iiiiii iliiiiiiil THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES GIFT OF John S.Prell MILLS AND MILLWOEK PART II. tOXDOJT PRIXTRD BY SPOTTISWOCDK AND CO. ITEW-STEEET SQACRE TREATISE OK MILLS AND MILLWOEK PART II. ON MACHINEEY OF TR.iNSMISSION AXn THE CONSTRUCTION AND AERANOEMENT OF MILLS COMPHISING THEATISES OX WHEELS, SHAFTS, AND COUPLINGS ; ENGAGING AND DISENGAGING GEAH ; AND STELL ARCHITECTURE ; AND ON CORN, COTTON, FLAX, SILK, AND WOOLLEN MILLS I TO 'WHICH IS ADDED A DESCRIPTION OF OIL, PAPER, AND PO'WDER MILLS, INCLUDING A SHORT ACCOUNT OF THE MANLTACTCRE OF IKON WILLIAM FAIRBAIEN, ESQ., C.E. LL.D. F.E.S. F.G.S, COKBESPONDING MF.MBEB OF THE NATIONAL INSTITUTE OF FRANCE, AND OP THE KOTAL ACADEMY OF TURIN : CHKTALIER OF THE LEGION OF HONOUR: JOHN C Pi^ELL ^'"^^^^^^hanical Engineer LONDON LONGMAN, GREEN, LONGMAN, ROBERTS, & GREEN 1863 Tbe ri'jht of translation is resen-eJ Librarr FiSt V* 2. PREFACE. In the first part of this work I endeavoured to give a succinct account of nearly fifty years experienced in the profession of a mill architect, millwright, and mechanical engineer. JMy professional career commenced just at a time when the manu- facturing industry of the country was recovering from the effects of a long and disastrous war, and I was enabled, from this circumstance, to grow up with and follow out consecutively nearly the whole of the discoveries, improvements, and changes that have since taken place in mechanical science. These discoveries have been numerous and invaluable in contributing to the developement of our industrial resources, the diffusion of knowledge, and the extension of trade and commerce throughout the globe. It mil not be necessary to repeat what steam, gas, and electric telegraphs have effected both on sea and land in the same time, and how much we are indebted to these agencies for the abundant comforts, luxuries, and enjoyments which we now possess, as compared with the age in which our fathers lived. It will be found on enquiry that in mills, where these agencies are employed, and where the manufacture of cotton, silk, flax, and wool are carried on, are some of the elements to which we are indebted for the numerous advantages which enter into the improved state of our social existence. To mills, therefore, I have directed my attention, and in this volume I have endea- voured to follow up more in detail the principles of construction and other serviceable data to which, I trust, the intelligent student may refer with some prospect of advantage. On prime movers as comprised in water-wheels, turbines, VI PREFACE. steam-engines, &c., I must refer the reader to the first part of this work. The present volume is chiefly directed to what is known by the name of mill-gearing; and in Section IV. Chapter I., will be found an elaborate treatise on wheels, ex- hibiting the relations of diameter, pitch, width, and formation of teeth, including formulae for calculating the strength, pro- portions, &c., to be observed in the construction of spur and bevel gear. Also tables of the proportions of wheels, pullies, &c., computed from data founded vipon experiments and tested in actual practice, which in some respects I believe to be more convenient and comprehensive than any hitherto published. In the same Section I have devoted a chapter to the strengths and proportions of shafts, including rules and tables for calculating their resistance to strains produced by pressure, torsion, &c., and these, with the proportions of journals, friction, lubrication, and other conditions, constitute the contents of Chapter II. Chapter III. treats of the couplings of shafts, engaging and disengaging gear, and those connections by which motive power may be conveyed to a considerable distance from the prime mover, and by which all the necessary changes of stop- ping and starting machines may be effected at one part of the mill without detriment or interference wnth the machinery of any other part. The first chapter of Section V. embraces a short treatise on mills and mill architecture, with illustrations, suggestions, and improvements to be employed in the construction of those edifices. I have been induced to refer to this subject from the fact, that in former times anything like architecture as applied to mills was unknown and greatly neglected ; and there was a total disregard of taste or design until late years, when a few examples of architectural construction were afforded by the in- troduction of slight cornices and pilasters, showing that it was possible at a small cost to relieve the monotony of a large brick surface, and bring the structure within the ca- tegory of light and shade. This to some extent introduced a PREFACE. Vn better style of building; and on tliis subject I have given a few examples for the guidance of the millwright and engineer. Chapter II. Section V. treats exclusively of corn mills ; and as these constructions are chiefly in the hands of the millwright, I have been more particular in directing attention to the biuld- ings as well as the machinery. In this department will be found several examples and illustrations of the best constructions, from those with two to others with thirty-six pairs of stones, including all the necessary machinery for cleansing, grinding, dressing, &c. I have also given a description of the floating-mill erected for the Grovemment during the late Crimean war ; and this, with numerous details of elevators, Archimedean screw, creepers, &c., calculated to make the mills self-acting, comprise the treatise on grinding corn. Chapters III. IV. V. and VI. are descriptive of mills for the manufacture of the textile fabrics, as comprised in cotton, woollen, flax, and silk mills. These chapters are directed more to the process of manufacture and less to details than those on corn. They, however, contain illustrations and examples of each kind of manufacture taken from mills of my own construc- tion. They show the arrangement, but are not descriptive of the machinery, as machine making for the separate purposes of manufacture is now a distinct trade, and does not therefore enter into that of the millwright. Having omitted the ma- chinery — which may be found in other works on that subject — I have introduced a description of the difl'erent processes as they exist in each kind of manufacture ; and considering that the mechanical arrangements of which this volume treats apply generally to every description of spinning mill, its moving power, wheels, shafts, &c., being nearly the same in each, it is not necessary to multiply examples in cases where the details closely approximate and become almost identical in form and construction. I have therefore left to others the task of describing the machinery ; but I have given to oil, paper, and powder mills separate chapters. The importance of these Vm PEEFACE. different branches of industry establishes the necessity of their introduction, as also that of iron, which of all others is most intimately connected with the prosperity of our national in- dustry. From the improvements in the manufacture of iron we derive advantages and facilities for construction which did not exist in former days ; and it is not unreasonable that we should from this cause look forward to increased improvements in our mills, and a corresponding augmentation of the in- dustrial resources of the nation. In the production of this work, I have had the assistance of my former Secretary, Mr. W. C. Unwin, now resident at Kendal ; and subsequently of his successor, Mr. E. W. Jacob, who has prepared the drawings for this volume. Manchester : August 18, 1863. CONTENTS. SECTION IV. ON- MACHINEKY OF TRANSMISSION. CHAPTEE I. PAGE On Wheels and Puilies: — Introduction . . . . . .1 Wrapping Connectors: — Where employed . . . . . .2 Advantages and Disadvantages of . . . .2 Materials employed in the Construction of . . .3 Strength of . . . . .3 Table of approximate Widths of Leather Straps, in Inches, necess;u-y to transmit any required Number of Horses' Power . . 4 Toothed Wheels : — Introduction of . . . . . .4 Construction of Mortise Wheels . . . .5 Smeaton's Introduction of Cast-iron as a Material for Spiu- Wheels . 6 Eennie's use of Cast-iron in all the details of Millwork, as exempiitied in the Construction of the Albion Mills . . .7 True Principle of Constniction . . . .8 Tooth-cutting Machine . . . . .9 Spur Gearing: — Definitions . . . . . .11 Pitch of Wheels: — Eules for finding the Pitch and Diameter of Wlieels . .13 Table of Constants for Wlieel-Work . . . .14 Eules for finding the Pitch, Diameter, and Number of Teeth . .14 Professor Willis's Method of graduating the sizes of Wheels . 15 Teeth of Wheels: — The Principles which determine the proper Form . . .17 Formation of Epicycloidal and Hypocycloidal Curves . .17 Table showing the Eelation of Pitch, Diameter, and Number of Teeth , 18 Construction of Epicycloidal Teeth . . . .22 Construction of Involute Teeth . . .23 Professor Willis's Method of striking the Teeth of Wheels . . 28 Odontograph . . . . . .30 General Form and Proportions of Teeth of Wheels . . 32 Tables of Proportions of Teeth of Wheels for average Practice . 34 Table giving the Proportions of the Teeth of Wheels in Inches and Thii-ty Seconds of an Inch . . . . .35 CONTEXTS. Beatil Wueels: — Examiuation of the Curves Formation and Form of the Teeth Skew Be^-els: — Definitions and Method of setting out the Teeth The Worm and Wheel: — Description of Construction Stbength of the Teeth of Wheels: — Rules to be observed in Calculations Line of greatest Strain Table of Thickness, Breadth, and Pitch of Teeth of Wheels . . 43 Table of Relation of Horses' Power transmitted and Velocity at the Pitch Circle to Pressure on Teeth . . . .47 Table showing the Pitch and Thickness of Teeth to transmit a given Number of Horses' Power at different Velocities . . 48 Table showing the Breadth of Teeth required to transmit different Amounts of Force at a uniform Pressure of 400 lbs. per Inch . 49 CHAP. II. On the Strength and Proportions of Shafts:— The Factory System necessitates the use of long Ranges of Shafts . 50 Di'sasioN I. : — The Material of which Shafting is constructed . . .51 DmsioN II. Transverse Strain: — Resistance to Rupture . . . . .52 Rules for the Strength of Shafts . . . .54 Table of Resistance to Flexure. Weights producing a Deflection of j^th of the Length in Cast-iron Cylindrical Shafts . . 58 Table of Resistance to Flexure. Weights producing a Deflection of j^th of the Length in Wrought-iron Cylindrical Shafts . . 59 Table of Deflection of Cast-iron Cylindrical Shafts, arising from the Weight of the Shaft . . . , .60 Table of Deflection of Wrought-iron Cylindrical Shafts, arising from the Weight of the Shaft . . . . ,60 Division III. Torsion: — Coulomb's Deductions and Formula . . . .61 Bevan's Values of Modulus of Torsion . . . .63 Wertheim's Formulae for Cylindrical Bodies . . .64 Resume of Experiments on Cylinders of Circular Section . . 64 Resume of Experiments on the Torsion of HoUow Cylinders of Copper 65 Resume of Experiments on the Torsion of Bars of Elliptical Section . 65 Table of the safe Working Torsion for Cast-iron Shafts . , 68 Table of the safe Working Torsion for Wrought-iron Shafts . . 69 Table of the Diameter of Wrought-iron Shafting necessary to transmit with Safety various Amounts of Force . . .71 Division IV. : — Velocity of Shafts . . . . . .72 CONTENTS. XI Division V. On Journals: — Length of Journals . . . . . .73 Ultimate Pressure per Square Inch on Journals . . .74 Form of Journals . . . . . .74 Division VI. Fhiction: — Laws of . • . . . . .74 Eennie's Table of Coefficients of Friction under Pressiu-es increased continually up to Limits of Abrasion . . . .76 DmsioN VII. Lubeication: — Lubricants . . . . . .77 Method of effecting complete Lubrication . . .78 CHAP. III. ox cotjplijitgs for shafts and engaging and disengaging gear. Couplings : — Primitive Cast-iron square Coupling-Box . . .79 The Claw Coupling . . . . .79 Mr. Hewe's Coupling . . . . .80 The Disc Coupling . . . . . .80 The CirciJar Half-lap Coupling . . . .81 Kules for the Proportions of the Half-lap Coupling . .81 The Cylindrical Butt End Coupling . . . .81 Division VIII. Disengaging and Re-engaging Gear: — Throwing Wheels out of Gear with an Horizontal Lever . . 82 Throwing Wheels out of Gear with a Standard or Plummer Block and Movable Slide . . . . . .83 Disengaging Machinery by the Fast and Loose Pulley . , 84 Disengaging Machinery with the Sack Teagle Motion . . 85 CaUendering Machine Friction Clutch . , . .85 Friction Cones . . . . , .86 Friction Discs . . . . . .87 Friction Couplings . . . . . .87 Disengaging and Ee-engaging Clutch . . . .88 Two other Forms of ditto . . . . .91 Mr. Bodmer's Clutch . . . . .92 Division IX. Hangers, Plummer Blocks, &c., for carrying Suafting: — Pedestal for supporting Shafting on the Floor . . .93 Pedestal for bolting Shafting to a Wall . . . .94 Hanger for suspending Shafting from a Beam in the Ceiling . . 95 Hanger for suspending Shafting from the Floor . . .95 Hanger where great Strength is required . . .97 Hanger to connect two or three Ranges of Shafting . .97 Method of connecting Ranges of Shafting at Right Angles to each other by means of Plummer Blocks . . . .98 Table of the Diameters, Pitch, Velocity, &c., of Spiu- Fly-wheels of the new Construction . . . . .101 xu CONTENTS. Main Shafts: — Material, Diameter, &c. . . . . • Description of the Main Vertical Shafts Description of the Method of Gearing the Saltaire Mills Method adopted to lessen the Friction on the Foot of the Vertical Shaft Transmission of Power to Machinery at Obtuse Angles by the universal Joint ....••• Present Method by Bevel Wheels . . • • Table of the Length, Diameter, &e.. of Couplings. Coupling-Boxes, &c. 101 102 102 105 107 108 109 SECTION V. THE AJRRANGEMENT OF MILLS. CHAPTEE I. Mill Architectuee : — History of Mill Architecture . Old Form of Mill Architecture Improved Designs Fa9ade of Saltaire Mills The Saw-tooth or Shed Principle of Constriiction 110 113 114 115 115 CHAP. II. CoEN Mills: — History of . . . . . .117 Description of a Model Mill for the late Seraskier Halel Pasha . 118 Comparative Advantages of Bevel and Spur Gearing for driving the Grinding Mill . . . . . .123 List of WJieels and Speeds ..... 125 References ...... 125 The Taganrog IVIill : — Description of . . . . . . 127 Process of Manufacture . . . . .128 List of Wheels and Speeds ..... 130 References ...... 131 Floating Cobn Mill: — Description of one used at the Siege of Sebastopol . . .132 Comparative Merits of the Floating MiU . . .137 Details of MACHtNERY: — The Elevator . . . . . .139 The Creeper ...... 140 The Separator ...... 141 The Wheat Screen ...... 142 The Smut Machine . . . . .145 Another Form of ditto ..... 146 Tlie Framing or Stone Hurst of the Grinding Mill . . 147 The Stone Case and Feeding-Hopper . . .149 CONTEXT ?. xiii The Driving Gear The Mill -Spindle and its Appendages The Ehind PAGE 149 150 151 The Millstones 152 Adjustment of the Lower Stone Adjustment of the Mill-Spindle The Feeding Apparatus The Disengaging Apparatus The Stone-lifting Apparatus . The Dressing Machine 154 155 157 159 161 163 The Bolting MachiuL- 165 References 168 Balancing Millstones 169 CHAP. III. Cotton Mills: — The former State of the Cotton Factories Description of the Bombay Mills Processes thi-ough which the Cotton passes Speeds of Machines . List of "Wlieels and Speeds 171 173 174 180 181 CHAP. IV. Woollen Mills; — Properties of Animal Wools ..... 182 Description of a Mill for His Highness the Sultan . .183 Water- Wheel and Millwork .... 184 System of Gearing ...... 185 Processes through which the Wool passes — Sorting and Washing, Teasing and Opening, Carding, Eoving, Spinning, &c. . .186 List of Wheels and Speeds . . . . .189 CHAP. V. Flax Mills: — Examination of their Rise and Progress Description of the Narva Mills (Russia) for Baron Stieglitz Description of the Motive Power The Processes of Manufacture Spinning ..... List of Wlieels and Speeds, &c. 190 192 193 196 202 204, 205 CHAP. VI. Silk Mills: — Introduction of the Silk Manufacture into this Country The Old Form of Machinery . Introduction of the Spinning Mill Description of a MiQ in the South of England List of Wheels and Speeds The Process of Manufacture . 206 207 208 210 212 213 XIV CONTENTS. CHAP. VII. PAGE 0(1. Mills :— Description of Machinery for Compressing Seeds, as employed by tlie Natives of India and Ceylon .... 221 The Stamper-Press introduced by the Dutch . . . 222 Modem Improvements — Edge Stones, Steam Kettle, &c. . . 223 Messrs. Martin, Samuelson, & Co.'s Hydraulic Presses for extracting Oils 226 Process of Manufacture ..... 228 Comparative Eesults of the Stampers and Hydraulic Presses . . 228 Importation of Seeds, Extent of Manufacture, &c. . . 229 CHAP. VIII. BR Mills : — Origin of the Manufacture . . 230 Materials employed . . 231 Process of Manufacture . 235 Description of a Paper Mills . . 236 Machinery and Processes of Manufacture . 239 Increased Production . 241 List of Wheels and Speeds . 242 CHAP. IX. PowDEK Mills: — Composition of Powder Examination of the Ingredients Description of Waltham Abbey Powder Mills Detail of Iron Runner Table of the Composition of various Gunpowders List of Wheels and Speeds Gun Cotton 243 244 246 249 251 252 252 CHAP. X. Iron Mills: — The Mechanical Operations Motive Power Brown's Bloom Squeezers, Hammers, &e. Process of Manufacture Composition of Rollers Manufacture of Armour Plates 253 254 256 257 258 260 APPENDIX I. Processes of Manufacture of Wool 263 APPENDIX II. Armour Plato Manufacture Index . 268 . 273 LIST OF PLATES. To face Page I, Front Elevation of a Corn Mill of 3fi Pairs of Stones, Taganrog (Russia) . . . . . .127 II. Plan of do. do. .127 III. Sectional Elevation of do. do. .128 IV. Transverse Section of do. do. . 128 V. Elevation of tlie Oripntal Cotton Spinning Company's Mill, Bombay (India) . . . • • .173 VI. Plan of do. do. . 174 VII. Sectional Elevation of a Woollen Mill for HLs Highness the Sultan, Izmet (Turkey) . . . • .184 VIII. Plan of do. do. . 184 IX. Plate illustrating Foims of Toeth of AVhoels . . .32 X. Scale of Pitches . . . . . .33 Page 102, line 1, for 'shaft' read 'shafts' „ 113, „ 25, /o?" ' features ' rmfZ ' feature ' ,, 171, ,, 22, /or ' has ' rmfZ ' have ' „ 187, ,. 10, /or ' was' rcrt<^ ' were' „ 187, „ 11, /or 'and' ?rfiri^Z 'which' „ 188, „ 10, /or 'heated by steam of the circular form' rmo CO I-H W3 a >o o t^ CO C5 r-H CM -* "O C-l OS ■"^ (M (N Oi C-l CM c-l CM CO CO CO CO -f •* cr. 'O CO ^, t^ -*! 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CO CO C5 CD CM C5 cc CM o ■o ■* CO 00 ^ CM CO lO t^ C5 f— 4 CM ^f o o CO t^ t-H 'i' 00 CM LO C5 CO >o 00 ^ US CO 00 (.H ■* t^ o '^l I--. o CO o CD CM CT> lO ,_( CO o CM o CO t— I o t~ CM oo ^ C5 >o f-H CD O) CO -*l o 1^ CM t^ CM CO ,-H CO ,-H LO r-, ^ CM CM CM C~l CO CO CO CO TTl -# -* ^^ «3 o CD CO t^ t^ 00 CO C3 o rt — CJ CO r^ CO o ^ CM rt ^ o CO CO ^ CM o l^ LO CO ~ o C5 00 00 00 ay cc 00 00 CO OO r^ t:^ t^ l^ t~- t^ CO CD o CO LO LO lO t^ CS r-t CO •-O t^ o J—t CO >.o t^ C3 CO t^ ,_( 'O C5 CO t-- ,_H •o o '"' '"' ^ CM CM CM CM CM CO CO CO CO CO -*< ■<*< »o ws ■o o CO I:^ t^ t^ CO (N ^ o Oi on r^ CD o lO ■* CO CM o on CO -# CO ^ o on CO ^rM t^ CO Ol lO o CO CM 00 Tt< o CO CM 00 o f-H CO lO t^ 05 CM ^ CO IM ■>!»< lO t^ C5 o Cfl CO wo »^ t» o ,-H lO 00 r~4 Tt< t^ o ^ t^ ^^ CO '"' r-4 ""* '"' CM CM CM CM CM CO CO CO CO ■* Tt< rj< o >o lO CO CD ■* ^ CO CM C<1 rt — a o GO t^ CD CO Tf CO CM o Ci 00 CO LO CO CM «2 t^ a r~i CO lO t^ 00 ^ CM ■* CD 00 CM o o ■* !>. LO o> CO t^ a o r-4 CO ■T< lO CO 1:^ C5 o 1— < cq oo CO 00 f-4 CO >-Cl m o CM >o ■"* ■"* ■"' '"' ■"* '"' ^ ^ CM CM CM CM CM CM CO CO 00 CO ■* ■* -i< Ti< o o CO iC o ^ '^ CO CO CM CM rt ^ o C3 on t^ CO LO -t< 00 CM CO 1—t C5 t^ 'O CO »— ( C5 1--. o CO i-H C5 o o CO CM 00 ^ o o CM oo o »>. t^ 00 o o - - CM CO rj< >o >o l^ o CM CM CO CM LO CM CI CO CM o CO CO o •-0 13 o lO 'O o "O o -* ^ >o »o CO CO l^ t^ cc 00 cs C5 '-' t-H CM '-' '-' o CO t^ OC C5 CM 20 OX MACHINERY OF TRANSMISSION. Fig. 190. Fig. 191. rolls within it, the hypocycloid is a straight line forming a diameter of the base ; 2nd, if through the points of contact of the generating circle and the base, and the point describing the epicycloid, straight lines be drawn, these straight lines will be perpendicular to the curvature of the epicycloid at these points. Thus, for example, b c'" drawn from the point of contact B to the describing point c"\ is a normal to the curve at that point ; and similarly a f' is a normal to the curve at f'. Suppose in the same plane three circles exy (fig. 191), w^hich touch each other in the point A, and w^hose centres F B G are consequently in a straight line. Let one of these circles be made to revolve round its centre, and force the other two to turn round their "WHEELS AND PULLIES. 21 centres, which we suppose to be fixed, moving these circles by the point of continual contact A, common to the three cir- cumferences; it is evident that all the parts of the circum- ference of the circle made to revolve will be applied in succession to every part of the circumferences of the other two circles, in the same manner as if the two circles R and x remained immovable, while the third, y, revolved on the circumferences of the other two. Hence, if we suppose a style fixed to the circumference of the circle y, movable round its centre, the three cii-cles having been obliged to turn by the motion of the one which has carried along the other two ; when the style is at e, if each of the two arcs A c and A h be made equal to the arc a e, the style will have described on the mov- able plane of the cii'cle e, on the exterior part of which it revolves a portion ce of an epic3^cloid, and on the movable plane of the circle x, within which we may consider it to re- volve, a portion e h of a h^^pocycloid. {Camus.) These two epicycloids traced out at the same time by the style E affixed to the circle y, will touch each other in the point e ; for the straight line A e drawn through A, where the gene- rating circle y touches its bases r and x, will be a normal to the two epicycloids. The same will be true in every position of the circles, viz. that the epic3'cIoid and hypocycloid will have a common normal passing through a. Hence, if e c and E H be the faces of two teeth on the wheel and pinion r and X respectively, the condition of uniform motion already given will be complied with, the teeth Avill be of true form, and if the hypocycloid e h be moved by the epicycloid e c, or vice versa, the wheel and pinion r and x will move precisel}'' as if they rolled together at their pitch circles. Wheels usually have their teeth constructed of such a form, that the flanks or parts within the pitch circle are bounded by straight lines radii of the pitch circles. Bearing in mind the property already stated, that the hypocycloid described by -a generating circle of half the diameter of the base is a straight line forming a diameter of the base, we may so arrange our generating circle in describing the teeth of wheels as to comply with the above rule. By taking a generating circle y of dia- meter equal to the radius of the base x, the hypoc3'cloid e ir 22 ON MACIIIXERY OF TRANSMISSION, will be part of a radius of x ; or, in other words, a radius b h of X will always touch the epicycloid c e described without the circle e, by a generating circle t, of a diameter equal to the radius of x. And the angle B e A being the angle of a semi- circle, will always be a right angle. That is, the perpendicular to the straight line b h, at the point of contact with the epicy- cloid E c, will always pass through A. We have hitherto supposed the circles moved by contact at the point A, in order to explain the generation of the epicycloid c E and straight line e h ; but if we suppose these already de- scribed, the former being fixed to the circle R, and the latter to the circle x ; then if e h roll by contact on the epicycloid c e, it will move the circle e precisely in the same manner as if the circle were moved by contact at a. Construction of Epicyeloidal Teeth. Since every tooth in a wheel is of precisely the same form, it is sufficient to construct a single pattern tooth of true epicy- Fiff. 192. WHEELS AND PULLIES. 23 cloidal curvature, which may be used in setting out all the other teeth. First method, when the generating circle is the same for wheel and pinion, the face of the tooth an epicycloid, and the flank a hypocycloid. Construct two templets A and b (figs. 192, 193) having their faces arcs of the pitch circle of the wheel for which the tooth is required, and a third templet c cut to an arc of the intended generating circle of the epicycloid. Fix a steel tracing point _p in the edge of the templet C, and for convenience a board f, on which to draw the tooth, may be fixed beneath the templet b. Mark off on the board f (fig. 192) the pitch circle of the wheel de, and take distances ab, b c equal to the pitch of the teeth, and distances a a', b b' equal to the thickness of the teeth. If then Fig. 193. r ■ n A \. E 3^ c F ^\ !U— gt the templet c be placed touching b, and wdth the tracing point 'p coinciding with one of the marks as a, and be rolled towards E, the point will trace out an epicycloid ap on the boai-d f, which will form one face of the tooth. Next let the point -p be made to coincide with a', and the templet c be rolled to- wards D, the other face of the tooth will be described. 24 ON MACHINERY OP TRANSMISSION. To draw the flanks, the templet A must now be fixed on the board f, with its face in contact with b ; remove b and describe hypocycloids (fig. 193) from a and a', by rolling c on the inside of the pitch circle. The length of the teeth is usually fixed as a proportional part of the pitch, but the least necessary length may be found experimentally by replacing the temj)let b on the board f, and making ]J coincide with a, roll c towards e till it touches b in 6, the corresponding face of the next tooth ; mark then the position of the tracing point, and through this point draw an arc from the centre g of the wheel : this arc will mark the extremity of the tooth, and the arc gp will be the true radius of the wheel. This process, which, though complicated in description, is very easy in practice, must be repeated with two templets cut to the pitch circle of the pinion, the same generating circle c being employed ; a similar pattern tooth will thus be found for the pinion, which will work with that already found for the wheel. The usual custom in practice is for the millwright first to describe the epicycloidal and hypocycloidal forms of the teeth required in the wheel and pinion ; he then con- structs two model teeth, one for the wheel and the other for , the pinion, and from these he determines the true curves, and by means of his compasses transfers the same to the wheels or patterns on which these forms are to be impressed. The gene- rating circle, it may be observed, must not exceed in size the radius of the pinion, or it would give rise to a weak form of tooth, thinner at the root than at the pitch circle. Second tneiliod, where two generating circles are employed, in order that the flanks of the teeth may be straight lines radii of the wheel and pinion respectively. It is the usual practice of millwrights to make the parts of the teeth of wheels within the pitch circles radii of the wheel. Now, we have seen that a hypocycloid described by a generating circle equal in diameter to the radius of the wheel would be a diameter of the wheel. If, therefore, the flank of the tooth of the wheel and the face of the tooth of the pinion be de- scribed by a templet cut to a radius equal to half that of the wheel and the flank of the tooth of the pinion and face of WHEELS AND PULLIES. 25 that of the wheel be described by a templet cut to a radius equal to half that of the pinion, then these teeth will work together truly, and will have radial flanks. Since it is unnecessary to describe the flanks of such teeth by templets, there will be needed only one templet cut to the pitch circle of each wheel, but templets of two generating circles are required. In other respects the method is identical with that already described. The great defect of this method is, that neither the wheel nor pinion will work accurately with a wheel or pinion of any other diameter than that for which they were originally made, and thus a vast number of wheel patterns must be made to fulfil the requirements of practice; whereas wheels described by the previous method will work equally well with all other wheels the teeth of which have been described by the same generating circle — it being understood that only the parts of teeth luithout the pitch circle of the wheel roll on the parts luithin the pitch circle of the pinion, and those with- out the pitch circle of the pinion on those within the pitch circle of the wheel. , Hence Professor Willis has been led to suggest that for a given set of wheels a constant generating circle should be taken to describe both the parts without and within the pitch circles of the whole series, instead of making that circle depend on the diameters of the wheels. In this case the first solution must be employed, and the flanks of the teeth will not be straight ; but the great advantage is gained, that any pair of wheels in the series will work together equally well. To determine the proper size of the generating circle, we must remember that a tooth of weak form is produced when the generating circle is greater than half the diameter of the wheel. Hence the generating circle may be best made of a diameter equal to the radius of the smallest pinion of the series which are to work together. The Rack is the extreme case of a wheel, or may be con- sidered as a wheel of infinite radius. It may be described by either of the methods above, only noting that, if the second method be employed, the generating circle which traces the face of the teeth of the wheel becomes a straight line, and the epicycloid becomes an involute. 26 ON MACIIINEEY OF TRANSMISSION. If the teeth of a series of wheels and of a rack be described by the same generating circle, any of the wheels will work with equal accuracy into the rack. Involute Teeth. The Involute, the curve traced by a flexible line unwinding from the circumference of a circle, is called an involute. Let P and w (fig. 1 94) be the Fig. 194. pitch lines ofa wheel and pinion, and let A and b be their centres. From A and b describe two circles d c, with radii A h and B 6 of the wheel and pinion respectively ; so that AC : Bc :: AD : B c Let m 71 and o p be two in- volute curves described by flexible lines unrolling from the circles d and c respectively, and touching at b. Then if bc, bi) be drawn tangents to the circles at the points d and c, they are also in one straight line, because they are both normals to the curves at b. It may also be shown that the line c D intersects A b in c, where the pitch lines touch. Hence we have found two curves such, that the line perpen- dicular to their common tangent passes in all positions of the wheel and pinion through c, which is the sufficient condition of their uniform motion, if moved by the sliding of the curves instead of by contact at c. Hence, if the wheels be constructed with teeth formed to these involute curves, they will work with perfect regularity of motion. In practice, the chief condition to be observed is to diminish the pressure on the axes, which is the chief defect of this form of teeth. The common tangent should be drawn through c, WHEELS AND PULLIES. 27 making an angle with A b, not deviating more than 20° from a right angle. Involute wheels have the double advantage that they work equally well if, through the wear of the brasses, the wheels have receded from one another ; and any involute wheels of the same pitch and similarly described — that is, having the common tangent to the base circles passing through the point of contact of the pitch lines ; or, in other words, base circles proportional to the primitive radii — will work together. Mr. Hawkins, the translator of Ccfnius, first proposed a simple instrument for describing the teeth of wheels to an involute curve. It consists of a straight piece of watch-spring a b (fig. 195), with a screw at one end, and filed away at the Fig. 195. a c h ((2) O) n c h edges so as to leave two teeth or tracers, c c, projecting from the edges of the watch-spring. At 6 a bit of wire is put through, and riveted, so as to form a knot by which the spring- can be firmly held and stretched, as it is unwound from the base on which the involute is generated. This watch-spring -is screwed to the edge of a templet A, curved to the radius of the base circle of the involute ; and this being placed so that its centre coincides with the centre of the wheel, and revolved to bring one of the tracing points c in succession to each of the points at which corresponding faces of the teeth cut the pitch line, a series of involute curves may be described by unfolding the watch-spring, whilst keeping it firmly stretched tangen- tially to the sector to which it is fixed. The sector a must then be turned over, and the involutes of the opposite faces of the teeth struck in a similar manner. 28 ON MACHINERY OF TRANSMISSION. Another plan is to employ a straight ruler instead of the watch-spring, a tracer being fixed in its edge. This shows that the involute is an epicycloid generated by a straight line. The ruler must be kept in contact with the base circle, and the tracer brought in succession to all the points in which the faces of the teeth cut the pitch line. Hence, to describe a wheel with involute teeth, the line of centres must be drawn and divided proportionally to the number of teeth in the wheel and pinion. Draw the pitch line ; divide the pitch line into the same number of equal parts as there are teeth in the wheel, and at these points mark out the thicknesses of the teeth all round. Draw the tangent to the base circles, making an angle of about 80° with the line of centres, which will cfive the radius of the base circle drawn touching it. A templet must be made to this radius, and then the involutes may be drawn by either of the preceding methods. Allowance must be made to permit free play of the teeth in the spaces, the teeth being somewhat shorter than the dis- tance between the bases of the involutes. But wheels of this figure require but little play in the engagement. In the case of racks, the rack -teeth are bounded by straight lines perpendicular to the tangent drawn from the point where the pitch lines touch, to the base circle from which the involutes of the wheel are struck. If the teeth of the rack be made rec- tangular — that is, bounded by lines perpendicular to the pitch line — the involute must be struck from a base circle equal to the pitch circle of the wheel. In the former case there is a downward pressure on the rack ; in the latter, the teeth of the wheel touch those of the rack in a single point — namely, the pitch-line of the latter. Professor Willis''s Method of Striking the Teeth of Wheels. ' In practice, the custom of describing the teeth of wheels as arcs of circles, has, from its simplicity, been generally adopted. The methods already given, however simple, when adopted in the formation of a single tooth, become tedious in their appli- cation to wheels of large size ; and to this must be added the imperfect comprehension of their advantages by the millwrights charged with the task of designing wheel patterns. WHEELS AND PULLIES. 29 Circular arcs struck at random, according to the judgement of the millwright, are often employed ; and even where better prin- ciples have been introduced, it is common, after describing a single tooth accurately, to find by trial a circular arc nearly corresponding with its curve, and to employ this in marking out the cogs of the required wheel. Seeing the advantages of the circular arc, and believing that it is not objectionable if only the employment of it is guided by true principles, Professor Willis has rendered this great service to practical mechanics — he has shown how, by a simple construc- tion, the arcs of circles may be found, which, used in the con- struction of the teeth of wheels, will work truly on each otlier. FiK. 196. Let AB (fig. 196) be the centres of ;i wheel and pinion, and c the point of contact of the pitch circles on the line of centres. Through c draw c c (/ at any angle with A e. Assume c as the centre from which to describe an arc for a tooth of the wheel a. Draw c d perpendicular to c c c', and from a through c draw A c D, meeting c d in d. Lastly, from d through b draw d b c', meeting: c c c' in cf. Then a small arc drawn from c with radius c c as a tooth for the wheel a, will work correctly with a small arc drawn from c', with a radius ^-DejthteyoiidHtclilLae - a.g '<^Depth. -within Jitci Ime = "bg i<- Thickness of Tooth. =- cf ^ ^ 1^ Width, of Space - df i^-Wbrismg depth, of Tooth - ae «- Whole depth, cf Tooth - ab London : Xongman >(- C - ON THE TEETH OF WHEELS. 