, and segment, 70. And pin¬ ion, 70. Of a wheel in clocks, 198, 199. Racks, 73. Radius, 54, and 54, note. Rag wheels, 52. Rags for making paper, 183. Rails, materials of, 25. Weight of, 27. Introduction of cast- iron, 318 ; of malleable iron, 318. In the United States, 324. Rail-ways, object of, 24. Modern, 24. Compared with turnpikes, and canals, 24. On the con¬ struction of, 24, 323. The dif¬ ferent varieties of, 25. Pas¬ sings, or sidings, in, 28. Turn- plates in, 28. Curves in, 28. Crossing public roads, 29. Dirt on, 29. Propelling power on, 29. Locomotives for, 29. Sta¬ tionary engines, and inclined planes on, 31, 328, 332. Am¬ erican, 298, 299, 318, 334. Foreign, 318. The sleepers in, 324. Cost of American, 325, 326 ; of English, 32.5 Annual expenses of, 327, 329 Horses on, 328. Fuel, 328. Grubbing, 331. Machinery for working inclined planes on, 333. Tables of, in the United States, 334—336. Raising water, 142. See Water. Rake-veins, 283. Rams, hydraulic, 169. Rasping beets for sugar, 341. Ratchet wheels, 58. Razors, 244, 245. Reaumur, porcelain of, 259. On glass thread, 260. Receivers, in pressing glass, 255. Reciprocating motion, 62. Rectilinear motion, continued, 73. Redfield, W. S., 44, note. Reduction of metals, 210. Refining metal, 210. Regulating movement of time¬ pieces, 191. Regulator of a watch, 193 INDEX. 391 Remote positive indications of me¬ tallic deposits, 288. Rents, in geological strata, 281. Reservoirs for beet juice, 342. Retarding wheels, 31. Rideau canal, 305, 307. Roads, hints on, 19. McAdam, 20. Loss of power on, 24. The National, 331. Roasting ores, 210. Robinson, Moncurc, on the cost of rail-ways, 325. Cited, 326. Robison, John, on the overshot wheel, 86. On the escape of air and water through a hole, 88. Describes a machine, 89. Rocket engines, 30. Rocks, 134. See Blasting. Rollers, 13. Rolling and slitting iron, 237. Rolling pumps, 154. Roman coins, 226, note. Romans, aqueducts among the, 136. Windows among the, 261. Rome, paved, 20, note. The first sun-dial at, 188. The clepsy¬ dra brought to, 188, note. Ancient bricks at, 262. Roofs, covered with tiles, 264. Rope-pumps, 143. Ropes, 165. Rotary,or circular,motion,51. Dis¬ tant, 59. In Barker’s mill, 96. Rotary valves, 121. Rotative engines, 126. Rotunda of the Pantheon, 262. Rouge d’ Angleterre, 246. Routes of canals and rail-roads in North America, 300, 314, 334. Roving-frames, 170, 171. Sim¬ pler form of, 172. Rowntree’s engines, 163. Roy, on e.vpansion of glass, 261. Rubies, in watches, 207. Rudder of a ship, 38. Rupert’s drops, 251. Russel, on the velocity of wave in canals, 302. Russia, founta'ms in, 162. S. ' Safety-gates in canals, 34. Safety-valves, 112. Saggars, 269. Sailing, 37. Before the wind, 39. Large, 39. Sails of windmills, 97. Angle for, 98. Adjustment of, 98. St. Austle, steam-engine at, 125. Sampson mine, shaft at the, 298. Sand,for moulds,233. Ingla8s,248. Sankey Brook canal, 301. Santee canal, 301, 317. Saratoga and Schenectady rail way, 320, 334. Cost of the,325. Sarcophagi, glass found on, 261. Savannah, steam-ship, 44. Sawdust, with gunpowder, 293. Saws, 244, 245. Saxony, the porcelain of, 272. Scapements, 71. Pallets of, 72. Crutch, 72. Watch, 72. Of time-pieces, 193, 200, 204. Scape-wheels, 193, 204. Schemnitz vessels, 157. Schenectady, see Albany, Sarato ga, and Utica. Schists, gold found in, 286. Schuylkill, bridge, 22. Slackwatei navigation, 306, 316. Scissors, 244, 245. Scoop wheels, 142. Scoria, 232. Scotland, canal in, 36. Screws, propulsion of boats by, 42 Perpetual, or endless, 57. De¬ finition of, 74. Archimedes’ 144. The water, 145. Scudding before the wind, 39. Secondary rocks, 279. Segment,rack and,70. Beltand,7I. Semicircle, used by miners, 289. Separating metal, 209. Serpents, locomotion of, 11. Setting the edges of cutlery, 246. Severus, Alexander, Portland vase discovered in the tomb of, 273. Sevres, porcelain made at, 271. Sewing-thread spun by mules,174. Shafts, to ventilate canal tunnels, 33. Means of, 195, note. In mining, 295. Depths of, 297. Shanks of brass buttons, 224. Shearing cloths, 182. 392 INDEX. Shear-steel, 241. Sheet lead, 227. Sheldrake, T., inclined plane wheels by, 55, note. Shifts, in mineral veins, 285. Ships, form of, 37. Bows of, 38. Keels and rudders of, 38. Ef¬ fects of wind on, 39. Stability . of, 41. Crank, 41. ToostifF,41. Shooting tools of miners, 290. Shot, manufacture of leaden, 228. Shovels, miners,’ 290. Shrouds, 166. Shuttles, 175. Sidings, in rail-ways, 28. ^lesia, use of sawdust in, 293. Silver, extraction of, 217. Eliqua- tion of, 218. Working, 218. Solder used for, 219. Polishing, 219. Alloyed, 219. Coining, 219. Milling, 219. Plating with, 220, 222. Edges, 221. Ger¬ man, 226. Use of, for coloring glass, 258. Localities of, 286. Silvering of mirrors,230. Of look¬ ing glasses, 230. Of glass globes, 231. Silver-lustre ware, 273. Silversmiths’ work, 218. Simplon and Mount Cenis, 298. Singing cotton fabrics, 180. Single rail-ways, 27. Size, of wheels, 13. Of canals, 36. Sizing paper, 184. Slackwater navigation, 306, 307. In canals, 307, 314, 330. Slag, 232. Sleepers, used on rail-roads, 324. Sliding valves, 121. Slip, used in pottery, 269. Slitting iron, 237, 238. Sliver, cotton in, 170. Slubbing machine, 181. Smeaton, on muscular power, 84. On the velocity of wheels, 90, 91. On float-boards, 91. Smelting, metal, 210. Iron, 232. Smifts, used in blasting, 290, 291. Snails, water, 144. In clocks, 198. Snifting-valves, 118. Solder, for silver, 219. In pla¬ ting copper, 221. Sorting metal, 209. Sources of power, 81. See Power Sparry iron-ore, 241. Speculum-metal, 225, 226, 230. Speed, of steam-boats, 44, and 44, note. See Velocity. Spencer, on voltaic electrical en¬ graving, 348—350. Spindle-rails, 171. Spinning, mechanism of simple, 165, 168. Hemp, 167. Cotton, 172. Mule, 173. Glass, 260. Spinning-frames, 168, 173. Spinning-jenny, 168. Spiral gear, 55, and 55, note. Spiral pumps, 145. Spiral wheels and water-screws, propulsion of boats by, 42. Spoon, of the Zurich machine, 146. Spouting wells, see Artesian wells. Springs, of carriages, 17. Of watches, 190,191,200,201,204. Spur-gearing, 53. Stability of a ship, 41. Staffordshire, mine in, 298. Stained glass, 256, 258. Stamping metal, 209. Started veins, 285. State w'orks, 300. Stationary engines. See Inclined. Steam, propulsion of vessels by, 42. Expansion of water, when converted into, 100. Atmos¬ pheric weight upon, 101, 102, Increase of, after separation from water, 101. Three meth¬ ods of obtaining power from, 103. Application of, to engines, 114. Use of, at high tempera¬ tures, 126 ; at low tempera¬ tures, 127. Substitution of, for gunpowder, 129. Steam-boats, 42. Speed of, 44. Steam-carriages, 129. Steam-engines, 42. Cartwright’s, 67, 122. Governors in, 76,110, 117. Estimation of the power of, by horses’ power, 84. Ear¬ liest attempts at forming, 103. Remarks on, 107. Boilers in, 108. Appendages to, 110 Brathwaite and Ericsson’s, 113 INDEX. 