33 of epicycloidal teeth, struck by a single generating circle rolled without the pitch circle for the faces, and within it for the flanks. This is the best system, as any pair of wheels so struck, with the same generating circle and of equal pitch, will work together. Fig. 3 shows the common form of epicycloidal teeth, the flanks being- straight. In this case the faces of the rack are struck by a generat- ing circle half the diameter of the wheel, and the faces of the wheel, being obtained by a generating circle of infinite diameter or straight line, become involutes. Fig. 4 gives the form of teeth described as involutes, the curve being continuous, and, in the case of the rack, a straight line perpendicular to the tangent to the base circle. In these teeth it is possible to work with very little play. They are a good form for wheel and rack working together, the pressure on the journals being in this case less objectionable. Fig. 5 shows the teeth of a large wheel, traced from one of my own patterns, to exhibit the form and propor- tion which practice has shown to be desirable. In these teeth the pitch cd being 2^ inches, the depth of the tooth or distance a b is i^ths or -fths of the pitch. The pro- portions of the parts may be given as follows : — Pitch = c d Proportional Part. 1-00 Inches, 2| Depth = Working depth = Clearance = a h a e eb = 0-75 0-70 0-05 = 1| 1 8 Thickness = cf = 0-45 = li Width of space = Play ovfd, cf = Length beyond pitch line = fd ag = Ooo 0-10 0-35 = If 1 4 7 8 Taking these proportions, we may construct a scale which shall give directly the corresponding numbers for any pitch. Taking a vertical line, and dividing it into eighths of an inch, we get the scale of pitches (Plate X.). Draw lines perpendicular to this, and on any one of them mark off a series of distances equal to the clearance, depth, thickness &c. of the teeth cor- responding to that pitch. Through o and these points draw the lines shown in the figure ; they will divide the lines corre- sponding to all other pitches in the same proportion. It is usual to allow a greater amount of clearance in small VOL, II. D 34 ON MACHINERY OF TRANSMISSION. wheels than is necessary in large ones. Very varying propor- tions have been given by different millwrights, yV^^' tV^^' -jL-th and -^th of the pitch having been used in different cir- cumstances, even with the best mill-work. In the scale (Plate X.) this has to a certain extent been taken into account ; y^-th of the pitch is allowed in smaller wheels, decreasing to ^sth in the largest ; hence the lines are not absolutely straight, but are slightly curved, except that for the whole depth of the tooth, which quantity has been assumed to vary directly as the pitch. Assuming that this scale represents with sufficient accuracy the proportions which practice shows to be best in average cases, we may construct a table for the guidance of the millwright. From this he must vary in cases where it appears necessary to allow more for defects of workmanship, or to permit less "backlash ;"* it being understood that the table will only apply in cases where the teeth are formed with an approximation to the true mathematical figure. In wood and iron gear where the teeth are carefully cut, very little if any clearance is necessary, as they work much better when the tooth of each wheel fills their allotted spaces. It is. Tables of Proportions of Teeth op AVheels for A-tokage Practice. Clej Pitch. n P irauce nd ay. Depth beyond pitch line. Depth within pitch line. Working depth. Whole depth. Thickness of tooth. Width of space. i 06 •16 •22 •32 -38 ■22 •28 5 4 08 25 •33 •50 58 •33 •42 1 10 335 •435 •67 77 •45 ■55 11 12 42 •54 •84 96 •56 •69 u 13 51 •64 1^02 15 •68 •82 ll 14 60 •74 1^20 34 •80 •95 2 16 685 •845 1^37 53 •92 1^08 H 17 775 •945 1^55 72 1^04 1-21 2i 19 86 1^05 1-72 91 115 1-35 2| 20 95 1^15 1-90 2 10 r27 1-47 3 22 04 r26 2-08 2 30 r39 1-61 H 23 13 1^36 2-26 2 49 1'51 1-74 H 25 215 1-465 2-43 2 68 1-62 1-88 H 26 305 1-565 2-61 2 87 r74 2-01 4 28 39 1-67 2-78 3 06 r86 2-14 H 31 565 1-875 3-13 3 44 2^09 2-40 5 34 745 2^085 3-49 3 83 2^33 2-67 5i 37 925 2-295 3-85 4 21 2^56 2-93 6' 40 2-10 2-50 4-20 4-60 2^80 3-20 A teclinical expression for reaction on the back of the teeth. ox TUE TEETH OP WHEELS. 35 however, different where wheels have to gear together direct from the foundry, where the teeth are not imfrequently deranged in the act of moulding in the sand. This table gives the number to the nearest hundredth of an inch. It may be converted into the ordinary scale of eights by the following table : — Thirty Seconds of an Inch, 1 2 3 4 5 6 7 8 9 10 CorresjTOiiiling Decimal. -031 •062 •094 •125 •156 •188 •219 •250 •281 •3125 As, unfortunately, decimal scales are not yet much used by millwrights, the following table has been prepared, giving the numbers in the preceding table in thirty seconds of an inch, such changes being made as will reduce as much as possible the errors of employing this rough standard. The former table is to be preferred where it can be used, but in other cases the following one may be relied on. The left-hand figures in each Table Gittng thi; Proportions of the Teeth of Wheels in Inches and Thirty Seconds of an Inch. Pitch, inches. Clearance. Depth beyond the pi'tch line. Depth within the pitch line. Working depth. Whole depth. Thickness of tooth. h 0" 2 0" 5 0" 7 0" 10 0" 12 0" 7 3 3 8 11 16 19 10 1 3 11 14 22 25 14 li 4 13 17 26 30 18 H 4 16 20 1 4 21 1* 4 19 23 1 6 10 25 2 5 22 27 1 12 17 29 2:^ 5 25 30 1 18 23 1 1 2i 5 28 33 1 24 29 1 5 ^ 6 31 37 1 30 2 4 1 8 3 7 1 1 1 8 2 2 2 9 1 12 H 7 1 4 1 11 2 8 2 15 1 16 H 8 1 7 1 15 2 14 2 22 1 20 H 8 1 10 1 18 2 20 2 28 1 23 4 9 1 12 1 21 2 24 3 1 1 27 4i 10 1 18 1 28 3 4 3 14 2 3 5 11 1 24 1 35 3 16 3 27 2 10 H 11 1 30 1 41 3 28 4 7 2 18 6 12 2 4 2 16 4 8 4 20 2 25 36 ON MACHINERY OF TRANSMISSION. column are inches, the right-hand ones thirty seconds of an inch, the denoroinators of the fraction being omitted. Bevel Wheels. Hitherto we have considered only that case of toothed wheels in which the pitch lines are in one plane. We have now to examine the modifications which are necessary when the axes of Fig. 199. the wheel and pinion are inclined. It was shown in the pre- liminary Chapter* that in this case motion might be transmitted by the rolling contact of the frustra of two cones. If, therefore, * Mills and Mill-work, Vol. I., p. 46, § 68, 69. ox THE TEETH OF WHEELS. 37 teeth be applied to these frustra, in the same manner as in spur gearing they are attached to cylindrical surfaces, bevel gearing will be formed acting on the same principles of sliding contact which we have already discussed. Let ABC, A c D (fig. 199) be two cones rolling in contact ; take any other cone a e c also rolling in contact with A b c, in the line A c. As these cones roll together, the generating cone A e c Avill describe an epicycloidal surface j) qr s on the outside of the cone A c d, and a hypocycloidal surface ptvs on the inside of the cone a c d. These surfaces will touch in the line j) s, and will have a plane normal to their common tangent passing through A c. If, therefore, these surfaces be attached respect- ively to the cones ABC, A CD, and the motion of one cone be communicated to the other through the sliding contact of these surfaces, the motion will be uniform, as if the cones were driven by rolling contact at A c. The curves pt, p q, lie in reality on the surface of a sphere of a radius equal to A c ; but in practice, in bevel wheels, a small frustrum of a cone, tangential to the sphere at the circumference of the pitch line, is substituted for the spherical segment. Thus draw F c G (fig. 199) perpendicular to A c, cutting the axes of the cones in f and G. Let these lines revolve over the pitch lines of the cones and describe the narrow frustra. Then the epicy- cloidal surfaces may, without sensible error, be supposed to lie in these frustra, and to be generated there by the revolution of a generating circle c E. Imagine the surface of these frustra to be unwrapped so as to lie in one plane, they will form parts of circular annuli. Thus let ABC, ACD (fig. 200), be two conical frustra ; draw f c G as before, perpendicular to the line of contact a c. From G, with radii G H, G c and G K, describe the circles K L, cm, h n ; and from f, with radii f k, f c, f h, describe similar circles K p, c Q, he; then the surfaces KPKHand KLNHwill be developements of the frustra CD, c B. Let these be treated as spur wheels, and c Q, c M being treated as the pitch lines, let teeth be described by a describing circle in the method already explained for epicy- cloidal or other teeth. If, then, the plane on which these have been described, and which we suppose of drawing paper or other flexible material, be cut along the arcs K r, h b, k l, h n, 38 ON MACIimERY OF TEANSMISSIOX. Fig. 200. the circular aiiuuli may be wrapped round the frustra c B, C d, and the forms of the teeth traced off upon them. Fjs. 201. The axes of bevel wheels are in practice, in the great generality of cases, at right angles. Fig. 201 shows such a pair ON THE TEETH OF WHEELS. 39 of bevels, with the frustra of the extremity of the teetli deve- loped in the manner described. Skeiv Bevels. When two axes or shafts, which have to be connected by bevel wheels, do not meet in direction, it is usual, as stated in the preliminary Chapter,* to introduce an intermediate bevel wheel with two frustra. But the same object can more easily be accomplished by adopting skew bevels. Let B p g (fig. 201) be the place of one of the two frustra, a its centre, and a e the shortest distance between the axis of FiOtOCCO'M-t<«X-_'M-;<-OXOTl-T'-Oa: _ _— _ 4; a i-iiMeOTCiooaO'-iccot^cic^i-^^aCwCC'Ot^Ci— 1-fwOco r-Ci-c,-tr-lr-.'5O«5OiOO«OO>-'5OOCO M C^ «3 00 i-< CO t^ ^ 'O X -M C; t^ «0 •>! t~- lO 'M t— cq l>. 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O •^ VO >p p t;^ Ph i/r t- ■* C5 CO CO iIh oo CO 1^ o i-b o O i1h r- ^ b b (N K T— ( c« b ^ •a IM I-H ca co ■* CO t^ C3 CO US t^ o >o 00 W5 CO E o s — ' -"^ '-' "-I C<1 p C<) 9 C5 o o p (M M "? t^ I-H (N b- p & c CO -* i^ , — 1 t~ ■^ C-1 o o ,-H CO cb o ^ o >b lb t^ b !3 J s '"' '"' (M CO Tt< lO CO »^ oo Ci CO CO o IM CO (M CO s -4J p^'i^ "5 >c o op ifi ,-H CO CO p op p p op p t;~ p p l;- rt — < CO i> o ^ 6 l^ -* (M |Zh i1h C-5 «) cb o b CO b b . '" • r— t I-H IM (M CO Ttl «5 o t~ oo C5 CO t^ o lO (M (M f4 1 CO "3 > ,-"=^ lO ^ (M a> ^ ■* o C<1 ^_^ C-1 Tfl t^ o o t^ >o lO ^ » Ci cu c^ J-~ CO !M T-H CO "? P M o p op CO "?* •rf CO 'ti P ■^ p p *^ K M -^ «b OJ CO 1^ o ■-I ■— ' ■—1 H . i-H C5 lO o (M I-H I-H C<1 CO lO oo -# lO o Oi o ,-H CO CO f^ »o P- l^~ >p C5 >p t^ CO CO 1-^ i ^ P (M 05 O si A-( (N •^ O Oi (M «3 c> CO oo cb oo ■* b cb OO lb CO m I-H I-H r-i cq (M CO CO ■* «o CO l>. C5 ■-I 1 . C<1 lO t^ ^ CO 00 00 CO •^ «^ ^ oo 05 o t^ o lO >o t-^ 2 CO •^^ Ci t;^ i^ o 'O CO 'J' lO p OC' oo Op ^ p r^ p s H ^ ^ C<1 ■* lb t^ o 1^ ■^ cb a> (N cb b oo J^ t^ oo fM *"* *"* *"* *"* (M o 05 N CO CO O CO o oo «3 Oi ^ Ah ,-1 CO »p Oi CO oo -* cp P CO CO p Op p I--. p »;- ^ K r-H 1^ cq n CO -* »b cb t^ CJO b c-l lb b ^ c -iM XI I-l '"' '"' '"' C^ (M o >o CD Eh c ON THE TEETH OF WHEELS. 49 E^ "2 s s. » = O 'S. o >. _o > ^ i >-'3 O o o 6 6 .;H.^Cq-*00-;HMOCCOOC000C.^ U5 _c C5 00 O --I © i t^ t^ O C = » C<1 lO 6 b 30 O OJ co<>pMpip.7^c^ww»bor^aoO'^'i-ir3>i)or--300 CJ t- i 01 •* :OKpOO5O5(p05C5C00030J--I^cpp«5'P'p-*-* obAcN^^^M-*'b^-C5•^co'^^-c>•^ct>'o^~35^ 1— i>-lrt^r-(!NC-l'MClC^CO . J m CD 6 6 oO'-i-^t^^ocncflOb- «3epi--«scoo ^,_,^rtC-ir-ic<)cocosoco^-* e<5 ~ O Ci - J r-->oC3t^os^=-o'NSa;ipcc>i^6-*'^'-':Ko^-iicot^A--;cSl^l 1 ' ' Number of horses' ■3 s 2 1-1 I-1 COtJ'iOOKSO'OOOOOOOOOOOOOO© rHi-i0Ot~0005©^I^CC'*i0O VOL, II. 50 CHAPTER 11. ON THE STRENGTH AND PROPORTIONS OF SHAFTS. The system of transmitting power from a common centre to a large number of machines, at some distance, is comparatively modern. In the operations of spinning and weaving by a con- secutive series of machines, placed in rows, shafting became essential for distributing the power of the common prime mover. At first, the machines were brought as close to the prime mover as possible; and the early construction of mills — when the water- power was divided into separate falls — must be fresh in the recol- lection of many persons now living. In some cases, before the introduction of the steam engine, it was the custom to have a separate water-wheel to every machine, thus splitting up the power into as many parts as there were machines, or pairs of machines, to drive. In process of time, it was found more con- venient, on the score of economy, to husband the water and con- centrate the prime movers ; hence one large water-wheel was constructed, around which the machinery was arranged, either in rows or otherwise, as best suited the work to be performed. This principle, of the concentration of the motive power, destroyed the old system of separate buildings, and led to the employment of a large number of machines for the various pro- cesses of manufacture in one building. From this we derive the Factory system, in which any number of processes are carried on, the machinery being distributed over the different floors of a large building, and receiving motion from a single prime mover at a convenient distance. In this way, the power is conveyed by lines of shafting coupled together in lengths, adapted to the bays or divisions of the building. At first, the buildings were short, and shafting of great length was not re- quired; gradually, more and more machines were concentrated ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 51 in the same building, and shafting of 200 or 300 feet in length became necessary. To show to what an extent this system has been carried, it may be mentioned, that in the large mills at Saltaire, the shafting, if placed in a single line, would extend for a distance of more than two miles. This progress has been chiefly due to the introduction of the steam engine, in place of water-wheels, because the available power is no longer limited by the circumstances of the locality in which the mill is placed. This concentration of a great number of machines in one building, is peculiar to the Factory system; and in the present highly-improved state of mechanical science and its application to the production of textile fabrics, it has become essential to economy in the manufacturing processes, that they should be carried on in the same building. Spinners and manufacturers are fully aware of the advantages peculiar to this system of con- centration, so much so, that out of what would formerly have been considered a mere fractional saving, large profits and large fortunes are now made. In fact, the amalgamation of the dif- ferent processes under one management and under one roof, gave rise to the shed system, where the operations of the manu- facture of cotton are carried on under what is called the " saiv- tooth''^ roof, in order to bring the whole on the ground-floor under one inspection. 1. The Material of wkich Shafting is constructed. The selection of the material for shafting is of great import- ance, and the uses to which it is to be applied require carefid consideration. Formerly wood, with iron hoops and gudgeons, was universally employed ; then cast-iron was introduced and subsequently wrought- iron has in most cases superseded both. Wood, indeed, has become obsolete; but cast-iron is as good as, if not superior to, wrought-iron, in certain cases. The main and vertical shafts of a mill are generally of cast-iron, both on ac- count of its cheapness, and its high resistance to torsion. The vertical shafts, which convey the power from the first motion wheels to the difl'erent rooms of the mill, are more rigid and less subject to vibration when of cast-iron ; even the main hori- zontal shafting, when of large dimensions, is, if substantially fixed, quite as good, when of the same material, and much 52 OX MACHIXERY OF TRANSMISSION. cheaper than wrought- iron. AMiere the shaft is exposed to impact, or any irregularity of force, wrought-iron has the superiority; but in other cases, when the castings are sound and good, cast-iron may be employed with perfect safety. The dimensions required for a shaft, transmitting any given force, will depend on the resistance of the material of which it is composed. Consequently, the selection of material must be deter- mined by the necessity for strength. Shafts may be considered as subject to two forces: a force' producing simple flexure, arising from their own weight, the weight of the wheels and pullies, and the strain of the belts; and a twisting force or torsion, arising from the power transmitted. If the flexure be great, the brasses will be much worn, vibration becomes considerable, and the disintegra- tion of the machinery goes on in an accelerating ratio ; it is there- fore necessary to proportion shafting to the simple weight and direct transverse strain it has to sustain, so as to reduce the flexure within exceedingly narrow limits. In addition to this, the shafting, having to transmit a torsive force, must at least be capable of transmitting it without danger of rupture. In long and light shafting the tendency to flexure is usually greater than that to rupture by torsion ; the former consideration will therefore determine the size of the shaft. In short axles, etc., the danger from flexure almost disappears, and the strength of the shaft is determined by its resistance to torsion only. In all cases both conditions must be complied with, if security and permanence are to be obtained. 2. Transverse Strain. Resistance to Rupture. The general formula for resistance to rupture, in the case of a bar or beam supported at each end and loaded in the centre, is adc W = -j- .... (1.) where w is the load in the centre, a the area of a section of the bar, perpendicular to the length ; d the depth of the bar, and I its length. In this case c is derived from experiment, and is constant for similar bars or beams. ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 53 For rectangular bars this formula becomes, c b (P , , , ^ = -r ^'-^ where 6 is the breadth and d the depth. The value of c, for rectangular bars found by Mr. Barlow, for various materials, is given in the following table. In appl3dng these numbers to calculations, it must be remembered that a and d are to be taken in inches, and I in feet ; then c, the centre breaking-weight, is found in lbs. AMien the beam is supported at one end and loaded at the other, the formula is ^ = -u ^^-^ Value of c for different Materials. lbs. English Malleable Iron 2050 Cast Iron 2548 Oak 400 Canadian Oak 588 Ash 675 Pitch Pine • 544 Red Pine 447 Riga Fir • . . . . 376 Mar Forest Fir 415 Larch 280 In my own experiments * I found the value of c for cast-iron to range from 1606 to 2615, the mean value being about 2050, as given above for malleable iron. Wrought-iron ranges from the value given above to 3000 lbs. For cylindrical shafts supported horizontally the ultimate re- sistance to ruptiu'e is about 15000# ^ W = -, tor wrought-iron, 19000# ^ = -J tor cast-iron, * On the Application of Cast and Wrought-Iron to Building Purposes, p. 74 et seq. 54 ON MACHINERY OF TRANSMISSION. where W is the centre-breaking weight in lbs., d the diameter, and I the length between siipyjorts in inches, the shaft being sup- ported at the ends and loaded in the middle. If the cylindrical shaft be loaded at one end and supported at the other, these formulae become 7500cZ3 W = -, tor wrought-iron, 6 9500 rP = tor cast-iron. t If a beam be uniformly loaded over its entire length, it will sustain twice the load that would break it if placed at the centre. If the load be placed at any point intermediate between the centre and the ends, the breaking weight may be found by the following rule : — Divide four times the product of the distance in feet, of the weight from each bearing, by the whole distance in feet, and the quotient may be substituted for I in the formulae above. That is, if x and y be its distances in feet from the two bearings respectively ; , _ Axy ~ i^+y) From these rules the strength of shafts may be calculated, in all the cases of ordinary practice, where the tendency to trans- verse fracture has to be guarded against, making the actual strength at least five to ten times the strain to be carried. In shafting, however, it is not usually the transverse rupture, but the flexure jsroduced by lateral stresiL which limits the size of the shaft; — stiffness in fact becomes, in these cases, a more important element than strength. The follomng formula has been given for the deflection of bars or beams loaded at the centre and supported at the ends : — Let, d be the depth in inches ; b the breadth in inches ; L the length between supports in feet ; W the load in lbs. ; S the deflection at the centre in inches : M the modulus of elasticity ; then : — w = . , ' ; and ii h = d, — 432 L^ ox THE STRENGTH AXD PROPORTIOXS OF SHAFTS. 55 fZ-* = 432l3w or d _ 4 / 432 l3 L^ W (4.) Or, in words, multiply the product of the load in Ihs., and the cube of the length in feet, by 432, and divide by the product of the modulus of elasticity and the deflection assumed in inches ; the fourth root of the quotient will be the side of a shaft of square section which would deflect S inches with a weight of W lbs. placed at its centre.* The follomnof table crives the values of the modulus of elas- ticity for various materials : — Modulus of elasticity in lbs. Cast-iron . „ „ mean Malleable iron Steel Brass Tin Ash Beech Eed pine, mean Spruce, mean Larch English oak American oak 13,000,000 to 22,907,000 17,000,000 24,000,000 to 29,000,000 29,000,000 to 42,000,000 8,930,000 4,608,000 1,600,000 1,353,600 1,700,000 1,600,000 900,000 to 1,360,000 1,200,000 to 1,750,000 2,150,000 For a cylindrical shaft, the same formula will apply witli another constant. I am not aware that this has been experi- mentally ascertained, but it has been given approximately as 734. Hence, for cylindrical shafts, ;, 734 l3 w cr = or d=^ V734l^w ...(5). M 6' ' M S In the work just quoted, these formulae have been simplified, by fixing a maximum value for d, the deflection. The writer assumes that, with shafting, the deflection ought never to exceed y^ of an inch for every foot length of the shaft. Sub- * Engineer and Machinist s Assistant, p. 135, from -which formulse (4), (5). (6), to (11), and (23), in their present conrenient form for practical use, have been quoted. The fundamental formula, however, is due to Young (Sat. Philos. toI. ii. art. 326), and to Tredgold (Strength of Cast Iron, p. 208). 5G ON MACHINERY OF TR.iNSMISSION. stitiiting this value, and also the numerical value of the modu- lus of elasticity, he obtains the following formulae : — 1. For wood, — taking M generally = 1,500,000, and S = inches. 100 Then, for square shafts, d being the depth of the side of the square — <^- = ^...(6). And for round shafts, d being the diameter in inches — 20 ^ ^ 2. For cast-iron — taking m = 18,000,000 lbs. and l as before — L^ W For square section, d* = — - ... (8). For round section, d^= ...(9.) ' 240 ^ ^ 3. For torought-iron — taking m = 24,500,000 lbs. and 8 as before — For square section, cZ'* = — — - ... (10). For round section, d*^ = ... (11). 334 ^ ^ By transposition, the formulae given above become, — For ivood — /35 c/* Square section, l = ^ ... (12) w 35f^4 w= — - y20 d'^ ... (13). w W= (14). For cast-iron ■ Square section, l = ^ — — - ... (15). w= lli^...(,6). ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 57 Eound section, l = »J ... (17). "W 240 f?^ .,o^ W= — ^ (18). For ivrought-iron — Square section, l = ^- ... (19) w= '-^...(20). Eound section, l = ^/ — ... (21). .=y?^...(22). \Mien the weight is uniformly distributed over the length of the shaft, the general formula is d^ = ^— or d = ^ — - ... (23). Substituting in this equation the same values of M and B as before, we obtain the following formulse : — L^ W For ivood— d* = — -^ for square shafts. 00 d* = -— — for round shafts. • L.^ W For cast-iron — d* = -— — for square shafts. 666 ^ T 2 xy d* = for round shafts. 383 For wrought-iron — d* = for square shafts. d* — for round shafts. 521 The following tables for cast and wrought-iron round shaft- ing, are calculated from the formulse (9) and (11) for weights placed at the centre of a shaft supported at each end. In using them for cases in which the weight is distributed along its length, as in the case of the weight of the shaft itself, it must be remembered that a distributed weight produces -|ths of the deflection of the same weight placed at the centre. I 58 ON MACHINERY OF TRANSMISSION. t^ CI 00 Ci CO ■*! t^ ^ -^ ^ !M Ci CO O a> C5 s ^^ ^_4 ,_) o pH t-~ CO CD a IM t^ o t~ <:> «3 o ^ CO ^ o a> o »-- CO I-H 00 00 o «o -* CO OO OO IM Ci ^ CO I^ t~ (M o oo >o CO C<) ^ CO i^ CD O o ^ o CO O 00 00 p-4 >o p-l r^ ■* p-i o> Ir^ c 00 o •* o 00 t^ «3 ■* •<*< CO CO !N IM -'3 CO J^ lO T»< I^ (M 00 >o oo ,-H o CO t— CO CD O CO o ^ CO (M (N '"' ^ ^ •"' — , — o o o O ■* t^ „ •o l^ ^ >o o — o o or; o CO O oo CO o -tl CO t^ O 2 2 ^ o o lO CO o 00 CO (M o -t*< CD o oo CI C5 t^ CO CO -* 1^ o C5 CO O Tt< 00 00 C3 CO CO OJ CO ^ C5 l^ CO »o -*l Tji OO !M t^ IM ^ o o ^ »-- t^ CD C7> o I-H -* oo 00 O) o O CO CO CO fN fN I-H r-H CO -* o CO oo >o oc oo CO o CO r-4 oo t-H 00 00 o CO 00 ^ o 1^ -f C3 I~ CO -* CO oo CO IM iM JZ CO Ol C-J »— * —J t:^ o -i< lO CO CO (M ^ J-J ,_, ^ ^ C5 o ^ >o o CO p-H CO CO o I-H -# CO >o o t^ -*< 2 t- X! o o l-^ o t— * t^ I^ o 'J' o lO c^ Oi t^ CO T(< n CO CO ,— 1 C3 t^ lO ^ ■^ CO (M . ^ CI 00 CO ■* CO CO (N (M 1-H I-H T-H r^ ^ s I— 1 B 'O o oj 1— ( I— ( CO >o »o o I-H CO on r> CO lO O X -*1 to CO CO p-H Cl f-H 01 03 (N t-- lO CO W5 Q o IN C5 oo t^ CO CD U3 CO CO ^ CO (N C<) —1 '-^ ■-H ^ o CD ^ -* d o o (M CO >o CO CO C3 __i CO >o iC to » CO CO ■T7< >o o ^ ■^ Cf3 CO CO rr> r^ IM t^ ^^ co~ CO of CO c^_^ p-T 00 l^ CO •o >o -* ■* OO t^ ^ 00 00 >o Tf ■>*< CO CO Ol t^ ^ ^ ^ t^ CD ■HfM to CO o CO l-H on no oo CO — H — co" >o^ <>J^ C3 00 CO lO >o ^ oo OO CO C<1 CO 00 t^ ^ o 00 la 00 r^ ^ _^ r^ _ CO (M 00 -* ■^ » lO o lO CO lO 1-^ ^ IM en rH t^ ^ ,-H CJ lO ~ of »-- c^^ a> t^ CO i-O -*< CO CO r>i • IM ^ o >o CO >o o 00 ■-I ~-. ^ o __^ lO IM r-. o 3?^ to -* o CO CD ^ CO c^ >-o I-H rn CD o ^ o_ t^ lO ^ CO (>4 (N (N '~* '"' '"' « GO — t-- -H o "* o 'O i-. CS C-O CO ^ ~v ^ 00 -* C5 o m CO CO r«i C5 on r^ CO CO lO -* lO CO CO 04 ■-1 '-< •-1 I-H 'O rt ^ CO o ^+1 t^ i-O CD on (M t^ oo a> CO oo cT J3 tf T-H o r- CO >o -^ ■* oo CO iM IM CO "" ■"I '-' '-' ^ r^ 00 ;^ I^ CO oi t^ CO Ci t^ "O CO OJ ,_ o a o r^ CO M< CO CO OJ IM f-^ '"' ■-^ -t^ to' C5 'f »o o >a ^1 o o CO t^ 00 05 o -J oi CO ^ »o CD b- 00 Ci o -.3 ox THE STEENGTn AND TKOPOIITIONS OF SHAFTS. 59 (M >o CO c» CO s o -* CO t^ CO 'O t-t h- CO I-H (M CO CO (M •^M •o o 00 t^ C5 CO C3 CO '^ IM o 05 00 t— o CO •* IM ^ -* o o ■* CO c^ >-o ■* t~- CD CI CO 1-H IM CO >o ^_, g CO '.•5 o -*< CO CO C2 co fN o Oi ,_( -^ en CO (M CO i-H ■* o 'O M ^ o t^ o CO »o •<*< ■* CO o •^ CO o •* c r^ ^ CO i-H C5 'O '3 CO cc l-^ o t^ t^ t^ t^ '" o us 00 CO CO oo 00 CO o CO !M C^I 00 lO CO (M o C5 00 t^ - - CO 00 '-0 ~ CO o CO ^ 'It* r^ CO o 00 CO 00 CO o o o CO --^ ^ ■^i^ lO CO •o o 91 !^ t-- »-H 1— < Ol ■^ CO P— 4 t^ o an o lO ■■*< ■* CO CO C5 CO ■^ CO CO (M CO Ci t^ -* CO ^ o C5 00 ^ rt ^ — CO CO O CO o — _ — -M ^ o 00 t^ ■* r— ( f— t f-H CO oo -^ o 00 00 2 o 00 t^ o i-O 00 't' ^ 00 LO (M C5 00 t^ CO CO >o CO ■^ CO •M •M 1—4 ^H t-H i-H TTl CO o CO O ^ CO o >o — — ^ ■* CO CO o a « Co (M 30 ^ t^ o C2 CO CO CO CO o o C5 ^ CO t^ IM QO ■* c c ou t-- CO CO C2 00 CO o lO ■* ■* CO CO >o CO C<1 "N I— ( I-H »-H CO r— t^ rt — ^ 00 05 lO ^ -m CO >o 00 ^ lO J, tn t^ t^ CO CO o o IM o c^ CO o -* -* CO CO r-l IM f— t (M CO CO •^ o IN 00 5 CO O QO t^ CO CO «3 o lO (M o CO ■* CO IM o t^ 00 CO lO ■* CO CO Cl O CO CO r^ 00 fM i-O CO CO Co 00 o o t^ -*< iM o C5 00 t^ CO >o lO 00 >o ^ CO Co o ^_, — iM (M o Ci Ci «-o ,^ ^ o 05 *«* OQ r^ o d rfi C5 t^ CO »o o ^, CO I^ CO 00 - co" (n" o_ CO t-T a> 00 o CO >o ^ 'tl CO CO o >o lO CO o »o (^ •^ l^ CO o ^ CO on o CO T, oc (N l^ ■^ CO >o u-^ o o o CO 00 CO a CO -* '^ CO t^ CO o 00 t^ lO o ^ CO CO IM iM (M Oi CO c^ ^ — ' '-< >o i o r~ >o 'if t^ 'O CO O) £ C 00 no t~ »o CO ^ h- •* iM o 1 I 1 1 I 1 1 CO ■* CO (N IM ^ ^ '^ 1 1 1 ' 1 1 1 •* CO 00 C CO «3 1 1 1 1 1 1 1 1 1 _ '_ ' 1 - c mU 5 s »o o t^ 00 CI O t-H (N CO ■* lO CO t^ 00 C5 o .31 60 ON MACHINERY OF TRANSMISSION. From the foregoing it will be seen, that the weights given in the tables are correct indications of the load required in the centre to produce a deflection of the y^Vo of the length of the shaft.* This fraction is not however the universal standard among millwrights ; on the contrary, there appears to be no recognised standard in practice, by which the deflection from a given weight can be ascertained, and although -^-^q^ may, in many cases, give a larger area with increased weight, in shafts that are not heavily loaded in the middle, nevertheless it is important that the shafts, when loaded as above, should not bend more than ^j-^ ^^ ^^^^^ length. In cases where the load is light and equally distributed, lighter and smaller shafts would suffice. The following tables give the deflection of cylindrical shafts with their own weight: — Table 3. — Deflection aeising feom the Weight of the Shaft. Cast-Ihon Cylindeical Shafts. Length be- tween bearings in feet. Diameter of Shaft n Inches 1 2 4 G 8 10 12 14 16 ins. ins. ins. ins. ins. ins. ins. ins. ins. 5 •004 •001 •000 •000 •000 •000 •000 •000 •000 10 •067 •017 •004 •002 •001 •001 ■001 •000 •000 15 •338 •085 •021 •009 •005 •003 •002 •002 •001 20 ro67 •267 •067 •029 •017 •Oil •007 •005 •004 25 2-603 •651 •163 •073 •041 •026 •018 •013 •010 Table 4. — Deflection aeising feom the Weight of the Shaft. Weought-Ieon Cylindeical Shafts. Length be- tween bearings in feet. Diameter of Shaft in Inches. 1 2 4 6 8 10 12 14 16 5 ins. •003 ins. •001 ins. •000 ins. •000 ins. •000 ins. ■000 ins. •000 ins. -000 ins. •000 10 •050 •013 •003 •001 •001 •001 •000 •000 •000 15 •256 •064 •016 •007 •004 •003 •002 •001 •001 20 •808 •202 •051 •022 ■013 •008 •005 •004 •003 25 1-972 •493 •123 •055 ■031 •020 •013 •010 ■008 The above tables clearly indicate the deflection of shafts of different lengths by their own weight, and will be a guide to the * Tliis standard is the one assumed by Tredgold (Strength of Cast Iron, p. 210). I Oi\ THE STRENGTH AND TEOPORTIONS OF SHAFTS. 61 millwright in calculating the distance of the bearings between which they revolve. It is important in shafting, when extended in long ranges, that there should not be any serious deflection, either from the weight of the shaft, or lateral stress ; I have always found that a stiff shaft, although heavier in itself, is lighter to retain in motion than a smaller one which bends to the strain. 3. Torsion. In addition to the lateral flexure from transverse forces, shafting is subjected to a wrenching or twisting, from the power transmitted acting tangentially to its circumference. This causes one end of the shaft to revolve in relation to the other end, through a smaller or greater angle, known as the angle of torsion, and, if sufficient force be applied, this angle increases till the resistance of the material is overcome, and the shaft gives way. Coulomb laid the basis of our knowledge of the resistance to torsion of cylindrical bodies, and he verified his theoretical de- ductions by admirably-contrived experiments, on a small scale. He showed that in wires where the diameter is small in relation to the length, the angles of torsion are in proportion to the length, and reciprocally proportional to the moment of inertia of the base of the cylinder in relation to its centre. He also discovered that each wire acquired a permanently acceleration- varying torsion, according to the degree in which it departed from its primitive position, and that these permanent torsions have no fixed relation to the temporary torsions, coexisting with the application of the moving force. With the same wire he found the torsion to be in proportion to the force applied ; with the same length and force inversely as the fourth power of the diameter. These deductions are expressed by the following formula : — 2r w^ 6 = X — r ttG t* where 6 is the angle of torsion, r the radius, and I the length of the wire, R the leverage at which the weight W acts, and G the modulus of torsion for the material; being about fths of the modulus of elasticity. 62 ON MACHINERY OF TRANSMISSION. In 1829 a paper was communicated to the Royal Society by- Mr. Bevan, containing experimental determinations of the mo- dulus of torsion for a large number of substances, of which the most important are given below. Let 8 be the deflection of a prismatic shaft of a given length I when strained by a given force iv in lbs., acting at right angles to the axes of the prism and at a leverage r ; let d be the side of the square section of the shaft, I, r, S, d, being in inches. -, r'^ hv d*T where t is the modulus of elasticity in the following table. If the transverse section of the prism be a parallelogram, let b be the breadth and d the depth, then Mr. Bevan gives the formula — _ (d + b) IrHu 2bdH If the torsion be required in degrees (A), then let p = 57-29578, I For example. A = , for square shafts. A rlw . ^ . , , ~ " 'ji<\n<\ ,, - lor wrought-irou and steel. '61000 d^ rlw for cast-iron. 16600 f^^ A very careful experimental study of the effect of torsion on various materials has been made by Mr. M. G-. Wertheim, and was presented to the Academic des Sciences in 1855. The general results at which he has arrived may be stated as follows : — 1. The total angle of torsion consists of two parts, of which one is purely temporary, whilst the other persists after the force has ceased to act. It is not possible to assign the limit at which the permanent torsion begins to be sensible, nor has it any fixed relation to the temporary torsion; it augments at first very slowl}^, afterwards more rapidly, till the bar breaks.* * We liuve many practical instances of this tendency to raptiu-e which at first appear only temporary, but a continuation of the same action, particularly in long ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 63 T.1BLE 5. — Vaxues of M0DU1.US OF ToEsioN AccoRDmo TO Mb. Bev.vn. Material. Specific Modulus of torsion. gravity (T). lb.c. Ash . . . . — 20,300 Beech . . . . 21,243 Elm . . . . 13,500 Scotch fir ... 13,700 Hornbeam •86 26.400 Larch .... •58 18.967 English oak — 20,000 Memel jjine — . 15,000 American pine — 14,750 Teak . . . . — 16.800 Old and partially decayed. Teak, African . — 27,300 Iron, English wrought — 1,775,000 (Mean.) ■Steel — 1,753,000 (Mean.) Iron (cylindrical) — 1,910,000 » ,, . . . — 1,700,000 „ (square) . — 1,617,000 J) » ... — 1,667,000 — 1,951,000 Cast-iron _^ 940,000 963.000 ,, ,, ... — 952,000 ,, ,, ... — 951.600 (Mean.) Bell metal — 818,000 2. The temporary angles are not rigorously proportional to the moments of the forces applied. 3. The mean angles of torsion are not rigorously proportional to the length of the bar, increasing, although very slightly, in proportion to the length, as the bars are made shorter. 4. The interior cavity of all hollow homogeneous bodies di- minish by torsion, and this diminution is proportional to the ranges of shafts, in process of time, developes itself in the form of a permanent deterioration which ultimately leads to fracture. This was strikingly exemplified in a range of shafts, 220 feet long, tapering from three inches diameter at the driving end, to two inches diameter at the other. The work done by these shafts was uniform throughout, but it was soon found that the shaft had made nearly 1^16 revolutions at the driven end of the room, before it began to move at the other. The result was a continued series of jerks or accelerated and retarded motion, injiirious to the machinery, and destructive to the work it had to perform. It was, moreover, injurious to the shafts, particulai'ly in the middle, where the twist was severely felt, and would have led to rupture, but from the circumstance that thej- hud to be renewed with a stifter and stronger range. 64 ON MACHINERY OF TRANSMISSION. length and to the square of the angle of torsion for unity of length. 5. For cylindrical bodies Mr. Wertheim gives the following formulae : — Let i/r be the mean temporary angle of torsion, for p = 1 kilogramme, and ^ = 1 metre ; jp — the sum * of the two weights producing torsion and constituting a couple in kilogrammes ; E = the leverage at which the weight jp acts ; I = length of the bar subject to torsion, in milli- metres ; r = the exterior radius of the section of the bar, in millimetres ; r, = the interior radius of hollow bars, in millimetres; E = the modulus of elasticity of the material ob- tained from experiments on tension. Then, for solid bars: — f 16 , 180 . i9R . I ' 1^ 3 TT^ E and for hollow cylinders 16 180 pn 11^ = I 3 it'- e r^—r^ In the following experiments, ^^ = 1 kilogramme, R = 247*5 millimetres, 1= 1000 millimetres. Resume of ExPEEniEXTS on Ctlxxders of Cercui-Ah Section. - Material. Radius r. Coefficient of elasti- city, E. MeaQ angle of torsion. By formula. By experiment. 1 2 3 4 5 6 Iron .... Iron .... Cast-steel . Copper Glass .... Glass. mm. 8-220 5-501 5-055 5-031 3-535 3-4225 17,805 19,542 9,395 6,200 17 46-1 1 28 0-8 1 53 12-0 3 59 59-1 24 51 56-0 28 18 2-0 17 52-1 1 26 31-3 1 51 13-4 3 54 6-0 24 15 34-7 28 30 14-0 * In Mr. Wertheiin's experiments equal -weights, acting in opposite directions at the same leverage were hung one on each side of the bar, subjected to torsion. t The above formiilse -may be used -with English measures, e being taken from English tables, if p be given in lbs. and r, l, and n in inches. ON THE STKEXGTH AND PROPORTIONS OF SHAFTS. 65 Resume of Expehiieents ox the Toesiov of hollo^v Cyiindees of Copper. External radius (r). Internal radius (ri). Coefficient of elasticity from tension (E). Angle of torsion (-4'). 1 By formula. By experiment. 53 54 55 7 8 9 11,525 7,082 5,047 5,602 45,605 36,955 10,021 4,955 30,315 24,665 2,478 2,471 10,917 10,444 10,276 9,665 9,855 10,645 O / II 17 30-2 1 12 18-3 4 9 4-0 2 37 40-4 6 11 10-3 15 9 14-4 O / // 20 0-6 1 16 52-9 4 6 54-7 2 33 38-2 6 53-8 15 42 37-3 The accordance, in these tables, between the formulae and the experiments is very satisfactory, especially considering that the value of E cannot be determined with perfect accuracy. The errors do not generally exceed g^th, and the observed angles are smaller than those found by calculation, except in the case of the cylinders 9, 53, and 5-4. For bars of elliptical section M. Wertheim has deduced the formula 8^ ^ 180 _pii ^ l{c\-^cX) 3 TT^ E C^Cl r" Q _2 where c^ and c„ are the two semiaxes of the ellipse, the other letters remaininsf as before. Resume of Expeetsients on the Toesion of Eixbpticai Baes. Material. Semiaxes. CoeflScient of elasticity Mean angle of torsion (■4-). C\. Cj. by tension (E). By formula. By experiment. 11 12 13 14 Cast steel . . Copper . . . mm. 7,105 9,900 7,062 9,875 mm. 1 3,697; 19,085 25,075 3,669. 9,634 2,498j 2 13 56-7 4 18 01 4 32 56-7 8 38 11-2 2 10 55-4 4 13 18-2 4 30 41-2 8 54 33-9 For bars of rectangular section the formula becomes "ylr = 180 \ 'p^ ^ l{cC^ + })'') But it is necessary to apply a coefficient of correction c to the VOL. II. F G6 ON MACHINEEY OF TRANSMISSION. calculated angle such that if ^/^i be the calculated angle of tor- sion, and i/r^ the angle found by experiment, then c = -j — . This coefficient varies with the ratio r of the sides of the bar ; thus, when I = 500 millim^treSj and the section was 36 millimetres square. a -r- 1 2 4 8 Value of coefficient 0-8971 0-9617 0-9520 0-9878 It varies also with the ratio -r- and with the moment of the couple p R. For the ultimate resistance of cylindrical shafts to rupture by torsion, Professor W. J. M. Kankine gives the following formula : * Let I denote the length in inches of the lever, such as a crank, at the end of which a wrenching or twisting force is applied to an axle. Let w be the working load in pounds, multiplied by a suitable factor of safety (usually six) ; then W? = M is the wrenching moment in inch pounds. For a solid axle let h be its diameter : then /'' For a hollow axle let h^ be the external, and JIq the internal diameter in inches : then fi^t-ht) _fhi f._hL^ 5-lh^ ~ 5-1 • V hf J M 0-1/? J 5-1 5-1 M and 7ij = [/(-I) The values of the modulus of wrenching / are — for cast iron about 30000, for wrought iron „ 54000, * Manual of Applied Mechanics, p. 355. Manual of Steam Engine, p. 78. ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 67 and taking six as the factor of safety, if we put the working moment of torsion in the formulaB instead of the wrenching moment, we may put instead of / for cast iron . . . . 5000, for \vi-ought iron . . . 9000. Hence we get for w, the working stress, with solid shafts, 5000 h^ 980 /t3 Wi = — - , = J — lor cast iron • • • \^-) 9000/^3 ..„^,. ^ , . , , , = - , = — -J — tor -wrought iron. . . (o.) On this principle I have calculated the following tables (pages 68, 69), giving the safe moment of torsion for cylindrical cast and wrought iron shafts, and also the working stress to which they may be subjected at the circumference of pullies or wheels of various diameters. In cases where the horses' power trans- mitted by a shaft is given instead of the stress, the latter may be found by the table on page 47. The greatest angle of torsion, which it is safe to allow in a line of shafting, is determined by the extension of the material within the elastic limits. If Yi^Q-^ih. of the length be assumed as the maximum extension with the safe working load, then the shaft must be so proportioned that the angle of torsion is less than that given by the following formula 2284 L . ^=1000^ (4-) where L is the length of the shaft in feet, d its diameter in inches, and y^ the angle of torsion in degrees. It is convenient to estimate the ultimate resistance of shafts to torsion, not only as a statical pressure acting at a leverage, but also in horses' power. Now the stress resulting from the transmission of power must evidently increase in proportion to the power, and decrease in proportion to the velocity. A shaft will transmit 100 horses' power at 80 revolutions a minute with no more stress than it would transmit 50 horses' power at 40 revolutions, or 25 horses' power at 20 revolutions. Hence the F 2 68 ON MACHINERY OF TRANSMISSION. rHlOCO'C'+O-^aO'tli— l!MOOOG5CDOOi— li— ICO'*COOCO'^(MCCOt^'— I i-H C^^ ■* t^ O -* O l^ "O ■* CD 00 CO O CD 0_ CO t-- COCOC3i— I (^)t-»oocDcooo5i>ir-ia3-*i— (o-^'ocoi— ii— icocococo>oaOi— iQO-^OGO I— ICOOO-*"— l0500O-*O00C3C0OOC0OC0iMOt^C0C0i— li— (00 i-T 1— r co' ciT oo" cT r-^ -^ t-^ cf co i— T o" r-^ ■*" co' lo' ■>*<' co O cd' 1— li-lrH(M(MCO^U5COt^a5t-ICOCOOO (MOr-lO. 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CO CO 00 Oi iM OO -* 'O C7» t~- -IH CO oo 00 lO o »o t^ f— t ^ CD CO CO tX) CO co 05 -* oo M CD o 1 1 1 1 (M IM CO CO CO 'i' IC lO o !>• t^ 00 00 C5 O o (M 00 '^i M< o O ^ a O CO CO CO o 'b op CO Ol 1^ 05 ' ' ' ' ! ' ' ' ' ' ■a i! S z >.S i-H -N eo Tt< >o o >Cl o o O o o o o o o o o c^ o " S 'Ss I-H (N CO ■* lO CO l^ 1— ( ^" £ 72 ON MACIIINEEY OF TEANSMISSION. 4. Velocity of Shafts. As the quality of the material employed for the construction of shafts enters largely into" the calculation of their strength, so also the velocity at which they revolve becomes an important element in the calculation of the work transmitted by them. In all cases where machinery has to be driven at a high speed, it is advantageous and even essential to run the shafting at a proportionate velocity. If, for example, there are a series of machines running at 500 revolutions per minute, it will be ad- visable to run the shafts at half that speed, by which means the following very important advantages will be gained. There will be a great saving in the weight of the shafts, for with a slow motion of 50 revolutions per minute, fully three tivnes the weight would be necessary to transmit the same power. There would also be a saving in original cost in the power absorbed, and in maintenance. Shafts running at low velocities are cumbersome, heavy, and expensive to repair. They are costly in the first instance, and they block up the rooms of the mill with large drums and pullies, obstructing the light, which, in factories, is a considera- tion of very great importance. At the commencement of the present century mills were geared with ponderous shafts, such as those just described. They were generally of cast iron, square, and badly coupled, and the power required to keep them in motion was in some cases almost equal to that required by the machinery they had to drive. In the present improved system, with light shafts accurately fitted and running at high velocities, the work which previously was absorbed in transmission is now conveyed to the machinery of the mill. I may safely ascribe my own success in life and that of my friend and late partner, Mr. James Lillie, to the saving of power effected by increasing threefold the velocity of the shafting in mills more than forty years ago. The introduction of light iron shafting not only enabled the manufacturer to effect a consider- able saving in the original cost, but a still greater saving was ON THE STRENGTH AND TROPORTIONS OF SHAFTS. 73 effected in power, whilst it relieved the mills from the ponderous wooden drums and heavy shafting then in use, and established an entirely new system of operations in the machinery of transmission. 5. Length of Journals* Another consideration of considerable importance to the smooth and safe working of shafting is the length of the journals. From a number of years' experience I have been led to believe, that with cast iron, one and a half times the diameter of the shaft is the best proportion for the length of the bearing, and with wrought iron, one and three quarters the diameter. On the question of shafts revolving in the steps of plummer blocks and the proportions necessary to effect motion without danger of heating, it is essential (mthout entering largely into the laws of friction on bodies in contact) that we should ascertain from actual practice and long-tried experience the best form of journals of shafts adapted for that purpose. The lengths proportionate to the diameters have already been given, but we have yet to con- sider the dimensions of the journals of large shafts where they are small in comparison with the pressure or the weight they have to sustain. Let us, for example, take a fly-wheel shaft and the foot or toe of a line of vertical shaft extendinsf to a height of six or seven stories in a mill filled with machinery, and we have the safe working pressiu-e per square inch as indicated in the last column in the folio wing: table : — DescriptiOQ of Shaft. Length and diameter of Shaft in ins. Number of square inches in bearing. Weight on bearing in lbs. Weight in lbs per square inch on bear- ing. Fly-wheel shaft -nronght iron Vertical shaft cast iron Horizontal shaft cast iron Horizontal shaft wrought iron Ditto ditto ditto . 18 X 14 - X 11 15 X 10 6x3 2x4 252 95 150 18 8 45,024 23.061 6,000 540 160 178-21 242-70 40-00 30-00 20-00 From the above it will be seen that in fly-wheel shafts the * Rules for the diameters of gudgeons or journals for those cases in which thej- are calculated independently of the diameter of the shaft, are given in Mills and Millwork, vol. i. p. 116. 74 ON MACHINERY OF TRANSMISSION. pressure should never excee'd 180 lbs. per square inch, and in that of the toes of vertical shafts 240 lbs. per square inch. Even with this latter pressure it is difficult to keep the shafts cool, and it requires the greatest possible care to keep them free from dust or any minute particles of sand or other sharp sub- stances getting into the steps. The feet of vertical shafts also require the very best quality of gun metal for the shaft to run in, and fine limpid oil for lubrication to prevent the toe from cutting. It is, moreover, necessary for the shaft to fit well on the bottom of the step, and not too tight on the sides, and to have a fine polish. p-„ 206. Another point for consideration is „ a the proper form of the journals of shafts, and that is, they should never have the journal turned or cut square " " down to the diameter, but hollowed in the form shown in the figure at a a a a. From a series of interesting experiments it has been shown that the square-cut shaft loses nearly -^ of its strength, and by simply curving out the shaft at the collars in the form described, the resistance to strain is increased J- or in that proportion. 6. Friction. On the subject of friction much cannot be said. We may, however, adduce a few experiments from Morin and Riviere, which appear to bear out our previous experience of the length of journals. In the years 1831, 1832, and 1833, a very extensive set of experiments were made at Metz by M. Morin, under the sanc- tion of the French Government, to determine, as nearly as pos- sible, the laws of friction, and by which the following were fully established : — When no unguent is interposed, the friction of any two sur- faces, whether of quiescence or of motion, is directly propor- tional to the force with which they are pressed perpendicularly together ; so that for any two given surfaces of contact there is a constant ratio of the friction to the perpendicular pressure of the one surface upon the other. Whilst this ratio is thus the same for the same surfaces of contact, it is different for different ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 75 surfaces of contact. The particular value of it in respect to any two given surfaces of contact, is called the coefficient of friction in respect to those surfaces. When no unguent is interposed, the amount of the friction is, in every case, wholly independent of the extent of the sur- faces of contact ; so that the force with which two surfaces are pressed together, being the same, their friction is the same, whatever be the extent of their surfaces of contact. That the friction of motion is wholly independent of the velocity of the motion. That where unguents are interposed, the coefScient of friction depends upon the nature of the unguent, and upon the greater or less abundance of the supply. In resjject to the supply of the unguent, there are two extreme cases, — that in which the surfaces of contact are but slightly rubbed with the unctuous matter, as, for instance, with an oiled or greasy cloth, and that in which a continuous stratum of unguent remains continually in- terposed between the moving surfaces ; and in this state the amount of friction is found to be dependent rather upon the nature of the unguent than upon that of the surfaces of contact. ]M. Morin found that with unguents (hog's lard and olive oil) interposed in a continuous stratum between surfaces of wood on metal, wood on wood, and metal on metal, when in motion, have all of them very nearly the same coefficient of friction, being in all cases included between '07 and '08. The coefficient for the unguent tallow is the same, except in that of metals upon metals. This unguent appears to be less suited for metallic sur- faces than the others, and gives for the mean value of its coefficient under the same circumstances 'lO. Hence it is evi- dent that where the extent of the surface sustaining a given pressure is so great as to make the pressure less than that which corresponds to a state of perfect separation, this greater extent of surface tends to increase the friction by reason of that adhe- siveness of the unguent, dependent upon its greater or less vis- cosity, whose effect is proportional to the extent of the surfaces Ijetween which it is interposed. Mr. G". Eennie found, from a mean of exj^eriments with differ- ent unguents on axles in motion, and under different pressures, tliat with the unguent tallow, under a pressure of from 1 to 76 ON MACHINERY OF TRANSMISSION. 5 cwt., the friction did not exceed Jg^th of the whole pres- sure ; when soft soap was applied it became -g^th ; and with the softer unguents applied, such as oil, hog's lard, &c., the ratio of the friction to the pressure increased ; but with the harder un- guents, as soft soap, tallow, and anti-attrition composition, the friction considerably diminished : consequently, to secure effec- tive lubrication, the nature of the unguent must be accom- modated to the pressure or weight tending to force the surfaces tosfether. Table of Coefficients of Fbictiox under Peessubes inceeased continually rp to Limits of Abeasion. By Me. G. Eennie. CoeflScients of Friction. Pressures per Square Inch. Wrought Iron upon Wrought Iron Steel upon Cast Brass upon Cast Wrought Iron. upon Cast Iron. Iron. Iron. 32-0 lbs. •140 •174 •166 •157 1-66 cwts. •250 •275 •300 •225 2-00 „ •271 •292 •333 •219 2-33 „ •285 •321 •340 ■214 2-66 „ •297 •329 •344 •211 3-00 „ •312 •333 •347 •215 3-33 „ ■350 •351 •351 •206 3-66 „ •376 •353 •353 ■205 4-00 „ •395 •3G5 •354 •208 4-33 „ •403 •366 •356 •221 4-66 „ •409 •366 •357 •223 500 „ — •367 •358 ■233 5-33 „ — •367 •359 •234 5-66 „ — •367 •367 •235 6-00 „ — •376 •403 ■233 6-33 „ — •434 •234 6-66 „ — _ ■235 7-00 „ •232 7-33 „ — — — •273 From a paper lately read at the Institution of Civil Engineers in London, on the comparative friction of steam engines of different modifications, it appears that, as respects the friction caused by the strain, if the beam engine be taken as the stand- ard of comparison — The vibrating engine . . has a gain of 1-1 per cent. The direct engine with slides „ loss of 1*8 „ Ditto with rollers . . „ gain of 0-8 „ Ditto with a parallel motion „ gain of 1 -3 „ ON THE STRENGTH AND PROPORTIONS OF SHAFTS. 77 It also states, as an opinion, that excessive allowance for fric- tion has hitherto been made in calculating the effective power of engines in general ; as it is found practically by experiments with the engines at the Blackwall Eailway, and also with other engines, that where the pressure upon the piston is about 12 lbs. per square inch, the friction does not amount to more than l^lbs. ; and also that by experiments with an indicator on an engine of 50 horse-power, at Truman, Hanbury, and Co.'s brewery, the whole amount of friction did not exceed 5 horse- power, or i^th of the whole power of the engine. 7. Lubrication. On this question it is necessary to observe that the durability of shafts, and their easy working, depends on the way in which they are lubricated, and the description of unguent used for that purpose. We have already seen the difference which exists in the coefficient of friction from the use of different kinds of unguents, and we have now to consider what system of lubrica- tion should be adopted to lessen the friction and maintain smooth surfaces on the journals of shafts. In large cotton mills I have known as much as ten to fifteen horses'-power absorbed by a change in the quality of the oil used for lubrica- tion ; and in cold weather, or when the temperature of the mill is much reduced (as is generally the case when standing over Sunday), the power required on a Monday morning is invariably greater than at any other time during the week. It is, therefore, necessary in most mills — particularly those employed in textile manufacture — to retain a uniform tempera- ture, and to employ the best quality of oil for lubricating the machinery, as well as the shafts of the mill. The best lubricators are pure sperm and olive oils ; they should be clean and limpid, and sparingly applied, as it is a profligate waste of valuable material to pour, as is not unfre- quently done, large quantities of oil on the bearings, nine-tenths of which run on to the floor, and cover the shafts and hangers with a coat of glutinous matter, that soon hardens, and accumu- lates nothing but filth. This process of oiling shafts is generally left to the most negligent and most untidy person in the establishment; and 78 ON MACHINERY OF TRANSMISSION. the result is, that every opening for the oil to get to the bearings is plugged up, the brass steps are cut by abrasion, and the necks or journals of the shafts destroyed. In the best regulated establishments this is' certainly not the case, as the greatest possible care is observed in selecting the best kinds of oil, and that used with attention to cleanliness and strict economy in its application. To save power and effect economy in the use of lubricants, several schemes have been adopted for attaining a continuous Fig. 207. system of lubrication. None of them a\z=^;^ ' appears to answer so well as that which ^^iljiiiili!, [I ^j.^ consists of a small cistern, a, fig. 207, ^^B ; , J which contains a quantity of oil, and is liliiiiiiiiiilililiiilllll fixed on the top of the plummer block. In the centre of the cistern is a tube, which stands a little above the level of the oil ; and into this is inserted a woollen thread, with its end descending a short distance below the surface of the oil in the cistern ; and when properly saturated, the oil rises by capillary attraction, and flows gently, in very minute quantities, on to the neck of the shaft. From this description it will be seen that the quantity used can be regulated to the greatest nicety, and sufficient to lubricate the bearings without waste. Other plans have been devised for the same object, but none of them seems to answer so well as that just described. COUPLINGS AND DISENGAGING GEAR. 79 CHAPTER III. ON COUPLINGS FOR SHAFTS AND ENGAGING AND DISENGAGING GEAR. In eveiy description of mill where the machinery is spread over a large area, and at a distance from the moving power, it is necessary to have long lines of shafting, revolving at the required velocity. Such lines are seldom made in one piece ; short lengths must, therefore, be coupled together, so as to form an unbroken line, extending, in most cases, the whole length of the mill. When cast-iron shafts were substituted for wood, a square coupling-box, made in one piece, was generally used, so as to slide over the two ends of the shafts, or in two pieces, bolted together, as shown in figs. 208 and 209. Fig. 208. In the former case the box was slipped on loose, and the adjustment was so imperfect that the shafts rose and fell in the box at every revolution, destroying gradually any accuracy of fitting which, in the first instance, had been attained. Fig. 209. After the square-box coupling came the claw, or two-pronged coupling, made in two parts, wedged, but more frequently keyed 80 ON MACHINERY OF TRANSMISSION. on to the ends of- the shafts, as shown in fig. 210. This was a great improvement, as the leverage of the bearing parts was greatly increased, and the coupling, in consequence, became more durable. A description of half-lap coupling was introduced by the late Mr. Hewes. It was formed by the lapping over a part of the end of each shaft, which was cast square. A square box was also fitted over the two ends, so as to bind them together, and three keys were inserted on the top side, as shown in fig. 211. Fio-. 211. The objections to this coupling were the difficulty of fitting and the loosening of the keys, which made a creaking noise with every revolution of the shaft. Another coupling, still in use, is the disc. It consists of two discs or flanches, one on the end of each shaft, bolted together by four bolts, as shown in fig. 212. This coupling . 212. ON COUPLINGS. 81 was superior to all the preceding, when ptoperly bored and turned, so as to have its faces accurately perpendicular to the shafting. The best coupling for general purposes, and the most accurate and durable, is the circular half-lap coupling, introduced into my own works nearly forty years ago. It is perfectly round, and con- sists of two laps, turned to a gauge, and, when put together by a cutting machine, it forms a complete cylinder, as shown in fig. 213. A cylindrical box is fitted over these, and fixed by a Fisr. 213. key, grooved half into the box and half into the shaft. The whole is then turned in the lathe to the same centres as the bearings of the shaft, and by this process a degree of accuracy is attained which cannot be surpassed, nor is any other coupling so neat and so well adapted for the transmission of power. The proportions of this coupling are found by experiment to be — Twice the area of the shaft is the area of the coupling. The length of the lap is the diameter of the shaft. And the length of the box is twice the diameter of the shaft. These proportions have been found in practice to answer every purpose, both as regards strength and the wear and tear of the joints. There is another cou- pling which has come of late years ex- tensively into use, namely, the cylindrical coupling, with butt ends. It has the same VOL. II. Fig. 214. 82 OX J»rACIIINERY OF TRANSMISSION. proportions as the former, but not so strong nor so durable as the half-lap coupling of the same dimensions, as the entii-e force of torsion is transmitted through the key; but in cases where strength is not the chief object, it forms a cheap and effective coupling. 8. Disengaging and re-engaging Gear. This is an important branch of mill-work, requiring careful consideration and the utmost exactitude of construction when ponderous machinery has to be started, without endangering the shafts and wheels. This is most strikingly exemplified in the case of powder mills, where trains of edge stones are employed for grinding the gunpowder, and in rolling and callendering machinery, which requires well-fitted friction- clutches to communicate the motion by a slow and progressive acceleration from a state of rest to the required velocity. It used to be customary in cotton and silk mills to place disengaging clutches at the point of connection of the upright or driving shaft and the main shafting of each room, so that, in case of accident, a room full of machinery could be thrown out of gear at once. But these provisions were found unsteady in practice, and rather tended to increase than to diminish the number of accidents, owing chiefl}" to the time lost in dis- engaging, and the breakages which occurred in attempting to place the machinery in gear again, when the engine was running at full speed. It has, consequently, been found safer to have a permanent connection between the main lines of shafting throughout the mill, and signals from each room into the engine- house, in case of accident. When the construction of mill gearing was less perfect than it is at present, the main shaft driving the machinery in a room was thrown out of gear by a lever, which contained the steps, and supported the end of the horizontal shaft and wheel, which geared into that on the upright shaft, as shown in fig. 215, with a rope at the end of the lever a to pull it out of gear. This mode of disengaging wheels was very ineffective, as in many mills there are three bevel wheels gearing into that on the upright b, and it becomes complicated and dangerous to have ox ENGAGIXG AND DISEXGAGIXG GEAB. 83 Fig. 21 •J. movable levers to each. To remedy these defects, standards or plummer-blocks, with a m.ovable slide e, fig. 216, in which the end of the shaft revolved, was introduced. To the top Fiar. 216. ON MACHINERY OF TRANSMISSION. of this slide was attached a lever a, with a handle b, by which it could be drawn out of gear ; and the link c, falling along with the lever, retained the shaft out of gear until the mill was stopped. All these contrivances were, however, found inoperative on a large scale, as the shafts and wheels got out of order ; and it was ultimately found essentially necessary to make them stationary, by screwing the plummer-block down to the frame which con- nects the shafts and ^ F^g- 217. wheels. a Several devices have ' been employed for the purpose of rapidly en- gaging and disengaging machines from the driv- " 1 ing shaft. The best of all are the fast and loose pulleys, with a travelling strap. Thus, in fig. 217, a is the driving shaft, acting upon two pulleys e and d, fixed on the driving spindle of the machine b ; one of them, d, is keyed fast, and the other runs loose. When the machine is at work the strap is on the fast pulley d, and when it is necessary to stop, it is moved by a forked lever on to the loose pulley e, which revolves with the strap without acting on the machine. The machine is thrown into gear with equal ease by moving the strap on to the fast pulley d. Once on either of the pulleys, the strap is held in position without any danger of moving by the slight curvature of the pulley, as already explained. The forked lever must act on that side of the strap which runs towards the pulleys, and not on that which leaves them. A second and equally effective process for starting or stopping machinery is shown in fig. 218. A leather strap is hung loosely over the driving and driven pulleys a and 6, so that, left to itself, the friction is not sufficient to communicate motion to the ox ENGAGING AXD DISENGAGING GEAR. Fig. 218. 85 Fiff. 219. pulley on the shaft h; but a tightening' pulley fixed on a suitable lever e is forced against it by pulling the rope c, which bends the strap tightly upon the pulley b, and gives motion to the machine. This arrangement is in general use for sack teagles in corn mills, and for some other purposes. The same effect is sometimes produced by the sack teagles being fixed on the lever, and, by raising one end, the strap is tightened, and the barrel which raises the load is caused to revolve. The clutch most in use for throwing into gear heavy cal- lendering ma- chines is a clip friction hoop, which consists 86 OX MACHINERY OF TRANSMISSION. of a sliding box a, with two projecting horns on the driving shaft h. These horns, when slid forward by a lever (/, working in the groove c, come in contact with the friction hoop d, which embraces a groove in a second box, keyed upon the shaft of the machine. The instant the machine receives the shock of engagement, the clip d slides in its groove, until the friction overcomes the resistance, and the callender attains the speed of the driving shaft. The object of the friction clip is to reduce the shock of throwing the clutch suddenly into gear, as with- out this precaution any attempt to move instantaneously a powerful machine from a state of rest to a state of motion would break it in pieces. Friction cones are also much used for this purpose, and when carefully executed "with the proper angle are safer than the clutch just described. The objection to the friction clutch is, that the Avhole driving j^ower is throw^n on the clip at once ; whereas, with the cones, the parts can be brought into contact with the greatest nicety, and the friction regularly increased to any degree of pressure. Fig. 220 shows this description of disen- Fig. 220. gaging gear : a is the male sliding cone, worked by a lever in the usual way, 6 the female cone, keyed on the driven shaft, and the two surfaces, when brought into contact, communicate the required motion with perfect safety. Machines driven by friction, and requiring to be frequently ON ENGAGING AND DISENGAGING GEAR. 87 Fig. 221. stopped, are very numerous. Some of the lighter description are driven by a vertical shaft, b, fig. 221, supjiorting a horizontal disc, which communicates motion to the wheel a, rolling on its surface, and gives the necessary motion to the machine. The advantage ' of this friction-wheel is, that the velocity of the machine may be in- creased or diminished at pleasure by moving the wheel a nearer to or farther from the edge of the disc. Fig. 222 is another combination of discs suitable for couplings with only one bearing. The disc b is keyed on one shaft, and is recessed on the face, to receive the smaller disc, c ; this disc is sunk flush with the face of the other, and is screwed tightly Fig. 222. up to it by means of the ring a, which is bolted to the disc 6, and secures that marked c. Between the three plates, a, b, and c, annular pieces of leather are interposed, which bring them all to a proper bearing. This combination, termed a friction coupling, is useful for preventing breakage of the connectidns in case of a sudden stoppage or reversal of the motion. It is plain that the holding power of the coupling depends simply upon the lightness with 88 OX MACHIXERY OF TRANSMISSION. Avhich the discs are screwed together, and the consequent fric- tional force of the surfaces of leather and metal. Besides these more permanent forms of couplings, there are other contrivances adopted when the object to be attained is the engagement and disengagement of certain parts of the machinery or gearing during the course of operations. With the same view of admitting of this disengagement of the connection, in cases of sudden stoppage or reversal, the coupling, fig. 223, is sometimes employed. Fig. 223. In this instance, the shaft is supposed to be continuous, and the coupling may be termed a disengaging coupling, a and h are the two parts of the coupling, formed on the acting faces into alternate projections and recesses, such that they correspond with and exactly fit into each other when in gear. The part a is, in this example, cast on a spur or bevel wheel, from which the motion of the shaft is supposed to be taken off. Both of the parts a and 6 are, to a certain extent, loose on the shaft ; the former being capable of moving round on it, though deprived of longitudinal motion by washers and a collar, marked e, and •the latter being free to slide on the shaft, though prevented from turning on it by a sunk key, which slides in a slot inside the clutch or sliding piece h. The mechanism is put into gear by means of the lever d, which terminates in a fork with cylin- 0^ EXGAGING AND DISENGAGING GEAR. 89 drical extremities c ; and it is obvious that, by the contact of the flat faces of a and h, the latter will immediately carry Avith it the other part at the same speed as the shaft. Supposing, now, that the motion of the wheel a is suddenly accelerated, the oblique faces of the couplings immediately fall out of contact, and slide free of each other, leaving the couplings clear, and the shaft free to continue in motion. In the old form of this contrivance, known as the sliding bayonet clutch, the part b, instead of the toothlike projections on the face, had two or more prongs which laid hold of coiTe- sponding snugs cast on the face of the part a, which, moreover, was usually a broad belt pulley, introduced with a view to mo- dify the shock on the gearing on throwing tEe clutch into action. In an older form still, the pulley was made to slide end long- on the shaft. A form analogous to this was known as the " lock pulley," a few specimens of which still remain in the older factories. Instead of the end long motion common to the other modes, the parts were " locked" together by a bolt fixed upon the side of the pulley, and which, when shifted towards the axis, engaged with an arm of a cross, of which the part b, in the pre- ceding figure, is the modern representative. The bolt was wrought by means of a key and stop, the turning of the key throwing back the bolt, and thereby unlocking and disengaging the pulley. The form of coupling represented by fig. 223 is particularly applicable when the impelling power is derived from two sources — a circumstance which frequently occurs in localities affording water power to some extent, and yet not in sufficient abundance for the demands of the work. The defi- ciency is usually supplied by a steam-engine; and the two powers are concentrated in the main line of shafting by a coupling of the kind depicted. In cases of this kind, the speed of the shafting being fixed, and the supply of water inconstant, the power of the water-wheel ought to be thrown upon the wheel a «, and that of the engine upon the shaft at another point. By this arrangement, the speed of the line can be exactly regulated by working the engine to a greater or less power, according to the supply of water. The proper speed of the water-wheel will likewise be maintained, which is of importance in economising the water power. 90 ON MACHINERY OF TRANSMISSION. " The same form of coupling is also used occasionally for engaging and disengaging portions of the machinery. But for this purpose the object is to obtain a mode of connection by which the motion may be commenced without shock ; for, ia consequence of the inertia of all material things — that is, the tendency which every portion of matter has, when at rest, to remain at rest, and when in motion, to continue to move — the parts of the mechanism, when acted upon too suddenly by a moving power, are liable to fracture and disarrangement. It is a law in mechanics that when a body is struck by another in motion some time elapses before it is diffused from the point struck through the other parts; consequently, if the parts receiving the blow liave not sufficient elasticity and cohesive force to absorb the whole momentum of the striking body till the motion be transmitted to the centre of rotation, fracture of the body struck must necessarily ensue. Hence, in a system of mechanism, any parts intended to be acted upon suddenly by others in full motion ought not only to be strong, but they ought to be capable of yielding on the first impulse of the impelling force with as little resistance as possible, and gradually bring the whole weight into motion. The common mode of driving by belts and pulleys accomplishes this object very satis- factorily. In this the elasticity of the belt comes into action ; and being thrown upon the pulley by the strap guide or fork, it continues to slip, till, b}'- the friction between the sliding sur- faces, the belt gradually brings the cjuiescent pulley into full motion. This mode of connection is unexceptional when the power to be transferred is not great ; but its application to large machinery is attended with inconvenience." * In figs. 224, 225, two other forms of clutches are shown, as often used to connect the shafting of different parts of the same mill, where it is not necessary to throw into or out of gear when running at full speed. They consist of a fixed and sliding box, one on each shaft, with teeth or projections which fit in corresponding notches. The sliding box has a groove turned in it, in which a forked lever works, as at a (fig. 224) and at a (fig. 225), by which it is drawn backwards or forwards as the case may be. The peculiarity of the clutch (fig. 225) is that of * Extract from Engineer s and Machinist's Assistant, p. 144. ox ENGAGIXG .VXD DISENGAGIXG GEAR. 91 the driving shaft, which, reversed by any accident in its motion, as is not nnfrequently the case in starting and stopping the steam engine, the sliding clutch is forced Lack by the wedge-shaped faces of the projections, and the machinery thrown oiit of gear. Fie;. 224, rijr. 226. Fig. 226 shows one of these clutches on a small scale, fixed on a line of shafting beneath the floor of a mill. It is placed be- tween two standards eta, sup- porting the ends of the shaft, and the lever b working on a pivot at bottom, and having a pin work- ing in the groove of the sliding clutch box, serves for throwing the driven shaft into or out of gear whenever it may be necessary. Another ingenious contri- vance, I believe invented by Mr. Bodmer, is shown in figs. 227 and 228. It consists of a box a a running loosely on the driving shaft s s, but carrying the bevel wheel b b, which gears into another wheel on the driven shaft, not shown in the figures. Tightly keyed on the driving shaft s s is a boss c c, with two trunnions, on which slide two friction sectors k k ; the outer 92 OX MACIIINEEY OF TEANSMISSIOX, surface is coated Avith a copper plate, accurately fitting the interior surface of the running box a a. The boss c c carries Fig. 227. ON ENGAGING AND DISENGAGING GEAK. 93 also four projections eeee, which serve as guides for four screws, alternately left and right handed, and attached to the nuts // and levers gg; these screws act on the extremities of the friction slides k k, so that when the levers g g are drawn back they are both with equal pressure forced upon the inner surface of the box a a. As the pressure can be very regularly and gradually brought on this box through the levers and screws, the motion of the driving shaft s s is communicated with perfect regularity, and Avithout shock to the bevel wheel b b. In the above description I have given such examples of engaging and disengaging gear as are most commonly in use. Others of a more complicated character might be cited, but they are not to be recommended as applicable in general practice. The last form, figs. 227 and 228, is, however, specially noticed as suitable for gunpowder mills, where the greatest possible freedom from shocks is essentially necessary. Fig. 229. 