393 Application of steam to, 114. Newcomen’s atmospheric, 115, 120. Description of the double- acting, 116. Expansion, 119. Condensers in, 120. Valves of, 121. Pistons, 122. Parallel motion in, 122. Estimates on the power of, 124. At St. Austle, in Cornwall, 125. Pro¬ jected improvements in, 126. Rotative, 126. See High-pres¬ sure, Inclined planes, Locomo¬ tive, and Low-pressure. Steam-guages, 110. Steam-guns, 129. Steam-navigation, 42, 45. Steam-pipes, 117. Steam-power, 100. Steam-ships, the Atlantic first cros¬ sed by, 44. The Great Wes¬ tern, 44, note, 45. The Brit¬ ish (iueen, 45. Steel, gilding on, 217. Hardness and tenacity of, 232. Iron re¬ combined with carbon, 240. The iron used in, 240, 241. Ce¬ mentation of, 240. Blistered, 240. Tilted, 240. Shear, 241. Cast, 241. Natural, 241. Al¬ loys of, 241. Stodart’s and Faraday’s experiments on, 241. Indian, 241. (Quantity of car¬ bon in, 241, note. Case-har¬ dening, 242. Tempering, 242. Cutlery, 245. Conversion of cast-iron into, 246. Steps, in mining galleries, 296. Stevenson, G., rocket-engine by, 30. On canals in North Ameri¬ ca, 298. On rail-ways, 318. Stodart, on steel, 241. Stoddart, on gilding, 217, note. Stone, bridges, 22. Pipes, 138. Stones, factitious, employed by the ancients, 263. Rail-ways laid on, 319, 321, 323. Stoiie-ware, manufacture of, 267. Stop-gates, in canals, 34. Stourbridge clay, crucibles of, 265. Strainers, for water pipes, 139. Strand of n rope, 166. Stratiform deposits, 279. Strength of man, 84, 150. Stretching, the process of, 173. Strikes, used in manufacturing sheet-lead, 227. Striking part of a clock, 194, 197. Submarine navigation, 47. Subterranean operations, instru¬ ments for, 289. Workings, in mining, 296, 297. See Mines. Sucking-pumps, 148. Sugar, maple, 337. See Beet. Sulphate of soda may be employed in glass-making, 249. Sulphur, lead mineralized by, 226. Sun and planet wheels, 67. Sun-dials, 187. Superstructure for rail-roads, 326. Supporters of rail-ways, 319, 323. Suspension bridges, 23. Swab-sticks of borers, 290. Sweden, copper mines in, 222. Swimming, of fishes, 10. Of laud animals, 11. Of birds, 11. Swimming bladders, 11, note. Switch, in rail-roads, 28. Swords, tempering of, 244, note. Syphons, 141. T. Table, of canals in the United States, 314 ; of rail-ways, 334. Table-forks, 244, 245. Prongs of, 245. Table-knives, 244, 245. Tail-water, remedies for, 92, 93. Talbot, experiments by, 362. Tamping, by miners, 291. Tamping-bars, 291. Tapestry, 179. Taunton spindle, see Danforth’s. Taylor, on depths of mines, 297. Teazles, 182. Teeth of wheels, 53. The cut of, 55, 56. Telescopes, speculum-metal used in, 225, 226, 230. Telford, paved road by, 20, riote. Temperatures, use of steam at high, 126; of vapors of low,127. Tempering steel, 242. By metallio 394 INDEX. baths, 244. By Ferrara, 244, note. Temple of Peace, 262. Tenders, see Locomotive. Terra-cotta, 264. Terre-cuite, 264. Test-bars, 240. Thames, bridges across the, 22. Thenard, on steel, 242. Theory of twisting flexible fibres, 164. Thermae, of brick, 262. Third wheel of a watch, 203. Thread, gold, 217. Glass, 260. Throttle-valves, 121. Throwing, in pottery, 268. Throwing-wheels, 163. Tides, velocity of, 44, note. Tightening wheels, 76. Tiles, 264. Tilt-hammers, 236. Tilted-steel, 240. Timepieces, 189. Essential parts of, 190. Maintaining power of, 190. Regulating movement of, 191. Pendulums of, 191. Bal¬ ances of, 192. Scapemeuts of, 193, 200, 204. See Clocks and Watches. Tin, in bronze, 225. Extraction of, 229. Block, 