9. Hangers, Plummer-blocks, d:c.,for carrying Shafting. Shafting is supported in three ways, viz. on foundation stones in the floor, beneath beams suspended from the ceiling, and to the walls of the mill. This necessitates as many different forms of framework, known as hangers, plummer-blocks, standards, &c. The simplest mode of support- ing a range of light shafting is from the floor, and apedestal suit- able for this purpose is shown in fig. 229. It consists of a cast iron base plate and column, with deep "wings a a cast on to strengthen it free from vibration. The upper portion is hollowed out to receive the lower brass step, and the cap carrying the upper step. When the entire pressure of the shafting is downwards the upper brass bush is omitted, and the cap is cast 94 ON MACHINEET OF TKAXSMISSIOX. hollow and kept full of grease, so as to secure the most perfect lubrication of the journal of the shaft. Fig. 230 shows a pedestal for bolting to a wall, the chief Fi". 230. difference being that the cap is now fixed on its inner side b}'' a wedge or cotter (c). In this figure a shell cap a is shown. If the pull is upwards, and two brasses be required, " lugs " have to be added to the extremity of the pedestal and cap for bolting the two together. There are various ways of suspending ranges of shafting from the ceiling, according to the means which exist for their attachment. If wooden beams, as s, are present, the hanger has a large plate {a), which bolts to the side of the beam, as shown in figs. 231, 232. The caps are fixed by a cotter, as in the previous case. Figs. 233, 234 show a front and side elevation of another form of hanger for attachment to wooden beams. In this case there is provision for a second line of shafting, at right angles to, and receiving motion from, the primary line. For this purpose a small plummer block is bolted on to a recess at the side of the hanger. The thrust, owing to the pair of bevel wheels ox SHAFT HAXGEKS AXD PLUMMER-BLOCKS. f'5 which would be placed near this hanger, is no longer simply ver- tical, and hence two brass steps are placed for the journal of the Fio;. 231. Fig. 232. principal shaft, with a bolt at d, fig. 233, in addition to the cotter, to keep the cap in its place. Fio-. 235 shows another form of light hanger sometimes era- ployed in weaving sheds, and also in use for supporting shafts 96 ON MACHINEKY OF TRANSMISSION^ in fire-proof mills, being bolted up to the under side of the cast- iron beams, as shown at fig. 237. Fig. 236. Fig. 235. ox SHAFT IIAXGEKS AND rLUMMER-BLOCKS. 07 Where greater strength and firmness are required, especially in long hangers in which there is considerable leverage, the arrangement shown in figs. 236, 237 is adopted ; the hanger in this case is bolted to a cast-iron beam, and by an extension of the flange plate to the brick arch, which springs from the beam t, it is firmly secured to both beam and floor. At e is a screw for tightening the upper brass step on the shaft. More complicated arrangements are sometimes necessary where two or three ranges of shafting have to be brought in connection with each other by means of bevil or mitre wheels. Fisfs. 238 and 239 show a front and side elevation of this Fig. 238. arrangement, which may serve as a type for others. The hanger is attached to a cast-iron beam A, by hooked bolts with nuts beneath the top plate, as shown at a «, care being taken in this attachment not to tveaken the flange of the iron beam by boring holes in it. Double brass steps are necessary in this case for the main line of shafting, and also for two smaller rauges at right angles to it, which revolve in opposite directions, as shown at fig. 239. VOL. II. H I 98 ON MACHINERY OF TEANSMISSIOX. Fig. 239, A very frequent case in practice is the connection of two ranges of shafting, at right angles to each other, at the corner of a room. This is effected by letting into the corner of the building a cast-iron frame, commonly known as a wall-box, which serves as a foundation for the plummer-blocks carrying the shafting. Such an arrangement is shown in fig. 240 in elevation, and in fig. 241 in plan. The box w, iv, iv, is built into the wall, and bolted both to it and to the cast-iron beam b. It carries two plummer-blocks on a plate firmly supported by brackets. The wall pieces in these two figures are similar, but with a slightly different arrangement of the plummer-blocks. Irrespective of the various forms of engaging and disengaging apparatus, it mil be necessary to consider the position, form, and proportions of the wheels and shafting required in mills where the power is divided and widely distributed. To show the enormous extent to which the concentration of machinery in one building has been carried, I may mention that in mills of my own construction there have been on the average not less ON SHAFT HANGERS AND PLUMMER-BLOCKS. 99 Fiji- 240. than 450 wheels and 7,000 feet of shafting in motion. In the large mills at Saltaire there are upwards of 600 wheels and 10,000 feet, or two miles, of shafting distributed over an area of Fig. 241. (Plan.) H 2 100 ON MACHINERY OF TRANSMISSION. flooring equivalent to 12 acres. In com mills and iron works, where the machinery is more closely connected with the prime mover, these considerations are of less importance; but in factories for the manufacture of textile fabrics the machinery covers a great extent of surface, and the greatest care is ne- cessary in giving due proportion to the transmissive machinery, in order to secure uniformity of motion at the remotest parts of the mill. In gearing a mill, the first consideration is the power of the engines, the position of the machinery to be driven, and the strength, diameter, &c., of the first-motion shaft, and other requisites for the transmission of motion in a well-geared mill. It is upwards of twenty years since the fly-wheel was converted into a first motion, and a new system of trans- mitting the power of the steam engines to the machinery of the mill introduced. Previous to that time it was effected by large spur-wheels inside the mill, now it is taken direct from the circumference of the fly-wheel.* The advantage of this system was the abolishing of the cumbrous first-motion gearing ; and the requisite velocity being already present in the fly-wheel, it was only necessary to cast it with teeth, and to take off the power by a suitable pinion at the level most convenient for the purposes of the mill. In another place I have given general rules for the pitch, breadth and strength of the teeth of wheels. The Table (p. 101), computed from examples which have occurred in my own practice, exhibits the best proportions of spur fly- wheels to secure durability of both wheel and pinion. It will be observed that the diameters of the fly-wheels are not always proportionate to the power of the engines, nor yet to their respective velocities. In practice, it is impossible to maintain imiforraity in this respect, as, in order to meet all the requirements of manufacture, it is necessary to deviate from fixed principles, and to approximate as near as circumstances will admit to the diameters, weights, and velocities of wheels, as may be found convenient to produce a maximum effect. Compare Part I.. Prime Movers, page 248. ON FLY WHEELS AND FIRST MOTIONS. 101 Table 9. — Dlimeters, Pitch, Velocity, &c., of Spur Fly-wheels of THE NEW Construction. Nominal Power of Diameter of Pitch Breadth of Cog in Inches. Velocity of Pitcli-line Steam Kngine, Horse-power. Fly-wheel. Feet. Inches. in Inches. per Minute in Feet. Two 150 = 300 30 U 4* 16 p Single = 50 13 3| H 12 Two 100 = 200 24 5 4 14 tM Two 80 = 160 23 4 4 14 Two 80 = 160 22 4 4 14 Single = 60 19 Oi 3f 3;- 12 Two 70 = 140 24 5" 12 2| Two 70 = 140 22 Si s? 14 f_^ Two 50 = 100 21 3t 12 Two 40= 80 21 3i: 10 3 ^ Two 45= 90 20 34 12 fc£-" Single = 50 18 2k 3? 12 Two 35= 70 16 0| 3? 10 0.? Single = 40 17 10 3 10 g5 Two 25= 50 13 10 3 10 Single = 25 8 lU 3 12 Two 20= 40 15 6" 2k 7 > Two 25= 50 15 4^ 2i 8 J^„ Single 25 15 4i 2k 7 '0 Two 18= 36 13 O" 2k 8 _o Single 15 10 ^ 7 k Single 18 17 11 2 6 j3 Single 12 10 2 5 H Of late years, the speed of the piston of factory steam engines has been accelerated from 240 to 300, and in some cases to 350 feet per minute. This united to the increased pressure of steam nearly doubles the power of the engines to what they were thirty years ago. The standard speed of a Bolton and Watt 7 feet stroke engine previous to that date, was seventeen and a half strokes per minute. In closing this section of practical construction, I may state that the couplings, engaging and disengaging gear, including the different forms of hangers, fixings, &c., are taken from my own designs, first introduced as a substitute for the cumbrous attachments that were in general use previous to the years 1820 and 1823. Having determined the diameter, speed and strength of the fly-wheel, the next consideration is the material, diameter, &c.. 102 ON MACHINERY OF TRANSMISSION. of the main shaft. These are usually of cast-iron, and their diameters depending on the power transmitted through them, and the velocity at which they revolve, will be found by the tables and formula already given. The distribution of the power is usually effected by a vertical shaft, extending from the bottom room, through the various floors of the mill, to the top story; the power being taken off at each stage by a pair of bevil wheels. This arrangement, as shown in fig. 242, repre- sents one engine-house with a section of part of one division of the mills at Saltaire ; and this may be considered as a type of other mills adapted for spinning and similar purposes. It will be observed that there are four divisions in the Saltaire mills — one for the preparatory process, one for the wool combing, another for the spinning, and a fourth for the weaving. All these are driven by four steam engines, each of 100 nominal horses power, but collectively distributing a force through these different departments of upwards of 1,250 horses. On referring to the drawings, figs. 242 and 243, which re- present a cross and longitudinal section of the mill, it will be seen that the vertical shaft A A, is driven direct from the fly- wheel by the horizontal shaft a, giving motion to the machinery in each room as it ascends. It is fixed on a solid pier of ashlar, as shown at fig. 244, page 106, and supported on strong cast-iron plates and bridgetrees, firmly secured by bolts to the foundations below. In each room it is securely fixed, by cast- iron frames and boxes, forming a recess for the bevil wheels, into the wall which divides the engine-house and the rooms above from the mill. This wall is generally made strong and thick, with sufficient weight to resist the action of the wheels prepared to drive the main lines of horizontal shafts with a speed and force equivalent to the work done in each room. In the case of the Saltaire mills this is considerable ; nearly 300 horses' power being distributed through the upright shaft alone, the remainder being carried off to the loom shed by a second wheel, working into the bevil wheel a, on the horizontal shaft b, but not shown in the drawing. It is important, in mills where powerful steam engines are employed, that the foundations and fixings to which the main shafts are attached are of the most ox VERTICAL SHAFTS. Fig. 242. 103 104 OX .ArACIIIXErtV OF TRAXSMISSIOX. Fig. 243. ■^^^^:& -i^t^^v-^^ -y^sj^^x ^>^^>^^^^g^'^^'^\^s^-\-»:y^l^^^'^^\^ ox VERTICAL SHAFTS. 105 substantial descriptiou, and the greatest precaution is necessary in order to secure them from vibration, and to render them perfectly rigid when the whole force of the engines is applied. In the Saltaire mills, as in many others for the manufacture of cotton, flax, and wool, the preparatory machinery, such as carding, combing, roving, &c., is generally driven by lines of horizontal shafts, or by a series of cross shafts, branching off at right angles from the main line extending down the centre of the room, as shown at c c in No. IT. room. Nos. III. and IV. rooms are driven by the longitudinal shaft in No. III. ; and Nos. V. and VI. by the shaft in No. V. room. On this plan it will be noticed that the spinning machinery is driven by iron pulleys from the horizontal shafts, at a velocity of nearly 200 revolutions per minute, and the straps or belts from those pulleys are directed by means of guide pulleys to the machinery in both rooms. For this purpose, iron boxes are inserted into the arches supporting the floors, for the ad- mission of the straps to the machinery in the upper floor. It will not be necessary to give the dimensions of the shafts in each room, as these details and calculations must be left to the judgement of the millwright, and the nature of the work they have to perform. Suffice it to observe, that the vertical shaft A is 10 inches diameter through the first two rooms, 8i inches through the third room, and 6^ inches to the top ; the velocity being 94 revolutions per minute. As respects the couplings for this shaft, we may refer the reader to the Table of Dimensions (page 109) made from couplings actually in use, and which have been found, by experiment, serviceable in every case where strength and durability are required. Grreat trouble is sometimes experienced with the foot of the vertical shaft, which, from its weight and the great pressure upon it, has a tendency to heat, unless sufficient bearing-area is allowed and the parts kept thoroughly lubricated. The general arrange- ments of the footsteps and gearing in large mills are shown in fig. 244 : s s is the first motion-shaft, and 1 1 the vertical shaft ; a a the bevil wheel on the former, and h b the bevil wheel on the lattir; c a plummer-block for the first motion- i06 OX MACHINERY OF TRANSMISSION. Fig. 244. ' ' '"'■ "-J i\ i ON VEKTICAL SHAFTS. 107 shaft, and dd the box coiitaiuiug the brass footstep for the vertical shaft: this box rests on a large base plate, bolted to the foundation stones and to the wall of the engine- house. In order to insure a constant supply of oil to the bearing, it is usual to cut away nearly the whole depth of the footstep, or that portion of the brass in the corner opposite to the thrust of the bevil wheels, as shown in the plan, fig. 24.4 ; this cavity is then kept full of oil, and lubricates the shaft throughout at every revolution.* Again, in cotton, woollen, and flax mills, when the first motion and vertical shafts have been duly proportioned to the work they have to perform, it becomes necessary to consider the diameter, speeds, &c., of the light shafting for driving the machinery in the different rooms. The formula given for strength, &c., in a former part of this work, will apply to this description of gearing and mill-work where the length does not exceed 120 feet. In long ranges of shafts, of from 150 to 200 feet in length, where the power applied to the machinery at the end of the room 'is considerable, it is essentially neces- sary to increase their strengths in order to prevent torsion or twist. This is a consideration of much importance, and requires careful attention, as long ranges of light shafts are very elastic — they, in some cases, effect nearly a complete revolution at the point of imparted motion before the extreme ends begin to move. The result of the power so irregularly transmitted by the spring of the shafts, resolves itself into a series of ac- celerated and retarded motions through the whole line of shafts, and imparts to the machinery in one-half of the room a very variable motion. Want of stiffness is a great evil in long lines of shafting, and, as we have already observed, instances are not wanting in which whole lines have been removed entirely from this cause. The transmission of power to machinery placed at different angles from the line of shafts, wliich is sometimes the case in old mills, has generally been effected by the universal joint A, * The reader may compare what is here said of footsteps with that in Part I. pp. 1G8, 172, on the steps for turbine shafts. 108 ON MACHINERY OF TRANSMISSION. fig. 245, which works moderately w^ell at an obtuse angle, but I have always found in my own practice that bevil wheels, as rig. 245. at B, fig. 246, are preferable and more satisfactory. They give much less trouble, and work with greater ease, than the uni- versal joint. Other examples might be given for the guidance of the practical millwright ; but, having to discuss these points Fig. 246. at greater length when w^e come to treat of the difiierent kinds of mills and different methods of gearing, w^e must direct the reader to those portions of the work w^hich concern his own immediate practice. The following Table exhibits the diameter of shafts, length of journals, diameter and proportions of couplings, &c., derived from actual practice, which may be useful to the less expe- rienced millwright and engineer: — ON THE TROPORTIONS OF SHAFTS. 109 Table K . — Length DlAMETEI) , &C., OF Couplings, Coupling -BOXES, &c. Diameter of Shaft. Length of Neck. Diameter of Coupling. Length of Lap. Length of Box. Diameter of Box, Thickness of Metal. Ijandlf 3 n 2 H H 1 8 If H 3 2| 5 5 1 2 4 H 2i 5* H H 2i 4i H H 6 6 H n 4 3 6^ 6| If 2J 5 H 3i 7 n u 3 5i 41 3i 7* 71 H H 6| 5 3| 8 H If H H 5i 3| 8i 8| i| 4 7 6 4 8i H If H 7i H 4^ 9 101 2 5 8 n 5 10 Hi 2 5^ 8i 8 5* 11 12i 2| 6 9 9 6 12 13^ 2i Gi H 9f 6^^ 13 14| 2i 7 m lOi 7 14 16 2| 7i Hi Hi 7i 15 17 2| 8 12 12 8 16^ 18 3 8A m 12i 8^ 17 19 3| 9 in 13 9 18 20 3| H 14 131 n 18 21 H 10 iH 14 10 m 22a H 11 15 16 11 20 24 4 12 IG 17^ 12 21 26 4| 13 17 18i 13 22 m 4i VOL. II. h7 110 SECTION V. ON MILL ARCHITECTURE. CHAPTER I. ANCIENT AND MODEKN MILLS. In the early stages of civilisation, when industrial progress was at a low ebb, and in those days when the whole population was trained to war, and a miserable -system of tillage existed, mills were little in demand, with the exception of corn and fulling mills ; the former to grind oats and barley, and the latt^er to mill a rough description of serge or blanket. At that period, mill architecture was out of the question, as the dwellings of the retainers, and those employed in the field or manufactory, were mere hovels, and the architecture of the country was confined to churches, public buildings, and the mansions of the barons or lords of the soil. In such a state of society mills were simply sheds, with water-wheels having straight floats, and a long conduit or spout to carry the force of the water descending from the higher fall against the float-boards below. In process of time, ..as the population increased in numbers and intelligejice, new demands for food and clothing were created, and a new description of mills was introduced to meet the requii-ements of a superior class to those under the feudal system, who were chiefly engaged in war and plunder. At this period mills were improved and enlarged, but there were no attempts at architec- ture ; and, what is still more surprising, the engineers and millwrights of those days appear to have had no idea of the advantages derivable from large water-wheels, but contented themselves with additional wheels to meet the demand of additional work. On these occasions every pair of millstones and every pair of fulling stocks had their separate water-wheels, and these were multiplied according to the demands or neces- sities of the trade. Fig. 247 represents a plan of the wheels. ox MILLS OF ANCIENT DATE. Ill and the way in which they were arranged, in order to give motion, as was then the fashion, to three pairs of millstoneSj with a di'essing machine and sieves, as the case might require. FiR. 217. .-V Most of the mills in this country and in other parts of Europe, were of this description up to the middle of the last century ; and it was during the days of Smeaton that mills began to assume a better system of classification, and that concentration of machinery and power, which ultimately led to the high state of perfection in which we now find them in this country. Immediately succeeding Smeaton came the late John Eennie, who built the Albion steam mills, and effected a new system of concentration, totally different to that in use, for corn mills driven by water. The steam engine was, therefore, the first innovator and improver of concentrated power ; and Mr. Eennie availed himself of its introduction to effect a new arrangement of the machinery in mills, tending to meet the requirements of a new power concentrated on one point, and diverging in 112 OX MILL ARCHITECTUEE. different directions to reach the various machines of the manufactory. This was an important step gained in the classi- fication of the machinery. It caused a change in the con- struction of water-wheels by increasing their diameter and width, and by making one wheel do the work of two or three on the old plan, the water-wheel being brought to bear upon the machinery in the mill, on the same principle as that of the steam engine. For many years the old plan still lingered in the minds of the millwrights of the last century, and it was not until the year 1824 that an improved system of applying water power to mills was effectively introduced. This was accomplished at the Catrine Cotton Works in Ayrshire, at the above date. From twenty to thirty years previous to that time these works were driven by four wheels at different parts of the building, with a divided fall of 48 feet, one half the fall being appropriated to one of the mills and the other to another upon the lower level. In the new wheels, a description of which is given at page 126, Vol. I., the two falls were united, and the whole power concentrated in a separate house, equidistant between the two mills, and a line of strong shafts projected at right angles from the wheels a,nd conveyed the power to the machinery in each. From this system of united force great advantages were derived, both in water and steam, which ultimately led to the arrange- ments now in use, of having both water-wheels and steam- engine erected separate from the mill, thus rendering the establishment free from damp and heat. Water-wheels are now upon a very different system than heretofore, and instead of being sunk in deep trenches in the very centre of the mill, obstructing the different processes of manufacture, and where it is next to impossible to get near them for repairs, they are now erected in a commodious house with broad platforms and galleries, six feet wide, and from which every part of the wheel can be reached. The concentration of motive power bearing direct from a single point upon mill machinery, led to the introduction of long lines of shafting to reach such machinery at the extreme end of the different flats of the mill, and these, again, as al- ready explained, suggested other improvements in the buildings. ON EARLY COTTON MILLS. 113 particularly in cotton mills, where they are not unfrequently extended to a length of 300 to 350 feet. It is in the recollection of persons still living, when the operations of carding, spinning, and weaving of cotton, flax, and wool, were chiefly carried on in the farm-house and the cottages of the labouring poor, and it is not more than fifty years since the power-loom was introduced, and became the pre- cursor of future changes which ultimately destroyed almost every vestige of our domestic manufacture. It is not for me to offer an opinion on the effects of these changes on the whole of our industrial population; suffice it to observe, that it has altered the domestic habits of the people, and concentrated within large and substantial buildings great numbers of people employed in the different processes of manufacture, which, formerly distributed over a large surface of country, are now concentrated under one roof. As late as 1784, there were no factories, properly so to speak, but the improvements in cotton machinery introduced by Arkwright and Crompton, suggested enlarged space in the shape of separate buildings ; and the large profits arising from the cotton manufacture at that time, enabled the proprietors to build mills, some of them considered of colossal dimensions. At first, these mills were square brick-buildings, without any pretensions to architectural form, as shown at Fig. 248. This Fig. 248. Siiiirii !*!■!■ I lilt description of building with bare walls was for many years the distinguishing features of a cotton mill, and for many years they continued to be of the same form and character throughout all VOL. II. 114 OX MILL ARCHITECTURE. parts of the country. About the year 1827, I gave designs for a new mill of a different class, and persuaded the proprietor to allow some deviation from the monotonous forms then in general use. This alteration had no pretension to architectural desio-n; it consisted chiefly in forming the corners of the building into pilasters, and a slight cornice round the building, as shown in Fig. 249. This simple change of form gave a new Fig. 249. ^^'s [liriBia.BiiiiiB ipiii§iiiii.a|ji *eif isiiiilllil i§ii!,iii@i;iii ^fc impetus to the building of factories. It was speedil}^ copied in all directions with exceedingly slight modifications, but always with effect, as it generally improved the appearance of the buildings, and produced in the minds of the millowners and the public a higher standard of taste. These attempts at improvement led to the employment of architects, and we have now, as may be seen from the annexed view of the fapade of Saltaire, the factory buildings in this country vieing with our institutions and public buildings as works of art, both in the power and harmony of their parts and the tout ensemble of their appearance. The above style of architecture is not confined to mills of such large dimensions as those of Saltaire, but other forms, according to the taste of the builder, are generally adopted in most mills, greatly to the benefit of the o^^^ler, and advanta- geous in other respects as regards ajipea-rance and progressive improvement in the useful arts. ox IMPROVED MILLS. \\5 Fig. 250. Irrespective of the external appearance, the results of improvements in mill architecture, were manifest in the desire which they induced to elaborate with greater certainty and effect the art of design ; to accustom the mind to objects of interest which embodied lines of harmonious proportion, and united in these constructions the taste of the architect and the stability of the engineer. To these may be added the improvements that were introduced in the general ar- rangements of the buildings, their adaptation for the recep- tion of the different kinds of machinery ; security from fire and other requisites for carrying on a large and successful process of manufacture. Contemporaneous "svith the architectm'al improve- ments in mills, the shed principle lighted from the roof, or the " saw-tooth " system, came into operation. It was chiefly adapted for power-weaving, and contained many advantages in having the machines on the ground floor, accompanied with a slight degree of moisture, which was considered beneficial to the processes carried on. Since the introduction of the shed principle as a convenient building for the reception of cotton machinery, it has been generally adopted for workshops, and various other descriptions Fig. 251. 116 ON MILL AECHITECTUEE. of manufactures. The workshops at Woolwich and the Enfield Lock Eifle Factory are upon this principle, which have great advantages where the different processes of manufacture are continuous from one department to another, and where the whole can be carried on by rail or tramway, on the ground floor. It is difficult to estimate the advantages of this descrip- tion of building for manufacturing purposes ; they are, however, considerable, and, where land can be had moderately cheap, it is found superior in many respects, particularly as regards light, to buildings composed of three, four, or more stories. Another description of building, composed entirely of iron, has been introduced for mill purposes, namely, a combination of cast and wrought iron, as exhibited in a small corn mill, constructed by Messrs. W. Fairbairn, Sons, & Co., Millwall, London, from my own designs in the year 184L This build- ing was, to the best of my belief, the first iron house con- structed in this country, and was from its unique character one of the most successful constructions of its kind. It was formed of hollow cast-iron pilasters composing the standards and framework of the building, which gave it an architectural appearance, and added considerably to its durability and strength. The spaces between the pilasters were filled up with cast-iron plates to the height of the first floor, and the two remaining stories were formed of wrought-iron plates, riveted to the flanges of the pilasters as shown in Figs. 252, 253, 254, and 255, pages 119, 120, 121, and 122. The whole of the vertical sides and ends were covered with a corrugated iron roof, and the floors were supported by iron beams and columns in the usual manner. This building when completed was exhibited at the works, Millwall, and from that time to the present, a large trade in the construction of iron houses, churches, """^^arehouses, &c., has been carried on between this country and tlte Colonies, India, and America. 117 CHAPTER IL ON CORN MILLS. In the first part of this work was sketched a very brief notice of the antiquity of corn mills, and the state in which grinding went on from generation to generation, until it came down with comparatively little improvement to the present time. During the Jewish period, Moses speaks of the nether and upper mill- stones, and for a succession of ages in Egypt, Greece, and Rome, the quern and some other description of mills, driven by horses or by bullocks, appear to have been in use without change or improvement of any kind. The same may be said of the Middle Ages, which were an}i:hing but fruitful of im- provement or mechanical invention ; and, until the close of the last century, little or no progress was made in the process of grinding, or the development of those principles by which the whole operation is reduced to a system. Corn mills, like every other description of milling, have of late years undergone great changes, and the introduction of steam has given certainty and effect to the mill operations of every description of manu- facture, that was inconceivable at a previous epoch. The fact of having motive power at command in every district of the country, mills being no longer dependent upon the state of the wind or the supply of water, has now as nearly as- possible supplanted the old wind and water contrivances,' and transferred the operation of grinding, with .a^i^its necessary improvements, into the very heart of towns. From this cer- tainty of action we derive most of the changes and improve- ments that are now visible in corn mills, and in every other description of manufacture throughout the country ; we have therefore now to show in what these improvements consist, and VOL. II. *i3 118 ON CORN MILLS. how they may be maintaiued upon sounder principles than those known to our forefathers. The corn mills chosen for illustration are, one of three pairs of stones erected at Constantinople for the Seraskier Halel Pasha in 1842, and the other of thirty pairs of stones for a Eussian company at Taganrog, on the borders of the Black Sea. The first was built under conditions that the building should be entirely of iron, that it might not be burnt to the ground by the fires which so frequently occur in the Turkish capital. The other was intended for the purpose of grinding the large supplies of wheat which are grown on the steppes of Southern Eussia for the European markets, and also for the supply of bread and biscuits for the Eussian navy. It is now upwards of forty years since the new system of corn mills, having the millstones in a continuous line, was first adopted. For many years it was called in question, and it met with a determined opposition from the old millers and mill- wrights, who stoutly maintained that the bevil-wheel principle was decidedly inferior to the old plan of stones ranged round a large spur-wheel. Time, however, showed the advantages of the new plan, as it not only proved that the bevil wheels worked as well as the spur, but it gave greatly increased faci- lities for the operations of the mill in the different processes of cleansing, grinding, dressing, sacking, &c., of the flour, as it came from the machine ready for the baker. A description of this mill, and of the Old Union Mills, Bir- mingham, was published some years since by Messrs. Blackie and Son, in their work, entitled ' The Engineers' and Mechanics' Assistant,' and, as that work contains an accurate description of this system of mills, I have extracted from it large quotations, accompanied with improvements, which have been since intro- duced. Fig. 252 is a sectional elevation of the mill, the line of section being taken in a longitudinal direction, and exhibiting the position of the stones, the engine, and driving gearing, and of such i^ortions of the subordinate apjiaratus as are visible on the side of tlie mill which is exposed to view. ON IRON BUILDINGS FOR CORN MILLS. 119 It also exhibits the millstones p p p, sections of the elevators, screw creepers, and the wheat bins or hoppers, zzz. Fig. 252. In these will be seen the driving gear, first motion wheels, and vertical shaft, by which motion is transmitted to the ma- chinery in the floors above. ]20 ON CORN MILLS. Fig. 253 is a plan of the bottom floor, showing engine and boilers, corresponding to the above, and taken on a horizontal line passing through the lower story of the mill. Fig. 253. Fig. 254 is a transverse section of the entire mill, in which are shown the garners for undressed and dressed wheat, the mechanism by which it is cleaned and conveyed from the former into the latter, the sack teagle, &c. ON IRON BUILDINGS FOR CORN MILLS. 121 Fig. 254. Fig. 255 is a plan of the first floor, corresponding* with the plan, fig. 253, the line of section being taken through the first story of the mill. The house in which this mill is contained consists of an assem- blage of plates of sheet iron, A, A, A, of a suitable thickness, conso- lidated and bound together by the square cast-iron columns, or pilasters, b,b,b, and by the strong cast-iron girders, c,c,c, situated at such a height as to oppose and neutralise the strain of the prin- cipal working parts. It is surmounted by an arched roof, d,d, formed of plates of corrugated sheet-iron. A wall of masonry, e, e, is erected in the interior, for the purpose of affording a foundation for the bearings of the heavier gearing of the mill. The motive power is supplied by a high pressure steam-engine, f, of 12-horse 122 OX CORN MILLS. Fig. 2c ^S_< power, the distinguishing feature of which consists in its prin- cipal working parts being wholly enclosed within a large cast- iron column. By this arrangement gretft firmness and stability are imparted to the engine, while the space which it occupies is reduced to the smallest possible dimensions. The boilers, G,G, are situated in an adjoining part of the house, and their flues, n,H, are formed, in the usual manner, of brickwork, abutting ON BEVIL AND SPUR GEAR FOR CORN MILLS. 123 on the one hand against the wall e, and on the other against the side of the house itself. Thus the engine and boilers occupy nearly the entire half of the lower story of the mill. The whole erection is strengthened and bound together by the cast- iron beams i,i,i, which pass transversely through the interior of the house, and are supported in the middle of their length by the columns, J, J. On these beams, also, the flooring of the upper and lower flat is disposed. The fly-wheel k, k, of the steam engine is of that kind deno- minated spur fly-wheels, from the circumstance of their being formed with teeth, on the exterior of the rim, and thus serving at once to regulate the velocity, and to transmit the power of the steam-engine to which they are attached. The spur fly- wheel, K,K, the diameter of which is 9 feet 3| inches, gears with the pinion 'l, of 4 feet 1 Of inches diameter ; consequently, the velocity of the crank shaft is nearly doubled upon the horizontal shaft M,M, to which the latter is fixed, and which by means of the bevil wheels and pinions n,n,n, gives motion to the stones contained within the mill-stone cases, p,p,p. The shaft m,m, has a bearing upon the wall e, close to the back of the pinion l, and one in each of the standards o, o,o, to which the mechanism necessary for impelling and regulating the action of the stones is attached. Considerable difference of opinion exists amongst the mill- wrights of the present day regarding the comparative advan- tages of spur and bevil gearing as employed for driving grinding machinery. Into this question our limits do not admit of our entering ; in our examples we have chosen the latter method, as being that most generally practised. We may, however, be permitted to enumerate a few of the more obvious advantages attending the present system. 1st. It admits of the stones, whatever may be the number employed, being ranged in a straight line instead of in a circle, thereby economising space, and tending to a more convenient and economical disposition of the garners and apparatus by which they are fed. 2nd. It dispenses with the cumbrous and expensive frame- Avork necessary for binding together the parts of the system of spur gearing. 124 ON COKN MILLS. 3rd. It admits of the employment of wheel-work of a finer pitch, and consequently of a more smooth and equable action, than could be used in the other case. And, 4th. The use of the bevil gearing increases the facility of dis- engaging at pleasure any pair of stones which may require examinatiorr or repair. We shall now proceed to describe the mechanism of the various processes by which the grain is treated, both previously and subsequently to the process of grinding ; and, to avoid repe- titions, we shall notice these processes in the order in which they occur. The corn to be ground is deposited in the upper floor of the mill in the large garner, q,q, fig. 254, from which it is con- ducted through the spout, E, into the screening machine s,s, where it is cleansed of the dust and other extraneous matter which is found more or less combined with it. The corn enters at its upper extremity, and having been thoroughly agitated in its passage through the interior of the machine, and thereby divested of the greater portion of the refuse with which it was mixed, falls into a spout u, at its lower end, which conducts it to the elevator v ; being subjected in its passage through this spout to the action of a blast from the fan t, by which the remaining portion of the sand and dust that escapes with the grain, is carried off by a passage leading to the exterior of the house. The grain, after being thus cleansed, is caught by the elevator v, and raised nearly to the summit of the mill, where it is delivered, through an inclined spout x, into the creeper- box T,T, by which it is distributed into the feeding garners z,z,z. The corn which is supplied to the garners z,z,z, falls through the feeding pipes or spouts a', a', a', into the hoppers, by which the grinding apparatus is surmounted. After being reduced into flour, it falls through the pipes b', b', b', into the creeper-box y',y', by which it is transferred to the elevator v. By this elevator it is again raised to the summit of the house, and carried by means of the creeper y' to the dressing machine s', after passing which the different products are stored up in sacks, or otherwise disposed of, as may be most convenient. The machines and mechanism connected therewith will subse- quently be very fully described, and need not here be further alluded to. ON THE DIFFERENT PROCESSES OF GRINDING, ETC. 125 The gearing Ly which the subordinate machinery of the mill is driven, consists, first, of an upright shaft c', c' , set in motion by a pair of bevil wheels a, from the main horizontal shaft m,m. This shaft has its lower bearing in an arched standard embracing the shaft m, and at its upper extremity it is supported by a plummer-block bolted to a double bracket d', embedded in the wall E. Its motion is here transferred by means of another pair of bevil wheels h, to the horizontal shaft e',e', passing transversely across the mill. On this shaft are fixed the pulleys d and e, which drive the screening and dressing machines respectively, and a set of small bevil wheels c,c, serve to trans- mit the motion to the longitudinal shafts f',f', by which the elevators, creepers, &c., are propelled ; as also the short shaft g', by which the sack teagle is driven. We subjoin a list of the various wheels, pinions, and pulleys employed in this mill, and the velocities imparted by them to the machines driven by them respectively. Steam Engine F, 12-horse Po-v\T3e, makes Forty Revolutions of Crank-shaft PER Minute. j Driver. Driven. Description of Gearing. 1 Result. Revolutions per Minute. Diameter, Revolu- tions. Diameter. ft. in. ft. in. Spur pair k, l, . . 9 H 40 4 10^ 76 on horizontal shaft m. Bevil pairs n, n, n, 3 6 76 1 10 140 on the stones. Bevil pair «... 3 6 76 1 10 140 on upright shaft c'. Bevil pair h . . . 3 140 1 9 242 on transverse shaft e'. Bevil pair c,c . . 1 u 242 1 lU 140 on longitudinal shafts f'f'. Pulley d . . . . 1 6 242 1 363 on screening machines. Pulley e . . . . 1 6 242 1 363 on dressing machine s'. Pulley /■.... 2 140 6 560 on fan t. Pulley 9 . . . . 8 140 2 46-6 on elevators & creepers. Pulley "A . . . , 1 140 2 70 on intermediate shaft g'. Pulley i . . . . 1 6 70 2 47 on sack teagle h'. REFERENCES. A, A, A, the sheet-iron sides of the hou.'^e in which the mill is erected. B, B, B, columns for supporting and strengthening the structm-e. c, c, horizontal beams at the level of the first floor. D, D, the roof formed of corrugated iron. 126 ON CORN MILLS. E, E, a wall of masoniy, affording a foundation for the bearings of the driving gearing, &c. F, the steam engine by Avhich the mill is driven. G, G, the boilers. H, H, the flues and seat of the boilers. I, I, I, transverse cast-rron beams for supporting the floors, &c. J, J, columns for supporting these beams. K, K, the spur fly-wheel of the engine. L, pinion working into the above. M, M, the main horizontal shaft;. N, N, N, level mortice-wheels and pinions by which the millstone spindles are dri^-en. 0, 0, 0, the standards of the grinding machinery. p, p, p, the millstone cases. Q, Q, the large garner for uncleaned wheat. R, spout leading from the garner, Q, to s, the screening machine. s', the dressing machine. T, a fan attached to the wheat screen. u, spout leading from the Avheat screen to V, w, the first elevator. X, passage conducting the grain fi-om the first elevator to T, Y, Y, the creeper, by which it is distributed into z, z, z, the garners for feeding the stones. a', a', a', the feeding pipes. b', b', b', pipes by which the flour is delivered into y', y', the second creeper- box, conducting it to v', w, the second elevator. a, bevil wheel and pinion giving motion to c', c', the vertical shafts of the mill. d', a cast-iron support for the bearings of the vertical and transverse horizontal shafts. b, bevil wheel and pinion giving motion to e', e', the transverse horizontal shaft. c, c, a set of small bevil gearing, giving motion to f', f', the longitudinal horizontal shaft. d, e,f, g, h, i, pulleys for giving motion to the various subordinate machinery of the mill. g', intermediate shaft, conveying motion to h', h', the sack teagle. i', a lever for stopping and starting the sack teagle. k', k', hatchAvays by which the sacks are admitted or withdi'awn. \i■^ t^i ^M 9\ t t P.t lit ■_ll B_H JB W P if H B P jA -^ in dH -^ '-^ ^^ ^ M f^ |Pt W p w p R M_JL ft_ IL #' # # fl Ha M^ fl| Hi ^b Ml- Hi JK Hr ■- JB Ki _ Bii JB_- JH P -P _B!L Hi i 1 1 ■ t a 1 fl s-^i — m — a — a^^ ^1 u; V-j Ch - — - -TV^T / Lz:^ ox THE TAGANROG MILLS. I07 The next example of a corn-mill on a large scale is the recently-constructed mills of Taganrog, on the north shore of the Black Sea. It consists of 36 pair of stones and all the machinery requisite for grinding 180 to 200 bushels of clean dry wheat per hour. It was built for the purpose of a general trade, and a bakery for bread and biscuit for the Eussian navy, but the machinery for this latter department has not been erected, and the operations have hitherto been confined to grindino; alone. Plate I. is a front elevation of the mill, and Plate II. a plan showing the position of the engines. The engines work in con- cert with the cranks at right angles, and the boilers, which are sunk under the surface of the ground, immediately adjoining the engine-house, are fired from the space /. The chimney w' is placed in a line with the centre of the engine house and the mill. Plate III. is a longitudinal section which exhibits the position of the machinery, millwork, millstones, ttc. ; and Plate IV. exhibits a transverse section, taken from a line drawn through the centre of the engine house and the flywheel. The motive power is supplied by two 100 horses power engines united in the flywheel I, 24 feet 5 inches diameter. It is on the new principle of a first motion, with 230 teeth 4 inches pitch, and 14 inches broad on the tooth, and makes 24-7 revolutions per minute. The engines have a stroke of 7 feet, and the steam is supplied b}^ six boilers, each 30 feet 6 inches long and 7 feet diameter. The chimney is octagonal, and placed 40 feet from the engine house, with underground flues and an outlet of 5 feet wide at the top. The walls are 3 feet 6 inches thick at the bottom, and taper to 1 foot 3 inches at a height of 140 feet. The engines are situated behind in the centre of the mill, and the power is given off at both sides of the pinion, which gears into the flywheel at a velocity of 87*7 revolutions per minute. For a distance of 14 feet on each side the main shafts are 8^ inches diameter, for a farther distance they are 7^ inches diameter, and from this point they taper respectively to 6^- and 6 inches diameter on both sides. The distance between the centres of each pair of stones is 5 feet 6 inches, and they are arranged in a straight line running- parallel to the walls through the entire length of the buildintJ-. 128 ON COEN MILLS. The bevil mortice wheels on the main horizontal shaft are 3 feet 4f inches diameter, and the bevil wheels n n N on the millstone- spindles are 2 feet 1^ inches, and make 140 revolutions per minute. The elevators for meal dd rise perpendicularly at either end of the building to the attic story, and the shafts l l, for driving the subordinate machinery in the different flats, rises to the fifth story, giving off its power to the different machines on its course by bevil wheels. The third story of the mill contains the dressing and bolting machines F F and K K, also the wheat bins v v v for the supply of the corn to the mill- stones. These wheat-bins are about 11 feet square and 12 feet high, and are supplied by the elevator and creeper q and u, so that manual labour is entirely dispensed with. The fourth story contains the screening machines T t T, and the garners for the bolting machines h h, these being also supplied by creepers and elevators. The attic story contains the separators s s and the hoists e'e', &c., &c. The wheat enters the mill from the granary at n\ and by the elevator q is carried to the creeper e, by which it is conducted to the separators s s. Having passed through the separators, and the earthy particles, dust and small grain, having been abstracted, it enters the wheat screens T t ; here it is subjected to a thorough brushing, and the dust falls through the wire gauze of which the screen is composed. On its way to the creeper tj it is subjected to the action of fans J jj, which blow out any remaining dust ; it is then conveyed by the creepers to the wheat bins v v v, where it is stored, and supplies itself in sufficient quantity through the feed pipes www into the hoppers AAA, and from thence descends to the millstones ebb. After having been ground, it falls through to the meal creepers, by which it is conveyed to the elevators d d, and from thence, by another creeper, to the dressing machines and the garners for the bolting machines H n H. There the meal undergoes the last process, where the flour is separated from the bran and is ready to be stored in sacks for the market. * * Some few years ago two conical mills were introdiiced: the one by Mr. Schiele of Oldham, which consisted of a conoid of stone of peculiar form, placed with the base upwards, which merely fitted into a block of stone hoUowed out to receive it. B iLAdlard sc JBssaw wzar •^:b wtmp l-H-t-liH-H+i WHl-rf H EjidlcLTdsc ERECTED AT TACANROC. RUSSIA. IN I860 ^ WiUiajn. Fa-vrbcurn, & Sons. Miuwhtster TRAHSVURSI eECTIOK TlffiOTreH EMOrUE HOUSE -•.k P P W- '/ ■ CHANGES CAUSED IN THE TAGANEOG MILLS. 129 This large establishment was originally intended not only for the supply of biscuit for the Eussian Navy, but for export in the shape of flour in place of wheat. The Crimean war, the de- struction of Sebastopol, and the subsequent treaty of peace, whereby it was agreed that no vessels of war should be re- tained on the Black Sea excepting those for the protection of commerce, have changed the objects originally contemplated by the erection of these mills, and have caused the company to abandon the Baking department, and confine their operations to the simple process of grinding, dressing, &c. It is for these reasons that we are necessitated to confine our description to the various processes through which the corn passes ; and the construction of the various machines and the mechanical appliances for the saving of manual labour, are described in detail at the end of this section, so that further reference to them here is rendered unnecessary. In order to make the description as complete as possible, we append a list of wheels and speeds, including the table of references, which will be found serviceable. and in which it revolved. The form given to these stones was a curve, termed the equitangential tractory, which by revolving on its axis generates the conoid. The other conical flour mill was the invention of Mr. Westrup. The points of peculiarity in this mill were, that there were two pairs of stones to each mill. Between the two pairs of stones a cylindrical screen of about 2 feet 6 inches high was fixed. The lower instead of the upper stones revolved, and brushes were attached to the spindle, in the space between the two sets of stones, by which the finest flour is brushed through the vertical cylinder. The bottom stones are convex, and make about 250 revolutions per minute; the upper ones are concave, and about 2 feet 6 inches diameter. When the eye-hole is cut out, it leaves some 9 inches of grinding surface, and in that ^ddth the bevil of the cone is 4 inches. Cold air is introduced between the stones by means of a fun, which blows out the meal from between them. The stones are fed by means of a hopper placed on one side, with a feed pipe in the top of it, and an upright spindle carrying a dish, which, re- volving quickly, evenly distributes the corn. VOL. II. 130 ON CORN MILLS. o o o t-l bO _fl "3 cj ^ ts 50 g 0; cd sa ^ S o5 •HO) J "3 Cm M n .2 ^ .^.^„.,.^««.,»^-^^rvr..x.%«»,^-^«„.^«^ l> a> u t;~ CO ^~oc<^-*c<^oooookOO'^^T(^^^^o>Ol^■^l0^co«3e<^c<^(^^ oO'^t^M^oo-t aj 0^ So ^a ^ J S- -^ - •—1 ^ 3 £j s 0) s f^M Ph ol'PM pqpL4 MACHINEllY OF THE TAGANEOG MILLS. 131 REFERENCES. X X, the walls of the miU. YYY, columns for strengthening the building and supporting the floors. a a a, the roof of the building. f, the steam engine by which the mill is driven. J, the cylinder. c, the condenser. d f/, the feed pipes. c, the governors. g^ the main beam. h hj the foundations. Z, the spur fly wheel of the engine. m, the pinion gearing into the above. M M, the main horizontal shafl;. N N, bevil mortice wheels and pinions by which the millstone spmdles are driven. o 0, the standard frame and inverted cone supporting the millstones. P p, the millstone cases. Q, the elevator for Ufting the wheat from the garners to the separator. E, the creeper to supply the separators. s s s, the separators. TT, the wheat screens. J J, the fan attached to the Avheat screens. u u u, the creeper conveying the grain to V V V, the wheat bins, and through www, the feed pipes, to AAA, the hoppers, and to B B B, the millstones. CCC, the creeper for conveying the groimd corn to D, the meal elevator. E E, the creeper for conveying the ground corn to the cooling rooms ready to be supplied as required to F F, the dressing machines. G G, the creeper for conveying the groimd corn to H H, the garners of the bolting machines. K K, the bolting machines. L L, the shafts for driving the subordinate machinery. b', the bevil Avheels giving motion to the cross shaft of the dressing macliines. K 2 132 ON CORN MILLS. c', bevil wheels giving motion to d', the cross shaft for screening machines. A 'a', bevil wheels on upright shaft. I, the dust chamber for the wheat screens. V, the chimney. 0, the reservoir for supplying the boilers of the engine. z, the store room for flour. z', the space from which the boilers are fired. e', cross shaft for driving fans and creepers. f' f', pulleys for driving dressing machines. g' g' g', pulleys for driving dressing machines. ii' h' h', pulleys for driving fans for screens. i', pulley for creeper under wheat screen. j', counter shaft under separator. k' k' k', pulleys for separators. l', pulley for creeper over wheat screen. Ji', cross shaft for creeper over wheat garners. n', spur wheel for large creeper over Avheat garners. o', pulley for small creeper over wheat garners. p' p', pulleys for meal creeper on ground floor. q' q', pulleys for meal elevators. r' r', the chain barrels of the hoists. s' s', cross shafts for bolting machines. t' t', second cross shaft for bolting machines. During the siege of Sebastopol it was determined, on the urgent recommendation of Assistant-Commissary General Julyan, to effect an arrangement for supplying the troops daily with new bread and fresh flour from the grain of the surrounding country, by providing the means of converting the wheat into flour and baking it upon the spot by a floating mill and bakery- Having been consulted as to the best means of carrying out this proposal, drawings and plans were prepared for the mills and ovens, and two iron screw steamers, subsequently named the Bruiser and the Abundance, were purchased by the Grovern- ment for adaptation to this purpose, and were fitted with machinery by Messrs. William Fairbairn & Sons, the whole being completed in less than three months. It is curious to trace the history of the means by which large bodies of men have been supplied with food, and the obligations MACHINERY OF THE FLOATING MILL. 133 assumed by states for provisioning armies in times of war. We learn that, in the early period of Eoman history, grain was the only article of food issued to the soldiers, and was ground by means of a hand mill, which formed a part of every man's equipment; the flour was simply worked into a paste called puis, which constituted the principal food. The constitution of modern armies and the peculiar character of modern warfare render the soldier, however, more dependent upon the cares of the administration than was the case with the ancients ; and we have seen how prostrate and helpless they are, when deprived of the resources of a well-conducted and far-seeing commis- sariat. The French, Spanish, and other continental troops can live upon a moderate allowance of vegetable and farinaceous food, and a lump of oil cake will maintain a Russian for a week ; but it is widely different with the English, who become dis- organised when their rations fail. Under these circumstances it is a matter of essential importance to maintain a system of daily supply ; and hence followed the introduction of the floating mill and bakery. The arrangement of the floating mill is shown in figs. 256, 257, 258, and 259. Fig. 256 is a longitudinal section of the vessel; fig. 257 is a plan of the machinery, with the decks removed and partly in section; and figs. 258 and 259 are transverse sections of the vessel. The mill machinery is all driven from the propeller shaft A, fig. 257, which is driven by the engines b ; and the whole of the processes are performed without the aid of manual labour. The wheat is stored in the forehold of the vessel, and is raised by an elevator into the screw-creeper c, which conveys it into the corn-dressing machine d, where it is cleaned and winnowed. Thence it is again conveyed by the elevator e and the screw- creeper F into the hoppers G G for feeding the mill-stones ii h, by which it is ground. The grain is fed to the stones by the silent feeders i, now in general use in this and foreign countries. After being ground by the mill-stones ir, the flour or meal is delivered into the screw-creeper k, which conve3^s it to the elevator l, by which it is delivered into the flour-dressing machine M ; it is here freed from the bran and filled into sacks, having been separated into a fine and coarse quality. This 134 ON CORN MILLS. THE FLOATING MILL. 135 t!; 5 136 OX CORN ]\IILLS. Fig. 258. J80 i23*587S9 10 ii;;. 259. PERFORMANCE OF THE FLOATING MILL. 137 completes the whole process. The propeller shaft A is exposed under the mill-stones, but covered by an iron trough n in the other parts of the vessel. During the time the vessel was in harbour at Balaklava, the daily produce of flour from this mill was about 24,000 lbs., and that from very hard wheat, full of small gravel, and consequently the more difficult to grind. It was originally intended that the mill should be capable of producing 20,000 lbs. of bread per day, but it proved equal to a considerably larger production ; and not the least important of its good qualities was that it never got out of order during the whole period of service in the Black Sea. From the reports made to the Grovernment at home respecting its working, it appears that important advan- tages were gained by the introduction of this machinery for the use of the troops. There is probably no description of food so essential to the maintenance of health and the recovery of the sick as fresh flour and fresh bread ; and the salutary effects produced upon the health of the troops and the number of lives saved in the late war, by the abundant supply of wholesome bread and flour that was poured into the camp during the latter part of the siege, forcibly suggest the necessity of a light portable steam-engine and mill for grinding being constantly attached to the camp, whenever or wherever an army takes the field. This can be done at a very moderate cost, and, in my opinion, no army should attempt to take the field without it. The whole affair would not exceed the weight of a heavy siege gun, such as now accompanies our armies ; and there appears no practical difficulty in the way of introducing an engine capable of supplying newly-baked bread, from an oven con- structed in the smoke-box of a portable locomotive engine mounted on wheels and prepared to grind at the same time. The results of the working of the floating corn mill are given in the official reports at 20 tons of flour ground per day of 24 hours when constantly in full work ; and 1 8,000 lbs. of bread in 3 lb. loaves produced daily from the bakery. This rate of work was continued uninterruptedly for many months, and the machinery answered completely the object intended. The total quantity of bread produced in three months from 1st January to 31st March, 1856, was 1,284,747 lbs. : and the 138 OX CORN MILLS. expenses of working were 2,01 7L, or 3s. 2d. per 100 lbs. of bread made, including the expense of a sea establishment for the vessel, which would not be required where the vessel was stationary. The quantity of flour gTound in the same period was 1,331,792 lbs. with 358,172 lbs. of bran, the wheat supplied being 1,776,780 lbs. ; the expenses of working were 2050^., or 2s. 4c?. per 100 lbs. of wheat ground, or 3s. Id. per 100 lbs. of flour produced. The total cost of the flour produced was therefore about 25s. 3cZ. per 100 lbs., the wheat costing about IBs. per 100 lbs., and the value of the bran being deducted at 7s. per 100 lbs. or less than \d. per lb. The grinding of wheat was found to be performed quite satisfactorily whilst the vessel was at sea, even in a heavy swell causing an excessive motion, which tried the fitness of the machinery for the work to an unusual degree ; the grinding whilst the vessel is performing her voyage being obtained from the same power that propels her. On one occasion, when the vessel was steaming 6^ knots or 7^ miles per hour, 10 sacks of 168 lbs. each or 1680 lbs. of wheat were ground per hour, and the mill was kept in constant work for 35 hours, the men being divided into watches of four hours each; the mill con- tinued working well throughout, and was found to run more regularly than when the screw was disconnected. The mill machinery of the Bruiser is similar to that ordinarily employed on shore in this country, with such modifications only as were necessary to adapt it to its novel position, and fit it to sustain the constant and varying motion of the vessel at sea. These difficulties were overcome, and the mill was found to answer admirably, grinding, in almost all weathers, at the rate of 20 bushels or 1120 lbs. of flour per hour, and that at a time when the vessel was steaming at 7^ knots or 8^ miles per hour, both the mill machinery and the ship being propelled by the same engines, which were constructed by Messrs. Robert Stephenson & Co., of 80 horses power. CORN-MILL MACHINERY. 139 Details of Machinery/. The elevator consists of a loner endless chain of small buckets formed of tin plate, and mounted at regu- lar distances upon a leather or canvas band passing over two pulleys inclosed within the cast-iron frames v, Y and the wooden boxes w, w. The uppermost of these pulleys is driven at a moderate velocity by a belt, and the buckets passing in succession the opening Y (which is kept constantly supplied with the material to be raised by means of an inclined spout) become each charged with a certain portion, which is carried up one side, and from which it falls through the spout X into the garner or the machine prepared for its reception. From this it •will be seen that the buckets, having dis- charged their contents into the spout x, descend empty on the opposite side, ready to receive or take up theii* respective load as they pass the feed-spout y, under the lower pulley. The lower part of the elevator is shown in fig. 261. It consists of two cast-iron Pig. 261, Fig. 260. 140 OX COEX :\IILLS. frame plates a, h, bolted together, about a quarter of an inch in thickness, upon which grooves are cast for the reception of the sheet-iron plates c, d, and e, /, which are bent to the shape of the frame plates, and inserted in the groove, forming, when the bolts h, k, are screwed tight, a neat and compact box. The creeper, fig. 262, is an archimedian screw worked in con- jimction with the contrivance just described, which is applicable to the raising of the grain or flour from a lower to a higher level. For horizontal transport modern millwrights make use of this apparatus, which is an application of a well-known principle for the abridgement of manual labour. This creeper consists of a Ficr. 262. Fijr. 263. long endless screw with a wide pitch and projecting thin threads, inclosed in a wooden box or trough, of dimensions slightly greater than its own diameter. It is made to revolve on its axis by means of a belt and pul- leys, at a velocity corresponding with that of the elevators, and, beinof restricted from movino- lonm- tudinally, the threads, or rather leaves, of the screw force the grain introduced at one end of the trough to the other. The ac- tion of the screw in the case of the creeper is identical in its na- ture wdth that of the endless screw in giving motion to a worm wheel. The material employed is Cci,st-iron ; the creeper is made in COEN-MILL MACHINERY. 141 6 feet lengths, each length being in the form of a tube 3^ inches in diameter, and about -^- of an inch thick, with broad leaves or threads cast round it, after the manner of an archime- dian screw. The thickness of the threads does not exceed -fj of an inch at the outer extremity. The different lengths of which the entire creeper is composed are joined together by short wrought-iron studs x, oc, fig. 264, forming also the journals on which it revolves. These are made with square tails fitted into similar holes formed in the Fie;. 264. centre of the small cylindrical blocks lu w, which are carefully turned on their exterior surfaces, and driven into the open ends of the pipes y y, figs. 262 and 263, previously bored to the same diameter. This con.struction at once insures a strictly rectilinear axis for the entire range, whatever may be its length. The arrow, fig. 262, indicates the direction in which a creeper, constructed in the manner shown in the general view, would propel the grain. The separator, fig. 265, consists of a wire cylinder A b, divided into partitions by a screw c, with long leaves and coarse thread, through which the wheat slowly travels and keeps falling by its own weight, as it moves forward from one extre- mity of the screen to the other. The space underneath the wire cylinder is divided into chambers by partitions. From e to /, in the first compartment, the wire of the cylinder is so close as only to admit of dust passing through ; from e to r/, in the second, the wire is arranged for only small wheat ; and from g to h, in the third, the large grains of wheat are freely delivered into the spout />■, from which they are conveyed to the wheat screen. Should there be any stones or large substances in the wheat, they are cast out at s. A whalebone brush p b, serves to free the machine from all grains of wheat which fasten themselves between the meshes of the wires. As fast as the brush wears away, its position is regulated and maintained by 142 ON CORX MILLS. the adjusting screws I m. The cylinder and the screw are con- nected together, and revolve at a velocity of 20 revolutions per minute. Fig. 265. The screening machine is constructed as shown in the draw- ing, fig, 266. The cylinders a h of these machines vary from '4 feet to 8 feet long. The annexed is a small one, 4 feet 2 inches long and 1 foot 4 inches' diameter, covered with 6 hj 8 wire gauze, and has an inclination of 1 in 2. Eings of wood e, /, g, |- thick and 2^ deep, are placed round the cylinder at distances of 4f inches. To bind the rings to- gether, horizontal planking is used, as shown at c and d, in the transverse section, by reference to which it will be seen that the cane brushes do not touch the wire gauze, but that -^ of an inch clearance is allowed. The brushes revolve in the cylinder at a velocity of from 350 to 400 revolutions per minute, and by this action the corn, which enters the machine by a v^^ooden spout through the opening I, is brushed ; the dust passing through the wire gauze falls into the close chamber K, whilst the corn travels to the end of the cylinder a h, where a spout m is fitted for its reception. On its passage from this CORN-MILL MACHINERY. 143 spout to the space o, it is exposed to the action of a current of air from the fan G, which clears it of dust through the aperture s. Fig. 266. The proper distance of the cane brushes from the wire gauze is maintained, as they wear away, by the screws t and v, and the shaft on which the brushes are fastened is adjusted by the 144 ON CORX MILLS. screws uiv; h is the dust-hole at the bottom of the machine, 12 inches square, tlirough which the dust is taken as often as necessary from the chamber K. By the door e convenient access to the machine is afforded, and the dusting and cleaning rendered easy. Fig. 267 is an outside elevation of the screening machine, wliich shows the cast-iron frame lined with wood. The screws Fiff. 267. w tu, which regulate the shaft on which the brushes are fixed, are screwed into projections a b cast on the frame, and by the slots and screws c, d, e, f, the whole of the brackets A b can be raised or depressed as necessity requires. In some mills, besides the separator already described, a smut machine is used. The corn enters the machine by the spout a, fig. 268, and falls upon the cast-iron plate b c, which, revolving with the shaft d, and the beaters e, f, g, h, k, /, at a velocity of 450 to CORN MILL MACHINERY. 145 500 revolutions per minute, throws the corn to the extremity of the cylinder m n, where it comes into contact with the beaters, which, together with the fan o', as the corn passes through, take away the greater portion of the dust and foreign matter. Owing to their not being surrounded by a wooden framing, these machines are placed in a closed room by them- selves. Fig. 268 represents a section of a machine of this kind ; the Fig. 268, cylinder m n is 1^ V diameter, by 4' 6'' long, covered with 6 by 8 wire gauze, and is surrounded at intervals of 9 inches by rings VOL. II. L 146 ON COKN MILLS. of iron p, q, r, s'. Inside the cylinder two arms of cast iron s and t are placed, and bolted on these arms are six pieces of iron, as shown in the cross section. The arms are keyed on the shaft d, which is driven by the pulley v, for the bearing of which circular rings a, /3, y, are made and fitted in the box w, and the whole is supported by the framework A, b. By the spout c, c, the corn is conveyed to the screening machine, or the millstones, and by the passage d the hollow grain and' heavy dust fall into the spout e, and the dust into a chamber at f. This description of smut machine is the one most in use at present, having completely superseded the American wheat screen. Another sort of wheat screen or smut machine has been patented by Mr. James Waltworth. In consists of a number of cylinders a b, c d, e/, g It, fig. 269, covered with wire gauze. The outer coating of wire gauze is Fig. 269. CORN MILL GEARING. 147 taken away from the cylinders c d, and ef, in order to show the internal cylinders also covered with wire gauze and grooved plates. These cylinders are supported by rings of cast iron fastened to the projections s, t, v, w, &c., on the cast-iron columns c, B, &c. The wheat enters the machine, which revolves at a velocity of 500 revolutions per minute, by the spout a; it then passes between perforated grooved plates in the first cylinder, like those shown at op, yz, in cylinder cd. After passing through these perforated grooved plates where it is scrubbed, r, the corn descends between the wire gauze of the internal and external cylinder where (the outward cylinder being stationary, and the internal cylinder revolving) it is exposed to a severer brushing, without, however, injuring the grain. Having passed through all the cylinders successively, it falls into the spout L, and on its passage to the part m, it is exposed in the box g to the action of a powerful fan f, which draws up all the light grain dust, &c., and ejects them at ii. By the cast-iron box E L, convenient access is afforded to the footstep m. The opening K, admits the air under the perforated plate for the fan. n is a pedestal for the fan shaft o, and t, a bracket which serves at its bearing. The fan is driven by the pulley P, which is connected by the strap Q with the pulley B, keyed on the shaft s. The value of this machine consists in the large amount of scrubbing surface over which the corn passes. Slight modifi- cations of this machine are made for Egyptian corn, which is first washed, and th^n run through the cylinders of the machine. The Framing. — A cast-iron standard or framing a, a, fig. 270, securely bolted to a stone foundation by two holding down bolts, encloses the principal part of the driving and adjusting gearing for each pair of stones. It is made in the form of an oblong box, and is traversed by two horizontal diaphragms or partitions, cast of a piece with it, the upper one for sustaining the footstep of the mill-spindle and its adjusting apparatus, and the lower for carrying the plummer block of the driving shaft. It is surmounted by a large bell-shaped casting b, b, called the cone, firmly bolted, by a flange at its lower end, to the standard, while the upper extremity is expanded, and terminates in a cylinder of a diameter somewhat greater than that of the 148 ON COEN MILLS. mill-stones, in which the lower (called the bed-stone) rests, and is secured within it. Two straight and broad flanges are cast at opposite sides of the cylindrical part, for the purpose Fig. 270. of bolting the cone to the beams of the mill, or to the same part of the framing of the contiguous pairs of stones ; while another circular flange passes all round, for sustaining the flooring. Three large openings are left in the upper part of the cone to give access to the interior, and it is provided with suitable arrangements for the reception of tlie several ad- justing screws required for the setting of the lower stone. CORN MILL GEARING. 149 Fig-. 271 represents a plan of the cone showing the openings and the number and disposition of the adjusting screws above alluded to. Fig. 271. TliG Stone Case and Feeding-Hopper. — Above the cone, and of the same diameter with the cylindrical part of it, is placed the stone case c, fig. 270, which surrounds the upper stone, and serves to confine the flour which is the result of the grinding. This is simply a cylinder of thin sheet iron, resting upon the stone floor, and having affixed to the top of it a ring of wood, on which the tripod for supporting the feeding ap- paratus is set. This cover is made open in order to admit the air freely between and around the stones during the process of grinding. A cast-iron ring d, fig. 270, supported by three malleable iron legs a, a, a, forms a sort of tripod in which is placed the hopper e, which receives the grain from the garners above, through the feeding-pipe or spout b, and sup- plies it to the stones by means of the feeding apparatus to be hereafter described. A piece of coarse wire gauze is placed in the hopper, to intercept any foreign body that may descend with the grain. An enlarged view of the ring d is shown in fig. 272. The Driving Gear. — The driving shaft f, is part of the line of horizontal shafting' which is common to the whole ransfe. 