229. Foil, 229. Plates, 229, 237. Silvering with, 230, 231. Localities of, 285. Tin-foil, 229. Tinning, copper, 223. Plates, 229, 230. Tinstone, 229. Toggle joint, 74. Tombac, 224. Toothed wheels, 53. Torpedo, Fulton’s, 48. Tower of the Winds, 188. Traction, line of, 14, 18, 84. Train of a watch, 202. Tram-roads, 27, 318. Transition rocks, 279, 283. Transits on rail-ways, 328. Transverse galleries, 295, 297. Trautwine, sections of rail by, 26. Travelling, on canals, 306. Treadwell, on using steam, 113. Condensers by, 121. Machines by, for spinning hemp, 167. Tredgold, 24, 43. Trench, working by an open, in mining, 296. True radii, 54. Trundles, in machinery, 54. Tub-wheels, 95. Tunnels, for rail-roads, 25. For canals, 33. At Worsley, 34. Turkey carpets, 179. Turnpikes and rail-roads, 24 Turn-plates, on rail-ways, 28 Turn-tables, on rail-ways, 28. Tweeled-cloth, 176. Twilled fabrics, 176. Twilling, 176. Twisting, theory of, 164. U. Undershot wheels, 85, 90. Ve¬ locity of, 91. Size of, 91. Float-boards of, 91. Universal, joint, 57. Lever, 74. Utica and Schenectady rail-road, 327, 334. V. Valenciana mine, depth of, 298. Valves, in canal-gates, 35. Of steam-engines, 112, 117, 118. Different kinds of, 121. Vapors of low temperature, 127. Vases, 273. Vehicles of power, 81. Veins, 282. Rake, 283. Pipe, 283,284. Flat, or dilated, 283, 284. The interlaced mass, 283, 285. Shifts, or faults, in, 285. Direction of offcast, 285. Heaved, 285. Started, 285. Exploring, 296. See Lodes and Mines. Velocity, change of, in machinery, 60. Of overshot-wheels, 90. Of undershot-wheels, 91. Of water in pipes, 138. In cotton machines, 170. Velvets, 179. Venetian carpets, 178. Ventilation of tunnels, 33. INDEX. 395 Verge of a balance-wheel, 203, 207. Vertical windmills, 97. Vessels, Schemnitz, 157. Viaducts, 25, 332. Vitrification, arts of, 247. Voltaic electrical engraving, 348. W. Wagons, 12. Retarding, 31, note. Wales, bridge in, 23, 125. Walking, 10. Ware, Biddery, 229. Wedge- wood’s, 265, 267. Earthen, 265, 266. Common crockery, 265. Glazing, 267, 270. Stone, 267. White, 267. Throw¬ ing, 268. Pressing, 269. Cast¬ ing, 269. Burning, 269. Print¬ ing, 270. China, 271. See Porcelain. Warning-piece, in clocks, 198. Warp, 175. Warping cotton, 174. Warping-machines, Moody’s, 174. Washing metal, 209. Washington, see Baltimore. Watch scapements, 72. Watches, fusees of, 62, 191, 200 —202. Essential parts of, 190. Maintaining power of, 190. Springs of, 190, 191, 200, 201 —204. Chains of, 190, 191, 200,201. Barrels in, 191, 195, 197, 200, 201. Regulating movement of, 191, 206. Bal¬ ances of, 191, 192, 203. Hair¬ springs of, 198, 204, 206. Reg¬ ulators of, 193. Scapements of, 193, 200. Description of, 200. Wheel-work of, 200, 203. Guard-gut of, 202. Train of, 202. Minute wheel in, 205. Hour-wheel of, 206. Cannon- pinion in, 206. Curb in, 206. Addition of jewels to, 207. Number of pieces in, 208. Number of trades employed in, 208. Water, movement of bodies through, 37. Dead, 37. Va¬ riations in the fall of, 88. Great¬ est effect of the action of, on machinery, 91. Delivering, on an undershot-wheel, 92, 94. Back, or tail, 92. On breast- wheels, 94. On horizontal or tub-wheels, 95. In Barker’s, or Parent’s, mills, 96. Expan¬ sion of, when converted into steam, 100. For boilers of steam-engines, 108. Arts of conveying, 135. Subterranean passages for, 136. Pipes for transmitting, 136. Velocity of, in pipes, 138. Obstruction of, in pipes, 139. Conveyed in sy¬ phons, 141. Raising, 142 ; by the scoop-wheel, 142 ; by the Persian wheel, 143 ; by the noria, 143 ; by the rope-pump, 143 ; by hydreole, 144 ; by Archimedes’ screw, 144 ; by the spiral pump, 145 ; by the centrifugal pump, 146 ; by common pumps, 147 ; by the forcing pump, 149 ; by the plunger pump, 149 ; by De La Hire’s pump, 151 ; by the hy¬ drostatic press, 151 ; by the lifting pump, 152 ; by the bag- pump, 153 ; by the double-act¬ ing pump, 153 ; by the rolling pump, 154 ; by the eccentric pump, 155. Arrangement of pipes for raising, 156. Raising by the chain-pump, 157 ; by Schemnitz vessels, or the Hun¬ garian machine, 157 ; by He¬ ro’s fountain, 159 ; by atmos¬ pheric machines, 159 ; by the hydraulic ram, 160. Project¬ ing, 161 ; by fountains, 161 ; by fire-engines, 162. Lifted and projected by throwing wheels, 163. Rise of, in Arte¬ sian wells, 276. Water-clocks, 189. Water-pipes, 136. See Pipes. Water-power, 85. Water-screws, 42, 145. Water-snails, 144. INDEX. ^9G Water spinning-frame, 168. Water-wheels, governors in, 77, Watt, James, inventor of the sun and planet wheel, 67. On a horse’s power, 84. Form of boilers used by, 107. Conden¬ ser invented by, 116, 120. Double-acting engine of, 116. Parallel motion introduced into engines by, 122. Coining ma¬ chinery by, 220. Weaving, 175. Double, 177. Cross, 177. Wedgewood, ware of, 265, 267. Manufactory of, 267. Imitated the Portland vase, 273. Weft of cloth, 175. Weight, animals draw through the medium of, 15. Of rails for rail-ways, 27. Of locomotives, 30. Weights, raising of, by human power, 84 ; by horse’s power, 84. Of clocks, 190, 195. Weirs, in canals, 34. Wells, Artesian, 275. Wheel-carriages, 12. 'Vheel-work, of a clock, 194. Of a watch, 200, 203. Wheels, mechanical action of, 12. Size of, 13. Attaching horses to, 14, 18,84. Broad, 15. Form of, 16. Cut of, 17. Perkins’s propelling, 43. Band, in ma¬ chinery, 51. Rag, 52. Toothed, 53. Spiral gear, 55. Bevel gear, 56. Crown, or contrate, 66. Universal joint instead of, 57. Perpetual screw, 57. Brush, 58. Ratchet, 68. Change of velocity inj 60. Fusee, 62, 191, 200—202. Eccentric, 63. Cams for, 63. Heart, 64. Cranks in, 65. Sun and planet, 67. In¬ clined, 69. Epicycloidal, 69. Rack and segment, 70. Rack and pinion, 70. Thrown into, and out of, gear, 76. Tightening, 76. Fly, 78. Horses on, 85. Over¬ shot, 85. Breast, 85, 94. Un¬ dershot, 85, 90. Chain, 88. Besant’s, 9k Lambert’s, 94. Horizontal, or tub, 95. Scoop, 142. Persian, 143. Throwing, flash, or fen, 163, Of clocks, 194. Of watches, 200—206. For making ware, 266, 268. White, inventor of the spiral gear, 55, note. White-metal buttons, 224. White ware, manufacture of, 267. Wind, effect of the, on ships, 39. Action of, on wind-mills, 97. Windage, in guns, 132. Windmills, vertical, 77. Hori¬ zontal, 100. Windows, 261. Wind-power, 97. Winds, Tower of the, 188, Wipers, 64. Curves for, 64, note Wire, gilt, or gold, 217. Wire-drawing, 238. Wirtz, Andrew, machine by, 146. Wooden, pavements, 20. Bridges, 21. Pipes, 137. Woof, of cloth, 175. Wool, remarks on, 181. Woolf, engines of, 103, 106, 120. Woolf’s shaft, depth of, 298. Woollens, 181. Wootz, 241. Worcester rail-way, 327, 334. Working, of gold, 215. Of silver, 218. Of copper, 223. Worm, the, 67. Worsley, tunnel at, 34. Worsted, 181. Wrought-iron, 235. Wrought-nails, 239. Y. Young, Dr., spiral pump, used by, 146. On the greatest effect produced by a laborer, 160. Z. Zinc, 223, 287. Zurich machine, 146. END OF VOL. 11. t'if/. GETTY CENTER LIBRARY 3 3125 00742 9406