150 ON CORN MILLS. and receives its motion from the prime mover, generally through the intervention of a single pair of wheels. The ve- Fig. 272. locity of this line of shafting is usually from 70 to 80 revolutions per minute, with stones of the diameter of those in our examples. The different lengths of which it is composed are connected together by couplings of the same description as that described Fig. 273. and represented at fig. 213, page 81 of this work. The shaft F revolves in brass bearings, fitted into a plummer block G, fig. 273, bolted to a sole formed, as before noticed, in the standard A, Fig. 274. The strain of the shaft being entirely in a down- ward direction, this plummei'- block requires no cover, the journal being simply protected from injury by a slight brass cap. A large bevil mortice wheel h, figs. 270 and 274, working into the pinion i, on the mill-spindle, serves to transmit the motion of the shaft f to the latter. These wheels are made with the greatest possible care and accuracy, so as to work together very smoothly. The pinion is not fixed immovably upon the spindle, but is capable of sliding vertically upon it by means of a sunk feather. The Mill-spindle and its Appendages. — The mill -spindle CORN MILL GEARING. 151 J, J, fig. 270, is made of the best forged iron, accurately turned over its entire length; and rises perpendicularly through the standard a, the cone b, and the lower millstone. It is attached Fiff. 274. to the upper or running stone by means of a cast-iron piece K, figs. 270 and 275, called the Khind, which combines this function with that of regulating and delivering the supply of grain to the stones. It will be observed by the drawings, fig. 275, that it forms a species of universal joint, the small steel cross-head c c, on the top of the mill-spindle, fitting into corresponding bearings in the rhind, while the projecting tails d, d, cast upon it at right angles to the former, work in similar bearings formed of small cast-iron pieces sunk into the stone. By this arrangement it will be observed, that the connection between the mill-spindle 152 ON CORN MILLS. and the upper stone is complete, while at the same time it ad- mits of the free and unconstrained action of the latter against the grinding surface of the lower stone. The lower or fixed stone is perforated by a large square hole in its centre, into which the cast-iron block l, fig. 276, is firmly fixed by slips of wood and wedges. Into this block are fitted the three brass bushes e, e, e, which form the upper bear- ing of the mill-spindle. These are adjusted by means of the wedges /, /, /, the screwed tails of which pass downward through the ring g, fig. 277, and are regulated by thumb screws on each side of it. The large openings in the cone, before alluded to, afford access for the working of these screws. Small semi-cir- cular chambers are formed in the socket L, fig. 276, between each bush, and filled with hemp and tallow for the lubrication of the mill-spindle ; and the whole is carefully protected from dust by slips of sheet-iron screwed over it. The Millstones. — The diameter of the millstones most in use at the present day is 4 feet, and their thickness about 12 inches ; one half of this thickness is composed of French burr, a very MILL-STONES. 153 hard, though porous mineral, of a siliceous nature ; the other half is made up of plaster of Paris, In consequence of the Fig. 276. Fig. 277. difficulty of obtaining sufficiently large masses of the French stone, it is usual to construct the millstones in segments, which are cemented together, and the whole firmly bound by iron hoops passing round the circumference. The lower stone is, in the first instance, carefully dressed into a perfectly flat, plane surface, but the upper one is made slightly hollow for a small 154 ON COKN MILLS. distance from the central aperture, so as to allow the grain to be freely admitted between the stones. Being thus prepared, the circumference of the stone is Fig. 278. divided into 1 1 equal parts, fig. 278 ; lines are drawn from each division to the centre; these radii determine the limits of the grooves in each com- partment. A chord h' d , is then drawn, joining the boun- ding radii of any two com- partments ; this chord is, of course, bisected by the in- termediate radius j ct! , in d'. Divide the line dl c', into four equal parts in the points e' ,f, g', and from these points mark off, on the line d' cf, distances equal to the width of the groove to be cut, which is generally from 1^ to If inches wide, then draw through all these points of division lines parallel to the radius J a', terminating them in the radius J c'. These are the out- lines of the grooves, which are then to be cut into the stone, perpendicularly on one side, and obliquely on the other, so that each furrow shall have a sharp edge. The direction of the grooves being the same in both upper and lower stones, as they lie on their backs in the position proper for being cut, it is obvious that when the former is reversed and set in motion, their sharp edges will meet each other after the manner of a pair of scissors/ (as partially shown by the dotted hnes in fig. 278), and thus grind the corn more effectually when it is sub- jected to the action of the unbroken surfaces between the channels. The land, or portion of stone between each furrow, is cut like the teeth of a file with from 11 to 18 fine grooves to the inch, at an angle of about 45° with the furrows. A brush is placed on the side of the top millstone to clear the cylindrical cover of the flour at each revolution. Adjustment of the Loiver Stone.~lt is essentially important to the proper working of any pair of stones, that the grinding surface of the lower stone should be perfectly level, and that its MILL-STONE SPINDLES. 155 Fig. 279. centre should be exactly perpendicular above that of the lower bearing of the mill-spindle. To secure the former of these conditions, three pinching screws /i, h, h, figs. 270 and 279, are fitted into the cone, (that number being greatly preferable to four in adjusting the level of any surface), and, bearing against small slips of iron sunk into the stone, it can be raised or depressed by them to any required extent. Fig. 279, h, shows the screw for levelling the lower stone on an enlarged scale. The centering of the stone is effected by means of four pinching screws i, i, i, i, figs. 270 and 271, acting horizontally upon it. Fig. 279, i, shows this screw on an enlarged scale. To secure it against deviatino- from the truth after having been properly adjusted, all these screws are provided with jam nuts. Adjustment of the Mill-Spindle. — The lower bearing or foot- step of the spindle J, fig. 270, is also made capable of nice adjustment, both horizontally and vertically. The former is necessary in order to ensure the accurate working of the driving wheel and pinion, and the latter to regulate the pressure of the upper upon the lower stone, and to compensate for the changes produced upon both by the frequent dressings which their grinding surfaces have to undergo. The footstep k, figs. 270 and 280, which is of gun metal, is turned and fitted accurately into a cast-iron socket I, resting on the upper dia- phragm of the standard A, fig. 270 ; the hole into which it is inserted, and the annular recess by which it is sur- rounded, being made of somewhat greater diameter than the corre- sponding parts of the socket itself. Its exact position is determined and secured by the four radial pinching screws m, vi, m, m, fig. 281, passing through the ring and working in nuts fitted into recesses cast upon its interior surface, fig. 282. Fig. 280. 156 ON CORN MILLS. Fig. 281. Fig. 282. The footstep k, is not fixed immovably into the socket I, but is capable of sliding vertically into it. Its proper position in this direction is regulated by means of a strong wrought-iron lever m, figs. 270 and 283, having its centre of motion in the Fig. 283. back of the standard A, while its opposite end projects through a slot, and is raised or depressed by means of a screwed rod n, figs. 270 and 284, jointed to it, and passing through a project- Fig 284. Fi"-. 285. ing shelf cast upon the front of the standard. A small link or saddle n, figs. 270 and 285, serves to connect the lever with the footstep k ; the saddle being pro- vided with a square tail, which is inserted into a similar recess in the under side of the footstep ; by which means the latter is prevented from turning in its socket. Thus it will THE SILENT FEEDER. 157 Fig. 286. be seen that the entire weight of the upper stone and mill- spindle rests upon the lever m, and that the miller is enabled to vary at pleasure the pressure upon the grain between the stones, and consequently the degree of fineness of the flour produced, by simply turning the nut of the screw N, by means of the key o, figs. 270 and 286. Tlie Feeding Apparatus. — By the old process the stones were fed by a clapper, fixed on the top of the running mill- stone, striking the end of a shoe or trough fixed to the under- side of the hopper, through which the grain travelled, when slightly inclined,, into the eye of the stone, every time it received a blow from the clapper. An improvement on this primitive apparatus was effected by the introduction of the damsel, formed of an iron spindle with three blades which acted against the side of the shoe, causing a vibratory motion, and propelling the grain forward in a uniform stream into the eye of the stone, as shown at a, fig. 287. The damsel was a Fig. 287. great improvement on the clapper, and continued in general use until the centrifugal or silent feed was introduced.* * On its first introduction I had to contend against many opponents, who looked upon the new system of feeding as an innovation. Had it been a patent it would probably have come much earlier into general use. 158 ON CORN MILLS. In this arrangement, the supply of grain admitted between the stones is regulated by means of a cast-iron pipe o, figs. 270 and 288, open at both ends, the lower end being brought Fig. 288. into close proximity with the rhind, while the upper part encloses the pipe in which the feeding hopper E, fig. 270, ter- minates. It is suspended by means of a cast-iron lever p, which has its fulcrum in the small column 'p, fig. 270, depend- ing from the tripod d. A small chain attached to the end of the lever, and passing over a friction pulley at the bottom of the stone case, serves to connect this feeding apparatus with an ingenious little piece of mechanism Q, figs. 270 and 289, Fig. 289. DISENGAGING MILL-STONES. 159 attached to the standard, by which the miller is enabled to re- gulate the supply with the greatest nicety. This contrivance, as shown in fig. 289, consists of a small hand-wheel q, working between the cheeks of a double bracket bolted to the standard A. A small screwed pin forms the axis of this wheel ; it passes freely through the cheeks' of the bracket, but is screwed into the eye of the hand-wheel, and is prevented from turning with it by means of a feather inserted into the former, and fitting into a groove cut throughout the entire lengih of the pin, to the upper end of which the chain is attached. By this arrange- ment it is obvious that by turning the hand-wheel q, to the right or left, the small pin will be raised or depressed, and through the intervening mechanism, as shown in fig. 270, the size of the opening between the mouth of the feeding-pipe o, and the rhind cup, will be increased or diminished. On slightly raising the tube o, by the lever P, fig. 270, the grain slides along the surface of the cup or rhind k, which, revolving at a rapid motion, discharges the grain with tangential force over the Fig. 290. rim of the cup between the run- ner and the bed-stone. The grain, as it escapes from under the tube, flies off in tangents from the edge of the cup, and forms a beautiful series of cui'ves, as shown in the drawing, fig. 290. At first this system of feed- ing, like all other improvements, met with opposition from the millers ; but the regularity of the supply, and the absence of noise, soon con- vinced them of its advantages, and paved the way for its general application. TJie Disengaging Apparatus. — The driving pinion i, fig. 291, is fitted upon the mill-spindle, so as to be capable of sliding up and down upon a sunk feather. \NTien fully engaged with the wheel H, fig. 270, it rests upon a collar formed on the upper sur- face of a large brass nut j, fig. 292, fitted to a screwed part on the lower end of the spindle, and capable of being fixed by a jam nut, by which the miller is enabled to keep the pinion invariably iu its proper position with regard to the wheel. 160 ON CORN MILLS. independently of the position of the spindle, which, as we have before had occasion to remark, requires to be slightly lowered Fig. 291. every time the stones are dressed. When properly adjusted, the pinion is secured to the spindle by a taper key. Fig. 293. Fig. 292. It is, however, necessary to throw each pair of stones, periodically, out of gear with the general range, to admit of their being dressed, &c. For this purpose the tapered key is removed, and the pinion raised out of contact with the teeth of its driving wheel, by means of a species of jack or lifting apparatus attached to the standard, the component parts of which we shall now briefly enumerate. A cast-iron ring k, figs. 270 and 293, supported upon two upright rods r, r, is brought in contact with the under eurface of the pinion by turning the hand-wheel s, which is screwed upon its axis t, and carries with it in its ascent the cross-head s, into the ends of which the lower ex- tremities of the rods r, r, are inserted. The screw t is fixed into a socket cast upon APPARATUS FOR LIFTING MILLSTONES. IGl the under surface of the lower diaphragm of the standard, and the connecting rods r, r, which pass through holes formed for their re- ception in both diaphragms ; being set in a diagonal direction in order to clear the lever m, and other important parts -^'S- 294. of the machinery. Fig. 294 is a plan of the hand- wheel and cross-bar. On turning the hand- wheel in a contrary direc- tion, the weight of the pinion again brings it into its working position. The Stone-lifting Apparatus. The portable crane or lifting apparatus used for raising the upper stones from their beds, and depositing them on the floor of the mill when they require to undergo the process of dressing, is shown in fig. 295. It consists of a strong malleable iron arm t, t, bent into a form nearly approaching to a quadrant; the lower end works in a cast-iron step v, inserted into the stone floor, while its upper extremity is supported by a strong rod u, fitted to rotate upon a stud u, fixed into a cast-iron plate, bolted to the beams which support the floor above. The fixed centres, u and V, are so situated that the machine shall command two contiguous pairs of stones, and the end of the rod u is made of such a form as to admit of its being easily disengaged from the stud ; when the entire machine may be removed. A strong screw V, passing through the arm t, and worked by means of a nut formed into a double handle, carries at its lower end the two connecting links w, w, which are attached to the stone by two studs temporarily inserted into it at points diametrically opposite. The links w, w, are bent so as to admit of the stone being inverted while it is suspended in the lifting machine. The rimning stone is retained in its place in the mill simply by its own weight ; it is, therefore, only necessary to raise it out of its bearings when the grinding surfaces require examination or repair. The sack teagle is very simple, and will be readily understood VOL. II. M 162 ON COEN MILLS. from the drawing, Plate III. It consists of a barrel r', provided with a rope of sufficient length to reach to the lower floor of the mill, and fitted to revolve in bearings attached to the roof; it receives motion, when required to be brought into action, from Fig. 295. a belt connecting the pulley on its axis with a shaft c', worked by the engine. The length of this belt is so adjusted that the sack teagle may remain at rest, or be set in motion, accord- ing as the long lever (the action of which is to tighten or relax the belt as may be required) is raised or lowered. In DRESSING MACHINES. 1G3 the floors of the mill are formed square hatches or openings, through which sacks, &c., may he admitted ; and the rope of the sack teagle passing over a guide pulley situated im- mediately above the centre of these hatches, thus affords a ready means of raising sacks or any heavy articles to the dif- ferent flats of the mill. The Dressing Machine. After passing the millstones, and having been carried by tlie creeper and elevator to the third storey of the mill, the corn enters the dressing machines ; it is here subjected to the last process, and is ready for market. Fig. 296 represents a dressing machine on a scale ^ inch = the foot, the cylinder 5'.2'' x I' A", is of wire cloth, from a to b is FiK. 296. in general up to No. 70 wire gauze, from 6 to c is of No. 48 and 50, and c to tZ of 30. It seldom happens that wire cloth of M 2 KU ON CORN JIILI,S. No. 120 wire gauze is used in those machines for the first division, from a to h, unless it be for the finer description of flour. An inclination of 3 in 8 is given to the cylinder, and it makes from 560 to 650 revolutions per minute. Eings of wood, |" thick, and 2^" deep, are placed roimd the cylinder at intervals of 4f inches, and the whole is bound together by horizontal planking i" by 2\". The same contrivance is used for the adjustment of the brushes and the spindle as in the screening machine ; the brushes, however, in this instance touch the wire gauze, and are made of bristle. riff. 297. The ground corn, introduced by the spout e, is brushed first over the finest layers of wire from a to h, then over the coarser from h to c, and lastly over the coarsest from c to d, and is denominated firsts, seconds, and thirds, according as it passes through the first, second, or third divisions of the machine. That portion of the ground corn which is too coarse to pass through any of the meshes falls out at the end of the cylinder and is called bran. DRESSING MACHINES. 1G5 Some improvements, of late, have been effected in the con- struction of wire-dressing machines, by substituting an iroa instead of a wood framing ; by augmenting the speed from 32 to 500, and even 650 revolutions per minute, and by giving an inclination of 45° instead of 20° to the cjdinder. Fig. 297 represents one of these improved ii'on dressing machines. In its general construction, it somewhat resembles the one already described, fig. 296. In this machine the ground corn enters the cylinder b b, by the hopper a, containing a patent feed apparatus, which regulates the feed, and thus prepares it for passing through the meshes of the wire cylinder. The internal brushes are secured to the spindle as those in the previous machine, fig. 296, but with a different arrangement for adjustment. The speed of the driving shaft is quickly reduced by the spur wheels, which gear into a wheel on the circumference of the cylinder, thus causing the cylinder b b slowly to revolve. The pulley d is connected with the pulley e by means of the strap f, which causes the external brushes G G to revolve, and thus keep the wire cylinder from being clogged up. By an ingenious arrangement with an eccentric, the brushes are lifted off to allow the cross bars h h, K K, to pass without injuring them, and are reinstated in their position as soon as ever the bars are clear. Ey twisting the strap, these brushes are made to revolve in a contrary direction, and thus prevent the bristles from taking a permanent set in one direction, and from wearing away un- equally. The space under the cylinder is divided into three partitions, or hoppers, by movable boards, and the distance between them is increased or diminished at pleasure by the hand-wheel l. As in fig. 296, that portion of the meal which does not pass through the wire cloth falls out at the end of the cylinder. The bolting machines are on the Swiss and American principle. Fig. 298 is an end elevation of a bolting machine, with two cylinders, and fig. 299 is a longitudinal section on a smaller scale. The cylinders K K are from 24 to 26 feet long, and 3 feet diameter, and make fi-om 20 to 22 revolutions per minute. At distances of about 4 feet, radiating rods are inserted in the wooden shaft, which forms the reels of the bolting machine, to support the 166 ON CORN MILLS. silk covering through which the flour has to pass. This hex- agonal wooden shaft terminates in iron pivots which have their bearings in the plummer blocks l, l, bolted to a cross piece of cast-iron m m, which is bolted to the wooden frame- Fig. 298. llllllliiil:lli!l!lllllllllilllllllill!l!llilllllllillillllllll|!!g^Sl.illliill!illllllii;^ work N N. The machine is driven by a cross shaft o, having two bevil wheels, p p, keyed upon it, which gear into corres- ponding wheels keyed on the driving shafts of the bolting cylinders. The cross shaft also gives motion through the inter- vention of the strap q to the pulley e, which drives a small toothed wheel s, gearing into a wheel T, keyed on the creeper Fis. 299. BOLTING MACHINES. 1G7 shaft u, which carries the flour along the trough under the cylinders or reels. It will be observed that the cylinder cover, V V is grooved into the end of the cylinder, and moves with the machine, whilst the cover W W is stationary : this enables a con- stant supply to be given to the machine without waste. The meal travels from the elevators along the creeper a a, and enters the bolting machine by the hoppers b b ; here it makes a progressive onward motion, rising and falling by gravi- tation from the sides of the reel till the flour has passed through the interstices of the silk and the bran delivered by the spout c at the end of the machine. The flour, after passing through the silk, falls upon the boards e e fig. 298 and f f fig. 299, into the creeper h; and in travelling along this creeper, it is received into bags by the spouts G G G. Should any of the meal have failed to pass into the bolting machine, it is carried on to the spout h' fig. 298, which conveys it to the elevator from which the creeper A is supplied. The finest flour, chiefly used for confectionery and biscuit-making, is dressed and pre- pared in this way. The great advantage of this class of dressing machinery is that the silk-bolting machine dresses the flour direct as it comes from the millstones, as the process is slow, and by the repeated rising and falling of the meal in travelling from one end of the cylinder to the other, it is sufficiently cool for immediate use, or ready to be hoisted above by the sack teagles, to be sacked for the market. Messrs. John Staniar and Co., Manchester Wire Works, who supply this class of machinery, have lately constructed the dressing and bolting machines, with an improved feed. The meal is conveyed into a hopper with inclined sides, over which a rake slowly revolves, and as the meal travels several times round before it arrives at the feed-spout in the centre, it is ex- posed to the action of the air, and freed of the greater portion of its moisture. A piece of coarse wire gauze is placed at the top of the spout to intercept any foreign particles which may accidentally have got into the meal. 1G8 ON CORN MILLS. REFERENCES. A A, the standard or lower framing of the grinding machinery. B B, the cone or upper framing. c, the stone case, of sheet-iron. D, a cast-iron ring supporting the hopper, carried upon a, o, a, three wi'ought-iron legs, resting upon the top of the stone case. E, the feeding hopper. h, a pipe for supplying grain to the hopper from the garners above. F, the main driving shaft. G, plummer-block of the shaft F. H, a bevil mortice wheel, conveying the motion of the shaft f to I, the pinion of the mill spindle. J, the mill spindle. K, the rhind of cast-iron by which the spindle is connected with the upper stone. c, d, the bearings of the universal joint formed by the rhind. L, the bed-stone box for the upper bearings of the mill- spindle. ef, bushes and wedges for adjusting the bearings. g, a thin cast-iron plate, by means of which the wedges /, /, are adjusted and fixed. //, h, /j, pinching screws for adjusting the level of the lower millstone. i, i, I, pinching screws for centering it. j, a large brass nut for supporting the pinion 1. kf footstep of the mill spindle. Z, cast-iron socket for the footstep k, m,m, pinching screws for adjusting the socket I. n, the saddle or link connecting the footstep k Avith M, the great lever for supporting, and adjusting the mill-spindle. N, 0, screwed rod and key for Avorking the lever Ji. o, the movable feeding pipe, of cast iron. r, lever for adjusting the pipe o. p, small colmnn forming the centre of motion of the lever p. Q, q, apparatus for regulating the feed. R, a cast-iron ring for raising the driving pinion out of gear with the wheel. S, a cast-iron cross-head, being part of the same apparatus. r, r, upright rods connecting the cross-head s with the ring R. s, s, t, hand wheel and screw for workinor the disensrasrinfr sjear. T, u, V, w, the several parts of which the stone-lifting machine is com- posed. M, V, the centres of motion on which it turns. BALANCIXCi MILLSTONES. 169 X, the lower eleA'-ator frame. Y, Y, the creeper of cast-iron. IV, X, blocks and studs for connecting the adjacent lengths of the creeper. I/, the brackets in Avhich it revolves, z, z, the creeper box, of wood. Before closing the treatise on flonr mills, it may be inter- esting for the practical miller to know that an ingenious contrivance for balancing the running millstone has been successfully introduced by Messrs. Clarke & Dunham, of Mark Lane, London. JNIost persons connected -with grinding wheat are aware that millstones are built of blocks of French burr, varying in density. These blocks are cemented and held firmly together by iron hoops, as already described ; and the back of the stone is filled in with odd pieces of burrs, and backed up with plaster of Paris. The centre or balance-irons, by which the stone is suspended, are then let into the runner ; it is immaterial what sort of iron is used for balancing, as any description will do. The usual custom is to suspend the runner on the stone spindle, and balance it with reference to its gravity alone, thus producing a standing balance by adding the required quantity of lead to produce a stationary equilibrium. This was generally thought enough, and the stone considered fit for work. Had the miller, however, raised the runner to an elevation of half-an-inch from the bed-stone, and rotated it at a speed of from 120 to 130 revolutions per minute, the runner in motion would have dipped or 'wabbled' to the extent, on the average, of a quarter of an inch. The effect of this tilting motion when the stones are at work, is to cause unequal pressure and unequal action upon the face of the stones in contact. The cause of this is the effect of the unequal density of the millstone as a whole, causing in motion an unequal centrifugal action in proportion to the denser parts preponderating above or below the plane of suspension. In order to obviate this evil, there is introduced into the back of the runner four balance boxes, as shown in fig. 300 at b b. These boxes vary in depth from three to five inches, according to the 170 ON CORX MILLS. thickness of the runner; the boxes are fitted with annular weights capable of being adjusted higher or lower, by means of the screws d d, which pass down the centre of the weights. The number of the weights depends on the number required to pro- duce the perfect standing balance. From this it will be seen that the standing balance must be first attained, and then, by raising or lowering the weights in the balance boxes, the running balance is perfectly effected. This is not done liy one adjust- ment only, but by a series of adjustments. Having effected a standing balance, the stone is set in motion, and the dip is found to be on a particular quarter ; the stone is then stopped, and the weights in the box opposite to where the dip is are raised higher above the plane of suspension so as to neutralize the variation of the dipping side. This being done, the stones are again set in motion, and the same operation is performed until a perfect balance, at any velocity, is attained. The great advantage of this arrangement is that the weights cannot shift, and the same balance is maintained in good order, and only require altering with the ordinary wear and tear of the stones. 171 CHAPTER III. COTTON MILLS. In our attempts to illustrate the improvements that have taken place in mills and mill-work we have endeavoured to give in detail the present improved state of the machinery for grind- ing corn, and the next — after what is generally called the staff of life — is the factory system for the manufacture of cotton. Of all the manufacturing interests which the industrial resources of this country present, this is probably the most important, not even excepting the iron and coal trades, and we may readily be excused if we briefly glance at the increase and immense extent to which this manufacture has attained until suddenly arrested by the unnatural war now raging in America. It will be in the recollection of most of our readers, that for the last seventy or eighty years, the mills of Lanca- shire and those of other parts of Europe, depended almost entirely for their supply of cotton upon the southern states of America, and that the extension of the trade grew up with the facilities of obtaining the means of supply; and although India, Egypt, and other countries, of late years cultivated and exported cotton, yet the chief dependence of Lancashire and other parts was upon the American states. The present mise- rable war has, however, cut off those supplies, and hence follows the distress and misery which has from this cause overtaken our once comfortable, willing, and industrious population. Our business, however much we may regret this circumstance, is not with the growth or supply of cotton, but its manufacttu'e, and we have now to describe the improved methods and systems adopted for giving motion to the various intricate and ingenious machines now in use. 172 OX COTTON MILLS. Until of late years, nearly the whole of our cotton mills were built from five to eight stories in height, with a succession of flats or floors in which the different processes were carried on. Generally speaking, the ground or first floors were appropriated to carding, drawing, and roving, with a separate building for the opening and blowing machines, and these constituted the preparatory process. The rooms above were invariably set apart for spinning, by mules if for fine yarn, but by throstles and mules conjointly if for coarser numbers. This w^as the state of the factor}^ system thirty years ago when adapted exclusively for spinning, but the introduction of the power loom and self-acting mule gave a new character to the dimensions and form of factory buildings. In the first instance, it was found that power looms worked better on the ground-floor than those on the upper stories, and that tlie yarn required a certain degree of moisture to weave freely, which could not be obtained from the heated and dry floors above. These properties peculiar to the ground-floor led to the shed principle, and there is scarcely a cotton mill now in the kingdom where looms are employed that has not a shed attached to the lower story on a level with the ground-floor. Again, it w^as found after the introduction of the self-acting mule that one man could work, wdth the assistance of two or three boys, 1,600 spindles with as much ease as he could work 600 spindles by the hand mules. This led to mills of double the width of the old ones, the former reaching from eighty to ninety feet wide. The spinning mills of the present day are therefore more like square towers or large lanterns, ^\ith considerable architectural pretensions as compared with the uncouth build- ings we have already described. To these square buildings it is usual to attach a weaving shed with all the requisite ware- houses and appurtenances for carrying on that additional de- partment of the manufacture. In order to exemplify our description of a cotton mill, with the steam-engine and transmissive machinery by which it is kept in motion, we might have chosen some of our largest establishments upon the principle referred to above ; but having constructed mills for the colonies on a different principle, we have selected for illustration one of those erected in India, DESCRIPTION OF COTTON .AIILLS. l?.-? where the whole of the machinery is on the ground floor, and where it is covered by a light roof on the principle of the weaving shed for looms. Messrs. William Fairbairn & Sons have built several of these mills for the Bombay Presidency, and the whole of the machinery being open for inspection can the more easily be traced from the opening of the cotton bales to the finished cloth on the opposite side of the mill. Description. In the annexed plan and sections it will be observed that the building covers a large space of ground, and is chiefly adapted for the country or small towns where land is cheap. In large cities such as Manchester, buildings of this description are seldom erected, owing to the high price of land and local taxes, from which the country is free ; we have there- fore most of our cotton mills in the surrounding districts, depending on Manchester as a centre and ready market for the sale and the export of yarn and cloth. The mill to which we refer, shown in plates V. and VI., was built for India, and is now in successful operation some short distance from Bombay. Plate VI. is a plan of the buildings showing the position of the machinery and the steam engines at a. The main shafts and gearing are supported on stone or brick pillars through the whole length of the building, receiving in their passage motion from the large pinion at b, which works into the fly-wheel, distributing it to the different Hues of shafting on each side. The steam is supplied to the engines by six boilers, 5 feet 9 inches diameter, and 32 feet long, with internal flues. The engines are each 80 horse-power, collectively 160 horses, 6 feet stroke, 26 "8 strokes per minute, and are calculated to work to the full extent of 600 indicated horse-power. The main shafts, which receive motion from the fly-wheel, make 80 revolutions per minute^ and are 8 inches diameter for a distance of 70 feet over the throstles and mules, and for a fvirther distance of 35 feet towards the cards, they are 6^ inches diameter, when they gradually taper in both directions to 5 inches at the end over the cards, and to 4^ inches over the looms. The cross shafts over the power-looms are 2^ inches diameter, tapering to 2 inches at the end. The cross shafts over the throstles and mules are 3-|- inches diameter, tapering to 2^ inches at the 174 OX COTTON MILLS. extreme end. Over the slubbing frames and cards they are 3 inches diameter, tapering to 2 inches, the same proportion being observed in the ratio of the power delivered in other parts of the mill. The cotton is taken from the cotton store, plate VI., and is mixed and sorted for the opening machines at G, where it is thoroughly cleaned, and driven about at great velocity, and freed from husks or seeds where it has not been properly ginned. From this it passes in a fleecy form to the scutchers h, where it is carefully spread upon a travelling cloth in front of the machine, and is carried forward to fluted rollers, by which it is conveyed in uniform thickness to the cylinder containing the beater with three or four arms, which makes about 1,600 revolutions per minute, or travels at the rate of 5,000 feet in the same time. Here it is driven forward into a cylindrical wire case, where it meets with a strong blast of air from a fanner which blows off all the light dust, whilst all the heavier earthy particles fall through the meshes of the wire into a re- ceptacle below prepared for that purpose.* Most of the improved blowers have two beaters, so that the cotton undergoes a thorough cleansing and opening before it is drawn from the wire cylinders and wound on the large bobbins or beams which form it into a lap ready for the cards. From the blowers the laps are conveyed through the door a to the cards, where the object is to clean and straighten the fibres and lay them parallel to each other. This is accomplished by unwinding the laps as they come from the blowers by fluted rollers which bring the cotton in contact with the teeth of the large carding cylinder and the covering flats also lined with teeth. In this way it is carded as the cylinder revolves, but not without being intercepted by the teeth of the flats and rollers, which nearly touching the main cylinder, the cotton is unable to pass without being combed and the filaments straightened in the direction of the two teethed surfaces as they meet each other. After passing through a succession of these flats and rollers, it is taken from the main cylinder by the doiBBng cylinder, which latter is finally stripped or cleared by a piece * The scutclier, or blowing machine, is the counterpart of the corn-thrashing machine invented by Andrew Mickle of East Lothian. !n^zi C3zr ^jf »> ofj. HEW TAIL §F: W(Er SOMFAF YAP.1 WAIE HOUSE E N 1 H a:j i: t ^ ^^^ " THE BLOWER AXD CARDS. 175 of thin steel, reciprocating by a crank motion on the surface of the cylinder, which forwards the cotton in a fine transparent sheet through a tube to the drawing rollers, where it is wound in circular coils into a can in the shape of a narrow band called a sliver. From the cards it is removed in the cans, when filled, to the drawing frames, which consist of a series of rollers on cast iron frames, in the line shown at 1 1 in front of the cards, and these rollers are so arranged that the front rollers run about four times the speed of the back ones, and from this increase of speed, it will be seen that the back rollers, whilst they are delivering at a uniform rate, the front ones are rapidly dra'wing out the fibres and delivering them in a form greatly attenuated to a much smaller sliver than that which first passed between the back rollers. These rollers require to be placed at the proper distance from each other, in order to correspond with the kind of cotton used, and the length of the fibre or staple, as it is frequently called. The object of drawing is to render the whole of the fibres as smooth and parallel as possible, and in the process of drawing as many as from five to six or more slivers in cans are run into one pair of rollers from the cards, and these again are frequently multiplied, drawn and redrawn, according to the quality of the yarn required, before they are fit for the slubbing or roving frames, which is the next process. The slubbing or roving frame is one of the most ingenious contrivances in the cotton trade, as it not only draws the fibre and elongates the sliver on the same principle as the drawing- frame, but it gives it a certain amount of twist, and "udnds it on a bobbin. For a long series of years this was a difficult process, as the delivering and the twist being the same at all times from the rollers, it requires to be wound on the bobbin one layer upon another, neither too hard nor too soft. If the former, the roving will not wind off the bobbin without breaking; and on the other hand, it must not be too soft, otherwise the fault would be equally objectionable as regards the quantity the bobbin should contain. The great secret therefore is to have it neither too hard nor too soft, but a medium degree of tightness, calculated to hold the exact quantity, and unwind itself freely one layer from off the surface of another, without risk 176 ON COTTON MILLS. of breakage. This would appear to be a desideratum (in every description of spinning), and to obtain this object with accuracy- many ingenious contrivances have been adopted, amongst which we may enumerate sliding straps on conical drums, calculated to the increased circumference of the respective layers as they are wound on, and thus to gain the required degree of tension and compression, as the bobbin continued to increase in dia- meter, or as each superincumbent layer was wound on. The most important improvement of the roving frame was, however, accomplished by the introduction of the differential motion, which beautiful piece of mechanism effected the object of retarding the motion of the bobbin in the ratio of the increased diameter as it continued to enlarge. This motion gave great exactitude to the process, and enabled the spinner to prepare his rovings with a much greater degree of precision, and in shorter time. After roving, the cotton undergoes a precisely similar process, by passing through what is called a Jack or a finer roving frame. In this it is again drawn with additional twist, and again wound on to similar but smaller bobbins, ready for spinning into yarn, either by the mule or the throstle, as the case may be. The above description completes, as far as oiu* limits will admit, the preparatory process, until the rovings are in a con- dition to be handed over to the spinner, to be converted into yarn. Before describing the subsequent processes, we must, however, advert to a most ingenious machine for combing the cotton in place of carding it. This machine was introduced into this country some years since from Alsace, in France, and its operations are performed with such exactitude and iDrecision, as to enable the spinner to produce a superior quality of yarn from an inferior quality of cotton. This machine has received great improvements since its first introduction, from the hands of Messrs. John Hethrington & Co., who have changed several of the motions, introduced others, and rendered it available for the finer descriptions of yarn. It is also extensively used in the preparation of wools of every description, but more particularly those of the alpaca, mohair, &c., as also in the preparatory process for flax, to which we shall subsequently have to refer. THE THROSTLE AND MULE. 177 To those familiar with tlie manufacturing districts the process of spinning is well known, but to the general reader who is not acquainted with those districts, a short account of the two different processes may not be uninteresting. There are two modes of spinning, one by a machine called the throstle, the other by the mule. During the early stages of cotton spinning, the cotton was carded and formed into slivers or rovings by hand cards. They were then placed on a wooden frame behind a row of spindles, fixed in a moveable box, which travelled on wheels, and these again received motion from a wheel and band, and the rovings which passed from the board behind, and delivered by rollers to the spindles, were held fast as the spinner drew the spindles from the rovings to the extent of the stretch ; and thus by consecutive movements the rovings were stretched and twisted, and every time the travel- ling frame was pushed back to the rovings, the j'^arn previously spun was wound upon the spindles. This was the only method in use before the time of Arkwright, who introduced the cylindrical cards and the water frame, or, as it was subsequently called, the throstle, the noise of the numerous spindles imitating the notes of that bird. It was also designated the water frame, from the circumstance that it could not be worked by hand, but required the power of water to give it motion. The next process is the throstle, which is on the same prin- ciple as the roving frame, but with this difference, that the spindles are smaller and more numerous, and range in rows of 150 or 200 on each side of the frame. It has also this peculiarity, that the bobbin which re-winds the yarn as it is spun is not regulated by the differential motion, but the thread, as it is drawn and twisted from the rollers, is wound on by friction as the frame in which the spindles are fixed rises and falls the length or depth of the bobbin. In this operation it is not necessary to wind the thread on to the bobbin slack, as there is no danger of the layers separating, and the friction given to the bobbin is therefore sufficient to fill it hard and tight. The rovings are also carried to the mule, which is a totall}'' different machine to the throstle ; it has no moveable frame or spindles with bobbins rising and falling; in fact, it is more VOL. TI. N 178 ON COTTOX MILLS. like the spinning jenny, with a travelling carriage which contains the spindles, and stretches out from the beam or stationary roller frame after the manner of the jenny already described. It, however, combines part of the throstle as well as the jenny, and hence its name of the mule. The mule as left by Crompton possesses many advantages that do not belong to the water frame. It can spin yarn of any degree of softness, and of the finest quality ; and since it was made self-acting, it forms its own cop on each spindle, and puts up the carriage, which on former occasions had to be done by hand. These are considerations of vast importance in spinning ; and the mule has now attained such perfection that 1,000 spindles can be worked in one carriage with the same certainty and ease as one-third the number could formerly be worked by hand. There is another peculiar property in the mule, and that is the double twist in fine numbers which the yarn receives after the full extent of the stretch is made. When the spindle carriage arrives at this jjoint the rollers become sta- tionary, the motion of the spindles is increased, and the twist required is given according to the quality or purpose for which the yarn is intended. I believe the introduction of the double twist motion is due to the late Mr. John Kennedy, one of our earliest and most successful mule spinners. Having thus traced the different processes from the bale of cotton to the yarn, our next duty will be to notice the opera- tions of weaving from the yarn into cloth. In our endea- vours to accomplish this it will be necessary to glance at the state of the manufacture as it existed previous to the intro- duction of the power loom, and to show the advantages attained and the enormous increase which these inventions have pro- duced. From the earliest historical period, the hand-loom has been in use for the purpose of weaving. That of the Hindoos and all other nations have been of the same character, and until the improvement of the flying shuttle, introduced by Kay, we may consider the loom a primitive and unchangeable machine. It is upwards of thirty years since the power-loom was first in- troduced. After repeated attempts by Major Cartwright, Mr. Shorrocks, and others, to render it available and self- WINDIXG AND WARPING. 179 acting, it fell into other hands. These attempts were at first discouraging, but after repeated changes, suggestions, and im- provements, it ultimately succeeded in producing a cloth more uniform in character and superior in quality to that of the hand-looms. The result of these improvements was a total change in the cotton manufacture. The hand-looms were thrown out of use, and the hand-loom weavers, who were un- able to meet the new state of things, were thi'own out of work, and suffered for many years the greatest and most distressing privations. By this transfer from hand to power weaving, the whole system of manufacture was changed, and the manufac- ture of yarn into cloth was no longer carried on in the domestic cottage, but became a part of the factory system. Large shed buildings were erected for that purpose, and the weavers, chiefly girls, were employed under regulations the same as those in the other parts of the mills. Before yarn can be woven into cloth, four distinct processes have to be gone through ; viz., warping, winding, beaming, and dressing - — to prepare the warp for the loom. The first of these, the warping, consists of a large vertical reel, on to which the yarn is wound from the bobbin in measured lengths, several of which, when put together, constitute the warp. It is then, for some qualities of cloth, sized or run through a cistern of liquid flour and water, at nearly the boiling temperature, and from this through rollers which squeeze out the surplus fluid, and leave the yarn saturated ^vith the glutinous substance of flour and water called size. In this state, when partially dried, it is transferred to the loom, where it is woven into cloth. The other process requires more careful manipulation, as the warps have to be formed by winding the yarn from the cop, if it be mule yarn, and from the bobbin if throstle, on to a roller called a beam, and in its passage it is run over a roller about twenty inches diameter, through the divisions of a reed formed of wire, to separate the threads and lay them parallel on to the roller beam. This done, four or six of the first windings are united on the dressing machine, k k, "where they are again passed through reeds at each end, and finally wound upon a large bobbin or beam N 2 180 ON COTTON MILLS. ready for the loom. ' In its passage from each end of the machine, it must, however, be observed that it is well brushed or dressed with a pulp of prepared flour and water, which is laid upon the warp, as it passes from the rollers at each end to the beam at the top of the machine, ready for the loom. The power-loom, although simple in its operations in the first instance, comprises at the present time many important improvements for the manufacture of twills and figure weaving. The revolving shuttle-box, and the changes in colour and form that may be effected, enable it in many cases to compete with the jacquard loom. Many of the beautiful fabrics of mixed goods are woven in this manner, and, judging from what has already been done, we may reasonably look forward to still greater improvements in the quality, as well as the quantity of cloth produced. It might have been desirable to have noticed the progressive increase of this important branch of industry ; but when it is known that a sum exceeding 70,000,000^. sterling represents its annual value, we have said sufficient to impress the reader with a desire for its maintenance and cultivation. We close the chapter on cotton mills with a list of the most approved speeds of the different machines, and a list of wheels, speeds, &c., as now in operation in the mill of the Oriental Cotton Spinning Company : — Speeds OF Machines. Description of Machine. Diameter of Pulley. Number of Revolutions per Minute. Opener or beater Scutcher Rollers inches. 12 7^ 21 800 1,600 270 Cards Grinding machines 18 12 130 200 Drawing fi-ame Slubbing „ Roving „ Throstle „ Winding „ 12 13 11 10 9i 226 235 415 562 180 Beam-warping . Tap leg-sizing . 13 50 210 Mules 16 232 Looms, 1 wide . Looms, 1 wide . 12 11 140 160 SPEEDS OF SHAFTS, ETC. 181 :s| -2-5 ^-^ S 6 "'^ s a 13 H CB cS oms. inning, ving an awing a rding fr rding fr ener. cu tellers cutcher. :utcher. hine. C&.O'-CJ-BjilCOOJSl' . O 3 — •MfH'CaoO.o-'-' Oal =* 3 C i a. c o 3 ain shaft. OSS shaft over nter shaft for )ener. unter shaft fo: atchers. Hers on doulil Hers on single rostles. ules. ving frames. nbbing. ■awing. rds. inding machin nding machin( 3ms, ^ wide. oms, 1 wide. ■ani-warping. p leg sizing m > as § 5-8 g 2 g:2 S g-^-S S Sd?^^^5 P4 33 » a: so C ■ 2 .2 .2 'o "o "o > > > %^ U li T* "^ "* 000>-COO>.'5 0'M>C1>0 00-*'OOCiO© CO Oi (O m t^ Oi rHOC0OI:^I^C0C0.-iM(MC0(MC0-*50-l,-lC 2 1— 1 .-H ^ ,-1 r-< Q « 5 .t;t-^(M^rHC^o -* 2 -*COOOOOeoO(^^^Oco^DOOF^^eo■*-^■SOOOO "o (N000000000000r~.-llr^00r^COCDCOCOCOt^!M rtC<0r-ICOrti-HrHrH(M(Mrt.-lrt,-lr-rt,-|.-l iZ rt > Q OJ «lt«t(MH'M rtl* -+M -lOl ->|M ttl-O-^l* -^ CTjiOt^OOOCOOOOt^Ot^CCOOOt^^^l^t^'— lOOOi— 1 s - r-H f-C ,-H rt ■rCeO^-*-*COCO00(MCO!N(Mr-<'M(Mr-l^r-(.-H^ -Hrt ^ (5 - C-l '^ , a -< m !>.•« .^ "^ ~. !~ «^ V^ ^~4J~.» S S c S,i> c ^ s J J^-^ (: ) Spur Bevil Morti Puli'e 182 CHAPTER IV. WOOLLEN MILLS. The difiference between cotton and sheep's wool is that the one is a vegetable and the other an animal substance, and the latter being dissimilar in its characteristic properties requires a different treatment in the manufacturing processes. The nature of the fibres of sheep's wool, which curl and hook into each other, is different to most other fibrous substances ; some of the early- preparatory stages in its manufacture into cloth, however, are the same as in that of cotton wool. The peculiar properties of some of the animal wools is their tendency when worked to entwine the fibres, so as to form a species of cloth called felt, without the aid of spinning and weaving. Hats, horse cloths, and other descriptions of clothing, are made in this way, and that by a process called wliipping, which separates the fibres by the vibration of a piece of cord or catgut, drawn tight over the extremities of an elastic bow. With this instrument the fibres are separated by a jerking motion of the hand, and fly off in fine flakes into a receptacle ready for use. It is then worked into a sort of pulp, in a vessel of hot water, to the required thickness. The same principle is observed in fulling blankets, broad cloth, and other fabrics of a similar kind ; the only difference being that the former is done by hand in a vessel of hot water, and the latter by the stocks or fulling mill. It is to this latter, and subsequent processes where machinery is used, that our attention is chiefly directed ; and for that purpose I have selected a woollen mill erected for the Turkish Govern- ment at Izmet, on the Gidf of ancient Nicomedia. I might have taken the large establishment of Messrs. B. Gott & Sons, of Leeds, for illustration ; but for the same reason of having all the processes on one floor, as in the previous case of the cotton DESCRIPTION OF WOOLLEN MILLS. 183 factory at Bombay, I have deemed it necessary to do the same in that of wool. There is considerable novelty in the style of the buildings for these works, and the arrangement of the machinery. They were built in 1 843, and contained all the improvements of woollen machinery up to that date. They consist of a quadrangular square with a court. A, fig. 301, in the centre; b, the entrance ; Fig. 301. and the buildings on each side, at a a, contain the offices and rooms for the Sultan, who took great interest in the works, and frequently visited them. The main building, c, was appro- priated to the machinery ; and the side wings, d d, formed the magazines, cloth-rooms and other conveniences, e, the water- wheel, in a separate building, gave motion to the machinery in every part of the works. At the end of the wing-buildings on each side were the steam boilers and retorts for gas, and the de- signs were so arranged as to lock up the whole of the works with one key. The buildings were erected close to the water-fall on the side of a steep bank, and were designed for the purpose of having the whole of the operations on one floor and within sight. It was arched with iron, and lighted from the top on the 184 OX WOOLLEN MILLS. bazaar principle, a system of building prevalent for ages in the East. The exterior walls were substantially built of stone, with a portico and ornamental entrance, b, in front. It was originally intended to have constructed another water-wheel, as at f ; this was not, however, carried into effect. Plate VII. is a longitudinal section of the building, showing the piers for supporting the floor, the water-wheel, the ma- chinery of transmission, the dye-house, the position of the ma- chinery, roof, &c. Plate VIII. is a plan of the woollen mill, showing the arrange- ment of the different lines of shafting and the machinery, the different passages between the machines, the water-wheel, &c. It will be seen from plate VII. that the floor of the woollen mill is supported by piers of brick, and resting upon these are the cast-iron columns 20 feet long and 8 in diameter, for the support of the roof. The boiler for the dye-works, which also serves as an heating apparatus, is 7 feet diameter and 24 feet long, and from it cast-iron piping 6 inches in diameter ascends to the woollen mill above. As the machinery for driving the stocks and gigs is under- neath the floor of the woollen mill, it could not well be shown in plate VIII. I have therefore constructed an enlarged view, fig. 302, which clearly shows the position of the shafting, and the description of machinery they have to drive. Water-wheel and Milhvork. — Near the city of Izmet a river of considerable dimensions cascades from a height of 28 feet into the gulf, and on the banks of this stream, in the im- mediate vicinity of the sea, the mill was erected. The water- wheel is on the suspension principle, and, together with the millwork, was manufactured, and the buildings erected, by Messrs. W. Fairbairn & Sons, Manchester. It is entirely of iron, 30 feet diameter and 13 feet wide, with 72 buckets, 1 foot 6 inches deep, and an opening of 7 inches for the entrance of the water into the bucket. The internal segment, a, fig. 302, 28 feet 2^ inches diameter, 324 cogs, 3:|-inch pitch, and 14 inches wide on the cog, drives the pinion, 6, 5 feet diameter, and gives motion to a strong cross shaft and bevil 'I'l r W -Q m ^ & ^ (— 1 ^ CO w § w rJ-i t^ E-^ ^^■"■■■Sp'- f^ cH ^^ p\f.xe ym TOR. HIS HIGHNESS THE STJiTATsT Erected in 184 3. ^; WU'wtnz FcLwhcblrrL Sc Sons, McuLOutStt SYSTEM OF GEARING. 185 wheel, c, from which the motion is conveyed to the mill by the vertical shaft d, and the shaft /, driving the gig and stock shafts h and g. From this arrangement of the first motion wheels, it will be Fig. 302. ,fe.- d •• ■ ;,'l ! 1 186 ON WOOLLEN MILLS. seen (see also plate VII.), that the motive power comes almost direct upon the heaviest portion of the machinery, such as the stocks and gig machines, and by the vertical shaft, d, and the horizontal and cross shafts above, it is transmitted to the lighter descriptions of machinery in other parts of the mill. The lower portion of the cast-iron vertical shaft is 11 inches diameter; but after giving off the necessary power by bevil wheels to the horizontal shaft for the stocks, gigs and scouring machines, it is reduced to 10 inches, and tapers to 8 inches at the top. The shafts, /, g, h and k, fig. 302, are of cast-iron ; / is 7-|- inches diameter, g 8 inches diameter, h 5^ inches diameter, and the shaft /v 12 inches diameter. The main horizontal shafts, plate VIII., are 4^ inches diameter, and taper to 4 inches at their extreme ends. A plan of the position of the stocks, gigs, and washing and scouring machines, is shown in fig. 302. The processes pursued in a woollen mill are : — 1. Sorting and washing. 2. Teasing and opening. 3. Carding, roving, and spinning. 4. Warping, dressing, and weaving. * By these different stages of manufacture the wool is con- verted into cloth. The after-processes may be described very briefly as follows : — After a somewhat similar preparatory process of carding, roving, and spinning, similar to that de- scribed under the article cotton, it is taken as it comes from the loom, and submitted to careful washing, by running it over reels through a cistern of water. From this it is trans- ferred to the stocks or fulling mill, and is there submitted to the action of the stock by constant pounding with soap and water in covered boxes, till it attains the required consistency of thickness according to the quality or degree of fineness of the cloth. After this process it is again washed with pure water before it passes to the gigs. Here it is subjected to a severe and almost reverse process; the stocks, by a constant rolling of the cloth in the circular box, give -it a thicken- ing or felting character, by the contraction and twisting of the fibres. But the gigs effect a process of separation by teasles (the prickly husk or pod of the plant known by botanists * For farther information respecting the processes, see Appendix A. THE LEWIS MACHINE. 187 as Dipsaciis falloruin) fixed in a frame attached to the circum- ference of a cylinder about 3 feet 9 inches in diameter, run at a velocity sufficient to draw out the fibres, and lay them parallel with the line of the cloth. This it will be observed is the very reverse of the previous process, and by a system of teasle carding, the cloth is now prepared, when dry, ready for the sheering or Lewis frame. The old process of shearing was effected by stretching the cloth in a frame of convenient length, supported by cushions. On the top of the cloth was fixed two large blades or knives worked by power, and, acting as a pair of scissors, clipped off the projecting fibres, and gave what is called a nap or smooth surface to the body of the cloth. This operation has, however, been superseded by the Lewis frame, invented by Mr. Lewis about the beginning of the present century. This machine consists of an iron frame with fixed rollers, over which the cloth is drawn, and in its passage a roller with a series of thin steel blades or spiral cutters revolves at great velocity, and cuts off the outstanding fibres, previously drawn into position in line with the cloth by the gig machine. This is an expeditious as well as an accurate process, and the cloth sheared in this manner presents, when finished, a close, a shining, and a smooth textiu-e. After the shearing the cloth is transferred to the brushing machines, where it undergoes a similar treatment in the dry, as it received from the gig machines in the wet state ; it is then well brushed and finished ready for the market. I have endeavoured in this short description of the different processes to give some idea of the manufacture of woollens, as the whole of the machinery in former times was constructed by the millwright. Now it is in the hands of the machine maker, and, like every other operation of manufacture of modern times, the division of labour, and the organization of separate trades, warrants not only the extended use of machinery for despatch in the manufacture, but greatly increased economy, and much greater perfection in the quality of the cloth produced. It will be noticed that the manufacture of woollen cloths, such as broad cloths, flannels, blankets, &c., is chiefly derived from the short wools. There is, however, a considerable difference between the woollen and the worsted fabrics, consisting chiefly 188 ON WOOLLEN MILLS. in the woollen yarn being very slightly twisted, so as to leave the fibres at liberty for the process of felting, whilst the worsted yarn is made from long wool, hard spun, and made into much stronger thread. The worsted manufacture, and all the mixed fabrics of wool, cotton, flax and silk, are made by a different process to that of woollen cloth. In the former, the wool, mohair or alpaca, is cleaned and washed similar to the shorter wool. It is then combed, formerly by hand combs, with rows of long teeth, but now by machines of different constructions, some of them heated by steam of the circular form, and others with the teeth of the combs in line. In combing, a little sprinkling of oil is necessary, in the proportion of a fiftieth or a sixtieth of the weight of the wool, in order to increase the pliancy and ductility of the filaments, and to straighten them in parallel layers as they are drawn from the teeth of the comb, and formed into a roving or sliver. From the combing machine the slivers go to the drawing and roving ; and from thence to the spinning machines, in every respect similar to the throstles or water- frames used for cotton. In some cases, and for some description of wools, carding is substituted for combing, and the usual subsequent process of drawing, roving, &c., are gone through, as in many other operations where the wool travels from its raw state to that of yarn. In both the woollen and the worsted manufactures the processes are probably more complex than those of most other textile fabrics, and in that of power weaving the difficulties to be encountered have been considerable, owing to the softness of the material and want of twist, or hardness in the yarn forming both weft and warp. From this cause, the power- loom has made slower progress in the woollen manufacture than in that of worsted and all kinds of mixed stuffs, where a stronger yarn and more rigid material has to be dealt with. The woollen and worsted trades, like most other manu- factures, have increased in an accelerated ratio from the com- mencement of the present century up to the present time. We have no reliable returns of the state of the manufacture at the beginning of the present century; but in 1857, according to the factory returns, there were 806 woollen and 445 worsted mills at work, and the total value of the exports of woollen and worsted goods and yarn was 13,645,175^., or about one-fifth of that of cotton. SPEEDS OF SHAFTS AND MACHINES IN WOOLLEN MILLS. 189 6 <^ ■!->■ ^ ^ ^ »^ 03 M ^ o ^ s -^ o ^ a tl ^^ bD t' ,<3 d f^ 2 -2 a '^.2 a, 1 » 3 ^' 1 III ill be g ■5^ '73 - "J t< 5 ^^ -5 ^ 2 => a • 1 a o a K a -■ ^ brS :^ 1^ a .3 •g'.s 1 » .J ig -boM s ^ -a . ^ ^ ^^ ■/! 2 O »J o n^ t; M S o § ^ bc a 1 j^ :^ ^ r^ -a ci "! CO r2r=i g s «'S a B o u ,ri ft| |_^ ^ ^bsobobcoaapcss a g^ a is -bb-bb s ^ ^ s ^^ y^s rt ^ g p tj 33 a c^ 00 O +i O «J =s 'S o 01 a CO a b CO _o .2 ^ - - O a '-S =:;s::;;~" = = *^ ^ .2 ^ - :: :; = = = :; = 'p 'o ^ t' ? p o o P< !-< ^ as o 00 «p O C^l C'l c? CO Oqib«S-*'^00'^(McqoOO>-l IM 0 lO O CO «D ^ O O O CO i-(0 CO Ai Ah ■ 00 00 O lO o >o o f a Ph 5 CO a «3-TikOt~.COr-(C<3C^^^(M(M (M rt .-1 0'Ci-l(M>0 0> CO OS C5 CTS OS >o Cj O O OS Gi Ci lO > ^ 0) ^ •e t- t^ CD 03 ■* CO (M IM O ■*'•* O a £ X X X X X X X X X X X X 5 ^•-i|(M "1^ H'M ''^l-t ^bl col^ H'M -I-J-I--I01 t^ —1 CO (M iQ >0 CO 5 .= (M00C005OOO00C0O00Tt< 05 -* «5 O O O i-l CO ■* ^•COC5«3COO'1 CO ^r^a^ Xri2 aia a? ^ JS ,S JS " "'^JS.^H-S^rS ■g 2^ '^ Oj 1> '^ Q> a>a-*iCOQO -"^-^OOOOOO-^CXJOOOS^ i-H r-l I-H (M - MIX "TTT ■"!-*; ^^C^ .OC-CO-* tMCOCO o t< s tH J5 t3 S " "^ r.^ o g J ? S be O 'co ^ JH OJ O OJ CO o ■-I (M 1— I Or-I05000«DOCOOOOOOOOOCOOOOC>OOOC<«CO c c = IO«500->* s h. rt Q Q J._lrt._l,_(^^Oi-lf-l^i-0505C5aiC5C5 3 0O0OOOO00OCX)-*-*^-*'^->*i^Tti-#Tl<-!t<»J *"* -t?) -*> ^ .S(MJ.C5t^030005l-»0500C3OO u S ■— 1 I-( ,-1 ^ tS'-H'-H^OOOOOOOOOOOOOOOOOOOO u fi J -♦M-*JJ-i-l< -+M-4N-H' -+*'-*N -If-tS r^H. OJ = >OO«S^OOOiO00O(MOOC0iOOOCC-, '^ &. >. ^ X3 s flH £ "3 3 Pi Z o Cq00=OlMSd. per lb. . . 5,000,000 Shoddy and mungo — . ' r.^r. r.r.r. f 30,000,000 Ibs. shoddv at 2k7. per lb. -» 40,000,000 1 j5^0,,;,Q() „ mungo at 43/ „ j <^09'370 Cotton and cotton warps, -^-^ of the wool 206,537 200,903,666 10,533,399 (2) Dye wares, and soap 1,500,000 (3) Wages — 150,000 work people at 12s. 6(7. per week 4,875,000 (4) Rent, wear and tear of machinery, repairs, coal, interest on capital, and profit — 20 per cent. on the above 3,381,680 Total . . £20,290,079 268 APPENDIX II. II. The visitors were then conducted througli the extensive new and old mills and workshops, where some 3,000 hands were busily engaged in melting, bending, hammering, and twisting great masses of seething iron into every conceivable form its stubborn nature could be made to take. It was really a wonderful sight. On every side, amid thick smoke and deafening clamour, the blazing rites of Moloch — the furnace god of old — were being celebrated. Great furnaces blaring in the fierce white glare which shone from their crevices were stuffed to the mouth with monstrous cranks and shafts and uncouth bosses of red- hot metal. Every noAV and then some one of them was opened, with a flash that filled the smoky atmosphere with a glare as from snow, and a mass of metal, seething and spluttering in a blaze of sparks, was dragged off and moulded, like so much wax, under the blows of steam hammers that made the earth tremble and the whole building to jump and chatter under the stroke, as if from the shock of a little earthquake. It was wonderful to see the skill with which the groups of workmen, uniting all their individual exertions in a series of violent efforts like a weird species of dance, contrived to hedge and move about the great masses on the anvils, so that the hammer struck only where and how they chose. While the heat lasted in the mass, and that was for a long time, they never paused or slackened in their work, and though literally almost scorched by their proximity to red heaps, they kept on toiling till the work was done, and the lump that a quarter of an hour before was almost melted iron was picked up by some huge crane that came travelling along the smoky walls, and carried off, glowing through the gloom, a finished piece of work. At other places there were tilt and lever hammers, wearying the very air with the clattering din of their tremendous strokes. At others great ingots of steel were cast by the Bessemer process — small plates were rolled and roughly cast aside in great red slabs to cool, or hurried backwards and forwards in iron trucks, scorching even the hardened workmen out of their tracks as they came burning past. On every side there were furnaces and smoke and red-hot metals, while in out-of-the-way nooks men in steel caps and wire vizors, and cased below in rough steel leggings, like jack-boots of iron, fought in a crowd like so many salamanders round some rough mass that was dangerous in its fierce heat, and which sent back aggres- sive spurts of red-hot metal in return for every blow. Such fiery combats as these were going on in all directions ; the ' Sheffield carpet' APPENDIX II, 269 of the factory — iron plates — was hot and painful to the feet ; the air "was arid with a sulphxuy warmth that was like the glow of an over- heated stove. "Wlien we have said thus much, and added that there were roaring pipes of steam mounting into the air, side by side with great iron trumpet-shaped piles of chimneys, out of which jets of red flame roared and flapped into the smoke above like gigantic flambeaux— that lower down long lines of lathe bands flew noiselessly in all directions, and that the background was filled in with glimpses of ponderous fly-wheels whirling their arms through the smoke and turning rolling-mills or lapping-hammers, or shearing down with noise- less might the great lumps of iron that were brought in to be cut up, — we have said enough to indicate the view which met visitors on their first introduction to this glowing scene of industry. Though not the first, yet by far the most imj^ortant process which their Lordships were shown, was the operation of rolling the gi-eat plate — by far the largest single plate that has ever yet been rolled in the world. This took place in Avhat are called the New Mills of the Atlas "Works, which were used on Thursday for the first time, and where great ranges of furnaces have been erected, with their mouths opening on the iron ti-amway which leads direct to the double roUers through which the plate passes. One may guess at the solidity required for miUs of this kind when it is stated that some of the rolls used at this mill on Thursday have a first foundation of no less than 60 tons of solid iron, resting on masonry carried far below the earth. The rolls themselves are 32 in. in diameter and 8 ft. wide, and are turned by an engine of 400 horse- power, piitting in motion a fly-wheel large enough, apparently, to make a world rotate if only well balanced on its axis. A powerful screw, applying its force through compoimd levers, allows the distance between the roUers to be adjusted to the fraction of an inch, so that the plate which on its first rolling is forced thi'ough an interval of — for instance, 12 inches apart — is on its next Avound through one of 10, next through one of 8, and so on till the requii-ed thickness has been carefully and equally attained by tremendous compression through every part of the metal. There were a great many visitors to see the rolling of this formidable mass, which was fortunate, as one Avoiild certainly be fi-ightened to witness the terrible process alone. After some delay and quick glimpses made by the most hardened Avorkmen, who, i-ushing up to the door of the fiirnace, got a half- blinded glance into its white interior, it was decided that the mass was ready, for, strange as it may seem, an ai-mour-plate requires more than mere heating, and has to be cooked and watched in its cooking with as much care as if it was an omelette, and the plate that is drawn before it is 270 APPENDIX II. ' done to a tui-n,' generally remains a permanent ornament of tlie unlucky manufacturer's workshop, which no one will have at any price. When at last this eventful moment had arrived, on Thursday the door of the furnace was slowly raised, and a colossal pair of pincers Avith very long handles, fastened to a chain drawn by machinery, was swimg in. For an instant some men rushed forward, and, shielding their faces from the deadly heat that shot from the furnace, adjusted the bite of these forceps on the plate, and then ran back as the chain began to tauten, and the great inmate of the blazing den was slowly dragged forth on to the long iron trucks in front of the door, and there lay in its huge length and thickness a mass of living fire, which none could approach, or scarcely even look at, so fierce was its glow and terrific heat. The chains that should have pulled it forthwith to the rollers were too slack, and then arose shouts and cries and commands, as the men did battle with this mass of fire, coming so near it, in their attempts to gather up the slackened chains, that one literally almost expected to see them fall, scorched and shrivelled, on the ground. In its gi-eat glare they fought and struggled with the chains till at last all was adjusted, and the great pile of angiy fire began to move slowly downwards towards the mills, the men following it with hoarse shouts and directions, now hid in steam, as buckets of water were dashed over the mass, and the next moment standing in an atmosphere of white light, to which the light of the day around was mere dusk. The rollers did not bite directly the mass came to them, and when they did the engine was almost brought to a standstill by the tremendous strain upon it ; but at last the soft plate yielded, and the rollers seemed to swallow it as they wound it slowly in, squeezing out jets of melted iron like squirts of fire, that shot about dangerously as the pile was com- pressed from 19 inches to 17 inches thick by the irresistible force of the rollers. Ce n'est que le jJremier jkis qui coute, and the victory AA'as certain when the mass had once passed through the mill, and both visitors and workmen gave a tremendous cheer at the success. From this time it Vv^as kept rolling backwards and forwards, the workmen sweeping from its face the scales of oxide that gathered fast upon it with long-handled besoms that, though soaked in water, caught fire and blazed iip as fast as they were used. With every time it was passed through the rollers were screwed closer and closer together, as we have already mentioned, till at the end of about a quarter of an hour, after leaving the fiu'nace an almost melted mass, it was passed through for the last time, and came out opposite the furnace door it had so lately left, no longer shooting forth spiteful sparks, but shorn of half its heat, subdued and moulded to its proper form — a finished armoiu'-plate, APPENDIX II. weighing 20 tons, 19 ft. long, nearly 4 ft. wide, and exactly 12 in. tliick throughout fi-om end to end. This is the most signal triumph that any rolling mills have yet achieved. Other smaller plates were then rolled with a quickness and cer- tainty that proved the skill already gained in this new and most important branch of manufacture. One plate was 17 feet long by 4 feet broad and 6^ inches thick ; one 19 feet long by 4i feet wide and 4^ inches thick; -one Ave have already alluded to 41 feet long by 3 feet 10 inches broad and 4^ inches thick. A lesser plate was also rolled 18 feet long, 5 feet wide, with a thickness of 6 inches on one edge and 3 inches on the other. The method of converting cast iron by the Bessemer pro- cess into the tough soft Bessemer metal, a combination of the qualities between soft steel and tough ■wrought iron, was next shoAvn. It is needless now to enter on a description of the very beautifiil and very terrible process, to witness, Avhich the metal goes through in the con- verter as it is stimulated to a white heat by the passage of the air blown by force-piunps upwards through the mass. No fireworks can surpass the brilliancy of the display this process afibrds as it ap- proaches its completion, and the stream of violet flame and clouds of burning sparks pour fi'om the mouth of the converter as fi-om a gigantic squib. Nor is it necessary here to enter into a detail of the noAV well-known process, which was a subject of such contro- versy a fcAV years since, but Avhich is now being so generally and advantageously adopted throughout England and the continent. Suf- fice it to say, that in twenty minutes fi-om the time of putting in the charge of cast iron, it Avas, without any expenditure of labour, poured out into the mould, an ingot of soft tough steel weighing three tons. This metal, after undergoing hammering, is now most extensively used for steel rails at stations, points, and jimctions, Avhere the wear is gi'eat, and in these trying situations it seems almost indestructible. A great deal has also been used in making Blakely rifled guns in this country for both Federals and Confederates. These are the ordnance which the Americans always speak of as Parrott guns, and by them they are more highly prized than those of either Armstrong or Whitworth. Yet it is stated that the Ordnance Select Committee have refiised even to try these guns at Shoeburyness. After these processes were over, and the various planing and filing shops had been dtily examined, the visitors were entertained by Mr. Brown at a most sumptuous dejeuner. INDEX. A GATHARCHIDES, his descrip- ii- tion of the grinding-stones used in the mines on the Red Sea. i. 2 Alaric and his barharic hosts, their obliteration of almost all the me- chanical arts, i. 5 Annular wheels, i. 44. Archimedean screw creeper, i. 62 Architecture, mill. See Mill Archi- tecture Armour plates, machinery for rolling, ii. 260 Axis, main, of a water-wheel, i. 113 — modes of attaching the wheel to the axis, i. 11 7 BAMBOO paper, ii. 230 Bann reservoirs, or Lough Island Reavy, in the county of Down, i. 68, 76, 79 Batenian, Mr., his observations on rainfall, i. 71, et seq. Beam, the great, and the crank, i. 19 Beam engines, stationary, i. 229 Beaming cotton, ii. 179 Bessemer process, ii. 271 Bevel wheels and bevel gear, i. 46 ; ii. 7, 36 — skew bevel wheels, ii. 39 — bevel wheels preferable to universal joint, ii. 108 Blackwell, Mr., his experiments on the discharge of water from weirs, i. 98 Bobbins, silk, ii. 209 Boilers, i. 253 — old forms, i. 253 — Cornish boiler, i. 256 — double-flued stationary boiler, i. 256 — dimensions of boiler at Saltaire, i.258 VOL. II. BUT Boilers — continued. — patented forms, i. 258 — computation of the power of boilers, i. 259 — horses power of boilers, i. 260 — area of heating surface, i. 261 — boiler capacity, i. 262 — area of grate-bar surfaces, i. 263 — evaporative power of boilers, i. 264 — strength of boilers, i. 266 — accessories of boilers, i. 270 — the feed pump, i. 270 — • back pressure valves, i. 270 — feed-water heating apparatus, i. 270 — -water gauges, i. 271 — steam gauges, i. 271 — safety valves, i. 272 — man holes, i. 272 — mud cocks, i. 272 — fusible plugs, i. 272 — plans for the prevention of smoke, i. 273 Bolting machine of a corn mill, ii. 165 Bolton, early cotton manufacture of, i. 8 Bombay waterworks, area drained for, and storage capacity of the reservoir of the, i. 82 Borrowdale, enormous rainfall of, i. 70, 72 Bramah's hydraulic press used for ex- pressing oil, ii. 225 Brindley's machinery for the manu- facture of tooth and pinion wheels, ii. 5 note Buff-jerkins worn by the labouring people of England, till the Common- wealth, i. 6 Butterley, or Whistlemouth, boiler, i. 255 274 CAM OAMBS, i. 52 — to produce a changing reci- procating motion by a combination of the camb and screw, i. 64 ■ — to find the curve forming the groove of a camb, so that the velocity ratio of the rod and axis of the camb may be constant, i. 53. Carron, Smeaton's weir at, i. 86 Catrine works, in Ayrshire, i. 88 — statistics of the, i. 89 . — the Catrine high-breast wheels, i. 126 — statistics of, i. 127 Cattle-mills for grinding corn, i. 2 Charcoal, manufacture of, for gun- powder, ii. 244 China, cotton manufacture of, i. 7 — nankeens, i. 7 — mode of making paper in, ii. 230- 232 Clutches, ii. 88, 90 — Mr. Bodmer's, ii. 91 Concentric wheels, i. 45 Conduits, i. 88 — of the Catrine works, in Ayrshire, i. 88 — friction of fluids from conduits, i. 102 Connectors, wrapping. See Wrapping Connectors Constantinople, description of a corn mill at, ii. 118 Corbet Lough, embankments at, i. 77 Corn mills, early history of, i. 1 ; ii. 117 hand-mills, i. 2 cattle-mills, i. 2 water-mills, i. 4 description of the corn mills erected at Constantinople and at Taganrog, ii. 118, 127 on iron buildings for corn mills, ii. 120 merits of bevel and spur gear for corn mills, ii. 123 — — mechanism by which the grain is treated, both previously and sub- sequently to the process of grinding, ii. 124 list of the various wheels, pi- nions, and pulleys employed in the mill at Constantinople, and the velo- cities imparted to them, ii. 125 INDEX. COT Corn mills — continued. — conical mills of Mr. Schiele and of Mr. Westrup, ii. 128, 129, note — list of wheels and speeds in the corn mill of Taganrog, ii. 130 — floating corn mill and bakery constructed by Messrs. William Fairbairn & Sons, ii. 132 — details of machinery, ii. 139 — the elevator, ii. 139 — the creeper, i. 62, andii. 140 — the separator, ii. 141 — the screening machine, ii. 142 — the smut machine, ii. 145, 146 — the framing, ii. 147 — the driving gear, ii. 149 — the stone case and feeding hopper, ii. 149 — the mill-spindle and its appendages, ii. 150 — the millstones, ii. 152 — adjustment of the lower stone, ii. 154 — adjustment of the mill- spindle, ii. 155 — the feeding apparatus, ii. 157 — the disengaging apparatus, ii. 159 — the stone-lifting apparatus, ii. 161 — the dressing machine, ii. 163 — the bolting machines, ii. 165 — Clarke & Dunham's contrivance for balancing the running millstone, ii. 169 Cornish boiler, i. 256 Cottage cotton manufacture of Eng- land, i. 8 Cotton cloth, history of the manufac- ture of, i. 5, 7 — origin of the cotton manufacture in India, i. 7 — cotton manufacture of China, i. 7 — and of Italy, i. 7 — rise of the cotton manufacture of England, i. 7 — cottage cotton manufacture, i. 8 — improvements of Arkw right, Har- greaves, and Crompton, i, 8 — See also Cotton mills Cotton mills, early history of, ii. 1 1 3, 1 7 1 — condition of the factory system thirty years ago, ii. 172 — description of a modern mill as constructed by Messrs. William Fairbairn & Sons, ii. 173 INDEX. 275 COT Cotton mills — continued. — mode of working, ii. 173 — cotton mill engines, ii, 173 — the opening machines, ii. 174 — the blowers, ii. 174 — carding, ii. 174 — drawing frames, ii. 175 — slabbing or roving frame, ii. 175 — machine for combing instead of carding, ii. 176 — process of spinning and weaving cotton, ii. 177 — subsequent processes, ii. 178 — twill and figure weaving, ii. 180 — ■ value of the cotton manufacture, ii. 180 — list of the most approved speeds o? the different cotton machines, ii. 180 — list of wheels and speeds, ii. 181 Cotton paper, ii. 233 Couplings for shafts, and engaging and disengaging gear, ii, 79, etseq. Crank and great beam, the, i. 19 — relations of crank and piston, i. 21 Creepers of corn mills, ii. 140 Crown wheels, i. 46 Crushing rollers for oil mills, ii. 222 Cumberland, rainfoll of, i. 70, 72 Cutting machine of Messrs. Peter Fairbairn & Co., of Leeds, ii. 10 D ALTON, Dr., his observations on rainfall, i. 73. Dams or weirs, i. 83 Deanston works, details of the, i. 130 Detent, ratchet-wheel and, i. 29 Dimities, early English manufacture of, i. 8 Discharge of water, and the estimation of water power, i. 91 Domestics, manufacture of, ii. 203 Drawing flax, ii. 199 Dressing cotton, ii. 179 Dressing machine of a corn mill,ii. 163 Dutch take the lead in the field of mechanical enterprise, i. 5 Dyer's Croft, remains of a Roman water mill at, i. 4 I^CCENTRIC wheel, the, i. 52 J Edward IIL, improvements in the the manufacture of woollen goods introduced by, 1. 6 Egyptians, the ancient, their know- ledge of the processes of spinning and weaving, i. 6 Elevators of corn mills, ii. 139 England, cotton manufacture of, i. 7 — its preeminence in productive in- dustry, i, 8 Epicycloidal teeth of wheels, ii. 17 Estimation of water power, i. 109 Evaporation and rainfall, i. 69 T^ACE-wheel and lantern, i. 45 J- Face-wheels and trundles, ii. 7 Factory system, rise of the, in Eng- land, i. 8 — division of labour by means of the, i. 9 — Dr. Ure's definition of the word ' factory,' i, 9 — effects of the factory system, i. 10 Fairbairn, Messrs. Peter & Co., of Leeds, their cutting machine, ii. 10 Feed pumps of boilers, i. 270 Feed-water heating apparatus of boilers, i. 270 Feeding apparatus of a corn mill, ii. 157 Feeding hopper of a corn mill, ii. 149 Felting of wool, known probably before spinning and weaving, i. 6 — modern process of, ii. 182 Flax mills, history of, ii. 190 — Mr. J. G. Marshall's account of the flax manufacture, ii. 190, 191 — flax manufacture of Ireland and Scotland, ii. 190 — Dr. Ure's description of flax, ii. 191 — account of a flax mill erected for the Baron Stieglitz at Narva, ii. 192 — processes of flax manufacture, ii. 196 — lists of wheels and speeds, ii. 204 — and of pulleys and speed of ma- chines, ii. 205 Flishmann's tow-combing machine, ii. 201 Framing of a corn mill, ii. 147 Friction of shafting, ii. 74 Friction clutch, ii. 85 Friction cones, ii. 86 Friction coupling, ii. 87 Friction discs, IL 87 T 2 276 INDEX. Friction, means adopted to lessen the, at the foot of the main vertical shaft, ii. 105 Fulling cloth, art of, attributed to Nicias of Megara, i. 6 — blankets and broadcloth, ii. 182, 186 Fustians, early English manufacture of, i. 8 GRATE-BAR surfaces of boilers, area of, i. 263 Guide pulleys, i. 34 Gun cotton, invention of, ii. 2.52 Gunpowder mills. See Powder mills Gutta percha, value of, for straps, ii. 3 TTAMMERS, iron, ii. 255 8-i- Hangers, ii. 93 Heberden,Dr., his observation on rain- falls, i. 71 Heckling flax, ii. 197 Herbert, Mr., his oil mill, ii. 221 Hero of Alexandria, his mention of toothed wheels, ii. 4 High-pressure engines, i. 245 Hydraulic presses adapted to express- ing oil from seeds, ii. 225 IDLE wheels, i. 44 India, invention of cotton cloth in, i. 7 Intermittent motion produced by link- work connected with a ratchet- wheel, i. 29 Involute teeth of wheels, ii. 26 Ircn manufactures, changes in pro- gress in the, i. 10 — improvements in the smelting pro- cesses effected by Mr. Neilson, i. 10 — mills, ii. 253 — processes of manufacture at present employed, ii. 253 — hammers and squeezers, ii. 255 — rolling mills, ii. 257 — ' uses,' ii. 257 — machinery for rolling armour plates, ii. 260 — description of the process of roll- ing armour plates at Messrs. John Brown & Co.'s works at Sheffield, ii. 268 Italy, cotton manufactures of, i. 7 Izmet, description of the woollen mill at, built for the Sultan, ii. 182 TAMES I., his abortive efforts to '-' grow the mulberry and produce silk in England, i. 5 Journals, length of, ii. 73 T ANTERN, face-wheel and, i. 45 -L* Lewis's frame for shearing wool- len cloth, ii. 187 Linen, manufacture of, i. 5 ; ii. 196 Linen hand-loom weavers of Ulster, ii. 203 Link- work, i. 18 — the crank and great beam, i. 19 — to construct Watts's parallel mo- tion, i. 23 — to multiply oscillations by means of link-work, i. 25 — to produce a velocity which shall be rapidly retarded by means of link-work, i. 26. — to produce a reciprocating inter- mittent motion by means of link- work, i. 27 — ratchet-wheel and detent, i. 29 — intermittent motion produced by link-work connected with a ratchet- wheel, i. 29 Lombe, Mr. John, his silk mill, ii. 206 Longendale Valley, rainfall of, i. 74 Losh, Mr., his double furnaces, i. 274 Lough Island Reavy. See Bann Reser- voirs. Lubrication of shafting, ii. 77 1 " ACHINERY of transmission, on, iH ii.i Man holes of boilers, i. 272 Manchester, Roman water mill at, i. 4 — early cotton manufacture of, i. 7 McNaughting, i. 239 Mechanical arts obliterated by the conquest of Rome, i. 4 Mechanism, principles of, i. 12 — general views relative to machines — definitions and preliminary expla- nations, i. 12 MEC Mechanism — continued, — parts of a machine, i. 15 — elementary forms of mechanism, i. 17 — link- work, i. 18 — the crank and great beam, i. 19 — to construct Watt's parallel mo- tion, i. 23 — to multiply oscillations by means of link-'work, i. 25 — to produce a velocity which shall be rapidly retarded by means of link-work, i. 2G — to produce a reciprocating inter- mittent motion by means of link- work, i. 27 — ratchet-wheel and detent, i. 29 — intermittent motion produced by link-work connected with a ratchet- wheel, i. 29 — wrapping connectors, i. 30 — endless cord or belt, i. 30 — speed pulleys, i. 32 — guide pulleys, i. 34 — to prevent wrapping connectors from slipping, i. 35 — systems of pulleys, i. 36 — to produce a varying velocity ratio by means of wrapping connectors, i. 38 — on wheel-work jiroducing motion by rolling contact when the axes of motion are parallel, i. 40 — idle wheels, i. 44 — annular wheels, i. 44 — concentric wheels, i. 45 — wheel-work when the axes are not parallel to each other, i. 45 — face-wheel and lantern, i. 45 — crown wheels, i. 46 — to construct bevel wheels and bevel gear, when the axes are in the same plane, i. 46 — to construct bevel gear when the axes are not in the same plane, i. 47 — variable motions produced by wheel-work having rolling contact, i. 48 — Roemer's wheels, i. 49 — intermittent and reciprocating mo- tions, produced by wheel-work having rolling contact, i. 49 ■ — the rack and pinion, i. 50 — sliding pieces, producing motion by sliding contact, i. 51 INDEX. 277 MIL Mechanism — continued. — the wedge, or movable inclined plane, i. 51 — the eccentric wheel, i. 52 — cambs, wipers, and tappets, i. 52 — the swash plate, i. 55 — screws, ditfcrent forms oi,\.5&,etseq. — mechanism for cutting screws, i. 63 — to produce a changing reciprocating motion by a combination of the camb and screw, i. 64 — • to produce a boring motion by a combination of the screw and toothed wheels, i. 65 — on prime movers, i. 66 — accumulation of water as a source of motive power, i. 66 — on the flow and discharge of water, and the estimation of water power, i. 91 — on the construction of water- wheels, i. Ill — on the undershot water-wheel, i. 148 — on turbines, i. 154 — varieties of stationary steam- engines, i. 228 — boilers, i. 253 — windmills, i. 276 Medlock river, Roman water-mill on the, i. 4 Melbourne waterworks, statistics of the, i. 82 — table of rainfall and evaporation, i. 83 Mill architecture, on, ii. 110 — early history, ii. 110 — Smeaton and Rennie's improve- ments, ii. Ill — the Albion steam-mills, ii. Ill — early cotton mills, ii. 113 — the shed principle or ' saw-tooth ' system, ii. 115 — corn mills, ii. 117 — cotton mills, ii. 171 — woollen mills, ii. 182 — flax mills, ii. 190 — silk mills, ii. 206 — oil mills, ii. 221 — paper mills, ii. 230 — powder mills, ii. 243 — iron mills, ii. 253 Mill-spindle, and its appendages, the, of a corn mill, ii. 150 278 MIL Millstones, li. 152 — adjustment of the lower stone, ii. 154 — stone-lifting apparatus, ii. 161 — Clarke and Dunham's contrivance for balancing the running millstone, ii. 169 Millwrights, and engineers, and ma- chinists, ii. 219 — claims of the millwright upon almost every mechanical profession, ii. 219 Mud cocks of boilers, i, 272 NANKEEN manufacture, the Chi-, nese, i. 7 Narva, Baron Stieglitz's flax mill at, ii. 192 Neilson, Mr., his improvements in the smelting of iron, i. 10 ODONTOGRAPH, Prof. Willis's, ii. 31 Oil mills, ii. 221 — early history, ii. 221 — Mr. Herbert's mill, ii. 221 • — modern processes for obtaining the oil, ii 222, et seq. — • comparative merits of stampers and hydraulic presses, ii. 228, 229 — extent of English oil manufacture, ii. 229 Oscillations, to multiply, by means of link-work, i. 25 PAPER MILLS, ii. 230 — early history of the manufac- ture of paper, ii. 230 — Chinese mode of making paper, ii. 230-232 — English paper manufacture, ii. 232 — variety of the materials used in the manufacture of paper, ii. 233 — various stages of the manufacture of paper, ii. 235 — improved paper mills, ii. 236 — section, plan, and cross section of a mill, ii. 237-239 — water marks, ii. 240 — different kinds of paper, ii. 241 — papier-mache, ii. 241 INDEX. RAI Paper mills — continued. — extent of the paper manufacture, ii. 241 — list of wheels and speeds, ii. 242 Parallel motion, Watt's, to construct, i. 23 Phillips, Mr., his observations on rain- fall, i. 72 Pinion from Ramelli, ii. 5 Pipes, friction of fluids in, i. 102 — tables of friction, i. 106, 107 Piston, relations of the crank and, i. 21 Pliny, his description of Roman corn mills, i. 2 Plugs, fusible, i. 272 Plummer-blocks, ii. 93 Pompeii, cattle corn mills disentombed in, i. 2 Poncelet, M., his undershot water- wheel, i. 151 Powder mills, ii. 243 — expansive force of gunpowder, ii, 243 — other expansive substances, ii. 243 — process of manufacture of gun- powder, ii. 244 — description of the government pow- der mill at Waltham Abbey, ii. 246 — construction of mixing mill, ii. 248 — composition of gunpowder among various nations, ii. 251 — list of wheels and speeds, ii. 252 Press, the common, i. 59 — the hydraulic, ii. 226 Pressure of water, i, 91 Prideaux, Mr., his improvements iu boilers, i. 275 Prime movers, i. 66 Pulleys, speed, i. 32 — guide, i. 34 — systems of pulleys, i. 36 — on pulleys and wheels, ii. 1 nUERNS, Roman, i. 2 T)ACK and pinion, the, i. 50 -L^ Rags, advantages of, over all other materials used for making paper, ii. 234, 235 Rainfall and evaporation, i. 69 — table of mean rainfall at London and Manchester, i. 69 INDEX. 279 nAi Rainfall — con tin ued. — method of determining the rainfall, i. 70 — rain-gauges, i. 71 — increased rainfall corresponding to increased elevation, i. 72 — relation of rainfall to the discbarge by rivers, i. 74 — Lough Island Reavy, or river Bann reservoirs, i. 68, 76 — rainfall and evaporation in tropical countries, i. 82 Ramelli, pinion from, ii. 5 Ratchet-wheel and detent, the, i. 29 — intemiittent motion produced by link- work connected with a ratchet- wheel, i. 29 Reciprocating intermittent motion, to produce a, hy means of link-work, i. 27 Reeling flax, process of, ii. 202 Regnault's apparatus for determining the latent heat of steam, i. 221 Rennie, Mr. John, his introduction of cast-iron into all the details of mill- work, ii. 7 — his improvements in mill architec- ture, ii. Ill Reservoirs, formation of, i. 67 — large works of this kind, i. 68 Rolling contact, motion produced by, i. 40 — variable motions produced by wheel- work having rolling contact, i. 48 Rolling mills used in iron manufac- ture, ii. 257 Romans, their querns, or hand-mills, i. 2 — their water-mills, i. 4 — woollen manufactures of the, i. 6 Roving flax, process of, ii. 200 n AFETY valves of boilers, i. 272 kJ Sails of windmills, forms and pro- portions of the, i. 278 Saltaire mills, the, ii. 102, 115 — stationary beam engines at, i. 229 — dimensions of boiler at, i. 250 Sang, Mr., his arrangement for the approximate measurement of the flow of water over a rectangular notch in a waste board, i. 101 Screen, or shaker, for oil mills, ii. 222 Screening machine of a corn mill, ii. 142 Screws, i. 56 — construction of a helix, or screw, i. 56 — transmi.ssion of motion by the screw, i. 57 — pitch of a screw, i. 57 — solid screw and nut, i. 58 — the common press, i. 59 — compound screw, i. 60 — endless screw, i. 61 — diiferential screw, i. 61 — Archimedean screw creeper, i. 62 — mechanism for cutting screws, i. 63 — to produce a changing reciprocat- ing motion by a combination of the camb and screw, i. 64 — to ])roduce a boring motion by a combination of the screw and toothed wheels, i. 65 Scutching flax, ii. 196 Separators of corn mills, ii. 141 Shafts, on the strength and proportion .of, ii. 50 — 1. The ilaterial of which shafting is constructed, ii. 51 — 2. Transverse Strain, ii. 52 — rules for the strength of shafts, ii. 54 — resistance to flexure — weights pro- ducing a deflection of ^ Lg of the length in cast-iron cylindrical shafts, ii. 58 — resistance to flexure — weights pro- ducing a deflection of ^^'gg of the length in wrought-iron cylindrical shafts, ii. 59 — deflection arising from the weight of the shaft in both cast-iron and wrought-iron cylindrical shafts, ii.60 — 3. Torsion, ii. 61 — values of modulus of torsion ac- cording to Mr. Bevan, ii. 63 — resume of experiments on cylinders of circular section, ii. 64 — resume of experiments on the torsion of hollow cylinders of cop- per, ii. 65 — resume of experiments on the torsion of elliptical bars, ii. 65 — safe working torsion for cast-iron and for wrought-iron shafts, ii. 68,69 280 ^^ SHA Shafts — continued. — diameter of -wrought-iron shafting necessary to transmit -with safety various amounts offeree, ii. 71 — 4. Velocity of Shafts, ii. 72 — 5. Length of Journals, ii. 73 — 6. Friction, ii. 74 — table of coefficients of friction under pressures increased continu- ally up to limits of abrasion, ii. 76 — 7. Lubrication, ii. 77 — 8. On Couplings for shafts, and engaging and disengaging gear, ii. 79, et seq. — disengaging and re-engaging gear, ii. 82 — 9. Hangers, plummer-blocks, &c., for carrying shafting, ii. 93 — diameters, pitch, velocity, &c., of spur fly-wheels of the new construc- tion, ii. 101 — Material, &c., of the main shafts, ii. 101 — vertical shafts, ii. 102 — the Saltaire mills, ii. 102, ef seq. — table of length, diameter, &c., of couplings, coupling-boxes, &c., ii. 109 Shaws' waterworks at Greenock, i. 68 Shrouds of a water-wheel, i. 1 18 Shuttle-box, revolving, of the power- loom, ii. 180 Silk, efforts of James I. to grow the mulberry, and produce silk in Eng- land, i. 5 — progress of the silk manufacture in this country during the reigns of Charles I., the Commonwealth, and Charles II., i. 6 — foundation of the Spitalfields weav- ing trade, i. 6 Silk mills, ii. 206 — early history of silk, ii. 206 — the first silk mill, ii. 206 ■ — improvements in machinery, ii. 207 — Mr. Vernon Royle's mill, ii.207 - — Fairbaira and Lillie's improved silk-spinning mill, ii. 208 — process of manufacture, ii. 209 — speedof shafts, wheels, &c., ii. 212 — raw silk spinning machinery, ii. 213 — novel machines lately introduced into the silk trade, ii. 217 DEX. STE Skew bevel wheels, ii. 39 Sliding-pieces, producing motion by sliding contact, i. 51 — the wedge, or movable inclined plane, i. !)\ — the eccentric wheel, i. 52 — cambs, wipers, and tappets, i. 52 — the swash plate, i. 55 — screws, i. 56 — the common press, i. 59 — to produce a changing reciprocat- ing motion by a combination of the camb and screw, i. 64 Smeaton, Mr., his weir at Carron, i. 86 — his introduction of cast-iron gear- ing in place of wood, ii. 6 — his improvements in mill architec- ture, ii. Ill Smoke, plans for the prevention of from boilers, i. 273 — Watts's patent, i. 273 — Losh's double furnaces, i. 274 — Mr. "Wye Williams and Mr. Pri- deaux's improvements, i. 275 Speed pulleys, i. 32 Spindles, silk, ii. 209 Spinning cotton, process of, ii. 177 — flax, pi'ocess of, ii. 202 — raw silk, machinery for, ii. 213 Spitalfields weavers, establishment of the colony of, i. 6 Spreading flax, ii. 198 Spur gearing, ii. 5 Squeezers, iron, ii. 255 Stamper-press, Dutch, ii 222 Steam, on the properties of, i. 180 — history of the employment of, i. 180 — general laws of vaporisation of, i. 183 — the vaporisation of water, and the formation of steam, i. 186 — the relation between the pressure and temperature of saturated steam, i. 186 — relation of temperature and density of saturated steam, i, 203 — on the latent heat of steam at dif- ferent pressures, i. 218 — on the law of expansion of super- heated steam, i. 224 Steam engines, varieties of stationary, i. 228 — stationary beam engines, i. 229 INDEX STE Steam engines — continued. — compound engines, i. 242 — high-pressure engines, i. 245 — the duty of engines, i. 249 — boilers, i. 253 — plans for the prevention of smoke, i. 273 Steam gauges of boilers, i. 271 Stf am kettle for oil mills, ii. 223 Steam power, expenses of, contrasted ■with those of water power, i. 89 Stieglitz, Baron, his flax mill at Narva, ii. 192 Stone case of a corn mill, ii. 149 Straps compared with geared wheel- work, ii. 2 — materials of which straps are made, ii. 3 — strength of straps, ii. 3 — table of the least width of straps for transmitting various amounts of work over different pulleys, ii. 4 Straw paper, ii. 234 Sulphur, preparation of, for making gunpowder, ii. 244 Swash plate, the, i. 55 Swineshaw Valley, rainfall in the,i. 74 ''FABLE of mean rainfall at London -L and Manchester, i. 69 — showing the amount of spontaneous evaporation and rainfall for twelve months, ending Jan. 31, 1858, i. 83 Tables relating to the Flow and Dis- charge of Water. Table L Theoretical velocity of efflu- ent water, i. 92 — n. Coefficients of discharge of vertical rectangular orifices, thin- lipped, with complete contraction. The heads of water measured at a point of the reservoir where the liquid was perfectly stagnant, i. 95 — III. Coefficients of discharge of vertical, thin-lipped, rectangular ori- fices, with complete contraction. The heads of water measured immedi- ately over the orifice, i. 96 — IV. Theoretical and actual discharge from a thin-lipped orifice of a sec- tional area of one square foot, i. 96 — V. Coefficient of discharge for weirs, from experiments on notches 281 TAB eight inches broad, by Poncelet and Lesbros.i. 98 Table VI. CocflScients of discharge from weirs, from experiments by Mr. Blackwcll, i. 99 — VII. Examples of estimation of dis- charge from weirs, i. 100 — VIII. Discharge of water over a thin- edged notch or weir for every foot in breadth of the stream in cubic feet per second, i. 101 — IX. Friction of water in pipes, i. 106 Tables relating to Water-wheels. Table of diameters of the main axis journals of water-wheels, i. 116 — Proportions of water-wheels, i. 144 Tables relating to the Properties of Steam, Table I. Influence of changes of at- mospheric pressure on the boiling point of water, and the boiling point at different altitudes, i. 184 — II. Elastic force of the vapour of water, i. 1S9 — III. Elastic force of steam, from the experiments of the Frankliu Insti- tute, i. 191 — IV. Results of MM. Arago and Dulong's experiments on the rela- tion of pressure and temperature of saturated steam, i. 192 — V. On the pressure and correspond- ing temperature of saturated steam, i. 202 — VI. Results of experiments on the density of steam at pressures of from 15 to 70 pounds per square inch, i. 212 — VII. The results of experiments on the density of steam at pressures below that of the atmosphere, i. 213 — VIII. On the relation of pressure, volume, and weight of saturated steam deduced from experimental data, i. 215 — IX. The latent and total heat of steam from one pound to one hundred and fifty pounds per square inch, i. 223 — X. Showing the coefficient of ex- pansion of superheated steam, i. 227 Table showing the progressive eco- nomy of high pressure steam, i. 250 w 282 INDEX. TAB Tables relating to straps. See Wrap- ping connectors: — ■ ■ — wheels. See Wheel-work shafts. See Shafts Taganrog, description of a corn mill at, ii. 127 Tail-race, direction of, i. 124 Tappets, or wipers, i. 54 Teeth of wheels. See Wheel-work Textile fabrics, history of mills for the manufacture of, i. 5 ■ silk manufactures in England, i. 5, 6 woollen mills, ancient and mo- dern, i. 6 cotton mills and cotton, history of, i. 7 Thrutchers, i. 238 Toothed wheels, history of, ii. 4 Torricellian vacuum, i. 210 Tow-combing machine, Flishmann's, ii. 201 Turbines, on, i. 154 — turbines in which the water passes vertically through the wheel, i. 155 — turbines in which the water flows horizontally and outwards, i. 159 — turbines in which the water flows horizontally inwards; vortex wheels, i. 163 • — efBciency of turbines, i. 1 73 — water-pressure engines, 174 TTNIVERSAL joint, bevel wheels ^ preferable to, ii. 108 lire. Dr., his description of flax, ii. 191 of the silk worm, ii. 206 — — of materials employed in the manufacture of paper, i. 233 of the manufacture of the ingredients of gunpowder, ii. 244 YALVES, back pressure, of boilers, i. 270 -- safety, of boilers, i. 272 — adapted for the discharge of reser- voirs at great depths, i. 80 Vaporisation, general laws of, i. 183. See Steam Velocity, to produce a, which shall be rapidly retarded, by means of link- work, i. 26 Velocity of water, i. 91, 92 Venice, exportations of cotton cloth three hundred years ago from, i. 7 Ventilation of water-wheels, i. 133 — low-breasted ventilated wheel, i. 135 Vermilions, early English manufac- ture of, i. 8 Vitruvius, his account of water-mills, i. 4 Vortex wheels, i. 163 — experiments on Mr, Thomson's vortex wheel at Ballysillan, to de- termine its efficiency, i. 281 ment gunpowder mills at, ii. 246 Water, on the accumulation of, as a source of motive power, i. 66 — classification of mill machinery, i. 66 — formation of reservoirs, i. 67 — rainfall and evaporation, i. 69 — method of determining the rainfall, i. 70 — Lough Island Reavy, or Bann river reservoirs, i. 76 — amount-of rainfall and evaporation in tropical climates, i. 82 — weirs or dams, i. 83 — conduits, i. 88 — statistics of the Catrine works, i. 89 — water power and steam power, ex- penses of, contrasted, i. 89 — on the flow and discharge of water, and the estimation of water power, i. 91 — relations between pressure, velo- city, and discharge of water, i. 91 — thick-lipped orifices or mouth- pieces, i. 93 — thin-lipped orifices, i. 94 — discharge with incomplete contrac- tion, i. 97 — discharge from rectangular notches, waste-boards, and weirs, i. 97 — Mr. Blackwell's experiments, i. 98 — friction of fluids in conduits and pipes, i. 102 — flow of water in open channels, i. 105 — estimation of water power, i. 109 Water gauges of boilers, i. 271 Water marks on paper, ii. 240 Wafer-mills for grinding corn, history of, i. 4 INDEX WAT Water- wheels, on the construction of, i. 1 1 1 — classification of ■svater-machiues, i. Ill — vertical water-wheel, improvements in, i. 112 — component parts of water-wheels, i. 113 — the overshot water-wheel, i. 121 — the pitch-back wheel, i. 124 — direction of tail-race, i. 124 — the Catrine high-breast wheels, i. 126 — of the Deanston works, i, 130 — ventilation of water-wheels, i. 133 — low-breast ventilated wheel, i. 135 — high-breast ventilated wheel, i. 137 — arrangement of gearing, i. 137 — speed of water-wheels, i. 138 — area of opening of bucket, i. 138 — the shuttle, i. 140 — the water-wheel governor, i. 140 — table of proportions of water- wheels, i. 144 — considerations in designing water- wheels, i. 146 — on the undershot water-wheel, i. 148 — oldformsof undershot wheels, i. 148 — improved forms, i. 149 — Poncelet wheel, i. 151 — turbines, i. 154 — water-wheel of the woollen mill at Izmet, ii. 184 — water-wheelof the Narva mill, ii.l93 Waterworks, Shaws', at Greenock, i. 68 Watt's parallel motion, to construct, i. 23 — his patent for the prevention of smoke, i. 273 Weaving, history of the process of, i. 6 Weaving trade of Spitalfields, esta- blishment of the, i. 6 Wedge, the, or movable inclined plane, i. 51 Weirs or dams, i. 83 — Mr. Blackwell's experiments on the discharge of water from weirs, i. 98 — table of coefficients of discharge from weirs, i. 99 — table of examples of estimation of discharge from weirs, i. 100 — table of discharge over a thin- edged notch, or weir, for every foot in breadth of the stream in cubic feet per second, i. 101 283 WHE We i rs — con tinued. — Mr. Sang's mode of measurement, i. 101 Wheel-work producing motion by rolling contact when the axes of mo- tion are parallel, i. 40 — idle wheels, i. 44 — annular wheels, i. 44 — concentric wheels, i. 45 — when the axes are not parallel to each other, i. 45 — face-wheel and lantern, i. 45 — crown wheels, i. 46 — to construct bevel wheels, or bevel gear, when the axes are in the same plane, i. 46 — to construct bevel gear when the axes are not in the same plane, i. 47 — variable motions produced by wheel- work having rolling contact, i. 48 — Roemer's wheels, i. 49 — intermittent and reciprocating mo- tions, produced by wheel-work hav- ing rolling contact, i. 49 — the rack and pinion, i. 50 — to produce a boring motion by a combination of the screw and toothed wheels, i. 65 — experiments on Mr. Thomson's vortex wheel at Bally sillan, to deter- mine its etficiency, i. 281 — power of straps compared with that of geared wheel- work, ii. 2 — history of toothed wheels, ii. 4 — Hero of Alexandria, ii. 4 — Ramelli, ii. 5 — introduction of cast-iron gearing, ii. 6 — face-wheels and trundles, ii. 7 — bevel wheels, ii. 7, 36 — causes of the defects of wheel- work, ii. 8 — cutting machine of Messrs. Peter Fairbairn & Co., of Leeds, ii. 10 — definitions of spur gearing, ii. 11 — the pitch of wheels, ii. 13 — table of the relation of diameter, pitch, and number of teeth, for wheels of from ^ inch to 5 inches pitch, and from 12 to 200 teeth, ii. 18, 19 — the principles which determine the proper form of the teeth of wheels, ii. 17 284 WHE Wheel-work — continued. — epicycloidal teeth, ii. 17 — construction of epicycloidal teeth, ii. 22 — the rack, ii. 25 — involute teeth, ii. 26 — Prof. Willis's method of striking the teeth of wheels, ii. 28 — Prof. Willis, his odontograph, ii. 30 — general form and proportion of toothed wheels, ii. 32 — table giving the proportions of the teeth of wheels in inches and thirty- seconds of an inch, ii. 35 — table of proportions of teeth of wheels for average practice, ii. 34 — skew bevel wheels, ii. 39 — worm and wheel, ii. 40 — strength of the teeth of wheels, ii. 4 1 — table of thickness, breadth and pitch of teeth of wheels, ii. 43 — table of the relation of horses power transm itted , and velocity at the pitch circle, to pressure on teeth, ii. 4 7 — table showing the pitch and thick- ness of teeth to transmit a given number of horses power at different velocities, ii. 48 — table showing the breadth of teeth required to transmit different amounts of force at a uniform pressure of 400 lbs. per inch, ii. 49 — water-wheel at the woullen mill at Izmet, ii. 184 Wheels and pulleys, on, ii. I Whistlemouth, or Eutterley, boiler, i. 256 Williams, Mr. Wye, his improvements in boilers, i. 275 Willis, Professor, his method of strik- ing the teeth of wheels, ii. 28 — his odontograph, ii. 30 Winding and warping cotton, ii. 179 Windmills, causes of their limited use, i. 276 — the vertical windmill, i. 277 — forms and proportions of sails, i. 278 — regulation of the speed of wind- mills, i. 279 INDEX. WRA Wipers, or tappets, i. 54 Wood paper, ii. 234 Woolf 's engine, i. 242 Woollen cloth, history of the manu- facture of, i. 5, 6 — woollen manufactures of the Ro- mans, i. 6 — and of the English in the reign of Edward III., i. 6 — difference between woollen and worsted fabrics, ii. 188 — Mr. Edward Baines's paper on the woollen manufacture of Leeds quoted, ii. 263 Woollen mills, ii. 182 till lately always driven by water-power, i. 7 effects of the introduction of improved machinery, i. 7 — the felting process, ii. 182 — — description of the woollen mill erected for the Sultan at Izmet, ii. 182, et seq. water-wheel and millwork, ii. 184 — — processes pursued in a woollen mill, ii. 186 — — lists of wheels and speeds, and of pulleys and speeds of machines, ii. 189 Worm and wheel, the, ii. 40 Worsted manufacture, value of the, ii. 188 Wrapping connectors, i. 30 ; ii. 1 — — endless cord or belt, i, 30 speed pulleys, i. 32 guide pulleys, i. 34 to prevent wrapping connectors from slipping, i. 35 systems of pulleys, i. 36 to produce a varying velocity ratio by means of wrapping con- nectors, i. 38 power of straps compared with that of geared wheel-work, ii. 2 table of the approximate width of leather straps in inches neces- sary to transmit any number of horses power, ii. 4 I'HTNTED BY SPOTIISWOOUE AND CO., NEW-STREET SQUAUE, tOXDO:f ^ TJ Fairoairn, oir wiliiain lOyo Ireati^^e nn mills • ■'^'^ -^"llwor' University of California SOUTHERN REGIONAL LIBRARY FACILITY Return this material to the library ^rom which it was borrowed. ?§ 1 9 1988 OCT 7 li " UCLA/SEL INTERLIBRARY LOANp [VI. AR 011996 OUE TWO WEEKS FROM DATE OF REdEiPT NON-REi'icWAbLE RECEIVED MAY 1 1996 ;el/ems library .>m fcg?nf— • A 000 316 664 2 Wiv M72 p 1 Hiii: