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LEATHER MANUFACTURE 
 
 A PRACTICAL HANDBOOK 
 
 TANNING, CURRYING, AND CHROME 
 LEATHER DRESSING 
 
 By ALEXANDER WATT 
 
 AUTHOR OF "THE ART OF SOAP-MAKING," " ELECTRO-METALLURGY," ETC., ETC. 
 
 FIFTH EDITION, THOROUGHLY REVISED AND ENLARGED 
 
 NEW YOEK 
 
 D. VAN NOSTRAND COMPANY 
 
 23 MURRAY AND 27 WARREN STREETS 
 LONDON 
 
 CROSBY LOCKWOOD AND SON 
 
 1906 
 
s/#¥3 
 
 Jo 
 
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PEEFACE. 
 
 The Author deems it advisable, in explanation of the 
 appearance of the present volume, to mention that, not- 
 withstanding diligent inquiry, he was unsuccessful in 
 meeting with an English work on the subjects com- 
 prised therein. It is true there are articles upon Leather 
 Manufacture in our various scientific cyclopgedias and 
 technical journals, but to the Author's mind it appeared 
 strange that so important an art should be unrepre- 
 sented by a special work upon the subject in this 
 country, while other countries, especially Trance, Ger- 
 many, and Austria, have provided numerous books upon 
 the various branches of the trade. 
 
 It therefore seemed to the Author that a carefully pre- 
 pared Handbook, embodying all the information he could 
 gather which seemed likely to be useful to the various 
 trades concerned, and including recent processes and im- 
 provements, could not fail to prove widely acceptable to 
 manufacturers and others interested in the art. He con- 
 sequently set to work to construct such a book, with the 
 result which is now in the reader's hands. 
 
 In referring to the numerous sources of information 
 
iv PREFACE. 
 
 upon the subject, the Author was much surprised at the 
 vast store of useful knowledge which was Avidely diffused 
 through a considerable number of works and periodicals 
 not directly addressed to the trade, much of which would 
 probably never come within view of those for whom it 
 was written. To these, and the several trade journals — 
 The Leather Trades' Circular, The Tanners? and Curriers* 
 Journal, and The Scottish Leather Trader — he gratefully 
 acknowledges his indebtedness ; as also to the several 
 works referred to throughout the volume. 
 
 Soon after having determined to undertake the present 
 work, the Author put himself in communication with 
 several manufacturers, requesting permission to have a 
 general view of their works, and to those who kindly 
 acceded to his request he now returns his warmest thanks, 
 but more especially to Messrs. Bevingtons & Sons, the 
 eminent tanners of Bermondsey, and to Messrs. Carlaw 
 Brothers, for the generous spirit in which they ex- 
 plained to him the various processes of manufacture 
 conducted at their establishments. He has also to thank 
 Mr. Sparke Evans, of the Avonside Tannery, Bristol, for 
 many useful suggestions. 
 
 In conclusion, the Author indulges a hope that his effort 
 to supply an evident want in English technical litera- 
 ture, may meet with the approval of his readers, and that 
 the book will prove useful for reference to everyone con- 
 nected with the art. 
 
PUBLISHEES' NOTE TO THE 
 FIFTH EDITION. 
 
 Since the issue (in 1897) of the Fourth edition of this 
 work, as revised by the late Mr. Alexander Watt, rapid 
 strides have been made in the Leather industry. In fact, 
 so great and constant, it appears, are the advances now 
 being made, that it is all but impossible to keep abreast 
 of them in a technical Handbook. The Publishers felt 
 assured, however, that much of the data here collated 
 and prepared by Mr. Watt was far too valuable to be 
 cast aside, and having, after that gentleman's death, 
 received inquiries from all parts of the world as to when 
 a revised edition would be available, they felt themselves 
 fortunate to be able to engage the services of a well- 
 known expert who was prepared (within the limits 
 arranged) to thoroughly revise the work, and make 
 such additions as should bring it up to date. This was 
 by no means an easy task, but it is believed that the 
 Keviser (while retaining such parts of Mr. Watt's work 
 as were of permanent value) has succeeded in giving, 
 also in a condensed and easily digestible form, a sum- 
 mary of most of the modern methods now pursued 
 by Tanners and Leather Manufacturers. Several of the 
 
VI PUBLISHERS' NOTE TO THE FIFTH EDITION. 
 
 original chapters, dealing with older-fashioned leathers 
 which have practically passed out of use, have been 
 omitted, their place being taken by descriptions of 
 tanning and dressing the more modern leathers, such 
 as chrome, calf, and goat skins. In some cases, the 
 space available would not allow him to do more than 
 give the bare technical outlines of the processes in- 
 volved ; and in others the Reviser has had to assume a 
 certain amount of knowledge on the part of the reader. 
 
 A brief description has been added of the " Standard " 
 method of tannin estimation, but the scientific reader 
 who requires fuller information on this important sub- 
 ject is referred to Prof. H. E. Procter's " Leather Indus- 
 tries Laboratory Book," where he will find full justice 
 done to the Chemistry of Leather Manufacture. The 
 illustrations of machinery (it will be found) have been 
 brought up to date, but it will not be forgotten that 
 so rapid is the progress made by the Tanner's Engineer 
 that new ideas for appliances are of almost daily occur- 
 rence. The introduction of the Chrome process of leather 
 manufacture was a golden opportunity for mechanical 
 enterprise, of which British, American, and Continental 
 engineers have not been slow to avail themselves, and 
 they are reaping a rich harvest in catering for the wants 
 of the Tanner. 
 
 It is right to mention that the technical methods 
 described in the work are such as have stood the test 
 of practical experience, and although some of them may 
 have to be modified to suit individual special or local 
 requirements, yet it is certain that students of the sub- 
 ject will obtain much that is of real value from an 
 intelligent perusal of what is here written. The recipes 
 
PUBLISHERS' NOTE TO THE FIFTH EDITION, vit 
 
 given are not only actual working ibrmiike, but many 
 of them have been hitherto regarded as trade secrets. 
 
 In conclusion, the Publishers may be allowed to 
 quote the words of the Reviser, who has reminded them 
 that " in the Manufacture of Leather competition is 
 becoming keener year by year, and the cost of manual 
 labour is making it almost prohibitive for many pur- 
 poses. ' The old order changeth, giving place to the new,' 
 but it is not without a pang of regret that even the most 
 enterprising man sees the old forms of ancient skilled 
 trades swept aside by the march of progress. However, 
 this seems to be one of the inevitable trading conditions 
 of the twentieth century. The day is over when profit 
 could be made easily and quickly in the leather trade, 
 and it is only by close study of economy in the manu- 
 facture, and careful organisation for the disposal of the 
 product, that progress can be made. In pursuing the 
 former of these two courses, close study, both of the 
 science and of the practice of the Leather industry, is 
 essential ; and if what he has written and compiled in 
 preparing the present edition is a help in that direction, 
 the Reviser will feel that in his attempt to bring the work 
 of the late Mr. Watt into line with modern methods 
 he will have accomplished a most useful service for the 
 followers of a most interesting calling." 
 
CONTENTS. 
 
 TACE 
 
 Intkoduction ...1 
 
 CHAPTEE I. 
 
 CHEMICAL THEORY OF THE TANNING FXOCESS. 
 
 Properties of Gelatine — Action of Tannic Acid on Gelatine, &c. — 
 
 Seguin's Theory of the Art of Tanning 11 
 
 CHAPTEE II. 
 
 THE SKIN. 
 
 The Skin — Structure of the Skin — Mr. Ashe's Description of the Skin 
 
 — Composition of the Skin 23 
 
 CHAPTEE III. 
 
 HIDES AND SKINS. 
 
 Classification of the Skins of Animals — Condition of Hides and Skins 
 — Hides — Native Hides — Dried Hides — Salted Hides — Dried 
 Salted Hides— Selection of Hides — Warbles — Abusive Treatment 
 of Raw Hides — Kips— Buffalo Hides — norse Hides — Ass and 
 Mule Hides — Hippopotamus Hides — Calves' Skins — Sheep Skins 
 — Lamb Skins — Goat Skins — Kid Skins — Hog and Pig Skins — 
 Seal Skins — Deer Skins — Porpoise Skins — Serpent and Croco- 
 dile Skins 28 
 
X CONTENTS. 
 
 CHAPTER IV. 
 
 TANNIN OR TANNIC ACID. 
 
 TAGB 
 
 Tannin or Tannic Acid — Preparation of Tannic Acid — Pelouze's Pro- 
 cess — Berzelius' Process — Bouillon-Legranee's Process — Merat- 
 Guillot's Process — Dize"s Process — Deyeux's Process — Proust's 
 Process — Serturner's Process — Schering's Process — Badvil and 
 Lienders' Process — MM. Coez's Process — Kohlrausck's Process 
 — Properties of Tannic Acid — Parnell's Views — Pure Tannic 
 Acid — EeactioDs of Tannic Acid — Table of the Percentage of 
 Tannin in Vegetable Substances — Morfit's Observations — 
 Artificial Tannin ......... 43 
 
 CHAPTER V. 
 
 GALLIC ACID. 
 
 Gallic Acid — Preparation of Gallic Acid from Galls — Scheele's 
 Method — Liebig's Method — Graham's Method — Pharmaceutical 
 Methods — Properties of Gallic Acid — Pyrogallic Acid — Ellagic 
 Acid 57 
 
 CHAPTER VI. 
 
 GALLIC FERMENTATION. 
 Checking or Preventing Gallic Fermentation . . . .63 
 
 CHAPTER VII. 
 
 TANNING MATERIALS. 
 
 Sources of Tannin — Barks — Oak Bark — Barking of Trees — Nut 
 Galls — Tanning Extracts — Catechu — Kino — Gambier or Terra 
 Japonica — Hemlock Extract — Chestnut Extract — Oakwood Ex- 
 tract — Larch Extract — Quebracho Extract — Sumac — Bhatany 
 Boot — Mmigrove Extract — Myrobalans — Valonia — Divi divi — 
 Mimosa Bark — List of Tanning Materials — Miscellaneous Tan- 
 niDg Materials . . . . . . . .68 
 
CONTENTS. XI 
 
 CH APT ETC VIII. 
 
 ESTIMATION OF TANNIN. 
 
 PAGE 
 
 Examination of Bark — Determination by Specific Gravity — The 
 Barkometer — Chemical Methods of Estimating Tannin — Davy's 
 Method — Bell Stephens' Method — Hammer's Method — Lowen- 
 thal's Method— Mr. Hewitt on Lowenthal's Method — Mr. Procter 
 on Lowenthal's Method — Rainspacker's Method — The Tanno- 
 meter — Casali's Process — -Standard Method — International Asso- 
 ciation of Leather Trades' Chemists . . . . .88 
 
 CHAPTER IX. 
 
 PRELIMINARY OPERATIONS. 
 
 Treatment of Green or Fresh Hides — Method of Salting Hides — 
 Cleansing the Raw Hides — Dried Hides — Softening Dried Hides 
 — Brain's Process — Dry Salted Hides— Wet Salted Hides — 
 Schultz's Views on the Treatment of Hides .... 108 
 
 CHAPTER X. 
 
 DEPILATION OR UN HAIRING SKINS AND HIDES. 
 
 Depilation by Lime — Properties of Lime — Storing the Lime — Liming 
 — Single Pit Method — Working in Rounds — Continental Method 
 of Liming — Supposed Disadvantages of the Lime Process — Dr. 
 Davy on the Action of Lime on Animal Matter — Working on the 
 Beam — Rounding the Pelts — Depilation by Sweating — Cold 
 Sweating — Depilation by Acids — Depilation by Saccharine 
 Matter — Depilation by Caustic Soda— Depilation by Bisulphide 
 of Calcium — Depilation by Charcoal — Depilation by Sulphide 
 of Sodium— Palmer's Process — Beck's Process — The Pullman- 
 Payne Process ......... 115 
 
 CHAPTER XI. 
 
 RAISING OR SWELLING. 
 
 Raising— Bating— The Bate, or Grainer— The Pure— Scudding— 
 Sulphuric Acid Bate — Turnbull's Process — Warrington's Process 
 — Bating with Barley-meal— Lactic Acid for Bating — Formic 
 Acid for Bating 138 
 
Xli CONTENTS. 
 
 CHAPTER XII 
 
 TANNING BUTTS FOR SOLE LEATHER. 
 
 PAGE 
 
 Bark Tanning — Old Methods of Tanning — -Modern System of Tanning 
 — Preparation of ihe Ooze — The Leaches — The Handlers— The 
 Layers — Mixed Tannages — Tanning by Suspension — The Sus- 
 penders — Scouring — Drying the Tanned Butts — Old American 
 Method — The Drying Loft — American Turret Drier — Working 
 of the Turret Drier — Influence of Light upon Leather — Striking 
 — Rolling the Leather — To determine when Leather is Tanned 
 throughout .......... 143 
 
 CHAPTER XIII. 
 
 TANNING PROCESSES. 
 
 The First English Patents for Tanning— Newton's Tanning Process 
 — Aldricu's Process — Orgereau's Process — Jennings's Process — ■ 
 Ballatschano and Trenk's Process — Lomas's Process — Michel, 
 Kollen, and Hertzog's Process — Keasley's Process . . .109 
 
 CHAPTER XIV. 
 
 TANNING PROCESSES— (continued). 
 
 Page's Process — Casimir Bez and Sons' Process — Snyder's Process — 
 De Bock's Process — Funcke's Process — Hamer's Process — Cox's 
 Process — Nossiter's Process — Desmond's Process — Burbidge's 
 Process — Kleman's Process ....... 191 
 
 CHAPTER XV. 
 
 TANNING EY PRESSURE. 
 
 Spilsbury's Process — Drake's Process — Knowly's and Ducsbury's 
 Process — Fryer, Watt, and Holmes's Process — Mouren's Process 206 
 
 CHAPTER XVI. 
 
 QUICK TANNING. 
 
 Quick Tanning — Dr. Ure's Views — Dussauce's Observations — Dietz'e 
 Process — Needham's Process — Nuessly's Process — Bell's Process 
 — Baron's Process — Another Quick Process — Guiot's Process — 
 Danish Quick Process . . . . . . . .211 
 
CONTENTS. Xlll 
 
 CHAPTER XVII. 
 
 HARNESS LEATHER TANNING. 
 
 PAGE 
 
 Harness and Upper Leather — Crop Leather ..... 223 
 CHAPTER XVIII. 
 
 AMERICAN TANNING. 
 
 Cold Sweating of Hides — Sweat Pits — Treatment of Hides in the 
 Sw^at Pits — Treatment of Hides after Sweating — Liming — Un- 
 hairing by Prof. Lupkin's Process — Beam Work — Trimming or 
 Rounding — Grinding the Bark — Leaching — The " Press " Leach 
 — Raising with Vitriol — Handling — The Rocker Handler — The 
 Layers 228 
 
 CHAPTER XIX. 
 
 HEMLOCK TANNING. 
 
 Pratt's System of Tanning — Hemlock Tanning of New Lebanon — 
 
 Hibberd's Process 245 
 
 CHAPTER XX. 
 
 TANNING EY ELECTRICITY. 
 
 Ward's Process — Gaulard's Process — Gaulard's Second Process — 
 Merit en's Process — Crosse's Process ..... 254 
 
 CHAPTER XXI. 
 
 CHEMICAL TANNING. 
 
 Knapp's Processes— Heinzerling's Chrome Process — Heinzerling's 
 
 Second Chrome Process — Vanderstraaten's Process . . . 260 
 
 CHAPTER XXII. 
 
 MISCELLANEOUS PROCESSES. 
 
 Indian Method of Prepariug Elk-skins — Old Irish Process of Tanning 
 — Tanning Nets, Sails, and Cordage — Glycerine in Tanning — 
 Bleaching Leather . 268 
 
XIV ' CONTENTS. 
 
 CHAPTEE XXIII. 
 
 PAGE 
 
 ON THE COST OF AMERICAN TANNING . . 272 
 
 CHAPTER XXIV. 
 
 MANUFACTURE OF LIGHT LEATHERS. 
 
 Russia Leather — Count Kartstoff's Description of Russia Leather 
 Manufacture — Smoking Skins — Another Method of Preparing 
 Russia Leather — Black Russia Leather — Yufts Russia Leather 
 — Morocco Leather — Sumac Tanning — Imitation Morocco 
 Leather — Skiver — Cordovan Leather — Roan — Hungary Leather 
 — Wallachia Leather — Barley Dressing — Morfit's Remarks on 
 "White Dressing — Red Dressing — Bran Dressing — Enamelled 
 Leather .......... 276 
 
 CHAPTEE XXV. 
 
 DYEING LEATHER. 
 
 Dyeing Morocco Leather — Dyeing with Aniline Colours — Dyeing 
 Kid Leather for Boots — Bath Dyeing — Dyeing on a Flat Surface 
 — Aniline Colours in Glove Dyeing — DyeiDg with Pure Aniline 
 Colours 299 
 
 CHAPTER XXVI. 
 
 MANUFACTURE OF WHITE LEATHER. 
 
 Tawing as Distinguished from Tanning — TawiDg Operations — Kid 
 Leather : Treatment of Kid Skins — French Kid Leather — 
 Imitation Kid — Continental Method of Preparing Glove Leather 
 — Calf Kid for Uppers — -White Sheep Leather — Splitting Sheep 
 Skins 306 
 
 CHAPTER XXVII. 
 
 CHROME LEATHER MANUFACTURE. 
 
 Preliminary Operations —Liming and Unhairing — Fleshing — Puring 
 or Deliming — Scudding — Chroming Operations — Striking-out 
 and Shaving — Dyeing Chrome Leather — Fat Liquoring — Dye- 
 ing Black — Putting or Striking-out — Oiling and Drying — 
 Staking or Softening —Seasoning — Glazing .... 323 
 
CONTENTS. XV 
 
 CHAPTER XXYIH. 
 
 BOX-CALF MANUFACTURE. 
 
 TAGE 
 
 Striking-out and Shaving— Fat Liquoring— Dyeing Black— Finish- 
 ing Operations . • • • ■ • ■ • • <™-° 
 
 CHAPTER XXIX. 
 
 CHAMOIS, OR OIL-LEATHER MANUFACTURE. 
 Preparation and Frizing— Drenching— Stocking or Milling in Oil- 
 Pressing and Washing— Finishing — Chamois Glove Leather — 
 Bleaching— Tucking— Colouring— Buff Leather— Liming— Pre- 
 paring and Milling— Scudding and Wash-house— Buck Skin 
 Dressing— Milling or Stocking— Scudding and Wash-house . 357 
 
 CHAPTER XXX. 
 
 CURRYING. 
 
 The Scouring-house— The Shop— The Curriers' Knife — Currying 
 Kip Leathers — Waxed Kip Butts — Sorting and Pounding — 
 Soaking and Softening — Re-tanning — Drum-stuffing — Setting — 
 Finishing — Stoning and Starching — Graining — Waxing— Top- 
 sizing — Currying Satin or Glove Shoe Leather — Soaking and 
 Splitting — Buffing— Blacking and Setting — Finishing Satin or 
 Glove Leather— Levant Leather — Soaking and Splitting — 
 Setting, Buffing, and Embossing — Black — Seasoning and Glaz- 
 ing — Oiling — Currying Various Leathers — Wax Calf Skins — 
 Calf Skins for Memel — High Shoes, Black Grain— Split Cow- 
 hides for Brown Bags — Blocking Boot-fronts .... 368 
 
 CHAPTER XXXI. 
 
 MACHINERY EMPLOYED IN LEATHER MANUFACTURE. 
 
 " Stocking " or Softening Machines— Dcpilxtion and Fleshing Plant 
 — Machines for Crushing and Grinding Tanning Materials — Sole 
 Leather Finishing Machinery — Leather Dressing Machinery — 
 Scouring and Setting Machinery — Embossing and Softening 
 Machinery — Tanning and Stuffing Drums — '■ Boarding " and 
 Softening Machines — Machinery used in Chrome Leather 
 Manufacture— Machinery used in the Beam House— Finishing 
 Machinery for Chrome Work ...... 399 
 
XVI CONTENTS. 
 
 ( 
 
 CHAPTER XXXII. 
 
 EMBOSSING LEATHER. 
 
 PAGE 
 
 Copying Crocodile, Alligator, &c, Si ins ..... 431 
 CHAPTER XXXIII. 
 
 FELLMONGERING. 
 Classification of Sheep Skins— Treatment of the Skins . . . 434 
 
 CHAPTER XXXIV. 
 
 PARCHMENT, VELLUM, AND SHAGREEN. 
 
 Preparation of Parchment and Vellum — Skins for Drumheads— Sha- 
 green — Fish Skin, or Fish Shagreen 437 
 
 CHAPTER XXXV. 
 
 GUT-DRESSING. 
 
 Preparation of Cattle Intestines : Continental Method — Goldbeaters' 
 Skin— Lathe Cords — Cords from Sheep Intestines— Cords for 
 Tennis Bats, &c. — Whipcords — Gut Strings for Musical Instru- 
 ments ........... 441 
 
 CHAPTER XXXVI. 
 
 GLUE-BOILING. 
 
 Treatment of Glue-pieces, &c. — French Glue — Parchment Glue- 
 Size— Glue Waste . . . 449 
 
 CHAPTER XXXVII. 
 
 UTILISATION OF TANNERS' WASTE. 
 
 Spent Tan — Guest and Court's Process— Hide and Skin Cuttings — 
 
 Hair Waste — Lime Waste- Glucose in Leather . . . 455 
 
 Index 462 
 
EEEATA IN TEXT. 
 
 Page vi., line 5, for ' chrome, calf ' read ' chrome calf.' 
 ,, xi., ,, 6, for ' Mr. Procter ' read ' Prof. Procter.' 
 ,, xi., ,, 8, for 'Standard Methods — International Association' 
 read ' Standard Method of the International Asso- 
 ciation.' 
 ,, xi., ,, 29 (Chapter Heading), for ' Raising or Swelling ' read 'De- 
 liming or Bating.' 
 ,, xv., ,, 21, for ' Black ' read ' Blacking.' 
 ,, xv., ,, 29, for ' Leather Dressing Machinery' read ' Shaving and 
 
 Splitting Machinery.' 
 ,, 88, ,, 6, for 'Mr. Procter ' read ' Prof. Procter.' 
 ,, 88, ,, 8, for ' Standard Method.— International Association ' 
 read 'Standard Method of the International Asso- 
 ciation.' 
 138-142 (Chapter Heading), for ' Raising or Swelling ' read ' De- 
 liming or Bating.' 
 Page 399, line 6, for ' Leather Dressing Machinery ' read ' Shaving and 
 Splitting Machinery.' 
 
 Watt's ' Leather Manufacture. 
 
THE AET 
 
 OF 
 
 LEATHER MANUFACTURE. 
 
 INTRODUCTION. 
 
 In future ages the past century will ever be famous, 
 not only for its important discoveries and useful inven- 
 tions, but it will also be marked as an era in which, 
 however tardily at first, the teachings of Science were 
 accepted, and many useful arts rescued from empiricism 
 and ignorance. Even within the memory of many now 
 living, the innovations of Science were formerly looked 
 upon with suspicion, as being not only unnecessary but 
 possibly fraught with mischief. What could chemists 
 know about soap-making, or of the art of tanning hides ? 
 If good soap and good leather could be produced for so 
 many generations without the aid of Science, why not 
 continue in the same track as of old ? Reflections such 
 as these inspired the workers in these arts for a long time 
 after they were proved to be based upon definite chemical 
 laws ; and it is well known that a deaf ear was turned to 
 those who ventured to assert, and even to prove, that 
 chemistry was indissolubly allied to those arts which had, 
 from time immemorial, been conducted chiefly by the 
 judgment of uneducated workmen. 
 
 Although it must be confessed that the discovery of the 
 chemical principles involved in the art of tanning has not, 
 in its application, improved the quality of leather, still this 
 important knowledge has enabled the tanner to work 
 with greater economy and certainty, while Chemical 
 Science has furnished him with an abundance of tanning 
 materials of which, without such aid, he would doubt- 
 less have remained in ignorance. Moreover, various 
 
 B 
 
2 LEATHER MANUFACTURE. 
 
 methods of quickening the process of tanning have been 
 introduced which, in their turn, have facilitated the pro- 
 duction of leather to meet the ever-increasing demand for 
 this valuable article of universal, requirement. 
 
 Respecting the early history of tanning, some very 
 interesting facts are given in the Gerber Courier of 
 Vienna, from which we extract the following : — " The 
 oldest method of tanning is red or bark tanning, or that 
 in which, in addition to the wooden and iron scraping and 
 rubbing instrument used in the preparation or improve- 
 ment of the hide or skin, limewater and astringent 
 extracts from oak and other kinds of bark, or from other 
 vegetable substances, are employed. It is called red 
 tanning because the tanning substances always contain 
 more or less colouring matter, which dye the leather 
 through and through of a more or less reddish colour. 
 The ancient Orientals understood the art of preparing not 
 only common leather, but even good and often finely 
 coloured varieties, similar to our Morocco and Cordovan. 
 Persian and Babylonian leather has been celebrated time 
 out of mind. Many centuries back such leather was 
 brought from Asia into Europe — first into Turkey, Prussia, 
 and Hungary, and thence, later, into Germany, Holland, 
 England, France, Spain, &c, and these countries subse- 
 quently learned to manufacture leather themselves. In 
 the first centuries of Christianity, the Turks, Russians, and 
 Hungarians were the most celebrated tanners ; subse- 
 quently England, the Netherlands, and Spain endeavoured 
 to equal them. 
 
 "Among five sorts of leather of foreign origin, Cor- 
 dovan, Morocco, Shagrin, and Russian leather have at all 
 times been specially famous. Cordovan, a soft, small- 
 grained, coloured leather, had already been prepared by 
 the ancient Orientals. Its name is derived from the 
 Spanish city of Cordova, whence it was possibly first 
 introduced into Europe, and where, for a long time after- 
 wards, it was chiefly manufactured. It enjoyed a great 
 reputation in the eleventh century, when the most dis- 
 tinguished persons wore shoes of Cordovan leather. The 
 
INTRODUCTION. 3 
 
 French name for shoemaker, ' cordonnier,' appears also 
 to have been derived from this leather. From the gradual 
 improvement of Cordovan, sprang Morocco, called also 
 Turkish and Spanish leather. This beautifully coloured 
 and brilliant leather has always been most excellently 
 manufactured in Morocco, in European and Asiatic Turkey, 
 in KrimTartary, in the Island of Cyprus, &c, and very 
 well also in Russia, Poland, Hungary, and Spain, but 
 especially in England, France, Holland, and Germany. 
 
 " Shag-rill (in Turkish Sagri, and Persian Sagre) is 
 chiefly celebrated for its hardness and strength, and for 
 the peculiarity of its grain side, which appears as if 
 covered with globular granules. It is also of Eastern 
 origin. The best Shagrin is now made in Persia, Con- 
 stantinople, Algiers, and Tripoli. The production of the 
 small globular granules on the grain side was for a long 
 time kept secret. We were first informed by the cele- 
 brated traveller, Pallas, that they were produced by 
 stamping the hard seeds of the wild orach ( Chenopodium 
 allium) into the hide spread on the ground. The 
 seeds were afterwards knocked out, and the hide scraped 
 on the indented side and soaked in water for two days. 
 The Hungarians were, in ancient times, especially cele- 
 brated for their white tanned leather, which was imitated 
 in France as long ago as three hundred years. 
 
 "We beg our readers to go back some centuries in 
 history, and they will be convinced that the products of 
 our trade were known in the time of Moses ; for at that 
 period leather carpets were already used in tents. These 
 we may still meet with among the Arabs. Coloured 
 leather seems also to have been common, for Ezekiel 
 speaks of fine red leather, which was probably our 
 splendid red Morocco. Leather was also used in the 
 remotest ages by the Israelites as a material to write 
 upon, for they used strips made of leather for this pur- 
 pose. According to the testimony of Herodotus, the 
 ancient Ismians wrote their annals upon sheepskin, and 
 the ancient Persians likewise, according to Diodorus of 
 Sicily. According to Herodotus, the ancient Libyans 
 
4 LEATHER MANUFACTURE. 
 
 wore leather clothing ; the Ichthyophagists on the banks 
 of the Araxes dressed themselves in sealskins; and in 
 the time of Alexander the wild inhabitants of Geodrosia 
 used the hides of animals for clothing, and covered their 
 dwellings with leather. Homer praises the splendid half- 
 boots of Agamemnon, and Hesiod recommends leather 
 shoes lined with fur. For many years leather was used 
 by the Greeks in the construction of ships, especially by 
 the Phoenicians, who originally inhabited an arid, sandy 
 corner of the earth between the Red Sea and the Mediter- 
 ranean, where the soil was not favourable to the growth of 
 timber, and they were obliged to supply its place by 
 covering their boats, constructed of willows woven to- 
 gether, with leather or hides, which, even thus early, 
 were subjected to a certain amount of dressing. The 
 ancient Germans also, who lived on the sea-coast, and 
 the original Britons, equally possessed this custom. 
 
 "It is asserted that the art of dressing leather in 
 general, upon the so-called Hungarian method, was first 
 brought from Senegal, in Africa, and made known to us 
 in the middle of the sixteenth century by Buscher, the 
 son of a tanner in Paris. At that time leather was com- 
 mon in Hungary, and dressed leather was very highly 
 esteemed. In the year 1584 two German tanners, named 
 Lasmagne and Aurand, came to Neufchatel, in Lorraine, 
 where they worked at their trade ; from thence they went 
 to St. Deziers, in Champagne, and finally to Paris, where 
 they prepared very good leather. The theory that the 
 preparation or tanning of the hides was discovered cen- 
 turies ago, and that the leather produced was employed 
 for the same purposes as at present, is further confirmed 
 by the following old proverb, which is proof that leather 
 shoes were already worn at that time : ' We must not 
 steal leather to give away shoes in God's name.' This 
 refers to the legend of St. Crispin, who stole leather to 
 make shoes out of it for the poor. In the old form of 
 speech, ' to draw from the leather ' signified to draw the 
 sword. In low Saxon the same expression signifies to 
 undress." 
 
INTRODUCTION. 5 
 
 Although, the preceding observations indicate that the 
 writer believed that the art of converting skins and hides 
 into leather was not only exceedingly ancient, but also 
 widely diffused, it is equally probable — except among the 
 early Egyptians,* who must have known a comparatively 
 high state of civilisation — that the so-called leather was 
 in reality the skin or hide of the slaughtered animal 
 merely dried in the sun or smoke-cured, and not what we 
 understand by the term leather. Indeed it is well known 
 that untanned skins have from all time been used by un- 
 civilised tribes (as is also the case at the present time) for 
 clothing and many other purposes. In some parts of 
 France, even at the present day, bottles are made from 
 skins of animals sewn up, and are used for the conveyance 
 of wine and oil. The skins of animals were also used for 
 making vessels to contain liquids — even wine ; but it is 
 more than probable that the skins were merely dried in 
 the sun and then externally greased to render them pliant 
 and preserve them from the effects of moisture, or were 
 cured by smoking, and not tanned in the ordinary sense. 
 In support of this view, David, in Psalm cxix. 83, says, 
 " I am become like a bottle in the smoke," which would 
 indicate that the (skin) bottles in his time were cured by 
 smoking. The preservative effects of the volatile matters 
 given off by burnt wood were doubtless known at the 
 earliest periods, and it is therefore reasonable to infer that 
 the Psalmist alluded to this mode of preserving bottles 
 made from the skins of smaller animals. Again, in the 
 preceding verse, David says, "Mine eyes fail for thy 
 word ; " may not this, taken in conjunction with his sub- 
 sequent complaint, indicate that his vision, being impaired, 
 caused him to behold objects as through a mist — " like a 
 bottle in the smoke." Job, in chap. xxx. 30, says, " My 
 skin is black upon me, and my bones are burnt with heat," 
 
 * In the Egyptian collection of the British Museum may he seen a 
 leather workman's apron, with a small purse-shaped pocket at the right 
 side ; leather shoes with round toes, ankle and fore straps, most of them 
 for children ; also other shoes of coarser and stouter make, and sandals of 
 various forms and sizes ; shoes with high peaked toes ; rolls of prepared 
 leather of a maroon colour, a yoke with one leather strap remaining, &c. 
 
6 LEATHER MANUFACTURE. 
 
 probably also comparing bis lamentable condition to that 
 of a bottle being cured by the smoke from burnt wood. 
 Our Saviour refers to tbe necessity of putting new wine 
 into new bottles, "else the new wine doth burst the bottles." 
 Assuming that such bottles were made from the skins of 
 animals, it is obvious that in course of time, through long 
 use, they would become 'perished, as it is termed, and in 
 such a brittle condition as to render them incapable of 
 withstanding the pressure of new wine. 
 
 In ancient writings the words skin and leather are evi- 
 dently synonymous, but probably refer to the dried or 
 cured skin. Kennett, in his Antiquities of Rome, speak- 
 ing of the shoes, slippers, &c, worn by the ancient Romans, 
 eays, "The perones were a kind of high shoes, rudely 
 formed of raw hides, and reaching up to the middle of the 
 
 leg Dacier tells us that the senators had two 
 
 sorts of shoes, one for summer and the other for winter. 
 The winter shoes were made of an entire black skin, or 
 sometimes a white one, reaching up to cover the greater 
 part of the leg, without any open place except at the top. 
 .... It is uncertain whether the calcei mullei (red 
 shoes) were so called from the colour of the mullet, or 
 whether they lent a name to that fish from their reddish 
 dye. They were at first the peculiar wear of the Alban 
 
 kings, afterwards of the kings of Rome Julius 
 
 Caesar, who was very singular in his whole habit, was 
 particularly remarkable for wearing mullei on ordinary 
 
 days The Roman solece were a sort of sandals, 
 
 without any upper leather, so that they covered only the 
 sole of the foot, being fastened above with straps and 
 buckles. These were the ordinary fashion of the women, 
 
 and therefore counted scandalous in the other sex 
 
 The crepicla had two soles, whereas the solece consisted 
 but of one. The former word is supposed to be derived 
 from crepitus, creaking, from the peculiar sound which 
 the double soles produced. Momus, when brought to 
 censure Venus, could find no fault in her except that her 
 slippers creaked a little too much ! " The Romans appear 
 to have acquired a knowledge of leather manufacture at a 
 
INTRODUCTION. 7 
 
 later period, and to have pursued it with great success. It 
 is said that boots and shoes equal to those of the present 
 age were worn by Roman ladies, and Pliny alludes to hides 
 being tanned with bark, and also states that gall nuts, 
 sumach, and lotus bark were employed in tanning. 
 
 About 1300 A.D., embossed leather of great beauty was 
 produced, specimens of which, in the form of tapestry, are 
 still preserved in some of our old English mansions. 
 Spain, Italy, Flanders, and England were famous for the 
 production of embossed leather richly coloured and gilt. 
 This"art having also been practised by the early Egyptians 
 nearly three thousand years ago, it is probable that the 
 countries above named may have revived and improved 
 upon the Egyptian art. 
 
 It was not until the end of the eighteenth century, and 
 the commencement of the nineteenth, that the subject of 
 tanning received the attention of scientific men, and the 
 great result of their investigations was that the 'principles 
 of the process of tanning were fully developed, and the 
 chemical action of the tanning agents upon the pelt, or un- 
 haired skin, definitely determined. The researches of 
 Lewis, Deyeux, Seguin, Macbride, Prevost, and Sir 
 Humphry Davy established the fact that the process of 
 tanning was a chemical art, and as such should be con- 
 ducted with a due amount of scientific method. But many 
 years elapsed — nearly half a century, indeed — before 
 tanners would recognise any suggested improvement. 
 
 Up to about seventy years ago the tanners were men of 
 small means, diffused throughout the country, unaided by 
 railway communication and the advantages of machinery, 
 while being utterly free from any knowledge of chemical 
 principles. As a contrast to this condition of the trade, 
 we have now an accumulation of extensive tanneries, 
 many of which are situated near the great ports where 
 the raw materials are landed from abroad ; and the 
 capital invested in these establishments runs into 
 several millions. In some of these the principles of 
 the art are not only understood but more or less 
 generally followed, while the advantages of labour-saving 
 
8 LEATHER MANUFACTURE. 
 
 machinery have been recognised, and mechanical appli- 
 ances adopted which the tanners of old would have looked 
 at but to condemn. 
 
 As the principles of tanning became better understood, 
 many attempts were made to hasten the tardy conversion 
 of skins into leather, some of which, emanating from 
 practical tanners, being not only ingenious, but possessing 
 the merit of being of a fairly practical nature. The first 
 of these processes was due to Francis Spilsbury, who, in 
 1823, took out a patent for a process by which the tanning 
 liquor was forced through the skins by hydrostatic pres- 
 sure. A modification of this process was introduced by 
 William Drake in 1831, which consisted in having two 
 skins sewn together, forming a watertight bag, in which 
 the tanning liquor was introduced by means of a funnel ; 
 the bag being thus filled, was kept constantly in this con- 
 dition until the tanning was complete. In 1826, Messrs. 
 Knowlys and Duesbury procured a patent for hastening 
 the impregnation of the skins with tanning liquor by sus- 
 pending them in a close vessel, from which the air could 
 be exhausted by means of an air-pump. By this method 
 the skins were said to be so effectually impregnated with 
 tannin that their conversion into leather was greatly 
 accelerated. 
 
 Many other mechanical contrivances have from time to 
 time been introduced, with a view to promote the rapid and 
 uniform absorption of tannin by the skins, amongst which 
 may be mentioned Nossiter's plan of separating the skins, 
 while in the tan liquor, by wooden frames or partitions ; 
 Keasley's arrangement for raising and lowering the skins 
 alternately during the tanning operation, as a substitute 
 for "handling;" and, more recently, Bez and Sons' 
 method of tanning hides by means of a continuous flow or 
 current of tanning liquor. These and other processes will 
 be described in the subsequent pages. 
 
 Since the period when Davy examined the chief tannin- 
 yielding plants known in his time, a vast number of vege- 
 tables have contributed to the tanner's list of tanning 
 materials, some of which, employed either alone or mixed 
 
INTRODUCTION. 9 
 
 with other sources of tannin, have proved highly service- 
 able in the production of leather. Amongst these may be 
 mentioned hemlock, valonia, mimosa, divi divi, myroba- 
 lans, quebracho, &c. The foremost of these — hemlock — 
 is the chief tanning agent of the Northern States of 
 America, in which it abounds in unlimited profusion. 
 Oakwood and chestnut extract is also largely imported 
 into this country from Canada and the Continent. 
 
 Many methods have been devised for the estimation of 
 tannin, but the system proposed by Lowenthal, and sonie- 
 whatTniodified by our own chemists, is now generally ac- 
 cepted as the most reliable. While the simpler methods 
 of determining the percentage of tannin, by the amount of 
 gelatine required for its precipitation, or by the amount of 
 tannin which a given weight of dried skin absorbs, will 
 afford an approximate estimate of the proportion of tannin 
 in a sample of bark or other tannin material, Lowenthal's 
 method is capable of giving far closer and more reliable 
 results than any other at present known.* 
 
 Expatiating on the importance and extent of the leather 
 manufacture in this country, Dr. Campbell says : " If we 
 look abroad, on the instruments of husbandry, on the im- 
 plements used in most mechanical trades, on the structure 
 of a multitude of engines and machines ; or if we contem- 
 plate at home the necessary parts of our clothing — shoes, 
 boots, and gloves — or the furniture of our houses, the 
 books on our shelves, the harness of our horses, and even 
 the substance of our carriages, what do we see but in- 
 stances of human industry exerted upon leather ! What 
 an aptitude has this single material, in a variety of circum- 
 stances, for the relief of our necessities and supplying 
 conveniences in every state and stage of life ! Without 
 it, or even without it in the plenty we have it, to what 
 difficulties should we be exposed ! 
 
 * Since the above was written, the " Standard Method," as adopted 
 by the International Association of Leather Trade Chemists, is now 
 generally used by European chemists for tannin estimation. A con- 
 densed description of this is given at the end of chap. viii. p. 104. — Ed. 
 Fifth Edition. 
 
io INTRODUCTION. 
 
 While, in the early part of the past century, the 
 soaprnaker was constantly under the surveillance of the 
 exciseman, the tanner was equally favoured by the con- 
 stant presence of that official supervisor ; at the soap- 
 works, the coppers were locked and unlocked night and 
 morning by the exciseman, while at the tanyard not a 
 single hide could be shifted without his supervision, and 
 in the case of any breach of the excise laws heavy penalties 
 were inflicted. In the year 1830 the leather tax was 
 abolished, and as evidence of the great impetus which this 
 caused to the trade, in the year 1828 the value of exports 
 of leather and saddlery were, collectively, £183,361, while 
 in 1882 these exports'amounted to £2,348,242. 
 
 Since that date, British trade in leather and leather 
 goods has shown continued expansion. In 1905, leather 
 to the value of £2,112,823 was exported, boots and 
 shoes £1,882,294, and saddlery and harness to the value 
 of £518,082. This, it must be remembered too, has 
 been done in the face of ever-increasing hostile tariffs, 
 for even the Australian Commonwealth has so raised the 
 import duties, that it now only pays to send the finest 
 classes of leather goods to the Antipodes. 
 
CHAPTER I. 
 CHEMICAL THEORY OF THE TANNING PROCESS. 
 
 Properties of Gelatine. — Action of Tannic Acid on Gelatine, &c 
 Seguin's Theory of the Art of Tanning. 
 
 The process of tanning consists in the conversion of the 
 skins of animals into leather, by chemically combining 
 with the substance of the skin an astringent vegetable 
 principle called tannin, or tannic acid; and in order to 
 thoroughly understand why this conversion takes place 
 when skins are immersed in a solution of the tanning 
 principle, we must know something of the chemical com- 
 position of the skin itself. When the cuticle, or scarf 
 skin, has been removed from the cutis, or true skin, it is 
 found that the latter is almost entirely soluble when boiled 
 in water, and the solution, after evaporation and cooling, 
 sets into a jelly — this is gelatine, a substance which 
 readily combines with tannic acid. Gelatine is also 
 obtained in the same way from bones, cartilages, ten- 
 dons, and ligaments. The purest form of gelatine is 
 isinglass, prepared from the air-bladders and sounds of the 
 sturgeon. 
 
 Properties of Gelatine. — Pure gelatine is colourless, 
 without odour, insipid to the taste, and transparent ; it is 
 more or less tough, according to the source from which it 
 is obtained. It is heavier than water, and when heated, 
 it first becomes soft, and then shrinks. When burned, it 
 exhales an odour resembling that of burnt horn. In cold 
 water gelatine softens and swells, but only partially dis- 
 solves; with gentle heat, however, it dissolves freely. 
 Good glue, immersed in cold water, absorbs about three or 
 four times its own weight of that liquid without dissolving. 
 
12 LEATHER MANUFACTURE. 
 
 One part of isinglass dissolved in 100 parts of water, gela- 
 tinises on cooling ; but in 150 parts of water it remains 
 liquid; the gelatinising of the solution, however, will 
 naturally depend upon the temperature of the atmosphere 
 and the quality of the gelatine. The skins and tissues of 
 the older animals yield a firmer jelly than those from 
 younger ones. According to Brande, when a solution of 
 gelatine is repeatedly warmed and cooled, more especially 
 if it be boiled, it gradually loses its tendency to gelatinise, 
 and becomes more and more soluble. In close vessels 
 jelly may be kept in cool weather for some days without 
 change ; but in open vessels it soon becomes mouldy, 
 especially in the vicinity of flowering plants. " Gelatine 
 is not soluble in absolute alcohol, and when alcohol is 
 added to a warm and strong aqueous solution, the gelatine 
 separates in the form of a white viscid substance. It is 
 insoluble in ether, and in fixed and volatile oils. "When 
 common gelatine, glue for instance, is digested in alcohol, 
 it yields a little fat and extractive matter to that solvent. 
 When jelly is immersed in alcohol, it contracts very con- 
 siderably in consequence of the abstraction of water ; it 
 was thus that Gonner applied it for the reduction in size 
 of the impression of lithographic prints ; and, on the other 
 hand, when the original impression was taken upon con- 
 tracted gelatine, it could be so dilated by immersion in 
 water, as to give a greatly enlarged impression of a small 
 print. ' ' — Brande* 
 
 Gelatine is soluble in all dilute acids, in which respect 
 it differs from albumen. When treated with sulphuric 
 acid, leucine and gelatine sugar are formed, the latter sub- 
 stance having been discovered by Braconnot. One part 
 of pulverised glue was mixed with two parts of concentrated 
 sulphuric acid ; after having been left in this condition 
 for twenty-four hours, during which time no discoloration 
 took place, eight parts of water were added, and the mix- 
 ture boiled for five hours, the water being renewed 
 occasionally. The liquor was then further diluted, and 
 saturated with chalk, then filtered and evaporated, when 
 * " Manual of Chemistry." By William Thomas Brande, F.R.S., &c. 
 
CHEMICAL THEORY OF THE TANNING PROCESS. 13 
 
 it yielded a syrup which, at the end of a month, produced 
 small sweet crystals. These were afterwards washed with 
 weak alcohol to separate the adhering syrup, and purified 
 by a second crystallisation. Gelatine sugar requires 414 
 parts of water to dissolve it. 
 
 Action of Tannic Acid on Gelatine, &c. — The most 
 delicate test for the presence of gelatine is tannic acid, 
 and when we consider that a cloudy precipitate is produced 
 by this vegetable acid in a solution consisting of 1 part 
 gelatine in 5,000 parts of water, we may begin to 
 realise its powerful influence upon the skin of animals in 
 the process of tanning. When a piece of prepared skin — 
 that is skin which has been soaked in milk of lime and 
 freed from its cuticle, hair and other extraneous matters 
 — is immersed in a solution of pure tannin (tannic acid) or 
 an infusion of any astringent vegetable containing tannin, 
 such as oak bark or gall nuts, and allowed to remain 
 therein for a moderate length of time, the whole of the 
 tannin combines with the skin, which becomes hardened 
 and insoluble in water, and is absolutely incapable of 
 putrefaction. It is, in fact, leather, and is almost impene- 
 trable to water. 
 
 The characteristic properties of tannin are astringency 
 in taste, and the power of being precipitated from its 
 aqueous solution by a persalt of iron, either of a bluish- 
 black, or a dark green colour. The colour of the pre- 
 cipitate, formed in a solution of tannin by persalts of 
 iron, has been made the basis of an arrangement of the 
 different tannins into two varieties, distinguished as 1, 
 •tannin which precipitates iron bluish-black, and 2, tannin 
 which precipitates iron green. Upon this subject Gfmelin 
 
 " On the validity of the distinction between iron blueing 
 and iron greening tannin, several views have been put for- 
 ward, in which, however, these denominations have been 
 understood as applying to two groups of bodies. If, 
 according to Geiger, water containing a small quantity of 
 alkali be gradually added to a ferric salt [as persulphate 
 of iron], which has been turned green by any kind of iron 
 
14 LEATHER MANUFACTURE. 
 
 greening tannin, the green colour changes to violet-black, 
 the tint usually produced by iron blueing tannin. On 
 adding an acid, the green colour is restored. According 
 to this result, the difference between the two groups might 
 be that the iron blueing tannin is less rich in free acid ; 
 nevertheless, it reddens litmus more strongly than the 
 other kinds of tannin. It appears to contain [_qy. to be 
 capable of yielding] a larger proportion of gallic acid, 
 but iron blueing tannin is not converted into the iron 
 greening kind by the addition of gallic acid (Gmelin). 
 The blue or green reaction is by no means an infallible 
 characteristic of the species of tannic acid, since bases 
 colour the ferric compounds of tannic acid blue, and 
 acids change the blue to green. With ferric acetate, 
 the iron greening acids form a blue compound ; the green 
 compound which they form with other ferric salts is 
 turned blue by the addition of a sufficient quantity of 
 acetate of lead, either neutral or basic, and even by a 
 large quantity of gelatine. A compound of iron greening 
 tannic acid with lead oxide, is turned blue by ferric sul- 
 phate (persulphate of iron) ; an iron greening tannic acid 
 is turned blue by exposure to the air, in contact with iron 
 turnings. But the colours obtained with iron greening 
 tannic acids are very different from those produced by the 
 iron blueing acids, and the two cannot be converted one 
 into the other. 
 
 "Thus, catechu-tannic acid (obtained by exhausting 
 catechu with a small quantity of water), left in contact 
 for a few days with iron filings, assumes a dirty- greyish, 
 not a blue-black colour, and the precipitate does not turn 
 green- when treated with a small quantity of acetic acid, 
 but dissolves on the addition of a larger quantity, and is 
 precipitated a purple-grey on the addition of ammonia. 
 The iron greening tannic acids of catechu, kino, alder, 
 larch, and birch bark, and of tormentilla root, are likewise 
 incapable of yielding a good ink. The extracts of iron 
 greening parts of plants do not yield pyro- gallic acid by 
 dry distillation, unless they contain gallic acid ready 
 formed " (Stenhause). This also shows the incorrectness of 
 
CHEMICAL THEORY OF THE TANNING PROCESS. 15 
 
 the view advanced by Heniing, who regards the two 
 groups as not essentially different from gallo-tannin, and 
 as identical therewith, when pure. 
 
 Dr. Lewis was the first to attempt a chemical analysis 
 of nut-galls, about the middle of the last century, and he 
 detected in them a substance "which coagulates with 
 isinglass, and blackens the salts of iron." Seguin, how- 
 ever, is believed to have been the first to accurately deter- 
 mine the nature of this peculiar action upon gelatine, and 
 also upon the skins of animals, and the term tannin was 
 applied by him to this principle as existing in a variety 
 of vegetable substances employed in the conversion of 
 skins and hides into leather. Proust was the first who 
 attempted to obtain tannin in a pure and separate state, 
 and Sir H. Davy determined its relative quantity in a 
 variety of tanning materials. It was not, however, until 
 1834 that Pelouze discovered a method of separating 
 tannic acid in a pure state (see p. 43). 
 
 Although subsequent researches have to some extent 
 disproved the theory which Seguin promulgated at a time 
 when little was known of the principles of tanning, its 
 reproduction here will not be out of place^.more espe- 
 cially as it will enable us to give the views of other 
 chemists of eminence concerning the weaker points of his 
 theory. 
 
 Seguin 's Theory of the Art of Tanning. — 1. The skin, 
 stripped of its flesh, is a substance which can be easily 
 converted by a convenient process into an animal jelly, 
 which, concentrated and dried in the air, furnishes glue. 
 
 2. A solution of this latter substance being mixed with 
 an infusion of tan, an insoluble precipitate is formed, and 
 this precipitate is not susceptible of putrefaction. 
 
 3. The solution of tan is composed of two distinct sub- 
 stances ; one precipitates the glue, and is the true tanning 
 matter ; the other precipitates the protosulphate of iron, 
 without precipitating the solution of glue, and produces 
 only the disoxygenation of the skin, and of the substance 
 which unites the hair to the skin. 
 
 4. The operation of tanning is not a simple combination 
 
1 6 LEATHER MANUFACTURE. 
 
 of the skin with, the principle which precipitates the glue, 
 but a combination with the skin disoxygenised by the 
 substance which in dissolution in the tan has the property 
 of precipitating the sulphate of iron. Thus all substances 
 to be used to tan ought to have the properties of precipi- 
 tating glue and sulphate of iron. 
 
 5. The operation of tanning consists, first, in the swell- 
 ing of the skins by an acid principle ; second, a disoxyge- 
 nation by gallic acid ; third, in disoxygenating the skin by 
 the same principle ; and by this disoxygenation it is in a 
 middle state between glue and skin ; fourth, in combining 
 it by this disoxygenation. 
 
 That Seguin was in error in supposing that gallic acid 
 entered into the substance of the skin in any considerable 
 proportion, if at all, there cannot be the least doubt. 
 Indeed it has been abundantly proved that such is not the 
 case, and the examination of the exhausted or spent tan 
 liquors detects the presence of this acid in considerable 
 proportion. Dr. Ure says, " In no case is there any reason 
 to believe that the gallic acid of astringent vegetables is 
 absorbed in the process of making leather ; hence Seguin' s 
 theory of the agency of that substance in disoxygenating 
 skin, falls to the ground." Dussauce* gives the following 
 reasons for disagreeing with Seguin's theory : " Whatever 
 are the merits of Segiiin, and the services he has rendered, 
 we cannot but expose all the errors of the above theory. 
 We persist in looking at the swelling of the skin as an 
 effect less chemical than mechanical, which is principally 
 due to the interposition of the water, or to the effect of the 
 caloric produced by fermentation. Acids and alkalies act 
 only as a means of preserving the skin from putrefaction ; 
 afterwards they effect a chemical action. Thus the lime 
 with which the interior of the skin is saturated, notwith- 
 standing all the washings, forms with tannin a tannate of 
 lime, which takes away the suppleness of the leather, and 
 for this reason it is that the lime method is injurious. It 
 
 * " Treatise on the Art of Tanning," &c. Edited from Notes and 
 Documents of Sallerou, Grouvelle, Duval, Dessables, Labarraque, Payen, 
 Rene, De Fontenelle, Malepyre, &c, &c. By Professor H. Dussauce. 
 
CHEMICAL THEORY OF THE TANNING PROCESS. 17 
 
 is not the same with, acids. Besides preserving the skin 
 from putrefaction, the acetic acid produced reacts on the 
 fibrine, softens it, and transforms it partly into a trans- 
 parent jelly, soluble in boiling water, and combining with 
 the tannin. Besides this the acid, by which the skin is 
 more or less saturated, precipitates the solution of tannin, 
 and fixes a larger quantity in the leather. This softening 
 renders the swelling very easy. However, it can be ope- 
 rated without these means, which are in antagonism with 
 Seguin's theory. 
 
 ' ' We do not agree with Seguin that gallic acid is the 
 principal and indispensable agent in tanning. No experi- 
 ment has demonstrated the durable disoxygenation which 
 he asserts, and which is impossible, if we compare the 
 respective constituents of gelatin and fibrin. Thus : — 
 
 Fibrin contains 19-615 per cent, of oxygen. 
 Gelatin ,, 72-207 „ „ 
 
 " From this we see it is impossible that gallic acid dis- 
 oxygenises the fibrine and transforms it into glue, whilst 
 pure gelatin contains nearly one-half more of oxygen. If 
 such were the case, gallic acid must oxidise instead of dis- 
 oxygenising. We therefore see that this theory is inad- 
 missible. Let us now record the experiment : — 
 
 Catechu contains from 48 to 54 per cent, of tannin. 
 Tea „ 34 to 40 „ „ 
 
 Herb Bennet „ 42 „ „ 
 
 Squill „ 24 „ „ 
 
 " These substances, so rich in tannin, are applied with 
 success in tanning ; while, however, they do not contain a 
 particle of gallic acid. Seguin does not mention the ex- 
 tractive ; however, this substance has some action in the 
 tanning, and according to Sir H. Davy its presence is 
 necessary to form a flexible leather, and in some way it 
 may take the place of tannin. In England, where tanning 
 material is very scarce, they have used the decoction of 
 cicuta, and Schwerger has shown by analysis that 100 
 parts of fresh leaves contain 2 '73 of extractive, without 
 
 c 
 
1 8 LEATHER MANUFACTURE. 
 
 tannin or gallic acid. To resume, we regard tanning as, 
 a combination of five principles : fibrin, gelatin, tannin 
 extractive, and acid. 
 
 " 1. Gelatine and fibrin are transformed into a jelly by 
 acetic acid, with tannin, extractive, and gallic acid. 
 
 " 2. In tanning, the epidermis disappears, and no por- 
 tions of the skin have been disoxygenated. 
 
 " 3. The action of gallic acid is similar to that of acetic 
 acid, and its presence is not necessary in the operation. 
 
 "4. Extractive, like tannin, unites with the altered 
 gelatin and fibrin, and renders leather flexible and firm. 
 It is also their colouring principle ; thus leather tanned 
 with gall is pale, that with oak bark brownish, with 
 catechu reddish, &c. It is the extractive which gives the 
 leather a brownish colour, without rendering it insoluble 
 in boiling water. 
 
 " 5. Lime forms with tannin a tannate of lime, which 
 destroys the suppleness of the leather, and renders it dry 
 and brittle. 
 
 " 6. Dried skins, well tanned, increase in weight about 
 33 per cent. This increase is due to the fixation of the 
 tannin, extractive, gallic acid, (?) and a little water. 
 
 "7. In saturated infusions there is less extractive than 
 tannin,* which in weak solutions predominates. That is 
 the reason why it is necessary to place the skins at first 
 in very weak infusions, and lastly to saturate them little 
 by little, with tannic acid and extractive, so as to have a 
 complete tanning and more supple leather. 
 
 " 8. By presenting to strong infusions, the leather con- 
 tains but very little extractive, and is tanned only on two 
 surfaces, the centre containing little, so that the leather 
 obtained is hard and brittle. 
 
 " 9. Lastly, gallic acid exercises so slight influence on 
 tanning that Sir H. Davy thinks that it is doubtful if oak 
 bark contains any." 
 
 The above observations, taken collectively as the opinions 
 of Dussauce, Malepyre, Pay en, Bene, Labarraque, de Fon- 
 tenelle and others, and supporting as they do the views of 
 
 * Davy. 
 
CHEMICAL THEORY OF THE TANNING PROCESS. 19 
 
 that distinguished philosopher, Sir Humphry Davy, cannot 
 fail to prove instructive to those who desire to pursue the 
 art of tanning upon truly scientific principles. While 
 disagreeing with Seguin's views as to the part which gallic 
 acid plays in the process of tanning, we must not forget 
 the great services he rendered to the followers of the tan- 
 ning art by explaining the main principles upon which the 
 art is based, and which, prior to his researches, were but 
 little understood. 
 
 As we have before shown, the process of tanning essen- 
 tially consists in forming a chemical combination of the 
 corium, or true skin of animals, with the vegetable astrin- 
 gent principle tannin. If skins were merely dried — 
 although they would possess a certain degree of hardness 
 and durability while in that state, they would, when sub- 
 jected to moisture, undergo putrefaction, and consequent 
 speedy destruction. Again, untanned skins are pervious 
 to water, and therefore cannot be used for the many pur- 
 poses to which leather is so extensively applied. When 
 skins are tanned, however, not only is their chemical con- 
 stitution changed, but they are also rendered impermeable 
 to water, besides being absolutely unputrefiable. More- 
 over, during the combination of tannin with the skin 
 it is believed that vegetable extractive matter from the 
 bark, &c, also enters somewhat largely into the substance 
 of the skin, to which, no doubt, some of the valuable pro- 
 perties of leather are due. Sir H. Davy observes upon this 
 subject: — 
 
 " When skin is very slowly tanned in weak solutions of 
 the barks, or of catechu, it combines with a considerable 
 proportion of extractive matter ; and in these cases, though 
 the increase of the weight of the skin is comparatively 
 small, yet it is rendered perfectly insoluble in water, 
 forming a soft, but at the same time a strong, leather. 
 The saturated astringent infusions of barks contain much 
 less extractive matter in proportion to their tannin than 
 the weak infusions ; and when the skin is quickly tanned 
 in them common experience shows that it produces leather 
 less durable than the leather slowly formed. Besides, 
 
2 o LEATHER MANUFACTURE. 
 
 in the case of quick tanning, by means of infusions of 
 barks, a quantity of vegetable extractive matter is lost 
 to the manufacturer which might have been made to 
 enter into the composition of the leather." These observa- 
 tions show that there is sufficient foundation for the opinion 
 of the workmen concerning what is technically called the 
 feeding of leather, in the slow method of tanning ; and 
 though the processes of the art may in some cases be pro- 
 tracted for an unnecessary length of time, yet in general 
 they appear to have arrived, in consequence of repeated 
 practical experiment, at a degree of perfection (in the 
 quality of the leather) which cannot be very far exceeded 
 by any elucidations of theory that have yet been made 
 known. 
 
 It must be confessed that the old tanners, although they 
 may be said to have worked upon the rule-of-thumb prin- 
 ciple, often had for their guidance those useful substitutes 
 for scientific knowledge — good common sense and keen 
 observation. Hence we find that they discovered, m prac- 
 tice, that hides tanned slowly produced the best leather, 
 in which view they were supported by Sir Humphry 
 Davy, who found that saturated infusions of astringent 
 barks contained much less extractive matter in propor- 
 tion to their tannin than weak infusions. Davy further 
 observes, " On the first view it appears singular that in 
 those cases where extractive matter forms a certain portion 
 of the leather, the increase of weight is less than when the 
 skin is combined with pure tannin ; but the fact is easily 
 accounted for when we consider that the attraction of skin 
 for tannin must be probably weakened by its union with 
 extractive matter ; and whether we suppose that the tannin 
 and extractive matter enter together in combination with 
 the matter of the skin, or unite with sejDarate portions of 
 it, still, in either case, the primary attraction of tannin for 
 the skin must be to a certain extent diminished." 
 
 " In examining astringent vegetables," says Davy, 
 " in relation to their powers of tanning skin, it is neces- 
 sary to take into account not only the quantity they 
 contain of the substance precipitable by gelatine, but like- 
 
CHEMICAL THEORY OF THE TANNING PROCESS. z\ 
 
 wise the quantity and nature of the extractive matter; 
 and in some cases of comparison it is essential to employ 
 infusions of the same degree of concentration. It is evident 
 that of all the astringent substances which have been as 
 yet examined, catechu is that which contains the largest 
 proportion of tannin ; and supposing, according to common 
 estimation, that from 4 to 5 lbs. of common oak bark are 
 required to produce 1 lb. of leather, it appears from the 
 various synthetical experiments that about half a pound 
 of catechu would answer the same purpose." 
 
 Mr? Purkis found that 1 lb. of Bombay catechu was 
 equivalent to 7 or 8 lbs. of oak bark ; and that, allowing 
 for the difference in the composition of the different kinds 
 of leather, 1 lb. of catechu, for the common uses of the 
 tanner, would be nearly equal to 2^ lbs. of galls, to 7 lbs. of 
 Leicester willow, to 11 lbs. of Spanish chestnut bark, to 
 18 lbs. of elm bark, to 21 lbs. of common willow bark, and 
 to 3 lbs. of sumac. 
 
 Dr. Ure remarks,* "The older tanners, who prided 
 themselves on producing a substantial article, were so 
 much impressed with the advantages of slowly impreg- 
 nating skin with astringent matter that they employed no 
 concentrated infusion (ooze) in their pits, but stratified the 
 skins with abundance of ground bark, and covered them 
 with soft water, knowing that its active principles are very 
 soluble, and that, by being gradually extracted, they would 
 penetrate uniformly the whole of the animal fibres, instead 
 of acting chiefly upon the surface and making brittle 
 leather, as the strong infusions never fail to do. In fact, 
 100 lbs. of skin, quickly tanned in a strong infusion of 
 bark, produce 137 lbs. of leather; while 100 lbs., slowly 
 tanned in a weak infusion, produce only 117^ lbs. The 
 additional 19 \ lbs. weight in the former case serve merely 
 to swell the tanner's bill, while they deteriorate the leather 
 and cause it to contain much less of the textile animal 
 solid. Leather thus highly charged with tannin is, more- 
 over, so spongy as to allow moisture to pass through its 
 pores, to the great discomfort and danger of persons who 
 
 * "Dictionary of Arts, Manufactures," &c. By Andrew "Ore, M.D. 
 
23 LEATHER MANUFACTURE. 
 
 wear shoes made of it. That the saving of time and the 
 increase of product are temptations strong enough to 
 indtice many modern tanners to steep their skins in a 
 succession of strong infusions of bark is sufficiently intel- 
 ligible, but that any shoemaker should be so ignorant or 
 so foolish as to proclaim that his leather is made by a 
 process so injurious to its quality is unaccountably stupid." 
 During the process of tanning, more especially by the 
 modern system, in which infusions of bark and other 
 tanning materials are used, chemical decomposition of a 
 portion of the tannin takes place by a process of fermenta- 
 tion, by which gallic acid — a useless product to the tanner 
 — is formed. This will be considered in the chapter on 
 Gallic. Fermentation, and the various remedies for its pre- 
 vention duly given. 
 
CHAPTER II. 
 
 THE SKIY. 
 
 The Skin. — Structure of the Skin. — Mr. Ashe's Description of the Skin. — 
 Composition of the Skin. 
 
 The Skin. — It is of the first importance to the tanner 
 that he should be acquainted with the anatomical structure 
 of that part of the animal — the skin — the treatment of 
 which constitutes his art. This knowledge is more espe- 
 cially necessary, since not only does the cuticle, or outer 
 surface of the skin, resist the action of the tanning prin- 
 ciple, hut the underlying substance, the true shin, when 
 brought in contact with tan, or tannin, undergoes a defi- 
 nite chemical change, by which its whole character and 
 properties are completely altered. 
 
 Structure of the Skin. — The skin of animals consists of 
 two distinct layers, which are thus classified : 1. The 
 Cuticle, epidermis, or scarf skin; and 2. The Cutis, corium, 
 or true skin {cutis vera) . The cuticle varies in thickness in 
 different animals, and in different parts of the body ; it is 
 insoluble in water, alcohol, and dilute acids ; strong acids 
 soften it, and ultimately dissolve it, while solutions of 
 caustic alkalies, as soda and potassa, freely dissolve it, 
 even when very dilute. The cuticle readily absorbs cer- 
 tain colouring matters, which impart to it a permanent 
 dye. Between the cuticle and the corium is the areolar 
 tissue, formerly termed the rete mucosum, in which the 
 roots of the hair are embedded. This tissue contains the 
 colouring matter which gives to the skin its characteristic 
 tint, and which is much influenced by the action of light. 
 " The black skin of the African," says Brande, " the 
 brown of the Asiatic and American, and the pinkish -white 
 
24 LEATHER MANUFACTURE. 
 
 of the European, derive their colour from this peculiar 
 secretion deposited between the cutis and cuticle; the 
 nature of this substance has not been chemically investi- 
 gated, but it has been ascertained, in regard to the black of 
 the negro, that it admits of being bleached by chlorine." 
 
 The cutis, or true skin, is of a fibrous texture, almost 
 wholly soluble when boiled in water, and the solution, 
 when cold, forms a tremulous jelly, which is gelatine — the 
 chief constituent of the cutis, or that part of the skin 
 which, when submitted to the action of tannic acid, consti- 
 tutes tanned leather, or more properly, tanned skin. 
 
 The structure and functions of the human skin are 
 admirably described by Mr. Ashe in a valuable paper upon 
 this subject ; although objection may be taken to our 
 having chosen this author's description of the human skin 
 instead of giving that of the ox or other inferior animal, 
 we venture to suggest that for the purposes of the tanner, 
 who practically requires merely to know the structure of 
 the skin and its functions generally, without troubling him- 
 self about the comparative anatomy of the subject — the 
 full and minute description given by Mr. Ashe will enable 
 him to comprehend the true character of the delicate 
 fibrous structure of the cutis, which, when separated from 
 its cuticle, hair, and fleshy matters, constitutes the pelt or 
 part of the hide to be tanned. Moreover, when the fibrous 
 texture of the unhaired skin is thoroughly understood, the 
 tanner is better able to regulate and control its proper 
 treatment in the various stages of the several processes 
 which constitute the art of tanning. 
 
 Mr. Ashe's Description of the Skin. — " The cutis, or 
 true skin, rests upon a very fine interlaced or netted struc- 
 ture, called the areolar tissue, out of which, if we may so 
 express it, the granules and fibres of the skin are formed. 
 The cuticle, or scarf skin, is never of any great thickness 
 in any animal, but the true skin is of very variable thick- 
 ness. In the whale the cutis attains the thickness of about 
 an inch, which is the greatest known in any animal. The 
 cuticle consists of several layers of laminated scales, the 
 laminated form being best marked at the very surface, 
 
THE SKIN. *5 
 
 where the scales are constantly falling off, as a kind of 
 scarf, and are as constantly being renewed from below. 
 These scales are formed by the flattening out of granules, 
 more or less rounded, which is the form assumed by the 
 particles of the cuticle in its deeper layers. These granules 
 are at first nucleated* cells, and the colouring matter of 
 the skin resides in the nuclei ; and it was these granules 
 that were formerly described as a separate layer, under the 
 name of rete mucosum. They are very minute, being 
 about -g- o'oo" P ar ^ °^ an ind 1 i n diameter at first. Being 
 removed from below, as the flattened scales are removed 
 from above, they gradually approach the surface, and as 
 they do so they more and more lose the granular form, and 
 assume the scaly character, their diameter increasing 
 accordingly to about -q^ of an inch. Into the epidermis, 
 or cuticle, no nerves or blood vessels penetrate, and it is 
 nourished merely by the transudation f of the serum of the 
 blood through the walls of the vessels of the true skin and 
 subcutaneous areolar tissue. It is not itself sensitive, but 
 on the contrary, serves to blunt the too exquisite sensation 
 of the true skin, which is much more highly organised, 
 and consists of two kinds of tissue, namely, white and 
 yellow fibres, the former being denser and more resisting, 
 and being therefore present in greater quantity wherever 
 resistance is most needed, as in the palm of the hand and 
 sole of the foot ; while the yellow fibres are a highly elastic 
 tissue, owing to their minute fibrillse being arranged in 
 interlacing curves ; and the fibres cross each other repeat- 
 edly, and branch, so as to form lozenge-shaped interstices, 
 which are filled up principally by the white fibres. The 
 yellow fibres accordingly, as might have been anticipated, 
 exist in greater abundance where elasticity is a special 
 requirement, as at the flexures of the joints, the lips, &c. 
 The uppermost surface of the cutis, or true skin, is strangely 
 uneven and irregular, being elevated into a vast number of 
 minute papillae, which are about -y^- of an inch in height 
 and -jyo" °f an ^ ncn i n diameter. Minute as these little 
 
 * From nucleus, a body round which, anything is collected or deposited. 
 1 Passing through as vapour. 
 
26 
 
 LEATHER MANUFACTURE. 
 
 papillae are, each possesses a ramification of vascular capil- 
 laries, and of nerve fibres, being, in fact, the essential 
 agents in the sense of touch, for that is the function of 
 these papillae. The skin of the tongue in men and animals 
 shows the papillae larger than in any other part of the 
 body." The accompanying illustration (Fig. 1) represents 
 
 a highly magnified view of 
 the skin, with its secreting 
 glands and perspiratory 
 ducts, a is the cuticle, or 
 scarf skin ; b the areolar 
 tissue, and c the cutis, or 
 true skin. 
 
 " The true skin is perfo- 
 rated by perspiratory ducts 
 (/), and when the hand is 
 warm the perspiration may 
 be observed, even with the 
 naked eye, to issue from 
 them, forming minute shin- 
 ing dots. The glands (e) by 
 which the perspiration is 
 secreted, are seated at the under surface of the true skin, 
 each embedded in a cavity of it. These glands are con- 
 sequently to be regarded as true excretory organs, re- 
 moving from the blood materials that are no longer 
 wanted, and which, if retained, would be injurious. About 
 2,500 of these ducts are found in the square inch of 
 the skin. 
 
 "Another kind of gland is also formed in the skin, in 
 connection with the hairs, and engaged in their nutrition ; 
 these glands are called sebaceous glands (d) ; the ducts of 
 these glands are not spiral, and they open generally into the 
 hair follicles or pits which the hair grows out of, situated 
 in the subcutaneous areolar tissue ; these glands lubricate 
 the skin, and so maintain its elasticity : and they also 
 eliminate hydrocarbons from the skin." 
 
 It will be seen from the above observations that the 
 direction of the secreted fluids of the true skin is outward, 
 
 Fie. 1, 
 
THE SKIN. 27 
 
 or in the direction of the cuticle, consequently the absorp- 
 tion of tanning material would be more powerful at the 
 flesh side than at the grain side of the skin. 
 
 Composition of the Skin. — A piece of fresh skin, freed 
 on its internal side from fat and cellular tissue, and on its 
 external side from the epidermis (cuticle) and the mucous 
 membrane (areolar tissue), which lies between the epider- 
 mis and the true skin, contains about 43 per cent, of solid 
 matter, the remainder being water. Of the solid matter 
 about 32 per cent, of the weight of the humid skin is the 
 fibrous and cellular tissue, and a little fatty matter, each 
 of which is insoluble in cold water ; 1*5 per cent, is unco- 
 agulated albumen. About 1 per cent, is a variety of 
 extractive matter, soluble in water and alcohol, and 7 "5 per 
 cent, is another kind of extractive matter, soluble in water, 
 but insoluble in alcohol. — Wcinholt. 
 
 Nearly the whole of the albumen and other matters 
 capable of being dissolved by cold water may be separated 
 by digesting the skin in that liquid. When the washed 
 skin is dried and digested in ether, a small quantity of 
 fatty matter is dissolved out. By digestion in boiling 
 water the greater part of the true skin becomes altered in 
 properties and dissolved ; only some vascular and nervous 
 filaments, with a little fat, remaining undissolved, and the 
 solution, when slowly evaporated, leaves a residue of gela- 
 tine, or glue. — Parnell. According to Berzelius, gelatine 
 does not exist, as such, in the living body, but several animal 
 tissues, such as skin, cartilages, tendons, the serous mem- 
 branes and bones, are susceptible of being converted into it 
 by the action of boiling water. The term gelatinous tissue 
 is commonly used to designate all animal tissues which are 
 convertible into gelatine by such a process. Dilute acids 
 and alkalies possess the property of converting gelatinous 
 tissues into gelatine even at the ordinary temperature. 
 
CHAPTER III. 
 
 HIDES AND SKINS. 
 
 Classification of the Skins of Animals. — Condition of Hides and Skins. — 
 Hides. — Native Hides. — Dried Hides. — Salted Hides. — Dried Salted 
 Hides. — Selection of Hides. — Warbles. — Abusive Treatment of Raw- 
 Hides. — Kips. — Buffalo Hides. — Horse Hides.- — Ass and Mule Hides. 
 — Hippopotamus Hides. — Calves' Skins. — Sheep Skins. — Lamb Skins. 
 — Goat Skins. — Kid Skins. — Hog and Pig Skins. — Seal Skins. — Deer 
 Skins. — Porpoise Skins. — Serpent and Crocodile Skins. 
 
 Classification of the Skins of Animals. — These are 
 known, commercially, under three different heads, namely 
 — 1. Hides, or the skins of the larger and full-grown 
 animals, as the ox, cow, bull, buffalo, horse, and hijDpopo- 
 tamus ; 2. Kips, or the skins of the smaller Indian 
 animals of the bovine class ; and 3. Shins, as those of the 
 smaller animals, such as the calf, sheep, goat, deer, &c. 
 The skins which are most extensively used in the manu- 
 facture of the various kinds of leather are those of the 
 ox, cow, bull, horse, calf, sheep, goat, kid, pig, deer, seal, 
 and kips; but the skins of crocodiles, alligators, and 
 even serpents are also employed for making certain kinds 
 of fancy leathers. 
 
 Condition of Hides and Skins. — The quality of hides 
 and skins is greatly influenced by the conditions under 
 which the animal has grown, the nature of its food, the 
 variety of breed, climate, the state of its constitution, its 
 age, and the time of year at which it has been slaughtered. 
 The hides of the larger oxen form, when tanned, a stouter 
 and heavier leather than those of cows, especially if the 
 latter are from old animals or from those which have 
 calved several times. The hides of bulls are of coarser 
 grain and thinner in the back, or butt, than those of oxen 
 and heifers, or young cows, although they are stouter in 
 
HIDES AND SKINS. 29 
 
 the neck and certain parts of the belly. Muspratt says, 
 " Hides of animals dying in a state of disease are found to 
 be much inferior to those of healthy ones of the same 
 class, although the apparent difference is not very marked 
 before tanning. No very definite criteria are known to 
 guide the purchaser in distinguishing the quality of hides 
 and skins. If the hide be thin, flabby, soft, and will not 
 bear handling, then such a one will not make good leather ; 
 but should it present the opposite qualities, it may be con- 
 fidently expected to be a good article. It has been remarked 
 of sheep that the skin gains in thickness and quality con- 
 siderably in the course of a few days after shearing. 5 ' 
 
 Hides. — Under this heading are included the skins of 
 oxen, cows, horses, and buffaloes. The hides are distin- 
 guished as — 1. Fresh, or green hides, or those which come 
 from the slaughter-houses of Great Britain ; 2. Dried hides, 
 as imported from Buenos Ayres, the Cape of Good Hope, 
 &c. ; 3. Salted hides, those which come from Bio Grande, 
 Biver Blate, Australia, &c. ; and 4. Dried and salted hides, 
 as imported from Brazil, Mauritius, West Indies, and other 
 countries. Although the hides of home production are held 
 in the highest estimation, the imported dried and salted 
 hides, when subjected to certain preparatory processes to 
 bring them into the condition of green hides, form, when 
 tanned, most excellent leather. The trouble, and labour 
 involved in softening the dried skins naturally favours a 
 more ready market for those of home production ; neverthe- 
 less we import enormous quantities of hides and skins from all 
 parts of the world, but more especially from South America. 
 The vast pampas through which the Biver Blate (or Silver 
 Biver) and its tributaries flow, yield boundless pastures ■ 
 for wild or partially wild oxen and horses, which have 
 been estimated to number nearly 25,000,000. Indeed, the 
 climate of this district seems specially suited to the rearing 
 of cattle, which are descended from the tame animals first 
 introduced by the Spaniards after Columbus' discovery. 
 The Buenos Ayres hides obtained from the most southern 
 states are considered stouter and of finer texture than those 
 of Uruguay or Bio Grande. The hides from the more tern- 
 
30 LEATHER MANUFACTURE. 
 
 perate regions are salted, and exported as wet salted, while 
 those from the tropics are generally dried in the sun, or 
 salted and dried. Dry salted hides are largely exported 
 from Brazil, Mauritius, Madagascar, &c. 
 
 Native Hides, or those of home slaughter, differ greatly 
 in substance, size, and texture ; while those from the south 
 of England yield large and heavy hides of fine texture and 
 grain, they are much thinner than the smaller hides of the 
 north of Scotland. The fattening of cattle for the produc- 
 tion of good beef, to suit the English market, renders the 
 hides, although of great size and weight, considerably 
 thinner than those from cattle subjected to less culture. 
 The hides of heifers are preferred to those of cows which 
 have calved several times, owing to the latter being thinner 
 and of poorer substance. Bull hides are not liked by 
 the tanner, owing to their Want of uniformity in sub- 
 stance, being thin in the back and thick at the shoulders 
 and the surrounding parts called offal. Ox hides generally 
 weigh from 60 lbs.* to 120 lbs., cow hides from 40 lbs. to 
 80 lbs., and kips from 20 lbs. to 22 lbs. 
 
 Dried Hides — These are sometimes called "flint" 
 hides, from their excessive hardness. It is well known 
 that when skins are dried in the sun they become nearly 
 as hard as horn, and when in this condition, they require 
 much soaking, rubbing, and beating to bring them to the 
 proper state for treatment in the lime pits. The imported 
 dried hides of Buenos Ayres, Monte Yideo, and other 
 countries are, however, extensively used by the tanner, 
 and from them leather of very good quality is produced. 
 
 Salted Hides. — The salted hides from South America 
 come into this country in a moist condition, a large quan- 
 tity of salt being stratified between each hide. Since the 
 salt, however, adds considerably to the weight of the hides, 
 it is usual for the intending purchaser, when inspecting 
 them at the docks while the vessel is unloading, to turn 
 them over before having them weighed, to free them 
 as far as possible from the loose salt ; while doing so he 
 
 * Hides are reckoned small, and of less value in proportion, when they 
 weigh 60 lbs. and under. Over this weight they rank as large hides. 
 
HIDES AND SKINS. 31 
 
 is able at the same time to form a fail judgment as to 
 their condition. These hides are frequently impaired by 
 the barbarous system of branding adopted by the South 
 American cattle owners, sometimes as many as half-a- 
 dozen brands being visible on a single hide. These im- 
 pressions of the branding-iron render such parts of the 
 hide useless when tanned, whereby the manufacturer neces- 
 sarily suffers loss. Unsuccessful attempts have been made 
 from time to time to induce cattle owners to adopt some 
 less brutal and injurious system of marking their cattle. 
 Probat)ly the most effectual remedy for the evil would be 
 to reject all such heavily branded hides. 
 
 Dried Salted Hides. — The hides from Brazil, Mauritius, 
 West Indies, and the Cape sometimes come into the market 
 both dried and salted, in which condition they are more 
 readily brought to a pliant state than the so-called " flint," 
 or dry hides. 
 
 Selection of Hides. — Although judgment based upon 
 practical experience is the only reliable guide in the selec- 
 tion of hides and skins, there are several points to which 
 special attention may be directed. 1. The hide should pre- 
 sent the appearance of having been well flayed, free from 
 cuts or gashes produced by the slaughterer's knife, and pre- 
 sent little or no sign of decomposition. 2. The hide should 
 not be loose and flabby, but generally firm in substance. 
 3. Besides being stout in the back, or butt, it should ex- 
 hibit this quality, though in a gradually diminishing 
 degree, right up to the shoulder. 4. The hide should be 
 free, or as free as possible, from icarbles or warble marks, 
 more especially if to be used in the preparation of harness, 
 bucket, or hose leather. These defects, which are pro- 
 duced by the larva, or grub, of the bot, or gadfly (oestrus 
 bovis), sometimes cause serious injury to the most important 
 portion of the hide — the back ; and although warbles are 
 of less consequence in the production of sole leather, they 
 would be fatal to leather which is required to be wind or 
 water tight. Since the subject of warbles is a very im- 
 portant one, and has received much attention from ento- 
 mologists and others, it may be well to consider the origin 
 
32 LEATHER MANUFACTURE. 
 
 and nature of the destructive parasites which produce the 
 holes, or warbles, in the hides of cattle. 
 
 Warbles. — Some persons seem to have entertained the 
 idea that the grub which perforates the skin of oxen is de- 
 veloped much in the same way as the trichince, from which 
 the devourers of uncooked ham and bacon, and German 
 sausage, suffer — chiefly in Germany — in the form of disease 
 known as trichinosis. We think, however, that the most 
 reliable evidence is in favour of the entomologists, who have 
 universally attributed the pest to the gadfly, an insect 
 which is well known to haunt the meadows in which cattle 
 feed, and to cause the animals much pain and suffering. 
 It appears to be conclusive that the gadfly first pierces the 
 skin with an organ termed an ovipositor — much in the same 
 way that a wasp's sting is introduced — and that in the 
 hole thus formed an egg is deposited, which after a time 
 becomes hatched. The existence of the liberated grub 
 beneath the skin causes great irritation, and an open sore 
 is established, which extends as the larva increases in size. 
 When it has become fully matured, it escapes from the 
 hole, and falls to the ground, where it in time changes to 
 the pupa, or chrysalis state, from which, in the following 
 season, the pretty but dreaded new-born fly emerges to 
 carry on the war with the bovine race. The distinguished 
 naturalist, Sir John Lubbock, says, " The gadfly deposits 
 its eggs upon the bodies of animals, and the grub feeds 
 inward when hatched." Another writer in The World 
 of Insects says : " The gadfly at certain seasons attacks 
 oxen, not to bite and suck their blood, but to deposit its 
 eggs in the hides of the cattle — an operation which is not 
 put into execution without occasioning considerable pain. 
 The circular hole thus made always continues open, and 
 increases in diameter as the larva increases in size, which 
 thus enables a continual supply of fresh air * to reach the 
 
 * It may be doubtful whether air is really necessary to the existence 
 of these maggots, since the trichince, tape worms, ascarides, and other 
 well-known parasites seem to get on very well in the animal system 
 without troubling themselves about a "breath of fresh air." An animal 
 that thrives upon purulent and decomposing matter may be said to be not 
 very particular as to " fresh air." 
 
HIDES AND SKINS. 
 
 33 
 
 insect. But although they torment and terrify the cattle 
 during the time of ovipositing, they do them in reality no 
 material harm; indeed tanners prefer hides that have 
 the greatest number of bot holes, considering them the 
 strongest and best, which indeed they are, as the gadfly 
 never attacks any but young and healthy subjects." This 
 seems an extraordinary statement, and one which the 
 mind cannot readily accept as based upon reasonable 
 ground. That young and healthy animals should be pre- 
 ferred by the anxious parent for the boarding and lodging 
 of her progeny is quite natural and to be applauded ; but 
 that it should be stated that tanners prefer perforated to 
 sound hides seems inexplicable, more especially as it is 
 so very well known that how to get rid of warbles has 
 been one of the most anxious subjects of inquiry connected 
 with the trade for many years. 
 
 Referring to the ox-bot or ox-gadfly, another writer ob- 
 serves — " It is a beautiful insect, not quite half-an-inch 
 long, and thicker in proportion than the horse-bot. It 
 has brown, unspotted wings, the face whitish, the crown 
 of the head brown, the thorax black, the abdomen whitish, 
 with a broad black band round the middle, and yellow 
 hairs at the extremity, where also the female has an ovi- 
 positor — a remarkable organ, formed of a horny substance, 
 consisting of four tubes, retractile within one another, like 
 the pieces of a telescope, and the last of them terminating 
 in five points, three of which are longer than the others, 
 and hooked. By means of this organ, a small round hole 
 is pierced in the hide of an ox's back, in which an egg is 
 deposited. The fly is very quick in depositing her egg — 
 not remaining on the back of the animal more than a few 
 seconds. Cattle exhibit great alarm and excitement at 
 the presence of the gadfly, and rush wildly about with 
 head stretched forward, and tail stuck out, to escape from 
 their tormentor. The further injury done by this insect 
 is not, however, usually great, the larva — a little pearl- 
 white maggot feeding upon the juices of the skin — caus- 
 ing a swelling, called a icarble, forming a sort of sac, 
 within which it lives and grows amidst a kind of purulent 
 
 D 
 
34 LEATHER MANUFACTURE. 
 
 matter suited to its appetite, and from which it usually 
 emerges, leaving a small sore ; and, like the horse-bot, 
 undergoes its further transformation in the ground." 
 Again, Miss Eleanor A. Ormerod, who had worked assidu- 
 ously with the farmers in their efforts to diminish the 
 injuries caused by insects to their crops, writes : " The 
 oestrus bovis is a largish two-winged fly, and the female 
 lays her eggs on the backs of horned cattle. The maggots 
 from these, by feeding on the flesh, cause tumours, with 
 an opening at which orifice the tail end of the maggot is 
 usually exposed. When full fed, the larva, or maggot, 
 drags itself out of the tumour and falls to the ground, 
 where it changes to the pupa or chrysalis state, from which 
 in due time the rather handsome fly emerges." 
 
 The above observations clearly prove the origin of 
 warbles, and when it is borne in mind that, besides the 
 positive injury done to the hide, the animal must suffer 
 great and continual torture, it would be well if our agri- 
 cultural chemists and scientific farmers were to devote 
 special attention to the subject, with a view to discover 
 some means of rendering the skin of young cattle less 
 attractive to the gadfly. This might be accomplished, 
 possibly, by brushing over that part of the skin (the back) 
 which is generally selected as the depository of the gad- 
 fly's eggs, some oil, or solution of such substances as 
 are known to be objectionable to insects, but harmless to 
 the animals themselves. It is well known, for example, 
 that the smell of the oil of birch is much disliked by most 
 insects, as also is creosote, or water impregnated with it. 
 Again, powerful bitters, as wormwood, quassia, and aloes, 
 are repugnant to some species of insects. If, therefore, 
 during that period of the year when the gadfly makes its 
 appearance, the backs of cattle were brushed over with one 
 or other of these agents, is it not probable that the fly, 
 recognising a foreign flavour or odour upon the skin of the 
 animal, would abandon it and fly from beast to beast in 
 search of one more suited to its purpose ? Doubtless the 
 gadflies emerge from the shell of the chrysalis with toler- 
 able regularity as to time, in which case the appearance of 
 
HIDES AND SKINS. 35 
 
 the first insect of the season would be a signal for the 
 application of any agent which it was desired to try with a 
 view to determine whether a remedy for warbles could be 
 found in the direction we have indicated. 
 
 Abusive Treatment of Raw Hides. — Ordinary care- 
 lessness and even rough usage, of a raw material so difficult 
 to handle as the hide of such a large animal as the ox, can 
 neither be wondered at nor prevented, but apart from this, 
 hides are too often abused, in various ways, to such a degree 
 as greatly to reduce their value to the tanner. Some years 
 ago M? H. Lange, a Cordovan leather tanner, at a meeting 
 of the trade at Oschatz, exposed the abuses to which hides 
 were subject before they fell into the hands of the tanner ; 
 and since his observations are applicable to all times and 
 places, their reproduction here will doubtless be acceptable 
 to our readers. 
 
 " M. Lange expressed his regret that in the prepara- 
 tion of the hide for trade purposes, raw hides and skins 
 laboured under great disadvantages, owing to the farmers' 
 and butchers' handling, inasmuch as this was not carefully 
 done with a view to the future operations to be undergone 
 by the raw material. The bark and white tanners present 
 at the meeting, also gave expression to the united wish 
 that through making known the manipulations which 
 experience has proved to be the most simple and at the 
 same time the most efficacious, hides or skins may be 
 delivered in a condition perfectly suitable to the process of 
 manufacture, and the evils specified may hereafter be done 
 away with as far as possible. It too often happens that 
 hides and skins of slaughtered animals, as of those that 
 have died from natural causes, are not at once taken off, 
 but left for days on the carcase. This is in the highest 
 degree detrimental to the hides, as they acquire thin and 
 defective spots through decomposition going on in the 
 carcase, or the worms which are forming in the interior of 
 the animal [query] work destructively upon the hides. 
 
 " Great damage is also caused, although not of so serious 
 a nature, if, in flaying, the work is not done with all due 
 care. The bits of flesh and fat, which are too often allowed 
 
36 LEATHER MANUFACTURE. 
 
 to remain adhering to the hides and skins, become at once 
 decayed and communicate decay to the skin, which is 
 injured or eaten away in spots, becoming consequently, 
 and subsequently, very thin, or even worn into holes. Such 
 damage is noticeable more especially after manufacture, 
 when the leather is found bad in appearance or pitted 
 with dark spots, as in the case of coloured leather. Leaving 
 these defects out of the question, the suppleness and dura- 
 bility of the leather itself will be injuriously affected if the 
 skins are not suitably and carefully treated in drying and 
 hanging up, by the premature shrinking and imperfect 
 drying of the material. As evidence that the evils just 
 mentioned, arising from improper treatment, are of more 
 importance than is generally thought, M. Lange states 
 that the sheepskins received in the summer season often 
 yield barely one-third of the material perfectly adapted to 
 the manufacture of imitation Morocco leather. 
 
 " In view of these evils, and in order to promote the 
 interests of the leather trade, the following points are to 
 be urgently recommended to the slaughterers in flaying 
 hides and skins : — 
 
 " 1. Immediately after the death of the animal the hide 
 or skin should be carefully taken off. 
 
 " 2. The fleshy or fatty portions still adhering to the 
 skin should be detached, down to the smallest pieces. 
 
 " 3. The hide should, without the least delay, be hung 
 up in a very airy place, and one not exposed to damp, with 
 the hair side inward, so that the draught of air may play 
 upon the entire length of the flesh side of the hide. 
 
 " 4. In order to prevent the hide from shrinking, the head 
 and tail ends should be stretched out and nailed to the pole. 
 
 " 5. The hoofs and legs should be spread with skewers 
 on both sides. 
 
 " 6. The flaying of the hide should not be entrusted to 
 inexperienced persons; for unless a certain dexterity is 
 brought into operation, the value of the skin will be con- 
 siderably lessened. Only by observing these directions, 
 can 'the skins and hides be properly dried and delivered 
 free from defects, suitable for valuable use. The benefits 
 
HIDES AND SKINS. 37 
 
 that will accrue to the whole leather trade by following 
 such a course canuot be rated too highly, for not only will it 
 secure a serviceable material to manufacturers, but also a 
 large quantity of hides and skins will be saved from 
 destruction, and the market will be better and more fully 
 supplied. A further consequence will also be that a better 
 manufactured article will be produced and lower prices 
 established." — Dussauce's Treatise. 
 
 A few years ago Mr. George Middleton, manager of 
 the Midland Counties' Butchers' Hide, Skin, &c, Com- 
 pany (Limited), suggested the plan of issuing cheques to 
 slaughtermen, entitling them to a reward of sixpence for 
 each hide taken by the company flayed to its satisfaction. 
 In addition to this, the master butchers agreed to give an 
 extra sixpence per hide, as a reward for careful flaying, 
 thus giving the slaughtermen one shilling per hide for 
 performing their work with extra, that is proper, care. 
 
 Kips, or skins of the younger and smaller animals, are 
 largely imported from the East Indies, the Cape, Australia, 
 North and South America, and elsewhere. From the East 
 Indies they arrive either dry, dry salted, or brined — that 
 is, simply salted. The E. I. kips are the skins of a small 
 breed of oxen, and being derived from full-grown animals 
 they are in reality hides. Besides being imported in either 
 of the above conditions, a large quantity reach our market 
 in the tanned state. The importation of E. I. kips amounts 
 to millions of skins annually. Kips are also imported 
 from the countries surrounding the Baltic, but these 
 are generally obtained from animals slaughtered when 
 young, and therefore are more of the character of skins 
 than hides. The smaller and inferior varieties of kips 
 and calfskins are tanned for the purposes of the book- 
 binder and glover, and also in the preparation of 
 leather for uppers of the lighter kinds of boots and 
 shoes. 
 
 Buffalo Hides. — These are imported from various parts 
 of the East Indies — as Bombay, Calcutta, Batavia, Kur- 
 rachee, &c. These hides make an inferior kind of sole 
 leather, and are tanned in the same way as ox hides. Eor 
 
38 LEATHER MANUFACTURE. 
 
 certain purposes, however, they are tanned in a peculiar 
 manner, and then form what is known as buff, or belt 
 leather, which possesses superior strength to the same article 
 prepared from cow hides. The annual importations have 
 sometimes amounted to upwards of 300,000 hides. 
 
 Horse Hides. — The best horse hides are those which 
 are imported from the River Plate, Rio Grande, and other 
 parts of South America. The wild horses of the pampas, 
 which are captured and slaughtered chiefly for the hides 
 and fat, furnish a vast supply of hides, which are greatly 
 superior to those of our own market, which are generally 
 from old and worn-out animals. The skin of the horse is 
 nrach inferior to that of the ox, or even cow, as to strength, 
 texture, and thickness, and is therefore not suitable for 
 making sole leather ; a small portion of the back, or butt, 
 nearest the animal's rump, however, is generally cut away, 
 and when tanned is employed for upper leather (" crap "). 
 The better qualities of horse hides are tanned for uppers 
 of boots and shoes, but the chief purpose to which they 
 are applied is in making Cordovan, or enamelled leather. 
 For this purpose the pelts are split by machinery, which 
 reduces them to any required thinness. These hides are 
 also tawed, or alumed, and converted into white leather 
 for workmen's aprons, for the thongs of common whips, 
 and other useful purposes. 
 
 Ass and Mule Hides. — When tanned, these hides form 
 what is known as Shagreen, or Shagrin. 
 
 Hippopotamus Hides. — Only a limited number of these 
 skins come into the market, being imported from the south 
 of Africa. They are of remarkable thickness, and when 
 tanned are exceedingly hard. The principal purposes to 
 which the tanned hides are applied is for implements used 
 in washing and bleaching cotton and linen goods, and for 
 making circular "buffs" for polishing brass and other 
 metals. Walrus hides are also used, when tanned, for 
 similar purposes. 
 
 Calves' Skins, of home produce, are of very superior 
 quality, and, when tanned with oak bark, produce a 
 leather which is very extensively used for the uppers of 
 
HIDES AND SKINS. 39 
 
 shoes and for boot fronts. In France, which is famous for 
 the excellence of its calf-skin leather, the calves are 
 slaughtered when about five or six months old. 
 
 Sheep Skins. — The supply of sheep skins in the home 
 market is very extensive, and besides this source of supply 
 an immense number are imported from South America, the 
 Cape, Australia, and many other countries : a very con- 
 siderable proportion come to us in the tanned state. 
 Although sheep skins produce but a very weak, spongy 
 leather, they are applied to a great variety of purposes. 
 When tanned with bark, they constitute bazils, and are 
 used for making slippers, and also as bellows-leather ; 
 when tawed, or prepared with alum and salt, they form 
 what is termed white leather, which is much used by drug- 
 gists, and also for workmen s aprons. Sheep skins are very 
 often subjected to the operation called splitting, when the 
 grain side is tanned with sumac, and dyed, and is after- 
 wards worked up as imitation morocco, roan, or shiver, into 
 covers for pocket-books, for hat linings, &c. The flesh side 
 is converted into white leather for druggists' use, or into 
 chamois, or shammy leather ; for the former, however, lamb 
 skins are most generally employed. Sheep skins are some- 
 times tanned with the wool attached, and converted into 
 mats ; or tawed, and made into housings. For these pur- 
 poses the best skins are selected, and those with the longest 
 and most beautiful fleece are chosen by preference. 
 
 Lambs' Skins are very extensively used in the prepara- 
 tion of leather by the process of taioing, for glove-making, as 
 a substitute for kid leather, and for various other purposes. 
 Besides the very large number produced in this country, 
 great quantities of lambs' skins are annually imported. 
 There is a great difference in the quality of these 
 skins ; those from the animals slaughtered shortly after 
 birth possess an exceedingly fine grain and are sus- 
 ceptible of a very uniform dye — an important feature in 
 skins used for ladies' gloves. This extreme delicacy of 
 texture is retained by the skin of lambs until after they 
 are a month old, from which period they gradually lose it. 
 In the south of France and in Italy considerable numbers 
 
46 LEATHER MANUFACTURE. 
 
 of lambs are killed averaging four weeks old ; leather pre- 
 pared from these skins is largely used for " kid " gloves. 
 
 Goat Skins. — A very extensive trade is carried on in 
 Great Britain and Ireland in these skins, and also in the 
 tanned and tawed leather produced from them. In 
 Ireland a large number of skins of native produce are 
 used, but Great Britain is supplied chiefly by imports 
 from Switzerland, and the Yalley of the Bhine, and also 
 from India and the Cape of Good Hope, from which 
 latter places they are imported in the dry state. Millions 
 of these skins, however, come into the British market 
 already tanned and tawed from these countries. The Swiss 
 goat skins are most highly esteemed, owing to the very 
 fine, close and uniform texture of the grain, which enables 
 the dyer to impart a brilliant and permanent colour ; the 
 leather prepared from Swiss skins is said to be stronger 
 and more durable than any other manufactured from goat 
 skins. A very considerable number of these skins are 
 annually converted into morocco leather for various uses 
 in the different branches of the trade. The goat skin 
 tanned and dyed on the grain side constitutes true morocco 
 leather. Mogadore skins are made into a kind of black 
 morocco, called Cordovan, in consequence of the first sup- 
 plies of the article being obtained from Spain and Cordova, 
 where the Moors originally brought the manufacture to 
 great perfection. The sound skins which arrive from the 
 Cape of Good Hope, are much larger and superior in 
 strength and thickness to any other variety. East India 
 skins are small and light, and are generally converted into 
 chrome leather chiefly used for ladies' shoes. Those 
 from Mexico, known in the American market as Tampico 
 skins, bear a very high character. Compared with sheep 
 skins, those of goats are much superior in texture, 
 strength, and durability. Goat skins are occasionally 
 prepared so as to imitate chamois leather, and applied to 
 most purposes to which the latter is adapted ; and like- 
 wise with the hair on, and used for matting. — Muspratt. 
 
 Kid Skins, converted into leather by the process of 
 tawing, are very extensively used in the manufacture of 
 
HIDES AND SKINS. 41 
 
 gloves, and also for slippers, or light shoes ; by druggists 
 for covering the corks of bottles, and for other useful 
 purposes. The kid skins of France — from which the 
 famous " French kid " gloves are made — have always 
 been held in high estimation, as also are those of Ireland. 
 After the animal begins to feed upon herbage, the 
 skin loses in delicacy of texture, and therefore becomes 
 unsuited for the finest gloves. There can be no doubt 
 whatever that from the time the young animal ceases to 
 derive its sustenance from the mother, and feeds upon 
 vegetable substances, a greater degree of solidity and 
 firmness of texture is acquired by the skin, as also by all 
 other parts of the body, and as a consequence the elasticity 
 and extreme fineness and delicacy in texture of the skin 
 gradually become deteriorated. 
 
 Hog and Pig Skins. — The practice of skinning swine 
 is carried on in Scotland, and also on the Continent, and 
 the skins, when tanned, form a very light and porous, but 
 still very tough and durable leather, which is extensively 
 used by harness makers, and also for the seats of saddles. 
 On the Continent the hide is dressed with the hair on, and 
 is employed for covering portmanteaus, knapsacks, &c. 
 Pig skin is also used for leather breeches, but not to such 
 an extent as formerly. 
 
 Seal Skins. — These valuable skins are imported into 
 this country in very considerable quantities, from British 
 North America, Newfoundland, the United States, the 
 Whale Fisheries, Norway, the Cape of Grood Hope, and 
 other localities. The skin of the seal is light, and of very 
 close texture, and when properly tanned is considered to 
 produce a leather of greater strength in proportion to its 
 weight than any other kind of leather. Seal skins are 
 commonly made into black enamelled leather, for ladies' 
 shoes and boots, and the stouter varieties are used for the 
 uppers of hunting and riding boots, knapsacks, &c. Seal 
 skins are frequently merely dressed, with the fur on, for 
 ladies' jackets and muffs, and various articles of clothing, 
 as waistcoats, caps, &c. 
 
 Deer Skins are much used for making gloves and cha- 
 
42 LEATHER MANUFACTURE. 
 
 mois leather, and are prepared by the tawing process, in 
 the same manner as sheep and goat skins. The chief 
 manufacture in connection with deer skins is carried on in 
 the United States, and is comparatively unimportant in 
 this country. 
 
 Porpoise Skins. — These skins are now being much 
 used for uppers of boots, for which purpose they are admi- 
 rably suited, since, when tanned, they yield a very supple 
 and durable leather. Round and flat laces prepared from 
 these skins are exceedingly tough and strong. In Canada 
 the skins of the white porpoise have been tanned into 
 leather, which is said to be soft, strong, and of a beautiful 
 finish. 
 
 Serpent and Crocodile Skins. — During the past few 
 years specimens of tanned serpent skins have entered the 
 market, as also those of the crocodile and alligator, and 
 at the period at which we are writing, reticules, purses, 
 and bags formed of crocodile and alligator skins are freely 
 exposed for sale. Indeed, so great is the demand for this 
 variety of ornamental leather that close imitations of the 
 various skins are produced by means of the electrotype 
 process. (See page 432.) 
 
CHAPTER IV. 
 
 TANNIN OR TANNIC ACID. 
 
 Tannin or Tannic Acid. — Preparation of Tannic Acid. Pelouze's Process 
 — Berzelius' Process. — Bouillon-Legrange's Process. — Merat-Guillot's 
 Process. — Dize's Process. — Deyeux's Process. — Proust's Process. — 
 Serturner's Process. — Schering's Process. — Badvil and Lienders' 
 Process. — MM. Coez's Process. — Kohlrausch's Process. — Properties 
 of Tannic Acid. — Parnell's Views. — Pure Tannic Acid. — Reactions 
 of Tannic Acid. — Table of the Percentage of Tannin in Vegetable 
 Substances. — Morfit's Observations. — Artificial Tannin. 
 
 Tannin, or Tannic Acid. — This powerful astringent 
 vegetable principle, which is also known by the names of 
 Tan and GaUo-tannic acid, exists in those excrescences called 
 Gall nuts, which are found upon certain varieties of oak, 
 and some other plants, as the Tamarisk. It also occurs in 
 a great number of trees and plants. Galls are formed by 
 the female of the insect Cynips (or Diplolepsis) Gallce tinc- 
 torum, piercing the buds of a species of oak named Querents 
 infectoria, and there depositing its eggs. These producing 
 irritation, cause the juices of the plant to flow towards 
 the wound, and the subsequent enlargement of the part, 
 in the form of a vegetable tumour, or gall, round the 
 larva. This grub, when fully developed, escapes by a 
 hole which it perforates in the gall. The Quercus infectoria. 
 is the principal species of oak which yields the nut-galls of 
 commerce. 
 
 Preparation of Tannic Acid, Pelouze's Process. — 
 By this process, tannic acid is obtained by means of a per- 
 colator, a (Fig. 2) fitted into a receiver b. The percolator 
 is a cylindrical glass vessel, open at both ends, the upper 
 opening being fitted with an air-tight stopper, anr* the 
 
44 
 
 LEATHER MANUFACTURE. 
 
 lower end adjusted to the neck of the glass receiver b. 
 The upper vessel, or percolator, is about half filled with 
 coarsely-powdered galls, which are prevented from falling 
 through the lower opening by a plug of 
 cotton, and the powder is then covered, in 
 successive portions, with ether, which has 
 been previously shaken up with a little 
 water.* The stopper is now inserted in 
 the mouth of the percolator, and the mix- 
 ture allowed to digest for several hours, 
 after which the stopper is withdrawn, 
 and the liquid allowed to filter into the 
 receiver beneath. "When all the liquid 
 has passed through, the powdered galls 
 are washed with more ether introduced at 
 the top as before. After standing for a 
 short time, the filtered liquor will be found 
 to separate into two distinct strata, of 
 unequal density. The tannic acid and 
 gallic acid, being both extracted by the 
 mixture of ether and water, now sepa- 
 rate ; the lower stratum being a solu- 
 tion of tannin (generally of an amber 
 colour) in water, and the upper stratum an 
 etherial solution of other substances con- 
 tained in the galls, the most important 
 of which is Gallic acid. The two solutions are next sepa- 
 rated; the aqueous solution of tannin is gently evapo- 
 rated to dryness and finally exposed to an oven heat, 
 at a temperature not exceeding 212° Fahr. The result is 
 an amorphous, or uncrystallised mass of tannin, nearly if 
 not quite pure, the yield being frequently about 40 to 45 
 per cent, of the weight of galls used. The ether in the 
 lighter liquid is recovered by distillation, over a water 
 bath, with the aid of a Liebig's condenser, supplied with 
 ice-cold water. 
 
 Berzelius' Process. — A hot infusion of galls is first 
 
 * It is absolutely necessary that the ether should he agitated with 
 water, otherwise not a fraction of tannin will he obtained. 
 
 Fig. 2. 
 
TANNIN OR TANNIC ACID. 45 
 
 obtained, and to this is added a few drops of sulphuric acid. 
 The mixture is to be well agitated, then filtered, and to 
 the filtered liquid sulphuric acid, diluted with its own 
 weight of water, is added gradually, until the precipitate 
 formed, after standing for an hour, is found in the form of a 
 semi-fluid gelatinous mass. The liquid is then decanted 
 and carefully mixed with concentrated sulphuric acid so 
 long as a precipitate forms. The precipitate is then 
 washed with water strongly acidulated with sulphuric acid, 
 and is then pressed between the folds of bibulous (filtering) 
 paper. The precipitate is next dissolved in pure water, 
 and to the solution carbonate of lead, in very fine powder, is 
 added, and after agitation and maceration for some time, 
 until the sulpho-tannate is all decomposed, the mixture is 
 again filtered, and the liquid gently evaporated to dryness. 
 The residuum is finally powdered and digested in ether, 
 which is now allowed to evaporate spontaneously, and the 
 resulting powder is at once bottled to preserve it from 
 the air. 
 
 Bouillon-Legrange's Process. — By this method, an in- 
 fusion of nut-galls is precipitated by carbonate of am- 
 monia. The precipitate is afterwards washed with cold 
 water, and then digested repeatedly in fresh quantities of 
 alcohol at - 817. This process, however, does not yield 
 pure tannin. 
 
 Merat-Guillot's Process. — An infusion of nut-galls is 
 precipitated by lime water, and the precipitate treated with 
 dilute nitric or hydrochloric acid. Effervescence occurs, 
 and the liquor assumes a dark brown colour. After filtra- 
 tion, a bright black substance separates, which the inventor 
 assumes to be pure tannin, but according to Sir H. Davy 
 it is combined with vegetable extractive and a certain 
 portion of lime. 
 
 Dize^s Process. — This process consists in pouring con- 
 centrated sulphuric or hydrochloric acid into a concen- 
 trated infusion of nut-galls, when a white precipitate is 
 produced, which Proust believes to be a combination of 
 tannin with the acid employed. It is purified by washing 
 with cold water, then dissolved in warm water, and the 
 
46 LEATHER MANUFACTURE. 
 
 acid is saturated with, carbonate of potash. This process 
 does not produce pure tannin, but a substance in which 
 both gallic acid and extractive are present. 
 
 Deyeux's Process. — By this method, a strong infusion 
 of galls is precipitated with a concentrated solution of 
 carbonate of potash, when an abundant yellowish- white 
 precipitate is formed, which on drying yields a whitish 
 powder. The product, however, is not pure, as proved by 
 Davy and Tromsdorff, who found it to be a combination of 
 tannin, gallic acid, carbonate of potash, and lime. 
 
 Proust's Process — To an infusion of nut-galls is 
 added a solution of chloride of tin until the precipitate of 
 tannate of tin ceases to fall. A yellowish-white precipitate 
 is formed, which is afterwards washed and mixed with 
 cold water. A current of sulphuretted hydrogen gas is 
 then passed through the product, which, is next filtered 
 and then evaporated to dryness. Although a tolerably 
 pure product is obtained, the presence of gallic and 
 hydrochloric acids and extractive in small quantities have 
 been traced. 
 
 Serturner's Process. — By this process an alcoholic 
 inf vision of nut-galls is precipitated by warm carbonate of 
 potash. After decanting the liquid, the residue is washed 
 with alcohol, and then treated with sulphuric acid. This 
 is then evaporated, and the residue treated with alcohol. 
 The excess of sulphuric acid is precipitated by carbonate 
 of lime. After filtering, the filtrate is evaporated to 
 dryness, when tannin containing very little gallic acid is 
 the result. 
 
 Schering's Process. — This is called, by the patentee, 
 the "manufacture of improved tannic acid." The thick 
 extract, or solution of tannin, whether it be combined 
 with water, alcohol, or ether (!) is placed in a heated 
 chamber, the heat being maintained and regulated at a low 
 temperature, and the air excluded as far as possible. The 
 extract or solution is thus slowly evaporated, until it is 
 reduced to a thick pasty condition. It is then forced by 
 a pressing apparatus through a plate perforated with small 
 holes, from which it exudes in thin filaments, like thin 
 
TANNIN OR TANNIC ACID. 47 
 
 vermicelli threads ; these are wound, as they exude, on 
 suitable reels, or cylinders, or they may be collected in any 
 convenient manner. The threads so obtained, on cooling, 
 are very brittle, and will break up into golden, shining, 
 needle-like fragments, which can be readily collected, and 
 preserved in bottles. 
 
 Badvil and Lienders' Process. — The object of this 
 invention is to obtain "tanning material from the asphodel 
 plant," and is based upon the discovery that this plant 
 contains tannin which does not dissolve under the influence 
 of acids and fermentation, and which is not assimilable, 
 being diffused or mixed with a large proportion of water, 
 saccharine matter, and other substances. To render the 
 tannin " adaptable for leather dressing like the best 
 sumacs, it is necessary to eliminate the main portion of 
 the water and saccharine matter." For this purpose the 
 asphodel is washed, to free it from the earth which may 
 adhere to it ; it is then grated or crushed to break up the 
 cells, and the pulp thus obtained is then pressed. The 
 juice which flows from it is subjected to a complete fer- 
 mentation, to extract its alcohol. The pressed pulp, which 
 contains nearly all the tannin, is dried, preferably by 
 exposure to the sun, and finally reduced to a powder or 
 extract. " It can be used in this state for leather-dressing 
 purposes." 
 
 MM. Coez's Process. — The tanning matter or juices 
 being extracted by the usual processes, the decoctions are 
 placed in wooden vessels, in which they are intimately 
 subjected to the process of decoloration in the following 
 manner : — Oxalic acid is first added in the proportion of 
 one grain of acid to every 100 litres * of juice, the density 
 of which is unimportant, for the purpose of saturating the 
 lime which is contained in the water used in the process of 
 extraction, in proportions varying according to the quality 
 of the said water. After allowing a few minutes for the 
 oxalic acid to act, gelatinous alumina is introduced in the 
 proportion of about 250 grains per 100 litres of juice, and 
 
 * 1 litre is equal to 34 fluid ounces nearly, or about six ounces less than 
 an Imperial quart. 
 
4 8 LEATHER MANUFACTURE. 
 
 per degree of the density. The materials are now vigorously 
 agitated, and the mixture being immediately filtered, the 
 alumina remains upon the filter with the colouring matter. 
 The clear tannic liquid, from which the colouring matter 
 has thus been removed, is collected and evaporated in vacuo 
 by known means, and brought to a density of about 20° 
 Baume. The tannic extract obtained by this process is said 
 to be remarkably pure, is soluble, and readily assimilable 
 by hides or skins. 
 
 Kohlrausch's Process. — This process, which is also 
 applicable to the extraction of colouring matters from dye- 
 woods, consists in first reducing the wood or bark by cleav- 
 ing, breaking, sawing, &c, to small pieces about \ inch to 
 3 inches long, about the same width, and from -£$ to \ inch 
 thick. These pieces are placed in closed vessels of 
 copper or enamelled iron, and treated with water at about 
 20 to 75 0. (68° to 167° F.), under pressure, so as to ex- 
 tract tannic acid, &c, the different vessels forming a 
 "continuous working battery," and being connected with 
 each other by pipes, which may be heated if desired. If, 
 for instance, the " battery" consists of twelve vessels, pure 
 water, under pressure, is allowed to enter the first vessel, 
 where the process begins, and is continued until the den- 
 sities of the liquids inside and outside the bark-cells are 
 equalised. The liquid is afterwards allowed to pass from 
 the first into the second vessel, where the tannic acid 
 solution will become more concentrated. From the second 
 vessel the liquid passes into the third, and so on up to the 
 eleventh vessel, where the concentration of the liquid is 
 almost equal to that in the cells containing the raw 
 materials. During that time, pure water has been supplied 
 to the first vessel, by which its contents become exhausted 
 and may be discharged. Pure water is now admitted to 
 the second vessel, and the twelfth filled with raw material. 
 The extracted liquid is afterwards made to pass into the 
 twelfth vessel, the first filled with raw material, the second 
 discharged, and pure water allowed to flow into the third 
 vessel, and so on, in such a manner that the contents of ten 
 
TANNIN OR TANNIC ACID. 49 
 
 vessels are continuously subjected to dialysis* The 
 necessary temperature of the water may be maintained by 
 providing the connecting pipes with heaters of any suitable 
 construction. The extract obtained by this process may be 
 further concentrated in vacuum pans, or may be employed 
 directly for the manufacture of leather. 
 
 Properties of Tannic Acid. — This acid, as it exists in 
 different vegetables, varies in its chemical reactions, some- 
 times in a very marked degree. According to Gmelin, 
 the following plants contain the modification of tannin 
 which renders solutions of peroxide of iron (as the persul- 
 phate of iron for example) a deep blue : — Galls, the roots of 
 Lithrum salicaria, Geum urbanum, and rivale, Potentilla 
 argentea and anserina, Arctium lappa, Sanguisorba officinalis, 
 Poterium sanguisorba, Alchemilla vulgaris, Polygonum bistorta, 
 Iris pseudacorus, Nymphcea alba, the wood of the oak, and 
 many other trees, the bark of different species of oak, the 
 leaves of oak, Uva ursi, and many others, the twigs of the 
 black currant and sumac, the petals of pomegranate, Rosa 
 gallica and Pceonia officinalis. The tannin which gives a 
 green precipitate with persalts of iron is found in Catechu 
 and Kino, in the roots of the Tormentilla erecta, Potentilla 
 reptans, Rosa canina, Rheum rhaponticum, &c, in the diffe- 
 rent species of Cinchona bark, in Cinnamon, Cassia, and in 
 horse-chestnut bark; in the leaves of Salvia officinalis, 
 Lamium album, Glecoma hederacea, &c, in the varieties of 
 tea ; in the flowers of Tilia JEuropeea, Centaur ia cyanus, and 
 Arnica montana; in horse-chestnuts, date-stones, &c. 
 
 * In practical chemistry, the method of separating substances by " diffu- 
 sion," through a hoop covered with parchment paper, is called dialysis. 
 When a solution having a higher specific gravity is introduced into a 
 cylindrical glass vessel, and water then very cautiously poured into it in 
 such a way that the two layers of liquid remain unmoved, the substance 
 dissolved in the lower liquid will gradually pass into the supernatant 
 water, though the vessel may have been left undisturbed, and the tempera- 
 ture remain unchanged. The gradual passage of a dissolved substance 
 Irom its original solution into pure water takes place notwithstanding the 
 higher specific gravity of the substance which opposes this passage ; this 
 is called "diffusion of liquids," the investigation of which was due to 
 the late Professor Graham, of the Royal Mint, 
 
50 LEATHER MANUFACTURE. 
 
 According to the experiments of Berzelius and others, 
 the tannin in all plants is essentially the' same substance, 
 the different colours of the various precipitates with per- 
 salts of iron depending on the accidental presence of 
 impurities, and also on the nature of the salt of iron used. 
 But the more recent researches of Dr. Stenhouse favour 
 the conclusion that not only must the tannins of different 
 plants which produce different coloured precipitates in 
 the same solution of peroxide of iron be regarded as 
 distinct substances, but even that some of the varieties 
 of tannin which agree in their reaction upon salts of 
 iron, and in their general chemical habitudes, are by 
 no means identical.* Dr. Stenhouse availed himself of 
 a new test for tannin, which affords indications only with 
 the variety of tannin contained in galls, and with gallic 
 acid, which consists in the production of pyrogallic acid, 
 when the body to be tested is subjected to destructive 
 distillation: pyrogallic acid is disengaged as a crystalline 
 sublimate. 
 
 Farnell's Views. — This chemist observes : " Although 
 the astringent matter contained in several vegetables is 
 designated by the same name, tannin, or tannic acid, yet 
 all these bodies do not appear to be identical. The differ- 
 ences, however, which are perceptible in the properties of 
 most of the substances which are thus classed together 
 are small, and seemingly of no great importance in the 
 practical application of this vegetable principle. Other 
 vegetable matters exist, the properties of which amply 
 distinguish them from tannin. The most characteristic 
 properties of tannin are, astringency in taste, and the 
 power of being precipitated from its aqueous solution, 
 either of a bluish-black, or dark green colour, by a 
 solution of the peroxide of iron, and of a dirty white, or 
 
 * It is now generally recognised that although the numerous varieties 
 of tannin all possess the common property of precipitating gelatine, not 
 only do they differ greatly in their chemical reactions, hut the leather 
 produced from them is of very varied character — sometimes of very indiffe- 
 rent quality; and were it not for the custom of mixing certain tanning 
 materials with others of known excellence, it is douhtful whether some of 
 them would not he altogether abandoned. 
 
TANNIN OR TANNIC ACID. 5! 
 
 brown colour, by a solution of gelatine. The precipitate 
 produced in a solution of a persalt of iron, which is the 
 tannate of peroxide of iron, is the basis of common writing 
 ink. A solution of protomlphate of iron [copperas), per- 
 fectly free from all peroxide of iron, experiences no 
 immediate change on the addition of tannin; but the 
 mixture instantly becomes deep blue or black on exposure 
 to the air, through the absorption of oxygen, and forma- 
 tion of peroxide of iron. If cold aqueous solutions of 
 tannin and animal gelatine (glue, bone- size or isinglass), 
 are mixed in certain proportions, both of these bodies are 
 almost completely thrown down as a precipitate, known by 
 the name of tanno- gelatine, which generally contains about 
 half its weight of tannin. Sometimes, particularly when 
 heat is applied, or when the acid is in excess, the pre- 
 cipitate forms, on stirring, a very viscid and elastic mass, 
 somewhat resembling caoutchouc. In its chemical condi- 
 tion, tanno- gelatine is quite analogous to leather, and was 
 at one time, in fact, generally regarded as that substance 
 in a pure state. This cannot be the case, however, as 
 gelatine does not exist ready formed in the skin (according 
 to Berzelius) and tanno- gelatine, unlike leather, is slightly 
 soluble in water at the boiling point. The aqueous 
 solution becomes turbid on cooling, owing to the re-pre- 
 cipitation of the tanno-gelatine. This compound may 
 also be dissolved by an excess of a solution of gelatine, 
 but not by an excess of a cold solution of tannin. When 
 dried, it loses its viscidity and elasticity, and becomes 
 brittle and pulverulent." 
 
 Pure Tannic Acid is nearly colourless, inodorous, pre- 
 eminently astringent in taste, uncrystallisable, very soluble 
 in water, and less soluble in pure alcohol and ether. Its 
 aqueous solution reddens litmus, and decomposes the 
 alkaline carbonates, with effervescence. It combines 
 energetically with gelatine ; when, therefore, a piece of 
 skin or bladder is immersed, in its aqueous solution, the 
 tannic acid is entirely abstracted ; whereas, if gallic acid 
 were present, that acid remains dissolved in the water. 
 Tannic acid also furnishes an abundant white precipitate 
 
52 LEATHER MANUFACTURE. 
 
 in solutions of isinglass or glue. A concentrated aqueous 
 solution of tannic acid is precipitated by hydrochloric, 
 nitric, sulphuric, phosphoric, and arsenic acid ; but not 
 by oxalic, tartaric, lactic, acetic or citric acid. By the 
 prolonged action of acids and alkalies, tannic acid under- 
 goes various, and often complicated, changes, amongst 
 which its conversion into gallic acid is the most common. 
 — Branch. 
 
 By exposure to the air, a solution of tannic acid 
 gradually becomes turbid, and deposits a grey crystalline 
 powder, which is gallic acid. By contact with the air 
 oxygen is absorbed, and an equal volume of carbonic acid 
 is evolved ; only a portion of the tannic acid, however, is 
 thus decomposed, and is converted into gallic and ellagic 
 acids. It is the opinion of many, that the gallic acid 
 present in gall nuts is due to the absorption of oxygen 
 by the tannic acid, during the process of vegetation. 
 And to this end, possibly, the insect which inhabits the 
 gall nut during its development, may be the real active 
 agent. 
 
 Reactions of Tannic Acid. — The following reactions 
 of tannic acid are given by Abel and Bloxam* : — 
 
 Concentrated sulphuric acid, treated with (solid) tannic 
 acid, produces, immediately, a dark, purplish-black liquid, 
 but does not evolve carbonic oxide. 
 
 When heated on platinum, tannic acid burns, chars, and 
 emits a peculiar odour. 
 
 Alkalies, added to a solution of tannic acid, cause it to 
 absorb oxygen from the air, and to assume a brown colour. 
 
 Sesquichloride of iron produces a bluish-black precipi- 
 tate of tannate of sesquioxide of iron. 
 
 Dilute sulphuric (or hydrochloric) acid produces, in a 
 pretty concentrated solution of tannic acid, a white pre- 
 cipitate, which is an insoluble compound of the two 
 acids. 
 
 Tannin is precipitated from a tolerably strong solution 
 of the mineral acids, and these precipitates consist, according 
 
 * " Handbook of Chemistry." By F. A. Abel and C. L. Bloxam. 
 
TANNIN OR TANNIC ACID. 
 
 53 
 
 to Berzelius, of compounds of tannin with the acids respec- 
 tively. If the compound with sulphuric acid be boiled for a 
 few minutes in dilute sulphuric acid, the tannin becomes con- 
 verted into gallic acid, which is deposited in coloured 
 crystals on cooling. When the sulphuric acid employed 
 for this purpose is diluted with 7 or 8 times its bulk of 
 water, the crystals of gallic acid are colourless and nearly 
 pure. A similar change occurs according to Liebig where 
 the compound of tannin and sulphuric acid is boiled with 
 an excess of caustic alkali ; and the action of hydrochloric 
 acid on, tannin is quite the same as that of sulphuric acid. — 
 (Stenhouse.) In these cases of the conversion of tannin into 
 gallic acid, the action of the air is unnecessary. 
 
 Table of the Pekcentage of Tannin in Vegetable Substances. 
 
 Substance. 
 
 Per Centage 
 of Tannin. 
 
 Catechu, Bombay 55 - 
 
 „ „ light colour 26-3 
 
 „ Bengal 44-0 
 
 „ Peru, dark brown colour . . 46- 8 
 
 Ehatany root 42 - 6 
 
 „ 38-3 
 
 Kino — Tannin and Extractive 75*0 
 
 Butea Gum 73"2 
 
 Nut Galls, Aleppo 70-0 
 
 ,, Chinese 74-0 
 
 ,, Istrian 24-0 
 
 Old Oak, white inner hark 21*0 
 
 14-2 
 
 Young Oak, white inner bark 15 - 2 
 
 „ coloured, or middle bark 4 - 
 
 „ entire bark 6 - 
 
 ,, spring-cut bark 22 - 
 
 Oak, Kermes, bark of the root 8 - 9 
 
 „ 100 years old 8*5 
 
 „ young 13-8 
 
 ,, British 50 years old 8-9 
 
 „ Coppice 12 - 5 
 
 „ Irish 45 years old 9-50 
 
 „ Belgian 8-3 
 
 Terra Japonica, or Gambier 44'0 
 
 Avens root, Geum urbanum 41 - 
 
 Squill, bulb 24-0 
 
 Statice of South Carolina 124 
 
 Authority. 
 
 Davy. 
 Mulligan. 
 
 Peschier. 
 Gmelin. 
 A r auquelin. 
 E. Solly. 
 Crookes. 
 
 Rhodes. 
 
 Cadet de Gassincourt. 
 
 Davy. 
 
 Davy and Geiger. 
 
 Davy. 
 
 Davy and Geiger. 
 
 Muller. 
 
 >) 
 Mulligan and Downing. 
 
 Eisenbeck. 
 Tromsdorff. 
 Vogel. 
 Parrish. 
 
54 
 
 LEATHER MANUFACTURE. 
 
 Substance. Pe f r ,£entage 
 
 of Tannin. 
 
 Birch bark 1-6 . 
 
 14 . 
 
 Beech bark 2-0 . 
 
 Larch bark 1 -G . 
 
 Hazel bark 3-0 . 
 
 Chestnut, American rose 8 
 
 „ Carolina 6-0 
 
 ,, French 4-0 . 
 
 „ Spanish, white inner burk 1*3 
 „ ,, coloured or middle 
 
 bark 03 . 
 
 ,, ,, entire bark 0-5 
 
 ,, horse 2-0 
 
 Lombardy Poplar 3' 5 
 
 Blackthorn 3-3 . 
 
 Ash bark 33 
 
 Sassafras, bark of the root 58-0 
 
 Elm bark 2-9 . 
 
 Sumac, Sicily 24 - 
 
 ,, Malaga 16*4 
 
 „. 10-4 .. 
 
 , , Carolina 5-0 
 
 ,, A^irginia 27'0 
 
 „ 19-5 . 
 
 Willow, Leicester, Avhite inner bark 16 - 
 ,, ,, coloured or middle 
 
 bark 3-0 . 
 
 ,, ,, entire bark G - 8 
 
 „ 3-9 . 
 
 ,, ,, bark of the trunk 1-4 
 
 ,, weeping 16 - 
 
 Sycamore bark 16-0 
 
 ,, I"* • 
 
 Elder 2-3 . 
 
 Plum tree 1 - 6 
 
 Cherry tree 24-0 . , 
 
 ,, ,, Cornish 19-0 . 
 
 Tormentilroot 46 - 
 
 Comus sangninea of Canada 44*0 
 
 Alder bark 36-0 .. 
 
 Hemlock 139 .. 
 
 Dividivi 50-0 .. 
 
 49-2 
 
 Valonia 34-7 . . 
 
 Myrobalans 35 "0 
 
 Mimosa bark 17'8 .. 
 
 „ „ 31-1 .. 
 
 Apricot bark 32 - . . 
 
 Pomegranate 32*0 . , 
 
 Bohemian olive 14 - . . 
 
 Authority. 
 
 Davy. 
 
 Biggers. 
 
 Davy. 
 
 Cadet de Gassincourt. 
 
 De Fontenelle. 
 Davy. 
 
 De Fontenelle. 
 
 Davy. 
 
 Reinsch. 
 Davy 
 
 Crookes. 
 
 Davy. 
 
 Franck. 
 
 Cadet de Gassincourt. 
 
 Anon. 
 
 Muller. 
 
 Daw. 
 
 Mulligan and Downing. 
 
 Biggers. 
 
 Cadet de Gassincourt. 
 
 )> 
 Biggers. 
 Davy. 
 Biggers. 
 Cadet de Gassincourt. 
 
 Mulligan and Downing. 
 
 Crookes. 
 
 Muller. 
 
 Mulligan and Downing. 
 
 Crookes. 
 
 Mulligan and Downing. 
 
 Muller. 
 
 De Gassincourt. 
 
TANNIN OR TANNIC ACID. 55 
 
 Substance. ^T^Sf Authority. 
 
 Tan shrub, with myrtle leaves ..... . 13 - .. De Gassincourt. 
 
 Service tree, bare, June berry 18-0 .. ,, 
 
 Cloves 15-0 .. Davy. 
 
 Winter's bark 9-0 . . Henry. 
 
 The more recent methods of estimating tannin which 
 have been introduced since the foregoing determinations 
 were arrived at, render it advisable that the percentage 
 in this Table should be received with caution ; at the 
 same time it must be admitted (owing to the difference 
 which exists between tannins obtained from different 
 sources), that even the more modern determinations of 
 this substance are not wholly reliable. 
 
 Morfit's Observations. — 1. That tannin is never found 
 to any extent in the interior of the trunk of trees. 2. That 
 it does not exist in poisonous plants, nor in those with a 
 milky or viscid sap. 3. That its proportion is greater in 
 young than in old. plants. 4. That the tannin is converted 
 into bitter principle, as the plant increases in age. 5. That 
 it is most abundant in the cortical layers of the bark, and 
 is usually absent altogether in the epidermis. 6. That the 
 proportion of tannin in bark varies with the season, de- 
 creasing as the severity of the winter increases, and 7. 
 That the two extremes of the quantity are attained in winter 
 and spring. 
 
 Artificial Tannin. — According to Hatchett,* a substance 
 having some of the characteristics of tannin, and to which 
 the name artificial tannin has been given, may be formed 
 by digesting charcoal in dilute nitric acid for several days. 
 The charcoal is at length dissolved, and a reddish-brown 
 liquor is obtained, which yields, after careful evaporation, 
 a brown glossy substance, amounting to about 120 parts, 
 from 100 parts of charcoal. This artifical tannin differs 
 in one particular from natural tannin, namely, that it resists 
 the action of nitric acid, which decomposes all varieties of 
 natural tannin, though some are more capable of resisting 
 its action than others. Artificial tannin has a somewhat 
 
 * Philosophical Transactions, 1805-6. 
 
5& LEATHER MANUFACTURE. 
 
 bitter, astringent taste, is soluble in water, and forms an 
 insoluble precipitate in solutions of animal gelatine, con- 
 sisting, according to Hatchett, of 
 
 Artificial tannin 36 
 
 Gelatine 64 
 
 100 
 
 Hydrochloric and sulphuric acids produce brown precipi- 
 tates in solutions of artificial tannin, which are soluble in 
 hot water. A variety of artificial tannin may be formed by 
 digesting camphor and resins in sulphuric acid, until the 
 liquor becomes black, and on being poured into water 
 deposits a black powder, which being digested in alcohol 
 yields a brown matter, soluble in water, and which pro- 
 duces an insoluble precipitate with gelatine. 
 
CHAPTER V. 
 
 GALLIC A CID. 
 
 Gallic Acid. — Preparation of Gallic Acid from Galls. — Scheele's Method.- 
 Liebig's Method. — Graham's Method. — Pharmaceutical Methods.— 
 Properties of Gallic Acid. — Pyrogallic Acid. — Ellagic Acid. 
 
 Gallic Acid. — The frequency — nay almost constancy — 
 with which gallic acid is associated with the great astrin- 
 gent tanning principle, — tannic acid, — and the ready con- 
 version of the latter into the former, by the influence of 
 oxygen, renders it advisable that it should be considered 
 apart from its associates, more especially since this vege- 
 table acid often plays an important though an objection- 
 able part in the process of tanning. Gallic acid was 
 discovered by Scheele, and various methods of obtaining it 
 in a pure state were afterwards devised by Deyeux, 
 Braconnot, Liebig, and Dr. Stenhouse. The conversion of 
 tannic acid into gallic acid by the agency of oxygen was 
 first demonstrated by Pelouze ; and the existence of the 
 latter acid, independent of tannic acid, in several vegetables, 
 has been proved both by Dr. Stenhouse and Robiquet. 
 Since this acid, however, is almost always associated with 
 tannic acid in the various plants which yield these 
 substances, and moreover exists in much smaller propor- 
 tions than the tanning principle — often a mere trace — it 
 may not be unreasonable to infer that the existence of 
 gallic acid is due to the oxidation of the tannic acid 
 generated or secreted by plants, and that it is not formed 
 in nature as a separate and distinct substance. This view 
 is supported by the readiness with which tannic acid com- 
 bines with oxygen, when exposed to the air under certain 
 
58 LEATHER MANUFACTURE. 
 
 conditions, as we find when considering its mode of prepa- 
 ration from gall nuts. 
 
 Preparation of Gallic Acid from Galls. — The process 
 recommended by Dumas is as follows : A quantity of nut- 
 galls are reduced to powder, and this is next made into a 
 paste with water ; in this state, the mass is exposed to the 
 action of the air, in a warm situation, the temperature 
 being from 70° to 80° Fahr., for two or three months, more 
 water being added from time to time, to make up for that 
 which is lost by evaporation. At the end of the above 
 period, the mouldy, dark-coloured mass is strongly pressed 
 in a cloth, and the solid portion boiled in a considerable 
 quantity of water.* The solution is to be filtered tvhilst 
 hot, and on cooling, crystals of gallic acid will deposit at 
 the bottom of the vessel. These crystals are afterwards 
 to be well drained, and pressed between folds of white 
 blotting paper, and they are next to be purified, by boil- 
 ing them with about one- sixth of their weight of pre- 
 pared animal charcoal in eight parts of water. The solu- 
 tion is to be again filtered whilst hot, and the clear liquor 
 set aside to cool, when pure crystals of gallic acid will 
 be obtained, which must be well drained and dried over a 
 water-bath. 
 
 Scheele's Method. — A filtered decoction of galls is 
 exposed to the air for some months, in an open vessel ; 
 after a time it grows mouldy, and becomes covered with 
 a thick glutinous pellicle, or scum ; in two or three months 
 the sides of the vessel, and under portion of the pellicle, 
 are found to be covered with small yellow crystals of gallic 
 acid, which may be purified as above. 
 
 Liebig's Method. — To a strong aqueous solution of 
 tannic acid, sulphuric acid is added so long as a precipitate 
 falls ; the powder is collected, washed and dissolved by 
 heat, in dilute sulphuric acid; the solution, after boiling for 
 a few minutes, and then being allowed to cool, deposits 
 abundant crystals of gallic acid. 
 
 Graham's Method. — A strong infusion or decoction of 
 
 * Gallic acid is soluble in 100 parts of cold water, and in 3 parts of 
 boiling water. 
 
GALLIC ACID. 59 
 
 galls is precipitated with sulphuric acid in the cold ; the 
 resulting thick mass is mixed with cold dilute sulphuric 
 acid, and the liquid pressed out. The " marc " is next 
 treated with sulphuric acid, diluted with twice its weight 
 of water, and after boiling the mixture for some minutes, 
 the whole is set aside to cool ; the resulting crystals are 
 purified with animal charcoal, as before. 
 
 Pharmaceutical Methods — The Dublin Pharmacopoeia 
 gives two methods of preparing gallic acid, one of which 
 is based upon the process of Dumas, or Scheele, and 
 the other on that of Graham or Liebig. 1. Galls, in 
 coarse powder, 1 lb. ; make into a stiff paste with water, 
 and place in a porcelain dish, and expose in the moistened 
 condition for six weeks. The solution of the first crop of 
 crystals is made in 10 fluid ounces of boiling icater, and 
 then filtered. When the nitrate (the filtered liquor) has 
 cooled down to 80° Fahr., it is to be poured off from the 
 crystals which have formed, and the crystals are to be 
 washed with ice-cold icater, 3 fluid ounces, and then drained 
 and dried — first on blotting paper, and finally by steam or 
 water heat. By boiling the undissolved portion of the 
 galls with 45 fluid ounces of fresh water, more crystals are 
 obtained. 2. One pound of powdered nut-galls are steeped 
 for 24 hours in 1 pint of water, and after being placed in 
 a porcelain dis23lacement apparatus, are treated with one 
 and a half pint of water, added in successive portions ; 5 
 fluid ounces of oil of vitriol, diluted with an equal bulk 
 of water and allowed to cool, is then added to the perco- 
 lated infusion, and when thoroughly mixed, the liquid is 
 filtered from the precipitate which forms. Oil of vitriol 
 5 fluid ounces diluted with an equal bulk of water as 
 before, is now added to the filtrate ; the precipitates, 
 enveloped in calico, are submitted to powerful pressure, 
 and subsequently dissolved in a solution composed of oil 
 of vitriol 16 fluid ounces, and water 56 fluid ounces. The 
 solution is then boiled for 20 minutes, and set aside for a 
 week, at the end of which time the deposit which forms is 
 dissolved in three times its weight of boiling water, and the 
 solution treated as before. 
 
6o LEATHER MANUFACTURE. 
 
 Properties of Gallic Acid. — Pure gallic acid assumes 
 
 the form of white or nearly colourless feathery crystals of 
 a beautiful silky lustre ; the commercial acid, however, is 
 usually of a pale yellow colour ; it is soluble in alcohol, and 
 also, sparingly, in ether ; its solution in water undergoes 
 decomposition when exposed to the air. When strongly 
 heated, gallic acid is converted into meta- gallic acid, or 
 into pyrogallic acid, according to the way in which the 
 heat is applied. Gallic acid is distinguished from tannic 
 acid by not precipitating gelatine from its solution,* and 
 by not affecting the proto-salts of iron (as proto- sulphate of 
 iron, for example), and by giving a deep bluish-black pre- 
 cipitate with sesqui or per salts of iron (as persulphate of 
 iron) which disappears when the liquor is heated. It is 
 distinguished from pyrogallic acid by its inferior solubility 
 in water. If, in a mixed solution of gallic acid and tannic 
 acid, a piece of depilated skin be immersed for some time, 
 the whole of the tannin will be absorbed by the skin, leav- 
 ing the unaltered gallic acid in solution. 
 
 Gallic acid is useless for tanning purposes, therefore it is 
 of considerable importance to prevent, as far as possible, 
 the conversion of the tannin contained in the tanning liquors 
 into gallic acid — a change that is more likely to occur 
 when ooze or infusion of the astringent matter is used, 
 than when ground bark and water only is employed, as in 
 the old tanning process. When tanning solutions undergo 
 decomposition, a considerable percentage of tannin is con- 
 verted into gallic acid and other modifications of tannic 
 acid, by which a positive loss of tanning power is sus- 
 tained. The tannin from galls and sumac is very liable 
 to undergo this change, in consequence, probably, of the 
 insoluble matters acting as a ferment, and thereby pro- 
 moting the conversion of tannin into gallic acid.f This 
 subject will be further considered when treating of gallic 
 fermentation. 
 
 Although gallic acid possesses no tanning property, its 
 
 * Pure gallic acid will not throw down a precipitate from a solution of 
 isinglass. 
 
 t Parnell thinks that the malic acid existing in sumac leaves is the 
 cause of the rapid fermentation of sumac liquors. 
 
GALLIC ACID. 61 
 
 existence in spent or exhausted tan liquors is sometimes 
 taken advantage of to swell the hides after they have been 
 limed in the usual way, instead of employing dilute 
 sulphuric acid, by which the absorption of the tannin is 
 promoted. 
 
 Besides being present ready formed in galls and sumac, 
 gallic acid occurs in some other vegetables ; it is said to be 
 found in the seeds of the mango-tree, in divi divi, valonia, 
 black and green teas and myrabolams. 
 
 Pyrogallic Acid. — When gallic acid is subjected to dry 
 disfflJation, at a temperature between 410° and 420° Fahr., 
 a white crystalline substance distils over, which is pyrogallic 
 acid. Its preparation, according to the method suggested 
 by Dr. Stenhouse, is as follows : — Finely powdered galls 
 are treated with successive portions of cold water till ex- 
 hausted, and the infusions carefully evaporated to dryness, 
 when they leave a spongy, deliquescent (that is, capable of 
 absorbing the moisture from the air) mass, which is to be pul- 
 verised and spread equally over the bottom of a cast-iron pan, 
 3 or 4 inches deep, and about a foot in diameter, the top of 
 which is covered with a diaphragm of bibulous paper (filter- 
 ing paper) pasted round its rim, pierced with pin holes, and 
 surmounted by a paper cap 12 to 18 inches high. The pan 
 is then cautiously heated for 10 or 12 hours, over an oil- 
 bath, so as to preserve its temperature as nearly as possible 
 at about 400° Fahr.* The crystals of sublimed pyrogallic 
 acid collect in the cap, and the other products are chiefly 
 absorbed and retained by the paper diaphragm. 
 
 Pyrogallic acid is white, crystalline, without odour, and 
 
 of a bitter taste. When pure it does not redden litmus 
 
 paper ; it is very soluble in water, ether and alcohol. This 
 
 acid has been much used in photography, its application 
 
 having been first suggested by the author's late friend, Mr. 
 
 Frederick Scott Archer — the inventor of the well-known 
 
 " collodion process." 
 
 * If the heat of the bath be rapidly increased, and the oil allowed to 
 boil, carbonic acid will be given off, instead of the crystalline sublimate, 
 water will distil over, and a brilliant black mass left behind, wbich has 
 been called, by Pelouze, Metagallic acid, a tasteless, insoluble substance, 
 resembling carbon, but nevertheless a true acid. 
 
62 LEATHER MANUFACTURE. 
 
 Ellagic Acid. — This name, which is derived from the 
 word galle, read backwards, was given by Braconnot to a 
 substance formed along with gallic acid when moistened 
 galls are exposed for some time to the air. Its existence 
 was first noticed by Chevreul. According to Grischow, 
 ellagic acid exists in the root of Tormentilla erecta. Being 
 insoluble in boiling water, it remains after the gallic acid 
 has been extracted, and may be dissolved out of the residue 
 by a very weak solution of potash. If dilute hydrochloric 
 acid be now added to this solution, a brownish precipitate 
 is formed, which is ellagic acid, a tasteless substance almost 
 insoluble in water, alcohol, and ether. It slightly reddens 
 litmus paper. The bloom which appears upon the surface 
 of tanned skins or hides, is ellagic acid. 
 
 Besides the above acids, there are numerous other deri- 
 vatives of tannin, which, however interesting in themselves, 
 are of no importance to the tanner, and therefore need not 
 be dwelt upon in these pages. 
 
CHAPTER VI. 
 GALLIC FERMENTATION. 
 
 Checking or Preventing Gallic Fermentation. 
 
 It being an established fact that tannic acid, under the 
 influence of moisture and atmospheric air, becomes con- 
 verted into gallic acid, it will readily be understood that 
 tan liquors, which are constantly exposed to the air, will 
 naturally be susceptible of this change, and, as a conse- 
 quence, a portion of their active princij)le (tannin) must 
 in course of time suffer decomposition. Apart from this, 
 however, & fermentative process takes place in the liquors, 
 by which a considerable proportion of the active principle 
 is converted into gallic acid ; this is denominated gallic 
 fermentation, and has been a constant source of trouble and 
 loss to the tanner. According to the researches of Larocque, 
 the peculiar ferment of nut galls which operates the 
 change, also converts sugar into alcohol and carbonic acid, 
 in the same way that yeast does, whilst beer yeast, mus- 
 cular flesh, and caseous matter (the solid matter of milk) 
 change tannin into gallic acid. Hence gallic and vinous 
 fermentation are considered to be nearly identical. 
 
 According to Wackenroder and Larocque, it appears 
 that the formation of gallic acid from tannin is consider- 
 ably expedited by the contact of the insoluble vegetable 
 matters which remain after the extraction of the tannin, 
 at least in the case of nut-galls, and probably in that of 
 all vegetable matters containing tannin susceptible of this 
 change by exposure to the air. Larocque found that all 
 the tannin contained in an aqueous solution of that sub- 
 stance, to which was added the residue of the preparation 
 
64 LEATHER MANUFACTURE. 
 
 of tannin from gall nuts by means of ether, became entirely 
 converted into gallic acid, although in a closed vessel ; 
 while a strong solution of pure tannin, freely exposed to 
 the air during the same length of time, contained nearly 
 the whole of the tannin unaltered. It is therefore con- 
 cluded that the insoluble residue of the nut-galls contains a 
 substance capable of acting on tannin as a ferment, and 
 that the change of tannin into gallic acid in such cases is 
 a species of fermentation. This is rendered still more 
 probable, from the circumstance that the vinous fermenta- 
 tion may be excited in grape sugar by powdered nut-galls 
 which have been digested in ether; and also that contact 
 with yeast, blood and albumen, produced the same effect 
 on tannin as contact with the residue of nut-galls, though 
 not with the same rapidity as the latter. The gallic acid 
 formed from the tannin of nut-galls, through the agency 
 of yeast, is mixed with a quantity of a brown bitter sub- 
 stance. 
 
 Is it not probable that while tannin exists in its natural 
 proportion in the tanning infusions, that it prevents the 
 fermentative decomposition to which the vegetable matters 
 would be susceptible when free from it, and that when, in 
 the ordinary process of tanning, the skins have removed, 
 by absorption, a considerable portion of the astringent 
 principle, the vegetable matter then undergoes decompo- 
 sition, or incipient fermentation, which, when once set in, 
 proceeds with increasing activity ? We are induced to 
 offer this suggestion because we believe that, while tannin 
 exists in due proportions in solution with the vegetable 
 matters derived from the plant, gallic fermentation does 
 not take place, but that when this proportion becomes 
 reduced — either by the action of the oxygen of the air, 
 or by absorption of tannin by the hides — fermentation 
 supervenes. 
 
 Checking or Preventing Gallic Fermentation. — 
 Labaroque has observed that the fermentative decompo- 
 sition of tannin may be prevented or checked by all the 
 antiseptic substances which arrest vinous fermentation, 
 such as aromatic substances and volatile oils, and soluble 
 
GALLIC FERMENTATION. 65 
 
 salts of mercury. Corrosive sublimate is said to prevent 
 the decomposition most effectually. According to the 
 same authority, the presence of atmospheric air is not 
 essential to the conversion of tannin into gallic acid, and 
 no appreciable quantity of gas is liberated during the 
 decomposition. 
 
 It has been proved that dilute sulphuric and hydro- 
 chloric acids speedily convert tannin into gallic acid 
 without contact of the air, when the mixture is exposed 
 to a moderate heat; and it has been demonstrated by 
 M. Afftoine that the decomposition of tannin, when 
 exposed to the air, is not at all accelerated, but rather 
 retarded, by the presence of a very minute quantity of 
 either of the above acids, provided the mixtures be kept at 
 the ordinary temperature. Pyroligneous acid possesses 
 the property of retarding the decomposition of tannin to 
 a very considerable extent, probably owing in a great 
 measure to the presence of empyreumatic bodies. On 
 the contrary, tartaric and malic acids, and vegetable acids 
 in general, accelerate the decomposition of tannin. The 
 rapidity with which sumac ferments may be referred in a 
 great degree to the presence of a considerable quantity 
 of malic acid in the leaves, according to some analyses. — 
 Parnell. 
 
 " From the preceding observations," saj^s the same 
 author, "may be inferred some of those conditions which 
 the tanner should endeavour to avoid or obtain, in order 
 to retard, as much as possible, the conversion of the tan- 
 ning principle into gallic acid, the latter being incapable 
 of combining with gelatinous tissue. Though the obser- 
 vations refer particularly to the tannin of gall nuts, which 
 is believed to be the same kind as that of sumac, yet 
 there is every reason to believe that they are applicable to 
 all vegetable substances which contain a variety of tannin, 
 not even excepting those the tannin of which is not con- 
 vertible into gallic acid ; for all kinds of tannin are sub- 
 ject to a fermentative decomposition, though the different 
 varieties may afford very different products, and, in all 
 probability, the same agents which possess the power of 
 
 F 
 
66 LEATHER MANUFACTURE. 
 
 restraining the fermentation of one variety would that of 
 another. An idea prevails amongst some tanners, how- 
 ever, that gallic acid exerts some beneficial action or other 
 in the process of tanning. This we certainly admit, pro- 
 vided the ordinary process is followed ; but undoubtedly 
 it is at the expense of a far more valuable and important 
 agent." 
 
 As to the part which gallic acid performs in the process 
 of tanning, since it is well known that it does not enter 
 into the substance of the skin, so as to form a constituent 
 of the leather, we may take it that its functions are of a 
 secondary character, merely aiding the absorption of the 
 tannin by swelling the pores of the skin, in the same way, 
 and to about the same extent, as dilute sulphuric acid. 
 If, however, the hides, after liming, have been raised by 
 the dilute mineral acid, it is difficult to conceive that 
 gallic acid performs any useful part in the operation of 
 tanning. If it could be shown that this acid assisted in 
 promoting the combination of vegetable extractive with 
 the substance of the skin, its importance as a constituent 
 of tanning infusions would be readily understood and 
 appreciated, and indeed it may be possible that in some 
 way not yet understood such is really the case. 
 
 Knowing that the oxygen of the atmosphere readily 
 converts the tannin of tanning infusions into gallic acid,* 
 may we not conclude that the process of handling favours 
 this chemical change ? The skins, while supersaturated 
 with tan liquor, are repeatedly exposed to the air, and 
 the liquor which attaches to them, as also that which flows 
 from them, after removal from the pits, necessarily ex- 
 poses a very large superficial surface to the action of the 
 air ; and it is not reasonable to suppose that under these 
 conditions a considerable portion of the tannin is trans- 
 formed into gallic acid ? If this be so, is not the process 
 of handling, as at present conducted, a mistake ? 
 
 Is not the system of suspension preferable ? Against 
 this method it has been urged that after a while the tan- 
 ning liquor, by remaining stagnant, suffers decomposition ; 
 * Especially when other organic matters are present. 
 
GALLIC FERMENTATION. 67 
 
 tliis, however, could be checked by keeping the liquor in 
 gentle motion by means of a suitable agitator, by which 
 the skins would be constantly exposed to fresh surfaces of 
 the liquor, while at the same time it would be kept in an 
 uniform condition until the whole of the tannin had 
 become absorbed, when the spent liquor would be run off 
 and replaced by fresh, in the usual way. The arrange- 
 ments described in another place, would appear to be a 
 feasible plan of treating skins in tan-liquor, and would, 
 we should say, render the process of handling to a great 
 extent unnecessary. 
 
 Carbolic acid has been frequently used, with good 
 effect, to check gallic fermentation ; pyroligneous acid 
 (wood vinegar) has also, as we have said, been employed, 
 but since its action is believed to be chiefly due to the 
 empyreumatic matter Avith which it is impregnated, pro- 
 bably commercial wood spirit (pyroxilic spirit), in small 
 quantities, would have a similar, if not a more powerful, 
 effect, since it contains a still larger quantity of empy- 
 reumatic matter. We are not aware if this substance has 
 been tried, but are disposed to think that a few experi- 
 ments might be made with advantage. Being soluble in 
 water, in all proportions, there would be no difficulty in 
 applying the wood spirit ; the quantity used must be 
 small, however, otherwise it will impart its natural, but 
 not disagreeable, odour to the leather ; this, however, 
 would probably disappear during the treatment of the 
 skins in the layers. 
 
CHAPTER VII. 
 
 TANNING MATERIALS. 
 
 Sources of Tannin. — Barks. — Oak Bark. — Barking of Trees. — Nut Galls. 
 — Tanning Extracts. — Catechu.— Kino. — Gambier or Terra Japonica. 
 — Hemlock Extract. — Chestnut Extract. — Oakwood Extract. — Larch 
 Extract. — Quebracho Extract. — Sumac. — Bhatany Boot. — Mangrove 
 Extract. — Myrobalans. — Valonia. — Divi divi. — Mimosa Bark. — List 
 of Tanning Materials. — Miscellaneous Tanning Materials. 
 
 Sources of Tannin. — Since the period when Lewis, 
 Deyeux, Seguin, Davy and others investigated the princi- 
 ples of tanning, the vegetable kingdom has been industri- 
 ously explored, and a vast number of plants examined to 
 determine the presence of tannic acid and its proportion 
 in the various parts of trees, shrubs, and herbs. These 
 researches have not only increased our knowledge as to the 
 wide diffusion of the important proximate principle, 
 tannin, but have also developed new sources from which 
 it can be obtained with advantage for the purposes of the 
 tanner. 
 
 The sources of tannin are classified under the following 
 heads, namely — 
 
 Barks, as of the oak, birch, mangrove, mimosa, &c. 
 
 Boots, as of rhatany, male fern, tormentil, &c. 
 
 Leaves, as of sumac, pomegranate, tea, &c. 
 
 Excrescences, or gall nuts. 
 
 Extracts, as catechu, gambier, &c. 
 
 Flowers and Fruits. 
 
 Seed pods. 
 
 Barks. — One of the most important sources of tannin is 
 the bark of certain trees, but more especially of the various 
 species of oak, willow, hemlock and chestnut. The bark 
 
TANNING MATERIALS. 69 
 
 is the rind or exterior covering of vegetables, correspond- 
 ing to the skin of animals. It consists of the cuticle, or 
 epidermis, the parenchyma, a cellular structure containing 
 colouring matter, &c, and liber* the inner or true bark. 
 This last is formed of woody fibre in great quantity, inter- 
 mixed with cellular tissue. At the commencement of the 
 annual growth of a tree, the bark separates spontaneously 
 from the wood, in order to make room for the new matter 
 forming beneath. It thus increases by yearly layers, and 
 gradually perishes on the outside, owing to the distension 
 from thg growth of the inner portion. Its physiological 
 uses are numerous and important ; it is the depository of 
 many of the secretions of plants, and it acts as a living 
 filter, separating secretions from each other, and allowing 
 a part of them to pass off horizontally through the medul- 
 lary processes on their way to the centre of the tree. But 
 the principal offices of the true bark appear to be to act as 
 a protection to the tender wood, and as a channel for the 
 sap in its descent from the leaves. This latter function 
 directs attention to that period of the year when the sap is 
 in most vigorous circulation — the spring, at which time 
 the active principles deposited in the cells of the bark are 
 most abundant. For example, oak bark collected in 
 spring contains four times as much astringent matter as 
 that collected in winter. — Coolcy. With few exceptions, 
 the bark is more easily removed from a tree in spring than 
 at any other period of the year. When a tree, or one of 
 its branches, is cut across, the bark is easily distinguished 
 from the interior layers by its colour ; and if we examine 
 the bark we find that its three layers are perfectly distinct, 
 and may be readily separated. 
 
 Oak Bark. — This most important of all tanning 
 materials has always been employed by British tanners 
 in preference to any other ; and although large quantities 
 of tanning materials from other sources are consumed in 
 Great Britain, their employment is rather from necessity — 
 owing to the weakness in tannin of oak bark — than from 
 
 * So called from liber, a book, because in the early ages the inner bark 
 was stripped off in layers, and formed into leaves, for writing upon. 
 
70 LEATHER MANUFACTURE. 
 
 choice. Oak bark yields its tannin under the most 
 favourable conditions for the gradual combination of the 
 astringent matter with the tissue of the skin, and at the 
 same time it parts with its extractive matter in such a 
 way that by slow degrees it enters into the substance of 
 the skin, and doubtless plays an important part in the 
 formation of sound and durable leather. 
 
 There are several varieties of oak, the barks of which are 
 famous for their richness in tannin, amongst which may 
 be named Quercus robur, Q. coccifera, Q. suber, European 
 varieties ; Q.falcata, Q. rubra, Q. tinctoria, &c, indigenous 
 to America. " The bark of Quercus robur — which term is 
 applied to designate a group of closely -allied species or 
 varieties, and of which the Q. peclunculata and Q. sessili- 
 flora form the two principal — is generally preferred by 
 the tanner, with the exception of Norway, the North of 
 Russia, and some districts in France. In Norway the 
 birch and willow are resorted to, and in Russia and France, 
 the bark of other species of oak, the Quercus glomerata and 
 Q. coccifera are occasionally substituted. The latter 
 varietj r , known also as the kermes oak, is a tortuous, 
 branching shrub, inhabiting the south of France, Portugal 
 and Spain. It grows to the height of three or four feet, 
 in close clumps, the roots interlacing one another, so that 
 the soil, which might otherwise be washed away by the 
 heavy rains, is retained. The bark of the root of this 
 shrub, which is sometimes called coppice oak, is of a 
 yellowish-brown hue, and very rich in tannin. It is 
 much in request in France for tanning sole leather of a 
 superior quality." — Muspratt. 
 
 The common English oak (Q. robur, Linnaeus) is by 
 some botanists named Q. peduncula.ta ; its acorns are 
 borne on long peduncles (stems supporting the fruit), 
 and is thus distinguished from Q. sessiliflora, which has 
 its acorns clustered upon a very short stalk, or sessile 
 (sitting), with leaves on elongated stalks. When deprived 
 of its epidermis, it is of a light brown colour externally ; 
 it has a slight odour, but the taste is bitter and roughly 
 astringent. Its properties are readily extracted by water 
 
TANNING MATERIALS. 71 
 
 and by proof spirit. Its constituents are tannin (about 
 15 per cent.), gallic acid, uncrystallisable sugar, tannates 
 of lime, magnesia, potash, &c. The inner part of the 
 bark, as before observed, contains the largest proportion 
 of tannin. 
 
 Barking of Trees. — Since observation has proved that 
 tannin exists in the bark of trees during spring time to 
 a much greater extent than at any other period of the 
 year, it must be evident that great care is necessary to 
 obtain the bark when it is in a condition most favourable 
 to the requirements of the tanner. Until the subject had 
 been thoroughly investigated — and in this the careful 
 researches of Davy and other scientific men have been of 
 immense service to the tanner — the rind of old oaks was 
 deemed of more value for tanning purposes than the pro- 
 duct from younger wood. Experience, and a more in- 
 timate knowledge of the chemistry of the subject, have 
 shown that not only does the bark of younger wood yield 
 more tannin than that from older trees, but the leather 
 prepared with it is softer and whiter. " Doubtless the 
 best age at which the trees should be barked is from 
 eighteen to twenty-five or thirty years ; but owing to the 
 importance of the timber for building and other purposes, 
 rarely are trees of this age felled in England or European 
 countries. In France, however, they harvest the bark of 
 the oak at this age, but the wood is not turned to further 
 use, excepting for the manufacture of charcoal, owing to 
 this variety not being adapted for the builder. In France, 
 too, the advantage may be gained of collecting the bark in 
 the spring, at a time when the sap is in full flow, and 
 when there is most tannin contained in it ; but in other 
 countries, where the bark of the tree constitutes only an 
 inferior secondary product, compared with the wood, this 
 season is not chosen, in consequence of the timber being 
 cut when the sap is in active circulation, and thus less 
 liable to decay." — Muspratt. 
 
 The period for debarking the trees in England, Holland 
 and America, is about June, but this depends upon the 
 mildness of the winter and spring. Barking is performed 
 
72 LEATHER MANUFACTURE. 
 
 by cutting two circular bands round the trunk, about two 
 or three feet apart; a longitudinal strip is then cut from 
 one band to the other and the bark loosened at the upper 
 band and stripped off by means of peeling irons, the bark 
 being beaten when necessaiy. The strips, when removed, 
 are spread out to dry, in beds, in a shady situation, and they 
 are turned over occasionally to prevent the bark from 
 heating. 
 
 The harvesting of the bark requires to be conducted 
 with great care, otherwise not only will the bark suffer 
 loss of tannin, but also produce an inferior leather in the 
 tan pits. Muspratt observes, " For the most part, or, 
 indeed, in all cases, the bark should rest on hurdles 
 elevated more or less from the ground, in an inclined 
 state, and the fragments ought never to be heaped 
 together more than twelve to eighteen inches in thickness. 
 Provision ought to be made to protect the bark from the 
 rain, and the whole should be turned at least once a week 
 till quite dry. After this it is usually stacked in rect- 
 angular heaps, and protected by thatch, if not by a roof, 
 from rain and wet." 
 
 In the year 1897 it was stated that about 40,000 tons 
 of oak bark was annually imported into England from 
 Germany, the Netherlands, and ports in the Mediterranean, 
 but there is no means of ascertaining how much English 
 oak bark is obtained. 
 
 Davy gives the following quantities of tannin contained 
 in oak bark : — 
 
 480 lbs. of entire bark, of a middle sized oak, cut in 
 
 spring 29 lbs. 
 
 ,, coppice oak 32 „ 
 
 ., oak cut in autumn 21 „ 
 
 "White cortical layers 72 „ 
 
 According to Braconnot, oak bark contains, besides tannic 
 acid, tannates of the earths, gallic acid, pectin, and lignin. 
 
 The proportions of tannin in Elm, Willow, and other 
 barks, &c, are given in the foregoing table. 
 
 Cork-tree bark is obtained from Quercus suber, a species 
 of oak growing in Spain, Tuscany, and the islands of 
 
TANNING MATERIALS. 73 
 
 Corsica and Sardinia, and on the northern coasts of 
 Africa. The outer layer or bark of the tree constitutes 
 what is known as cork, while the inner layer, which is of 
 considerable thickness, is procured, from its richness in 
 tannin (about 12 per cent.), as a tanning material, the 
 greater portion of which is employed by the tanners of 
 Ireland. 
 
 Nut-galls. — These remarkable excrescences, which con- 
 tain a large percentage of tannin, and also gallic acid, are 
 imported largely into England from Smyrna, being the 
 produce of Asia Minor ; also from Aleppo, the produce of 
 the vicinity of Mosul in Kurdistan, a province of Persia. 
 They are also imported from Bombay. Besides the names 
 applied from the places whence they are obtained, the 
 Levant galls are distinguished by their physical character- 
 istics, being called Blue or White galls. The Blue galls 
 vary in size, and are of a bluish-grey colour. They are 
 gathered before the insect [Cynips] becomes fully de- 
 veloped, or worked its way out of the nut. Some of these 
 are larger, and are called Green galls, from being of a 
 greenish colour. They exhibit on their otherwise smooth 
 surface, a number of bluntly-pointed tubercles, which 
 would appear to be the apices of leaves stimulated into 
 unnatural growth. The best galls are heavy, hard, and 
 shining, and break with a short flinty fracture. White 
 galls are so called from being of a lighter colour than the 
 others, but still of a greyish or yellowish hue. They are 
 distinguished by being perforated with a small round 
 hole, by which the insect had escaped. They are usually 
 less heavy than the others, have a larger internal cavity, 
 and are not so astringent. A third variety, called Large 
 Mecca galls, are sometimes imported from Bussorah ; they 
 are called Dead Sea Apples, and Mala insana. They are 
 identical with some specimens brought by the Hon. B. 
 Curzon from the Holy Land in 1847. They are spherical 
 in shape, and surrounded about the centre by a circle of 
 horned protuberances. They are astringent like other 
 galls, and, when fresh, are said to be purple and shining. 
 They are thought to be the produce of a peculiar variety 
 
74 LEATHER MANUFACTURE. 
 
 of Quercus infectoria, which grows on the mountains near 
 the Dead Sea. Peculiar galls of an irregular shape have 
 occasionally been imported from China, where they are 
 known by the name of Woo-pei-tzee. They are very 
 astringent, and are supposed by Dr. Schenk to be formed 
 by the puncture of the leaves of the Rhus semialata (Tere- 
 binthacas) by a peculiar species of Aphis. 
 
 Tanning Extracts. — Catechu. — This important tan- 
 ning material is also known in commerce by the names 
 Cashew, Cutch, Gambler, and Terra Japonica (Japan earth). 
 Catechu is properly an extract prepared from the wood of 
 Acacia Catechu, but the term is now applied to other 
 extracts similar in appearance and properties. The leaves 
 of the Uncaria gambir yield an extract which is known in 
 commerce as Terra Japonica, Gambir, or Gambler, which 
 is prepared in square pieces or blocks (cube gambier). 
 The acacias, however, are most famous for the secretion 
 of astringent matter in the wood, bark, and legumes (seed 
 vessels) of various species, from which the catechus of 
 commerce are obtained. Catechu is generally in square or 
 roundish pieces or balls, varying in colour from a pale 
 whitish or light reddish brown, to a dark brown colour ; it 
 is either earthy in texture, lamellated, or presents a smooth 
 shining fracture. Some kinds are more friable (easily 
 crumbled) than others, and all are without smell. The 
 taste is powerfully bitter and astringent, and leaves a sweet 
 after-taste. The pieces are generally of a darker colour 
 externally than they are inside. Some kinds are covered 
 with rice husks, others are enveloped in leaves. The pale 
 variety is usually distinguished from the dark coloured, 
 and is said to be imported from Calcutta, but we have 
 obtained both kinds in the bazaars there, the pale being 
 imported from the upper provinces, and the dark from 
 Pegu and Singapore. The dark brown catechus are ob- 
 tained from Bombay, but both kinds may no doubt be 
 prepared from the same tree, as a greater degree of heat, 
 or longer continued heat, and greater exposure to light, is 
 said to produce the dark colour. The dark are heavier, 
 more dense in texture, and have a resinous fracture. The 
 
TANNING MATERIALS. 75 
 
 largest portion of good catechu is taken up by water, 
 especially when boiling, the infusion being of a light red 
 or reddish-brown colour, according to strength : it reddens 
 litmus, and is strongly astringent in taste. It yields a 
 precipitate with the salts of ammonia, also with acetate of 
 lead, and one of a blackish-green colour with the salts of 
 the sesquioxide of iron. — Dr. Royle. 
 
 Sir Humphry Davy, in analysing the dark and pale 
 catechu, or those of Bombay and Bengal, obtained from- — 
 
 
 
 
 
 Insoluble 
 
 
 Of Tannin. 
 
 Extractive. 
 
 Mucilage. 
 
 Residuum. 
 
 Dark catechu 
 
 .. 109 
 
 68 
 
 13 
 
 10 = 200 
 
 Pale „ 
 
 .. 97 
 
 .. 73 
 
 16 
 
 14 = 200 
 
 The principle which Davy termed extractive has since 
 been named CatecMne, or Catechaic acid. This is most 
 easily obtained by treating gambier with cold water ; the 
 tannin being dissolved, the insoluble residue is impure 
 catechine, which may be purified by dissolving in alcohol 
 and subsequent crystallisation, when it has the appearance 
 of a white powder, but is in the form of silky needles, of a 
 somewhat sweetish taste, producing a green colour with 
 salts of iron. M. Soubeiran, who made a series of experi- 
 ments with catechu, came to the conclusion that Pegu 
 catechu is the most astringent of all the vegetable astrin- 
 gents ; next to this, in astringency, is Jamaica kino ; next 
 Amboyna kino ; fourth on the list is Indian catechu, and 
 fifth, extract of rhatany. 8 parts of Pegu catechu are 
 found to contain as much tannin as 10, 12, 14, and 15 
 parts of the others respectively. 
 
 The characteristics of the principal varieties of catechu 
 are as follows : — 
 
 Bombay Catechu.— Firm, brittle, dark brown, of a 
 uniform texture, and a glossy, semi-resinous and uneven 
 fracture. Specific gravity, 1*39. Richness in tannin, 52 
 per cent. 
 
 Bengal Catechu. — Rusty brown colour externally ; 
 porous, and more friable than the preceding. Sp. gr. 1'28. 
 Richness in tannin, 49 "5 per cent. 
 
 Malabar Catechu. — Resembles the last in appearance, 
 
76 LEATHER MANUFACTURE. 
 
 but is more brittle and gritty. Sp. gr. 1'40. Richness 
 in tannin, 45*5. — A. J. Cooley. 
 
 Kino, or Gum Kino. — This well-known astringent sub- 
 stance is described in the British Pharmacopoeia as " the 
 juice flowing from the incised bark of the Pterocarpus 
 marsupium, or Indian kino-tree, hardened in the sun ; it 
 is also the concrete juice of Pterocarpus erinaceus (in 
 Africa), and of other undetermined genera and species/' 
 From the uniformity of its appearance, it would appear to 
 be the natural gummy exudation of some one plant, but 
 several kinds of kino are met with in commerce which are 
 known to be the products of various plants, as that of 
 Butea frondosa, from India, Botany Bay kino, produced 
 by Eucalyptus resinifera, or brown gum tree, also a 
 Jamaica and a Columbian kino, and sometimes an extract 
 of rhatany has been included in the list. The genuine 
 kino has been supposed to come from the west coast of 
 Africa, but it is understood that the best is now imported 
 from Bombay. 
 
 Kino is in small, irregular, somewhat angular, glistening 
 fragments, of a dark brown or reddish-brown colour, 
 brittle, and affording a powder which is lighter coloured 
 than the masses. It is without odour, and has a bitterish, 
 highly astringent, and ultimately sweetish taste. It is 
 not softened by heat ; cold water dissolves it partially, 
 boiling water more largely, and the saturated decoction 
 becomes turbid on cooling, and deposits a reddish sedi- 
 ment. Alcohol dissolves the greater portion. It consists 
 chiefly of a peculiar modification of tannin and extrac- 
 tive matter, and in some of the varieties, of a minute 
 portion of resin. — Royle. According to Vauquelin, it 
 contains no gallic acid, but tannin and peculiar extractive, 
 75 ; red gum, 24 ; insoluble matter, 1. Its aqueous solu- 
 tion is precipitated by gelatine (with which it produces 
 a gum, in consequence of the presence of a little cate- 
 chine), by salts of iron, &c. The alkalis favour its solu- 
 bility in water, but essentially change its nature, and 
 destroy its astringent property. Soubeiran states that kino 
 contains more tannin than Indian catechu, but less than 
 
TANNING MATERIALS. 77 
 
 Pegu catechu, and also that infusions of kino and Indian 
 catechu alike produce a brown colour with solutions of 
 perchloride of iron, with which Pegu catechu forms a 
 green. 
 
 Gambier, Gambir, or Terra Japonica (Japan earth) is 
 an extract from the plant Uncaria gambir — a native of 
 Malacca and the neighbouring islands, and was imported 
 from Singapore in 1904 to the extent of about 160,280 
 cvvts. It occurs in the market in the form of bales weigh- 
 ing about 2 cwt. each, but a superior article, called cube 
 gambier, comes to us in the form of small blocks. For a 
 long period the English tanners failed to understand the 
 proper mode of employing this agent, for when employed 
 alone, besides imparting a dark red colour to the leather, 
 it produced a soft and spongy article. It is now better 
 understood, however, and is much employed, in moderate 
 proportions, in the preliminary stages of tanning. 
 
 Hemlock Extract. — The great success of hemlock 
 tanning in the Northern States of America, has led to the 
 importation into this country of large quantities of an ex- 
 tract of this important tanning material, which is exten- 
 sively used, in combination with other tanning agents. 
 
 Chestnut Extract. — This is another comparatively 
 recent tanning material, chiefly imported from France, 
 being obtained from the wood and bark of the tree. 
 
 Oakwood Extract is now also very largely used as a 
 tanning agent, as also, 
 
 Larch Extract, or Hungarian Larch Extract, which is 
 favoured to some extent by English tanners of light 
 leathers. 
 
 Quebracho Extract, from the bark of Aspidospermum 
 quebracho, is also now largely used in Britain, Germany, 
 and America. 
 
 Sumach, or Sumac. — This much esteemed tanning 
 material — especially for light coloured leathers — is a 
 powder of the leaves, peduncles, and young branches of 
 Rhus coriaria and B. cotinus (wild olive), the product of 
 the former being employed by the tanner, more espe- 
 cially in the preparation of morocco and similar leathers, 
 
78 LEATHER MANUFACTURE. 
 
 while that from the latter is used in dyeing. Rhus 
 coriaria is a shrub growing wild in Portugal, Spain, 
 Italy, Sicily and France, which countries produce con- 
 siderable quantities of sumac, varying in quality, and 
 distinguished from each other by the habits of the plant, 
 the colour, and other properties. The shrub grows to 
 the height of from four to eight feet, with a crooked 
 stem, covered with a reddish-grey bark ; its leaves are 
 green on the upper surface and of a whitish colour on the 
 under surface during spring and summer, but they acquire 
 a reddish hue in autumn. The plant flowers in July, the 
 blossoms being of a greenish-red, and it yields clusters of 
 small crimson berries. 
 
 Sumac, as a tanning material, is chiefly preferred, 
 especially on the Continent, for its not imparting colour- 
 ing matter to the leather prepared with it. It is stated 
 that one drawback in its employment is that it deprives 
 the skin of much of its softness and pliability. In the 
 manufacture of morocco and glazed leather it is largely 
 used ; and when mixed with bark or other tanning material 
 it yields very good results. 
 
 Muspratt says : — " Of the species of sumac in the 
 market, the Sicilian is accounted the best. There are two 
 kinds, one of which, the Alcamo, is the most esteemed. 
 It is a very fine light green powder, containing very little 
 woody matter, having an agreeable odour, analogous to 
 that of the violet, and a strong astringent taste ; it con- 
 tains very little colouring matter, though it gives a yel- 
 lowish-green solution when macerated with water. The 
 second variety inclines to a reddish yellow, has a feeble 
 odour, with a less astringent taste than the foregoing 
 variety. On this account it is not much employed in 
 tanning, though extensively used in dyeing. Sicilian 
 sumac is generally packed in bales weighing about one 
 and a half hundredweight. Spanish sumac is various in 
 quality, being less carefully prepared, and consequently 
 more or less mixed with woody matter. The best sort 
 comes from Priego, and is grown in the neighbourhood of 
 Malaga. It is, like the Sicilian, finely ground, and 
 
TANNING MATERIALS. 79 
 
 affords a colour of equal or greater brightness j its odour 
 reminds one of the tea plant. "With water it gives a dark 
 and more reddish solution than the foregoing. It is 
 usually packed in bales of one cwt. The other sorts, 
 Molina and Valladolid sumac, are next in quality ; they 
 are very similar. Portuguese, or Porto, sumac is almost 
 similar to the Priego, but is generally dirtier, and con- 
 tains more mineral salts. Italian sumac has a dark 
 brown colour, is free from woody matter, but feels granular 
 in the hand, and has an odour like that of the bark, which 
 possesses similar qualities to the leaves. Prench sumac is 
 similaf to the preceding. Three sorts are collected. The 
 Fauvis is almost equal to the Sicilian when well purified, 
 and comes from Brignolles, near Marseilles. If less care 
 be taken in its manufacture it approaches more to the 
 quality of Malaga sumac ; it frequently goes under both 
 these names. A second sort, Donzeri, and a third, Piiclis, 
 are commonly used in the tanneries. A fourth variety, 
 called rodou or redoul, obtained from the Coriaria myrti- 
 folia, cultivated in Languedoc, is of a greyish-green 
 colour. 
 
 The method of preparing sumac for the market con- 
 sists in collecting the twigs of the shrub whilst in full 
 foliage and drying them in the sun. The leaves are after- 
 wards separated by threshing, and are then collected and 
 ground under mill-stones ; the powder is then packed in 
 bales for the market. Sometimes the peduncles and more 
 tender shoots are ground with the leaves, but since these 
 portions of the shrub contain a good deal of tanning prin- 
 ciple they do not much detract from the quality of the 
 material. 
 
 Rhatany Hoot. — The rhatany plant [Krameria tri- 
 andria) is a native of Peru, where it grows on the 
 slopes of the sandy mountains, more particularly near 
 Huanuco, where it was discovered by Ruiz, who found 
 that the root was employed by ladies for rubbing the teeth 
 and strengthening the gums. The root is woody and 
 branched ; the pieces vary from an inch to the size of a 
 quill. The cortical part is reddish-brown, fibrous, and 
 
go LEATHER MANUFACTURE. 
 
 easily separated from the central reddish-yellow woody 
 part. The root is without smell, but has an extremely 
 astringent taste without being bitter. The cortical por- 
 tion contains a much larger percentage of the active 
 principle than the interior ; the smaller pieces from the 
 greater proportion of the bark are the most rich in tannin. 
 An extract is sometimes imported from South America. 
 
 Rhatany root consists of one-third matters soluble in 
 water; these consist of tannin, 42*6; gallic acid, - 3 ; 
 gum, extractive and colouring matter, 56*6 ; and krameric 
 acid, 0*5. Water and alcohol both dissolve its active pro- 
 perties, forming a reddish solution. According to Gmelin 
 and Peschier, rhatany root yields : 
 
 Gmelin. Peschier. 
 
 Tannin 38-3 42-6 
 
 Gallic acid — - 3 
 
 Sweet matter 6 - 7 — 
 
 Nitrogenous matter 2-5 — 
 
 Mucilage 8 - 3 — 
 
 Lignin 43 3 — 
 
 Krameric acid — 0*4 
 
 Gum, extractive, and colouring matter — 5G - 7 
 
 99-1 100-0 
 
 Mangrove Extract. — Of late years much attention 
 has been devoted to mangrove bark and its extract. 
 The mangrove species is found growing in swamps in 
 most tropical parts of the world, the tannin-yielding 
 trees being known as Bhizophora mangle, and other allied 
 species. The trees grow in the tidal districts of East 
 India and Borneo freely, and of late years several extract- 
 ing plants have been installed in the latter country, and 
 the tannin extract exported in the form of a dry crystal- 
 live product known under various fancy names. The 
 percentage of tannin contained in the bark varies con- 
 siderably, some going as high as 45, whilst others yield 
 only 5 per cent. The catechol tannin is easily extracted, 
 but is of a deep reddish tint, which, when used alone, 
 makes an objectionable coloured leather. The extract 
 contains from 60 to 70 per cent, of tannin, and much of 
 the colour is eliminated in the course of manufacture. 
 
TANNING MATERIALS. 81 
 
 It is one of the cheapest forms of tannin now on the 
 market, and bids fair to become very popular. 
 
 Myrobalans (also called My rabolams). — The myrobalan 
 is the fruit of several species of TerminaUa, namely Termi- 
 naUa chebula, T. bellerica, T. citrina, and Emblica officinalis ; 
 these trees abound in Hindostan, Ceylon, Burmah, &c. 
 The myrobalan varies in size from that of a small hazel 
 nut to that of the nutmeg. The tannin occurs in the pulp 
 which surrounds the kernel. When employed alone in 
 tanning, myrobalans deposit a considerable quantity of 
 bloom or ellagic acid ; they are, however, generally used 
 in com mnation with other tanning materials, from their 
 usefulness in modifying the objectionable colour which 
 some of the latter impart to leather prepared with them. 
 Owing to the extreme hardness of the nut, or stone, it 
 requires to be ground by a mill specially constructed for 
 the purpose. 
 
 Valonia. — This name is given to the calyx, or cup, of 
 a large acorn, the fruit of a species of oak, Quercus cegilops, 
 which abounds in Asia Minor, Koumelia, and Greece. 
 Some botanists have recognised other varieties of Valonia 
 oak, as Quercus macrolcpis and Q. stenophylla, growing 
 in the Greek peninsula. The largest supply of valonia, 
 however, comes from Smyrna. It has been stated that 
 Palestine abounds with the valonia oak, and the late Mr. 
 Sparke Evans thought that it might be successfully 
 grown in Australia, and thus become a source of wealth 
 to that colony, which, possessing neither large rivers nor 
 extensive forests, has more need to cultivate shrubs of 
 commercial value. The suggestion is a good one, and 
 deserves to be further promulgated. 
 
 In an interesting paper in the Tanners' Journal respect- 
 ing valonia, the writer gives some very useful informa- 
 tion, from his own personal observation, from which we 
 extract the following: "The fruit begins to ripen in July, 
 and is ready for the cultivator in August. Some small 
 portion of it never attains maturity, and either falls off 
 the trees of itself, or is beaten off in the shape of camata 
 or camatina. These two trade terms signify those cups 
 
 Q 
 
82 LEATHER MANUFACTURE. 
 
 that have not opened fully, and remain with the acorn 
 stunted, and so embedded in them that it cannot be 
 
 extracted The acorns which grow in the cups are 
 
 gathered with them, but the knocking about which the fruit 
 is subjected to before it is finally despatched to Smyrna, and 
 the mere fact of drying, suffice to detach a great number 
 in the meanwhile, and the produce thus reaches our 
 market with only a small portion of them. The valonia 
 is put into sacks, and is then forwarded by camels to the 
 
 nearest railway station The valonia, having 
 
 reached Smyrna, is emptied into dry, commodious, and 
 well-aired stores specially built here for the article, and 
 then undergoes the process of picking and cleaning. This 
 is done principally by women, children, and infirm old 
 men incapable of hard work. The smaller, or ' spine,' is 
 separated from the cups, which are placed apart. The 
 former is always mixed with a proportion of earth and 
 stones collected with the fruit from the ground, and has 
 to be freed from this extraneous substance. The cups are 
 placed in large heaps before the cleaners, who rapidly 
 lay aside all the damaged cups and all the acorns, and 
 push the remainder behind them with their hands after 
 thus cleaning it. At the same time the Trieste cups are 
 quickly thrown into separate baskets, and the valonia 
 thus leaves the workers' hands in three distinct qualities — 
 Mezzana, English, and refuse. The first, however, which 
 consists of the finest large cups, is not picked out of all 
 parcels. In many cases it is allowed to remain in the 
 English quality, which then takes the name of 'natural,' 
 from the fact of its thus containing all the sound cups 
 originally produced." From this it will be seen that 
 valonia of the second quality only is exported for 
 England. 
 
 Divi divi is the pod of a leguminous shrub (Ccesalpinia 
 coriaria), a native of South America and some other 
 tropical countries ; it is also cultivated in Madras, Hin- 
 dostan, Ceylon, and other parts of India. The tannin of 
 the seed-pod exists in the tissue beneath the epidermis, 
 the seeds themselves yielding no tannin. The tannin is 
 
TANNING MATERIALS. 81 
 
 generally extracted by boiling the material in separate 
 pits, while others crush the pods in a mill, and employ 
 them as dust for the handlers. The employment of divi 
 divi in the tannery, however, appears as yet to be but 
 imperfectly understood. Containing, sometimes, nearly 
 50 per cent, of tannic acid, it should be a valuable tanning 
 agent ; but since it also possesses a considerable propor- 
 tion of mucilaginous and oily matter, it is very susceptible 
 of fermentation, especially, it is stated, in warm weather, 
 or when the atmosphere is subjected to electrical disturb- 
 ance. Tlje late Mr. Sparke Evans said : " This causes, at 
 times, much annoyance and some loss, as one of our Bristol 
 tanners found to his cost, when one day, passing through 
 his drying shed, he came to a pile of divi-tanned butts, 
 which had been laid down to temper, but through which 
 he was able to thrust his walking stick as through a 
 honeycomb. Divi-tanned leather feels firm in dry, but 
 soft in damp weather. A fortune is open to any one 
 who can employ this article in tanning and prevent 
 the dark colour which accompanies its use." To check 
 the fermentation to which divi divi is specially liable, 
 acetic acid, and more recently carbolic acid and salicylic 
 acid have been used ; a preparation called Antigalline 
 has also been used with some degree of success. 
 
 Mimosa Bark. — This material is obtained from various 
 species of Acacia — an extensive family, of which the well- 
 known Sensitive plant is a remarkable member. The spe- 
 cies from which the mimosa of commerce is derived are : — 
 Acacia molissima, A. decurrens, A. pyeantha, A. dealbata, 
 and some others. The acacias abound in Australia and 
 Tasmania, and large quantities of the bark are exported 
 to this country — by far the greatest quantity, however, 
 coming from the former colony. Mimosa is generally 
 chopped or ground previous to exportation, and it has 
 also been introduced in the form of an extract. The 
 bark contains varying proportions of tannic acid, the 
 mean being about 24 or 25 per cent. Being exceed- 
 ingly hard, the bark requires to be very finely ground 
 to extract all its tannin. It makes a red leather, and 
 
8 4 
 
 LEATHER MANUFACTURE. 
 
 is frequently used with valonia to correct the colour 
 produced by the latter. 
 
 List of Tanning Materials. 
 
 Common Name. 
 
 Botanical Name. 
 
 Part of 
 Plant used. 
 
 Where from. 
 
 Aleppo Pine . . 
 
 Algarobiall . . 
 Almardelboom 
 
 Phylanthus emhliea . . 
 Finns excelepensis .... 
 
 Beabejum stellatum . . . 
 
 Seed pod 
 Bark .... 
 Bark .... 
 Seed pod 
 
 Bark 
 
 Bark .... 
 Bark .... 
 Bark .... 
 
 Extract . . 
 
 Bark 
 
 Seed pod 
 Bark .... 
 
 Leaves . . 
 Nut .... 
 Bark .... 
 Bark .... 
 Bark .... 
 Bark .... 
 Bark .... 
 
 Nut 
 
 Extract . . 
 Bark .... 
 Extract .. 
 Bark .... 
 
 Bark .... 
 
 Bark and 
 Extract 
 
 Bark 
 
 Bark .... 
 
 Bark .... 
 Bark .... 
 Bark .... 
 Extract . . 
 Bark .... 
 Brk.ofroot 
 Seed pod 
 Bark .... 
 
 Bengal. 
 
 Spain. 
 
 Gt. Britain and Spain. 
 
 South America. 
 
 Africa. 
 
 Australia and Tasmania. 
 
 Australia and Tasmania. 
 
 British Guiana and 
 
 West Indies. 
 Bengal. 
 Hindostan. 
 South America. 
 "West Indies. 
 
 Eussia. 
 
 East Indies. 
 
 Russia. 
 
 Australia and Tasmania. 
 
 Australia and Tasmania. 
 
 West Indies. 
 
 Australia 
 
 Africa. 
 
 Bengal. 
 
 South America. 
 
 Bengal. 
 
 Australia and Tasmania 
 
 Australia and Tasmania. 
 
 N. America and Spain. 
 
 South America. 
 British Guiana and 
 
 West Indies. 
 Spain, Italy. 
 "West Indies. 
 South America 
 Bengal. 
 "West Indies. 
 Fiance. 
 
 South America. 
 South Africa. ' 
 
 Arok kenema 
 
 
 
 Balsamo .... 
 Baramalli, or 
 
 pump wood 
 Bearberrj' .... 
 Betel 
 
 Black wattle . . 
 Black wood . . 
 Blood wood . . 
 
 Carpon brevifolium . . 
 
 Arctostaphilos uva ursi 
 
 Acacia nwllissima .... 
 Acacia melanoxylon . . 
 
 Blue gum .... 
 Butea-kino . . 
 
 Eucalyptus globulus . . 
 Pyenocamamacrophylla 
 
 Celery Pine . . 
 Cherry tree . . 
 Chestnut .... 
 Cevil 
 
 Fhyllocladus aspleni- 
 
 folia 
 Exocarpus cupressi- 
 
 formns 
 
 Cork tree .... 
 Crab wood .... 
 Curmpuay .... 
 
 Avicennia nitida 
 
 Carapa guianensis .... 
 
 Cutch 
 
 Cuyama 
 
 
 Dentelaria .... 
 Divi divi .... 
 Doomboom . . 
 
 Plumbago eitropcea . . . 
 Ccesalpinia cor i aria . . 
 
TANNING MATERIALS. 
 
 85 
 
 Common Name. 
 
 Botanical Name. 
 
 Part of 
 
 Plant used. 
 
 Where from. 
 
 Galls 
 
 Quercus infectoria . . . . 
 
 Gall nuts 
 
 Turkey. 
 
 Gambier (Terr; 
 
 
 Extract . . 
 
 East Indies. 
 
 Japonica) 
 
 
 
 
 Gaub 
 
 Diospyros glutinosa . . 
 
 Root 
 
 Hindostan. 
 
 Hemlock 
 
 Abies canadensis 
 
 Bark .... 
 
 North America. 
 
 Hemlock 
 
 Geranium maculatum 
 
 Root anc 
 Extract 
 
 North America. 
 
 
 Tlceocarpus dentatus . . 
 
 Bark and 
 Extract 
 
 New Zealand. 
 
 Hog plum 
 
 
 Bark .... 
 
 British Guiana and 
 West Indies. 
 
 Holm tree, or 
 
 
 Bark .... 
 
 Italy. 
 
 Green Oak" 
 
 
 
 
 Honeysuckle . . 
 
 Banlcsia australis 
 
 Bark .... 
 
 Australia and Tasmania. 
 
 Huldi 
 
 
 Bark .... 
 
 Extract . . 
 
 East Indies. 
 
 Australia and Tasmania. 
 
 Iron bark .... 
 
 Eucalyptus resinifera 
 
 Kararalli .... 
 
 
 Bark 
 
 British Guiana and 
 West Indies. 
 
 
 
 Extract . . 
 Bark .... 
 
 France. 
 
 Kermes Oak . . 
 
 Quercus cocci/era . . . . 
 
 
 Pterocarpus marsupium 
 
 Extract . . 
 
 Africa. 
 
 Knoppern .... 
 
 Quercus pubescens .... 
 
 Galls .... 
 
 Italy and Hungary. 
 
 Krupelboom . . 
 
 Leucospermum cone- 
 carpum 
 
 Bark .... 
 
 Africa. 
 
 Kullaballi 
 
 
 Bark 
 
 Bark .... 
 
 Russia, N. America. 
 
 
 Larix americana .... 
 
 
 
 Bark 
 
 Great Britain. 
 
 
 
 Extract . . 
 Root .... 
 
 Borneo, East Indies. 
 Russia. 
 
 Marsh Rose- 
 
 
 mary 
 
 
 
 
 
 Acacia molissima .... 
 
 Extract . . 
 
 Queensland, Victoria, 
 
 
 
 
 and Tasmania. 
 
 Mocbrus .... 
 
 Bombax inalebarica . . 
 
 Extract . . 
 
 Bengal. 
 
 Molle 
 
 
 Leaves . . 
 Bark .... 
 
 South America. 
 British Guiana and 
 West India. 
 
 Mora 
 
 
 
 
 
 
 Bark 
 
 South America. 
 
 Hindostan. 
 
 Hindostan. 
 
 Myrobalans . . 
 Myrobalans . 
 
 
 Terminalia cherbu 7 a . . 
 
 Fruit . . . 
 
 Myrtle 
 
 Faqus Cunninghami . , 
 
 Bark 
 
 Australia and Tasmania., 
 
 Myrtle 
 
 Rhus myrtifolia .... 
 
 Bark .... 
 
 Italy. 
 
 Neb neb 
 
 Acacia nilotica 
 
 Seed pod 
 
 Africa, Nubia. 
 
 Oak 
 
 Quercus pedunculata . . 
 
 Bark .... 
 
 Great Britain. 
 
 Oak 
 
 Quercus sessiliflora . . . 
 
 Bark .... 
 
 Great Britain. 
 
 Olive 
 
 
 Bark .... 
 
 Italy. 
 
 Palacby 
 
 
 Extract . . 
 
 East Indies. 
 
 Pomegranate 
 
 Tunica qranatum .... 
 
 Fruit shell 
 
 Hindostan. 
 
 Purimbaa .... 
 
 Fusarmis compressus . . | 
 
 Bark .... 
 
 Africa. 
 
86 
 
 LEATHER MANUFACTURE. 
 
 Common Name 
 
 Botanical Name. 
 
 Part of 
 Plant used. 
 
 "Where from. 
 
 Quebracho . . 
 
 . Aspidospermum que- 
 bracho 
 
 Bark .... 
 
 South America. 
 
 Quercitron 
 
 . Quercus tinctoria .... 
 
 Bark .... 
 
 North America. 
 
 Red birch . . 
 
 . Coriaria ruscifolia . . . 
 
 Bark .... 
 
 New Zealand. 
 
 Red birch . . 
 
 . Eugenia maire 
 
 Bark .... 
 
 New Zealand. 
 
 Red birch , . 
 
 
 Bark 
 
 New Zealand. 
 
 Rhatanv . . 
 
 . Krameria triandria . . 
 
 Root .... 
 
 South America. 
 
 Saffron .... 
 
 . Crocoxylon excelsum . . 
 
 Bark 
 
 Africa. 
 
 Sassafras . . 
 
 . Atherospermamoschata 
 
 Bark 
 
 Australia and Tasmania. 
 
 Saul tree . . 
 
 
 Bark .... 
 
 East Indies. 
 
 Seaside grape 
 
 
 Bark .... 
 
 British Guiana and 
 West Indies. 
 
 
 . Casuarina quadrivalvis 
 
 Bark 
 
 Australia and Tasmania. 
 
 Silver wattle 
 
 
 Bark 
 
 Australia and Tasmania. 
 
 Sirnabelli . . 
 
 . Nectandra 
 
 Bark .... 
 
 British Guiana and 
 West Indies. 
 
 
 
 
 Bark .... 
 Bulb .... 
 
 East Indies. 
 Africa. 
 
 
 
 Statice,orMrs 
 
 
 Root .... 
 
 Russia, North America 
 
 rosemary 
 
 
 
 
 Stone pine. . 
 
 
 Bark .... 
 
 Spain. 
 
 Subaujuna. . 
 
 . Moving a pterygosperma 
 
 Bark .... 
 
 Hindostan. 
 
 
 
 Leaves and 
 twigs 
 
 France, Italy. 
 
 Tamarisk gall 
 
 
 Galls .... 
 
 East Indies. 
 
 
 
 Bark 
 
 Bark .... 
 
 New Zealand. 
 North America. 
 
 Tarsekeha . . 
 
 . Phyllocladus tricho- 
 
 
 manoides 
 
 
 
 Tasman. laurf 
 
 il Anopterus glandulosa 
 
 Bark .... 
 
 Australia and Tasmania. 
 
 
 
 Seed pod 
 Extract . . 
 
 East Indies, 
 
 Terra Japonic 
 
 
 Bengal. 
 
 Tormentil . . 
 
 . Tormentilla potentilla 
 
 Root .... 
 
 Spain. 
 
 
 . Weinmannia racemosa 
 
 Bark 
 
 New Zealand. 
 
 Tuga veca . . 
 
 . Stryphnodendron bar- 
 batemas 
 
 Bark 
 
 South America. 
 
 
 . Cassia auriculata .... 
 
 Bark 
 
 Hindostan. 
 
 
 
 Acorn cup 
 
 Turkey. 
 
 "Wagen boon 
 
 l . Protea grandiflora .... 
 
 Bark 
 
 Africa. 
 
 Water plain 
 
 - Polygonum amphibium 
 
 Root .... 
 
 North America. 
 
 tain 
 
 
 
 
 White man 
 
 - Avicennica tormentosa 
 
 Bark 
 
 South America. 
 
 Willow .... 
 
 
 Bark .... 
 Bark 
 
 France. 
 France. 
 
 
 Miscellaneous Tanning Materials. — The shell of the 
 seed of Sapindus emarginatus, an East Indian plant, is said 
 
TANNING MATERIALS. 87 
 
 to contain 31 per cent, of tannin. Samples of the African 
 gall nut of Tamaria are said to contain 56| per cent, of 
 tannin. The bark of Tamaria gallica gave, on analysis, 
 3 - 52 per cent, of tannin, and the bark of Terminalia Jbr- 
 mentosa, of the same family as that from which myrobalans 
 are obtained, is reputed to yield 26 per cent, of tannin. 
 The bark of the common alder (Alnus glutinosa) is said to 
 yield about 16 per cent, of tannin. The Eucalyptus leu- 
 coxylon, or iron-bark of Victoria, yields about 22 per cent. 
 of kinotannic acid ; Eugenia Smithii, or Australian 
 myrtle-tree, is said to contain 17 per cent, of tannic acid, 
 with frgm 3 to 4 per cent, of gallic acid. The shells of 
 the pomegranate fruit yield about 13 per cent, of tannic 
 acid. 
 
CHAPTER VIII. 
 
 ESTIMATION OF TANNIN 
 
 Examination of Bark. — Determination by Specific Gravity. — The Barko- 
 meter. — Chemical Methods of Estimating Tannin. — Davy's Method. — 
 Bell Stephens' Method. — Hammer's Method.— Lowenthal's Method. — 
 Mr. Hewitt on Lowenthal's Method. — Mr. Procter on Lbwenthal's 
 Method. — Ramspaoker's Method. The Tannometer. — Casali's Pro- 
 cess. — Standard Method. — International Association of Leather 
 Trades' Chemists. 
 
 When we consider the vast number of tan-yielding vege- 
 tables which have been brought to the tanner's notice since 
 the days when Davy first investigated the subject, the 
 variable characteristics of the different tannins, as shown by 
 Gmelin, Stenhouse, Procter, and others, and the difference 
 in the percentage of tannin in the various plants, or parts of 
 plants, which enter the market for his use, it will at once 
 become evident that the tanner should be in possession of 
 some means by which he may estimate the true value of 
 all tanning materials with which he may have to deal. 
 Moreover, when it is borne in mind that the proper condi- 
 tion of the tanning material may be seriously affected by 
 damp or long exposure to the air, by which its active 
 principle becomes converted into a product useless to the 
 tanner, it is of the highest importance that the true per- 
 centage of the active principle (tannin) should be deter- 
 mined from a fair or average sample, before the bulk of 
 the material — no matter from what source — is purchased 
 and paid for. 
 
 With a view to aid those who may desire to test the value of 
 their tanning materials, we purpose giving — as free as pos- 
 sible from unexplained technicalities — some of the methods 
 adopted, commencing with those of the most simple cha- 
 
ESTIMATION OF TANNIN. 89 
 
 racter. Before doing so, however, it may be well to con- 
 sider what are the proper physical characteristics of the 
 leading tanning material — oak-bark. 
 
 Examination of Bark. — The bark is usually in long 
 strips, of a coarse fibrous texture, and not easily reduced to 
 powder. When deprived of its epidermis, it is of a light 
 brown colour externally. The odour is faint, but the taste 
 bitter and very astringent. — Royle. A good bark is 
 known by its colour. The most highly esteemed is that 
 which is white outside and reddish inside, rough and dry 
 on the side of the wood, breaks easily, and gives less 
 ligneous-( woody) matter ; the taste most astringent with a 
 strong smell when ground. A sign of bad quality is 
 when the epidermis and cortex (bark) are very thick 
 and have a blackish colour ; in this case the bark is too 
 old, and has experienced the commencement of decay. 
 It is the same with bark which has been left a long 
 time exposed to rain. The inner side, which should be 
 reddish, has lost its colour, and the other parts, which 
 have become darkened, have lost a part of their property. 
 — Dussauce. 
 
 Determination by Specific Gravity. — It is well known 
 that in all arts in which solutions of chemical sub- 
 stances of various degrees of strength are employed, the 
 approximate strength of the solutions is determined 
 by means of an instrument called a hydrometer. This 
 instrument consists of a long glass tube with a small 
 bulb partly filled with mercury or small shot at its lower 
 end, and a somewhat larger bulb at a short distance above 
 the mercury bulb. A graduated paper scale is enclosed 
 in the longer stem of the tube, which is divided into tenths. 
 When the hydrometer is floated in distilled xoater, it sinks 
 to the top of the scale, which is marked 1,000 or (zero) — 
 the specific gravity of water. This is taken as the standard by 
 which the specific gravity of all other fluids is determined. 
 Since alcohol and ether, however, are lighter than water, 
 it is evident that such an instrument would not be of ser- 
 vice in determining their strength or specific gravity; 
 therefore, hydrometers for ascertaining the specific gravity 
 
9 o 
 
 LEATHER MANUFACTURE. 
 
 of liquids lighter than water are constr acted for the use of 
 distillers, manufacturing chemists, and others. 
 
 The Barkometer. — To enable the tanner to ascertain 
 the tanning strength of his liquors, an instrument has 
 been devised, called a barcometer or barkometer, and is due 
 to the ingenuity of Mr. W. Pike, of New York. It is thus 
 described by Morfit : — 
 
 " It is made wholly of glass * (see Fig. 3), a d being 
 the stem, enclosing a graduated paper scale ; B is a 
 spherical bulb, and C a smaller bulb at 
 its base, containing quicksilver or shot, 
 which serves as ballast to retain the 
 instrument in a vertical position in the 
 liquid. The scale on the stem is equally 
 divided into five or ten wide spaces, and 
 each of these again subdivided into ten 
 narrow spaces. The zero point of the 
 scale is made by plunging the instru- 
 ment into distilled water at 58° Fahr., 
 and adding mercury to the bulb until 
 it sinks to nearly the top of the stem 
 at a. A solution of ten parts of bark in 
 ninety parts of distilled water having 
 been made, the hydrometer is then 
 plunged into the liquor, and the point 
 to which it sinks therein, say b, is 
 carefully and accurately marked upon 
 the scale and rated at ten as compared 
 with the zero point. Each of the 
 grand divisions consequently repre- 
 sents ten per cent, of bark, and each of 
 the smaller ones or subdivisions corre- 
 sponds with one per cent, of the bark. It is very easy, 
 therefore, after having determined the length of the stem 
 from zero which sinks in a normal solution of bark, to ap- 
 portion the rest of it with the aid of a pair of dividers, 
 so that every interval thus apportioned shall be equal to 
 that fixed by experiment. 
 
 * Crass barkometers are now often used in the tanyard. — Ed. Fifth Edition 
 
 Pis:. 3. 
 
ESTIMATION OF TANNIN. 
 
 9' 
 
 "When, therefore, this instrument sinks into a bark 
 liquor to 20°, 30°, or any other degree, the number indi- 
 cates the percentage of tanning 
 power. [A convenient form of 
 hydrometer glass is shown in 
 Fig. 4.] It is necessary to ob- 
 serve that this instrument is 
 applicable only to freshly made 
 liquors, for otherwise confusion 
 and want of confidence might 
 ensue upon finding that it 
 sinks, sometimes to a corre- 
 sponding degree, in spent liquor. 
 This is owing to the fact that 
 the alterations which tanning 
 liquors undergo during use and 
 exposure may not diminish their 
 density, though they impair or 
 destroy their tanning power." 
 Indeed, the accumulation of 
 gallic acid, vegetable extractive, 
 and other constituents of bark 
 in much-used liquors, would 
 render the barkometer practi- 
 cally useless as an indicator of 
 
 the presence of tannic acid. It should therefore only be 
 employed in testing the strength of fresh liquors, and even 
 then the liquors should always be tested at the mean tem- 
 perature of 60° Fahr., since the gravity of the liquors is 
 greatly influenced by their temperature. 
 
 Chemical Methods of Estimating Tannin. — The earlier 
 methods of determining the percentage of tannin in vege- 
 table substances were based upon the well-known affinity 
 of this substance for gelatine ; but it was soon discovered 
 that when solutions of tannin and gelatine were mixed 
 together, the first precipitate of tanno- gelatine contained 
 a larger percentage of tannin than the last, and conse- 
 quently the gelatine test was open to objection where 
 absolute accuracy was required. This method of forming 
 
92 LEATHER MANUFACTURE. 
 
 an approximate estimate of the percentage of tannin, how- 
 ever, is useful in cases where the higher chemical testa 
 would not be so readily understood. 
 
 Davy's Method. — One ounce of dry bark is reduced to 
 a fine powder and digested in a pint of boiling water, with 
 frequent stirring. After twenty-four hours' repose, the 
 clear liquor is filtered through a cloth. Now dissolve one 
 drachm of the best isinglass in one pint of warm water 
 with stirring ; add the isinglass to the water gradually, 
 to prevent it from agglutinising. Take equal quantities 
 of these two liquors and mix them together ; a flaky pre- 
 cipitate is at once formed. The mixture must now be 
 filtered and the precipitate collected, dried, and weighed. 
 The difference of weight indicates the proportion of 
 tannin. The precipitate (tanno-gelatine) generally con- 
 tains forty per cent, of tannin. 
 
 In examining this method of estimating tannin, Mr. 
 Bortwick found that much of the precipitated gelatine 
 remained in the filtered liquor, and could not be separated 
 by the filter, and also that the first portions of the preci- 
 pitate contained 50 per cent, of tannin, while the latter 
 portions contained very little. There is no doubt, how- 
 ever, that Davy's estimate was based upon the fact that 
 the precipitate was a compound of gelatiDe and tannin, and 
 if the weight of the first was known, the difference in 
 weight, after careful drying, must of necessity be the weight 
 of tannin absorbed. 
 
 Davy also suggested the following method : A piece of 
 skin is dried and weighed ; it is then immersed in the 
 liquor containing tannin for some hours, after which it is 
 dried and weighed again. The increase in weight gives 
 the quantity of tannic acid. 
 
 Bell Stephens' Method. — This plan, originally sug- 
 gested by Davy, is based upon the power of skin to absorb 
 tannin. A piece of skin, dried over a hot- water bath, is 
 carefully weighed. It is then soaked in water at about 
 90° Fahr., until perfectly soft, and is next immersed in a 
 weak solution of the tannin to be examined, which should 
 be heated to about 90° Fahr. In about seven or eight 
 
ESTIMATION OF TANNIN. 93 
 
 liours the skin will have absorbed all the tannin, when it 
 is again dried and weighed. The increase in weight 
 acquired by the skin indicates the quantity of tannin it 
 has absorbed. One advantage of this process is that the 
 appearance of the skin, after being thus partially tanned, 
 shows what colour the tanning material would impart to 
 leather prepared by its agency. 
 
 Another method of estimating the strength of tannins, 
 upon the above principle, is to take a given weight of 
 dried shavings of unhaired skin, to immerse them in warm 
 water until thoroughly softened, and then to place them 
 in a weak and warm infusion of the tanning material to be 
 examined. After a few hours' immersion the fragments 
 of skin are withdrawn and carefully dried over a water- 
 bath ; when perfectly dry they are again weighed, when 
 the difference in weight will show the amount of tannin 
 which has been absorbed. Of course it is absolutely neces- 
 sary, in adopting these methods of ascertaining the per- 
 centage of tannin, to leave the skin sufficiently long in 
 the liquor to absorb all the tannin ; and in order that this 
 should be determined with certainty, a few drops of a solu- 
 tion of gelatine may be added to the liquor after the skin 
 has been removed, when, if no turbidity is produced by 
 the gelatine, it may be concluded that the skin has taken 
 up all the tannin. Again, it is of paramount importance 
 that the skin, or fragments of skin, should be absolutely 
 dry at the time of weighing, otherwise all calculations 
 will be misleading. 
 
 Hammer's Method. — The specific gravity of the tannin 
 solution to be tested is first ascertained by means of the 
 hydrometer before referred to. This will show the density 
 of the solution as compared with water (1000). The 
 tannin is next removed from the solution by immersing 
 skin in it until all the tannin has become absorbed. The 
 hydrometer is now again placed in the liquor, when the 
 decrease in its density or specific gravity will be pro- 
 portionate to the quantity of tannin in the original 
 solution. 
 
 Besides the above methods of estimating tannin, which 
 
94 LEATHER MANUFACTURE. 
 
 may be considered to give fairly approximate rather than 
 actual results, there have been many processes of a more 
 purely chemical character introduced from time to time, 
 from which we will select the one which has found most 
 general acceptance as a reliable method in the hands of 
 persons accustomed to laboratory manipulation. We refer 
 to the process of L6 wen thai, which has been the subject 
 of much consideration, and also to some modifications by 
 which it has been rendered somewhat more easy of ma- 
 nipulation. 
 
 Lbwenthal's Method.— This method of estimating the 
 percentage of tannin is generally accepted as reliable, 
 though of a . somewhat complicated character. It is based 
 upon the oxidising power of permanganate of potash ; and 
 this system of analysis by oxidation is termed titra- 
 tion. The material to be examined being mixed with 
 an oxidisable substance, as indigo, for example, is titrated 
 with the oxidising agent, which in Lowenthal's pro- 
 cess is permanganate of potash. The process is thus 
 described : * — " The instruments required, besides a 
 good balance and a few glass beakers and funnels, are 
 merely a flask gauged at the neck to hold a litre,f a 
 few pipettes and graduated glasses, and a Mohr's burette 
 with a glass tap. The latter is simply an upright tube 
 with a tap at the bottom, graduated down the side like a 
 measuring- glass, and the most suitable size for the purpose 
 is one delivering twenty-five cubic centimetres, and divided 
 into two hundred and fifty parts. 
 
 " The following solutions must be prepared : I. Four 
 grammes of pure permanganate of potash in three litres 
 of distilled water. II. Five grammes of pure 'precipitated 
 indigo ' in one litre of water. III. Dilute sulphuric acid 
 — one part acid to three parts water. IV. Twenty-five 
 grammes of good transparent glue, well swollen in cold 
 water, and then dissolved by gentle heat, the solution 
 being made up to one litre with water and saturated with 
 pure table- salt. Y. A saturated solution of pure salt con- 
 
 * Tanners and Curriers' Journal, March, 1877. 
 f See French Tables of "Weights and Measures. 
 
ESTIMATION OF TANNIN. 95 
 
 taining twenty-five cubic centimetres of sulphuric, or fifty- 
 cubic centimetres of hydrochloric acid per litre. 
 
 " Although this seems rather a formidable list, it is not 
 a costly one, and all the solutions may be kept for a long 
 time in stoppered ' Winchester ' bottles. To make an 
 analysis, 10 grammes of sumach or 20*25 grammes of bark 
 are exhausted by boiling with water, and the solution, 
 when cold, made up to one litre. Of this infusion, 10 cubic 
 centimetres are mixed with, say three-quarters of a litre 
 of water, 25 cubic centimetres of the indigo solution, and 
 10 cubic centimetres of the dilute sulphuric acid are added, 
 and theri*the permanganate solution is run in drop by drop 
 from the burette, with constant stirring, till the deep blue 
 of the indigo changes to a clear yellow, and the moment 
 this takes place we note the quantity of permanganate 
 used. We will call this A. Next we repeat exactly the 
 same process with the indigo and sulphuric acid alone, 
 and we will call this quantity B. Then subtracting B 
 from A, we obtain the amount of permanganate consumed 
 by the total astringent of 10 cubic centimetres of our 
 tannin infusion. The permanganate acts, of course, as an 
 oxidising agent, oxidising and consuming both the tannin 
 and the indigo; but as the tannin is the most readily 
 oxidised of the two, it is consumed first, and when the 
 indigo is all bleached [decoloured], we may be sure that 
 the tannin is destroyed also. In order, however, to obtain 
 this satisfactorily, the proportion of indigo should be such 
 as to require about twice the quantity of permanganate 
 which should be consumed by the tannin alone. Thus, if 
 the indigo alone requires 10 cubic centimetres of perman- 
 ganate to decolourise it, the indigo and tannin infusion 
 together must not take more than about 25 cubic centi- 
 metres, and if it does so the tannin infusion must be 
 diluted accordingly, or a less quantity employed. 
 
 " The next step is to ascertain the proportion of gallic 
 acid and impurities in the sample. To this end we mix 
 100 cubic centimetres with 50 cubic centimetres of the 
 salted gelatine solution, and then, after well stirring, add 
 100 cubic centimetres of the salt and acid solution, and 
 
96 LEATHER MANUFACTURE. 
 
 leave the mixture standing for some hours, or all night, 
 and then filter it through filtering-paper. The filtrate 
 should be perfectly clear. If we now test, say 50 cubic 
 centimetres of this filtrate with permanganate and indigo, 
 as before, we shall obtain the amount of permanganate 
 required for the gallic acid and impurities alone, since the 
 tannin has been entirely precipitated, and the gelatine has 
 so trifling an action on the permanganate that it may be 
 safely neglected. To make the working clearer we will 
 take an example from Mr. Lowenthal's paper : — 
 
 Ten grains of sumach were boiled in § litre of water, and after cooling, 
 were made up to 1 litre. 
 
 1-10 c.c. sumach infusion ) , „„ „ . 
 
 25 c.c. indigo solution ) consumed 16-6 c.c. permanganate. 
 
 The same repeated 16-5 ,, „ 
 
 33-1 
 Indigo alone 1 3 - 2 
 
 Total permanganate for 20 c.c. ) __ „ 
 sumach i 
 
 2*50 c.c. nitrate from the \ 
 
 gelatine | consumed 11*2 c.c. permanganate. 
 
 25 c.c. indigo solution ) 
 
 The same repeated 11-1 ,, „ 
 
 92-3 
 
 50 c.c. indigo alone 13-2 ,, 
 
 Gallic acid and impurities 9 - l ,, 
 
 " Now, deducting 9*1 cubic centimetres from 19 - 9 cubic 
 centimetres, we have 10*8 cubic centimetres as the per- 
 manganate equivalent to the tannin of 20 cubic centi- 
 metres of sumach infusion, or - 2 gramme of dry sumach. 
 If it be desired to compare two sumachs, these propor- 
 tional numbers are all that is necessary, and indeed it 
 will be quite safe to use them for comparing sumach 
 with galls or pure tannin. In the same way bark may 
 be compared with bark, and valonia with valonia, but 
 it will not be safe to attempt by this means to com- 
 pare bark with sumach or with valonia, because the dif- 
 
ESTIMATION OF TANNIN. 97 
 
 ferent species of tannin consume different proportions of 
 permanganate." 
 
 Mr. Hewitt on Lbwenthal's Method. — With a view to 
 testing- the accuracy of the results obtained by Lowenthal's 
 method, Mr. F. W. Hewitt, of the Boyal College of Che- 
 mistry, made a series of experiments with different tanning 
 materials, and communicated the results of his labours to the 
 journal referred to,* from which we make a few extracts. 
 Mr. Hewitt observes : — " 1. The indigo-carmine solution 
 employed must be quite free from suspended or undissolved 
 matter. A convenient strength to use is such that 20 cubic 
 centimefres thereof shall require about 12 cubic centimetres 
 of permanganate solution (1*5 gramme of the salt to the 
 litre). 750 cubic centimetres of water should be used to 
 dilute this quantity of indigo, as the changes of colour 
 from the blue to the various shades of green, and lastly 
 yellow, are more distinct than if the solution be more con- 
 centrated. A moderate amount of dilute sulphuric acid 
 added to the indigo does not influence the reaction." Mr. 
 Hewitt prefers, instead of using a beaker glass for the titra- 
 tion of the permanganate solution, to employ a large flask, 
 capable of holding about 48 ozs., and to agitate the con- 
 tents by giving them a rotary motion during the reaction. 
 He further observes, that if the permanganate solution 
 "be run from the burette somewhat quickly, a slightly 
 different reading can be obtained from that which is 
 obtained when it is slowly introduced. When the approxi- 
 mate amount of permanganate required is known, one cubic 
 centimetre may be run in at a time, and the flask shaken, 
 as before, about six times between each addition of per- 
 manganate. In this manner more uniform readings are 
 obtained." Mr. Hewitt says, that in precipitating the 
 tannin by gelatine, Lowenthal's dilute acid solution "must 
 not on any account be deviated from, as a more concen- 
 trated acid (hydrochloric) would act upon the permanga- 
 nate and liberate chlorine." 
 
 Mr. Hewitt states that one objection to Lowenthal's 
 method is that the gelatine solution requires a certain 
 * Tanners' Journal, April, 1877. 
 
 a 
 
98 LEATHER MANUFACTURE. 
 
 amount of permanganate in the presence of free acid. 
 This he observed by adding a little permanganate to an 
 acidulated aqueous solution of gelatine, when the colour 
 was discharged. " If the same tannin infusion be used in 
 duplicate analyses with the same gelatine, I obtained very 
 clear results, even when slightly different strengths of 
 indigo were employed. Both indigo solutions, though of 
 only slightly different degrees of concentration, should be 
 previously titrated with permanganate solution." 
 
 Mr. Hewitt gives the following result of his analyses, in 
 conducting which he employed the same infusion of tannin 
 and the same gelatine solution. The results are expressed 
 in accordance with Lowenthal's proposition — namely, in 
 percentage of oxidisable matter : — 
 
 I. Sumach Infusion. 
 
 l. 2. 
 
 Tannin 45-3 45-8 
 
 Oxidisable matter, not tannin 54-7 54-2 
 
 II. Galls Infusion. 
 
 Tannin 75-2 75-0 
 
 Oxidisable matter, not tannin 24-8 25 - 
 
 III. Oak-Bark Infusion. 
 
 Tarnin . 87-3 87'3 
 
 Oxidisable matter, not tannin 12-7 12-7 
 
 In pursuing his experiments further, Mr. Hewitt found 
 that the tanning material under examination should be 
 boiled several times, with successive small portions of 
 water, in order to obtain constant results in the deter- 
 mination of the respective amounts of oxidisable matter 
 present, and that a simple infusion in hot water did not 
 afford such results. He also urges that the sample to be 
 examined should be intimately mixed, so as to obtain a fair 
 average in the portion to be examined. " In reference to 
 the salted gelatine solutions," says Mr. Hewitt, " if the 
 gelatine be not heated for a sufficient length of time on 
 
ESTIMATION OF TANNIN. 99 
 
 the water-bath, with common salt solution, it assumes, on 
 cooling, a jelly-like condition, and the solution from the 
 precipitate which is formed when the gelatine solution is 
 added to the tannin infusion, niters neither quickly nor 
 clearly. This can, however, be entirely obviated by using 
 a gelatin solution of a perfectly fluid consistency." He 
 also says that he has not found any advantage in 
 allowing the precipitate to stand for several hours, as 
 recommended by Lo wen thai, to obtain a perfectly clear 
 filtrate. He thinks that half an hour is sufficiently long, 
 whereby the operation of testing tanning materials is con- 
 siderably accelerated. The following results were ob- 
 tained by Mr. Hewitt from the same sample of sumac, 
 intimately mixed, and completely extracted. The strength 
 of each of the four respective infusions being about h 
 Grammes to the litre. 
 
 Oxidisable matter, not tannin 
 
 1. 
 
 59-5 
 40-5 
 
 2. 
 ,59-2 
 40-8 
 
 3. 
 59-64 
 40-36 
 
 4. 
 59-68 
 40-32 
 
 100- 100- 100- 100- 
 
 " It will, I hope, be allowed," observes Mr. Hewitt in 
 conclusion, "by your practical readers, that a method 
 which yields such results under the conditions which T 
 have endeavoured to trace may well be called a useful 
 method." 
 
 The above results, based upon a careful and exhaustive 
 series of experiments, clearly indicate the usefulness of 
 Lowenthal's method of testing tanning materials, espe- 
 cially when subject to the modifications which Mr. Hewitt 
 has so ingeniously introduced. The difficulty which some- 
 times arises, however, of separating minute particles of 
 tanno- gelatine, which obstinately remain suspended in 
 the filtrate, and thereby affect the accuracy of analyses in 
 some degree, has frequently been a source of trouble in 
 this and other cases in which gelatine has been employed 
 to precipitate tannin. To overcome this, Prof. H. E. 
 Procter hit upon the happy idea of mixing kaolin (china 
 clay) with the liquid before filtration, the effect of which, 
 
 LOFC. 
 
100 LEATHER MANUFACTURE. 
 
 he says, " was instantaneous and complete. A perfectly 
 clear filtrate was obtained without any of the tedious 
 waiting which before was necessary, and it was not only 
 free from tannin, so far as I have been able to ascertain, 
 but also nearly so from gelatine, so that it only gives the 
 faintest cloudiness with tannin solution." Kaolin is 
 constantly used by photographers to remove the brown 
 colour derived from the action of nitrate of silver upon 
 albumenised paper, from their sensitising solutions, which 
 it does effectually and instantaneously. A pinch or two 
 of kaolin is put into a pint of discoloured sensitising 
 solution, the bottle well shaken, and the solution at once 
 filtered, when it passes through the filter perfectly bright 
 and colourless. 
 
 Prof. Procter on Lowenthal's Method.— Prof. Procter* 
 thus describes the system he adopts in working Lowen- 
 thal's method: — "I employ permanganate of the strength 
 of 1 gramme per litre, and solution of the purest indigo- 
 carmine of 5 grammes, with 50 cubic centimetres of 
 concentrated sulphuric acid per litre, using a 25-cubic 
 centimetre burette, and 20 cubic centimetres of indigo 
 solution, which consumes about 15 cubic centimetres of 
 permanganate. The quantity of astringent used must not 
 require more than the remaining contents of the burette. 
 The titration is performed in a white basin, as recom- 
 mended by Kathreiner, with about three-quarters of a litre 
 of good water, which it is best to measure approximately, so 
 that if it contains any impurity which affects the per- 
 manganate it should be constant, and thus eliminated with 
 the indigo. The titration is finished when the pure yellow 
 liquid shows a faint pinkish rim. This acid reaction, 
 which is of extraordinary delicacy, is due to Kathreiner, 
 and is quite different to the pink caused by excess of 
 permanganate, being an effect common to all pure yellow 
 liquids. I do not find it needful to make the titration so 
 slowly as has been advised; the permanganate may be 
 dropped rapidly, with vigorous stirring, so long as there 
 is large excess of indigo, but as soon as the bottom of 
 * Journal of the Society of Chemical Industry. 
 
ESTIMATION OF TANNIN. 101 
 
 the basin can be seen through the solution it must be 
 added very cautiously and with occasional pauses, to 
 allow time for its complete mixture through so large a 
 mass of fluid. 
 
 "I make my infusion of such a strength that I can 
 employ 5 cubic centimetres of the original liquid for each 
 titration. This is repeated twice, and the results added 
 together and denoted a. I then take 50 cubic centimetres 
 of the infusion, and add 28 - 6 cubic centimetres of a freshly 
 made solution of Nelson's gelatine of 2 grammes to 100 
 cubic centimetres. After shaking, the mixture is satu- 
 rated with salt, which brings the volume up to 90 cubic 
 centimetres, and 10 cubic centimetres of dilute sulphuric 
 acid (containing one volume of concentrated acid in ten) 
 and a teaspoonful of pure kaolin are added. It is best to 
 do this in a flask in which it can be well shaken, after 
 which filtration may be at once proceeded with. Ten cubic 
 centimetres of this filtrate ( = 5 cubic centimetres of the 
 original infusion) are employed for a second pair of titra- 
 tions, which are added as before, and the result denoted b. 
 If, further, c be the quantity of permanganate required to 
 oxidise 10 cubic centimetres of decinormal oxalic acid, and 
 10 grammes of substance have been employed to one litre 
 of infusion, c : [a — b) : : 6*3 : x, where x is the percent- 
 age of tannin expressed in terms of crystallised oxalic acid. 
 For the present I invariably calculate my results in this 
 way, since we do not actually know the relation of any 
 single tannin to permanganate, even Neubauer's number 
 for gallo-tannic acid being probably too high, and Oser's 
 for quercitannic acid being only a fair approximation. It 
 happens, moreover, that this last equivalent (62 - 36) does 
 not differ from that of oxalic acid (63) more than the ordi- 
 nary limits of error of such estimation, and the substitution 
 is therefore of no commercial importance, while it is 
 surely better to employ a standard which is easily and 
 exactly verified than one which is certain to be modified 
 by further research, and so to run the risk of either having 
 our results made useless for further comparisons or of 
 establishing a false and arbitrary equivalent. What is 
 
ios LEATHER MANUFACTURE. 
 
 wanted for practical purposes is not the absolute weight 
 of tannin in the various materials, but only a means for 
 the relative comparison of two samples of the same mate- 
 rials, cross comparisons of different tannins being simply 
 delusive." 
 
 Hamspacker's Method. The Tannometer. — The fol- 
 lowing is Dr. John Watts' s description of Muntz and 
 Ilamspacker's apparatus, called a tannometer, for esti- 
 mating tannic acid, by which the actual tanning power of 
 any tanning material may be determined — " The appa- 
 ratus may be briefly described as a shallow gun metal 
 drum of about 200 cubic centimetres capacity, per- 
 manently closed at one end by an india-rubber plate, and 
 capable of being closed watertight at the other end by a 
 piece of depilated hide, when clamped upon a stand over 
 which the skin has been previously stretched. 
 
 "The drum is perforated at the side with a screw, to 
 admit the introduction of the tanning liquor, and is fitted 
 above with a screw-piston to compress the india-rubber 
 disc. When the piston is lowered the liquor is forced 
 through the skin, while the latter retains the whole of the 
 tannic acid. The density of the liquor is taken before and 
 after the operation by means of a very fine hydrometer 
 graduated to a special scale, when the difference expresses 
 at once the percentage value of the liquor operated upon. 
 In order to compare the results of this tannometer with 
 Hammer's table of percentages of tannin in solutions of 
 different densities, and to compare both with the results 
 by evaporation, a number of experiments were undertaken 
 by the inventor. The percentages only indicate the value 
 of the particular sample under examination. The numbers 
 in the first column were obtained hj taking the specific 
 gravity at 15° C. (59° Fahr.) before and after removing the 
 tannin and obtaining the percentage equivalent from Ham- 
 mer's table. The third column was found by evaporating 
 25 cubic centimetres in a platinum dish before and after 
 the removal of the tannin, and drying the residue for three 
 or four hours at 100° G. (212° Fahr.). 
 
By 
 
 By 
 
 Tannometer. 
 
 Evaporation 
 
 . . . . 40-44 . 
 
 .. 47-43 
 
 . . . . 30-50 
 
 .. 49-02 
 
 44-60 . 
 
 . . 52-16 
 
 25-32 . 
 
 .. 26-30 
 
 . ... 30-28 . 
 
 .. 31-08 
 
 30-16 . 
 
 .. 31-72 
 
 . ... 59-10 . 
 
 — 
 
 . ... 52-41 
 
 . 57-90 
 
 18-00 . 
 
 . . 19-55 
 
 ... 33-94 . 
 
 .. 35-20 
 
 ESTIMATION OP TANNIN. 103 
 
 By Specific 
 Gravity, 
 
 Cube Gambier 41-45 
 
 Bale „ 42-24 
 
 Cutch 47-70 
 
 Valonia 25-32 
 
 Myrobalans 32-30 
 
 Mimosa bark 31-44 
 
 Blue galls 6060 
 
 Green,, 53-40 
 
 Sumac 17-10 
 
 Divi divi 34-50 
 
 Casali's Process.— This is founded on the fact that a 
 neutral*solution of sulphate of nickel, containing a salt of 
 ammonium, completely precipitates tannin from its solu- 
 tions, forming flocks which easily collect together. He 
 prepares his standard solution as follows : — 2 - 89 grammes 
 of pure sulphate of nickel, previously dried at 518° to 572° 
 Fahr., are dissolved in boiling water with the addition of 
 a few drops of sulphuric acid, and 100 cubic centimetres 
 of a 30 per cent, solution of sulphate of ammonia are 
 added. One-half the mixture is mixed, drop by drop, 
 with ammonia, until it assumes a violet-blue colour. The 
 other half is then added, and the whole diluted to one 
 litre. The solution is not affected by glucose, glycerine, 
 tartar, or alkaline oxalates and succinates. One cc. pre- 
 cipitates 0'01 gramme of the tannin of galls, or 0*01497 
 gramme of the tannin of oak bark. To determine the 
 tannin, the sample of ware — 20 grammes, if it be supposed 
 to contain 6 — 10 per cent., and 10 grammes or less if it 
 contains more — is powdered and extracted with water at 
 168° to 176° Fahr., so that the total bulk of the filtered 
 solution may make up yo^ litre. Ten cc. of it are mixed 
 with five cc. of alcohol, and the standard solution is 
 allowed to flow into it, drop by drop, from a burette. As 
 an indicator, he uses slips of filter paper steeped in a mixed 
 solution of perchloride of iron and copperas. From time 
 to time a drop is placed on a little square filter-paper, and 
 allowed to pass through this upon the iron paper. The 
 reaction is complete when a drop no longer blackens 
 this paper. 
 
104 LEATHER MANUFACTURE. 
 
 Standard Method. International Association of 
 Leather Trades' Chemists. — There are few substances 
 which present so many difficulties in the way of their 
 accurate estimation as tannin. Although the subject of 
 the accurate determination of the amount of tannin in 
 any given substance has received the attention of chemists 
 for a great number of years, it must be confessed that no 
 absolutely reliable method has yet been discovered. 
 
 One of the chief difficulties in dealing with tannin is 
 its high molecular constitution, which permits of its being 
 decomposed very readily, forming fresh compounds which 
 introduce further complications into the proper estima- 
 tion of the original tannin. One of the earliest methods 
 of estimating tannin was to precipitate the tannin with 
 a standard solution of gelatine ; but this and other 
 methods involving the use of gelatine were found to be 
 only approximate in their results, and not sufficiently 
 reliable for employment in commercial analyses. It 
 would occupy too great a space even to mention the 
 many different processes, gravimetric and volumetric, 
 which have been tried, without success, to solve this 
 problem. Some methods which are satisfactory with one 
 particular tannin material utterly fail when dealing with 
 another of a different class. It is obvious that some 
 means of estimating tannin had to be employed, and, in 
 consequence, chemists adopted methods of tannin analyses 
 which their own fancy dictated, the result being that 
 great discrepancies in the percentage of tannin in the 
 same sample occurred when analysed by two different 
 chemists. 
 
 As the subject of tannin analyses grew in importance, 
 it became imperative that a standard method should be 
 devised to be employed in all tannin estimations, which 
 would at least procure concordant results, if not accurate 
 determinations of tannin. With a view to establishing 
 such a method, a conference of those principally interested 
 was called in London in 1897, the result of which con- 
 ference was the formation of an International Association 
 of Leather Trades' Chemists, who agreed to adopt one 
 
ESTIMATION OF TANNIN. 105 
 
 "standard" method in all tannin estimations. The 
 method which was agreed upon is known as the " hide- 
 powder filter method ;" but at the annual meeting of the 
 association, additions to and alterations in the originally 
 adopted method are constantly being made. The hide- 
 powder filter method consists in detanizing the tannin 
 solution by means of hide powder placed in a "bell 
 form" of filter through which it is syphoned. The 
 method is carried out as follows : First, the infusion 
 of the tannin material, or the solution of extract (the 
 strength of these depends on the material under ex- 
 aminatidh, an infusion is usually made with between 20 
 to 40 grms. of the material, according to its richness in 
 tannin. An extract solution is made between 12 to 20 grms. 
 of extract. In both cases 1 litre of the liquor is made), 
 is filtered through what is known as the "candle" filter, 
 which is used largely in bacteriological laboratories. The 
 vacuum pump is used to facilitate this filtration, the object 
 of which is to get rid of all insoluble matter. 
 
 It is usual to filter only about half of the litre, the 
 whole having been previously well shaken. 50 c.c. of 
 the clear filtrate is taken for the estimation of the " total 
 soluble" matter. This is done by evaporating to dryness 
 in a weighed porcelain basin on a water-bath, and the 
 residue is afterwards dried in an air oven at about 105° C, 
 then cooled in a desiccator and weighed. A vacuum oven 
 is preferable for drying the residue, as it lessens the ten- 
 dency of the tannin matters to oxidise, thereby gaining 
 in weight. 
 
 The "total soluble" residue contains both tannin and 
 non-tannin matters, so that it becomes necessary to 
 separate them in order to estimate either the " tannin " 
 or the " non-tannin." This separation is carried out on 
 a fresh portion of the solution. The standard method 
 consists in absorbing the tannin matters present in the 
 liquor by means of the hide-powder filter already referred 
 to ; and regarding the filtrate (which has become de- 
 colourised in passing through the hide powder) as contain- 
 ing non-tannin matters, a measured quantity is taken, 
 
106 LEATHER MANUFACTURE. 
 
 usually 50 c.c. The first 30 c.c. from the filter is rejected 
 as containing soluble matter from the hide powder, and 
 the second 50 c.c. is evaporated to dryness in a weighed 
 porcelain basin, and treated exactly as in the case of the esti- 
 mation of the total soluble matters. The difference in the 
 weight between the total soluble residue and the non- 
 tannin residue represents the amount of tannin in 50 c.c. of 
 the original tannin solution, and by a simple calculation 
 the percentage of tannin matter in the original extract or 
 tannin material can easily be determined. The water 
 contained in a tannin extract is determined by drying 
 a weighed quantity of the extract at 110° C, and weigh- 
 ing and drying alternately until the weight is found to 
 be constant. The residue from the moisture determina- 
 tion is termed the "total dry matter." The difference 
 in the weights between the total dry matter and the 
 total soluble matter represents what is termed " insoluble 
 at 15° C." 
 
 It will be observed from the foregoing that the standard 
 method of tannin estimation possesses only moderate 
 claims to scientific accuracy, and differences in manipula- 
 tion affect the final results. For instance, the particular 
 manner in which the hide powder is packed in the bell 
 filter has an important bearing on the results. 
 
 There are many modifications of the hide-powder filter 
 method, such as the American " shake " method, which 
 consists in treating a definite volume of the clear tannin 
 solution with a weighed quantity of hide powder in a 
 glass tumbler, and the mixture is well shaken at frequent 
 intervals in a machine constructed for the purpose. The 
 mixture is afterwards filtered through an ordinary funnel 
 having a plug of cotton wool in the neck, when the fil- 
 trate is found to be completely detanised. In other 
 respects the process is the same as that already described. 
 
 The most unsatisfactory feature in all the methods 
 where hide powder is employed is the difficulty of obtain- 
 ing a regular supply of hide powder of the same quality. 
 Experiments are being made with chrome hide powder 
 prepared from chrome tanned hides, and the results are 
 
ESTIMATION OP TANNIN. 107 
 
 said to be more uniform than those obtained with the 
 ordinary hide powder. 
 
 In conclusion, it is to be feared that the chemistry of 
 the tannins is not yet fully understood, and when more 
 light is thrown upon their chemical constitution, doubtless 
 more scientific methods of analyses will be devised. 
 
CHAPTER IX. 
 PREL1MINAR Y OPERA TIONS. 
 
 Treatment of Green or Fresh Hides. — Method of Salting Hides. — Cleans- 
 ing the Eaw Hides. — Dried Hides. — Softening Dried Hides. — Brain's 
 Process. — Dry Salted Hides. — "Wet Salted Hides.— Schultz's Views 
 on the Treatment of Hides. 
 
 Preliminary Operations. — Since the condition of the raw 
 hides, as they are received by the tanner, influences their 
 preparatory manipulation, it will be necessary to consider 
 them under the three different heads which indicate their 
 condition, namely : 1. Green, or Fresh Hides ; 2. Dried 
 Hides ; 3. Dry Salted Hides ; 4. Wet Salted Hides. The 
 first embraces those hides which are furnished by the 
 slaughter-houses and butchers, and the latter such as are 
 imported from different parts of the world. 
 
 Treatment of Green, or Fresh Hides. — Those hides 
 which have been recently taken from the slaughtered 
 animal require but little labour to cleanse from the ordi- 
 nary " muck " which commonly adheres to them ; since 
 the hides are sold by weight, however, it has sometimes 
 been the practice of unfair vendors to augment their 
 weight by purposely saturating them with such filthy 
 matter. 
 
 It occasionally happens that the green hides of the 
 slaughter-house cannot be at once used by the tanner, in 
 which case, especially in warm weather, the hides are 
 salted, so as to check putrefaction. For example, if the 
 hides are required to remain in stock for a week before 
 undergoing the preliminary process of washing and liming, 
 about four or five pounds of coarse salt are spread over 
 
PRELIMINARY OPERATIONS. 109 
 
 eacli hide ; but if they have to be kept for a longer period 
 about twice that quantity of salt is used. Imported 
 hides, as those from South America, are treated with 
 a still greater quantity of salt, sometimes as much as 
 20 lbs. being used for each hide, according to the size 
 and the season, the average quantity being about 15 lbs. 
 per hide. 
 
 Method of Salting Hides. — The Continental system of 
 salting hides, known as Delande's method, consists in 
 spreading the hides open upon the ground and sprinkling 
 the flesh side with salt, but more liberally at the edges and 
 along tKe spinal parts. The hides are then folded or 
 doubled lengthwise down the centre ; the remaining folds 
 are made over each other, commencing with the shanks ; 
 next the peak of the belly upon the back ; afterwards the 
 head upon the tail part, and the tail part upon the head, 
 and lastly doubling the whole with a final fold, and forming 
 a square [or cushion] of about two feet. This being done, 
 they are piled three or four together, and left until the 
 salt has dissolved and penetrated their tissue, which is 
 generally in about three or four days. Thus prepared 
 they are sent to market. Skins may be dried, even after 
 having been salted, by stretching them upon poles with 
 the flesh side outwards, and exposing them to dry air in a 
 shady place. Ten pounds of salt in summer, and some- 
 what less in winter, are requisite for each skin of ordinary 
 size. — Dassauce. 
 
 Cleansing the Raw Hides. — It is of considerable im- 
 portance that the hides, before being submitted to the 
 several operations which constitute the tanning process, 
 should be freed from all adhering foul matter, blood, &c. ; 
 in short, the hide should be clean. This is effected after 
 the horns are removed by first steeping them in water for 
 several hours — from one to twelve hours, according to 
 their condition — and afterwards removing all the filth thus 
 softened or loosened by washing in clean water, a run- 
 ning stream, where practical, being preferable. When 
 the hides are more than ordinarily dirty they must be 
 removed from the soaking bath and scraped with a blunt 
 
no LEATHER MANUFACTURE. 
 
 tool, Fig. 5, on the beam, trampled upon in water, and 
 finally well rinsed. When a running stream is available 
 it is considered a good plan to secure 
 the hides to a rack, and this being 
 fixed in the full force of the stream, 
 Fig- 5 - the friction of the water loosens and 
 
 dislodges the objectionable matter, whereby there is a 
 considerable saving of labour. 
 
 Dried Hides. — It will be readily understood that skins 
 which have been deprived of their natural moisture by ex- 
 posure to the air or the heat of the sun, without under- 
 going any further treatment, for export purposes, merely 
 require to have the moisture they had lost in drying 
 restored to them to bring them to the condition of green 
 or fresh hides. And this is so in fact ; but in order to 
 facilitate the absorption of moisture by the indurated or 
 hardened surfaces of the hides without wasting their sub- 
 stance, a certain amount of mechanical treatment is neces- 
 sary. If the skins could be soaked in boiling water they 
 would very soon recover their normal condition ; but as 
 gelatine is soluble in hot water, the skins, by such treat- 
 ment, would not only lose considerably in weight, but their 
 porous structure — so important to the free absorption of 
 tannin — would become altered, if not destroyed. Dried 
 skins, therefore, must be brought to a pliant state by cold 
 soaking in the first instance, and by subsequent beating, 
 rubbing, and soaking to render them supple. 
 
 Softening Dried Hides. — The dried" or " flint " hides 
 of Buenos Ayres, River Plate, and other localities, are first 
 thrown into cold water, in which they are soaked from ten 
 to fourteen days, according to their thickness ; but after 
 being in soak for several days they are subjected to mecha- 
 nical treatment by being forcibly rubbed or " broken " with 
 the blunt tool on the beam, after which they are again 
 soaked and then subjected to a process of beating, which in 
 most establishments is effected by a machine called ihe 
 fulling stocks, which, by repeated blows of the hammer or 
 toes upon the partially softened skin, alternated by further 
 soakings, eventually reduces the hides to nearly the con- 
 
PRELIMINARY OPERATIONS. 
 
 in 
 
 dition of fresh hides. An illustration of such a machine, 
 as made by Huxham and Browns, is shown in Fig. 6. 
 
 Fig. 6. 
 
 Brain's Process. — A process for softening 1 dry hides 
 and puring skins from lime has been introduced bj* - Mr. T. 
 Brain, which appears to have commanded some attention 
 from the trade. In an address to the Scottish tanners, he 
 said, " I have succeeded in making a compound not only 
 inoffensive, but emitting a pleasant odour, which I shall 
 be prepared to sell under a registered title, and which for 
 dressing leather is applicable with a little alteration in 
 the use, and washing through clean cold water afterwards, 
 
 with careful scudding Tanning of dressed leather 
 
 prepared by my process does not require the liquor to be 
 so strong or new at commencement as skins require by 
 the bating or reducing system generally in use. By the 
 old way the pelts have parted with so much gelatine that 
 if they are put into very weak liquor they go on losing 
 gelatine. But by using a moderately strong liquor for 
 a day or two it closes the extremities of the fibrine, con- 
 sequently the gelatine ceases to flow out, and they are put 
 
U2 LEATHER MANUFACTURE. 
 
 into a weak liquor to ' recover breath.' By puring the 
 pelt from lime and not reducing by bate, it retains all the 
 gelatine, and should be well handled in a weak stale liquor 
 for a day, and then shifted to increased strength daily, so 
 that a gain of about 1 per cent, is kept up additionally, 
 commencing at about 6 degrees for dressing and 10 de- 
 grees for sole." 
 
 Dry Salted Hides, as those from Texas, Pernambuco, 
 &c, are treated much in the same way as dry hides, but 
 are somewhat more readily softened than what are called 
 " flint " hides. 
 
 Wet Salted Hides are soaked in water to remove the 
 saline matter, after which they are rubbed on the beam 
 and again soaked, until they are in the proper condition 
 for the lime-pits. 
 
 Schultz's Views on the Treatment of Hides.* — " In 
 all the processes, commencing with the soaking and mill- 
 ing or wheeling, through the lime or bate, each pelt must 
 be individually treated ; and if the conditions are much 
 varied, more judgment and care will be necessary in their 
 treatment as a whole than if they are substantially alike. 
 In the latter case ordinary intelligence would suffice to 
 perform creditable work. This degree of intelligence is all 
 that the employer has a right to expect, and hence the 
 importance of making as light drafts upon the brain power 
 of his men as possible, by making the labour uniform on 
 each piece of stock. How few calf- skin tanners in this 
 country [America] think it important to classify their 
 skins ! Do they not work all skins, from six pounds to 
 twelve, in the same pack ? Whatever is classed as 'veal' go 
 together ; the first selection that is thought of is when the 
 finishers are wanting stock. The packs are then assorted, 
 and the tanned skins are selected out and sent to the cur- 
 rying shop, while the heavy ones are given another liquor. 
 This is beginning at the wrong end : the selection should 
 have taken place before the skins entered the beam house, 
 when the advantages of classification would have been 
 secured all the way through the process. 
 
 * " Leather Manufacture." By Jackson S. Schultz. 
 
PRELIMINARY OPERATIONS. "3 
 
 " In a well-regulated calf or kip-skin yard, from the 
 time the skins enter the tannery they are mated (for 
 reasons hereafter stated), and continue this connection 
 through the whole after tanning process. But how can 
 dissimilar sizes and substances be suitably paired, and so 
 placed, grain to graiD, as to fully cover each other ? What 
 has been said thus far goes to the advantage of the intrinsic 
 quality of the stock ; but suppose some hides or skins are 
 damaged, or partially so ? These should by no means be 
 allowed to contaminate the good. They are the sick mem- 
 bers, and must be placed in hospital under observation. 
 They may not all have the same disease, and must be 
 placed in different ' wards ' or apartments for special 
 treatment. When one thinks of the indiscriminate and 
 forcing processes which valuable stock receives at the 
 hands of many tanners, the inhumanity of the treat- 
 ment is forced on one's mind. Sick or well, strong or 
 weak, large or small, the same methods, the same trying 
 ordeal, must be passed by all, and that so few should break 
 and fail is a wonder. 
 
 "It remains only for me to say a word about the im- 
 policy of working a variety of hides in the same yard. It 
 is not to be denied that some tanners succeed in making 
 good stock out of a variety of hides under treatment at the 
 same time ; but this is the exception, and should not be 
 ventured upon by the average tanner. At least one sea- 
 son's or one year's hides should be of one kind, or as 
 nearly so as possible. Buenos Ayres, Monte Yideo, and 
 Rio Grande are sufficiently alike to be classed together. 
 Central America and Matamoras, and even dry Texas, are 
 possibly similarly conditioned. California and Western 
 may be well treated as similar hides, requiring light treat- 
 ment ; but there cannot be safely treated dry salted and 
 dry flint hides in the same beam house ; lime and sweat 
 stock cannot go through together without danger, or cer- 
 tainly with the hope of the most satisfactory results. The 
 best leather is made by tanners who work a uniform de- 
 scription of hide. This is the usual experience, and is 
 based on common sense." 
 
H4 LEATHER MANUFACTURE. 
 
 These observations, emanating as they do from one of 
 the most experienced and observant of American tanners, 
 deserve the fullest consideration, and few, we should 
 imagine, will question their wisdom. Of all the members 
 of the trade in any country, Jackson Schultz will ever be 
 held in esteem for his generous desire to promote the wel- 
 fare of his trade by freely and ungrudgingly making 
 known the results of his own vast personal experience for 
 the benefit even of his competitors — an attribute but sel- 
 dom, and it must be acknowledged with regret, found in 
 those who follow the art of tanning in this country. 
 Indeed, the reticence, " closeness," or so-called " conserva- 
 tism " of the tanning trade in this country are, we think, 
 to be deplored ; for were the followers of this great art to 
 assist each other by the interchange of ideas, and by making- 
 known such modifications of processes as may from time 
 to time have proved successful, not only individuals, but 
 the whole fraternity, as well as the general public, would 
 be the gainers. 
 
CHAPTER X. 
 
 D EPILATION, OR TINE AIRING SKINS AND HIDES. 
 
 Depilation by Lime. — Properties of Lime. — Storing the Lime. — Liming. — 
 Single Pit Method. — Working in Bounds.— Continental Method of 
 Liming. — Supposed Disadvantages of the Lime Process. — Dr. Davy 
 on the Action of Lime on Animal Matter. — Working on the Beam. — 
 Rounding the Pelts. — Depilation by Sweating. — Cold Sweating. — De- 
 pilation by Acids. — Depilation by Saccharine Matter. — Depilation by 
 Caustic Soda. — Depilation by Bisulphide of Calcium. — Depilation by 
 Charcoal. — Depilation by Sulphide of Sodium. — Palmer's Process. — 
 Beck's Process. — The Pullman-Payne Process. 
 
 Depilation by Lime. — The removal of the hair from 
 skins and hides, called depilation, or unlmiHng, and which 
 may also be termed dehairing, is performed by several 
 different processes, bnt that which rinds most favour in 
 this country is that known as the lime process. When a 
 fresh skin is allowed to remain for a certain length of time 
 in a mixture of caustic (that is fresh) lime and water, the 
 cuticle or epidermis, together with its hair, readily sepa- 
 rates from the cutis or true skin, while at the same time 
 the fatty and fleshy matters of the under portion of the 
 skin become easily separable by the operations of the 
 fleshing knife. During the soaking in the lime-pits, the 
 fatty matters become partially converted into an in- 
 soluble lime soap, whereby the fleshy portions are loosened 
 and may be readily scraped from the under surface of the 
 true skin. 
 
 Depilation by lime is the oldest method known, and 
 although it possesses certain disadvantages, it is still more 
 extensively adopted than any other method of unhairing. 
 The lime is made into what is called milk of lime, by 
 
u6 LEATHER MANUFACTURE. 
 
 mixing recently slaked lime with water in varied prc-por- 
 tions, the weakest mixture being that in which the hides 
 are first soaked, and in which they are allowed to remain 
 for one or two days, after which they are transferred 
 to another pit containing a stronger lime mixture, and so 
 on, through successive steeps of increasing strength until 
 the scarf skin, with its hair, readily yields to the touch, 
 which is generally the case in from two to three weeks, 
 according to the texture and condition of the hides and 
 the temperature of the atmosphere. As in all other tanning 
 processes, however, there is a great diversity of opinion ; 
 whether the process of liming should be conducted slowly 
 in weak liquors, or as quickly as possible in strong 
 liquors, is yet an open question. The old tanners used 
 to employ very weak liquors, in which the process of depi- 
 lation occupied seA^eral — sometimes many — months for its 
 completion. Now, however, we have been taught to believe 
 that so long a soaking as even three weeks causes a loss of 
 gelatine ; some tanners, therefore, prefer using strong 
 liquors, whereby they are enabled to unhair the hides even 
 in so short a time as about seven days ; and indeed from the 
 very nature of the operation — that of removing the cuticle 
 and hair chiefly — this method of depilation would appear 
 not only the most scientific, but also the most practical, if 
 conducted with great care. It is found also that the 
 pelts, after treatment in the strong limes, are swollen to 
 their fullest extent, and that, after tanning, they give 
 greater weight than those which have been treated for a 
 longer period in weaker lime liquors. When we reflect 
 that the loosening of the epidermis on the one side of 
 the skin and the fleshy matters on the other are the 
 objects of liming, if this can be effected in such a way 
 that the true skin is not subjected to any action of the 
 lime it will undoubtedly be an advantage, since the rais- 
 ing or swelling can be effected by less objectionable or 
 more suitable materials than lime. The nearest approach 
 to a perfect system of liming would appear to be that 
 which is quickest, for in this case the gelatine of the 
 skin is less liable to be dissolved than when subjected 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 117 
 
 for a lengthened period in weak liquor. It almost appears 
 contrary to principle to steep hides in spent or weak 
 lime at all. 
 
 Properties of Lime. — Before giving the various pro- 
 portions of lime employed by different manufacturers, it 
 may be well to consider what is the nature of lime and to 
 what extent it is soluble in water. "When chalk or lime- 
 stone (carbonate of lime) are calcined at a high tempera- 
 ture, water and carbonic acid gas are expelled, and oxide 
 of calcium, or lime, remains behind. If this lime be again 
 exposed to the air, it readily attracts carbonic acid, and 
 again becomes converted into carbonate of lime, and 
 assumes the form of a white powder. If a lump of fresh 
 lime be sprinkled with water, in a few moments a hissing 
 and crackling sound is heard, the lime sj)lits up in all 
 directions, with evolution of steam, the heat engendered 
 being so great as to be capable of igniting wood. The 
 lime absorbs about 31"0 of its weight of water, and falls 
 into a dry, white powder called hydrate of lime — a chemical 
 compound of oxide of calcium (lime) and water. It 
 is an ascertained but remarkable fact, discovered by 
 Dalton, that lime is more soluble in cold than in hot 
 water ; that is to say, water at 60° Fahr. dissolves yfg-, 
 while at the temperature of 212° Fahr. (the boiling-point 
 of water) it only takes up x .J 7 6 . Mr. E,. Phillips ascer- 
 tained that water near the freezing-point took up about 
 one-seventh more than water at 60° Fahr., and nearly 
 double that of boiling water. 
 
 The solubility of lime at the several temperatures is as 
 follows : — 
 
 A pint of water at 32° Fahr. dissolves 13 '25 grains of lime. 
 „ „ 60 „ „ 11-6 „ „ 
 
 From this it will be seen that in cold weather the 
 strength of the lime liquors (if an excess of undissolved 
 lime be present in the lime-pits) will be greater than in 
 hot weather. Since, however, chemical action is always 
 more vigorous in warm than in cold temperatures, the 
 
H8 LEATHER MANUFACTURE. 
 
 weaker solutions of lime would be fully as active in sum- 
 mer as the stronger liquors in cold weather ; doubtless 
 the colder temperatures, however, would be less injurious 
 to the pelt. 
 
 As to the proportion of lime which should be employed 
 for fifty hides, there seems to be great diversity of opinion. 
 While some manufacturers use from 2i to 3 bushels for 
 each pit, others have been known to employ more than 
 twice as much. About 2 lbs. of lime for each hide is con- 
 sidered a good proportion. 
 
 Storing the Lime. — Bearing in mind that lime deterio- 
 rates by absorption of carbonic acid from the air, it 
 requires to be protected from its influence as much as pos- 
 sible. The lime should be kept in a dry closed shed, away 
 from contact with timber ; and in order to protect the 
 bulk from the air, it is sometimes the practice to sprinkle 
 the pile with a little water, to slake the lime on the 
 exterior surface, which falls to a powder and acts as a 
 covering to the rest of the heap. Another method of 
 treating the lime is to place it in a large pit and to slaken 
 it with water, and then to cover the whole with a small 
 quantity of water, finally covering up the pit with hurdles 
 and matting. The thick paste of caustic lime thus formed is 
 taken out by shovelfuls at a time as required, and the pit 
 again closed. In this way lime is said to be preserved in 
 a caustic state for a considerable time, which would doubt- 
 less be the case. 
 
 Liming. — There are two methods in practice for carrying 
 out the process of liming, namely, 1. The Single Pit Method; 
 and, 2. Working in Rounds. In the former, the same pack 
 of hides is treated in a single pit, with additions of fresh 
 lime from time to time, and in the second the hides are 
 first placed in a weak lime or old lime liquor, and suc- 
 cessively steeped in stronger liquors, until the epidermis 
 yields to the touch. 
 
 Single Pit Method. — The complement of lime and water 
 being introduced into the pit, the hides are immersed one 
 by one, care being taken to spread them out as flat as 
 possible, until the entire number is immersed. After three 
 
DEPILATION, OR UNHAIRING SKINS AND HIDES. 119 
 
 or four hours they are handled or removed from the pit, 
 being piled one over another in a heap, after which they 
 are then returned to the pit as before ; after a few hours 
 they are subjected to a second handling on the first day. 
 The handling is effected by means of blunt-pointed hooks 
 (Fig. 7). On the second day, the hides are again drawn, 
 
 Pig. 7. 
 
 and allowed to remain in a heap as before for an hour or 
 so, during which time the lime at the bottom of the pit is 
 gently stirred or plunged, and the hides are again placed 
 in the pit. They are subjected to this treatment during 
 the first three or four days, by which time they will have 
 become considerably swollen. They are now again drawn 
 and placed in a heap as before, and a fresh quantity 
 of slaked lime is added and stirred up with the lime 
 already in the pit ; the hides are again immersed, and 
 the handling and stirring of the liquor repeated once a 
 day until the expiration of about twelve or fourteen days 
 from the commencement, by which time they will gene- 
 rally be in a condition for unhairing. The same lime 
 liquors, with additions of fresh lime periodically, may 
 be used several times, or until the liquors give indications 
 of being charged with ammonia, when the pits must be 
 cleaned out. 
 
 Working in Rounds. — This method is much adopted by 
 some tanners, and consists in working a series of pits con- 
 taining lime liquor of different degrees of strength. The 
 green or fresh hides are taken from the water-pits and 
 immersed in the old or spent lime-pit, being handled as 
 before ; and from this pit they are shifted to the next or 
 stronger lime, and so on until they have passed through 
 the whole series of three or four pits. Each of these pits 
 being strengthened by fresh additions of lime, the last pit 
 becomes the first in the next round, and so on until the 
 liquors become surcharged with ammonia, when they are 
 
t2o LEATHER MANUFACTURE. 
 
 cleaned out and recharged with fresh liquor. When this 
 system is adopted it is necessary to employ pits close to 
 each other to save unnecessary labour. 
 
 Continental Method of Liming. — The method of liming, 
 as practised on the Continent, is thus given by Dussauce : 
 " In some parts, as in France and Belgium, well-bound 
 tubs are preferred. The number of these varies from five 
 to twelve, and the solution is then so arranged that there 
 is a regular increasing gradation of" density from the first 
 to the last, even where the greatest number is taken advan- 
 tage of. The first of these, usually called the dead vat, 
 contains very little caustic lime, and this is the one to 
 which the hides, after washing, are exposed in commencing 
 the operation. Here they remain from one to three days, 
 according to circumstances, and during this period they 
 receive a handling at regular intervals, some twice and 
 
 others three times a day Before the reintroduction, 
 
 the contents of the vat are well agitated, with a view to 
 distribute any undissolved quicklime through the liquid, 
 so that there be no partial or undue effect exercised on the 
 skins. The workmen likewise contrive to spread out the 
 latter in the vat as much as possible, and so every part has 
 the same exposure to the lime. In the dead vat, however, 
 there is very little if any quicklime undissolved. After 
 remaining the allotted time in the first vat they are trans- 
 ferred to the second, which contains a stronger liquid, or 
 more lime, and left in this, with occasional overhauling, 
 for a few days, after which they are put into the third, 
 and so on, till the hides ultimately arrive at the last vat, 
 which contains the fresh lime. In operating in this rota- 
 tion, the dead vat of one batch of hides becomes the live 
 one of the next, and so on in succession. The time which 
 skins take for thorough liming varies according to their 
 weight and texture. Thus the lighter skins, as of the 
 sheep, are sufficiently acted upon in three to five days, but 
 ox hides, kips, and calf-skins require two to three weeks, 
 according to the season In many parts of the Con- 
 tinent, however, the operations preparatory and conductive 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 121 
 
 to the depilation last two or three months, but in these 
 cases the skins are partly swelled, so that, for this special 
 treatment, they do not require so much attention in the 
 succeeding stages. The quantity of lime which is used by 
 the different tanners is somewhat various, and dependent 
 upon the size of the hides, but the average is from 18 to 
 24 gallons of freshly burnt fat lime — 3 to 4 cubic feet 
 measure — for 100 hides of average size." Sometimes hides 
 are limed by suspending them from poles in a deep lime- 
 pit, whereby considerable time is said to be saved and 
 much less handling required. 
 
 Supposed Disadvantages of the Lime Process. — While 
 the process of liming hides and skins possesses the advan- 
 tages of simplicity and economy, on the other hand, in the 
 opinions of some persons, it presents many important dis- 
 advantages, which render its employment objectionable. 
 This view is held more especially on the Continent. The 
 action of the lime is stated to cause a portion of the mem- 
 branous matter of the skin — which, were it not removed, 
 would enter into the substance of the leather — to be dis- 
 solved, whereby a certain loss is sustained. Again, liming 
 renders t'he surface of the hide unequal, and by entering 
 the cellular structure of the skin, retards the action of the 
 tan and causes it to act ununiformly. That this latter 
 effect is produced there is no doubt whatever, but as to the 
 former, the researches of Dr. John Davy,* conducted at 
 Malta in 1829, prove that lime has no injurious action 
 upon animal tissues. 
 
 Dr. Davy on the Action of Lime on Animal Matter. — 
 " It is commonly asserted and believed that lime exercises a 
 corroding, destructive influence on animal matter in general, 
 and that animal bodies exposed to its action rapidly de- 
 compose and disappear. Accordingly, it has been almost 
 invariably recommended to add this earth to graves in 
 instances in which rapid decay is considered desirable, as 
 on the occasion of the crowding of grave- pits with dead 
 bodies during the prevalence of pestilential diseases. From 
 * The Chemist, vol. i. New Series, p. 227. 
 
122 LEATHER MANUFACTURE. 
 
 the results of many experiments which I have made with 
 lime on animal substances, I have been compelled to come 
 to the conclusion that this opinion is not well founded in 
 fact ; indeed, that it is altogether erroneous. The experi- 
 ments were commenced in Malta in the summer of 1829, 
 and they were carried on during the following year. The 
 method observed was to immerse the animal matter for 
 trial in cream of lime, or rather a paste of lime, contained 
 in a wide-mouthed bottle, well corked and covered with 
 cerate cloth to exclude ingress of atmospheric air and to 
 preserve the lime in its caustic state. One of the first 
 experiments tried commenced on the 27th of August. 
 Portions of various textures were immersed, as mentioned 
 above. They were taken from a subject in a state of 
 incipient putrefaction, and they exhaled a fetid smell. On 
 immersion in the lime and water, as might be expected, 
 they gave off a strong ammoniacal odour. They were 
 first examined on the 24th of September ; they were then 
 all in excellent preservation, swollen, but not corroded 
 nor their delicate tissue injured." At the expiration 
 of seven months, namely in the May following, the 
 animal substances were again examined, and were found 
 to be much in the same state as before, "the texture 
 of each part distinct, and the part, as a whole, easily 
 distinguishable." After being left undisturbed for nearly 
 two years they were again examined, when considerable 
 change had taken place ; the cuticle had become soft 
 and transparent, and many other parts had become un- 
 distinguishable. 
 
 In a second experiment, " commenced in the beginning 
 of October, portions of skin, intestine, cellular tissue, 
 muscle, tendon, &c, were similarly treated. The results 
 were examined on the 5th of May following. Then, on 
 opening the bottle, an ammoniacal, but not putrid, smell 
 was perceptible. The parts were found well preserved, 
 excepting the fatty matter contained in the cellular tissue, 
 which had become opaque, white, and friable, from com- 
 bination with the alkaline earth and conversion into soap. 
 The tendon was somewhat distended and rendered more 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 123 
 
 transparent, but not gelatinised ; and so also the cutis, the 
 last being deprived of its cuticle and hair." Dr. Davy 
 found that " after animal substances have been subjected 
 to the action of lime, they ceased to be putrescent ; they 
 resisted putrefaction, whether placed in air or plunged and 
 
 kept in common water A portion of the cutis 
 
 similarly treated, placed in confined air in a bottle, after a 
 whole month emitted no unpleasant odour and appeared to 
 be unchanged. I have observed," continues Dr. Davy, 
 " that the cuticle, nail, and perhaps hair, are to be excluded 
 from the list of animal substances not materially altered 
 by the action of lime. On the cuticle its action is power- 
 ful, and, I apprehend, in consequence of a chemical com- 
 bination between them being formed." 
 
 Dr. Davy finally arrives at this conclusion, as the result 
 of a great number of experiments : — " That lime does not 
 exercise a destructive corroding power on animal substances 
 generally, nor one promoting their decomposition, but on 
 the contrary, a preservative and decidedly antiseptic 
 power, arresting putrefaction even when commenced, and 
 retarding decomposition." 
 
 From the foregoing observations, based upon a series of 
 experiments conducted with great care during a period of 
 several years, it would appear that however objectionable 
 the presence of lime may be if not carefully eliminated by 
 bating, by dilute acids, or other means, it has no injurious 
 effect upon the cutis vera, or true skin, which, when tanned, 
 constitutes leather. Assuming Dr. Davy's deductions to 
 be correct, the hypothesis that the liming process, fairly 
 conducted, reduces the weight of the hides by acting upon 
 and dissolving a portion of the gelatinous tissue of the 
 pelt, must be fallacious. It is easy to understand that after 
 several weeks' immersion in the lime-pit the fatty matters 
 of the hide enter into combination with the lime, forming 
 a lime soap, and that the cuticle and even the hair will 
 yield to the action of the lime; but from Dr. Davy's obser- 
 vations it would appear that the true skin, or pelt, would 
 undergo no change whatever in the milk of lime mixture 
 in which the hides are by custom immersed. The same 
 
124 
 
 LEATHER MANUFACTURE. 
 
 cannot, however, be said in respect of hides which are 
 steeped for several days in spent or very weak liquors, 
 since the solvent action of the water upon the gelatine of 
 the hide in these cases would be to a great extent unre- 
 stricted. 
 
 Working on the Beam. — When the hides have remained 
 sufficiently long in the lime-pits they are examined, and if 
 the cuticle readily separates when plucked by the fingers, 
 they are taken out and removed to the beam house, where 
 they are submitted to certain mechanical operations by 
 which the scarf skin, with its hair, is removed from the 
 grain side, and the flesh and fatty matter dislodged from 
 the flesh side. These operations are termed respectively 
 unhairing and fleshing. 
 
 Unhairing. — To accomplish this operation the skin is 
 laid upon a convex wooden or iron 
 support called the beam (Fig. 8), 
 with its flesh side inwards, and 
 the beam man then takes a two- 
 
 Fig. 9. 
 
 handled tool, called the unhairing 
 knife (Fig. 9), the blade of which 
 is blunt, and curved to fit the 
 convex surface of the beam. Fig. 10 illustrates the 
 mode in which the unhairing is performed. The hair 
 is removed very easily by pressing the knife downward 
 with moderate force, when the grain of the skin becomes 
 exposed. The operation of unhairing a hide is performed 
 very quickly, one man being capable of unhairing many 
 dozens in a day. 
 
 Fleshing'. — After the hair is removed the hides are fleshed, 
 an operation which requires to be performed with more 
 care and skill than the last operation, because the knife 
 with which it is effected has a sharp edge, and the action 
 of the tool is to cut or shave off the fleshy matters, 
 whereas the unhairing knife, having a blunt edge, merely 
 
DEPUTATION, OR UN HAIRING SKINS AND HIDES. 125 
 
 scrapes or rubs the loosened epidermis from the grain side 
 of the corium or true skin. In using the fleshing- knife 
 
 Fig-. 10. 
 
 (Fig. 11) the workman has to be very careful not to cut 
 away any portion of the true skin, his object being only 
 to remove the fat and flesh, so 
 as to leave the corium fully 
 exposed for the after process 
 of tanning. Fig. 12 illustrates Fig. 11. 
 
 the operation of fleshing. 
 
 After unhairing and fleshing, the pelts, as they are now 
 called, are thoroughly washed and once more scraped with 
 a blunt tool to remove any lime or other matters that may 
 still attach to them. This operation is called scudding. The 
 fleshings, as they are called, are collected and pressed into 
 cakes, and sold to the glue-makers, as also are the ears 
 and all projecting parts, which would be useless when 
 tanned. The hair was formerly used chiefly by plasterers 
 for mixing with mortar, but it is now, after being thoroughly 
 
126 
 
 LEATHER MANUFACTURE. 
 
 washed and cleansed, employed in the manufacture of 
 cheap clothing, blankets, and imitation sealskin. 
 
 It is not always the case that the fleshing is carried out 
 to the fullest extent, leaving nothing but the true skin to 
 be tanned. Some manufacturers prefer to leave a portion 
 of the flesh attached, so that the butts should present a 
 more mottled appearance, while some of the American 
 
 Fisr. 12. 
 
 tanners merely have the flesh side lightly scraped, by 
 which, of course, greater weight is given to the leather. 
 For the finest quality of bark- tanned butts, however, it is 
 essential that nothing but the true skin should enter the 
 tan pit, and since this, being quite free from fleshy matter, 
 is very easily injured, great care is necessary in the 
 handling of the pelts in the earlier stages of the tanning 
 process. 
 
 Bounding the Pelts. — It was formerly the custom to 
 tan the hides whole, after unhairing and fleshing, but the 
 system adopted at the present day is to remove with a 
 sharp knife all the inferior parts of the pelt, and to tan 
 the butts and bends separately. To this end the hide is 
 taken by two men and laid upon a table called the rounding 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 127 
 
 table, it is tlien doubled from end to end, grain side out ; 
 the head is then removed by a cross cut with the rounding 
 knife (Fig. 13) ; the rough edges of 
 the tail end are then cut away or . -^^-^ 
 rounded, and the sides or bellies are ^- — ..-^ JI^be? 
 
 next cut off, either by one cut or Fig. 13. 
 
 separately. By this method, how- 
 ever, the rounder is unable to see those defects, irregu- 
 larities, or brand-marks which may be on the under side, 
 and consequently cannot trim the hide in such a way as 
 to make the best of it. It is, considered a better plan, 
 
 therefore, to lay the hide across^ wooden frame, or horse, 
 supported by trestles, the frame*of which forms a tri- 
 angular arch. The hides being l«fcl across this, the 
 rounder is able to see all parts of the hide, whereby he 
 
128 LEATHER MANUFACTURE. 
 
 is enabled to perform the operation of rounding with more 
 skill and judgment. The accompanying drawing (Fig. 14) 
 illustrates by the dotted lines the course which the rounding 
 knife should take to separate the various parts from the 
 butt, a, or chief part, of the hide, b represents the shoul- 
 der, c c the cheeks, and d d the sides or belly pieces. On 
 glancing at the somewhat irregular form of the expanded 
 hide it will be evident that some judgment must be exer- 
 cised in removing the surrounding parts — which are tech- 
 nically called offal — from the butt, so as to make the most 
 of the latter or more valuable part of the hide. 
 
 After unhairing and fleshing, the hides sometimes pre- 
 sent inequalities as to thickness, and in order to render 
 them more uniform, or of an average thickness through- 
 out, the following plan is adopted, but more especially on 
 the Continent : The hides are rubbed with a smoothing 
 or polishing stone, which is a tool made of sandstone 
 interiorly moulded so as to lie parallel upon the beam, and 
 is fixed to a piece of wood furnished with two handles. 
 With this the hide is rubbed to bring the parts as nearly 
 as possible to an equal thickness. By repeated rubbings 
 or scrapings in this way with the stone, alternated by 
 washings, the dirt, fleshy parts, and lime are removed as 
 far as possible before tanning. 
 
 Depilation by Sweating.— By this method the cuticle 
 and fleshy matters are loosened from the corium by a pro- 
 cess of putrefactive fermentation, or slow decomposition. 
 Although this process is more generally adopted on the 
 Continent than in this country, it is employed by some 
 English tanners, and is in some respects, if carefully con- 
 ducted, preferable to depilation by lime. After removing 
 the horns, the hides are piled in heaps for several days, 
 after which they are laid across poles in a close apartment 
 called a smoke-house, heated somewhat above the ordinary 
 temperature by means of a smouldering fire fed with 
 spent tan, which produces no flame, or by steam heat. 
 In this room the hides undergo a slight superficial fer- 
 mentation, by which the cuticle, with its attached hair, 
 becomes softened. In France one-half of the hide is 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 129 
 
 first sprinkled with salt and the other half lapped over 
 it, to prevent the putrefaction from injuring the tissue 
 of the skin. 
 
 In Germany the hides are first piled in a heap and then 
 covered with spent tan ; in a short time putrefaction sets 
 in, but unless great care is exercised the hides are liable to 
 be injured. Another system is to pile the hides on a bed 
 of litter, then to cover them with litter, and allow them 
 to remain for twenty-four hours, after which they are 
 turned over and examined from time to time to ascertain 
 if they are fit for unhairing. 
 
 Cold Sweating. — In some parts of the United States 
 a system of cold sweating is practised, the hides being 
 exposed to damp air in a close apartment. The air is 
 kept moist by a spray of water, and it is said that in 
 from six to twelve days the hair comes off easily. It 
 is further stated that by this method no putrefaction 
 takes place, but the loosening of the epidermis is due 
 solely to the softening action of the moisture. It is 
 obvious, however, that by the above methods the fatty 
 matters are not in any degree removed (as is the case in 
 the liming process to some extent), consequently these 
 must be dislodged by mechanical means on the beam. 
 The American system of cold sweating is more fully given 
 in another chapter. 
 
 Depilation by Acids. — It has long been known that 
 acid liquors have the power of acting upon the roots of 
 the hair and cuticle, so as to render them easily detached 
 from the true skin. In some tanneries dilute sulphuric acid, 
 pyroligneous acid (wood vinegar), fermented barley, rye, or 
 bran, or sour milk are used, the latter agent being adopted 
 by some Parisian tanners. Rye- water and fermented barley 
 are also sometimes employed after the skins have been 
 limed, as a substitute for bating. Barley or rye meal in a 
 state of fermentation were at one time much used as a 
 steep for loosening the cuticle and hair, the active agent 
 being the acetic acid formed during the decomposition of 
 the vegetable matter. Sulphuric, hydrochloric, and oxalic 
 acids have each in turn been employed to loosen the cuticle 
 
13° LEATHER MANUFACTURE. 
 
 and hair, thereby enabling them to be removed from the 
 true skin by the process of scraping- or working on the 
 beam ; but tanners maintain that by their employment the 
 skins are swelled to such an extent as to injure them 
 materially. 
 
 The weak vegetable acids are not excluded from practice, 
 more especially in France, Belgium, and parts of Germany. 
 Many of the Paris tanners submit the hides, after they 
 have been soaked in water, washed, and fleshed, to a number 
 of acid vats, in a way analogous to the liming. Generally 
 the series of baths consists of five, which from the first to 
 the last increase in power and efficacy. The first is usually 
 intended to cleanse the hides, the second to soften the hair 
 and epidermis for the depilation, and the other three to 
 swell and give body to the skins. This operation, which 
 is called the white dressing, requires a period of five weeks 
 in the summer and six in the winter season. The quantity 
 of farinaceous matter which is taken varies at different 
 establishments — in some cases 145 lbs. of barley-meal, and 
 in others 150 or 160 lbs., are employed. The dressing is 
 generally made by leavening one-tenth or one-fifteenth of 
 the bulk till it becomes sufficiently sour ; it is then softened 
 with hot water, and after the whole has become a thick, 
 homogeneous fluid free from lumps, it is added to the 
 remaining quantity of the meal in the vat, and tepid 
 water in sufficient quantity is poured in to fill the vessel. 
 In some cases yeast is added to quicken the fermentation. 
 Eight or nine hides are worked in each vat, and as in 
 the lime process, the weak or first vat passes in succession 
 from one to the other in rotation. The final vat is com- 
 pounded of 60 lbs. of meal leavened and thinned with 
 water, and left to develop acetic acid for fifteen days. 
 In all of these operations, handling and working the 
 hides on the beam at regular intervals are indispensable. 
 — Dussauce. 
 
 Depilation by Saccharine Matter. — In 1844 Dr. Turn- 
 bull obtained a patent for the employment of sugar as a 
 depilatory. A solution is prepared by dissolving 14 lbs. of 
 coarse sugar in 100 gallons of water, in which the skins 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 131 
 
 are immersed and allowed to remain for eight or ten days, 
 being handled in the usual way daily. As soon as the 
 hides are sufficiently raised they are removed from the 
 sugar steep and allowed to drain, after which they are 
 immersed in a strong solution of sea salt, which causes the 
 epidermis to contract and become readily detached from 
 the true skin. After washing in clean water the hide is 
 ready for the tan-pit. It does not appear that this process 
 has received much attention, but there is much in its 
 favour — more especially at the present day, when sugar is 
 very cheap — to merit reconsideration. 
 
 Depilation by Caustic Soda. — This powerful alkali has 
 sometimes been employed for unhairing skins and cleansing 
 the flesh side from fatty and fleshy matters, which it is 
 capable of doing with great rapidity, but extreme caution 
 must be exercised in its employment. In order to ensure 
 the uniform action of the caustic liquor it is recommended 
 either to suspend the hides in the solution or to continually 
 handle them while in the pit, otherwise the thinner parts 
 of the skin at the edges will be acted upon by the caustic 
 liquor while the bulk of the hide may be but little affected. 
 The caustic soda is prepared by adding recently slaked lime 
 to a boiling solution of ordinary soda crystals in water, 
 with brisk stirring. After a few hours' repose the car- 
 bonate of lime forms deposits at the bottom of the vessel, 
 Avhen the clear solution of caustic soda may be drawn off 
 for use.* The solution freely enters into combination with 
 the fatty matters of the hide, converting them into soap, 
 which may be recovered from the bath or pit when the 
 liquor has lost its causticity by adding sulphuric acid to 
 the liquor; this, combining with the soda of the soapy 
 solution, will set the fatty matters free, which after a 
 while will rise to the surface, and may be skimmed off and 
 kept in casks for the use of soapmakers. Although caustic 
 soda as a depilatory has not been much used in England, 
 it is very questionable whether it does not deserve more 
 consideration than has hitherto been bestowed upon it. 
 
 * Caustic soda may be obtained in the solid state, as supplied to soap- 
 makers, &c, thereby saving the trouble of preparing it. 
 
*3 2 LEATHER MANUFACTURE. 
 
 Depilation by Bisulphide of Calcium. — This compound 
 of sulphur and lime, commonly called sulphuret of lime, in 
 the form of a paste, has been employed as a depilatory for 
 skins and hides, and if carefully applied is very effective 
 and quick in its action. The bisulphide of calcium is pre- 
 pared either by passing a stream of sulphuretted hydrogen 
 gas into a thick milk of lime, until the latter is super- 
 saturated, or by taking equal parts of sulphur and quick- 
 lime, and after slaking the lime as usual, boiling these 
 substances together in water. The paste thus obtained is 
 brushed or painted carefully over the hair side of the hide 
 while spread upon the floor. After the hides have been 
 well soaked, a light coating of the paste is given, but suffi- 
 cient to reach the surface of the skin. Since the sulphide 
 would readily destroy ordinary brushes or swabs, we should 
 think that brushes might be made with asbestos — a material 
 which would not be so readily, if at all, acted upon by the 
 caustic sulphide. As the skins are brushed over with the 
 sulphide they are laid one above another, hair to hair, 
 about twenty in a pile. After about two hours the position 
 of the skins is reversed by lifting the uppermost pair and 
 laying them by the side of the pack, and upon these the 
 other pairs are placed in succession, when the bottom pair 
 of the first pack becomes the top pair of the second heap, 
 by which a more uniform action of the sulphide is ensured. 
 In about four or five hours from the commencement the 
 skins are in a condition for unhairing on the beam in the 
 ordinary way ; they must, however, be previously soaked 
 in cold or tepid water. 
 
 It is stated that although the sulphide is so powerful 
 in its action upon the cuticle and hair (which become 
 practically destroyed), no injurious effect is produced upon 
 the gelatine of the pelt. One serious objection to the 
 employment of sulphides in the above operation is the 
 highly offensive and injurious odour which these sub- 
 stances exhale, and which cannot be long endured by the 
 workmen with impunity ; indeed, most disastrous effects 
 are known to have resulted from their employment. 
 
 The waste lime from the alkali works, which is bi- 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 133 
 
 sulpiride of calcium in a concentrated form, and also the 
 waste lime from the gasworks, which is of the same com- 
 position in a less active state, have each been the subject 
 of a patent, the latter being stated to unhair the skins in 
 from four to eight days. If it be a fact, as stated, that 
 the bisulphide of calcium has no effect upon the gelatine 
 of which the true skin, or pelt, is chiefly composed, this 
 substance should prove more economical than the ordinary 
 process of liming, by which a considerable loss of gelatine 
 is said to be sustained, although this is disproved by Dr. 
 Davy, as we have shown. Since the bisulphide of calcium 
 does not raise the pelt, this must be effected by after 
 treatment in the dilute acid bath before the hides are sub- 
 jected to the tanning operation. 
 
 Depilation by Charcoal. — This process was patented by 
 Anderson in 1871. Wood charcoal was applied as a 
 substitute for lime, and in much the same way. The hair 
 was effectually loosened, but the process was simply one 
 of putrefaction, as in the ordinary " sweating " processes, 
 while the charcoal acted as a deodorising agent. 
 
 Depilation by Sulphide of Sodium. — For sole leather 
 Eitner recommends the following method of applying this 
 powerful depilatory : — Dissolve 4 or 5 lbs. of the sulphide 
 in each gallon of water. Form this into a thin paste with 
 lime or pipeclay. The paste is to be spread evenly over the 
 hair side of the hide, which is effected by one workman 
 pouring it from a pail down the middle of the hide, while 
 another, with a mop or cane broom, rubs it into every part. 
 The hide is then folded into a cushion and set aside. In 
 from fifteen to twenty hours it will be ready for unhairing, 
 when it will be found that the hair is reduced to a pulp, 
 and therefore totally destroyed. In the above concen- 
 trated condition the hair would, doubtless be destroyed in less 
 than an hour. The hides are now thrown into cold water, 
 to wash away the sulphide and to enable them to plump. 
 The sulphide being highly caustic, it will, if not removed 
 by washing, attack the nails and skin of the workmen, 
 who should be thoroughly cautioned as to its use, other- 
 wise they will soon suffer from " alkaline sores " of a most 
 
134 LEATHER MANUFACTURE. 
 
 painful character. This method of unhairing gives good 
 weight, as also tough and solid leather, but it requires to 
 be used with very great care. If not spread evenly upon 
 the hide, patches of hair may remain upon the pelt, which 
 will be troublesome to remove afterwards. Against the 
 advantages derived from the quickness of this process 
 must be placed the cost of the material and the loss of 
 the hair. Moreover, unless the hides, after being treated 
 by the sulphide, are plumped by steeping in weak lime, 
 the fleshy matters will be difficult to remove on the beam. 
 Raising by acid is also considered necessary, since the 
 sulphide itself has but little plumping effect. 
 
 In applying this process to dressing hides, the sulphide 
 is used in a more diluted condition, the hides being sus- 
 pended in a solution of the sulphide, three-quarters of a 
 pound being used per hide. After suspension in this 
 solution for about twenty-four hours, the hides are in the 
 condition for unhairing, after which they are limed as 
 before, to plump or swell them. 
 
 Palmer's Process. — This process consists essentially 
 in subjecting hides or skins alternately to the action of 
 water and to that of the atmosphere. After the hides are 
 cleansed as usual, they may be subjected to this process 
 by placing them in an open wheel or cage, which is 
 caused to revolve, with its lower portion immersed in 
 a tank containing water, whereby the hides are alter- 
 nately plunged in that liquid, and as they are raised 
 out of the water by the revolution of the wheel, the air has 
 free action upon them. This action is kept up until the 
 hair or wool is ready to remove. After unhairing, the 
 hides or skins are again placed in the revolving wheel or 
 cage, and the operation continued until a " dark colouring 
 matter can be made to exude from them by ' scudding,' 
 when they will be found thoroughly cleansed, softened, 
 swelled, and prepared for the subsequent tanning or taw- 
 ing by any suitable process." The process is further 
 described as follows : " The hides or skins being well 
 soaked, are then submitted to the action of the open air 
 for about three days, according to the temperature of the 
 
DEPILATION, OR UNH AIRING SKINS AND HIDES. 135 
 
 atmosphere ; but in no case must it be long enough to 
 generate ammonia, as that would indicate incipient decom- 
 position, and therefore destruction of gelatine. The hides 
 are then returned to the water for about three days, after 
 which they are again exposed to the air, and so on, alternat- 
 ing the immersion and exposure for about a fortnight from 
 the commencement in the case of wet salted hides, when they 
 will be found to unhair or unwool readily ; but in the case 
 of the harder and drier descriptions of hides the process 
 will require to be continued, say, from a week to ten days 
 longer. After the hides are unhaired the alternate soak- 
 ing and exposure to the air is again repeated, once or 
 twice, until, on ' scudding/ the hides are found to dis- 
 charge a dark fluid, which I term ' suppressed perspira- 
 tion.' As an indication of the time when the hides have 
 arrived at the stage when this fluid can be removed, it will 
 be found that they give off a very disagreeable effluvium 
 (like that which arises from an over-driven beast), and 
 different from the ammoniacal smell usually given off by 
 hides under treatment. After the complete removal of 
 the said dark fluid, the hides will be found to be fresh, 
 pure, soft, and sweet-smelling, and they will swell in the 
 water and in the subsequent liquors to a better and higher 
 degree than hides treated by the ordinary and more 
 expensive processes. Such swelling of the hides will also 
 indicate the perfect removal of the said dark fluid. The 
 atmospheric temperature which I find best suited for 
 carrying out my process is about 65° Fahr. If the tem- 
 perature be higher, less time will be required, and if lower, 
 more time. 
 
 " The hides prepared as above described can be tanned 
 in a considerably shorter time than when prepared by the 
 known processes, and they will be found to have gained 
 from 100 to 112 per cent, in weight, instead of only 
 from 65 to 70 per cent., as is the case under the ordinary 
 processes of preparing them for tanning. As a pre- 
 paratory treatment, the skins or hides may be placed in 
 an open drum or cage, which is caused to revolve slowl} r 
 with its lower portion immersed in a receptacle containing 
 
13 5 LEATHER MANUFACTURE. 
 
 water, so that the hides are alternately immersed in the 
 water and then subjected to the action of the air, but this 
 arrangement need not necessarily be employed, and where 
 it cannot be conveniently adopted the hides may be at 
 once steeped in tanks for a lengthened time and then 
 exposed to the air as described." 
 
 Beck's Process. — In carrying out this process the 
 inventor makes a " water stove " instead of a fermenting 
 stove, but with this difference, that instead of having a 
 hermetically closed chamber, he employs an open vessel, 
 as a pan or basin ; he arranges hooks exactly as in the 
 fermenting stove, and upon these the skins are suspended 
 by the feet, side by side, care being taken to keep them 
 perpendicular. The skins being hung up and descending 
 nearly to the bottom of the pan, the latter is filled up with 
 water until all the skins are submerged. Into this " water 
 stove " fresh or beaten skins may be placed. " The pro- 
 longed stay of the skins in the water naturally causes the 
 peeling, and when this peeling takes place the skin has 
 not suffered at all in the water ; on the contrary, it has 
 gained in value, and the wool is entirely preserved. 
 When the moment for peeling has arrived, it is only 
 necessary to empty the basin or pan ; the skins are drained 
 separately, and they can be peeled easily. By this water 
 system I am also enabled, while preserving the skin and 
 the wool, to accelerate more or less the operation of 
 peeling. It is preferable to let the skins follow their 
 natural course, and cold water may be used both in 
 winter and summer. It will be understood that the skins 
 take longer to peel in winter than in summer, but no 
 harm is occasioned by that. If, on the contrary, it is 
 desired to accelerate the operation of peeling, I use tepid 
 or hot water, and I add to the bath any material capable 
 of hastening this operation, such as soap, soda crystals, 
 strained bran, water, &c, provided always that the mate- 
 rials employed are not such as would injure either the 
 skin or the wool. 
 
 " I may observe that if care has been taken to put the 
 Bkins into the water stove perfectly scoured and washed 
 
DEPILATION, OR UNHAIRING SKINS AND HIDES. 137 
 
 (by means of what is known as the Puech process, for ex- 
 ample), wool can be obtained of a value hitherto unknown. 
 By my process of peeling the leather obtained is not only 
 worth more, but it can be manipulated immediately by 
 the tawer, or it may be salted, and more especially it may 
 be dried without losing any of its quality." 
 
 The Pullman-Payne Process.— In 1898 Messrs. Pull- 
 man and Mr. S. Payne, of Godaluiing, patented the 
 method of liming bearing their name, and which appears 
 to have been used with a certain amount of success. The 
 method depends upon the fact that if a hide which has 
 been treated with caustic soda be subsequently treated 
 with a solution of calcium chloride, a double decomposi- 
 tion takes place and lime is formed in the fibre of the 
 pelt, the sodium uniting with the chlorine to form 
 common salt. In practice it was found that better 
 results were obtained if the hides were first immersed in 
 a putrefying soak, this bearing out what was known in 
 liming practice that there was some joint action of 
 bacteria and the alkaline solution which loosened the 
 hair roots in the process. If sodium sulphide is added 
 to the caustic soda, the putrefactive soak is not necessary, 
 but the hair is likely to be damaged, so that the stale 
 preliminary soak is an advantage. The patentees recom- 
 mend treating the hides in pits, and according to Procter 
 the caustic soda should not exceed a strength of one 
 pound in ten gallons (1 per cent). The hides, or calf- 
 skins, remain in this for about forty-eight hours, during 
 which they are once drawn and returned, by which time, 
 if the putrid soaking has been properly done, the hair 
 should be fully loosened. The hides are then drained 
 for two hours and passed into another pit containing a 
 solution of calcium chloride, which should be slightly 
 stronger than the caustic soda, say of about one and a 
 half pounds per ten gallons. The goods remain in this 
 for about forty-eight hours, during which they are drawn 
 once, and are then well washed in soft water (free from 
 temporary hardness), in which they may be kept for some 
 time without injury. 
 
CHAPTER XL 
 BAISING OB SWELLING. 
 
 Raising. — Bating. — The Bate, or Grainer. — The Pure. — Scudding. — 
 Sulphuric Acid Bate. — Turnbull's Process. — Warrington's Process. — 
 Bating with Barley-meal. — Lactic Acid for Bating. — Formic Acid 
 for Bating. 
 
 When the hides have passed through all the foregoing 
 operations, the pelts are soaked for a few hours, sometimes 
 for many hours, in water, for the purpose of removing the 
 lime as far as possible. The more lengthened soaking, 
 however, would, we should think, be not only absolutely 
 unnecessary, but certainly injurious, inasmuch as the water 
 would undoubtedly dissolve a portion of the gelatine of the 
 hide, and thus reduce its weight. The next operation to 
 which the pelts are submitted is termed raising or swelling, 
 in the case of heavy hides, or bating, puring, or drenching, 
 as applied to kips and skins, by which the whole or a 
 greater portion of the lime is removed from the interior 
 of the skin,* the pores become dilated or expanded, and 
 the fibrous structure of the skin is thereby rendered more 
 susceptible of the action of the tan liquors. 
 
 Raising. — For this purpose Macbride, in the year 1774, 
 applied very dilute sulphuric acid (oil of vitriol). The 
 hides were immersed for about forty-eight hours in an 
 acid solution composed of sulphuric acid 1 part and water 
 1000 parts. Since this acid, however, forms an insoluble 
 salt of lime (sulphate of lime) when coming in contact 
 with the lime absorbed by the skin, its employment for 
 this purpose could not, from a chemical point of view, 
 commend itself, although it has been very extensively 
 
 * The presence of lime, even in small quantities, not only produces a 
 harsh leather, but it also prevents the free action of the tannin. 
 
RAISING OR SWELLING. *39 
 
 adopted. On the Continent hydrochloric acid has been 
 employed for this purpose, and also as a substitute for 
 hating, to which we shall have next to refer. A more 
 rational system than either of the above has been much 
 adopted in France, and has found favour in this country 
 with some tanners ; this consists in steeping the hides, in 
 the first stage, in spent tan liquors, in which gallic and 
 other vegetable acids have been developed during the 
 process of tanning. These acids, combining with the 
 lime, form soluble salts of the earthy matter, which readily 
 become removed from the skin by the spent liquor in 
 which they are immersed. In this way the lime is effec- 
 tively, if-slowly, got rid of, while the texture of the skin 
 suffers no injury. In France sulphuric acid is believed to 
 have an injurious effect upon the pelt. 
 
 Bating. — This remarkable and primitive process is 
 generally confined to the treatment of kip hides, calves' 
 and seal skins, by the light leather tanner, and to the 
 skins of goats and other small animals by the skinner. It 
 has for its object the removal of the lime, whereby the 
 skin acquires the peculiar suppleness and pliancy essential 
 to leather of delicate texture. 
 
 The Bate, or Grainer, is essentially a lixivium com- 
 posed of the dung of pigeons and fowls in water. In 
 this unsavoury mixture the unhaired and fleshed skins are 
 immersed for a period of ten or twelve days, or for a shorter 
 period in warm weather. By this process of bating, with 
 alternate scraping or working, as it is termed, the lime is 
 believed to be converted into a soluble compound, and thus 
 becomes separated from the tissue of the skin, the mechani- 
 cal treatment doubtless aiding the operation considerably. 
 Dussauce says : " Investigation has shown that the above 
 matters contain an ammoniacal chloride that parts with its 
 chlorine on coming in contact with the lime, and so gives 
 rise to a soluble combination of this base — chloride of 
 calcium — that may readily be abstracted by water. But if 
 this is the only result of the noxious process, dilute hydro- 
 chloric acid should answer the same purpose. That this 
 disgusting method should still continue to be extensively 
 
140 LEATHER MANUFACTURE. 
 
 practised is disgraceful to modern science. It is stated 
 that in London alone £5,000 used annually to be ex- 
 pended in collecting and purchasing the above materials 
 for the sole use of the tanners of the capital and its 
 suburbs. Although this method of bating hides is toler- 
 ably effective, j r et it is well known to be attended with 
 serious disadvantages, not the least of which is the putre- 
 faction of the bate that is going on during the steeping, 
 and which injures the hides by acting upon the tissue of 
 the skin, reducing its weight in the first instance, and in 
 the second rendering it incapable of yielding the quantity 
 of leather it should doubtless produce did the above 
 changes not occur. Taking the hint from the action of 
 the alkaline chloride in this case, some tanners have 
 attempted to prevent the putrefaction induced by the 
 bating with excrements by avoiding its use altogether, 
 using hydrochloric acid in a diluted state as a substitute. 
 The innovation has not yet become very general in 
 England, although many tanners, especially in Paris, 
 are reported to have practised it successfully, the object of 
 the expulsion of the lime being satisfactorily gained by it, 
 and in addition to this the swelling of the hides also." 
 
 The Pure, which is applied to the skins of the 
 lighter kinds of calf, goat, seal, sheep, &c, is prepared 
 from the excrement of dogs, but, unlike the bate or 
 grain er, which is prepared with cold water, the pure 
 employed by the light leather dressers is employed warm ; 
 indeed, as hot as the skin can bear without scalding, as it 
 is termed. But it is an ascertained fact that the skin of 
 the dead animal can bear no more heat than the hand of a 
 living human being, without suffering irreparable destruc- 
 tion. While immersed in the pure, the skins are re- 
 peatedly moved about, and the pureman has to exert the 
 utmost caution to prevent the decomposition which ensues 
 from injuring the skins. The action of the pure is not 
 only rapid but powerful, especially in summer weather. 
 
 Scudding. — The workman forcibly scrapes the skin on 
 the beam, which operation is called scudding, by which 
 he removes the decomposing agent and the salt of lime 
 
RAISING OR SWELLING. 141 
 
 (chloride of calcium) formed during the immersion in the 
 pure; and in order to prevent further decomposition, 
 the pelts are thrown into clean cold water. The 
 bating and puring operations — especially the latter — are 
 considered the most critical of all the operations of the 
 tanner or leather-dresser. The pure, being employed 
 warm, accomplishes in a few hours that which the bate 
 requires days to effect. The applications of the bate and 
 pure will be further considered when treating of light 
 leathers and skin-dressing. 
 
 Sulphuric Acid Bate. — Sulphuric acid has also been 
 suggested as a substitute for the bate, but while its action 
 is not so marked as when hydrochloric acid (muriatic 
 acid) is used, it must also be remembered, as we have 
 before observed, that sulphuric acid forms an insoluble 
 compound with the lime, which no scraping or tvorking 
 can entirely remove. This acid, however, in spite of this 
 well-known fact, is generally used for raising or swelling 
 heavy hides after liming, and before they are placed in 
 the handlers in weak solutions of tan. 
 
 Turnbull's Process. — Dr. Turnbull introduced the em- 
 ployment of saccharine liquids for the removal of the last 
 traces of lime from skins as a substitute for the bate. For 
 this purpose 4 or 5 pounds of coarse sugar or molasses, 
 dissolved in 60 or 70 gallons of water, formed the bate. 
 In this process the sugar forms a soluble saccharate of lime, 
 which subsequent soaking and rinsing removes. 
 
 Warrington's Process. — In 1841 Robert Warrington 
 patented a process in which carbonate of ammonia was 
 employed as a substitute for the ordinary bate for grain- 
 ing skins. The carbonate of ammonia, however, although 
 it converts the lime into a neutral compound, does not 
 eliminate the earthy matter from the hide or skin ; conse- 
 quently it fails to promote the necessary suppleness and 
 softness of the skin, which are the chief objects of the 
 bating process. 
 
 Bating with. Barley-meal. — As a substitute for the 
 excrement bate, barley-meal, made into a sour liquor, is 
 much used. For 100 lbs. of dry skins, 50 lbs. of coarsely- 
 
1 42 LEATHER MANUFACTURE. 
 
 ground barley-meal and 5 or 6 lbs. of soured dough are 
 taken and intimately mixed with, water. Acetic fermenta- 
 tion soon follows, and the acid generated forms a soluble 
 salt with the lime in the skins, which becomes removed 
 by subsequent washings. 
 
 Lactic Acid for Bating. — Of late years lactic acid has 
 come into favour with the more progressive tanners for 
 bating or drenching. Its use is more desirable when 
 fancy shades are required, as it is stated the skins come 
 out much cleaner and clearer than by the old methods. 
 This is of much importance, as only the clearest skins 
 can be coloured fancy shades, and the fancy shades bring 
 a much higher price than the black leather. The usual 
 process for chrome-tanned calf skins is to use about half 
 a gallon of 50 per cent, lactic acid to 100 gallons of 
 water, or if the skins are lightly limed a little less lactic 
 acid may be used. The skins are bated in a paddle, and 
 water of about 85°-90° Fahr. is used, that is, the water 
 is 85°-90° Fahr. after the skins are in. Before they are 
 put in, the water should be at least 10° warmer. 
 
 For sheep skins, a little less lactic acid is used than 
 for calf skins, and if plump leather is desired, the water 
 is somewhat cooler, about 70° Fahr. For goat skins, a 
 "pure" is first used, and then the skins are bated in a 
 solution of 1 gallon of lactic acid to 400 gallons of water, 
 and at nearly 100° Fahr. 
 
 Formic Acid for Bating. — Formic acid is now used 
 for de-liming, and also as a preserving agent for sheep 
 pelts. An American plan is, after unhairing, to wash in 
 a weak solution of acid, using two and a half pints of 
 40 per cent, acid to ten hides. After fleshing and wash- 
 ing, the pack of hides is then washed in a solution of 
 five pints of formic acid in 135 gallons of water, or five 
 pints to 1120 lbs. of pelt. The hides are washed until 
 de-limed, that is, when a cut section remains white when 
 touched with a drop of phenol-phtalein. If the section 
 shows a reddish reaction the bating must be continued. 
 Formic acid is also used as a plumping agent, and for 
 developing " acid " colours in leather dyeing. 
 
CHAPTER XII. 
 TANNING BUTTS FOR SOLE LEATHER. 
 
 Bark Tanning. — Old Methods of Tanning. — Modern System of Tanning. 
 — Preparation of the Ooze. The Leaches. — The Handlers. — The 
 Layers.— Mixed Tannages. — Tanning hy Suspension. — The Sus- 
 penders. — Scouring. — Drying the Tanned Butts. — Old American 
 Method. — The Drying Loft. — American Turret Drier. — Working of 
 the Turret Drier. — Influence of Light upon Leather. — Striking. — 
 Eolling the Leather. — To determine when Leather is Tanned 
 throughout. 
 
 Bark Tanning. — While being probably the oldest mate- 
 rial used for converting hides into leather, oak-bark 
 although hemmed in by a host of competitors, still retains 
 its reputation as the best known source of tannin for the 
 preparation of sole leather. It is not on account of its 
 richness in tannic acid, for there are many vegetable sub- 
 stances which yield a far greater percentage of tannin 
 than oak bark, but doubtless its great advantages — which 
 are most fully developed in the layers — depend upon 
 the way in which it is employed. When ground oak- 
 bark is stratified between layers of skin deprived of its 
 cuticle, hair, and flesh, the whole being saturated with an 
 infusion of the bark, not only is the tannin gradually pre- 
 sented to the surfaces of the skins, or pelts, and the 
 strength of the liquor maintained by the ground bark until 
 it is exhausted, but the feeding of the leather with vege- 
 table extractive — which is a slow and occult process — 
 takes place, whereby the leather is materially increased in 
 weight and solidity. 
 
 After the hides have been subjected to all the prelimi- 
 nary operations of soaking, liming, unhairing and fleshing, 
 rounding and raising, the butts are ready for the tanning 
 
144 LEATHER MANUFACTURE. 
 
 process; and since this is conducted upon various sys- 
 tems, it will be necessary to treat of them separately, 
 commencing with the older methods, which, so far as 
 regards the excellence of the results obtained, have not 
 been surpassed, even though a host of gifted observers 
 have endeavoured to hasten the process without injury 
 to the quality of the product. It must be understood 
 that by the process of raising, the pores of the skin 
 become distended or swollen, by which it more readily 
 absorbs the tanning principle and its associate, vege- 
 table extractive. In this condition the butts are ready 
 for the suspenders or handlers, a series of pits in which 
 the pelts receive their first dose of tannin from weak infu- 
 sions of bark. 
 
 Old Methods of Tanning. — By one of the older methods 
 of tanning, the hides were limed in very weak lime 
 liquors, and the skins were brought to a condition for un- 
 hairing and fleshing in about three months. They were 
 then placed between layers of coarsely-ground oak-bark in 
 the pits, the layers of hide and bark being alternately 
 formed until the pits were full, when a final stratum of 
 bark was placed over the whole ; no water or other 
 liquor was allowed to enter the pits. After a few weeks 
 the hides were transferred to another pit with interposed 
 layers of fresh-ground bark, the top hide of the first pit 
 being placed at the bottom of the next pit (which was 
 previously strewn with ground bark) and so on until the 
 position of the whole pack was reversed. After about 
 three months the process was repeated, the spent bark 
 being substituted for fresh bark each time. These changes 
 were effected from time to time until the tanning was 
 completed, which generally occupied about eighteen 
 months, or even a still longer period. 
 
 An improvement in the above very slow method was 
 afterwards adopted with great success. This consisted in 
 filling the pits, after they had been filled up with alternate 
 layers of hide and ground bark, with soft water; and 
 when the tannin was found to be exhausted from the 
 liquor or ooze thus formed, the pits were emptied and 
 
TANNING BUTTS FOR SOLE LEATHER. 145 
 
 again filled with hides and fresh bark, and filled up with 
 water as before, these operations being repeated many- 
 times during a period of about fifteen months, at the end of 
 which time leather of most excellent quality was produced. 
 
 By another method, a layer of spent bark, about six 
 inches thick, was first spread over the bottom of the pit, 
 and over this about an inch layer of fresh finely-powdered 
 bark was placed, and upon this a hide was spread perfectly 
 flat ; another layer of fresh bark was spread over the hide, 
 then another hide laid above this, followed by another 
 layer of bark, and so on until the pit was full ; the whole 
 pile was j;hen covered with a six-inch layer of bark, termed 
 a hat. This being done, the whole was well trodden 
 down and sometimes stout planks or boards, heavily 
 weighted, were placed on the upper surface. The pit was 
 then filled up with a weak infusion of bark, or ooze, and 
 allowed to remain for two or three months, when the pit 
 was emptied and the hides were stretched and again 
 placed in the pit with alternate layers of fresh bark, and 
 the pic again tilled up with ooze as before. After three 
 or four months the process was repeated several times, and 
 at the last operation the pit was filled with strong ooze. 
 In about fifteen months the leather was perfect. 
 
 Sometimes it was the practice, under the older systems, 
 instead of filling the pits with water or ooze, to put a 
 little water into the bottom of the pit, the vapour from 
 which, rising upward, promoted the absorption of tannin 
 by the skins. 
 
 Modern System of Tanning. — The practice, under the 
 modern system of tanning, is to employ an infusion of 
 bark or other tanning material, instead of water, in all 
 stages of the process, and ooze of greater strength is used 
 than in the older methods, whereby considerable time is 
 saved in the conversion of skin into leather. The ooze is 
 employed at various degrees of strength, progressively, the 
 strongest ooze being reserved for the last operation. The 
 tanning strength of the ooze is determined by an instru- 
 ment called the barkometer, which is described in another 
 chapter. 
 
 L 
 
146 LEATHER MANUFACTURE. 
 
 In speaking of the modern system of tanning, as 
 distinguished from the older methods, we do not wish it 
 to be understood that an uniform system of tanning is 
 adopted by all manufacturers ; indeed this is so far from 
 being the case that it might be more correct to say that 
 each manufacturer adopts a method more or less modified 
 by his own experience and the discoveries and improve- 
 ments of inventors which have from time to time been 
 made known to him. And while some manufacturers, in 
 every practical art, are more desirous of seeking and 
 adopting useful improvements than others, it will 
 naturally follow that considerable progress may be made 
 in some establishments whilst others continue to work in 
 "the same old groove" until successful competition 
 renders a change inevitable. Again, the tanner's is a very 
 " close " trade, and is conducted with an amount of secrecy 
 that almost bars improvement, while it certainly checks 
 the progress of the art in this country. Jackson Schultz 
 says, with much truth, " When the English tanner shall 
 become as communicative as he is at present reticent, the 
 whole world will be enlightened as to the economy of 
 these agents, with those in use with tanners of the rest of 
 the world." This, however, we can scarcely expect while 
 our American competitors, in the language of Mr. Schultz, 
 " shoot at us from behind a hedge of more than 30 per 
 cent, import duty." 
 
 The process of tanning, as generally conducted at the 
 present day, we will now describe, but we recommend that 
 fair attention should be paid to some of the numerous 
 mechanical contrivances described in subsequent chapters 
 which have for their object the uniform diffusion of the 
 tannin throughout the whole of the pack or series of 
 hides in the earlier stages of the operation, as also those 
 mechanical devices which have been designed to economise 
 the labour of handling. 
 
 Preparation of the Ooze. The Leaches. — This is con- 
 ducted in vats or pits termed taps or leaches* These pits 
 
 * Also called letches or latches. 
 
TANNING BUTTS FOR SOLE LEATHER. 147 
 
 are usually about 9 feet square and 5 feet deep, each one 
 being capable of holding sufficient liquor for two handlers, 
 or pits in which the pelts are first treated with tan liquor. 
 The leaches are commonly fitted with a false bottom, so that 
 the liquor may be pumped or drawn off the spent bark as 
 required. The ooze is prepared by placing a quantity of 
 ground oak-bark in the pit, to which cold water is added, 
 and the liquor formed filters through the false bottom, 
 fresh water being introduced from time to time until the 
 bark is exhausted of its tannin. Some tanners prepare 
 their " liquors " or ooze with hot or lukewarm water, by 
 passing steam through a large iron pipe to the lower part 
 of a deep pit containing a mixture of the bark and water. 
 A little above the true bottom is a false bottom, through 
 which the liquor filters into the space below, and from 
 which it is withdrawn by suitable pumps. Steam pumps 
 are now generally employed for this purpose, as also for 
 transferring the liquors from one pit to another ; some of 
 these pumps are capable of distributing as much as 
 13,000 gallons of liquor per hour. By another system, 
 water is first applied to nearly exhausted bark, which 
 is allowed to remain at a moderate heat for . a consider- 
 able time, and the weak infusion thus obtained is pumped 
 into a pit containing bark somewhat less exhausted. 
 The liquor from this second pit is then transferred to 
 a third still richer in tannin, and so on through a series 
 of leaches until it reaches a leach or pit containing 
 freshly-ground bark, from which pit the liquor is with- 
 drawn for use. The liquors or oozes are termed re- 
 spectively handler liquor and layer liquor, the latter being 
 the stronger. 
 
 The Handlers. — When the butts have passed through 
 all the preliminary processes, they are transferred to the 
 handlers, a series of pits 7 feet by 5 feet, and 5 feet deep, 
 in which they are treated with weak infusions of bark, 
 commencing at about 15° to 20° by the barkometer, being 
 handled twice a day during the first two or three days, 
 either by turning them over in the liquor, or by taking 
 them out one by one and piling them in a heap, and 
 
148 LEATHER MANUFACTURE. 
 
 then replacing them fn reverse order in the pit. The 
 operation of handling is shown in Fig. 15. It is more 
 generally the practice, however, to work the handlers 
 in what is termed a round, which may consist of six 
 pits. In the first of the series the washed butts, as 
 they come from the beam-house, are placed ; or, when 
 susjjenders are employed (to which we shall presently 
 
 Fie. 15. 
 
 refer), those which have received a preliminary treatment 
 in these vats. The butts are placed in the first pit, one 
 by one, and are handled once or twice a day, by removing 
 them from and returning them to the same pit, after 
 which they are shifted to the next, and so on, through 
 the first four pits ; after which they are treated in the last 
 two pits of the series in this way : the butts are spread 
 out one by one in the next pit, each butt being sprinkled 
 over with a thin layer of finely-ground oak-bark, which 
 has the effect of keeping them from absolute contact, 
 
TANNING BUTTS FOR SOLS, LEATHER. 1 19 
 
 whereby the ooze more readily reaches all surfaces of 
 the butts, and at the same time augments the strength of 
 the liquor ; moreover, by this system the feeding of the 
 skin with tannin and extractive matter is greatly aug- 
 mented. After being thus treated, they are allowed to 
 remain for about two days, when they are removed, to allow 
 the introduction of fresh liquor and powdered oak-bark, 
 to which treatment they are subjected about three times 
 a week. The other packs follow in due succession, and 
 eventually the first becomes the most advanced, while the 
 last pack, fresh from the beam-house, becomes the first of 
 the next round, and so on. 
 
 When "all the pits have been worked in this way, the 
 last pit eventually contains merely the stale sour liquor 
 through which all the butts in the round have succes- 
 sively passed. This liquor is generally pumped into the 
 " suspenders," where such are employed, in which, any 
 tannin that may still be present becomes absorbed by 
 green or fresh butts, after which the liquor, being ex- 
 hausted of its tannin, is run oft' as waste. As each pit 
 becomes empty, it is cleaned out and recharged with fresh 
 clear liquor or ooze from the leaches, the strength of 
 which varies from 20° to 30°, according to the practice of 
 the tanner. 
 
 The treatment of butts in the handlers generally occu- 
 pies about six or eight weeks, by which time the colouring 
 matter of the bark and the tannin should have struck, 
 as it is termed, through about one-third of the substance 
 of the pelt. By this time the butts of the oldest packs 
 will generally have become covered with a peculiar 
 bloom, as it is called, and which is ellagic acid, a substance 
 insoluble in water ; the substance of the pelt is also 
 materially increased in weight, and is more firm and 
 solid. In this condition the butts are next removed to 
 the layers, in which they receive the final treatment of 
 bark and ooze, in progressive stages, until the tanning is 
 complete. 
 
 The Layers. — In these pits, which are termed lay- 
 away s by the Americans, the butts are stratified with 
 
ISO LEATHER MANUFACTURE. 
 
 ground oak-bark, which is carefully spread between each 
 butt to the depth of about one inch. A layer of bark is 
 first spread over the bottom of the pit, and a butt is then 
 laid over this, followed by another layer of bark, then a 
 butt, and so on until the pit is full, a layer of ground bark, 
 called a hat, being placed on the top. The pit is then 
 filled up with ooze at about 80° to 35°, more or less, ac- 
 cording to the practice of the tanner. The layer is then 
 allowed to rest undisturbed for five or six weeks, by 
 which time the tannin, with extractive matter, wall have 
 combined with the animal fibre. The butts are then taken 
 out, and the spent bark and ooze removed, after which 
 they are stratified with bark as before, and the pit then 
 filled, being in this second layer treated with ooze at about 
 40°. At the end of about three months, the butts are 
 again shifted, stratified with fresh bark, and treated with 
 a still stronger ooze. About the end of six months from 
 the commencement, the thinner butts will have become 
 perfectly tanned, while the stouter butts will require to 
 be treated again with fresh bark as before, with ooze at 
 about 60°, or even higher, and in this layer they must 
 remain for about six w r eeks or two months. Mr. Schultz 
 strongly objects to the practice of working butts of irre- 
 gular thickness in the same pack, and indeed common 
 sense would support his view, since it is obvious that 
 while the stouter butts would be imperfectly tanned, some 
 of the thinner butts, being tanned, would probably suffer 
 from prolonged immersion in exhausted liquor. 
 
 In shifting the butts from one pit to another, the top 
 butt of one pack becomes the bottom butt of the next, by 
 which change of position the action of the tannin and 
 the effects of pressure become to some extent equalised 
 throughout the entire pack. There appears to be no fixed 
 rule as to the strength of ooze, or the period of time 
 which should be allowed for tanning heavy butts, since 
 each tanner adopts a method of his own ; indeed, in this 
 as in every other branch of the art, there appears to be 
 considerable difference in practice — personal judgment 
 rather than fixed rule being the chief guide in most of the 
 
TANNING BUTTS FOR SOLE LEATHER. 151 
 
 operations of the tanner. A general view of the tan-pits 
 is given in the engraving Fig. 16. 
 
 Mixed Tannages. — As to the materials employed in 
 butt tanning, there is considerable difference in practice 
 at the various tanneries. While some tanners prepare their 
 liquors entirely from oak-bark, others use valonia for their 
 liquors, and employ ground bark only for sprinkling, or 
 " dusting " in the handlers ; other tanners employ two- 
 thirds valonia to one-third myrobalans in making their 
 liquors, or one-half valonia to one-fourth each mimosa and 
 myrobalans. Divi divi is not extensively used in butt 
 tanning owing to its liability to induce fermentation ; but 
 since it fs a cheap material and is reputed to give good 
 weight to the butt, there is a natural desire to employ it 
 as far as can be done with safety, with or without the use 
 of antiferments. In some tanneries, divi divi is used in 
 small proportions with each tap or leach, by placing it 
 beneath the other tanning materials, so as to keep it as 
 far as possible from the air. If, however, its suscepti- 
 bility to fermentation is due to mucilaginous or other vege- 
 table matter (which is most probable), its exclusion from 
 the air would not, we should think, be of much conse- 
 quence ; but its tendency to promote this decomposition 
 might be more readily checked by employing one or other 
 of the substances which have been found most effective 
 in arresting gallic fermentation. 
 
 Valonia is an important tanning material, but when used 
 alone it imparts an objectionable colour and harshness 
 to the leather; it is therefore most generally employed with 
 a moderate proportion of myrobalans. An excess of the 
 latter would be mischievous, since they are considered liable 
 to promote gallic fermentation. Mimosa is much used to 
 modify the colour of valonia, since it imparts an agreeable 
 pinkish tinge to the leather which is generally approved. 
 Being a powerfully astringent substance, while yielding a 
 strong colour, it can only be used in moderate proportions. 
 The tannin of this material requires to be extracted by 
 boiling water — steam heat being generally employed — 
 and the liquors are usually prepared in separate pits. 
 
TANNING BUTTS FOR SOLE LEATHER. 153 
 
 Mimosa liquors are not so susceptible of gallic fermenta- 
 tion as the tannins obtained from some other materials, as 
 divi-divi, for example. Grambier, or terra japonica, is fre- 
 quently added to the handler liquors in moderate propor- 
 tions, and is specially useful in keeping up the tanning 
 strength of the liquors. Of the many new tanning extracts 
 which are now largely imported into this country, oak- 
 wood, chestnut, hemlock, and mangrove are prominent, 
 and the two former have now firmly established them- 
 selves into favour ; but it will probably be a very long 
 time before any English tanner will use — from choice — 
 any tanning material but oak-bark for the preparation of 
 the best "quality of sole leather. Indeed, while the tan 
 colour of oak-bark remains the accepted colour of the best 
 English leather, it will be difficult to induce the trade to 
 recognise any leather, as of the best oak-bark tannage, 
 which presents a different tint to that to which they have 
 been so long accustomed. 
 
 Tanning by Suspension. — In some tanneries it is the 
 practice to suspend the hides in weak tanning infusions 
 before they are treated in the handlers. The object of 
 this system is to ensure the uniform absorption of tannin 
 by the pelts before subjecting them to the rough usage of 
 handling, which in the early stages of the process is liable 
 to cause injury to the delicate structure of the pelt. It 
 will be readily understood that after the pelt has become 
 partially tanned it is less susceptible of injury, and any 
 method, therefore, which will effect this object without 
 subjecting the delicate texture of the unhaired skin to 
 the chances of abrasion, or to the rough treatment of iron 
 hooks, must be advantageous. When the hides have become 
 partially tanned, the}^ are more capable of bearing without 
 injury the rougher treatment which handling, however 
 carefully conducted, necessarily involves. 
 
 The Suspenders. — There have been many ingenious 
 contrivances introduced for suspending hides in the tan 
 liquors, both in the earlier stages of the process and also 
 for the complete tanning of hides, the latter of which 
 will be described hereafter. In one form of suspender 
 
154 LEATHER MANUFACTURE. 
 
 a stout wooden shaft is placed across the pit lengthwise, 
 being partially immersed in the liquor ; to this shaft about 
 20 hides are attached, one above another. When the 
 shaft revolves, the first or upper hide becomes lowered 
 into the liquor, followed by the second and third, and so 
 on, the entire pile of hides becoming unfolded as it were, 
 and one by one lowered into the liquor ; as the shaft con- 
 tinues to revolve, the hides become alternately exposed to 
 the air and the tan liquor. Doubtless it would be an 
 improvement if the hides could be kept under the liquor 
 the whole time ; still the exposure to the air is only 
 momentary, and certainly much less than in the ordi- 
 nary system of handling. By this method the butts 
 would undoubtedly be constantly exposed to fresh sur- 
 faces of tan liquor — a most important point to be reached 
 in all processes of immersion in which chemical action 
 plays a part. 
 
 The American Rocker Handler, described in another 
 chapter, is much adopted in the United States, and is, we 
 believe, used to some extent in this country. But although 
 in the early stages of tanning, when the object is to im- 
 pregnate the skins throughout with a moderate amount of 
 tannin, the practice of keeping the hides in motion while 
 in the weak* liquors is doubtless advantageous, in the 
 latter stages the reverse treatment appears to be accepted 
 as that which is most favourable to the proper feeding of 
 the hide and the production of good leather. This fact 
 was established by the older tanners and recognised by 
 Sir Humphry Davy and all observers of eminence who 
 had studied the subject. In support of this, Jackson 
 Schultz says, " Leather tanned while at rest will have a 
 firmer texture than if motion is used to aid the tanning. 
 This would probably be the testimony of the butt tanners 
 of Great Britain, and there is much in our own experience 
 to confirm such a view of the case." Indeed, when we 
 reflect that not only tannin but vegetable extractive enters 
 
 * If the pelts were immersed in strong ooze at first, they would become 
 ease-hardened, as it is termed, in which, state they would offer great 
 resistance to the further absorption of tannin. 
 
TANNING BUTTS FOR SOLE LEATHER. 155 
 
 into the composition of sound leather, it will at once be 
 apparent that this substance — not having the same affinity 
 for gelatine as tannin — would necessarily require a con- 
 dition cf rest to enable it to combine, even in small 
 quantity, with materials which have so powerful an affinity 
 for each other. To feed the leather properly, therefore, 
 rest during a greater portion of the time required for 
 tanning is an absolute necessity in the preparation of 
 what is known as leather — that is, not merely a spongy 
 compound of tanno-gelatine plus colouring matter, which 
 frequently passes under that name, but leather properly 
 so-called. 
 
 After the butts are removed from the layers, it is some- 
 times the practice to throw them into pits containing weak 
 tan liquor, and then to take them out one by one, and 
 brush them all over to remove particles of spent tan which 
 may have adhered to them ; they are then laid across a 
 beam called the horse to drain. It is usual at this stage — 
 especially with butts of the best bark tannage — to strike 
 them with the pin (Fig. 18) while still moist, to remove 
 the bloom ; but sometimes this is effected by laying the 
 butt flat on the scouring- table and rubbing it with a 
 stone called the scouring -stone, a tool provided with 
 two sharp edges produced, by working on a grindstone. 
 With this tool the workman removes every trace of 
 bloom from the grain side of the leather. The grain 
 side is next rubbed over with a damp cloth, then with a 
 dry one, and afterwards linseed oil is rubbed over the 
 grain to prevent the too rapid drying of this surface of 
 the leather. 
 
 Scouring. — This is sometimes effected by scouring- 
 machines, one of which, the " Burdon " scourer, is shown 
 m Fig. 17. See also Fig. 66, p. 408. After scouring it 
 is sometimes the practice to strike the leather with the 
 pin. to lay the grain, and after this the grain side is 
 oiled, and the butts then sent to the loft, where they are 
 hung up and allowed to remain until partially dried ; they 
 are then taken down, the flesh and grain sides slightly 
 damped, and the butts are next piled in a heap to sam, or 
 
156 
 
 LEATHER MANUFACTURE. 
 
 samm, as it is termed, for several days, by which the 
 leather becomes tempered, or in an uniformly moist and 
 
 Fig. 17. 
 
 softened condition. In this state it is ready for the first 
 rolling operation, which will be described further on. 
 
 Drying the Tanned Butts. — Although apparently a 
 simple process in itself, much skill and judgment on the 
 part of the workman are required to dry recently tanned 
 skins properly. If the drying be too slow, especially in 
 damp weather, the leather is apt to mould, which is very 
 injurious to it ; if, on the other hand, the drying be too 
 quick, or the leather is exposed to the direct raj r s of the 
 sun, it is liable to become discoloured, hard, and brittle. 
 A well- ventilated loft, in which the skins may be exposed 
 to a gentle but continuous current of air, without being 
 subject to the direct solar rays, is considered most favour- 
 able for uniform and perfect drying. 
 
 Old American Method. — The skins, when sufficiently 
 tanned, are taken from the pits without being shaken or 
 
TANNING BUTTS FOR SOLE LEATHER. H57 
 
 beaten, and are stretched on pegs or hung up by their 
 heads from large nails, each one being kept expanded by 
 two or three sticks passed through from side to side, 
 so that all parts may be uniformly exposed to the air. 
 When they have begun to whiten, and have become 
 slightly stiff, but before they are perfectly dry, they are 
 stretched out upon a clean place and scoured with the 
 spent tan with which they are still covered. "When well 
 cleaned in this way, they are then to be trodden out and 
 beaten with the soles of the feet in every direction upon 
 both sides ; and after the inequalities and protuberances 
 of surface Lave been made to disappear by the flatten- 
 ing process, they are assorted in sizes and piled up in 
 heaps. While the skins are stretched in the drying- 
 room they should be beaten twice daily, morning and 
 evening, upon the flesh side with a round-faced wooden 
 mallet. If the skins should be dry, the operation may be 
 facilitated by moistening their surface with a wet brush. 
 This process imparts firmness, but the operations are now 
 almost entirely done by machinery. 
 
 The Drying Loft, or Shed, as it is sometimes called, 
 is a capacious wooden structure, one or more stories high, 
 according to the extent of the works. It is provided with 
 a series of openings all round the apartment, through 
 which the wind from any quarter can pass freely, and 
 thus traverse through the suspended hides. These openings 
 are protected by weather-boards, or trap doors, which can 
 be placed at such an angle that while the air maybe admitted 
 as required, the direct rays of the sun can be prevented from 
 reaching the leather. The circulation of air is further 
 aided by a portion of the flooring being composed of 
 narrow boards placed at a certain distance (about 2 inches) 
 apart from each other, whereby air is admitted from 
 below as well as at the sides and ends of the shed. To 
 facilitate the drying, especially in cold and damp weather, 
 a series of 4-inch flanged iron pipes, for steam or hot air, 
 are fixed above the floor, this range of piping extending 
 all round the interior of the shed. These pipes are fre- 
 quently heated by waste steam from the boiler. Although 
 
158 LEATHER MANUFACTURE. 
 
 this system of artificial drying is by some persons be- 
 lieved to be injurious to the leather, on the ground 
 that the heat dries the air, it must be borne in mind 
 that the moisture given off even from merely damp 
 hides would be amply sufficient to compensate for the 
 natural moisture expelled by the heat from the steam- 
 pipes. "When the drying of the hides is near completion, 
 however, greater caution would undoubtedly be neces- 
 sary in subjecting them to the continued action of hot-air 
 pipes. 
 
 The hygroscopic condition of the air — that is, the presence 
 or absence of moisture — may be determined by means of an 
 instrument called the hygrometer, of which there are several 
 different forms. " Mason's hygrometer shows the relative 
 dryness and moisture of the atmosphere by the degree of 
 cold produced by evaporation from a given surface. If 
 two delicate thermometers have their bulbs covered with a 
 thin piece of muslin, and if the one be dry and the other 
 moist, the depression of the latter will be directly as the 
 rapidity or amount of evaporation, and this again will 
 chiefly depend upon the state of the circumambient air as 
 to moisture ; if it be charged with vapour, no evapora- 
 tion from the wet bulb will ensue, and consequently the 
 mercury in that thermometer will remain stationary ; if, 
 on the contrary, the air be very dry, it will eagerly ab- 
 stract vapour from the humid surface, and a corresponding 
 degree of cold will be indicated by the depression of the 
 mercury in the humid thermometer as compared with the 
 standard or dry thermometer." — Brande. 
 
 To roughly determine whether the drying of the leather 
 is complete in an apartment heated by steam or hot-air 
 pipes, a small pocket looking-glass, previously kept in a 
 very cold situation, might be used. If the glass be held 
 about half an inch from, or nearly touching, the suspended 
 leather, if moisture be still given off from its surface this 
 will be at once condensed on the face of the glass, as if 
 it had been breathed upon ; if the reverse is the case 
 (provided that the glass be cold) it may be concluded that 
 the leather is perfectly dry. 
 
TANNING BUTTS FOR SOLE LEATHER. 159 
 
 In some tanneries the drying sheds have been heated 
 by hot-water apparatus in place of steam, and we believe 
 with success. 
 
 About 6 feet above the floor of the drying-loft a series 
 of rafters are fixed, and upon these are laid the wooden 
 poles, called "shed poles," from which the hides are 
 suspended. These poles are simply timber from which 
 the bark has been removed ; they average about 2|- inches 
 in thickness, and are from 6 to 8 feet in length. 
 
 American Turret Drier. — A brief description of the 
 American "turret drier" will prove interesting to those 
 who may \>e desirous of modifying their present method of 
 drying, or may require an extension of their present drying 
 arrangements. The following is abridged from Mr. Jackson 
 Schultz's admirable description of the turret drier : The 
 building may be any number of stories high, some being 
 three or four, while others are seven or eight. Mr. 
 Schultz, however, recommends but five stories, each about 
 7 feet clear between the beams, or high enough for a man 
 to pass with his hat on. Such a building need not be 
 made of very heavy timber, and therefore would be in- 
 expensive as compared with higher structures. The 
 building should be about two spans of timber — say 40 feet 
 — wide, with two rows of posts equidistant from the sides. 
 Longitudinally with these rows of posts should run a light 
 board partition, with intersections at every 10 feet, ex- 
 tending to the sides. This would cut the space up into 
 two rows of rooms about 10 by 12 feet each, with a centre 
 passage of about 13 feet. The roof is made of the usual 
 latticed lantern form from end to end. All the floors 
 above the ground-floor should be latticed, and the rooms 
 would of course be immediately above each other, so that 
 if the building were five stories high, there would be five 
 rooms, 10 by 12 each, standing one above another, and 
 there should be just as many of these rooms as would dry 
 the stock of the yard. The centre passage-ways should 
 be lighted by cross--sections leading to the windows, and 
 each room should contain one small window close to the 
 top to admit light only. There should be no openings 
 
160 LEATHER MANUFACTURE. 
 
 except at the base of the lower room, with the air leading 
 directly on the piping. 
 
 Each room will hold one pack of 100 or 120 hides, 
 depending upon the weight of leather, and will dry the 
 same in ten days. The rooms on the first floor should be 
 supplied with steam-pipes laid on the floor, or raised 
 only a few inches above it. The heating of the pipes 
 should be under separate control, so that any degree of 
 heat can be admitted, and the steam turned on or off at 
 pleasure. 
 
 Working of the Turret Drier. — All the packs taken 
 out in one day, or in two or more days in succession, 
 should go into one of these sections, so that the condition 
 of the leather may be as nearly uniform as possible in each 
 set of rooms. The leather is hung upon sticks, in double 
 rows, leaving a passage of nearly two feet between. No 
 steam should be allowed to enter the pipes or the section 
 during the first three or four days, neither should the 
 trap-doors, which lead outwardly, be opened but slightly 
 except in warm weather, or when the wind blows high ; 
 but in autumn, or during overcast weather, the lower 
 trap-doors may be safely left open. About the third or 
 fourth day a low degree of steam heat may be applied, 
 and gradually increased until the seventh to the tenth day, 
 by which time the leather should be fully dried. All the 
 hides in both tiers and in all the five rooms will have dried 
 in about the same time, and may be replaced by others. 
 Mr. Schultz says, " One of the best guides that I can give 
 for the capacity and practical working of these driers in 
 connection with a tannery is this : one of these sections 
 should be large enough to hold one-tenth of ten days' 
 work. I have known turrets so actively worked as to 
 turn out stock in seven days ; but I prefer ten, since it is 
 very important not to hurry the drying during the first 
 
 few days The turret drier is, beyond all question, 
 
 the most efficient and artistic method yet devised for 
 drying leather, and, in some of its modified forms, should 
 be adopted by all tanners. The difference in the tempera- 
 ture at the ground and at an altitude of 40 or 50 feet 
 
TANNING BUTTS FOR SOLE LEATHER. 161 
 
 would of itself create a draught, as is well illustrated by 
 the erection of stacks or chimneys for the passing off of 
 smoke or gas. But, if to this natural action of the differ- 
 ence of temperature we add a little steam heat, a steady 
 yet moderate circulation will be maintained from the 
 bottom toward the top or opening of this structure, carry- 
 ing upward and off the dampness from the leather, without 
 creating such violent currents of air as to stain and injure 
 the colour." 
 
 Mr. Schultz says that it is believed that the principle 
 of the above method of drying sole leather could be 
 applied with equal advantage to all other kinds of 
 leather ; and indeed, when we consider that the gentle 
 motion of the heated air — constantly ascending as it 
 does from the steam-pipes — must keep up a continued 
 circulation of the air within the drying-rooms, this 
 should be the most favourable condition under which even 
 the most delicate leathers could be dried, provided that 
 the temperature were kept as low as possible to effect the 
 object. 
 
 For the purpose of conveying the hides to and from the 
 drying-rooms, lifts or elevators are employed, which may 
 be of any approved construction ; but Mr. Schultz speaks 
 very highly of an endless chain elevator which he strongly 
 recommends to all tanners. This consists of an endless 
 chain, running from the extreme bottom to the top floor, 
 ending under the roof. The chain runs in a wooden box 
 enclosed on three sides. The open or outer side serves to 
 attach the hides by means of hooks fixed to the links of 
 the chain at a distance of about 4 feet. The distance 
 between the attaching hooks should be sufficient to enable 
 the workmen to attach below, and take off above, the sides. 
 By this simple method leather may be elevated with no 
 more actual expense than if dried on the ground-floor, and 
 l the hides, when once hung, remain until fully dried, thus 
 j saving all the expense of " shifting," &c. 
 
 Influence of Light upon Leather. — The influence of 
 light upon the colouring matter and juices of vegetable 
 substances is well known ; and while this is not so marked 
 
 M 
 
162 LEATHER MANUFACTURE. 
 
 when such matter is diffused through the cellular structure 
 of the plants — by which it is protected from the action of 
 light in some degree — if the vegetable substance be cut or 
 otherwise injured, a discoloration or darkening of the part 
 takes place rapidly afterwards. This is very noticeable 
 when we remove the epidermis or bark from a growing 
 plant ; the exposed surfaces soon assume a darkish colour, 
 which increases in depth by further exposure. Probably 
 absorption of oxygen may also influence the result. The 
 fact is specially recognisable in the case of the walnut, the 
 green covering of which is well known to impart a deep 
 brown stain to the fingers. The same may also be said of 
 young potatoes, in removing the skin from which the 
 domestic servant frequently finds the tips of her fingers 
 embellished by a brown stain. Now in the preparation of 
 oozes, or infusions of bark, the ground material, fresh 
 from the mill, is steeped in water — either warm or cold — 
 and while the tannin most readily enters into solution, 
 vegetable extractive and colouring matter also become dis- 
 solved in the menstruum. Now, what we wish to suggest 
 as the cause of the newly tanned leather becoming dark- 
 ened by exposure to air and strong light is this : that the 
 vegetable tissue in which the greatest amount of astrin- 
 gent property lies (the part which was nearest the wood) 
 also contains colourable matter which has not yet been 
 fully exposed to the action of strong light, and that an 
 infusion of this matter must, in the ordinary course of 
 things, become darkened by exposure to light. And further, 
 that when hides are steeped for a more or less lengthened 
 period in such infusion, the leather produced must be 
 acted upon and become discoloured, or darkened in colour, 
 by exposure to light, more especially while in a moist 
 condition. 
 
 Schultz says, " Leather dried in the open air will cer- 
 tainly dry dark, even if tanned with pure oak, and if 
 tanned with hemlock, or a mixed bark, will darken to a 
 damaging extent. If currents of air reach the leather 
 while in a wet state, a like result is produced, with the 
 addition of great harshness of grain. If a bright light, 
 
TANNING BUTTS FOR SOLE LEATHER. 163 
 
 particularly if the sun's rays reach the grain or flesh, the 
 acid of the leather turns brown, and is permanently dis- 
 coloured. The influence of the direct raj^s of the sun, or 
 even the strong light of the sun, on vegetation is a good 
 illustration of these influences on the colour of leather 
 containing vegetable acid in solution. The ordinary table 
 celery is covered with earth as fast as it grows to the 
 surface to keep the light from it, so that it may be white 
 and tender. Grass that grows under cover, excluded from 
 light, is white, not green. This law of light applies to 
 ail vegetation. Availing ourselves of this principle of 
 light, we say that leather that is intended to be fair should 
 be dried in the dark, and as free as possible from currents 
 of air." 
 
 Although, as we have said, we believe that light has 
 a powerful influence upon the vegetable matter absorbed 
 by the hide, we believe that the oxygen of the air also 
 plays an important part in this discoloration, or rather 
 coloration, since from the examples we have given, 
 light alone could scarcely have produced the effect. The 
 scratched rind of the green walnut produces an almost 
 instantaneous stain, which may be partially, if not 
 wholly, due to oxidation ; while the celery referred to 
 by Mr. Schultz would doubtless (if not protected by earth- 
 ing up) acquire its natural green colour by the action of 
 light only. 
 
 Striking. — When the hides are partially dried, as we 
 have before observed, they are submitted to the operation 
 
 Fig. 18. 
 
 known as striking, which is accomplished with the striking- 
 fin (Fig. 18) a two-handled tool of triangular form present- 
 
164 
 
 LEATHER MANUFACTURE. 
 
 ing three blunt edges. A section of the blade of the tool 
 is also shown. The butt is thrown across a horizontal convex 
 beam, called the horse, and the workman, taking the tool 
 by its handles, presses it firmly over the grain side of the 
 leather, until the entire surface has been gone over. 
 Fig. 19 represents a workman in the act of striking a butt. 
 To economise labour in this operation several forms of strik- 
 
 ing. 19. 
 
 ing-machines, worked by steam, have been introduced. 
 The accompanying drawing (Fig. 20) represents the 
 striking-machine of Messrs. Huxham and Browns, and 
 Fig. 66 that of Messrs. Wilson, the latter being generally 
 used in British yards for butts and bends. It is stated 
 that leather struck in these machines acquires a solidity 
 and firmness superior to that of hand work, while it also 
 enables the tanner to do with less rolling. The workman, 
 by a weighted adjustable foot lever, regulates the pressure 
 instantaneously, so that no part of the leather remains 
 untouched. Although hand striking is still much applied, 
 there can be little doubt that in this, as in many other 
 operations of the tanner, machinery, from the rapidity 
 
TANNING BUTTS FOR SOLE LEATHER. 
 
 i65 
 
 of its action, will eventually supersede hand labour to 
 a great extent. 
 
 Rolling the Leather. — When the butts are partially- 
 dried, they are submitted to the first operation of rolling. 
 For this purpose hand or steam rollers are used. The 
 hand machine consists of a brass cylinder or roller, sur- 
 mounted by a heavily weighted box-truck, and furnished 
 with a long handle. The butt is laid flat upon a solid and 
 level wooden bed coated with metal (zinc or brass being 
 generally used), and the workman passes the roller back- 
 wards and forwards until every part of the butt has been 
 repeatedly passed over. Fig. 21 shows the method of 
 using the hand roller. After the first rolling, the butt is 
 again hung up to become further dried, when the oiling 
 and rolling are repeated, and if necessary, the two surfaces 
 of the butt are moderately damped each time before 
 repeating the rolling. There are many ingenious and 
 effective machines for steam rolling, which, as will be 
 readily understood, effect a great saving in labour, besides 
 being more uniform in their action than could be expected 
 
1 66 
 
 LEATHER MANUFACTURE. 
 
 from the smaller or hand machine. In Fig. 22 is shown 
 a rolling-machine as supplied by Huxham and Browns. 
 
 mm 
 
 Fig. 21. 
 
 The roller is hung upon strong springs, which allows it 
 to adjust itself to inequalities in the thickness of the 
 
 Fig-. 22. 
 
 leather. "When in use, the leather is laid flat on an 
 ordinary zinc or brass bed, as in hand rolling, and the 
 
TANNING BUTTS FOR SOLE LEATHER. 
 
 167 
 
 roller passed oyer it, so as to avoid the stretching and 
 cockling of the leather which it is said some machines 
 are liable to cause. Fig. 23 represents the American 
 Pendulum Roller. It is said to be especially suitable for 
 leather requiring heavy rolling, such as buffalo, kip hides, 
 &c. Speaking of this machine, Schultz says that it is 
 claimed that if used at its full pressure the machine has a 
 sufficient power to actually cut the leather in half. It is, 
 
 Fie-. 23. 
 
 however, fitted with adjustable spring bearings, enabling 
 the roll to adjust itself to unequal thicknesses in the 
 leather, and the pressure may be regulated at will. 
 
 To determine when Leather is Tanned throughout. — 
 This is ascertained by making a clean cut with a sharp 
 knife in the stoutest part of a butt, when, if the tanning 
 is complete, the leather exhibits an uniform colour 
 throughout its entire substance ; if, on the contrary, a 
 light-coloured streak is visible in the interior, the process 
 is not complete, and the butts must be submitted to 
 further treatment in the layers until the proper point is 
 reached — a perfectly uniform colour throughout the entire 
 substance of the skin. Beyond this point, however, the 
 further steeping of the butts can do no good, and may 
 therefore possibly do mischief in proportion to the length 
 of what may be termed unnecessary time they may be 
 
1 68 LEATHER MANUFACTURE. 
 
 immersed in the tan liquor. The aim of many tanners 
 appears to be to ensure a good bloom upon their leather — 
 as a guarantee, we presume, that it has been bark-tanned 
 by a gradual and not by a quick process ; but when the 
 perfect and complete tanning is effected, protracted 
 immersion in the pits, merely to increase the deposit of 
 ellagic acid or bloom, to give an appearance to the 
 leather which cannot enhance its durability, would appear 
 a mistaken practice, and one which the American tanners 
 — who are making great progress in the art — seem to 
 ignore. 
 
CHAPTER XIII. 
 
 TANNING PROCESSES. 
 
 The first English. Patents for Tanning. — Newton's Tanning Process. — 
 Aldrich's Process. — Orgereau's Process. — Jennings's Process. — Bal- 
 latschano and Trent's Process. — Lomas's Process. — Michel, Kollen, 
 and Hertzog's Process. — Keasley's Process. 
 
 As in the case of every other art, innumerable patents 
 have been obtained, both at home and abroad, for improve- 
 ments in the processes of tanning, and for the machinery 
 and implements employed therein, besides many others 
 for inventions more or less connected with the manufac- 
 ture of leather. It is of the greatest importance to those 
 who pursue an art or manufacture that they be acquainted 
 with such modifications of the ordinary methods of work- 
 ing as may be likely to render their procedure more facile 
 or more economical, or otherwise tend to render their 
 manufacture more perfect in its results. With this view 
 we have selected from the lengthy roll of patented inven- 
 tions certain processes which we hope may prove in some 
 degree interesting and useful. While refraining from 
 making any comments upon the merits of any of these 
 processes, we may indulge a hope that from some of them 
 at least may be gleaned a fair amount of useful in- 
 formation. 
 
 The First English Patents for Tanning. — As speci- 
 mens of the orthography of the seventeenth century, the 
 following quaint titles of specifications may prove inte- 
 resting. The first patent for improvement in leather was 
 
170 LEATHER MANUFACTURE. 
 
 obtained by John Jasper Wolfen, and is dated December 
 8th, 1627. It runs as follows : — 
 
 " A newe invention for the making and pparing of 
 etaine stuffs and skynns to hould out wett and rayne." 
 
 In 1635 Christopher Hunt obtained a patent for a 
 " ISTewe invention by way of i ymbrodering or hufling of 
 guilded leather upon several grounds fitt for hangings or 
 other furniture for houses.' " 
 
 In 1660, Charles Howard patented "A newe way for 
 the tanning, tawing, dressing, and pparinge all sorts of 
 rawe hydes and skinnes into leather in lesse time and with 
 lesse charge then formerly hath bin vsed." 
 
 Newton's Tanning Process. — The object of this pro- 
 cess is to hasten the operation of tanning by employing 
 certain earthy or metallic salts in combination with vege- 
 table astringent matter, by the joint action of which it is 
 said the combination of the albuminous matter of the 
 skin with the bases is promoted. "When other matter 
 than catechu is used, the latter, of good quality and con- 
 taining 50 per cent, of tannin, is taken as a standard for 
 regulating the proportion of the former. The skins must 
 as usual be unhaired and free from lime. For treating 
 100 calf-skins the following formula is given : — 
 
 Alum 20 lbs. 
 
 Salt 10 „ 
 
 Catechu 100 „ 
 
 Sulphate of alumina 4 „ 
 
 The latter salt may be used either alone or mixed with 
 2 lbs. of common salt. The three mixtures are dissolved 
 in water in separate vessels, and kept apart. The following 
 directions are given for applying the various solutions: 
 put into a vat one-fifth of the first solution, one-tenth of 
 the second, and one-fourth of the third ; immerse the 
 skins in this liquor, handle and stir them repeatedly for 
 a short time, then take them out. Now refresh the vat 
 by the addition of one-fifth of the first solution, one- 
 tenth of the second, and one-fourth of the third. .Replace 
 the skins in this mixture ; treat as before, but for a longer 
 
TANNING PROCESSES. 171 
 
 time. Hemove the skins a second time, refresh the vat 
 with one-fifth of the first solution, one-tenth of the second, 
 replace the skins in the vat, and allow them to remain for 
 some time, handling occasionally as before ; remove them 
 again, and mix in the vat the residue of the first and 
 third solutions, and one-fifth of the second. Replace the 
 s'vins in the vat, and a few days after take them out and 
 add to the vat the remaining two-fifths of the second 
 mixture. Four or five weeks are sufficient to complete 
 the tanning. 
 
 The above process may be modified by laying the skins 
 in a vat and stratifying them with 3 lbs. of moistened tan. 
 Other skins can be thus tanned, but the proportions must 
 be varied, as shown below : — 
 
 For 100 goat skins, take — 
 
 Alum 10 to 12 lbs. 
 
 Catechu 50 to 60 „ 
 
 Salt 6 „ 
 
 For 100 cow hides, take — 
 
 Sulphate of alumina 40 to 50 lbs. 
 
 Salt 20 to 25 „ 
 
 Catechu 500 „ 
 
 For ox hides, per hide, take — 
 
 Sulphate of alumina 14 to 16 lbs. 
 
 Salt 8 „ 
 
 Catechu 60 to 70 „ 
 
 Aldrich's Process. — It is well known that when green 
 hides have become dry the surface of the flesh side becomes 
 hard or "flinty/' and this condition is a source of much 
 trouble to the tanner, and necessitates severe mechanical 
 treatment to render the hides sufficiently soft to undergo 
 the several processes which convert them into leather. 
 Upon this subject Dussauce makes the following observa- 
 tions : " As a green hide becomes dry, by evaporation of 
 its liquid, the flesh side absorbs oxygen from the atmo- 
 sphere, which, combining with the fresh fibro-gelatinous 
 surface, forms a hard flinty scale. To free the hide from 
 
172 LEATHER MANUFACTURE. 
 
 the scale, and facilitate its softening, tanners submit it to 
 hard beam breaking, or to the action of a hide-mill, both 
 of which have the detrimental effect, to some extent, of 
 disturbing the uniform relations of the interposed gelatine, 
 and loosening the small bundles of fibres composing the 
 structure of the hide, thereby weakening the hide in its 
 textile strength ; nor have any of the modern soaks proved 
 less detrimental, depending as they do upon a putrefactive 
 condition (sweating). The first effect of such soak is to 
 decompose the parts of the hides easiest effected, generally 
 the fibro- gelatinous structure immediately beneath the 
 scale ; hence the frequent water peltings and running of 
 hides in the soak, particularly in warm weather." 
 
 As a substitute for the ordinary mechanical treatment 
 and soakings, which are thus so clearly shown by Dussauce 
 to be mischievous to the structure of the hides, Mr. 
 Aldrich, of St. Louis, U.S.A., devised a chemical process 
 by which it is said the hides may be rendered as soft and 
 pliant as when first removed from the animal. 
 
 Aldrich's process for the treatment of dry flint hides is 
 thus given : — 
 
 The hides are first soaked in clear water until pliant ; 
 they are then placed in an acid bath composed as follows : — 
 
 Acetic acid . 1 part. 
 
 Water 16 parts. 
 
 In from 24 to 36 hours the above solution will dissolve the 
 scale, by combining with its oxygen, and swell the fibres of 
 the hides, when they are to be immersed in the following 
 bath : — 
 
 Carbonate of ammonia 1 part. 
 
 Water 70 parts. 
 
 This solution, having a strong affinity for the acid 
 absorbed by the hide from the first bath, saturates it in 
 from 48 to 72 hours, leaving the hide in a naturally pliant 
 and soft condition, and so perfectly transformed from a dry 
 to a green condition that no tanner can detect the slightest 
 difference between stock tanned from dry hides so prepared 
 
TANNING PROCESSES. 173 
 
 from tlie green hides. The first cost of the acid solution 
 is two cents per gallon, or twenty dollars for a large pool 
 full, after which it can be used continually, attended with 
 no expense except pumping up and passing it through 
 the apparatus to renew its strength after it has been used. 
 The second solution is prepared from all bate water, and 
 is attended with no expense but pumping. 
 
 The above process is said to obviate all danger of damage 
 from taint or running, for its action is so perfectly anti- 
 septic that hides so softened may be kept for weeks in 
 water before being placed in lime ; also by keeping fibrous 
 and flanky hides in the first bath double the ordinary time, 
 they will plump up and be materially improved, and all 
 without any breaking whatever. 
 
 Orgereau's Process. — The object of this process is to 
 shorten the time usually occupied by the tanning process, 
 and which is effected by a systematic arrangement of the 
 materials employed. The skins are submitted to the 
 usual operations of depilation and raising, and are then 
 placed, in alternate layers of tan and skin, in a vat with a 
 perforated false bottom. This vat being about three- 
 fourths full, is drenched with water for the first operation, 
 and with weak tan liquor for the succeeding operations. 
 The liquid slowly penetrates into the mass, and after 
 having moistened the contents of the vat, runs through 
 the false bottom into a reservoir, from which it is convej^ed 
 back to the surface of the materials. The inventor em- 
 ploys six vats, each containing 100 native or 120 imported 
 hides. The liquid passing into the reservoir is daily dis- 
 tributed over the surface of the materials in the vat by 
 means of a pump. This operation is continued for one 
 month, at the end of which time the vat is emptied and 
 the spent bark replaced by fresh bark, and the same pro- 
 cess of infiltration repeated. A third operation is neces- 
 sary to obtain a proper tanning. The entire process 
 occupies four months, and the leather produced is stated 
 to be equal in quality to that obtained by the old method ; 
 100 parts of dry Buenos Ay res hides yield, by the above 
 process, 150 parts of leather. It may be mentioned that 
 
174 LEATHER MANUFACTURE. 
 
 the inventor of the above process is an eminent Parisian 
 tanner. 
 
 Jennings's Process. — In applying this process to thick 
 ox hides, they are first unhaired in the usual manner, 
 either by steeping them in a lime bath, or by the more recent 
 process of sweating. If lime has been used, the hides are 
 steeped in dilute hydrochloric acid after they have been 
 dehaired, and then washed. This operation proves and 
 fits them for the succeeding operations. They are now- 
 piled in batches of a dozen hides each, with a hurdle or 
 wicker between each pair ; they are then alternately 
 lowered into tanks filled with the following solution : — 
 
 Tank No. 1 is charged with a strong solution of alum, 
 to which 10 per cent, each of sulphuric and hydrochloric 
 acids are added. 
 
 Tank No. 2 is charged with a concentrated solution of 
 soda ash, to which is added 5 per cent, of tungstate of 
 soda. The skins or hides are immersed six hours at a 
 time in these tanks, then withdrawn and drained, and 
 transferred alternately from the first to the second tank, 
 and vice versa, until the hide is sufficiently hardened. 
 The condition of the hide is known by cutting a small 
 piece off with a knife. At this stage they are immersed 
 for six hours in a strong solution of tungstate of soda 
 alone, then lifted, drained, and placed in a liquor of soap, 
 made by dissolving 20 lbs. of soap in every 10 gallons of 
 water, and the hides agitated in this until the strength 
 of the soap is exhausted by being absorbed by the 
 hide. They are now washed in soft water, and finally 
 steeped for twenty-four hours in a common liquor of oak- 
 bark, after which they are dried and finished in the usual 
 manner. 
 
 Ballatschano and Trent's Process. — This is one of 
 the numerous quick processes, and is thus briefly described : 
 In the treatment of horse hides, more especially, by this 
 process a considerable increase in substance is said to be 
 obtained. The hides are treated with the following tan- 
 ning compounds, either singly, or in a certain order, or 
 mixed together according to the kind of hide, its thick- 
 
TANNING PROCESSES. 175 
 
 ness, and the various purposes to which, it is to be applied. 
 The compounds employed are : 1. A solution of chromate 
 of alumina in pyroligneous acid (wood vinegar) in the 
 proportions of about 1000 parts of water to 20 or 30 parts 
 respectively of the chromate and acid. 2. A concentrated 
 solution of argol,* to which is added a small quantity of a 
 protoxide (such as nickel) in ammonia. The argol bath 
 is said to have the property of considerably increasing 
 the substance of the hides after treatment in the bath 
 of pyroligneous acid and chromate of alumina, if the 
 hides, after being removed from this bath and rinsed, are 
 treated, while still wet, with the solution for twenty-four 
 to forty -eight hours, or longer. The patentees state that 
 the hides treated with the argol bath " are rendered so 
 sensitive to vegetable tanning agents that a bath of 1 
 part tannin in 1000 parts of water and 20 parts of pyro- 
 ligneous acid will tan a hide in thirty days, whereas a 
 hide not treated with the argol bath will, with the excep- 
 tion of the brown colouring, show no trace of tanning 
 under the same treatment." Tanning with the above 
 ingredients may be effected in various ways. Thus, if 2 
 parts of solution No. 1 are mixed with 1 part of solution 
 No. 2, the tanning of thick ox and horse hides can 
 be completely effected in the mixture in from eighteen 
 to twenty-one days. When possible to maintain the 
 bath at a constant temperature of from 72° to 82° Fahr., 
 the tanning can be more quickly effected. The raw 
 hides to be tanned by this process are to be prepared in 
 the usual way. 
 
 According to the purpose to which the finished leather 
 is to be applied, different mixtures of both solutions, 1 
 and 2, are employed. For example : — a, 2 parts solution 
 No. 1 and 1 part solution No. 2 ; b, the hides are first 
 treated with solution No. 1, and then for any desired 
 length of time with solution No. 2 ; c, the hides are 
 merely treated with solution No. 1. A small quantity of 
 carbolic acid is recommended to be added to the baths. 
 The hides treated by the above process must afterwards 
 * Crude bitartrate of potash, as deposited by wine. 
 
176 LEATHER MANUFACTURE. 
 
 be carefully washed and then finished in the usual way. 
 Before tanning, the hides must be completely freed from 
 lime. 
 
 Lomas's Process. — This process consists in tanning 
 with valonia, American pearlash, and oak-bark. For 
 ordinary hides and skins four baths are used. The first 
 bath is composed of a solution of valonia marking about 
 1° on Twaddell's hydrometer, and about 4 lbs. of 
 American pearlash in 160 gallons of the solution. In this 
 bath the hides remain about three days. The second bath 
 is composed of valonia solution marking 3° Tw., and of 
 pearlash in the proportion of 5 lbs. to 150 gallons. The 
 hides remain in this bath four days. The third bath is 
 composed of valonia solution at 7° Tw., and pearlash in 
 the proportion of 5J lbs. to 150 gallons, in which the 
 hides are immersed for seven days. The fourth or final 
 bath is composed of solution at 2° Tw., and pearlash 2| 
 lbs. to 150 gallons. Between each hide or skin, as they 
 are placed in the bath, about 6 lbs. of oak-bark or valonia 
 are spread, and in this bath they remain fourteen days. 
 For very thick hides the first two baths are the same as 
 for ordinary hides ; they are afterwards placed in a bath 
 composed of valonia solution at 9° Tw., and 2 \ lbs. of 
 pearlash to 150 gallons of solution, in which they remain 
 nine days. They are afterwards placed in a final bath, 
 similar to that used for the other hides, for fourteen days. 
 Instead of valonia, oak-bark or other equivalent tanning 
 material may be used. The hides are handled in all but 
 the last bath. 
 
 Michel, Xollen, and Hertzog's Process. — The object 
 of this process is to ensure rapid tanning, by which calf 
 skins may be tanned in a few hours, and cow or ox hides 
 in about forty-eight, while at the same time the leather 
 produced possesses all the flexibility and firmness indis- 
 pensable to a perfect product. 
 
 To carry out the invention a set of apparatus is employed, 
 the essential objects of which are, first, to regulate at will 
 during the operation of tanning the temperature of the 
 liquors in the operating tank and in the receptacle con- 
 
TANNING PROCESSES. 177 
 
 taming the hides to be tanned ; second, to regulate the 
 density of the liquors in the said receptacle and also to 
 change their nature as required for consecutive processes 
 without interrupting the operation of the apparatus ; third, 
 the clarifying of the liquors used in former processes, in 
 order to enable them to serve for future purposes ; and it 
 is by the combination of these means that, according to the 
 present invention, rapid tanning may be effected. For 
 these purposes the skins or hides are introduced into a 
 drum revolving on horizontal trunnions, one of which is 
 hollow, to admit of the passage of a suction-pipe leading 
 from a pwmp, and a delivery-pipe leading from a raised 
 liquor tank, both of which pipes descend in the drum 
 within a partition thereof, so as to draw the liquor there- 
 from and discharge it into the same at or near its lowest 
 point. From the pump a delivery-pipe passes up into 
 the tank, so that by the pump the liquor can be with- 
 drawn from the drum while this continues to revolve, and 
 can be discharged into the tank, it being made to pass 
 through a refrigerating apparatus on its way, while from 
 the tank the same liquor may either be discharged back 
 into the drum, after having been raised to any desired 
 temperature by means of a worm heated by steam or hot 
 water, or the liquor may be passed from the tank through 
 the pipes into one or more niters in order to be clarified, 
 the discharged clarified liquor being collected in other 
 tanks, whence it can be drawn by the pump and discharged 
 into the first-named tank again. 
 
 By these means, it will be seen that while the skins or 
 hides are being continuously subjected to the action of the 
 rotating drum, the liquor may at the same time be continu- 
 ously made to circulate from the drum through the pump, 
 refrigerator, and main tank back to the drum, whereby a 
 constant definite temperature of the liquor may be main- 
 tained during the tanning operation, the action of the 
 refrigerator and of the heating-worm in the tank being 
 regulated to any required degree. Or during the operation 
 the liquor may be continuously, or periodically, clarified 
 by causing it to pass from the main tank to the filters 
 
 N 
 
178 LEATHER MANUFACTURE. 
 
 and thence back to the pump, as described. Or again, 
 where the hides have to be subjected consecutively to a 
 series of different operations, requiring different descrip- 
 tions of liquors, these may also be all effected in one 
 and the same drum by withdrawing the liquors there- 
 from by the pump at the end of each particular opera- 
 tion, and supplying the liquor required for the next 
 operation from other tanks, which also communicate with 
 the pump by pipes. The delivery-pipe of the pump also 
 has a branch provided with a stopcock leading to a dis- 
 charge drain, so that any particular liquor that has been 
 employed in the drum and that is of no further use, can 
 be withdrawn by the pump and discharged to waste, 
 instead of being conveyed, into the main tank again. 
 
 The apparatus is thus described : — " Fig. 24 is a longi- 
 tudinal section, partly in elevation, and Fig. 25 is a plan. 
 A is a wooden drum mounted to revolve on a horizontal 
 axis, having at each side trunnions that work in suitable 
 bearings. On the one trunnion is fixed a worm wheel, A 1 , 
 gearing with a worm driven by any suitable motor, causing 
 the drum a to revolve slowly — that is to say, to make from 
 ten to fifteen revolutions per minute, according to the 
 nature of the hides operated on. The other trunnion is 
 tubular, and through it pass freely two pipes, a and b, 
 which are supported by an external bracket. The one 
 pipe, a, bends downwards within the drum nearly to its 
 inner periphery. A partition, p, having perforations 
 through it, separates the body of the drum from the end 
 space which the pipes a and b enter. A manhole, d, 
 which can be tightly closed by a cover, serves to admit 
 into the drum the hides to be operated on and to remove 
 them. The drum has inwardly projecting ribs or studs, 
 a 2 , which assist in agitating the hides as the drum revolves. 
 b is a pump having its suction communicating with the 
 pipe, a, and its discharge communicating by a pipe, d, with 
 the top of a service tank, e. In the course of the pipe, d, 
 there is interposed a refrigerator, r, consisting of a sheaf 
 of tubes within a casing supplied with cold water or brine 
 that is cooled by a refrigerating apparatus, which is caused 
 
TANNING PROCESSES. 
 
 179 
 
 to circulate through it while the liquid conducted by the 
 pipe, d, flows through the tubes. 
 
 " The service tank, e, is placed at a high level on a 
 platform supported by columns, so that there is free 
 
 
 Kar. 24. 
 
 Fiar. 25. 
 
 space under it. The top of the tank has an opening, 
 in which is suspended a wicker basket, e 1 , which serves 
 to retain solid matters discharged along with the liquid 
 from the pipe d. At the bottom of the tank, e, is 
 placed a serpentine pipe, k, through which steam or hot 
 
180 LEATHER MANUFACTURE. 
 
 water can be passed when required to heat the contents of 
 the tank. From the bottom of the tank the pipe b, pro- 
 vided with a stopcock, leads to the interior of the drum a. 
 At the side of the tank is placed a thermometer, h, to 
 indicate the temperature of the liquid in the tank. 1 1 are 
 filters, having within them perforated removable trays 
 made of copper, on which are placed filtering materials, 
 such as small pebbles, o, or a mixture of charcoal and 
 Spanish white, p l , to purify and clarify liquid conducted 
 from the tank e to the filters j j, from which it is pumped 
 back by the pump b, communicating with the tanks by a 
 pipe, 11. Other tanks, k and l, are provided to contain a 
 reserve of liquid and to allow of subsidence, these reserve 
 tanks being connected by supply pipes with the service 
 tank e, and having branch pipes, r, connected to the suction- 
 pipe, n, of the pump b. The branch-pipes to and from the 
 several tanks are provided with suitable stopcocks, so that 
 they can be charged or emptied as required. 
 
 "Bymeans of the apparatus arranged as above described, 
 the drum A, while it revolves, can be charged to any desired 
 Bxtent with tanning liquid supplied by the pipe b from the 
 tank e, and whilst liquid is so supplied liquid can be with- 
 drawn by the pipe a and pump b from the lower part of the 
 drum, and returned to the tank e cooled, if necessary, on 
 its passage through the refrigerator f, or heated, if required, 
 by the serpentine k ; thus the same liquid can be continu- 
 ously circulated through the revolving drum with its tem- 
 perature and quantity varied as required. Moreover, by 
 causing the pump b to draw from one or other of the 
 reserve tanks j, k, or l, the strength and quality of the 
 liquid can be varied, while still its temperature can be 
 regulated as above described. It is by a suitable regulation 
 of the temperature, strength, and quality of the tanning 
 liquid that acts in the drum a on the skins or hides which 
 are kept in movement by its rotation, with suitable varia- 
 tions of these conditions at the successive stages of the 
 tanning process, that we are enabled to effect rapidly and 
 completely the conversion into leather of high quality. 
 In order that the nature of the operation may be better 
 
TANNING PROCESSES. 1S1 
 
 understood, we will, by way of example, describe its 
 application to the two ordinary processes, so as to guide 
 a practical tanner to its application in these and in other 
 cases. 
 
 "I. Tanning Process for Soft Leather. — For calf and 
 other soft skins the drum is charged with about 560 gallons 
 of tanning liquor of ordinary composition, the tanning 
 extracts which it contains being selected to suit the colour 
 to be given to the leather. The density of the liquor should 
 be from 30° to 35° of the tanning density gauge [barko- 
 meter], and its temperature 50° to 60° Fahrenheit. The 
 skins to be treated with this quantity of liquor may weigh 
 from 1,400 lbs. to 1,550 lbs., and these are introduced 
 into the drum in their soft, hairless condition, along with 
 soleine (essence of distilled turpentine), in the propor- 
 tion of about 3J pints of soleine to every 220 lbs. of 
 skins. The drum thus charged is caused to revolve at 
 a circumferential speed of from 400 feet to 410 feet per 
 minute. In consequence of the ' fermentation ' or action 
 resulting, the temperature rises to 65° or 70° Fahr., at 
 which it is maintained for four or five hours. It is then 
 allowed to rise gradually to about 85° during a period of 
 twelve to fourteen hours, at the end of which time the 
 tanning is complete. 
 
 " II. Tanning Process for Hard Leather. — The process is 
 similarly conducted, but extended over a longer period, 
 according to the thickness of the leather, and with liquor 
 strengthened by addition of about 5 lbs. of divi divi to 
 every 100 lbs. of hides treated, or equivalent addition of 
 other tanning material. For cow hide, for instance, the 
 duration should be about 48 hours, the final temperature 
 being allowed to rise to nearly 100° Fahr. At the end of 
 the tanning operation the drum is almost emptied of liquor, 
 and the hides are subjected for about fifteen or twenty 
 minutes to the beating action of the revolving drum, after 
 which fresh and very strong tanning liquor is gradually 
 introduced into the drum, which is then kept revolving 
 for about two hours. This has the effect of rendering the 
 leather firm. The hides when tanned, whether for hard 
 
1 82 LEATHER MANUFACTURE. 
 
 or soft leather, when removed from the drum are soaked 
 for several hours in a weak liquor at the temperature of 
 the atmosphere. The liquors discharged from the drum 
 are filtered and clarified, and restored to the required 
 strength for a succeeding operation." 
 
 Keasley's Process. — This consists in the construction 
 and employment of certain apparatus, whereby the opera- 
 tion of tanning hides may be more conveniently, advan- 
 tageously, and effectually carried on than upon the 
 ordinary jilan. It is well known to all tanners that the 
 quality and weight of leather is much improved and 
 increased by occasionally removing the hides or skins from 
 the liquor, and exposing them for a short time to the action 
 of the atmosphere. The ordinary plan of doing this is 
 by pulling the hides or skins one by one out of the pit 
 by manual labour, with the assistance of a hooked instru- 
 ment. This operation takes considerable time, and when 
 the hides are large is a very laborious occupation. 
 
 By this invention a machine or apparatus is employed 
 by which a much better result may be arrived at, and at 
 the same time the operation may be shortened, the labour 
 considerably diminished, and the weight of the leather 
 increased. The apparatus consists of a square, rectangular, 
 or other conveniently shaped frame, from which the hides 
 or skins are suspended vertically in any convenient 
 manner. The dimensions of the framing from which the 
 hides are suspended must of course correspond with the 
 size of the pit, so that the frame belonging to each pit, 
 and with it the hides, may be raised or lowered at the 
 discretion of the workmen. Each of these frames con- 
 taining the hides is distinct and separate, and may be 
 raised and lowered separately by manual labour, with the 
 assistance of a windlass if required; but it is found 
 advisable to connect two contiguous frames together, so 
 as to make them counterbalance each other, and thus 
 considerably diminish the labour of working them. A 
 variety of means may be devised for carrying this idea 
 into effect, but those shown in the accompanying draw- 
 ings will be found fully to answer the purpose. 
 
 
TANNING PROCESSES. 
 
 183 
 
 Fig. 26 represents a side elevation, and Fig. 27 an end 
 elevation of one plan, in which the frames a a a a, filled 
 
 Fiff. 26. 
 
 with hides or skins b b, are suspended from the extremi- 
 ties of a vibrating beam or lever c c, by means of chains 
 
184 
 
 LEATHER MANUFACTURE. 
 
 or cords d d. The tan-pits or vats e e are shown in 
 section in both these figures. The beam or lever c c is 
 
 mounted at / in bearings 
 firmly fixed in the framing, 
 g g, for that purpose, and is 
 worked up and down by 
 means of chains or cords, h h, 
 which pass round a windlass 
 or barrel * i, below, and are 
 fastened at either end to the 
 extremities of the vibrating 
 beam. On the axle of the 
 windlass is mounted a 
 toothed wheel j, seen by dots 
 in Fig. 28, and is driven by 
 a pinion k, which is fixed 
 on the shaft I, and is actu- 
 ated by applying power to 
 the shaft by means of a 
 winch or otherwise. It will 
 now be understood that as 
 the pinion Jc, toothed wheel/, 
 and barrel or windlass i i, 
 are made to revolve, that one 
 end of the beam or lever c c 
 will be raised and the oppo- 
 site end depressed by one of 
 the ropes passing over and 
 the other under the barrel, 
 and by this means one frame 
 of hides will be lifted out of 
 the tan liquor while the 
 hides on the opposite one 
 are totally immersed. This 
 operation may be reversed 
 by merely turning the winch 
 in the opposite direction. The ascent and descent of the 
 frames is assisted by the forked guides m m (see Fig. 27), 
 which work against the vertical guide-rods n n. At 
 
TANNING PROCESSES. 
 
 185 
 
 night or at other times when it is necessary that the 
 hides on both frames should be immersed, this object 
 is easily effected by unhooking from the suspending 
 chains d d, by means of the hook r, the frame that is 
 already immersed, and then allowing the other frame to 
 
 1=^^ 
 
 Fiar. 28. 
 
 descend into the liquor, which it will easily do by its own 
 weight. When one of the frames is raised, it is kept 
 elevated by merely placing a leathern or wooden block 
 between the teeth of the toothed wheel j and pinion k, 
 and thereby preventing them from revolving. This stop 
 
1 86 
 
 LEATHER MANUFACTURE. 
 
 fully answers the purpose, and is found more convenient 
 than a pawl and ratchet-wheel. 
 
 Fig. 28 represents a side elevation of another plan of 
 carrying out the counterbalance principle. In this plan 
 
 Fi<?. 29. 
 
 the vibrating beam c c is suppressed, and the suspending 
 chains d d, and the working chains h h, are united together, 
 and form the chains o o, which pass over pulleys p p at the 
 outer extremities of the standards g g, and down between 
 
TANNING PROCESSES. 187 
 
 the two other pulleys q q, and wind the barrel or wind- 
 lass i i, as in the former instance. If, however, it is 
 thought more desirable, the pulleys p p and q q may be 
 attached to a beam, or the ceiling above, instead of to the 
 standards g g. The barrel i is furnished with a toothed 
 wheel j, and is driven by a pinion Jc, precisely in the 
 manner already explained in reference to Figs. 27 and 28. 
 
 In Fig. 29 is shown a means of raising the frames con- 
 taining the hides one at a time. In this case the pulleys 
 are fastened as before mentioned to a beam above, the 
 windlass or barrel being placed below. 
 
 Fig. §0 represents another plan of raising the frames. 
 In this instance several frames, with the hides or skins 
 suspended vertically, may be raised at one time, but not 
 upon the counterbalance principle. The frames with the 
 hides are raised by means of a rope s sss, which passes 
 over pulleys tttt, affixed to a strong beam u u u above. 
 One end of the rope s s is firmly fixed to the beam, as seen 
 in the drawing, and the other end is passed over the pulleys 
 1 1, and round a windlass at the other extremity of the 
 beam. The suspension cords of the frames are furnished 
 with a pulley v v, constructed in such a manner that it may 
 with facility be hooked on to, or detached from, the rope 
 ss, according to whether it be required to raise the frames 
 containing the skins out of the tan liquor or to allow them 
 to remain immersed. It will be found most convenient to 
 raise only one-half the number of frames at one time, 
 leaving the remainder in the tan liquor. In order to do 
 this the rope s s is brought down to every other frame, 
 and the pulleys v v hooked on to the rope ; then by turning 
 the windlass and causing the rope s s to become coiled 
 thereon, the frames, with the hides suspended therefrom, 
 will be raised out of the pits, the other frames which are 
 not attached to the ropes remaining immersed. "When 
 the first lot of skins have been exposed for a sufficient 
 length of time to the atmosphere, the frames are lowered 
 into the liquor again, where they are allowed to remain 
 by unhooking the pulleys v v, which connect them to the 
 rope s s, and those which were before immersed are 
 
LEATHER MANUFACTURE. 
 
 N/1 
 
 now to be raised by booking 
 them in their turn by means 
 of their pulleys v v on to the 
 rope s s. If thought desir- 
 able the counterbalance prin- 
 ciple may be applied to this 
 arrangement of raising and 
 lowering the frames by 
 merely enrplojang an addi- 
 tional rope, s s, passed over 
 pulleys, exactly similar to 
 the one shown in the draw- 
 ing. One end of this rope 
 also would be firmly attached 
 to the end of the beam u u, 
 and the opposite end to the 
 windlass or barrel ; or in- 
 stead of two ropes, one only 
 may be employed by having 
 it of sufficient length to 
 pass from the end of the 
 beam over the pulleys, round 
 the windlass, back again over 
 similar pulleys to the end of 
 the beam, so as to present a 
 double rope, to one part of 
 which the three frames 1, 3, 
 5, would be suspended, 
 while the other frames, 2, 
 4, 6, would be suspended 
 from the other rope. Now, 
 if a double rope, s, is em- 
 ployed there will be no ne- 
 cessity to detach the frames 
 from the ropes ; the pulleys 
 v v are merely made to run 
 freely on the ropes, and are 
 not required to be construc- 
 ted so as to hook on as before 
 
TANNING PROCESSES. 189 
 
 mentioned. It will now be understood that if the counter- 
 balance principle is carried out in this manner, one set of 
 frames will be elevated while the others are immersed, and 
 
 the action of 1 lowering one set will raise the other ; that is, 
 when the windlass is unwinding the rope to lower one set, 
 it is at the same time winding up the other rope, and 
 thereby raising those frames connected with it. 
 
X 9Q LEATHER MANUFACTURE. 
 
 Fig. 31 represents another plan of raising the frames. 
 In this plan a travelling windlass is used, which may be 
 made to travel along a railway or floor constructed on the 
 top of the beam above the frames. When it is required 
 to raise a frame with its skins or hides, the windlass is 
 moved along the railway or floor to immediately above 
 the frame ; then a rope with a hook at the end is let down 
 to the frame, which is then attached thereto. The frame 
 is then raised up by means of the windlass until the skins 
 are drawn out of the liquid and are completely exposed to 
 the atmosphere ; the frame is then suspended from a hook, 
 firmly fastened to the beam, where it remains until the 
 manufacturer thinks it advisable to immerse the hides or 
 skins. Again having raised one frame up and suspended it 
 from the hook, the attendant releases the rope belonging to 
 the windlass, and proceeds along the floor or railway with 
 the windlass to another frame, which he raises and sus- 
 pends from its hook in the same wa) r . When it is required 
 to lower the frames and their hides into the liquor, this 
 must be done by means of the windlass in exactly the 
 same manner. 
 
CHAPTER XIY. 
 
 TANNING PR CESSES. — Continued. 
 
 Page's Process. — Casimir Bez and Sons' Process. — Snyder's Process. — 
 De Bock's Process. — Funcke's Process. — Hamer's Process. — Cox's 
 Process. — Nossiter's Process. — Desmond's Process. — Burbidge's 
 Process. — Kleman's Process. 
 
 Page's Process. — 'By this process the hides and skins 
 are limed in weak and strong solutions, unhaired 
 "drenched" in hen manure or other suitable bate, and 
 immersed and handled in colouring liquors made from 
 equal parts of any suitable bark and sweet fern, cutch 
 and sweet fern, or gambier and sweet fern. A mixture is 
 then prepared with the following ingredients : 40 parts 
 of common salt, chloride of potassium, or ammonium, 40 
 parts of alum, and 13 parts of saltpetre. These ingredients 
 are thoroughly mixed and dissolved in four vats half filled 
 with water. The vats measure 6 feet by 4, and are num- 
 bered 1, 2, 3, and 4. One-third more of the mixture is put 
 in 3 and 4 than in 1 and 2 vats. After a " salt solution " 
 has been thus prepared, a " tin solution " is prepared as 
 follows : — To 2 gallons of the stronger salt solution are 
 added 2 quarts of oil of vitriol, 2 gallons of muriate of 
 tin of 140° to 150° Twaddell, 28 gallons of muriatic acid 
 of 20° to 30° Baume, and 2 gallons of nitric acid of 36° 
 to 40° B. The hides are tanned by being immersed in 
 the four vats successively, 1 pint of the tin solution being 
 first added to the solutions in vats 3 and 4, and 1 pint 
 added to each of these solutions whenever a fresh lot of 
 hides are put in. The colouring liquor first described 
 may, if desired, be made without sweet fern, or ex- 
 
192 LEATHER MANUFACTURE. 
 
 clusively from sweet fern. The tanning is said to occupy 
 a very short time, and the leather produced is stated to 
 be " exceedingly tough and close in fibre." 
 
 Casimir Bez and Sons' Process.* — This invention re- 
 lates to the tanning of hides by aid of a continuous flow 
 or current of tan liquor. The method is as follows : the 
 raw hides are suspended vertically on poles arranged 
 horizontally, and resting across the tan-vats or pits, 
 which are on a gentle incline to encourage the flow of 
 the liquid, and this latter is made and contained in vats 
 at a lower level than the tan-pits. The tanning sub- 
 stances are deposited on a grating above the bottom of 
 the pit in which the liquor is made, so that this pit has a 
 double bottom ; in the lowest portion is a suction and 
 force-pump for raising the tanning liquor (made in this 
 pit by admitting water above the tanning materials) to a 
 reservoir above this pit, and a little above the tanning 
 pits, which are a succession of vats arranged in pairs. 
 This reservoir is provided with a grating near the top to 
 prevent the passage of solid matters held in suspension, 
 and being filled as described the liquid overflows through 
 an aperture at the top of the first pair of pits, and fills 
 the next pair ; passing through an aperture at the bottom 
 of the pits, it again fills the next pair, and passes through 
 an aperture at the top, and so on, passing through open- 
 ings alternately top and bottom, till it reaches the last 
 pit. In this latter a pipe enters, and by a gentle slope 
 leads the liquid back again to the vat or leach, in which 
 it is made to go through the same course again, so 
 establishing a constant flow of liquid of uniform strength, 
 the skins being arranged vertically in each tanning-pit 
 on the poles running longitudinally, so that the tanning 
 liquor thoroughly washes the skins on all sides in its 
 passage, and so impregnates them with the tannin. 
 The reservoir containing the prepared liquid is provided 
 with an internal agitator to prevent any deposit that 
 might arise from being in a state of rest. When a 
 double set of tan-pits, and two pits for preparing the 
 liquors are employed, the same arrangement is adhered to, 
 
TANNING PROCESSES. x 93 
 
 and then a double-branched pipe leads the liquor from 
 each of the last rows of vats back to their respective 
 leaches. 
 
 The inventors observe : " Many systems and processes 
 for tanning have been employed for replacing pit-tanning 
 — which up to the present time has been the most success- 
 ful, both in an industrial and economical point of view. 
 For some years past it has been the custom to place hides 
 in the pits not only horizontally, alternated by vegetable 
 astringent matters, but also vertically, suspended across 
 poles, so that the skins hang in a tanning liquid ; but 
 this arrangement, whilst submitting all parts of the skin 
 to the immediate action of the tannin, has nevertheless 
 failed to produce the results expected. The inventors 
 attribute this to the decomposition of the tan liquor by 
 remaining stagnant, the essential parts of the liquor 
 precipitating, so that in a short time the skins are found 
 in a mere neutral mass. The inventors conceived the 
 idea of submitting the skins, whilst suspended in the pits, 
 in a position parallel to each other, to the action of a 
 tanning liquid which continually forms a double current 
 across the skins and passes naturally from one pit to 
 another, reaching the upper part of one to penetrate to 
 the bottom of the next pit, and so on in succession, so 
 that the constituents of this tanning liquid are constantly 
 agitated so as to form a homogeneous whole, diminishing 
 only in its action as it becomes more distant from its 
 source of production." 
 
 Description of Drawings. — Fig. 32 is a section following 
 the longitudinal axis of the pits as arranged, and as 
 embodying this invention. Fig. 33 is a plan of the same, 
 showing a twin or double arrangement. Fig. 34 is a detail 
 on a larger scale. " The tannic liquor is made in the pits 
 a a, at the head of the construction, and below the tanning- 
 pits, the reason of which will be hereafter explained. The 
 pits a a have double bottoms perforated with holes b, on 
 which the vegetable astringent substances are placed. The 
 water passing through these substances becomes impreg- 
 nated with the tannin and passes under the bottom b, having 
 
 o 
 
194 
 
 LEATHER MANUFACTURE. 
 
 acquired all the requisite qualities. A suction and force- 
 pump c, whose suction-tube c l , debouches between the 
 
 bottoms of the pits, transfers the tannic liquid to the lower 
 part of the juice or liquid-pit d, the top level of which 
 comes above a grating d 1 , intended to stop the solid 
 
TANNING PROCESSES. 
 
 195 
 
 Ffe. 34. 
 
 matters held in suspension in the liquid. This liquor 
 pit is furnished with an agitator gifted with two move- 
 ments, an up and down penetrating 
 motion and a simultaneous rotary 
 one. In this mariner the liquor, 
 which would become hard from rest, 
 is attacked not through the whole 
 mass, which would require consider- 
 able force, but progressively, as fast 
 as the agitator descends. Following 
 the line with the pit d, are a succes- 
 sion of pits more or less in number 
 and dimensions fff 1 , all alike, and two and two, all 
 having a fixed incline, to produce a natural flow of the 
 liquid at a gentle speed, regulated as experience may prove 
 requisite. 
 
 " The pits//have their sides pierced at the top with holes, 
 g, through which the liquid from the pit d reaches the first 
 pit, and the liquor from the pit f 1 enters the second, and 
 so on in succession till the last is reached. The pits f 1 , 
 whose sides are pierced below with holes h, consequently 
 receive the liquor of the pits / (which precedes them) at the 
 bottom, and the same pits/ receive it at the top, the result 
 being that the liquor from the reservoirs d, has a double 
 flow of transfer from pit to pit, and of ascent and descent, 
 in leaving the level of one to reach the bottom of the next 
 successively until the last is reached. In this a pipe h is 
 placed, reaching to the level of the liquid, and being gently 
 sloped, the weakened liquid is returned to its source, viz., 
 the pit a, and being renewed and strengthened, it is then 
 forced by the pump to form a continuous current. In the 
 pits// 1 // 1 , the skins to be tanned are suspended on wooden 
 poles m, resting across the partitions of the pit, all the 
 poles being arranged parallel with the direction of the flow 
 of the liquid. The skins consequently receive the action of 
 the tannic liquor all over them, which, however, becomes 
 weaker as the pits are further separated from the source of 
 origin of the liquor, which is then returned as described to 
 acquire renewed strength. As the strongest liquors are the 
 
196 LEATHER MANUFACTURE. 
 
 most dense, deposits are left at the bottoms of the pits, which 
 are occasioned by the liquid resting all night ; no ill effects, 
 however, result from this, the skins being hung in the pits 
 with the thickest parts downwards. Where double sets of 
 pits are used, the liquor is returned to the leach a by a 
 bifurcating pipe k." 
 
 After the skins have remained long enough they are 
 removed from the first pit and replaced by those from the 
 second, and then by the third, and so on till the last skins 
 are reached ; these are then put into the first pit, and fresh 
 skins placed where the last were removed from. By this 
 arrangement the skins throughout the pits that had received 
 the action of the tan liquor, from the top to the bottom, 
 now receive it from bottom to top. 
 
 Snyder's Process. — By this process the skins are sub- 
 jected to acupuncture after unhairing, and previous to 
 tanning. The skins or hides are punctured with small 
 holes partly through, or are perforated with holes en- 
 tirely through, either on the flesh or grain side, so as to 
 admit the tannin more freely and perfectly through the 
 skins. The best time for performing this operation is 
 when the hide or skin is in its most relaxed state. The 
 punctures may be made either with a hand instrument 
 with steel points, or by passing the hide under or over a 
 cylinder or flat surface covered with steel points inserted 
 at proper distances, varying from 100 to 300 to the 
 square inch. 
 
 De Bock's Process. — This process consists in immersing 
 the skins or hides, after they are unhaired, in a solution of 
 "mimosa catechu," subjecting them to handling, then 
 immersing them in dilute sulphuric acid, and finally in 
 water. In treating heavy skins, after having immersed 
 them in the solution of mimosa catechu and handled them, 
 they are taken out of the pit and drained ; a solution of alum 
 is added to the mimosa solution, as also a little vitriol, which 
 are well stirred in. The patentee states that in place of 
 alum a solution of sulphate of magnesia (Epsom salts) and 
 mimosa catechu may be employed, but that alum makes 
 the hides harder. 
 
TANNING PROCESSES. 197 
 
 Funcke's Process. — 1. The unhaired skins or tides are 
 passed through a solution of commercial soda, and then 
 hung up until nearly dry before subjecting them to the 
 tanning process. 2. The skins are immersed in a solution 
 of bark or other tanning material, to which is added a 
 dilute vegetable acid. By this solution the pores of the 
 skins are opened or extended while being exposed to the 
 action of the tannic acid. 3. The skins and hides are 
 again subjected to the action of a solution similar to 
 the above, with the addition of a stronger solution of 
 the vegetable acid, and its action is " softened " or molli- 
 fied by the addition of a solution of sugar. Finally, 
 while the skins or hides are subjected to the usual hand- 
 ling, they are treated with a solution of tannic acid until 
 the leather is finished ; but since the tanning liquor 
 used in this process is of such strength as to impart too 
 deep a colour for most purposes, the colour is reduced, 
 when requisite, by adding, in the last stage of the pro- 
 cess, sulphuric acid and salt to the tanning liquor in 
 which the skins are worked. The skins or hides are 
 partially dried after each operation before being submitted 
 to the next. 
 
 Hamer's Process. — The inventor says, " I suspend the 
 hides or skins within an air-tight vessel, so that the 
 tanning liquor therein may come in contact with every 
 part of each hide ; I exhaust the air from the tank, and 
 further keep the tanning liquor in motion during the 
 process, so as to prevent it separating, and so that it may 
 sweep off from the hides and skins the film of spent 
 liquor immediately it is formed. The apparatus I prefer 
 to employ is a rectangular wooden tank capable of being 
 closed air-tight with a lid ; within this tank is a frame 
 somewhat shorter than the tank, and capable of moving 
 to and fro endwise, this motion being given to it by a 
 rod which is attached to the frame. The rod passes out 
 through a stuffing-box in the end of the tank, and is there 
 connected with an eccentric, or other similar instrument. 
 The frame runs backwards and forwards in the tank on 
 suitable guide rails, and the hides or skins are hung on 
 
198 LEATHER MANUFACTURE. 
 
 laths at the other end of the frame, transversely, the length 
 of the tank. As the hides move to and fro, the tanning 
 liquor presses first on one side of them and then on the 
 other. The tank is connected with an air-pump, and is 
 exhausted during the process. Tanning liquor partially- 
 used may he passed from one tank to another, and air 
 may be forced into the tank which is being emptied, and 
 when the tank is emptied may be forced up to a pressure 
 of 5 or 6 lbs. to the square inch, so as to press out the 
 liquor remaining in the hides." 
 
 Cox's Process. — In this process a frame is used with 
 tranverse bars or cords, from which the hides to be tanned 
 are suspended. The bars can be moved to and fro, so that 
 the hides may be made to touch or not, as desired. The 
 frames can be lowered into or hoisted out of the pit by 
 any overhead traveller or other convenient mechanism. 
 Inclined partitions are applied to the pit, which are 
 preferred to consist of parallel fillets or bars, the edges of 
 which approach but do not touch each other. One of 
 these is at each end of the pit, but more may be used if 
 desired. When the hides are first lowered into the pit 
 they do not touch each other, so that the liquor may run 
 freely between them. After a time, half the bars are 
 moved towards one end of the pit and half towards the 
 other end, so that the hides rest on or against each 
 other and against the inclined partitions, so as to exclude 
 the passage of the liquor between them. The hides 
 are immersed in these two ways during the process of 
 tanning. 
 
 Nossiter's Process. — This invention has for its objects, 
 First, to employ frames or partitions to keep the hides 
 or skins separate in the pits, and not pressed on by the 
 hides and skins above. Second, pressing several hides 
 or skins piled together in a press, in order to remove 
 the spent liquor before again immersing them in fresh 
 liquor. 
 
 Description of the Drawings. — In tanning hides and 
 skins in pits, it is usual to pile them one on the other, so 
 that the lower ones are much pressed on, and the tanning 
 
TANNING PROCESSES. 
 
 m 
 
 liquor cannot pass to the two surfaces of each, skin or hide, 
 as it is desirable it should do. In each figure of the 
 drawings the same letters are used to refer to the same parts. 
 In Fig. 35, a a is a pit of the ordinary construction, and 
 in place of having the hides or skins placed on each other 
 in the liquor, they are separated by means of frames b b, 
 which are of wood, and each frame simply consists of a 
 quadrangular frame with crossbars, there being blocks, b' ', 
 to keep the frames separate, so that a skin or hide placed 
 
 Fig. 35. 
 
 between any two frames, b, will not press on a skin or 
 hide below, nor will it be pressed on by the skins or hides 
 above ; thus leaving each hide free to be acted on by the 
 tanning liquor in every part of its surfaces, which will be 
 found of great benefit in tanning hides and skins, and the 
 process of tanning may be greatly quickened ; and although 
 a pit will contain less hides or skins by these means than 
 when tanning in a pit in the ordinary manner, yet more 
 hides and skins may be tanned in a pit in a given time 
 than heretofore. In using this part of the process, the 
 workman will withdraw the hides or skins from the pit 
 from time to time, and submit them to fresh liquors, 
 according to his judgment, as usual. The hides or skins 
 
LEATHER MANUFACTURE. 
 
 with, the frames are first placed in a pit, and the liquor is 
 then run or pumped into the pit. Fig. 36 is a ground 
 plan of the frame. 
 
 The inventor states that the frames or partitions may be 
 made of copper or any other material, instead of wood, 
 and the hides separated by means of wire or network of 
 twine, or twigs, and also by bars of any other material, 
 and by any other means to which the principle of the 
 invention can be applied. Although he considers it is 
 
 
 a 
 
 
 
 
 
 
 
 
 
 
 
 
 
 "1 
 
 l> 
 
 
 
 
 
 
 
 
 
 
 P 
 
 
 
 
 • 
 
 
 
 
 , 
 
 
 
 
 J) 
 
 
 
 
 
 
 
 
 ?> 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Fig. 36. 
 
 better that each hide or skin should be by itself, yet there 
 may be two or more placed between each pair of frames 
 or partitions, but he believes there will be proportionately 
 less beneficial effect from this arrangement ; and although 
 he prefers that the skins or hides, with the frames, should 
 be in a horizontal position, yet the system of keeping the 
 hides separate may be carried out by using frames such as 
 c c, Fig. 37, and fastening or lacing the hides or skins 
 thereto by lacing threads d d, as shewn, the frames e 
 having blocks c, to keep them separate. Fig. 38 is a plan 
 of the same. 
 
 He next describes the second part of his invention, 
 which has for its object the pressing the spent liquor out 
 of hides or skins before again submitting them to tanning 
 liquor, and consists of using a suitable press, between the 
 
TANNING PROCESSES. 
 
 surfaces of which a number of hides or skins are piled, and 
 then pressure is exerted to bring the pressing surfaces, e, 
 
 Fig. 37. 
 
 f, of the press to approach each other, and thus to express 
 the liquor therefrom. The drawings (Figs. 39 and 40) 
 show one description of press — a screw-press, where the 
 
 Fig. 38. 
 
 pressure is obtained by means of a screw g, acting on the 
 surface e, and the other press (Figs. 41 and 42) is worked 
 
LEATHER MANUFACTURE. 
 
 by means of a roller h, and cords i i, as will readily be 
 traced on examining the drawings. These or other presses 
 
 Fig. 39. 
 
 may be employed, the invention consisting of piling a num- 
 ber of skins or hides between two suitable pressing sur- 
 
 Fig. 40. 
 
 faces, and applying pressure thereto, so that the spent 
 liquor therein may be expressed, and the skins or hides 
 rendered better capable of imbibing fresh tanning liquor 
 when they are again immersed in the pits. 
 
 Desmond's Process. — In this process the inventor em- 
 ploys saturated infusions of oak-bark or other tanning mate- 
 rial, and when the bark is exhausted, he extracts what gallic 
 acid is left by fresh water, to which liquor he adds 10 ' 00 part 
 by measure of sulphuric acid. In this liquor the hides are 
 
TANNING PROCESSES. 
 
 203 
 
 immersed until the hair is easily removed. "When the 
 swelling is necessary, the hides are immersed in water 
 acidulated with 0*05 parts by measure of sulphuric acid, 
 
 Fig. 41. 
 
 for ten or twelve hours. The hides are then washed and 
 fleshed, and are next immersed for a few hours in weak 
 
 Fig. 42. 
 
 tan liquor, the strength of which is to be renewed when it 
 becomes exhausted, till the skin is perfectly tanned. 
 
 Burbidge's Process. — The inventor treats the hides 
 with the extract of oak-bark, which he says he obtains 
 without loss of tannin. He regulates the use of this extract 
 by the barkometer. He commences with a weak extract 
 at 3°, the strength of which is increased successively by 
 changing the liquor three times a week, carrying it to 20°, 
 the strongest liquor being used when the tanning is near 
 completion. By this process the weight of the leather is 
 
204 LEATHER MANUFACTURE. 
 
 increased. While by the ordinary process it takes a year 
 to tan a hide weighing 80 lbs. when green, and which only 
 weighs 40 lbs. when tanned, by this process it is said a 
 similar hide can be tanned in three months, and it will 
 weigh 40 lbs., which demonstrates that the excess of time 
 employed is injurious to the leather. The amount of oak- 
 bark used in this process does not exceed that of the older 
 methods, being about four or five pounds for every pound of 
 leather. 
 
 Kleman's Process. — Oak-bark, such as is used in tanning 
 skins, is usually taken off while the tree is in sap. It is 
 dried in order to preserve it, and it is introduced into the 
 tanning-pit at the same time as the skins, together with 
 the requisite quantity of water. But it will be understood 
 that the tanning property as well as the chemical composi- 
 tion of the bark must vary according as the drying is quick 
 or slow, and the greater or lesser period of time during 
 which the bark is allowed to be exposed to dampness before 
 the tanning begins. In most cases the bark commences 
 to undergo acetous fermentation, which is completed in the 
 tanning-vats. In order to utilise the tanning principle, 
 whether obtained from oak-bark or gall nuts, to the best 
 advantage, M. Kleman recommends the following method 
 of procedure. The bark, while still fresh, is to be reduced 
 to small pieces and placed in a cask, and sufficient water 
 added to cover the material. The cask is then to be her- 
 metically closed, so as to prevent the action of the oxygen 
 of the atmosphere. The mixture is to be left undisturbed 
 for a few weeks, so that the principles soluble in water 
 may become thoroughly dissolved ; after this the liquor is 
 to be separated from the bark. If the liquor be now heated 
 to from 113° to 115°, it will enter into vinous fermentation, 
 and will then contain enough alcohol to mark 1° to 2°. If 
 a skin be placed in this solution, it will become very quickly 
 tanned, but will be hard and horny, owing to the concen- 
 trated condition of the liquor. If, however, it be diluted 
 with water, excellent results will be obtained, and skins 
 tanned in it will be more supple and the grain closer than 
 when tanned by the ordinary method. Moreover, by this 
 
TANNING PROCESSES. 2 °S 
 
 method the same quantity of bark -will produce more tanning 
 matter. It is not advisable to boil the bark in water, 
 because boiling coagulates the albuminous matter, which 
 induces fermentation. The inventor has assured himself, 
 by experiments, that bark which has undergone vinous 
 fermentation gives much better results than that which has 
 been subjected to acetous fermentation. 
 
CHAPTER XT. 
 
 TANNING BY PRESSURE. 
 
 Spilstrary's Process. — Drake's Process. — Knowlys and Duesbury's Pro- 
 cess. — Fryer, Watt, and Holmes's Process. — Mouren's Process. 
 
 The readiness with which tannic acid combines with 
 the unhaired skin causes its exterior surfaces to become 
 almost immediately converted into leather after immersion 
 in the tanning liquor, by which the absorbent power of 
 the skin is considerably weakened, and the interior fibres, 
 in a degree, protected from the action of the tan. To 
 overcome this drawback, and to favour the chemical 
 action of the tannin throughout the entire substance of 
 the hide, Spilsbury devised a mechanical method, for 
 which he obtained a patent in 1823, by which the tannin 
 was forced, by hydrostatic pressure, through the pores of 
 the skin, and thus its perfect conversion into leather was 
 ensured. The process is as follows : — 
 
 Spilsbury's Process. — The hides are unhaired and 
 fleshed in the usual way, after which they are carefully 
 examined, and if any holes are discovered these are 
 carefully sewn up, so that the skins may be water-tight. 
 Three wooden frames, of equal dimensions, are fitted to 
 each other, and the edges of the frames secured together 
 by screw-bolts. A skin is now laid upon one frame and 
 stretched over its edges ; then the second frame is placed 
 upon it, so that the edges of the two frames may pinch 
 the skin all round and hold it securely ; another skin is 
 then stretched over the upper surface of the second frame 
 in a similar manner, and a third frame being placed over 
 this, confines the second skin. The three frames are then 
 
TANNING BY PRESSURE. 207 
 
 pinched together and secured tightly by the screw-bolts 
 passing through ears set round their outer edges ; by this 
 means the skins are fixed so as to be operated upon by the 
 tanning infusion. The space thus formed is of the 
 nature of a bag, and is for the reception of the tanning 
 liquor, which is introduced as follows : The frames being 
 set upright, a pipe connected with a cistern above con- 
 veys the tanning infusion to the hollow space or bag- 
 formed by the two skins. The air is allowed to escape 
 by a stopcock below, which is closed when the tanning 
 liquor is introduced. The stopcock connected with the 
 cistern-pipe is kept open when the bag is filled to allow 
 the hydrostatic pressure to force the tanning liquor 
 through the pores of the skin by slow infiltration, whereby 
 the tannin is brought in immediate contact with its fibres. 
 The effect of the pressure shows itself by a continual 
 sweating of the tanning liquor at the outer surfaces 
 of the skins. "When the tanning is found to be complete, 
 the upper stopcock is closed, and the lower cock opened 
 to allow the liquor to run off. Finally, the frames are 
 shifted, the bolts unscrewed, and the pinched edges of 
 the skins cut off, after which they are dried and finished 
 in the usual way. 
 
 Drake's Process. — The above process was followed, in 
 1831, by a patent by William Drake, a tanner, of Bed- 
 minster. By this process the hides were in the first 
 instance immersed in a weak tan liquor, and frequently 
 handled in the usual manner, by which they became par- 
 tially tanned before being submitted to the infiltration 
 process. Two hides, as nearly as possible of the same size, 
 were then placed with their grain side in contact, and the 
 two edges were carefully and firmly sewn together by 
 means of shoemakers' waxed thread, by which a bag cap- 
 able of holding tan liquor was formed. This bag was 
 then suspended by loops, sewn to its shoulder ends, upon 
 pegs in such a way that it could hang within a wooden- 
 barred rack, and its sides pressed together in a book form. 
 The upper end of this bag was left unstitched to the extent 
 of about an inch, so as to admit a funnel, through which 
 
208 LEATHER MANUFACTURE. 
 
 cold tan liquor was poured until the bag was full. After 
 a certain time, dependent upon the texture of the hides, 
 the outer surface of the bag assumed a moist or sweaty 
 condition, and drops would begin to appear at the bottom 
 of the bag, which were received in a vessel placed beneath. 
 The liquor thus collected was from time to time returned to 
 the bag, and a constant supply of pure tan liquor also 
 introduced into the funnel, so that the bags were always 
 full. When the hides became hard and firm, while being 
 uniformly damp from the exudation of the tan liquor, 
 the temperature of the apartment, which had been kept 
 well ventilated, was next heated gradually to from 70° to 
 150° Fahr., and the heat was kept up until the hides 
 became harder and firmer in every part. As soon as the 
 hides assumed black patches in places, and the tanning 
 liquor ceased to diminish in strength, the tanning was 
 found to be complete. The liquor was then run off by 
 cutting a few stitches at the bottom, and the edges of the 
 hides were then pared, and they were dried and finished 
 in the ordinary way. To prevent the wooden bars within 
 the rack from disfiguring the hides, the bags were occa- 
 sionally shifted a little sideways. It is stated that by this 
 process hides cotdd be as perfectly tanned in ten days as 
 in as many months by the ordinary methods. 
 
 Knowlys and Duesbury's Process. — By this process 
 the hides are suspended in an air-tight vessel of rather 
 larger capacity than their dimensions, and for this purpose 
 it is lined with hooks, upon which the hides are hung at 
 regular intervals, and kept expanded by means of weights 
 attached to their lower ends. In the upper portion of the 
 vessel or vat is an opening with a movable cover, for the 
 entrance of the workmen. In the side, near the top, is a 
 tube with a stopcock and coupling screws, for connection 
 with an air-pump, and in a corresponding position, on the 
 opposite side, is a similar tube for the admission of air, to 
 create external pressure, if required. The tanning liquid 
 having been introduced until it covers the hides, the vessel 
 is hermetically closed, and then exhausted of air by means 
 of the air-pump. As soon as the vacuum is established, 
 
TANNING BY PRESSURE. 209 
 
 the contents of the vat are kept in repose for a day and 
 night, after which the tanning liquor is drawn off, and the 
 apparatus allowed to remain empty for two or three hours 
 to permit the admission of air. This manipulation is re- 
 peated several times, or until the hides are sufficiently 
 tanned. The ooze must be renewed after each exhaustion 
 of the vessel, and the first liquid should be weak, but as 
 the operation proceeds its strength must be gradually 
 increased. This means of promoting hydrostatic pressure 
 by the aid of a vacuum is stated to greatly accelerate the 
 impregnation of the hides with tannin, and the process is 
 said to be eligible both as regards quality of leather and 
 economy of time and labour. The air being withdrawn 
 from the pores of the skin, its resisting action, which pre- 
 vents the rapid penetration of the ooze with the skin, is 
 overcome. 
 
 Pryer, Watt, and Holmes's Process. — The object of 
 this invention is to tan skins and hides by hydraulic 
 pressure, which is effected as follows : — The patentees 
 say, " We employ round upright tanks, to be made air- 
 tight, and sufficiently strong to bear a pressure of from 
 10 to 12 lbs. to the inch, according to the time intended to 
 be given in the process of tanning. These tanks are to be 
 fitted internally with laths or hoops, or both, to attach 
 each skin to separately at its full length ; the internal fit- 
 tings of the tank to move upon centres, so that the skins, 
 when once placed in the tank, will not have to be taken 
 out until thoroughly tanned. The skins or hides having 
 been arranged in their places, the hydraulic pump is then 
 set to work, which forces the bark liquor (such as is used 
 in the old process) into the tanks up to the required 
 pressure. The bark liquor being now in the tanks, the 
 fittings, with the skins, should be moved about four times 
 a day for the first three or four days ; at the end of that 
 time to be moved twice a day, and at the end of the fifth 
 day once, until thoroughly tanned. The liquor is then 
 to be drawn off, the skins removed and others substituted 
 for them, to be treated in like manner." 
 
 Mouren's Process. — By this method a vessel, capable of 
 
 P 
 
2io LEATHER MANUFACTURE. 
 
 withstanding the pressure it is to be subjected to, is lined 
 with lead, and it is furnished with manholes in the cover, 
 which are made to screw on and off. Connected with, or 
 standing upon, a vat containing tanning liquid, are placed 
 two pumps, one communicating with the upper part of the 
 vessel, and the other opening into a channel running up 
 and down the side of the vessel, and which is perforated. 
 The skins are placed in the vessel between two layers of 
 tan ; tanning liquid is pumped into the vessel at the upper 
 part, and the entire vessel is filled ; the pump communi- 
 cating with the perforated channel is then used to force in 
 more tanning liquid to any required pressure, which is 
 denoted by a gauge on the pipe leading into the channel. 
 The skins or hides are kept under pressure for periods 
 varying with their nature and the purposes to which they 
 are to be applied. The operation may be performed once 
 or of tener. 
 
CHAPTER XYI. 
 
 QUICK TANNING. 
 
 Quick Tatyiing. — Dr. Ure'a Views. — Dussauce's Observations. — Dietz's 
 Process. — ISTeedham's Process. — Nuessly's Process. — Bell's Process. — 
 Baron's Process. — Another Quick Process. — Guiot'a Process. — Danish 
 Quick Process. 
 
 Quick Tanning. — "When we consider that by the old pro- 
 cesses of tanning the conversion of hides and skins into 
 good leather — and it was good — frequently occupied a 
 period of about a year and a half, it is not to be wondered 
 at that attempts should have been made to reduce the time 
 required for perfect tanning by other means than those 
 ordinarily adopted. In these days, with our greatly in- 
 creased population and vast export trade, if we were de- 
 pendent upon the old slow processes of manufacture, and 
 upon oak- bark alone, how many of the industrial popula- 
 tion would be compelled to go barefoot ! 
 
 It has often been remarked that science has done less to 
 improve the tanning art than has been the case with many 
 other chemical industries. This is doubtless true to a 
 certain extent ; but it cannot be denied that from the 
 moment the principles of the art were discovered and 
 explained, commenced that great change in the modus 
 operandi which has ever since been working, by slow 
 degrees it is true, to develop a more speedy yet equally 
 good method of tanning than that pursued up to the 
 latter part of the eighteenth century. That the process 
 of tanning can never be both quick and good, has been 
 demonstrated by long years of experience almost beyond 
 the shadow of a doubt. But that there is a mean between 
 
212 LEATHER MANUFACTURE. 
 
 the very quick and the very slow methods, which has now 
 been arrived at, must, we think, be admitted. 
 
 That the conversion of gelatine into leather, or rather 
 into i anno -gelatine, is not of itself a slow process is proved 
 by the avidity with which that substance combines with 
 tannin the moment these substances come in contact with 
 each other ; but, in the case of a hide immersed in tan- 
 ning liquor, when once this effect has taken place upon 
 its superficial surfaces, its powers of absorption — no matter 
 to what extent the pelt may have been raised or swollen — 
 are materially diminished, and before the tannin can find 
 its way to the interior fibres of the skin it must of 
 necessity remain for a lengthened period in the tanning 
 liquor. JSTow it might naturally be thought that if by any 
 plan the tan liquor could be forced throughout the entire 
 structure of the skin, and thus all its fibres brought in 
 direct contact with the astringent principle, that the 
 operation of tanning would be rendered an almost instan- 
 taneous process. But is this so in fact ? "We know that 
 by Spilbury's and Drake's ingenious processes the tannin 
 was forced through the skins by hydrostatic pressure, until 
 it eventually appeared on the external surfaces in the form 
 of a perspiration ; but though this would unquestionably 
 prove that the astringent matter had permeated the entire 
 structure of the skin, would not the conditions under which 
 the tannin was introduced keep the shin porous when the 
 operation was complete ? Would even the after process of 
 drying — which would naturally close the pores to some 
 extent — enable the leather to acquire that hardness, firm- 
 ness, and absence of porosity which slowly tanned leather is 
 known to possess ? In other words, although skins tanned 
 by hydrostatic pressure would shrink and become more or 
 less compact and firm after drying, would not moisture 
 again dilate the pores when, say, boot- soles made from such 
 leather were subjected to the effect of wet ? In the 
 ordinary slow process of tanning the expansion of the 
 pores, beyond that which is induced by the process of 
 raising, would not take place, but rather, by the weight 
 of hides and tan in a well-filled pit, the pores of the skin 
 
QUICK TANNING. 213 
 
 would be more likely to become closed to some extent 
 ichile the skin was wet, and would become still more con- 
 tracted during the after process of drying. 
 
 We would ask, does not the process of tanning mean 
 something more than the mere conversion of the gelatine 
 of the hide into the chemical substance called tanno-gela- 
 tine ? As Sir Humphry Davy believed to be the case, does 
 not the slow absorption of vegetable extractive constitute 
 an important and necessary feature in the formation of 
 leather ? And if so, may not the union of gelatine, tannin, 
 and vegetable extractive be naturally a slow process ? If 
 this be the case, we have merely to determine how long the 
 process actually takes under the most favourable conditions. 
 The actual period may be far short of the time allotted to 
 the process by the old tanners — as it would naturally be 
 when ooze is employed instead of water with the tan 
 stratified with the hides ; on the other hand, allowing 
 for the advantage in speed which liquid tan must pre- 
 sent, the period necessary to convert hides into perfect 
 leather may naturally, under the most favoured conditions, 
 be slow. 
 
 Dr. Tire's Views. — Upon this subject Dr. Ure makes 
 the following important observations, and his reasoning, 
 based upon Sir Humphry Davy's expressed views on the 
 one hand, and the experience of practical workmen on the 
 other, clearly indicates that not only is vegetable extrac- 
 tive a necessary constituent of leather, but that its union 
 with the gelatine of the skin and tannin is essentially a 
 slow process. " When calf-skin is slowly tanned in weak 
 solutions of the bark, or of catechu, it combines with a good 
 deal of extractive matter ; and though the increase of the 
 weight of the skin be comparatively small, yet it has be- 
 come perfectly insoluble in water, forming a soft but at the 
 same time strong leather. The saturated infusions of 
 astringent barks contain much less extractive matter in 
 proportion to their tannin than the weak infusions ; and 
 when skins are quickly tanned in the former they produce 
 a worse and less durable leather than when tanned in the 
 latter. In quick tanning a considerable quantity of 
 
214 LEATHER MANUFACTURE. 
 
 vegetable extractive matter is thus lost to the manu- 
 facturer, which might have been made to enter as a useful 
 constituent into the leather. These observations show 
 that there is sufficient foundation for the opinion of the 
 common workmen concerning what is technically called 
 feeding of leather in the slow method of tanning; and 
 though the processes of this art have been unnecessarily 
 protracted by defective methods of steeping and want of 
 progressive infiltration of the astringent liquor through 
 the skins, yet in general they appear to have arrived, in 
 consequence of old experience, at a degree of perfection 
 in the quality of the leather which cannot be far ex- 
 ceeded by means of any theoretical suggestions which 
 have been advanced." 
 
 According to the foregoing remarks, there would 
 appear to be, as we have suggested, an exact point, per- 
 haps now determined, when the tanning process is known 
 to be complete, without unnecessarily protracting the 
 operation on the one hand, or unduly hastening it on 
 the other. The tanning strength of the liquors being 
 always uniform (though progressively varying in propor- 
 tions of tannin), and the changes of temperature allowed 
 for and calculated, might not the actual period requisite 
 to produce a perfect leather be determined by a consecu- 
 tive series of trials ? 
 
 Dr. Ure further remarks, "On the first view it may 
 appear surprising that in those cases of quick tanning 
 where extractive matter forms a certain portion of the 
 leather, the increase of weight is less than when the skin 
 is combined with the pure tannin ; but the fact is easily 
 accounted for, when we consider that the attraction of 
 skin for tannin must be probably weakened by its union 
 with extractive matter ; * and whether we suppose that 
 the tannin and extractive matter enter together into 
 combination with the matter of the skin, or unite with 
 separate portions of it, still, in either case, the primary 
 
 * Considering the superior affinity of tannic acid for gelatine over 
 vegetable extractive, is it not the former which retards the absorption of 
 the latter '( 
 
QUICK TANNING. 215 
 
 attraction of the skin for tan must be to a certain extent 
 diminished. In examining astringent vegetables in rela- 
 tion to their power of making leather, it is necessary to 
 take into account not only the quantity they may contain 
 of the substance precipitable by gelatine, but likewise the 
 quantity and the nature of the extractive matter ; and in 
 cases of comparison, it is essential to employ infusions of 
 the same degree of concentration." 
 
 In applying any of the quick tanning processes, the 
 principles indicated in the above observations must not be 
 lost sight of, while the practice must be in accordance 
 with ascertained facts ; otherwise the production of good 
 leather may be more accidental than certain, even if it 
 does not become impracticable. 
 
 Dussauce's Observations. — As to the time necessary for 
 the conversion of hides into leather, Dussauce says, " Many 
 tanners maintain that there is no advantage whatever in 
 keeping leather in process after the tannin and gelatine have 
 united. There is much diversity of opinion upon the length 
 of time necessary or advantageous to keep leather in the 
 tanning liquor, but it doubtless depends very much upon 
 the preparation of the hide. Tanners generally do not 
 pay proper attention to the early steps, those of unhairing 
 and raising. Is there any necessity that time be given 
 after the tannin and gelatine have united for leather to 
 consolidate and grow ? Is there any gain in weight, if 
 even made more durable by the delay ? " According to 
 Ure's views, and the observations of the practical work- 
 men to whom he has referred, an affirmative answer must 
 be given to these two questions, if by "feeding the 
 leather," we are to understand giving the hides sufficient 
 time to take up as much vegetable extractive as they are 
 capable of doing, and which, in a sense, would be allow- 
 ing the leather to grow or its weight to become increased 
 by the slow process necessary for the absorption of 
 vegetable extractive. 
 
 Again, Dussauce asks, " What length of time is it 
 necessary to let hides tan which are limed or sweated in 
 the common method ? These are questions often asked, 
 
S*6 LEATHER MANUFACTURE. 
 
 and on which the views of practical men are desired. The 
 fact is, that when the tannin and gelatine are completely 
 united, the process of the formation of leather is ex- 
 hausted." 
 
 If vegetable extractive were not, as it has been proved 
 by Davy to be, a necessary constituent of solid leather, 
 this statement of Dussauce might be fully accepted ; but 
 we unhesitatingly give the preference to the views of Davy 
 and TJre, because we believe that leather, properly so 
 called, is a compound of gelatine, tannin, and vegetable 
 extractive, and not merely tanno- gelatine. " But in the 
 ordinary manufacture," Dussauce continues, " it is never 
 the case that the hide has received all the tannin [and 
 extractive ?] of which it is capable, and therefore the 
 extension of time is followed by an increase of weight. 
 If all the gelatine of the hide could be exposed at the 
 same moment to the action of the tannin, the process 
 would be instantaneous." True ; but the product would 
 be tanno-gelatine and not leather proper. " There is no 
 doubt that the improvements in this direction [quickening 
 the tanning process] are feasible, and that a considerable 
 time is now actually gained over the old periods of 
 manufacture without any injury to the leather. But no 
 improvement has yet so facilitated the quick production of 
 leather that a material gain in weight may not be secured 
 by a protracted stay in the vats ; while attempts of this 
 kind, by the use of deleterious substances, have resulted 
 in rotting the fibre of the hide. Has there ever been any 
 leather tanned in two, three, or six months, by any 
 patented process, which has claimed to be equal to 
 English bark leather? And what gives the great superior- 
 ity of this class of leather, if not the length of time it is in 
 the tan ? " Undoubtedly a protracted exposure to the 
 tan would give the superiority referred to, but is it not 
 due to the vegetable extractive, and not the tannin, 
 entering into the substance of the hide after the gelatine 
 of the skin has become converted into tanno-gelatine ? 
 Does not the term " feeding " the leather really mean 
 allowing time for the hide to take up as much vegetable 
 
QUICK TANNING. 217 
 
 extractive as it is capable of doing, whereby not only is 
 its weight increased but its quality improved ? * 
 
 "It is well known," says Dussauce, " that the oak 
 tanners of Pennsylvania and Maryland are about twice as 
 long in tanning leather as the hemlock tanners. May it 
 not be this length of tanning which gives the general 
 superiority to oak leather? It is a general complaint 
 that leather tanned by quick processes is wanting in solidity 
 and strength. It is porous, easily filled with water, and 
 wanting in durable qualities." These observations, like 
 those from the same authority previously quoted, tend 
 materially to strengthen the views propounded by the 
 gifted observer Davy, to whose clear and original mind 
 we are indebted for so much that is valuable both to 
 science and to art. 
 
 "We have been tempted to dwell thus far upon the 
 comparative advantages and disadvantages of the slow and 
 quick methods of tanning, in order that the reader, bearing 
 in mind the support which practice has given to theory, 
 may more readily form his own judgment upon the 
 merits of the various processes which will hereafter be 
 submitted to his consideration. 
 
 Dietz's Process. — The object of this invention is to 
 swell the tissues and fibres of the skin previous to, and 
 during the process of tanning, by the employment of 
 saline liquors, whereby the skin is stated to be more 
 readily affected by the tanning material ; and in using in 
 connection with such saline liquors tanning liquors of 
 different and increasing strength, by which the centre 
 and inner parts of the skin are tanned as quickly, or 
 nearly so, as the outer surfaces. The inventor makes a 
 weak liquor, at 2° or 3° of the barkometer, from any 
 tanning material. In this liquor he mixes salt or alum in 
 the proportion of two ounces to the gallon, and combines 
 the whole by well stirring. The skins are immersed in 
 this liquor and handled till they are saturated and the 
 fibre fully swollen. The saline substances may be dissolved 
 in water alone, without any tanning material, and the 
 * And -which would not he attained if tan liquor only were used. 
 
2i8 LEATHER MANUFACTURE. 
 
 skins saturated with, this liquor, and after complete satura- 
 tion they are passed into the tanning bath. The strength 
 of the bath is to be increased from 2° to 4° every day, and 
 the skins stirred and handled until they are tanned. The 
 time required for tanning by this process is — 
 
 For sheep skins 2 or 3 days. 
 
 „ calf skins 8 days. 
 
 „ heavy leather 30 to 40 days. 
 
 ,, sole 40 to 50 „ 
 
 Needham's Process. — In carrying out this process a 
 bath is prepared consisting o£ — 
 
 Hempseed 1 peck. 
 
 Hops : 1 lb. 
 
 Sal soda (soda crystals) \ „ 
 
 Animal brain i 
 
 4 >> 
 
 The whole of the above are boiled in 8 gallons of water, 
 and when ready is to be diluted with 40 gallons of water. 
 The hides are soaked in this solution from six to thirty- six 
 hours. They are put into a tanning solution composed of — 
 
 Catechu 12 lbs. 
 
 Divi divi 4 ,, 
 
 Alum 4 „ 
 
 Salt 2 „ 
 
 The novelty in this process consists in treating the 
 hides in the above solution preparatory to immersing them 
 in the tanning liquor. 
 
 Muessly's Process. — The inventor first makes a solu- 
 tion composed of — 
 
 Pyroligneous acid (wood vinegar) 1 gallon. 
 
 Water 3 gallons. 
 
 Hydrochloric acid 4 ounces 
 
 Catechu If lb. 
 
 Alum f lb. 
 
 The whole of these are to be well mixed together by 
 stirring. To 100 gallons of the above solution he adds — 
 
 Catechu 40 lbs. 
 
 Alum 10 lbs. 
 
QUICK TANNING. 219 
 
 The hides are to be immersed in this bath, when in 
 three or four days they will be tanned. Heavy hides 
 require three or four weeks. 
 
 Bell's Process. — The hides being unhaired and prepared 
 as usual, are to be immersed in tanning liquor from two 
 to four days. The tanning liquor is composed of — 
 
 Wood-ashes 1 bushel. 
 
 Water 50 gallons. 
 
 After settling, draw off 40 gallons ; to this is added 
 40 lbs. of terra japonica, and the whole boiled until the 
 latter is dissolved. When cold, the solution is ready 
 for use. The inventor says that by the combination 
 of the alkaline ley and tannin he is enabled to prevent 
 the tanning liquors from becoming sour or decomposed, and 
 he is enabled to strengthen them without accumulating 
 more than is necessary, and the skins will tan in a shorter 
 time and with less labour than by other processes. 
 
 Baron's Process. — By this process the hides are pre- 
 pared in the usual manner, excepting that they are soaked 
 for three or four hours in river water, containing yVo 0" °f 
 hydrochloric acid, to neutralise any lime present in the 
 skins ; they are afterwards washed in river water. This 
 treatment with the dilute acid completes the perfect swel- 
 ling of the hides, and they are ready for tanning. Before 
 tanning, however, the colour of the leather must be fixed, 
 so as to be of the usual shade. For this purpose an 
 infusion of oak- bark at 1° by the barkometer is taken, and 
 to which -y^-o of madder is added. The hides are immersed 
 in this bath for six hours, so that the colour may be uni- 
 form. They are left to rest for an hour, then turned over 
 every hour. After twenty- four hours the hides are ready 
 for tanning in the following manner : Dissolve catechu in 
 river water, according to the number of hides to be 
 tanned. The liquor is placed in a receiver covered with 
 a filter and provided with a " rubber " pipe to transfer 
 the liquor to the vats. The first vat contains liquor at 1°, 
 with a weak solution of alum. Into this the hides are 
 placed, and are occasionally stirred during the first two 
 
220 LEATHER MANUFACTURE. 
 
 hours ; afterwards they are handled every three hours. Next 
 day they are placed in a vat containing liquor at 2°, and 
 handled four times a day, then allowed to drain two hours. 
 The strength of liquor is to be increased from day to day, 
 until the hides are well tanned, when they are finished in 
 the usual manner. 
 
 Another Quick Process — To carry out this process 
 air-tight copper vessels are used. When the hides are 
 taken from the washing water the moisture is expelled by 
 pressure ; the hides are then packed in a drum fixed so 
 as to have a rotary motion, and with them the necessary 
 amount of tanning material is mixed, together with suffi- 
 cient water to keep the contents of the vessel moist. The 
 main hole of the drum is now closed, and the air pumped 
 out as completely as possible. , This being done, the stop- 
 cock is closed and a piece of lead pipe is added to the 
 conducting tube. This lead pipe communicates with a tank 
 containing tanning liquor of proper strength. If the 
 stopcock be now opened, the tanning liquor rushes rapidly 
 into the drum, and when a sufficient quantity has been 
 admitted the stopcock is closed and the drum rotated for 
 an hour, or half an hour, according to the quantity of hides 
 contained in it. After two or three hours' rest the 
 rotation is again resumed, and continued until the operation 
 is complete. The advantages of this process are said to be 
 that the pores of the skins are opened, and the tannin is 
 not so quickly converted into gallic acid. The rotary 
 motion facilitates the solution of the tannic acid of the 
 bark, and helps its absorption by the hides, which are 
 tanned in less time than without rotary motion. The 
 following table shows the time occupied in tanning with 
 and without rotary motion : — 
 
 Without rotary motion 
 
 Calf skins from 6 to 11 days 
 
 Horse hides 35 to 40 days 
 
 Lighter hides 30 to 35 days 
 
 Middling cow hides^ 40 to 45 days 
 
 Heavy cow hides 50 to 60 days 
 
 Ox hides, light 50 to 60 days 
 
 Ox hides, first quality 70 to 90 days 
 
 With rotary motion. 
 . 4 to 7 days 
 
 . 14 to 18 days 
 
 . 12 to 16 days 
 
 . 18 to 20 days 
 
 . 22 to 30 days 
 
 . 20 to 30 days 
 
 . 35 to 40 days 
 
QUICK TANNING. 221 
 
 By the above process a large percentage of bark is said 
 to be saved. 
 
 Guiot's Process. — The bides are depilated and raised as 
 usual. Fifty bides are tben treated in a vat of tbe fol- 
 lowing dimensions : width 3 feet, and height 4J feet. 
 The proportions of materials used for fifty hides are — 
 
 Catechu 150 lbs. 
 
 Water 50 gala. 
 
 Stir well until dissolved, and add 50 gallons of fresh 
 water, and a solution containing 3 lbs. of lime ; mix well 
 together. The hides are to be immersed in this bath for 
 eight weeks. During the first two weeks they are to be 
 handled once a day ; the last six weeks they are to be 
 handled only once a week. Another bath is to be prepared 
 by taking 25 gallons of the above liquid which has been 
 used, and adding to it 25 gallons of fresh water and 6 lbs. 
 of white vitriol (sulphate of zinc). These are to be mixed, 
 and the hides placed in this bath for four days, with stir- 
 ring every day. The hides are then removed and put into 
 125 gallons of fresh water, in which they are left for three 
 days, when the operation is complete, and they are finished 
 as usual. 
 
 Danish Quick Process. — The following rapid method 
 of tanning, by which "dressing leather" may be tanned 
 in two months, is practised in Brittany and elsewhere. 
 The skins are first unhaired and fleshed as usual ; they 
 are then coloured by being barley and tan dressed, like 
 barleyed skins, after which they are sewn up in the form 
 of bags, apertures of about ten inches in length being 
 left, through which they are filled with tanning solution. 
 These openings being then sewn up, the closed bags are 
 forcibly beaten all over for the purpose of distributing 
 their contents equally throughout. They are then deposited 
 in pits containing sufficient ooze to cover them completely, 
 these pits being 4^ feet deep, the same width, and 8^ to 
 10^ feet long. When submerged in the pits, planks 
 heavily weighted with large stones or weights are placed 
 upon the skins, so as to press them down forcibly towards 
 
222 LEATHER MANUFACTURE. 
 
 the bottom, to increase the penetrating power of the in- 
 fusion ; and in order that they may be equally tanned on 
 their different sides the planks are removed three or four 
 times a week, and the bags are again thoroughly beaten 
 and their position changed. 
 
 Skins prepared in this way are supple and pliable like 
 crop leather, and have a finer colour than strong leather, 
 but they are thinner than those made in the ordinary way, 
 owing to their not swelling up by the slow process of 
 feeding, and also from the pressure from within and 
 without to which they have been subjected. " It is 
 possible," says Morfit, " that the improvement of this 
 process, which is now the old method combined with that 
 devised by Seguin, may offer many advantages. The 
 external and internal pressure mutually assisting, must 
 certainly promote the introduction of tannin and extractive 
 into the tissue of the skin. It is, however, doubtful if 
 the durability and other qualities of the product are equal 
 to those of leather prepared by more tedious processes" — 
 an observation which is more or less applicable to eveiy 
 other process of quick tanning. 
 
CHAPTEE XVII. 
 HARNESS LEATHER TANNING. 
 
 Harness arid Upper Leather.— Crop Leather. 
 
 Harness and Upper Leather. — The preparation of 
 leather to be dressed for harness and boot uppers is in 
 many respects different from that adopted for butt or sole 
 leather ; and, as will be readily understood, it must possess 
 the utmost degree of toughness and strength which it is 
 possible to obtain by the most careful means, from the first 
 selection of the hide to the last operation of finishing. 
 Although dry salted and dry flint hides may sometimes be 
 employed for dressing purposes, there can be no doubt that 
 the best hides for this class of leather are the recently 
 flayed hides as they come from the slaughter-house. Hides 
 which have been badly flayed, branded, or pitted with 
 warble marks should be rejected. The hides employed for 
 harness purposes are those of cows and smaller oxen. 
 
 Selection of Sides. — " A perfect hide for dressing pur- 
 poses should be thoroughly flayed, free from warbles or 
 warble marks, of a close, fine, glossy grain, without any 
 scratches or brands, and well filled and level throughout. 
 Now many hides may have all the first qualities, and 
 may be full and plump at the back, but fall away at the 
 shoulders, and nothing makes a more imperfect trace or 
 rein if it is not of the same substance throughout. 1 
 know it is most difficult to get hides with all the requisites 
 mentioned, but the only way is for the tanner to buy as 
 many as he possibly can at the proper season of the year, 
 
224 LEATHER MANUFACTURE. 
 
 go to market where he gets the best selection, and go over 
 the lots or piles of hides himself, feeling along the shoul- 
 ders and neck, and only purchasing the lots where the 
 fewest flat or thin hides are." * 
 
 Washing and Cleansing. — The hides are thrown into a 
 pit containing clean water, to remove the blood, dung, 
 and dirt, in which they remain for twenty-four hours. 
 They are then drawn, and the horns and tail removed, 
 after which they are again steeped for twenty-four hours. 
 Dried and salted hides, however, require a much longer 
 soaking, and must be effectually and thoroughly cleansed 
 and softened before going into the lime. Old bate liquor 
 is recommended as a good soak for dried and salted hides 
 and kips. In former days some of the Leeds kip tanners 
 considered this old soak so valuable that they worked it 
 for many months without throwing it away. The fulling 
 stocks are much employed for the softening of dried kips, 
 and the beating action of the stocks, alternated by soaking, 
 will generally bring them to nearly the condition of fresh 
 hides in the course of a week or ten days. 
 
 Liming. — The method recommended by " an old Scotch 
 Tanner " is as follows : " The hides being thoroughly 
 washed and cleaned in the water pits, are drawn up and 
 piled one on the top of another, hair upwards, next to 
 No. 1, or the weakest lime pit. The lime liquor in the 
 pit must be plunged with a plunger to raise the lime 
 from the bottom, the hides thrown in, two men working 
 at the hides and two men carefully laying them out and 
 putting down with sticks. I allow them to lie for twenty- 
 four hours in No. 1, or weakest lime pit, and draw them 
 next morning, great care being taken not to scratch the 
 grain of the hide with the hook. Ten hides are thrown 
 aside from the top of the pack, and are put at the bottom. 
 The hides are then put into No. 2 lime, which should 
 be a little stronger than No. 1, spreading them out as 
 was done previously. I allow them to lie in No. 2 lime 
 twenty-four hours, then draw them and put them into 
 No. 3 lime, changing ten hides again from the top to the 
 * Scottisli Leather Trader. 
 
HARNESS LEATHER TANNING. 225 
 
 bottom of the pack. No. 3 lime should be stronger than 
 No. 2, and so on in succession, the last lime being the 
 strongest and newest. I draw all my hides every morn- 
 ing, transferring ten hides from the top to the bottom of 
 the pack each time, and changing them over to a stronger 
 lime till they come to the strongest lime, where they lie, 
 of course draining every morning, till they are ready for 
 unhairing. If after eight days or so I find the hair not 
 giving way, I add a little fresh-slaked lime to the liquor 
 when the hides are lying up. It is impossible to give the 
 proper quantity of lime that should be used (owing to its 
 variable quality). Every tanner, if he pays proper attention 
 to his limes, will soon find this out and regulate the 
 quantity himself. Do not allow your limes to get old or 
 stale ; the value of lime is not great, and there is far 
 more to be lost by the hide being kept in weak old limes 
 than in casting away the old lime and making fresh 
 liquors. This, I think, is one of the causes why some 
 tanners never get proper weight into their leather. The 
 time I give my hides is from ten to twelve days, when 
 they should unhair easily ; when unhaired, I throw them 
 into a pit of clean water, to remove all superfluous lime 
 that may be adhering to them, when they are ready for 
 fleshing," We think there can be no doubt as to the 
 danger of keeping hides for any length of time in ex- 
 hausted or very weak lime liquors ; and it is more than 
 probable that limes to which the term " weak " is applied 
 frequently contain little or no lime in an active or caustic 
 state, from the fact that the lime liquors are constantly 
 exposed to the action of the atmosphere, from which they 
 are continually absorbing carbonic acid, converting the 
 caustic into carbonate of lime, which can have no effect 
 upon the hides, while the liquor not being caustic would 
 naturally have the same solvent action upon the gelatine of 
 the skins as water, and would therefore reduce their weight. 
 Bating. — After liming, unhairing, and fleshing, the 
 pelts are bated in a bate of hen manure, or, according to 
 the practice of the tanner, they are treated in boric or 
 lactic acid solutions, &c. 
 
 Q 
 
226 LEATHER MANUFACTURE. 
 
 Tanning. — The pelts are treated in the handlers in the 
 same way as those intended for sole leather, except that 
 they are not kept in the old and sour liquors for a 
 lengthened period, but merely sufficiently long to " clear 
 the grain," as it is termed. They are next treated in 
 weak sweet liquors of progressive strength, the liquors 
 being returned to the leaches to be strengthened, as usual. 
 The strongest liquors in the handlers should not exceed 
 from 10° to 12°. The hides are treated in the handlers 
 for about a month or six weeks, being worked in a round, 
 after which they are placed in pits containing stronger 
 ooze and finely ground oak-bark, being worked in a 
 round as before, for two or three months, after which 
 they are stratified with ground oak-bark in the layers, 
 and treated with a still stronger ooze. After about six 
 weeks the hides are taken out, and again laid down with 
 interposed layers of ground bark and strong ooze, and in 
 these pits they remain for about two months, the process 
 being repeated once or twice more, until the tanning is 
 complete. 
 
 1 Crop Leather. — Crop leather, now almost extinct, in- 
 cluded the leather prepared from the hides of cows and 
 small oxen, the former (provided the cow has not calved) 
 yielding the strongest and toughest leather of the two. 
 As a general rule the stoutest and most compact or com- 
 pressed leather (from ox hides) is used for sole leather, but 
 not unfrequently leather made from crop hides was devoted 
 to this purpose, without being rolled and condensed by the 
 tanner, as in the case of butts. The lighter cow hides are 
 used for the uppers of stout shoes and boots, inner soles, 
 and also for water-boots, and other purposes. The hides 
 of young oxen, being deficient in firmness and thickness, 
 are chiefly used for belt leather. In the treatment of crop 
 hides, they are first submitted to the usual preliminary 
 operations, and are then placed in the lime pits until 
 ready for unhairing, which in summer is usually in about 
 eight days, and in winter from ten to fourteen days ; they 
 are then sent to the beam-house, where, after unhairing, 
 they are fleshed with great care, being frequently rinsed 
 
HARNESS LEATHER TANNING. 227 
 
 each time, in running water if practicable, to remove the 
 lime as far as possible. The hides intended for uppers 
 require at least four or five rinsings, while those which 
 are to be used for sole leather require but two rinsings. 
 They are next raised, either by immersion in dilute sul- 
 phuric or hydrochloric acid, according to the tanner's 
 practice ; and they are then placed in the handlers, in 
 weak ooze at first, in which they are handled daily in 
 the same way as butts, and are afterwards treated in 
 stronger ooze, and handled as before during a period of 
 four or five weeks. They are next put into the layers, 
 in which, they are carefully spread out, with alternate 
 layers of finely ground oak-bark; the pit is then filled 
 up with ooze. At the end of about six weeks they are 
 taken out and subjected to a fresh change of bark and 
 ooze, this being repeated once or twice more until the hides 
 are perfectly tanned. 
 
CHAPTER XVIII. 
 
 AMERICAN TANNING. 
 
 Cold Sweating of Hides. — Sweat Pits. — Treatment of Hides in the Sweat- 
 pits. — Treatment of Hides after Sweating. — LimiDg. — Unhairing by 
 Prof. Lupkin's Process. — Beam Work. — Trimming or Kounding. — 
 Grinding the Bark. — Leaching. — The " Press" Leach. — Eaising with 
 Vitriol. — Handling. — The Eocker Handler. — The Layers. 
 
 While our American cousins freely and generously 
 acknowledge the excellence of English tanned leather, 
 and highly compliment our manufacturers upon the care 
 and economy with which they conduct their various 
 operations, there is much in the Transatlantic system of 
 tanning which deserves and must command attention. 
 If, however, our great American competitors were as 
 silent upon the subject of which we are treating as are 
 our own countrymen — with few exceptions — we should 
 have but little to communicate as to the modus operandi 
 adopted in the United States. The whole fraternity of 
 tanners, however, both at home and abroad, are indebted 
 to Mr. Jackson S. Schultz, an eminent American tanner, 
 for a very clear and practical book on the manufacture 
 of leather* as conducted in the States, being the substance 
 of a long series of valuable papers contributed by him to 
 the Boston Shoe and Leather Reporter. Independent of 
 the great service which these writings must have rendered 
 his own countrymen, there is a great deal of information 
 conveyed by the pen of this astute writer which should 
 be read by all who follow the art of tanning, even though 
 they treat specially of the method adopted in the United 
 States. 
 
 * " Leather Manufacture." By Jackson S. Schultz. 
 
AMERICAN TANNING. 229 
 
 "We now purpose giving, as briefly as possible, a risumi 
 of the American system of tanning, as explained by Mr. 
 Schultz, but must refer the reader to his own admirable 
 work for more complete information. 
 
 Cold Sweating of Hides. — While in Great Britain 
 sheep skins are freed from their wool by " steam sweat," 
 as it is called, in the United States a system of cold 
 sweating is adopted for heavy hides which at present 
 is chiefly confined to that country. Schultz says, "It is 
 now demonstrated that a wooden, brick, or stone structure, 
 on the top of the ground, can be so completely protected 
 from the rays of the sun and other atmospheric influences 
 as to malce a good sweat-pit. The ice companies have 
 adopted surface structures of wood filled in with sawdust, 
 tan-bark, or charcoal between the outside clapboards and 
 the inner linings of their buildings, and this same form 
 of structure will make a most serviceable tanner's sweat- 
 pit. But since the sweat-pit is subject to greater changes 
 of atmosphere than the ice-house, it is desirable that the 
 inner lining of the sweat-pit should be of a more endur- 
 ing substance than wood. The damp but warm atmo- 
 sphere of tanners' sweat decomposes the fibres of the 
 wood very fast. On account of this liability to decay, if 
 for no other reason, the sweat-pits of the tanners should 
 be constructed of stone or brick. 
 
 Sweat Pits. — " The structures may be wholly above 
 ground, and should be so placed that a wheelbarrow may 
 be run from the floor of the beam house to the main passage- 
 way of the sweat-pit. These passages should be wide — not 
 less than 6 to 8 feet — and be so thoroughly lighted both 
 from top and ends as to make their passage by workmen 
 and employes both easy and agreeable. The height of this 
 main passage-way should extend above the surrounding 
 pits, and by this ' lantern ' construction both light and 
 air can be secured in the passage-way below. The pits 
 themselves should extend from both sides of this main 
 passage, and be connected with folding doors wide enough, 
 when fully open, to admit a wheelbarrow." 
 
 Each of such pits must be large enough to hold one 
 
230 LEATHER MANUFACTURE. 
 
 pack of hides, and high enough to allow the suspension 
 of a side doubled, with 2 feet clear above and 1 foot 
 below the hooks. The pits should be about 8 feet wide, 
 giving space for two tiers of sides and gangway for the 
 workmen. The pits should be so constructed that light 
 may enter sufficient to allow a close examination of the 
 hides without the employment of a lamp, and should be 
 kept in such a cleanly condition that any person could 
 enter the pit without soiling his clothes. Mr. Schultz 
 lays great stress on this point. The temperature of the 
 pits is kept under control by steam and cold water, which 
 are admitted through the main passage by means of 
 pipes. " A properly constructed pit should have a false 
 bottom, under which the steam may be forced, to find its 
 way, in condensed spray, up through the suspended sides. 
 This process will adequately warm the pit. When too 
 warm, cold-water maybe thrown from the mouth of a 
 sprinkler over the whole surface, and thus, in a few 
 moments, cool the whole space, and leave a desirably 
 moist atmosphere." The temperature should be main- 
 tained at from 60° to 70°, with globules of moisture rest- 
 ing on all parts of the suspended hides, which eventually 
 collect and drop from points of the hair. 
 
 The sweat-pits are covered by stout timber, above 
 which is a layer of earth about 2 feet thick, which is kept 
 well watered, so as to protect the interior from the heat 
 of the sun's rays. The sides of the pits may be protected 
 with the same object, either by means of earth or spent 
 tan. "With pits so constructed hides may be properly 
 "sweated" in from three to seven days — usually about 
 four or five if the hides are in proper condition. The 
 cold sweating process is, however, chiefly adopted for dry 
 "flint hides." Before submitting the dry hides to the 
 sweating process, they require to be softened or brought 
 to the condition of green hides by the usual methods of 
 soaking, beating, &c. 
 
 Treatment of the Hides in the Sweat-pits. — The 
 hides should be hung on the racks by tenter-hooks, being 
 suspended either from the shoulder or from the butt, but 
 
AMERICAN TANNING. 231 
 
 whichever method is adopted the same should be applied 
 to all, so as to ensure uniformity of action in the sweat- 
 pits. Since the sweating is more rapid above than below, 
 and as the thicker parts of the hide will resist the action 
 of the sweating longer than the thinner parts, it would be 
 better if the pates and butts could be suspended higher 
 than the bellies and shoulders ; but since this would in- 
 volve considerable difficulty, the same result is attained by 
 changing the position of the hides after three or four days, 
 when the process of sweating will have advanced con- 
 siderably. This operation of "assorting out," as it is 
 termed, requires great care on the part of the workmen, 
 since up'on this in a great measure depends the success of 
 the operation. This care is specially necessary at this 
 stage, since no two hides, however uniform in character, 
 will sweat exactly alike. " ISTo hour in the whole day," 
 says Mr. Schultz, "should be without a visit to the 
 advanced sweats. When a few sides give indication of 
 ' coming ' prematurely, before their proper time, the3 r 
 should be dropped to the bottom of the pit, and allowed 
 to lay in piles until their less advanced companions catch 
 up in the process of decomposition." 
 
 Treatment of Hides after Sweating. — The sweated 
 hides are next thrown into the mill for a few moments, to 
 wash away the dirt and " slime," and to rub as much of 
 the hair off as can be removed by such means. In respect 
 of this operation, however, Mr. Schultz says : " During 
 this short and damaging process two things happen — 
 
 1. The loose hair is fulled into the flesh so firmly as to 
 make it difficult to remove afterwards on the beam ; and 
 
 2. To pound out much of the gelatine of the hide, which 
 at this period is almost in a soluble condition, and will 
 part from its proper lodgment in the fibre almost as freely 
 as the slime and dirt with which the surfaces are supposed 
 to abound. Indeed, much of the substance that is regarded 
 as ' slime ' and ' dirt ' is the gelatine, which, when com- 
 bined with tannin, goes to make leather." He very 
 properly condemns the practice of fulling or milling 
 the hides after sweating, which must reduce their weight 
 
232 LEATHER MANUFACTURE. 
 
 considerably, besides disturbing the delicate structure of 
 the hide itself. The system which many intelligent 
 tanners of the States have found most practical is to 
 throw the hides as they are removed from the sweat-pits 
 into weak lime liquor for a short time, by which a slight 
 plumping or swelling of the hides takes place, and the 
 slimy condition disappears, while the hair does not attach 
 itself to the flesh as in the former treatment. He advo- 
 cates part liming and part sweating as a good method of 
 loosening the hair. 
 
 " There can be no doubt," he says, " that our American 
 system of cold sweating is calculated, beyond any other 
 known method, to make a firm, compact fibre when 
 properly used, and besides it is specially adapted to the 
 preparation of the dry hides of our continent. It only 
 remains for me to say a word on the subject of ' grease ' 
 and ' salt,' as among the hindrances which affect and 
 control the sweating of hides. All sweat tanners fully 
 understand that the salt (if the hide is salted or pickled) 
 must be fully soaked out before the hide will sweat. 
 From this, among other circumstances, is deduced the 
 inference that this process is a decomposing one, for, 
 so long as the hide is held (cured), from the presence of 
 salt, carbolic acid, and other tanning ingredients, the 
 sweats will not operate on the hide. So, too, if this is 
 covered with grease, as many of our Western and Cali- 
 fornian hides are, it will not sweat evenly, owing to the 
 presence of the grease on some portions more than others." 
 
 Liming — The method of preparing the lime liquors in 
 America is in many respects different from that generally 
 adopted in this country, one point of difference being that 
 less lime is employed than is usual here. After recom- 
 mending that the lime should be kej)t in dry and confined 
 apartments, where neither moisture nor air can reach it, 
 Schultz recommends that a half hogshead should be 
 placed near the lime- vat which has to be replenished. For 
 a pack of 120 to 140 hides about a bushel of lime is put 
 into the tub, and one or two pails of water poured on ; the 
 vessel is then to be covered with thick canvas. As the 
 
AMERICAN TANNING. 233 
 
 water is absorbed more is added if required, but our own 
 experience in the slaking of lime teaches us that a much 
 less quantity than two pails of water would be sufficient 
 to slaken a bushel of lime. It is always a great advantage 
 to cover up the vessel in which lime is slaked, since by so 
 doing much less water may be used, and the confined 
 steam aids the slaking greatly. 
 
 "Whereas in this country it is usual to put a considerable 
 quantity of lime in the pits, Mr. Schultz says, " Nothing 
 but pure limewater should ever be allowed to enter the vat. 
 This will not only render frequent ' cleaning out ' unne- 
 cessary, but will save the flesher's edge, and also save time 
 in many'respects." He allows three or four days only for 
 the liming, and in this time " the lime will not improperly 
 fill the hide, and when unhaired it may be speedily reduced 
 to a proper condition. The reduction (depilation) will be 
 well begun by throwing the hides or sides into a wheel 
 (drum), and with a flow of warm water turned on run them 
 for ten minutes. The advantage of warm instead of cold 
 water is very marked, and may at this stage of the process 
 be freely used with safety. It is always safe to use on 
 hides filled with lime heat to the extent of 110°. . . This 
 rinsing process will remove the greater portion of the 
 lime, and will ordinarily prepare the hides for the liquor." 
 Some tanners, however, to get rid of the lime more effec- 
 tually, use hens' dung or sour bran liquor. This latter 
 precaution, however, is not considered necessary for sole 
 leather, while for upper leather, it is necessary that the 
 skins should be as free as possible from lime before they 
 go into the handlers. The sour liquors of the handlers 
 are deemed sufficiently active to remove the lime from 
 heavy hides, provided the fibre has not been unduly 
 strained in the beam house. 
 
 Unhairing by Prof. Lupkin's Process. — By this method 
 one tanner in New Jersey prepared not less than 50,000 
 hides annually with great success. His packs were made 
 up of about 50 hides each, either cured, green, salted, or 
 dry Buenos Ayres or Hio Grande. The green weighed 
 about 50 lbs. and the dry about 20 lbs. For such a pack 
 
234 LEATHER MANUFACTURE. 
 
 80 lbs. of lime would be slaked, but the lime was not watered 
 after slaking, as usual, but was left in the condition of a 
 thick paste. A small portion of this was kneaded thoroughly 
 with 10 lbs. each of soda ash and powdered sulphur. When 
 these substances were well mixed, they were thrown into 
 the tub in which the bulk of the lime reposed, and while 
 this was still warm ; the whole were then thoroughly 
 mixed, and the tub then filled with lime liquor and the 
 whole well stirred. When this was done, the mixture was 
 poured into the vat, and the whole thoroughly plunged. 
 No more liquor was employed than would be sufficient to 
 cover the 100 hides when thrown in. The lime was kept 
 up to summer heat by the application of steam. The 
 handling was performed once or twice a day, if thrown 
 into the vat as usual. Mr. Schultz says, " There is no 
 doubt that it is a good method of unhairing for any 
 hides or skins, and when a soft and smooth grain is 
 desirable it is a valuable improvement. Of course, it 
 is slightly more expensive than pure lime, and, for this 
 reason, has not found general favour/' The soda ash in 
 this process combines with a portion of the lime, forming 
 caustic soda. 
 
 By another process the hides, after the usual preparation, 
 are thrown into a strong lime for 8 or 10 hours, when they 
 are taken o at and immersed in water up to 1 1 1°. The warm 
 water soaks, softens, and swells the roots of the hair, and 
 has much the effect of the " scalding " applied to hogs. 
 " So little lime permeates the inner fibre, that, after a slight 
 wheeling, the hides may be thrown into cold water and 
 allowed to cool and plump preparatory to taking their place 
 in the handlers. The process is strongly commended for 
 sole leather, particularly where great firmness of fibre is 
 desired. The tanner who tries this method must be satisfied 
 if he gets twenty to thirty sides per man, unhaired and 
 fully completed for the liquor, per day." Instead of the 
 usual handling in the lime, the hides may be " strung " 
 together, and reeled over from one pit to another by means 
 of the hand-reel, Fig. 43. This simple contrivance for 
 removing hides from one pit to another, as a substitute 
 
AMERICAN TANNING. 
 
 235 
 
 for the usual handling, should command attention. In 
 speaking of its capabilities Schultz says, "The facility 
 with which packs may be thus transferred from one pit 
 to another commends this skeleton reel to all tanners. It 
 is safe to estimate the performance of this machine with 
 two men as equal to that of six men by the old process. 
 Besides, it does not require either man to stoop to his 
 work, and the labour is therefore easier. The stand and 
 
 Fig. 43. 
 
 skeleton drum should be made of as light material as 
 possible, so that its transfer from one vat to another may 
 be effected by two men with ease. As there need be but 
 one of these reels in an ordinary sized tannery, the tanner 
 can well afford to have the frame, drum, and bearings 
 made of substantial but light materials, well adjusted in 
 all parts, even with brass bearings. Two men can shift 
 10,000 in ten hours. The hides may be tied together with 
 strings.'' 
 
 Beam Work — "No amount of labour andcare," says Mr. 
 Schultz, " in the after processes can atone for neglect in 
 this department. The flesh should all be removed, and the 
 
236 LEATHER MANUFACTURE. 
 
 natural structure of the hide (pelt) should not be disturbed 
 or even touched with the edge of the flesher.*. . . The 
 usual flesher and half-round beam are too familiar to the 
 tanner to require notice in this connection, but within a few 
 years the French and German beam-knife has been intro- 
 duced, and received with general favour. This knife is about 
 one-third larger than ours, and is not more than two inches 
 wide ; the material is the best steel, and is not more than 
 a quarter of an inch in thickness in the rib or centre. The 
 blade is so supple that the handles can almost be brought 
 together. It is claimed for this knife that by its supple 
 nature it bends around the rounded convex form of the 
 beam, and makes a flatter cut on the flesh of the side, less 
 concave than a stiff, straight-edged flesher cutting on an 
 oval or convex surface. To this extent the new knife cer- 
 tainly does present advantages, and may be safely trusted 
 to do good work in skilled hands." 
 
 Trimming or Rounding. — This author speaks highly 
 of the economy and judgment displayed by the English 
 tanners in their method of rounding, and gives the following 
 reasons why this method is adopted : — 1st. The shoulders 
 and offal are much thinner than the butts, and, therefore, 
 tan in a shorter time. 2nd. The offal being used where a 
 tough fibre is required, slack, or at most a full tanning, 
 is all that is required. 3rd. The boot and shoe manu- 
 facturers, not only of Europe but of America, have so 
 classified their work that those who use butt leather 
 largely do not require so much " inner soleing " and 
 "welting" as would come from the bellies and shoulders 
 of these out-soles. 
 
 Mr. Schultz says, " It is probably true that the population 
 of Great Britain is better and more economically shod than 
 any other people in the world. A portion of the economy 
 is due, however, to iron rather than leather, f Much of the 
 economy here conceded arises from their method of tritn- 
 
 * Fleshing-knifs. 
 
 t This remark is specially applicable to the present time, when metal 
 sole and heel "protectors" are so extensively applied by the public 
 themselves. 
 
AMERICAN TANNING. 237 
 
 ming and rounding their hides and skins. That which 
 belongs to the glue-maker never goes beyond the beam 
 house in any tannery in Europe." 
 
 Grinding the Bark — In the United States the spent 
 tan is largely used as fuel by the tanner for the generation 
 of steam for his grinding-mills, for the leaching of bark, 
 and other purposes, and to a great extent has supplanted 
 the use of all other fuel, and even water-power. " So 
 absolutely inexpensive is this substitute," says Mr. Schultz, 
 " that power and heat may be used without stint and limit 
 in the manipulations of all our modern sole leather 
 tanneries. . . . The fact, then, stands conceded that the 
 wet spent tan from an ordinary sole leather tannery will 
 give ample power to grind all the bark and heat all 
 the liquors required." He writes strongly against mills 
 which grind at high speed, and doubts whether a motion 
 over 80 revolutions per minute is either profitable or 
 effective. The benefits which may be derived by adopting 
 a higher speed in nowise overbalance the defects in 
 grinding and danger of fire from excessive friction. " A 
 quick motion has the effect to ' throw up ' and ' back ' the 
 bark, rather than take it in and pass it through the grind- 
 ing surfaces, as a slower motion will." He recommends 80 
 revolutions on a small and 70 revolutions on a large mill 
 as the proper motion. 
 
 Speaking of the American methods of grinding and 
 leaching, Schultz says it is estimated that from 7 to 10 
 per cent, of tannin is left in the bark, and it is doubtful 
 if any of their methods will take out the remainder profit- 
 ably. He says, moreover, that " the time may come when 
 hemlock and oak-bark (the chief materials used in the 
 States) will be so scarce and dear as to necessitate other 
 means than grinding and leaching for extracting all the 
 strength from the bark." It seems strange that when our 
 American cousins are so ingeniously utilising what they 
 consider their " waste " tan, that they are wasting* in a 
 true sense from 7 to 10 per cent, of material. 
 
 * Chemists are now employed in all large American tanneries, and all 
 mateiials much more thoroughly extracted under their direction. — Ed. 
 Fifth Edition. 
 
238 LEATHER MANUFACTURE. 
 
 Leaching. — " The full and perfect extraction of all the 
 tannin from the bark is not only desirable, but it is of 
 primary importance ; it is equally essential, however, that 
 this subtle elixir should be extracted without deterioration 
 or injury. It is found in practice not at all difficult to 
 wash out all the extractive or soluble matter from the 
 bark ; but to separate and take out the greatest amount of 
 tannin, leaving the largest portion of colouring and 
 resinous matter behind, is quite a different matter, and 
 one which has taxed the efforts of our best tanners. The 
 system of leaching which will enable the tanner to control 
 and separate these qualities is, in my judgment, the 
 system to be most commended." In this view Mr. Schultz 
 does not appear to be supported by some of the largest 
 American tanners, as he frankly admits, but he believes 
 that their theory is based on the assumption that colouring 
 matter, entering into the substance of the hide, gives 
 weight ; and that also the resinous matter in some myste- 
 rious way attaches itself to the leather, defying the action 
 of the scrubber to wash it off. To this theory he strongly 
 objects, and asserts that " tannin, and not colouring or 
 resinous matter, enters the fibre and gives weight." But if 
 Davy's well-known theory be accepted, does not the colour- 
 ing matter (setting aside the resinous matter) enter into the 
 substance of the hide with the vegetable extractive, which 
 forms an essential ingredient in the formation of leather ? 
 
 The system of leaching in America, by the application 
 of heat, appears to be open to objectioD, since the chief 
 tanning agent, hemlock-bark, yields not only an objection- 
 able colour, which is more freely extracted in hot than in 
 cooler liquors, but also resinous matter, which can play no 
 useful part in tanning. " The union-crop leather tanners," 
 Mr. Schultz remarks, " have learned to appreciate the value 
 of moderate instead of extreme heat, and when better 
 methods of grinding and screening the bark shall be appre- 
 ciated at their full value, then I assume that even less heat 
 than at present will be employed by them, and the more 
 nearly summer-heat (60°*) is adhered to, in the head leach, 
 * The summer-heat in this country is 78° Fahr. 
 
AMERICAN TANNING. 239 
 
 the more modified and controllable will be tbe colour." 
 Since it is so well known that tannin is freely soluble in 
 cold water, and that colouring matter is more readily 
 extracted from bark by hot than by cold water, it must 
 certainly be erroneous, especially if the colouring matter 
 is of an objectionable character, to use heat for the leaching 
 of this otherwise most useful bark, hemlock. Mr. James 
 Cleaver, an American tanner of repute, proved that he could 
 make from 190 to 200 lbs. of leather with one ton of bark, 
 never employing a higher temperature for his head leach 
 than that of summer-heat, except in winter. 
 
 Of the several systems of leaching adopted in America, 
 we may select the following : — 
 
 The " Press " Leach. — The number of leaches in a set 
 (or round) should correspond with the number of days in 
 the week. By this method one new leach is filled in each 
 round every day in the week, but if more than one leach 
 is required for the day's work, then the sets of leaches 
 should be multiplied rather than disturb the order of the 
 round. This arrangement gives at least five days for the 
 leaching of all the bark, which is fully time enough. It 
 is strongly recommended not to break the round, which 
 only leads to confusion and waste. As to when and where 
 heat may be applied, Schultz says, " Under no circum- 
 stances is heat to be applied to any other than the back or 
 weakest leach. This will bring the strong liquor of the 
 set on the head leach comparatively cold, or at most 
 summer-heat. This course will take all the liquors in the 
 yard in a proper condition to go upon the leather without 
 coolers or waiting. It will leave behind much of the 
 colouring and resinous matter, and send forward a pure 
 tan liquor free from all sediment and impurities." 
 
 The principle on which the "press leach " works is thus 
 described: "Warm water or liquor is more expanded, 
 and consequently lighter than cold. Strong liquor is 
 heavier than weak. Now if we put the two light condi- 
 tions together, viz., hot and weak, and place them on top 
 of the heavy and cold liquor, they will remain separate 
 for all the time, or so long as these conditions are main- 
 
240 LEATHER MANUFACTURE. 
 
 tained. A simple experiment with water and tan liquor 
 in a tumbler will demonstrate this practical result. Weak 
 tan liquor will stand all day on the top of strong and 
 heavy liquor, if not agitated. Now if to the weak liquor 
 we add heat, the separation will be still more marked. A 
 tumbler half filled with weak and warm liquor may be 
 forced out of the top by gently inserting strong and cold 
 liquor underneath by means of a pipe. The action of 
 these bodies, if the experiment is carefully made, will 
 satisfy any one that the system of press leaching can be 
 carried on without mixing the liquors on their passage, if 
 the system recommended be followed." In other words, 
 it is a question of gravity ; the heavier liquid, or that 
 which is richest in tannin, will form the lower stratum, 
 and the weak the upper stratum ; and if strong cold 
 liquor were introduced from above, through a funnel con- 
 nected to a long tube, the end of which reached to the 
 bottom of the vat, the weaker liquor would gradually rise 
 to the surface. 
 
 In working the press leaches, each of the six leaches 
 is filled at all times from two-thirds to three-fourths 
 with bark, and stands covered with liquor varying in 
 strength with the strength of bark in each. " Let us sup- 
 pose," says Schultz, "that the head leach has just been filled 
 with fresh- ground tan ; the last or back leach is filled with 
 spent tan ready to pitch, and the intermediate four leaches 
 are divided into both, as to strength of liquor and age of 
 bark, from these two points. No liquor is sent into the 
 yard except from the top of the head leach, and where 
 very strong liquors are needed, only one liquor is so sent 
 from each head leach, so that the accumulated strength of 
 all the bark in one leach is concentrated in this one liquor. 
 If a less degree of strength is required, then two runs 
 may be taken off, and in exceptional cases, even three or 
 four. The liquor thus sent into the yard is not returned 
 until the strength is taken from it, and it is either sent off 
 into the stream as worthless, or sent back to the back 
 leach, after passing through the heater, and heated up to 
 100° or 120°. I shall insist that the spent tan liquor, 
 
AMERICAN TANNING. 241 
 
 which is accumulated acid (gallic), shall go back for sole 
 leather, and shall go off into the stream if light leather, 
 such as calf, kip, or even harness, is to be tanned." 
 
 The usual practice in working the leaches is to run the 
 strongest and newest liquor direct from the leaches upon 
 the head packs on the last layer. These liquors should 
 stand at fully 30° by barkometer. After thirty days' use 
 they will be reduced to 24°, a portion of which indicated 
 strength will be " acid." Twenty days' further use on the 
 third layer will reduce the strength to 18°, and so on until 
 the liquors will be nearly exhausted and contain little else 
 than acid.. These liquors are put on the first layers, or 
 run into the handlers to be more fully exhausted. The 
 liquors are run from the leaches by covered and enclosed 
 wooden tubes or bored- out logs. Mr. Schultz speaks 
 strongly against the practice, even if accidental, of allowing 
 warm liquors to come in contact with half- tanned or green 
 hides which have been sweated, especially in warm 
 weather, as decomposition and injury are sure to result. 
 
 Raising with Vitriol — The practice of the American 
 tanners with regard to the employment of sulphuric acid 
 (oil of vitriol) for raising the pelt is variable. While 
 some pass the sides through the handlers before introducing 
 them into the acid liquor, others use the acid first and 
 colour them afterwards ; other tanners, again, add the acid 
 to their handler liquors, by which they plump and colour 
 the pelts at the same time, and when this method is 
 adopted the strength of the liquor is renewed with sweet 
 highly coloured liquor as each new pack is treated. 
 Regarding the employment of sulphuric acid for this 
 purpose, Mr. Schultz observes, " Yitriol- raised leather, 
 when treated in the after process in weak liquors, produces 
 a most unsatisfactory result. The grain is poor, the fibre 
 coarse and ' hatty.' I do not here attempt to solve the 
 mooted question whether vitriol does not destroy the 
 tannin. It is conceded that it will plump and hold the 
 fibre and will facilitate the tanning, but whether these 
 advantages in an economical point of view are not more 
 than counterbalanced by its destructive action on both 
 
242 LEATHER MANUFACTURE. 
 
 fibre and the tannin I shall leave for future experience to 
 determine." He, however, concedes that vitriol "pre- 
 serves the hides, and holds, when combined with salt, the 
 gelatine from decay," and he moreover states that "all the 
 green sheepskins that come from England to this country 
 (America) in casks are preserved by this process, and may 
 be so held without damage for years ; " but he further 
 observes that unless the acid in these skins is neutralised 
 before they are put into tan liquor, they swell to more 
 than double their wonted thickness, and will tear as easily 
 as brown paper. 
 
 While Mr. Schultz allows that sulphuric acid raising 
 may be adopted, without material damage, for hides which 
 have been limed, he says, " In my judgment vitriol should 
 never be used to raise purely sweat stock," in which, 
 we imagine, none will differ from him ; while it is equally 
 clear that lime would be an appropriate steep for sweated 
 stock. 
 
 Handling. — In America the system of handling by 
 withdrawing the packs and allowing them to drain and 
 then returning them to the handlers, as is usually practised 
 in this country, or of working the handlers in rounds, have 
 been substituted by mechanical appliances which reduce 
 the labour of the workmen in this branch of the business 
 to a minimum. The most generally adopted contrivances 
 are the hand-reel (Fig. 43) and the " rocker." The former 
 machine is placed in the alley- way between the pits to 
 be shifted, and the hides to be transferred being tied 
 together, are forced over from one pit to another by means 
 of the revolving drum, which is turned by its handle by 
 one man, while a second man adjusts the hides in the 
 "head" pit. It takes only four minutes for two men to 
 transfer 150 hides from one pit to another. 
 
 The Rocker Handler is a frame set in the top of pits, 
 and is made of wood. The frame fills the pit within two 
 inches of each end and one inch on each side, so that 
 when it rocks from the centre it will play without 
 touching (Fig. 44). It should be made of two-inch timber, 
 and framed two by sis inches. The end-pieces should be 
 
AMERICAN TANNING. 
 
 243 
 
 made of hard wood not liable to split, since these have to 
 bear the strain of the whole pack. The centre of this 
 frame rests on pivots, supported by uprights from the 
 bottom of the pits. A stop at each end of the pit prevents 
 the rocker from dipping more than about eight inches. 
 The hides are attached alternately by the head and tail to the 
 end-pieces, with backs up and bellies down, by means of 
 hard wooden pins permanently fastened in the head frame- 
 pieces. Usually one end is fastened directly to or over 
 the pin, and the other by an adjustable string which 
 need not be more than a foot long, and may be made by 
 a permanent slip knot to act continuously. 
 
 Sometimes " white spots " appear upon the surfaces of 
 sweated hides after having been partially coloured in the 
 handlers. These spots have been proved to be due to 
 grease left by imperfect beam work, and the most approved 
 remedy for this is caustic soda, a solution of which is 
 rubbed over the spots, when they quickly disappear. 
 This defect does not apply, of course, to limed goods. 
 
 _ The Layers. — Eespecting the proper disposition of the 
 hides in these pits, Schultz observes, " The question has 
 often been raised whether the hides should be laid grain 
 or flesh side up in the layers. The practice is to lay 
 grain up, and this is justified on the ground that in 
 
244 LEATHER MANUFACTURE. 
 
 ' hooking up ' the grain is more apt to be scratched and 
 marked than if laid flesh side up. If, as it seems quite 
 likely, colour is seriously affected (particularly hemlock 
 tannings), by the settling of the colouring matter on the 
 grain, and a deeper, darker red is the result, then I think 
 tanners may well inquire whether, in their attempts to 
 avoid hook-marks, they do not entail upon their stock a 
 worse evil. Besides, I will suggest in this connection 
 whether it is not probable that tannin will enter the fibre 
 of the hide more naturally from the flesh than from the 
 grain surface. The pores of the hide, when on the 
 animal, certainly do open their valves outwardly from the 
 flesh, for all the emanations of the animal body go 
 through these outward- opening valves or pores of the 
 skin, and never receive back from the grain to the flesh." 
 To this we may add, as a further suggestion, that while 
 the tannin of the bark and ooze is being gradually 
 absorbed by the hides, the liquor is kept in a continual 
 state of imperceptible movement, by which the tendency 
 of the exhausted liquid would always be upivard ; while 
 the liquid renewed with tannin from the ground bark, 
 being now heavier, would take its place, and thus a con- 
 tinual upward movement would result, as in the circulation 
 of sap in a tree, though not of course with the same vigour. 
 
CHAPTER XIX. 
 
 HEMLOCK TANNING. 
 
 Pratt's System of Tanning. — Hemlock Tanning of New Lebanon. — 
 Hibberd's Process. 
 
 The great success which attended the employment of 
 hemlock-bark in some parts of the United States induced 
 English tanners to turn their attention to this prolific 
 source of tanning material, and during the past thirty 
 years or so a a extract of the bark has been imported from 
 Canada in large and increasing quantities. The hemlock 
 spruce-fir abounds in the northern states of Pennsylvania 
 and Canada, and the readiness and cheapness with which 
 the bark is obtained have rendered it the chief tanning 
 material of those states, and a source of considerable in- 
 dustry in Canada. The extract comes over to this country 
 in casks, of the consistence of treacle, and is of a dark 
 brown colour. This extract is not soluble in cold water, 
 owing to the large amount of resinous matter it contains, 
 but it is freely dissolved in water at 150° Fahr. It may 
 be employed alone, but owing to the indifferent colour it 
 imparts to leather, it is generally used in combination 
 with other tanning materials. According to Ramspacher, 
 it yields 25 per cent, of tannin. 
 
 Pratt's System of Tanning.— The Hon. Zadock Pratt, 
 who was one of the most skilful and experienced manu- 
 facturers of leather in the United States, furnished Dr. 
 Morfit with some very elaborate and interesting particulars 
 concerning his system of working, during a long series 
 of years, at his famous tanneries at Prattsville, N.Y., 
 from which we make the following interesting: extracts : — 
 
246 LEATHER MANUFACTURE. 
 
 " Since I first commenced business, the gain in weight, 
 in converting hides into leather, has been increased nearly 
 50 per cent. That is, from a quarter to a third more 
 leather can now be obtained from a given quantity of 
 hides than at the time when I learnt my trade at my 
 father's tannery, conducted in the old-fashioned way. 
 The great improvement in weight seems to have been 
 gained by the judicious use of strong liquors or ' ooze,' 
 obtained from finery- ground bark, and by skilful tanning. 
 The loss and wastage upon hides, from hair, flesh, &c, 
 may be estimated at from 12 to 15 per cent. In order to 
 produce heavy weights, the hides should not be reduced 
 too low in the beam house, and should be tanned quickly 
 with good strong liquors, particularly in the latter stage of 
 the operation. To green hides particularly, nothing can 
 be more injurious than to suffer them to remain too long 
 in weak ooze. They become too much reduced, grow soft, 
 flat, and flabby, lose a portion of their gelatine, and refuse 
 to ' plump up.' On the other hand, the effects of an early 
 application of ooze that is too strong and too warm to 
 green hides is very injurious. It contracts the surface 
 and fibres of the skin, tanning at once the exterior layers 
 so ' dead,' as it is termed, as to shut up the pores and 
 prevent the tannin from penetrating the interior. This 
 renders the leather harsh and brittle. It will be seen 
 from this that, in the question of the proper strength of 
 liquor alone, there is room for the exercise of the greatest 
 judgment and the most extensive experience. In the 
 impossibility of adapting fixed rules to the innumerable 
 variety of cases, nothing can be depended upon but the 
 judgment of the practical tanner. 
 
 " In softening hides and preparing them for the process 
 of tanning, a great deal depends upon the judgment of 
 the person superintending the operation, inasmuch as the 
 diversities in the qualities and characteristics of the hides 
 render it impossible to subject them to any more than a 
 general mode of treatment. In ' sweating,' the character 
 of the hides and the temperature are essential but ever- 
 varying considerations. As a general rule, however, the 
 
HEMLOCK TANNING. 247 
 
 milder the process of preparing the hides for the bark 
 the better. Unnecessarily severe or prolonged treatment 
 is inevitably attended with loss of gelatine, and a conse- 
 quent loss of weight and strength in the leather. Too 
 high a temperature is particularly to be avoided. In 
 almost every lot of hides, particularly Orinocos, however, 
 there are generally some that prove very intractable, 
 resisting all the ordinary modes of softening. For such, 
 a solution of ashes, potash, or even common salt, will be 
 found to be beneficial, and peculiarly so in hot weather. 
 As I have said, no precise rule can be given as to the 
 length o£ time required for the preliminary processes of 
 soaking and ' sweating,' so much depending upon the 
 qualities of the hides and the temperature at which these 
 operations are conducted. 
 
 " The following table may, however, be found useful in 
 conveying an approximation to a definite idea of the 
 practice in my tannery : — 
 
 Soaking — 
 
 Temperature: 40° 50° 60° 70° 
 
 Days. Days. Days. Days. 
 
 Buenos Ayres hides 10 to 12 8 to 12 6 to 8 3 to 6 
 
 Carthagena and Laguaira . . 8 „ 12 7 „ 9 5 „ 7 2 „ 3 
 
 Sweating — 
 
 Buenos Ayres hides 15 „ 20 12 „ 16 8 „ 12 2 „ 3 
 
 Carthagena and Laguaira ..15 „ 20 10 „ 15 6 „ 8 2 „ 3 
 
 " I would here remark that I changed the process of 
 liming to sweating in 1836 — the only change in tanning 
 I have made in twenty years ; and for heavy sole leather 
 it has been proved to be quite as good as liming, if not 
 better, and somewhat cheaper, besides yielding a greater 
 gain in weight, and, when well tanned, making leather 
 more impervious to water. Liming and bating, however, 
 for upper and light leather, is preferable, and if the same 
 improvements had been adopted with the lime process of 
 strong liquid and quick tanning, it is not yet certain 
 that the same results would not have been attained. 
 
 " Salted hides do not require more than two-thirds the 
 time to soak, but generally longer to sweat. After the 
 
*4* LEATHER MANUFACTURE. 
 
 hides are prepared for tanning, the next process is what 
 is commonly called ' handling,' which should be performed 
 two or three times a day, in a weak ooze, until the grain 
 is coloured. New liquors, or a mixture of new and old, 
 are preferable for Spanish or dry hides, old liquors for 
 slaughters. They are then, after a fortnight, laid away 
 in bark, and changed once in two or four weeks, until 
 tanned. Much care and judgment are necessary in pro- 
 portioning the continually increasing strength of the 
 liquors to the requirements of the leather in the different 
 stages of the process. The liquors should also be kept as 
 cool as possible, within certain limits, but ought never to 
 exceed a temperature of 80° ; in fact, a much lower tem- 
 perature is the maximum point if the liquor is very 
 strong, too high a heat, with a liquor too strongly charged 
 with the tanning principle, being invariably injurious to 
 the life and colour of the leather. From this it would 
 seem that time is an essential element in the process of 
 tanning, and that we cannot make up for the want of it 
 by increasing the strength of liquor or raising the tem- 
 perature at which the process is conducted, any more than 
 we can fatten an ox or a horse by giving him more than 
 he can eat. 
 
 "I have mentioned the injurious effects resulting from 
 too strong a solution of the active principle of the bark ; 
 on the other hand, the use of too weak solutions is to be 
 avoided. Hides that are treated with liquor below the 
 proper strength become relaxed in their texture, and lose 
 a portion of their gelatine ; the leather necessarily loses 
 in weight and compactness, and is much more porous and 
 pervious to water. The warmer these weak solutions are 
 applied the greater is the loss of gelatine. To ascertain 
 whether a portion of weak liquor contains any gelatine in 
 solution, it is only necessary to strain a little of it into a 
 glass, and then add a small quantity of a stronger liquor. 
 The excess of tannin in the strong, seizing upon the dis- 
 solved gelatine in the w T eak liquor, will combine with it and 
 be precipitated in flakes of a dark curdled appearance to the 
 bottom. At the Prattsville tannery the greatest strength 
 
HEMLOCK TANNING. 249 
 
 of liquor used for handling, as indicated by Pike's barko- 
 meter, is 16° ; of that employed for laying away, the 
 greatest strength varies from 30° to 45°. 
 
 "After the leather has been thoroughly tanned and 
 rinsed or scrubbed by a brush, machine, or broom, it will 
 tend very much to improve its colour and pliability to 
 stack it up in piles and allow it to sweat until it becomes 
 a little slippery from a kind of mucus that collects upon 
 its surface. A little oil added at this stage of the process, 
 or just before rolling, is found to be very useful. Great 
 caution is necessary in the admission of air in drying when 
 first hung up to dry. No more air than is sufficient to 
 keep the sides from moulding should be allowed. Too 
 much air — or, in other words, if dried too rapidly in a 
 current of air — will injure the colour, giving a darker hue, 
 and rendering the leather harsh and brittle. To insure 
 that the thick parts, or butts, shall roll smooth and even 
 with the rest of the piece, it is necessary that the leather 
 should be partially dried before wetting down for rolling, 
 and that when wet down it should lay long enough for 
 every side to become equally damp throughout." 
 
 The average time for tanning by hemlock, in America, 
 amounts to five months twenty-seven days ; sole leather, 
 however, occupies from four to six months, according to 
 the strength of the liquor used and number of sides in the 
 vats, and, according to Pratt, the quicker the tanning is 
 effected the better is the result. 
 
 Hemlock Tanning of New Lebanon, M\J. — Dussauce 
 gives the following description of the process of tanning 
 with hemlock at the Shaker tannery of New Lebanon, as 
 furnished to him by the Shaker tanner, Mr. Fred. Sizer. 
 " I take a pack of calf skins — say 100 dry skins — and put 
 them in a water vat to soak ; after they have soaked two 
 or three days I take them out and mill them (a wheel is 
 best for milling hides) ; I then beam them on the flesh 
 side, removing all the lean meat and grease from the 
 skins, stretching them out well with the beaming-knife, 
 and put these into a vat of clean water until they are soft 
 enough to go into the lime. They must be as soft as 
 
250 LEATHER MANUFACTURE. 
 
 when they came from the animal, or as near that as you 
 can get them. If the hides are not soft before going into 
 the lime, they never can be, and the leather will always 
 be hard. 
 
 "Fresh hides, that come direct from the butchers, are 
 put in water a day or two ; change the water once, beam 
 them on the flesh side ; they are then ready for the lime. 
 I make my lime in a vat 8 feet long by 4 wide and 4 deep. 
 One bushel of lime and 2 gallons of soft soap put in the vat 
 two-thirds full of water will make a lime sufficient for 
 100 calf skins or five sides of upper leather. The hides 
 should be handled out every other day, while in the lime, 
 to air and change their position ; then stir the lime well 
 before they are put back. The lime needs strengthening 
 every time a new pack is put in by adding, say half-a- 
 bushel of lime and two or three quarts of soap. I lime 
 my calf skins and upper leather hides until the hair comes 
 off easily, but sole leather hides should be limed as little 
 as possible to get the hair off ; then unhair them, wash 
 them out in the mill, beam them on the flesh side, trim 
 off the pates and shanks, and put them in the bate. 
 
 " I put five or six bushels of hens' dung into a vat of the 
 same dimensions as used for the lime and till two-thirds full 
 of water and let it stand two or three days to ferment. I let 
 my skins remain in the bate two or three days in warm 
 weather and longer in cold ; haul them two or three times 
 while in the bate, and work them twice on the grain with 
 a common worker on the tanner's beam ; mill them before 
 working the last time, then beam them, and they are 
 ready for the tan-vats. I make a liquor of moderate 
 strength to handle them in, put them in this liquor, and 
 stir them with a pole a while, then handle them up smooth 
 on a box or rack three or four times in the course of the 
 day; let them remain in this until the next morning, then 
 change the liquor, giving them about the same strength 
 as at first ; handle them two or three times a day in the 
 liquor, and when this is exhausted change again, and 
 handle less as the skins get coloured and the grain set. 
 " I make my liquors of hemlock-bark, ground and put 
 
HEMLOCK TANNING. 251 
 
 in leaches, and pump in the exhausted liquor. The first 
 strength of my leaches I draw off the sole leather vats. I 
 draw off the leaches two or three times before taking it 
 from my upper leather and calf skins, and these I keep in 
 mild, sweet liquors through the whole tanning process. I 
 handle my hides and calf skins through until tanned, 
 changing the Kquors as they get exhausted. After they 
 get well along I handle them three times a week. They 
 will do to lay longer, but will tan faster if handled often. 
 When my calf skins have been in the tan two or three 
 weeks I shave clown the necks, and after my upper 
 leather, has been in four or five weeks I shave it down to 
 a proper thickness. 
 
 " In my experience in tanning, which has extended 
 through forty-two years, I have used both hemlock and 
 oak bark, and I find that mild sweet liquors are far best 
 for tanning all kinds of upper leather. The hide in the 
 raw state is tougher than when tanned, and that toughness 
 ought to be preserved as much as possible, to make good 
 pliable leather, and the slow process of tanning with mild 
 liquors will do it. Strong liquors have a tendency to 
 make the leather hard and liable to crack. The hides for 
 upper leather should not be tanned any more than 
 thoroughly through; if tanned longer than this it has 
 the same effect upon them as strong liquor ; but the 
 longer sole leather is tanned the better. When I think 
 my leather is nearly struck through I try it by cutting 
 into the thickest edge, and when tanned through take it 
 up and scour it out on the wheel to cleanse it from the tan 
 and soften the grain ; then take them to the currying 
 shop, and the calf skins I skive, and uppers smooth down 
 with the currying knife ; then put them in a tub of water 
 and scour them on the table with a brush, stone, and 
 slicker ; dry them a little, temper them, and then put 
 them on the table and set them on the grain side to work 
 the grain out smooth. After that apply some thin stuff- 
 ing made of oil and tallow, then turn them over, flesh side 
 up, and set them out with an iron slicker ; then apply the 
 stuffing more plentifully, made thicker with more tallcw ; 
 
252 LEATHER MANUFACTURE. 
 
 then hang them on sticks and dry them, and then pack 
 them down in a pile, and let them stay two weeks. I 
 then take them and rub off what stuffing does not strike 
 in, and whiten them with a currying knife or slicker. 
 I commonly whiten my calf skin and kips with a slicker, 
 and finish in the French style. Since the French degras 
 has come into use, I have used it for calf skins and kips. 
 I have also for some time used tansy in my liquors. 
 There is an acid in tan that injures the leather which 
 tansy neutralises and keeps the liquor sweet." 
 Hibberd's Process. — This process consists — 
 First, in the use of a compound of lime, wood ashes, 
 or potash, and salt for removing the hair or wool, and 
 also for the purpose of so-called " liming," instead of 
 using the lime alone. Lime and ashes have been used 
 separately for the purpose of removing the hair, wool, 
 &c, but lime alone requires several days, and in cold 
 weather weeks, to effect these objects, by which, the 
 inventor says, the skin is more or less injured. " On 
 the other hand, ashes alone act too rapidly, and would 
 destroy the skins altogether. When lime, ashes, and 
 salt are combined in proper proportions, the salt modifies 
 the action of the alkalies, and protects the skin from 
 their caustic properties, so that the process of unhairing 
 and liming are both rendered more expeditious and safe 
 than by the old method, while the texture of the skin is 
 uninjured, and consequently the leather is much stronger." 
 Second, in the use of a composition of salt, sulphuric 
 acid and sumac, oak, hemlock-bark, or other tanning 
 material for the process of tanning. The salt, sulphuric 
 acid and tannin being mixed together in water in certain 
 proportions hereafter mentioned, a portion of the salt is 
 decomposed by the acid, forming sulphate of soda, and 
 setting free muriatic acid, which acid, being absorbed by 
 the water, acts directly and rapidly on the skins, opening 
 their pores, and preparing them for the tannin, which, 
 being present also in the mixture, immediately and readily 
 unites with the gelatine of the skin, forming leather more 
 expeditiously and perfectly than by the usual methods. 
 
HEMLOCK TANNING. 253 
 
 Preparation of the Skins. — By this process the skins 
 may be prepared as usual, but the inventor prefers to 
 employ the following-, which he calls composition No. 1 : — 
 
 Quicklime, fresh slaked J bushel. 
 
 Wood ashes J ,, 
 
 Common salt 3 pints. 
 
 For the ashes may be substituted from 3 lbs. to 5 lbs. 
 of potash. 
 
 To remove the hair or wool, the above composition is to 
 be mixed with sufficient water to make a thick paste, and 
 applied to the flesh side of the hides in the usual way, the 
 skins to be folded and kepfc at a temperature of summer- 
 heat. In a few hours they will be ready to pull. For 
 " liming " or " ashing," he uses the same composition, 
 No. 1, mixed with a sufficient quantity of water in a vat 
 to immerse the number of skins required to be treated. 
 One bushel of the mixture is equivalent to one bushel of 
 lime alone. The liming and ashing process may be con- 
 ducted at a temperature of 40° to 60° Fahr. 
 
 Composition for Tanning. — For six dozen full-sized sheep, 
 deer, goat, or similar skins of the same size : — 
 
 Common salt 18 lbs. 
 
 Sulphuric acid 2 ,, 
 
 Sicily sumac, or quercitron bark 36 „ 
 
 Muriatic acid 2 ounces. 
 
 Dried clover , . . . . 18 lbs. 
 
 Soft water 150 gallons. 
 
 The sumac or dyestuffs are first exhausted with water, 
 and then the salt is added to the liquor, apportioned so as 
 to ensure perfect solution. The acids are afterwards added, 
 and the mixture thoroughly incorporated by stirring. 
 
CIIAPTER XX 
 
 TANNING BY ELECTRICITY. 
 
 Ward's Process. — Gaulard's Process. — G-aulard's Second Process.— 
 Meriten's Process. — Crosse's Process. 
 
 Tanning by Electricity.— Considering the many pur- 
 poses to which the electric current has been applied, and 
 the growing belief that this remarkable force is yet sus- 
 ceptible of many applications in the arts, it is not to be 
 wondered at that endeavours should be made to utilise 
 the current in the process of tanning. Whether success 
 will attend the employment of electricity in the tannery 
 has yet to be determined, and this, of course, can only be 
 done by careful and unprej udiced trial. The time has come, 
 we hope, when manufacturers cease to ignore new modes 
 of procedure merely on the ground that they are novel. 
 
 Ward's Process. — The inventor states that the object 
 of his invention is " the tanning of hides and skins by a 
 more speedy and efficient process than heretofore, in suit- 
 ably arranged vats or tanks, by the aid of electricity," 
 and it is effected in the following manner : he employs 
 the ordinary vats or tanks, which are lined with india- 
 rubber cloth, or other non-conducting substance. The 
 vats are filled with tan liquor, and the hides suspended 
 therein. The electric current is obtained by means of a 
 suitable battery. The effect of this, he states, is that the 
 current passes through the whole contents of the vats, 
 and the tanning process instantly commences, and con- 
 tinues until the strength of the liquor is absorbed, when, 
 if desired, fresh liquor may be added, and the current 
 again applied. By this means, the inventor states, hides 
 
 X 
 
TANNING BY ELECTRICITY. 
 
 255 
 
 and skins "may be fully and effectually tanned in the 
 space of a few hours." 
 
 Gaulard's Process. — The inventor says, " Various ob- 
 servations on the tanning of skins having demonstrated 
 that the reaction produced has been the decomposition of 
 the watery juice by the tannin, which seizes the oxygen, 
 whilst the hydrogen acts on the nitrogenous matter and 
 destroys it in changing it into ammoniacal salts, I have 
 concluded that for causing a rapid tanning it suffices to 
 
 Pig. 45. 
 
 oxidise the tannin and destroy the nitrogenous matter by 
 causing to intervene an electric current into the juice, 
 which decomposes the water of the liquor into oxygen and 
 hydrogen, and determines at the same time with rapidity 
 the reaction above mentioned." 
 
 In carrying out the process the hides or skins are dis- 
 posed as shown in the accompanying drawing. Fig. 45 
 is a tub a ; on the upper floor b of the double bottom b b 1 , 
 the hides are stratified in the usual way, that is to say, 
 with alternate layers of the hides or skins and tannin. In 
 the space between the two floors of the double bottom b b 1 
 
256 
 
 LEATHER MANUFACTURE. 
 
 are placed two parallel charcoal blocks C c, fixed by the 
 aid of copper clamps d d. The two charcoal blocks c 
 are put into communication by means of the wires a and 6 
 with the two poles of any electric generator, whereupon 
 the decomposition of the watery juice into its two elements, 
 oxygen and hydrogon, takes place, and the rapid assimila- 
 tion of the tannin and the hides or skins is effected. 
 
 Gaulard's Second Process. — Referring to the former 
 patent by the same inventor, the patentee says, " Instead 
 of placing both poles [of the electric generator] in the 
 
 Fisr. 46. 
 
 middle of the vessel, and thus causing the two gases 
 evolved by the decomposition of the water [oxygen and 
 hydrogen] to act simultaneously, one only of the elec- 
 trodes is placed in the centre of the vessel, the other 
 being arranged in a parallel plane, but in a corner, and in 
 the centre of a passage or conduit, arranged as illustrated 
 (see Fig. 46) in the drawing, that is to say, extending to 
 about four inches from the bottom of the vessel. The vessel 
 is filled with weak liquor, and the hides are suspended 
 therein from wooden crossbars resting on the sides of the 
 vessel. The electric current is then caused to pass in such 
 a manner that the negative pole is in the centre of the 
 vessel and the positive pole is in the ' conduit.-' Under 
 
TANNING BY ELECTRICITY. 
 
 257 
 
 these conditions the hydrogen alone acts upon the leather, 
 and causes the rapid destruction of the nitrogenous 
 matter contained therein. After undergoing this treat- 
 ment for eight daj r s, the liquor is changed for a stronger 
 tanning solution. The current is then reversed, so that 
 the pole in the middle of the vessel becomes the positive 
 pole and the pole in the conduit the negative. The 
 oxygen alone then acts upon the liquid, inducing a rapid 
 oxidation of the tannin, and its precipitation in this con- 
 dition in the cells formed by the gelatine and fibrine of 
 
 Fig. 47. 
 
 the hide. The hydrogen escapes into the air through the 
 conduit. Under these conditions the tannin is effected in 
 about fifteen days, and, in order to make the leather more 
 weighty, a stronger liquor must be employed, or the hides 
 may be stratified with layers of tan, as in the ordinary 
 method, at the same time keeping up the electrical action. 
 A wooden grating, arranged at a height of about eight 
 inches from the bottom of the vessel, is employed to keep 
 the electrodes from direct contact with the leather, as 
 shown in the engraving, Fig. 47." 
 
 Meriten's Process. — The bottom of the tan-pit is 
 composed of a block or slab of conducting carbon or char- 
 
 s 
 
258 LEATHER MANUFACTURE. 
 
 coal, or of two or more such blocks or slabs, covered with 
 a layer of the same substance in a coarse powder. A 
 copper wire coated with gutta-percha or other insulating 
 material is employed, one end of which is connected to the 
 carbon, and the other end, being carried up the side of 
 the pit to the exterior, is connected to the positive pole 
 of a battery. Upon the bottom so constructed, there is 
 placed a layer of bark or other tanning material, suf- 
 ficiently impregnated with water, and above this a hide or 
 skin, then another layer of bark or other tanning material, 
 then another hide, and so on in alternate succession to 
 any required number. A sheet or plate of zinc, in con- 
 nection with the negative pole of the battery, is disposed 
 at the upper part of the pit, and rests upon a layer of the 
 tanning material, and above the zinc there is placed a 
 final layer of tanning material sufficiently impregnated 
 with liquid as before. " On establishing an electric cur- 
 rent, a motion takes place between the two poles through 
 the hides or skins, the basic elements proceeding to the 
 negative pole and the acid elements to the positive pole, 
 whereby a molecular motion is produced and maintained 
 throughout the hides or skins, and the fixing of tannin in 
 their pores is effected. It is preferred to divide each of 
 the poles into two or more surfaces, according to the 
 depth of the pits and the quantity of hides which they 
 contain ; but it is in all cases essential that the anode 
 {positive pole) should be composed of an insoluble ma- 
 terial." This of course means carbon, or some metal not 
 acted upon by the tanning liquor when decomposed by 
 the current. • 
 
 Crosse's Process — This process has for its object First, 
 the unhairing of hides and skins, by the employment of 
 sulphide of lime, in which the hides are soaked, when the 
 hair becomes loosened and may be removed in the usual 
 way. Second, in producing electric effects on the matters 
 in the tan-pit. On one side of the pit is placed a plate 
 of lead, and on the other a plate of zinc, the plates cover- 
 ing the sides of the pit. The two plates are connected at 
 the upper parts above the liquid by a band of either 
 
TANNING BY ELECTRICITY. 259 
 
 metal. The skins are suspended in the pit, filled with 
 water, and remain three or four days. The water is then 
 removed or converted into ooze or tanning liquor, by- 
 adding bark or other suitable matter, or the water is 
 replaced by tanning liquor of a strength equal to about 
 15° of a saccharometer, and the liquor is kept up at that 
 strength for a week. The strength may be then increased 
 to 5° a week till it reaches 45°. The process may be 
 varied, and the strength and progressive increase of 
 strength in the tanning liquor modified. 
 
CHAPTER XXI. 
 
 CHEMICAL TANNING. 
 
 Knapp's Processes. — Heinzerling's Chrome Process. — Heinzerling's 
 Second Chrome Process. — Vanderstraaten's Process. 
 
 We have been tempted to adopt the above heading to dis- 
 tinguish the processes about to be described from the ordi- 
 nary processes of tanning, to which they may be said to 
 have no resemblance. Whether the manufacture of leather 
 by other agents than tannin will ever become really suc- 
 cessful is a question which time alone can decide.* We 
 know that alum and salt, as employed in the process of 
 tawing, produce a certain effect upon the skins of smaller 
 animals — as the calf, sheep, goat, &c. — which renders 
 them suitable for certain purposes to which leather, properly 
 so called, would be wholly unfit ; but whether a substitute 
 for tannic acid in the manufacture of leather from heavy 
 hides will ever be discovered, is a matter upon which few 
 will venture to prophesy " onless they know," as Artemus 
 Ward put it. Many attempts have been made in this 
 direction, and we may hazard the prediction that even if 
 a better article could be produced without the agency of 
 tannin, it would take a very long time before the world 
 — so long accustomed to the smell of tan — would believe 
 in it. 
 
 From the numerous processes which have been patented, 
 we select several which have to some extent commanded 
 attention, and at least one of which has been worked upon 
 a practical scale: we allude to what is known as the 
 chrome-tanned leather process of Dr. Heinzerling, carried 
 out by the Eglinton Chemical Company, of Glasgow. 
 
 * The chrome process is now an acknowledged commercial success for 
 most of the lighter kinds of upper leather, and is also used to some 
 extent for harness and belting leather. — Ed. Fifth Edition. 
 
CHEMICAL TANNING. 261 
 
 Knapp's Processes. — I. By this process, which, was 
 patented in 1877, an oxide salt of iron is prepared in the 
 following manner : To a boiling solution of green vitriol 
 (sulphate of iron) as much nitric acid is added as will 
 thoroughly oxidise the same. The effervescence which 
 takes place being over, the operation is reversed, green 
 vitriol being added to the solution now containing the 
 iron oxide ; the second ebullition or effervescence caused 
 by this operation having subsided, the compound has now 
 a syrupy consistence, and is of a yellow-red colour. If it 
 be slowly evaporated, there remains the dry iron oxide 
 salt as an, orange-red transparent varnish. Basic sulphate 
 of iron manufactured in this way is very different in its 
 physical properties from that of commerce and described 
 in chemical books. This latter does not give a syrupy 
 solution, and is of a much darker colour — a brown-yellow 
 — and decomposes on being boiled in an aqueous solution. 
 On the other hand, the preparation above described may 
 be boiled in a solution of 30° to 40° Baume without decom- 
 posing, and is in reality copiously taken up by the skins 
 of animals. 
 
 II. To carry out this process, the hides are treated with 
 the above iron salt in the following way : — 
 
 First Dressing. — To prepare the hides, they are placed 
 in a cold solution of the iron oxide salt, and the dressing 
 is thus completed in two, or at the most four, days, accord- 
 ing to the quantity of skins or hides treated at once. 
 Relaying the skins, handling, and other like operations 
 are dispensed with. 
 
 Currying. — After the skins have been tanned (!) with 
 the iron salt solution, they are treated with fats and 
 greases in a liquid state, and with a new "iron soap" 
 described further on. The greases are dissolved in the 
 manner now in use, and the leather soaked with them, or 
 " stuffed," after the skins have been sufficiently dried. In 
 this manner the present expensive and tedious hand mani- 
 pulation, which makes the value of leather so dependent on 
 the skill and attention of the workmen, is quite done away 
 with ; that is to say, the greasing of the leather by hand 
 
262 LEATHER MANUFACTURE. 
 
 with greases, fat, and like substances, the hanging up in 
 the drying-room, the tramping in the drum, and the 
 working off of the superabundant greases, is thus done 
 away with. Besides the greases now in use, the inventor 
 employs stearine and paraffin, which are chemically dis- 
 solved in the usual way. By the use of fats in combina- 
 tion with the iron solution, the substances used for greasing 
 the leather are united in such a way on the fibres of the 
 skin as to form an " iron soap," which is an entirely new 
 product. 
 
 The iron soap is produced by precipitating soap from its 
 solution by means of the afore-mentioned iron salt solu- 
 tion. The iron soap, combined or not with fatty emulsions, 
 is worked into the leather by means of a drum. This 
 drum consists of a tramping drum, which revolves round 
 a hollow axle, this latter being connected with a blower 
 by a pipe. The blower drives the air through the hollow 
 axle, and through pipes to the circumference of the 
 tramping drum, and through the hides. 
 
 III. In this process a solution of sulphate of peroxide 
 of iron is produced, which acts in the same manner as the 
 solution before described, but with better effect in tanning. 
 Moreover, it is chemically a different compound. This 
 solution is produced by adding equivalent quantities of 
 sulphuric acid and nitrate of soda, instead of nitric acid, to 
 the boiling solution of the sulphate of iron. With the 
 exception of these substitutions, this solution is to be 
 treated in the same way as before. The solution differs 
 from the former chiefly by the soda of the nitrate of soda 
 entering into the new compound as a constituent part, 
 along with the peroxide of iron and the sulphuric acid. 
 
 IY. In this process the inventor treats the leather with 
 albuminous matters, as blood, &c, in such a way that they 
 form a precipitate and compound with the peroxide of iron 
 of the "tanning" salt before described. 
 
 Heinzerling's Chrome Process. — The hides are un- 
 h aired and soaked in the usual way, after which they are 
 placed in a solution of from 1 to 5 per cent, of acid or 
 neutral chromate of potash, chromate of soda, or chromate 
 
CHEMICAL TANNING. 263 
 
 of magnesia, and from 1 to 10 per cent, of alum, or a 
 corresponding quantity of sulphate of alumina. To these 
 may be added from 1 to 10 per cent, of chloride of sodium 
 (common salt). In this bath the skins are left a longer or 
 shorter time, according to their texture and thickness. 
 After the hides have been in the solution for some days, a 
 small percentage of yellow or red prussiate of potash is 
 added, or may be introduced at the commencement of the 
 operation. The prussiate of potash is preferably used for 
 leather which is afterwards to be blackened, and may be 
 dispensed with for other leather. In order to fix the 
 tanning. (!) stuffs in the leather, manipulated as above 
 described, the hides should be placed for a short time in a 
 solution consisting of 1 or 2 per cent, of chloride of barium, 
 1 or 2 per cent, of acetate of lead, or the same proportion 
 of soap. The hides can be dried in the usual manner. 
 
 The smooth, damp hides are next dipped for a short 
 time in stearine, paraffin, chrysene or naphthaline, resin, 
 or other like stuffs, the same having been dissolved in 
 benzine, photogen, or other like solvents. To the above 
 may be added some carbolic acid or thyme oil. The 
 greasing can be effected as usual. The new leather is said 
 to be practically watertight, and when required, is made 
 much softer and more lasting than ordinary leather, while 
 the cost is stated to be much lower than by the bark 
 process. 
 
 Heinzerling's Second Chrome Process — In this pro- 
 cess the inventor employs other chrome compounds than 
 those mentioned in the preceding process, as also certain 
 other substances which he has found to be effective in 
 preparing leather by his method. He says, " I have found, 
 too, in experimenting, that there are many chrome com- 
 pounds besides chromate of potash or magnesia that are 
 effective. Thus, chromic acid, the other soluble chromates, 
 especially those of ammonium, aluminium, and iron, or 
 the sulphate, chloride, acetate, and other soluble chromium 
 salts, are all efficacious for the purpose of converting skins 
 or hides into leather. I also find that the precipitation 
 of soft white neutral mineral material in the pores of the 
 
264 LEATHER MANUFACTURE. 
 
 leather is very advantageous in preserving it, improving 
 its colour, and making it impervious to moisture. Further, 
 that the addition of such salts or oxides as the sulphates 
 of copper, manganese, and zinc, chloride and borate of 
 zinc, tungstate of sodium or of potassium, sulphate or 
 chloride of protoxide or sesquioxide of iron, and oxide 
 of manganese, improve the texture, durability, and colour 
 of the leather." The inventor then gives the process as 
 actually practised by him in Germany, and which is, we 
 presume, the same as that which has been adopted by the 
 Eglinton Chemical Company, of Glasgow. 
 
 "The hides being unhaired in the usual manner, I put 
 them first in a weak, and after a few days in a stronger 
 solution of a soluble chromate or chromic acid. To this 
 solution I add a soluble salt of aluminium, or the soluble 
 hydrated oxide which is formed when carbonate of soda is 
 added to a solution of alum. The quantity of aluminous 
 matter in solution depends on the texture of the hides, 
 the density of leather required, and the salts used ; it 
 varies, therefore, from nothing to say four parts by weight 
 of oxide of aluminium to one hundred of water. The 
 quantity of chromium salt used varies from half to five 
 parts to one hundred of water. In the first pit both the 
 chromic and aluminous materials are weak, especially the 
 latter. While in succeeding pits the chrome does not vary 
 much, that of the aluminous matter varies widely, sole and 
 other hard leathers requiring large quantities, whereas 
 washleather and thin uppers require none, or very little. 
 During the cold season the pits can be moderately heated, 
 say 30° C. (86° Fahr.) The hides are left in this chrome 
 and aluminous solution, with or without the addition of 
 any of the above-mentioned metallic salts useful for im- 
 proving the colour or for tanning, from one to twenty days, 
 according to size, texture, and thickness of the hides, 
 until they are perfectly converted. Their progress and 
 complete conversion may be easily tested by cutting off a 
 piece and seeing if the tanning liquor has thoroughly 
 penetrated it. After this they are put into a solution of, 
 say from three to eight per cent, of a soluble carbonate, 
 
CHEMICAL TANNING. 265 
 
 such as carbonate of sodium or potassium, or a solution of 
 soluble soap, say three to six per cent., in order to fix super- 
 ficially the tanning materials. In some cases it is advan- 
 tageous to use, instead of the above bath, a soluble barium 
 salt, such as the chloride, especially when alum or other 
 sulphates have been largely used. 
 
 " Instead of treating the hides with carbonate of sodium 
 or soap in solution, as before mentioned, in some cases it 
 may be advantageous to use albuminous matter, such as 
 the serum of blood, either dissolved in acids or alkalies, or 
 in the solid state, finely divided, as it is used in the kid 
 leather manufactories. The hides are either immersed for 
 a certain time till the matter has entered superficially, if a 
 solution be used, or tramped in a tramping tun for an 
 hour, in order to facilitate the mechanical entering of the 
 albuminous matter. 
 
 " The hides intended for upper or belt leather are now 
 dried till they are merely damp, and then stretched ; those 
 for sole leather are made quite dry. They are then put 
 into a solution of paraffin, stearine, colophony, or the like 
 (dissolved in any suitable solvent, such as benzole or pho- 
 togen), or into vegetable or animal wax, or such stuff as 
 that formed from treating rape or linseed oil with ten to 
 eighteen per cent, of chloride of sulphur, or the solid 
 soluble residues which are obtained in petroleum and 
 paraffin refineries, or varnish and birch- tar oil ; the above 
 solution is heated from 26° to 38° C. (about 76° to 100° F.) in 
 a water-bath before and whilst the hides are in. The hides 
 are kept in this bath preferably at from 28° to 30° C. (about 
 86° F.) for from one to three days, according to size, texture, 
 and thickness ; they are then exposed to the light for 
 twenty-five to sixty days, until the stearine, paraffin, colo- 
 phony, or other hydro-carbon used appears oxidised 
 throughout Upper and belt leather can be greased a 
 second time if required with the usual substances or 
 with vaseline. The above-described stuffs may be also 
 used in the melted state if they are fusible at a low tem- 
 perature. 
 
 "After a certain quantity of hides have been tanned, it 
 
266 LEATHER MANUFACTURE. 
 
 will be found advantageous, instead of adding soluble 
 aluminous salts, to add a quantity (proportional to the 
 acids set free) of basic aluminium compounds got by in- 
 complete precipitation of aluminium salts with carbonate 
 of sodium or ammonium, or of hydrate of alumina. The 
 tanning liquor should be analysed from time to time, and 
 the mixture kept up to standard chemical composition." 
 
 Vanderstraaten's Process. — The following is a brief 
 outline of the process, the inventor being a Belgian tan- 
 ner : — The hides, after being cleansed from all materials 
 incidental to the removal of the hair, are put into a bath 
 of vegetable tannin of a certain strength, which prepares 
 them for the succeeding treatment. The bath is made 
 from valonia or similar vegetable substances, and if twelve 
 hides are to be treated at one operation, in a vat holding 
 about six cubic metres, five kilogrammes of valonia are 
 required. This is first boiled in order to extract all the 
 tannin. The hides remain in this bath one day, and 
 another day in a second bath, which is made a little 
 stronger than the first. The baths can be used over again 
 by adding fresh material until they are of the desired 
 strength. This first tanning gives to the leather an iron- 
 grey colour. The second operation is performed by means 
 of bichromate of potash, which turns the iron-grey 
 colour into a mahogany-brown. If a lighter shade is 
 desired, half the valonia of the first process is replaced by 
 a corresponding quantity of mimosa-bark. The colour of 
 the leather can thus be determined at the will of the 
 tanner by varying the quantity of tanning material, the 
 strength of the mixture, and the time consumed in the 
 operation. The hides, which are so far only superficially 
 tanned, are then immersed in a solution of either alum, 
 sulphate of silicon, chromate of potash, salts of iron, or 
 other similar astringent agents. 
 
 The inventor claims no right to any of the tanning 
 processes by minerals, but confines himself to the following, 
 preferring the use of bichromate of potash ; the hides are 
 immersed in a weak solution of this salt, and frequently 
 taken out and turned, so that the chemical action which 
 
CHEMICAL TANNING. 267 
 
 produces the grain and colour may be uniform. For this 
 purpose one or two hours are generally sufficient. If the 
 operation is successful, a fine grain, soft to the touch, is 
 formed, and a moderate swelling can be seen. The colour 
 becomes permanent, and can no longer be changed. In 
 the first weak bath they are suspended and subjected to 
 a gentle motion ; here they remain until the tanning 
 material has thoroughly penetrated the skin, which gene- 
 rally occurs after from twelve to fifteen days. The hides 
 are then taken out, thoroughly washed, and subjected to 
 strong hydraulic pressure, by which means most of the 
 chrome, liquor is forced out of the leather, while some of 
 it remains, and this has to be rendered insoluble, which is 
 done by a gelatine treatment. The hides, as soon as they 
 leave the press, are dipped into a bath of hot gelatine, 
 made from the offal of fresh leather, until they are 
 thoroughly impregnated with it, and after this are placed 
 in an agitator for about an hour, by which time the gelatine 
 will have been absorbed by the leather. This treatment 
 renders both the bichromate of potash and the gelatine 
 insoluble, and strengthens the leather by replacing the 
 natural gelatine which had been extracted in the earlier 
 operations of the process. 
 
CHAPTER XXII. 
 
 MISCELLANEO US PB CESSES. 
 
 Indian Method of Preparing Elk-skins. — Old Irish Process of Tanning. — 
 Tanning Nets, Sails, and Cordage. — Glycerine in Tanning. — Bleach- 
 ing Leather. 
 
 Indian Method of Preparing Elk-skins. — Immediately 
 after the skin is removed from the animal it is spread out 
 to dry. The brains are then removed and also dried in 
 the sun upon the grass. When the hunting season is 
 over, the women prepare the hides by soaking them first 
 in water, and afterwards taking off the hair with an old 
 knife. The hides are then put into a large earthenware 
 vessel containing water, and the brains are then added 
 and the vessel heated to about 95°, by which operation 
 they become very well cleansed. The skins are next 
 wrung out and spread upon a kind of rack formed of two 
 upright posts, with two sticks placed horizontally. With 
 the assistance of ropes, the women spread them very well, 
 and during the drying they rub them continually with a 
 stone or round piece of wood, to assist in getting rid of 
 the water and grease, till they are quite dry. In one day 
 a woman can prepare from eight to ten skins. 
 
 Old Irish Process of Tanning. — This consisted in 
 utilising the heath, which grows abundantly in Ireland, 
 as a tanning material. The heath was put into a large 
 cauldron full of water and allowed to boil for about three 
 hours, by which time the tanning principle was exhausted. 
 The liquor was afterwards drawn off into large vats and 
 
MISCELLANEOUS PROCESSES. 269 
 
 the material again treated with water as before. When 
 this last liquor had cooled down to about 95°, the skins 
 were first immersed in this, and afterwards in liquor of 
 increasing strength. In using the liquors the temperature 
 should not exceed 95°. A very good leather was produced 
 by this process. 
 
 Tanning Nets, Sails, and Cordage. — The following 
 method of preserving and increasing the strength of nets, 
 sails, and cordage was patented many years ago. A 
 hundred pounds of oak branches and the same quantity of 
 tan are boiled in eighty-nine gallons of water, until it is 
 reduced to seventy-one gallons. The solid materials are 
 then taken out, and the articles to be tanned are deposited 
 in the liquid, care being taken that they are entirely 
 covered by it, and do not rest upon the bottom of the 
 vessel. They are boiled for three hours, and are then 
 taken out and dried. This, though a true tanning process, 
 can scarcely be likened to the ordinary ones for preparing 
 leather, since its object is a combination of tannin and 
 extractive matter with vegetable substances, which are 
 very different from the gelatine of skin. According to 
 Millet, linen which had been steeped in an oak-bark 
 liquor at 150° Fahr. for two or three days, remained 
 unaltered in a damp cellar for ten years, while an 
 untanned piece entirely rotted under similar circum- 
 stances. 
 
 Glycerine in Tanning. — M. Mene, after first observing 
 that glycerine is a substance which has been found by 
 experience to be useful as a means of increasing the elas- 
 ticity and strength of leather, states that hides, first partly 
 tanned by the usual process, may be greatly improved, 
 especially if required for machine belts, by being soaked 
 for some time in glycerine. 
 
 Bleaching Leather. — One might naturally think that 
 when leather possesses all the characteristics of solidity, 
 firmness, and toughness, being perfectly tanned through- 
 out its entire substance, that its colour would be a matter 
 of little concern. That this is not so, however, is well 
 known, and any divergence from the Ian colour proper 
 
270 LEATHER MANUFACTURE. 
 
 is sure to create a prejudice agaiust the leather, be it 
 ever so good in all other qualities. This is specially so 
 in the case of hemlock-tanned leather, which, unless pre- 
 pared with more than ordinary care, or combined with 
 other tanning materials to reduce its natural redness, 
 presents a colour which, in the eyes of those accustomed 
 to the colour of oak-tanned leather, is objectionable in 
 the extreme. To overcome this well-known prejudice 
 against hemlock tannage, many ingenious persons have 
 turned their attention, with the result that certain 
 bleaching processes have been introduced into the United 
 States, for the details of which we are indebted to 
 Mr. Jackson Schultz, who, however, does not commend 
 this system of tampering with leather in the processes of 
 finishing. 
 
 By one process of bleaching sugar of lead and sulphuric 
 acid are employed. "The practice is to dip the sides 
 alternately, first into the bath of the one and then into 
 the other, until the colouring matter of the hemlock is 
 fully removed. This bleaching process gives an imme- 
 diate, that is almost magical, result ; but when the finished 
 leather is exposed to the air and light for any considerable 
 time, the delicate pink and cream colour turns to a ' murky 
 brown,' and is in all respects a most objectionable finish. 
 The only natural and honest bleaching process known to 
 the writer is that of ' sumac baths.' After the hemlock 
 sides have been cleansed of all extraneous matter by the 
 most effective mechanical device known, they must then 
 be hung in a vat of warm sumac liquor, and plunged fre- 
 quently for one day — even a few hours will sensibly affect 
 the colour. Usually one bag of Virginia sumac will 
 suffice for a pack of one hundred sides. This process will 
 cost about five dollars for a pack, or five cents per side 
 weighing 15 lbs. to 20 lbs. The sumac liquor forms a 
 vegetable acid, which acts most kindly on the grain of 
 hemlock slaughter leather, not only removing (neutra- 
 lising) the colour, but softening the grain, and contributes 
 very much to the whiteness and clearness of the buff." 
 Mr. Schultz says that hemlock leather thus treated will 
 
MISCELLANEOUS PROCESSES. 271 
 
 retain the improved colour for a long time, and " never go 
 back to that muddy and objectionable colour so common 
 with other bleaching processes." 
 
 " As it is the acid which effects the object sought," Mr. 
 Schultz observes, " the sumac should be retained long after 
 the tannin has departed. As a mere tanning agent it is 
 only valuable, as all goat and sheep skin tanners compre- 
 hend, while it is fresh, and before the acid forms. But for 
 the purpose of bleaching hemlock leather it is questionable 
 whether the old cast-off sumac of the morocco dresser is 
 not quite as valuable as new sumac." To this Mr. Schultz 
 adds an important suggestion which the users of hemlock 
 will doubtless appreciate. " Slaughter hemlock leather, 
 tanned with liquors of moderate strength, say 16° to 20°, 
 will produce a colour that is between the lemon and the 
 orange, and if to this we add the warm sumac process, we 
 have then a colour so nearly a light lemon or flesh colour 
 
 as to meet all the requirements of the best oak 
 
 This process is particularly serviceable on calf and all 
 grain-finished leathers, including harness and bridle. No 
 hemlock tannages will 'take the bleaching' so well 
 without as with this process. With it grain leather can 
 be made to hold its colour almost equal to a pure oak 
 tannage." 
 
 Note. — Sumac is still used extensively for bleaching purposes. Care 
 must, however, be used in its application, otherwise the leather so 
 treated is likely to lose weight. Sumac appears to possess the property 
 of being able to dissolve and withdraw some of the more solid con- 
 stituents of the previous tannins used. — Ed. Fifth Edition. 
 
CHAPTEB XXIII. 
 
 ON THE COST OF AMEBIC AN TANNING. 
 
 Mr. J. Scluiltz on the Cost of Tanning — This obser- 
 vant American authority has entered very fully into the 
 question of the cost of tanning, and with his usual clear- 
 ness of reasoning has shown how variable may be the 
 results obtained by manufacturers working under different 
 conditions or by different methods of tanning. lie ap- 
 proximately estimates the cost of tanning as follows : — 
 
 Hemlock sweat sole leather per lb. from 6 to 7 cents. 
 
 Union lime sole leather „ „ 8 „ 9 „ 
 
 Oak lime leather „ ,, 9 „ 10 ,, 
 
 Oak lime rough leather „ „ 8 „ 9 „ 
 
 Hemlock lime rough leather.... „ „ 6 „ 7 „ 
 
 The cost will differ with the circumstances under which 
 the tanning is conducted. One tanner devotes extra 
 time to the beam work ; another to the finishing ; an- 
 other to the handlers or layers ; the freight and price 
 of bark will vary in different localities, therefore in esti- 
 mating the cost it is to be understood that an average is 
 given. 
 
 One ton (2,240 lbs.) of average hemlock bark will tan 
 200 lbs. of sole leather, with the following exceptions : — 
 1. If the bark is ground and leached imperfectly, or in 
 an extraordinarily perfect manner ; 2. If the leather is 
 tanned with a very strong decoction, and thereby a very 
 large gain is obtained as against very weak liquors and 
 light gain ; 3. Great delays and wastes in applying the 
 tannin, which induce the formation of gallic acid ; or the 
 
COST OF AMERICAN TANNING. 273 
 
 bringing fresh, sweet, strong decoctions into contact with, 
 liquor already containing a large percentage of this acid. 
 These exceptions will vary the result from 180 lbs. to 
 200 lbs. of leather made from one ton of bark. Again, if 
 the weight of the delivered bark is not accurate a loss 
 will accrue from this cause. 
 
 Mr. Schultz attaches great importance to the strength of 
 the liquors employed, as influencing the cost of tanning. 
 He says : " The upper leather tanners of New England, 
 who pay ten to twelve dollars per cord [or ton] for their 
 bark, claim to tan, and probably do tan, from 300 lbs. to 
 400 lbs.- of upper leather with 2,240 lbs. of bark. If we 
 comprehend how this is possible, it will enlighten us as to 
 the point under discussion. The upper leather tanners 
 draw their tanning and colour matter from agents which 
 furnish about 20 per cent, extractive material, while the 
 vigorous sole leather tanner obtains his capital from the 
 7 to 8 per cent, tannin which the bark contains. The 
 tannin gives all the gain added to the gelatine, but the 
 colouring matter permeates the fibre, while cumulative 
 gallic acid holds it from decomposition. Upper leather, 
 then, is not tanned and filled as sole leather is, and 
 to this extent and for this reason bark extract will 
 spread itself over far more fibre when all the extractive 
 matter is employed than when it is manufactured so as to 
 hold only tannin pure and simple. It must be evident 
 that when skins are tanned quickly in strong liquors it is 
 at the expense of the most costly agent (the tannin), 
 while the vegetable extractive (the cheaper material) does 
 not enter the skin to any appreciable extent. Conse- 
 quently, if we are to accept Davy's view, the leather 
 produced, while being extravagantly filled with tannin, 
 will be deficient in one of its most important constituents 
 (extractive), and therefore inferior in quality and of less 
 value than leather which is tanned by slower methods. 
 .... If upper leather and calf skins are to be sold 
 by the pound (waiving the question of quality, especially 
 toughness), then it is evident that these light tannages 
 cannot be afforded. But if sold by measure, then a light 
 
 T 
 
274 LEATHER MANUFACTURE. 
 
 tannage is profitable to both tanner and consumer under 
 proper circumstances." 
 
 The above observations are introduced to solve the ques- 
 tion whether a sole leather tanner who tans by the pound 
 can afford to make heavy gains for his employer. One 
 tanner makes 160 lbs. and another 170 lbs. of leather from 
 100 lbs. of hides, "Are they," asks Mr. Schultz, "entitled 
 to the same pay per pound ? Is the cost to each propor- 
 tionate ? The argument on the one side is as follows : — 
 It costs a certain sum to work in, handle, and finish a 
 given lot of leather, whether of heavy or light tannage; 
 the cost of the bark being alone considered, it cannot 
 exceed, and most usually falls short of, the price received 
 for tanning, even though the price be as low as six cents 
 per pound. The sole leather problem is then, in fact, but 
 the upper leather question over again, which would ask 
 and determine the following : Can a customer afford to tan 
 rough leather for less per pound than sole leather, less the 
 finishing ? " He does not consider it an answer to say 
 that they do tan it for less, or that small tan-yards, with- 
 out much interest to pay, pursue the trade successfully, 
 while the argument on the other side is that "heavy gains 
 cannot be made with strong decoctions ; strong liquor can- 
 not be obtained unless more or less waste is permitted — 
 waste in the liquor itself, and more strength lost in leach- 
 ing. Besides, the actual net added weight costs more than 
 is received, which is calculated as follows : — 
 
 Original weight of hide 100 lbs. 
 
 Less hair, grease, fat, &c 15 „ 
 
 Net gelatine and animal fibre 85 lbs. 
 
 "Now, whether this product is raised to 160 lbs. or 
 175 lbs. is a question of mere intrinsic cost of the pure 
 tannin, icliich is capable of combining with the gelatine. 
 In the one case 75 lbs. is required, and in the other 90 lbs. 
 The cost of these respective factors made from bark at 
 six dollars per cord would be (on the theory on which we 
 are proceeding) fully eight cents per pound, since in both 
 cases we start with the hide capital of 85 lbs. It may be 
 
COST OF AMERICAN TANNING. 275 
 
 assumed that there is a discrepancy between the theoretical 
 and practical percentage of tannin obtainable from bark. 
 We know that 2,240 lbs. of hemlock bark will make only 
 200 lbs. of leather. Chemists tell us, however, that there 
 is 8 per cent, of tannin in this bark, consequently there 
 is in this ton of bark 156 80-100 lbs., which, combined with 
 85 lbs. of gelatine, should give 241 80-100 lbs. of leather 
 [without reckoning the vegetable extractive ?] . What has 
 become of this 71 lbs. of lost tannin? " 
 
 May we not venture to suggest that while a consider- 
 able proportion of the lost tannin is converted into gallic 
 acid, a further portion is exhausted (especially when the 
 liquors are made with hot water) by combining with the 
 fibre of the bark — tanning it, in fact ? 
 
 Mr. Schultz gives the following as the probable cost of 
 each item in the production of hemlock leather : — 
 
 Cost of bark (hemlock) per lb 3 cents. 
 
 Cost of soaking, milling, sweating and beam work .... 1 cent. 
 
 Yard work, including handling, laying away, &c ^ „ 
 
 Finishing, including drying, rolling, &c | ,, 
 
 Insurance, interest on tanning and bark | ,, 
 
 Freight to and from the market 1 ,, 
 
 Administration 1 
 
 Total 7 cents. 
 
CHAPTER XXIV. 
 MANUFACTURE OF LIGHT LEATHERS. 
 
 Eussia Leather. — Count Kartstoff's Description of Russia Leather Manu- 
 facture. — Smoking Skins. — Another Method of Preparing Russia 
 Leather. — Black Russia Leather. — Yults Russia Leather. — Morocco 
 Leather. — Sumao Tanning. — Imitation Morocco Leather. — Skiver. — 
 Cordovan Leather. — Roan. — Hungary Leather. — Wallachia Leather. 
 — Barley Dressing — Morfit's Remarks on White Dressing. — Bed 
 Dressing. — Bran Dressing.— Enamelled Leather. 
 
 Russia Leather. — The peculiar characteristics of this 
 famous leather have won for it almost universal admi- 
 ration. Its agreeable perfume, which, like the Tonquin 
 bean, it communicates to other objects placed in contact 
 with it ; its resistance to damp, which fails to produce 
 that mouldiness or vegetable growth to which most 
 leathers are subject under such conditions ; and the well- 
 known fact that insects are repelled even by its odour, have 
 combined to maintain the popularity of this agreeable 
 leather. Although it is generally understood that the 
 true secret of its manufacture has been jealously guarded 
 by those whose interest it is to keep it from the public, the 
 process, more or less accurate, has from time to time been 
 made known by various writers. The process, as given 
 by Ure,* is as follows : — 
 
 " The skins are freed from the hair or fleece by 
 steeping in an ash ley too weak to act upon the animal 
 fibres. They are then rinsed, fulled for a longer or 
 shorter time, according to their nature, and fermented 
 in a proper steep, after having been washed in hot 
 
 * " Dictionary of Arts, Manufactures," &c. 
 
LIGHT LEA TITERS. 277 
 
 water. They are taken out at the end of a week ; but 
 they may be steeped a second time, if deemed necessary, 
 to open their pores. They are now cleaned by working 
 them at the horse [or beam] on both flesh and grain sides. 
 A paste is next composed, for 200 skins, of 38 lbs. of 
 rye- flour, which is set to ferment with leaven. This 
 dough is worked up with a sufficient quantity of water to 
 form a bath for the skins, in which they are soaked for 
 forty- eight hours ; they are then transferred to small 
 tubs, where they remain during fifteen days, after which 
 they are washed at the river. These operations serve to 
 prepare the skins for absorbing the astringent juices with 
 uniformity. A decoctiort of willow-bark (Salix cinerea 
 and S. caprea) being made, the skins are immersed in the 
 boiler whenever the temperature of the liquor is suffi- 
 ciently lowered not to injure the animal fibres, and 
 handled and pressed for half-an-hour. The manipulation 
 is repeated twice daily during the period of a week. The 
 tanning infusion is then renewed, and applied to the 
 same skins for another week, after which, being exposed 
 to the air to dry, they are ready for being dyed, and then 
 curried with the empyreumatic oil of the bark of the 
 birch-tree. To this substance the Russia leather owes its 
 peculiarities. The skins imbibe this oil most equally 
 before they are fully dry. Care must be taken not to 
 apply too much of it, for fear of its passing through and 
 staining the grain side of the leather." The red colour 
 of Russia leather is supposed to be produced by Saunders- 
 wood or Brazil-wood. 
 
 Count Xartstoff's Description of Russia Leather 
 Manufacture. — In a memoir published by Count Karts- 
 toff, the following description of Russia leather tanning is 
 given : — " The dried skins are softened by soaking in 
 water for five or six days in summer and ten or twelve 
 days in winter, and, after being well cleaned, are deprived 
 of hair by steeping in milk of lime — 185 lbs. being 
 mixed with water in a vat eight feet in diameter and seven 
 feet eight inches high. The skins are frequently ex- 
 amined, and when the epidermis and hairs give readily, 
 
278 LEATHER MANUFACTURE. 
 
 they are carefully unhaired upon the beam and then 
 fleshed. Stout hides are not limed, but exposed in a 
 sweating-room, piled upon each other, and sprinkled with 
 salt to prevent decomposition ; bran baths are used for 
 the same purpose for thin and delicate skins. The skins, 
 after being limed, are well soaked, washed, beaten out 
 with the feet, and rinsed in warm water until the last 
 portions of the lime have been removed from them ; they 
 are then raised by steeping for forty-eight hours or more 
 in a vat of the above dimensions, containing a fermented 
 mixture of warm water with 1,100 lbs. of ryemeal, or 
 450 lbs. of oatmeal, 6 lbs. of salt, and a sufficient quantity 
 of leaven. Being thus prej)ared for tanning, they are 
 steeped for a time in a weak infusion of oak or willow 
 bark, the latter being preferred, and are then stratified in 
 a vat with layers of coarse bark, the vat being filled 
 up with the tanning infusion first used, and its contents 
 being pressed down with planks, heavily weighted with 
 stones. 
 
 " The skins are left in this vat from fifteen to twenty- 
 eight days, after which they are removed and again 
 stratified with fresh bark. This operation is repeated 
 from three to six times, according to the nature and 
 quality of the skins, the thinnest kinds only requiring 
 two changes. The stiffness acquired by the leather in 
 tanning is then corrected by soaking them for a day or 
 two in a paste composed of — for every 150 skins of 
 ordinary size — 130 lbs. of oatmeal and 9 lbs. of salt, 
 mixed with warm water. The leather is then well 
 washed, rinsed, and drained, and, while in a partially 
 moist state, is placed upon a large table, flesh side up, and 
 coated with oil. This is composed of a mixture of the oil 
 obtained from sea-calves (which abound in the Caspian 
 Sea) and of the pure oil or tar of birch-bark in varied 
 proportions, according to the nature and quality of the 
 leather, one part of the latter to two parts of the former 
 being generally used. The workman spreads the mix- 
 ture with his hand evenly and uniformly over the surface, 
 and the perfection of this operation depends upon tho 
 
LIGHT LEATHERS. 279 
 
 skill with which it is done. About nine ounces of 
 oil are applied to each skin of medium size. "When 
 oiled, the leather is then stretched out upon cords in an 
 open shed until perfectly dry, and in the winter season 
 is exposed to the cold air, by which its appearance is much 
 improved." 
 
 Smoking Skins. — The Baskirs and Kerguises pre- 
 pare their skins by smoking in lieu of tanning them. 
 They first stretch them out, in their green state, between 
 stakes fixed in the ground, and then remove the hair by 
 scraping with a broken sickle fixed in a wooden handle. 
 They then dig a pit in the ground, proportioned in size 
 to the number of skins to be operated upon, and suspend 
 them across parallel cords which are attached to its edges. 
 A round hole is then dug five feet from the edge of 
 the pit, and is connected with it by a subterranean gutter. 
 The skins are hung upon the cords, the pit is covered 
 over, and a fire of dry rotten wood is lighted in the small 
 hole, the top of which is then closed. The smoke then 
 passes through the connecting gutter into the pit, and the 
 skins are kept exposed to its action for two or three 
 weeks, at the end of which time they are found to have 
 acquired properties similar to those of leather, and, above 
 all, a degree of impermeability which does not exist in 
 that which is tanned.* 
 
 Another Method of Preparing Russia Leather. — 
 This method, described by Yenables, is carried out as 
 follows : — The whitest and most perfect skins being 
 selected, are first soaked in water, then scraped upon the 
 beam, fulled, worked with the pommel, and then oiled 
 upon the hair side with pure fish-oil, and upon the flesh 
 side with a mixture of oil and train-oil scourings. When 
 dry they are again pommeled, washed over upon the hair 
 side with a solution of alum, and then pressed under the 
 cylinder. This cylinder, by which the diamond- shaped 
 grain is given to Russia leather, is made of steel ; it is 
 
 * It is more than probable that this primitive method of curing sMna 
 was practised in the earliest ages, many centuries before the tanning pro- 
 perties of plants were known. — A. W. 
 
28o LEATHER MANUFACTURE. 
 
 about twelve and a half inches long and three inches in 
 diameter, and is covered with a number of close parallel 
 threads or grooves, like those of a screw, but cut perpen- 
 dicular to its axis, and not spirally. The cylinder is 
 filled with stones, and is moved in two directions upon a 
 wooden bench or support by means of a cord passing 
 round a wooden roller with a handle. This cord passes 
 also over two cylinders attached to the floor and a fourth 
 one upon the edge of the bench. The cylinder having the 
 handle upon its axle is divided into two different parts, 
 over which the two extremities of the cord pass in dif- 
 ferent directions, so that two opposite movements can be 
 given to the cylinder by one handle. 
 
 The cylinder is sustained and directed by iron bars 
 placed along the bench upon which it rolls. The skin 
 which is to be grained is placed below it lengthwise upon 
 the bench, and longitudinal grooves are pressed upon its 
 surface by the track of the cylinder. The skin is then 
 removed, and again placed upon the bench, either cross- 
 wise or at an angle, according as it is intended to give it 
 a square or a diamond-shaped grain. When properly 
 grained, a second soak of alum-water is applied, and when 
 nearly dry the Russian oil is spread over the grain side, 
 and the red or black colour is given. The skin is then 
 repeatedly exposed for a short time to the direct rays of 
 a hot sun, until the colour has sufficiently penetrated its 
 substance, when it is fulled, pommeled, sleeked with the 
 round knife, upon the beam, and finally, well rubbed 
 upon the hair side with a hard brush. The chief charac- 
 teristic of the preparation of Russia leather is its impreg- 
 nation with the birch-bark oil, the mode of preparing 
 which is still, in a measure, kept secret. In order that 
 the oil should penetrate the leather properly, the latter 
 must not be either too moist or too dry, but should contain 
 just sufficient water to enable the oil to spread equally 
 over the surface, and be absorbed in proportion as the 
 moisture gradually evaporates. Thus prepared, the leather 
 retains the characteristic odour for a long time. Great 
 care should be taken not to apply an excess of the oil. 
 
LIGHT LEATHERS. 281 
 
 From 12 ozs. to 1 lb. generally suffice for fully impreg- 
 nating a large cow-skin. In the case of leather not dyed, 
 or of Morocco to which it may be desired to impart the 
 odour, only a very small portion should be applied to the 
 flesh side. The composition of the red colour with which 
 Russia leather is commonly stained has not been accu- 
 rately ascertained. It usually contains Brazil-wood, alum, 
 and some other ingredients. It is not very durable,* and 
 does not resist the action of boiling water or of potassa, 
 though it generally remains unaltered in the air. Other 
 d} T es of better quality are sometimes used, which enhance 
 the price of the leather. 
 
 Black Russia Leather is prepared in the same way 
 as the other, and is stained by repeated applications of 
 the acetate of .iron. 
 
 Yufts, or Youfts Russia Leather. — Wagner describes 
 the method of preparing this leather, the name of which 
 is derived from the Russian word yufte, signifying a pair, 
 because, as it is supposed, the hides are sewn together in 
 pairs previous to the process of tanning. The hides 
 usually prepared for leather in Russia are those of young 
 cattle ; sometimes, however, the hides of horses and skins 
 of sheep, goats, and calves are employed. The operations 
 for preparing yufts are — 1. Cleaning of the hides with 
 lime as usual. 2. Swelling or raising in a bath of sour 
 wheat liquor, exhausted tan liquor, or mixture of dog's 
 dung and. water. 3. Tanning with, various kinds of 
 willows, fir and birch bark being also used. The pelts are 
 first treated for some days in partly exhausted bark, and 
 are next put into tanning tanks, along with bark, or 
 sometimes into a warm infusion of the tanning materials. 
 The tanning occupies from five to six weeks. 4. The 
 tanned hides are placed on the planing block to drain, 
 and are next impregnated with oil of birch. The oil is 
 rubbed into the hides on the flesh side, and when 
 thoroughly impregnated the hides are stretched until 
 
 * In some specimens of Kussia leather binding in the Patent Office 
 Library, London, not only has the colour faded, but the leather appears 
 to be undergoing a process of decay. — Ed. Fifth Edition. 
 
282 LEATHER MANUFACTURE. 
 
 they become soft and supple ; they are next rubbed on the 
 grain side with a solution of alum, and then grained and 
 dried. The dry hides are dyed in pairs, sewn together in 
 the form of a bag, into which the dye material is poured. 
 When a red colour is desired, the dye is prepared from 
 sandal-wood, with the addition of potash or soda. By 
 more recent methods, the hides are dyed by being 
 brushed over five or six times with the dyeing material. 
 After dyeing, the leather is dressed in the usual way. 
 
 Oil of Birch. — The oil of birch employed in the pre- 
 paration of Russia leather is obtained by dry distillation. . 
 The whitish membranous epidermis of the birch, stripped 
 of its woody matter, is placed in a copper still, to which 
 is connected a pipe for conducting the volatile products to 
 a receiver containing cold water. About 60 per cent, of 
 the weight of the bark is in this way obtained in the 
 form of a crude oil. 
 
 Chevreul investigated the chemical nature of the oil of 
 birch, and found that its odoriferous property is due to 
 a peculiar compound, to which he has given the name of 
 betuline from betula, the birch-tree. 
 
 Morocco Leather. — Not less famous than the leather 
 just noticed is that known as Morocco leather. Unlike 
 the former, however, this kind of leather is very exten- 
 sively manufactured both in this country and on the Con- 
 tinent, and forms an important branch of industry with 
 the manufacturers of light and fancy leathers. True 
 Morocco leather is goat skin tanned, and dyed on the grain 
 side. The skins of sheep, however, are extensively em- 
 ployed for conversion into a cheaper variety of this 
 leather, and are, after tanning, dyed in a great number of 
 different colours. 
 
 Morocco leather prepared from goat skins is exten- 
 sively used for carriage-linings, chair-covers, for superior 
 bookbinding, pocketbooks, purses, and many other useful 
 purposes. This leather is remarkable for its glossy, 
 wrinkled, and fibrous appearance. The goat skins from 
 which Morocco leather is manufactured in England are 
 largely imported from Switzerland, the East Indies, Cape 
 
LIGHT LEATHERS. 283 
 
 of Good Hope, Memel, Mogadore, Asia Minor, Germany, 
 and other parts of the world. The skins vary con- 
 siderably in size and thickness, as also in quality, and are 
 imported with the hair on. 
 
 An important feature in the preparation of Morocco 
 leather is the tanning process, which is effected with 
 sumac in a very peculiar way, as will be explained 
 further on. The goat skins are first soaked, or drenched, 
 in water for several days, to soften them, and are next 
 broken — that is scraped or rubbed on the beam, on the 
 flesh side, to further soften them and to remove flesh}^ 
 matters which would interfere with the action of the lime 
 liquor to which they are afterwards subjected. They are 
 then placed in old lime liquor for two or three days, after 
 which they are handled or " drawn," by removing them 
 from the pits by means of small tongs (Fig. 48), and 
 
 Fig. 48. 
 
 placing them in a heap for a few hours. They are next 
 transferred to a " middling " lime liquor for several days, 
 being frequently drawn as before, and the skins are finally 
 placed in pits containing strong lime liquor, in which 
 they are allowed to remain with frequent handling or 
 " drawing," until the epidermis readily yields to the 
 touch. The liming generally occupies from about ten to 
 fourteen days in summer, but in winter a longer period 
 is required. 
 
 Unhairing and Fleshing. — The goat skins, when ready 
 for unhairing and fleshing, are removed to the jlcshing 
 shop, or beam house, in which a series of teams, placed at 
 equal distances from each other, are arranged opposite the 
 windows of the apartment, whereby the workmen are 
 enabled to perform their operations in a good light. Each 
 goat skin is laid smoothly on the beam, with the hair side 
 upward, and the beam man, standing behind the beam, 
 scrapes the hair from the pelt by means of the two-handled 
 unhairing knife. Fig. 49 illustrates the operation. After 
 
284 LEATHER MANUFACTURE. 
 
 being unhaired the goat skins are again steeped in lime 
 liquor for two or three days, after which they are 
 fleshed on the beam. The lengthened sfceepings in the 
 lime-pits naturally cause the lime to enter into the pores 
 of the skin, and therefore its entire removal is the next 
 most important step, so that the tanning principle of the 
 sumac may fully enter into the fibrous structure of the 
 pelt. For this purpose a mixture composed of dogs' 
 dung and water is employed. This mixture, called the 
 pure, is of an alkaline nature, and has the effect of convert- 
 
 Ffc. 49. 
 
 ing the lime within the pores of the skins into soluble salts, 
 which eventually become removed by washing and the 
 mechanical processes of scraping or scudding. A great 
 many attempts have been made to provide a less disagree- 
 able substitute for the excrement of dogs, but the fact 
 that this material is still extensively used, especially in 
 England, would indicate that as yet no efficient substitute 
 has been found. 
 
 Scudding. — After remaining in the pure for some time, 
 the skins are removed, and after being steeped they are 
 
LIGHT LEATHERS. 2S5 
 
 forcibly scraped, or scudded, as it is termed, with a blunt 
 two-bandied knife, botb on the grain and flesh side, by 
 which the remaining lime and albuminous matters are 
 forced out of the pelt. They are then again steeped for a 
 short time, and the effect of the various operations to which 
 they have been submitted is that the pores of the skins are 
 opened and free from all such matters as would prevent the 
 proper absorption of the tanning principle. 
 
 Sumac Tanning. — The peculiar nature of this tanning 
 material, which is of a yellow colour, renders it necessary 
 to apply it in such a way that its action upon the pelts 
 shall be perfectly uniform, a result which would not be at- 
 tained if the skins were immersed in an infusion of the 
 material in the same way as in ordinary bark tanning. In 
 order, therefore, to insure perfect uniformity in the action 
 of the sumac tannin, the following system is adopted : — 
 The pelts, after passing through the various operations 
 above described, are transferred to an apartment in which 
 they are sewn up into bags by women — each skin forming 
 a bag — with the grain side outward, a small opening at 
 the hinder part only being left for the introduction of a 
 funnel. At Messrs. Bevingtons' Bermondsey works these 
 bags are now made by the sewing-machine. When the 
 bags are made they are thrown into a vessel of water and 
 examined to ascertain if they are properly sewn and free 
 from holes. They are next taken to the sumac tub, which 
 is a large shallow vessel about fifteen feet in diameter, 
 and which is filled with hot water containing a little 
 sumac. Close to this tub is a smaller vessel containing 
 a strong solution of sumac. 
 
 The method of filling the bags with the stronger 
 solution is as follows, and is performed by two men and a 
 boy. Taking their places by the side of the smaller tub, 
 the lad takes one of the bags and inserts the neck of a 
 funnel in its opening, when one of the workmen nearly 
 fills the bag through the funnel with the strong sumac 
 solution by means of a ladle (Fig. 50). The second man 
 then takes the bag from the funnel and inflates it with 
 his breath, after which he closes the aperture by tying it 
 
286 
 
 LEATHER MANUFACTURE. 
 
 with a piece of string. The bag, in its distended condition, 
 is perfectly free from wrinkles, the presence of which 
 would interfere with the uniform action of the tanning 
 material, and its contained air enables the bag to float in 
 the liquor of the larger vessel. All the bags, as they 
 are filled, are thrown into this larger tub, in which they 
 float like bladders, and they are kept in constant motion 
 for about three hours in this way : two men, one on each 
 
 Fig. 50. 
 
 side of the tub, take each a wooden paddle, which they 
 work to and fro in the solution, causing the floating bags 
 to roll gently over and over, by which the sumac solution 
 in the bags becomes uniformly diffused over their inner 
 surface, and eventually permeates the entire substance of 
 the skin ; the absorption of the tanning principle is greatly 
 aided by the warm temperature of the solution in which 
 the skins are floated. The goat skins being very thin, are 
 effectually tanned by this method in a few hours. In 
 Fig. 50 a workman is also seen in the act of moving the 
 floating bags about in the sumac tub. During the 
 process of sumaching the bags are removed once from 
 the tub, and are piled up in a heap upon a rack near 
 the tub, and by means of their own weight the sumac 
 solution is forced through the pores of the skins. After 
 
LIGHT LEATHERS. 287 
 
 this they are subjected to another sumaching operation, 
 and are then once more piled up in a heap to acquire 
 the necessary pressing, by which time the operation is 
 complete. 
 
 The bags are now removed to another apartment, where 
 the stitching is undone and the sediment which remains 
 from the sumac is removed from the interior. This refuse 
 generally consists partly of yellowish sandy matter with 
 which the material had been adulterated before importation 
 from Sicily. This waste, being of no farther use in tan- 
 ning, is sold as manure. The tanned pelts are next 
 thoroughly washed, and are then laid out smoothly upon 
 a sloping board ; they are next " struck," as it is termed 
 — that is, scraped and rubbed until they are perfectly 
 smooth. They are then hung up in a loft to dry. When 
 dried they are said to be in the crust, and present a some- 
 what shrivelled and irregular appearance. To render 
 them smooth, preparatory to dyeing them, the skins are 
 first wetted, and then once more struck, or smoothed, as 
 before, after which they are ready for the dyeing-house. 
 The process of dyeing Morocco and other leathers is given 
 in another chapter. 
 
 Imitation Morocco Leather. — This is chiefly prepared 
 from sheep and calf skins, and is extensively used for bags, 
 bookbinding, chair-covers, and many other useful pur- 
 poses, and as now manufactured bears a close resemblance 
 to the true Morocco. The sheep skins, before they come 
 into the tanner's possession, are deprived of their wool by 
 a class of manufacturers called fellmongers, who receive the 
 skins in the condition in which they leave the slaughter- 
 houses. After the skins are fellmongered, the wool is dis- 
 posed of to the ivoolstapler, and the fells, as they are 
 termed, to the tanner and manufacturers of parchment. 
 
 The unwoolled sheep skins or fells are treated much in 
 the same way as goat skins ; since the skin of the sheep, 
 however, is naturally of a more greasy and oily nature 
 than that of the goat, it requires very careful treatment to 
 remove these greasy matters before being submitted to the 
 operation of sumac tanning ; the skins are therefore first 
 
288 LEATHER MANUFACTURE. 
 
 submitted to powerful hydraulic pressure, by which the 
 greasy matters are forced out from the pores of the skin. 
 They are then subjected to the same treatment as goat 
 skins, excepting that they are tanned by immersion in 
 sumac liquor instead of being sewn up into the form of 
 bags, as in the case of goat skins. 
 
 Skiver. — When sheep skins are split by means of the 
 splitting machine, the grain splits, as they are called, are 
 converted into a thin variety of leather called skiver, which 
 is much used for common bookbinding, pocket-books, hat 
 linings, and other purposes requiring a cheap but strong 
 leather. The flesh splits, as we have before said, are em- 
 ployed for making inferior kinds of chamois or oiled 
 leather. The thin skivers, being more readily acted 
 upon by the sumac tan than goat skins, are not sewn up 
 into bags, but are immersed in the sumac tub in an open 
 state, and are tanned in a very short time. 
 
 Cordovan Leather. — This leather derives its name from 
 the city of Cordova, in Spain, where it is supposed to have 
 been originally prepared by the Moors. It has a very fine 
 and beautiful grain, and is dyed in every variety of shade 
 and colour. The finest qualities are imported from the 
 Levant, but those of Spain, France, Hungary, and Ger- 
 many are also highly esteemed. The skins employed in 
 the manufacture of Cordovan leather are those of the goat 
 and dog, and sometimes also hog skins are used, but the 
 leather prepared from goat skins is preferred. The skins 
 after being cleaned and drenched in water, are limed, after 
 which they are again steeped in water for eight to fifteen 
 days, during which period they are repeatedly worked by 
 treading upon them with the feet. At the end of a fort- 
 night they are steeped in a lukewarm mixture of dogs' 
 dung and water, next into a bran bath, and after removal 
 from the latter, the skins are then stretched, pressed 
 between two boards, and rubbed with common salt. They 
 are next immersed in a bath prepared from figs and water. 
 Only skins that are to be coloured black are dyed after 
 being tanned. Black leather is tanned in liquor of extract 
 of oak-bark ; that of lighter colour in ooze prepared from 
 
LIGHT LEATHERS. 289 
 
 extracts of sumac and nut-galls. When the operation 
 of tanning is complete the leather is withdrawn, taking 
 with it as little liquor as possible, and spread in the 
 shade, when it must be rubbed on the bloom with oil of 
 sesame before the sides have become perfectly dry. 
 After the oil is laid on, drying in the shade is allowed 
 to be completed, when the skins are folded on the flesh 
 side. When it is desired to give the Cordovan a rough 
 appearance, the surface may be rubbed with a blunt knife 
 immediately after spreading. In many parts of Russia 
 wormwood (Artemisia absinthium) is employed to fix the 
 colour in the leather. If, for example, it is desired to dye 
 the leather black, a decoction of wormwood is mixed with 
 powdered cochineal, and alum is then added. 
 
 In the island of Cyprus, Cordovans are dyed red in the 
 following manner : — The skins, generally about fifty at a 
 time, are placed in a fig bath ; they are then passed into 
 a strong solution of alum heated to about the temperature 
 of new milk ; they are afterwards hung upon poles to drain, 
 and are next stretched to expel as much moisture as pos- 
 sible ; finally, the skins are placed on a table, and after 
 being uniformly stretched, the red colour is applied with a 
 cotton rag. The colouring-matter is prepared by taking 
 ground cochineal and boiling it in soft water in a well- 
 tinned kettle, and during the ebullition 5 ozs. of powdered 
 alum are added for every 5 ozs. of cochineal, and the liquor 
 boils until reduced to one-sixth or one-eighth by evapora- 
 tion, when it is passed through a filter. The skins are 
 coated four or five times with this preparation, and after 
 being placed in the tanning liquor are submitted to the 
 operations of dressing. 
 
 In Hungary and Transylvania, where the manufacturers 
 of Cordovan produce goods which are highly esteemed, the 
 red colour is laid on in a different manner. When the skins 
 have been properly prepared, they are fastened together in 
 pairs, in the form of bags, with the sides to be coloured 
 inside. Into an opening in this bag the warm colouring- 
 matter is poured, and in order to insure uniformity of its 
 action the bag is occasionally agitated by being rolled about. 
 
 U 
 
290 LEATHER MANUFACTURE. 
 
 Koan. — This leather is prepared from sheep skins, much 
 in the same way as Morocco, being tanned with sumac, 
 but in the after processes of currying it is not grained like 
 the latter. 
 
 Hungary Leather. — The mode of preparing this leather, 
 which is peculiar, consists in impregnating strong hides 
 with alum, common salt, and tallow, by a quick process, 
 which is generally complete in about two months. The 
 process is thus given by Ure : — " The workshop is divided 
 into two parts. 1. A shed on the side of a stream, fur- 
 nished with wooden horses, fleshing-knives, and other 
 small tools. In one corner is a furnace with a boiler for 
 dissolving the alum, a vat for immersing the hides in the 
 solution, and several tubs. 2. A chamber 6 feet high by 
 15 feet square, capable of being made very tight for pre- 
 serving the heat. In one corner is a copper boiler, of 
 sufficient size to contain 170 lbs. of tallow. In the middle 
 of the stove is a square stone slab, upon which an iron 
 grate is placed about a yard square. This is covered with 
 charcoal. At each side of the stove are large tables, which 
 occupy its whole length, and on which the leather is spread 
 to receive the grease. The upper part below the ceiling is 
 filled with poles for hanging the leather upon to be heated. 
 The door is made to shut perfectly close. The first opera- 
 tions are analogous to those of tanning and tawing, the 
 skins being washed, cut in halves, shaved, and steeped for 
 twenty-four hours in the river. They are cleaned with 
 5 or 6 lbs. of alum and 3 \ lbs. of salt for a piece of hide 
 which weighs 70 to 80 lbs. The common salt softens the 
 effect of the alum, attracts moisture from the air, and pre- 
 serves the suppleness of the skin. When the alum and salt 
 are dissolved, hot water is poured upon the hides placed in 
 a vat, and they are trampled upon by a workman walking 
 repeatedly from one end of the vat to the other. They 
 are then transferred into a similar vat containing hot 
 water, and similarly trampled upon. They are next steeped 
 for eight days in alum-water. The same round of opera- 
 tions is repeated a second time. 
 
LIGHT LEATHERS. 291 
 
 " The skins are now dried either in the air or a stove- 
 room, but before being quite dry they are doubled together, 
 well stretched to take out the wrinkles, and piled up. When 
 dry they are again trampled to open the pores, as well as to 
 render the skins pliant, after which they are whitened by 
 exposure to the sun. Tallow of inferior quality is employed 
 for greasing the leather. With this view the piece is 
 hung upon the poles in the close stove-room, then laid 
 upon the table and besmeared with the tallow melted till 
 it begins to crumble. This piece is laid on another table, is 
 there covered with a second similarly greased, and so forth. 
 Three pounds of fat are commonly employed for one piece 
 of leather. When the thirty strips, or fifteen hides, passed 
 through the grease in one operation are completed, two 
 workmen take the first piece in their hands, and stretch it 
 over the burning charcoal on the grate for a minute, with 
 the flesh side to the fire. The rest are passed over the 
 flame in like manner. After flaming, the pieces are suc- 
 cessively laid on an inclined table exposed to the fire, 
 where they are covered with a cloth. They are finally 
 slung upon poles in the air to dry ; if the weather be 
 warm, they are suspended only during the night, so as 
 to favour the hardening of the grease. Instead of the 
 alum bath, ]VL Curaudau has employed with advantage a 
 steep of dilute sulphuric acid." 
 
 Wallachia Leather. — The following; is an abridgment 
 of Morfit's description of the Wallachian method. This 
 leather is prepared by barley dressings in a simple warm 
 vat, and the skins are unhaired by a fermentative process 
 instead of the usual liming. Dry hides, after being 
 softened in water, are first trampled upon and then 
 worked on the flesh side upon the beam, to render them 
 pliant ; they are next steeped in water for a short time, 
 and then hung up to drain. They are now examined, to 
 ascertain if the hair comes away easily ; for in hot climates 
 during the summer-time this is effected without any other 
 process of depilation. When fresh skins are employed, 
 fermentation is resorted to for loosening the hair. After 
 
2 9 2 LEATHER MANUFACTURE. 
 
 removing the tail, horns, and ears, the skins are salted 
 without being soaked. The salting consists in sprinkling 
 each large hide with four to six pounds of salt, alum, and 
 saltpetre ; the hides are then folded and stacked in a heap, 
 which is then covered with litter. After a short time the 
 hides become heated, and they are turned over once or 
 twice a day, so as to render the fermentative process uniform 
 throughout. When it is found that the hair yields to the 
 touch, the operation of unhairing is promptly performed, 
 since if the skins were allowed to remain for too long a 
 period under the influence of the fermenting process, the 
 pelt would suffer decomposition and consequent injury. 
 In cases where it is inconvenient to unhair the skins 
 "immediately they are in the proper condition, they are 
 steeped in water for one or two days, but not longer; 
 otherwise putrefaction would ensue. 
 
 Raising. — When the depilation is effected, the pelts are 
 treated in a bath composed as follows : — For seven skins, 
 each averaging 80 lbs., 20 lbs. of flour are made into leaven, 
 which is worked up into a pasty condition with water ; to 
 this a gill and a half of vinegar is added to promote the 
 acetous fermentation. The preparation of the leaven 
 occupies about twenty-four hours, and the vessel in which 
 it is placed must be kept in a warm place, well covered 
 up for three or four days. The tub for seven skins is 
 about five and a quarter feet across, and three and a quarter 
 feet high, and must be perfectly clean and free from any 
 matter which would check the progress of the fermenta- 
 tion. The tub is filled with water, with which the leaven 
 is well incorporated by stirring. Six or seven bucket- 
 fuls of the liquor are then put into a kettle and boiled, and 
 a portion of this used to make a uniform paste with ground 
 barley, and this is afterwards thinned with cold water 
 until it has a syrupy consistence. This compound is next 
 boiled until it froths, and is kept constantly stirred with a 
 wooden paddle. When the compound has frothed up 
 three times, it is ladled into the tub to be employed for 
 the dressing, and cooled down by stirring continually in 
 one direction, until the hand can readily bear its tern- 
 
LIGHT LEATHERS. 293 
 
 perature. Six pounds of salt are then added and well 
 stirred in, and the tub is then covered up and allowed 
 to repose for a fortnight to sour, the mixture being 
 stirred twice a day during this time, and the vessel being 
 immediately covered after each stirring. 
 
 The skins being removed from the rinsing water, are 
 strung in threes with a cord and thrown into the tub, 
 where they are allowed to remain for four or five days, 
 being, however, drawn twice daily and left to drain for a 
 minute, and then returned to the tub. "When the skins 
 are sufficiently soft, they are next fleshed and unh aired, 
 and are then rinsed in clean water, after which they are 
 hung up to drain for twenty-four hours. While the above 
 operations are in progress, a second leaven is prepared 
 from 16 lbs. of meal, and fermented in the same 
 way as the former. The clear sour liquor of the first 
 dressing is now transferred to a second tub, in which the 
 dressing is completed. Six or seven bucketfuls of the 
 clear sour liquor are taken from each tub, and a portion 
 stirred up with 50 lbs. of ground barley — about 8 lbs. for 
 each skin. The remaining hot water is then added 
 gradually, and the whole gently boiled and added to the 
 new dressings and well stirred in. One or two bucket- 
 fuls are taken out and heated to near the boiling-point. 
 Another leaven, prepared from 8 lbs. of meal, is then 
 diffused through the tubs, and from 4 to 6 lbs. of salt 
 added to each, with stirring. The process may be sim- 
 plified by making one steep instead of two, by using at 
 first 30 lbs. of leaven, 120 lbs. of barley, and 10 lbs. of 
 salt for each dressing of six hides. 
 
 Relative to barley dressing, Morfit says, "It must be 
 observed that, by the ordinary process, the tanners use at 
 one time, in their first new dressings, just twice the 
 quantity of barley that would be employed here [Wal~ 
 lachia], and, moreover, when their first new dressing is 
 not sufficient, they are obliged to make a second, which 
 renders the process more tedious and expensive than that 
 of Wallachia. It is also necessary to say that, on the 
 addition of salt, the dressing must always be well stirred, 
 
294 LEATHER MANUFACTURE. 
 
 and two or three bucketfuls of the liquor drawn out from 
 each and kept warm, to be poured into the vat in order 
 to maintain the temperature. Several other bucketfuls are 
 also taken out and poured into a reserve tub, so that no 
 more liquor may remain in each dressing than is sufficient 
 to cover the skins subjected to its action. Many tanners 
 believe that it is better to make the whole composition 
 at once, for independently of loss of time and fuel, the 
 complement made with the new quantity of barley may 
 retard the progress of fermentation, and the liquor must 
 be heated to a temperature which would be injurious to 
 the skins." 
 
 There are several methods of preparing the composition 
 for barley dressing : 1, from barley or rye meal, without 
 leaven, prepared overnight with boiling water ; 2, from 
 equal parts of barleymeal and leaven, thinned with water, 
 and heated to boiling just previous to putting in the skins ; 
 3, from wheat bran, in the proportion of half a bushel per 
 hide, weakened with hot water, and after a day's fermen- 
 tation mixed with 1 lb. of salt for each skin ; 4, from 
 leaven of barley or rye, in the proportion of from 6 to 8 lbs. 
 of meal per hide. When the leaven rises, it must be 
 thinned with water at 86° Fahr., and the salt added just 
 before the skins are immersed. 
 
 Barley Dressing. — When the fermentation is well 
 established, which is indicated by the liquor becoming 
 sour, the dressings, as they are called, are ready for the 
 skins, which are taken from the hangers and passed 
 through the liquor several times, so as to equalise the tem- 
 perature. They are now left upon the cover of the tub for 
 a few minutes to drain ; the liquor is then stirred, and 
 the skins returned to the tubs, which are then covered, 
 and the temperature of the dressings is kept up by 
 additions of the hot reserve liquors. In a quarter of an 
 hour the skins are again drawn out and left to drain as 
 before, after which they are replaced in the tub, and half 
 an hour after are again withdrawn and left to drain for 
 a quarter of an hour. They are then replaced in the tub, 
 again removed, and drained for twenty minutes. In the 
 
LIGHT LEATHERS. 295 
 
 fifth, dipping the skins are left in the bath for an hour, 
 after which they are drained for half an hour, and then 
 returned to the tub. These operations are repeated in all 
 about eight times. If, on the following day, the hides are 
 not sufficiently raised, they are dipped several times more 
 until the required condition is attained. The heat of the 
 dressings must be kept at from 105° to 120° Fahr. by 
 additions of hot liquor. 
 
 Morfit's Remarks on White Dressing. — " Experience 
 has proved that the action of the white dressing is com- 
 pleted in about thirty-six hours ; the acetic fermentation 
 which ^s established so expands the hides that they become 
 as thick as the leather into which they are about to be con- 
 verted. Care must be taken not to leave them any longer 
 in the liquor after this point has been attained, for it in- 
 jures the leather, a result which also takes place if the 
 liquor is too strong. After the removal of the skins from 
 the liquor, the latter must be reserved for new dressing, 
 for which purpose it must be heated with a complement 
 somewhat stronger than the first. This acid liquor greatly 
 facilitates the fermentation of the new composition, which 
 sours rapidly. In this manner, when the white dressings 
 are once in train, they may be kept at one-half the expense 
 of flour, time, and money." 
 
 When removed from the dressings, the hides are left to 
 drain on the cover, and when cooled are soaked in water 
 for a few moments to remove the viscid coating derived 
 from the barley, and they are then again drained. 
 
 Red Dressing. — The skins are now subjected to what 
 is termed the red dressing, preparatory to their being 
 placed in the tan-vats. This dressing is made by putting 
 about 40 lbs. of crushed bark, mixed with water, into a 
 tub. Into this the hides are then placed, and allowed 
 to remain for several hours, when they are taken out and 
 drained for a few minutes. A few hours after further 
 immersion this operation is repeated, but previous to 
 returning the skins to the vat the last time an addition 
 of 40 lbs. more crushed bark is made, and this is well 
 stirred in. On the mornings of the second and third 
 
296 LEATHER MANUFACTURE. 
 
 days, 24 lbs. of bark are added, the skins taken out 
 thrice daily, half an hour being allowed for each drain- 
 ing. On the fourth day the skins are drained morning 
 and evening, forty-five minutes being allowed each time. 
 On the morning of the fifth day the hides are taken out, 
 and while draining the liquor is well stirred. The hides 
 are then put back, hair side upward, and a few handfuls 
 of crushed bark thrown in between each skin, and on the 
 top of the last one, which should have its flesh side upward, 
 a layer of bark is spread. The skins are now left for eight 
 to ten days, then removed, rinsed in clean water, and put 
 into the tan- vats. 
 
 Bran Dressing. — Some tanners contend that the red 
 dressings may be omitted if the white dressings are made 
 with bran. The unanimous opinion of many tanners 
 whom we have consulted on the subject is in favour of red 
 dressings. The bran dressings are prepared either hot or 
 cold. In the first, the leaven is prepared from yeast, or 
 made with 1 to \\ lbs. of wheat or rye flour per hide, and 
 kept at a moderate temperature, which quickly sours. 
 After the skins have been soaked and cleansed, they are 
 lleshed and rinsed in water. They are then put into a 
 bath composed of bran liquor as follows : A sufficient 
 quantity of water for all the skins is boiled with bran, in 
 the proportion of 7 or 8 lbs. for each skin ; the boiler 
 is then covered, and when the liquor has sufficiently fer- 
 mented, which is known by the bran rising to the sur- 
 face, the liquor is transferred to a vat in which the skins 
 were previously deposited. While the skins are getting 
 warmed, another quantity of water is heated until it sim- 
 mers, when to this is added the fermented liquor first pre- 
 pared. The skins are then taken out of the vat, and the 
 fresh mixture is poured in, with the addition of salt in the 
 proportion of rather more than 1 lb. per skin, and the 
 whole is well stirred. The skins are now placed in the 
 vat, where they are allowed to remain for about six hours. 
 They are then removed and drained for a short time, and a 
 portion of reheated liquor put into the vat. The same 
 operations are repeated every six hours during two days. 
 
LIGHT LEATHERS. 297 
 
 When the hair is loosened it is removed in the usual way. 
 after which the skins are fleshed and soaked in cold water 
 for a quarter of an hour ; they are then returned to the 
 vat, and allowed to remain until sufficiently raised. By 
 reheating a portion of the liquor from time to time, and 
 keeping the vessel covered, the raising will generally be 
 effected by the end of three days. The skins are now 
 rinsed and left in soak for some hours in fresh water, when 
 they are ready for the subsequent tanning operations. — 
 Morfit. 
 
 Enamelled Leather. — This variety of leather, which 
 for a long period was known under the title of "patent 
 leather," is prepared from calf, seal, and other skins, with 
 a varnish composed of drying oil, vegetable black, and 
 Prussian blue. The skin is first stretched on a fiat board, 
 and every trace of grease is then removed from the surface 
 by means of a paste made with fuller's earth and water, 
 which is afterwards thoroughly removed by rubbing. 
 The skin is then ready to receive the first coat of varnish, 
 which is composed of Prussian blue (that which contains 
 some alumina) 5 ounces ; drying oil, 1 gallon. These 
 being well mixed or ground together, are boiled to the 
 consistence of "single size;" and when cold, a small 
 quantity of vegetable black is added and ground up with 
 the mixture. The first coat is given by pouring some of 
 the varnish over the leather, and then spreading it over 
 thinly with a kind of scraper until the entire surface is 
 evenly coated. The leather is then placed in a drying 
 stove, and when sufficiently set is placed aside to cool ; it 
 is afterwards polished with finely-powdered pumice. A 
 second coating is then given with the varnish, in which a 
 little pure Prussian blue has previously been mixed, and 
 the leather is again stoved and polished with pumice as 
 before. For the third coat the varnish consists of a similar 
 mixture, but the oil is boiled until it strings well, and a 
 little more Prussian blue and vegetable black are added, 
 the varnishing, stoving, and polishing being pursued as 
 before. The last coat, or finish, is given with a varnish 
 like the third, with the addition of | lb. of pure dark- 
 
298 LEATHER MANUFACTURE. 
 
 coloured Prussian blue and \ lb. of pure vegetable black 
 per gallon, and to this a little oil, copal, or amber varnish 
 are sometimes added. The heat of the stove or oven is 
 usually about 120° Fahr. for enamelled skins, as those of 
 calf and seal intended for uppers, and 175° Fahr. to 180° 
 Fahr. for stout " Japan leather." The exposure in the 
 stove is commonly from six to ten hours. 
 
CHAPTER XXV. 
 
 DYEING LEATHER. 
 
 Dyeing Morocco Leather. — Dyeing with Aniline Colours. — Dyeing Kid 
 Leather for Boots. — Bath Dyeing. — Dyeing on a Flat Surface. — 
 Aniline Colours in Glove Dyeing. — Dyeing with Pure Aniline 
 Colours. 
 
 Dyeing Morocco Leather. — After the goat skins have 
 been sumached, opened, and well washed, they are spread 
 out upon a sloping board and struck out, that is scraped and 
 rubbed out as smooth as possible, after which they are 
 hung up in the loft to dry. When thoroughly dried they 
 are in a hard and shrivelled condition, and are said to be 
 " in the crust." To bring the skins to a proper condition 
 to receive the dye, they are first softened or " seasoned " 
 in water, after which they are struck out or smoothed 
 again, when they are ready for dyeing. Since Morocco 
 leather only requires to be coloured or dyed on one side, 
 it is usual to lay two skins of the same size in close con- 
 tact, flesh to flesh, before dyeing, so that the dye liquor 
 may only penetrate one side of each skin. For red Mo- 
 rocco, the skins are first mordanted either with a solu- 
 tion of tin or with alum water, after which they are 
 immersed in a bath prepared from cochineal, boiled in 
 water, with a little alum or tartar added, the liquor 
 being filtered through a linen cloth before use. After 
 about half an hour the skins are withdrawn and then 
 subjected to another immersion in the cochineal bath. 
 They are then rinsed, drained, oiled on the grain side, 
 and hung up to dry, after which they are transferred to 
 the currier. 
 
3oo LEATHER MANUFACTURE. 
 
 Black Dye is given by brushing over the grain side a 
 red solution of acetate of iron. For blue, the cold indigo 
 vat is used. Violet is produced by first dyeing a pale blue, 
 and afterwards dipping in the red cochineal vat. For green, 
 Saxon blue, followed by a yellow dye, produced by the 
 chopped roots of barberry. Puce colour is produced by 
 logwood, with a little alum added ; olive, by first passing 
 the skins through a weak solution of copperas, and next 
 through the decoction of barberry root containing a little 
 Saxon blue. After dyeing, the skins are rinsed and 
 drained, after which they are laid flat on a table, and 
 smeared over with linseed oil on the grain side by means 
 of a sponge, to render the surface glossy when curried, and 
 also to prevent them from drying too rapidly and thus be- 
 coming hard and flinty. 
 
 Dyeing with Aniline Colours. — Since the introduction 
 of the famous aniline or coal-tar dyes, many hues have 
 been given to leathers which could not be produced with 
 equal facility by means of the ordinary dye stuffs. The 
 great brilliancy of the aniline dyes, and the readiness with 
 which they combine with animal substances, render them 
 most potent auxiliaries in the dyeing-room, and with ne- 
 cessary care in their employment they are capable of pro- 
 ducing a great variety of tones or shades of exquisite 
 brilliancy. 
 
 The Gerber Zeitung, to which the leather trades are in- 
 debted for much valuable information, has recently contri- 
 buted a series of memoirs upon dyeing leather with aniline 
 colours, which cannot fail to prove highly serviceable to 
 those who are engaged in this important branch of manu- 
 facture. These papers having been reproduced in the 
 Dyer and Calico Printer,* we are indebted to that useful 
 journal for the following extracts : — 
 
 Dyeing Kid Leather for Boots. — The subject is con- 
 sidered in two main divisions, namely, the dyeing of 
 leather for boots and for gloves. The leather used for the 
 first-named purpose is usually that which is too imperfect 
 for the manufacture of gloves. The first process is soften- 
 * The Dyer and Calico Printer, February, March, and June, 1884. 
 
DYEING LEATHER. 301 
 
 ing the skins in water. The dyeing is effected by two 
 methods — plunging, or dyeing on the flat surface. In the 
 latter case the skin is white on the flesh side. In the old 
 process of dyeing with wood colours, it was considered 
 necessary to adopt the plunging method for all delicate 
 shades, but with aniline colours this is not necessary. 
 With any dilute dye-wood decoctions it is impossible to 
 produce on the skin by means of brushing a full and uni- 
 form tone of colour, but with aniline colours it is quite 
 possible to produce on a flat surface the most delicate 
 shades obtainable by plunging. The skins must be 
 stretched out on a flat surface to free them as much as 
 possible from moisture. 
 
 As mordants for the so-called kid leather dyeing the 
 following acids are used : sulphuric, phosphoric, tartaric, 
 oxalic, tannic, and acetic acids. Amongst the alkalies 
 used as mordants are soda, potash, and ammonia. Acids 
 must be used with all blue aniline colours, with most 
 greens, as well as with many yellows and browns. Alka- 
 lies are used with all red aniline dyes and with kindred 
 shades. 
 
 Bath Dyeing. — The modes of dyeing are, as we have 
 said, bath dyeing and dyeing on a flat surface. The first 
 is carried out by filtering a solution of the aniline colour 
 made with hot water. A portion of this solution (of 5 to 
 10 per cent, strength) is poured into lukewarm water in a 
 vat, and the skins are placed singly in it, a workman tread- 
 ing them down with his feet and keeping them in motion. 
 When the colour has been taken up by the skins, they are 
 removed and subjected to slight pressure, and more colour- 
 ing matter added to the bath, the process being repeated 
 till the skins have taken the desired shade. To determine 
 what the colour of any particular stage will be when 
 dried, a small piece is cut from a corner and put in a linen 
 cloth which is repeatedly wrung, when the ultimate shade 
 after drying and dressing will be seen with relative ac- 
 curacy. The skins are now taken out and slightly pressed, 
 the colouring liquor is poured off, except a small residue, 
 to which yolks of eggs and salt are added ; the skins are 
 
302 LEATHER MANUFACTURE. 
 
 then replaced and the previous treatment renewed. As 
 this process gives a slightly yellowish tinge, this fact 
 should be kept in view in dyeing the shade in the first 
 instance. The skins are then spread out and allowed to 
 drain, after which they are dried. 
 
 To arrive at the desired shades, such as pink, eosine is 
 taken for a yellowish tinge. 1. For pure pink, eosine 
 two parts, phloxine one part. Pink with a bluish tinge, 
 phloxine two parts, eosine one part. Phloxine for a dis- 
 tinctly bluish tinge in a delicate shade. 2. Straw is pro- 
 duced by the use of naphtholine yellow, and for specially 
 strong shades some methanil yellow. 3. For cream, a 
 very weak solution of naphtholine yellow. 4. Salmon is 
 produced by mixing the latter colour and eosine in the 
 following proportions : For the more reddish shades, 
 eosine two parts, naphtholine yellow one part ; for more 
 yellowish shades, eosine one part, naphtholine yellow one 
 part. Buff, eosine and methanil yellow in equal propor- 
 tions for the more reddish shades, and equal parts of 
 phloxine and methanil yellow for a bluish tinge. For the 
 above colours it is recommended to add some phos- 
 phate of soda to the dyeing-bath, to facilitate the process 
 and impart brilliancy to the colours. 
 
 Dyeing on a Flat Surface is effected by first applying 
 to the stretched- out skin a mordant with a medium soft 
 brush. The colouring substance is then applied with a 
 brush. After two applications the skin is drained so as 
 to allow fresh colouring matter to be taken up. When 
 the skin is sufficiently dyed the excess of colour is 
 removed with water. Draining then follows, and the 
 skin is hung up to dry. 
 
 The following are some of the shades obtained by this 
 method : — 1. Cream : Solution of naphtholine yellow in 
 water one-sixteenth per cent. The skin is mordanted with a 
 solution of phosphate of soda in water (proportion 1 : 100). 
 Three brushes of the above weak solution of dye stuff are 
 applied, the skin being drained after the second brushing. 
 As a coating, a solution of dextrine in water mixed with 
 phosphate of soda may be used : phosphate of soda one 
 
DYEING LEATHER. 303 
 
 part, dextrine two parts, water 100. This coating can be 
 used as a mordant, and produces a silky brilliancy which 
 protects the colour from the influence of the air ; otherwise 
 aniline colours fade, even without the action of light. 2. 
 Straw : Naphtholine yellow one part, water 400 parts. 
 Treat as before. 3. Golden yellow : Methanil yellow one 
 part, water 100 parts. 4. Pink, with yelloxds'h tinge : A 
 solution of eosine made with one-sixteenth' per cent, of 
 eosine. 5. Pink, with bluish tinge : A solution of phloxine 
 (one-sixteenth per cent.). 6. Pure pink: A mixture of 
 the above solutions in equal proportions. 7. Cerise is ob- 
 tained with a one per cent, solution of erythrosine, three 
 or fourTmishes being used in the subsequent process. 8. 
 Sky blue is obtained by means of water-blue D.N. in 
 a half per cent, solution. As a mordant, phosphate of 
 soda in one per cent, solution, to which tartaric acid is 
 added in the proportion of f- oz. to \ oz. for 22 gallons. 
 The following mordant is recommended for all blue 
 and green aniline colours : water 22 gallons, phosphate 
 of soda 2ith lbs., dextrine 2,1th. lbs., tartaric acid f oz. 
 to 1 oz. 9. Imperial blue (cornflower blue) is ob- 
 tained with water -blue D.N. in a one per cent, 
 solution, the process being as in No. 6. Greg in dif- 
 ferent shades is obtained by mordanting as 1 to 7, and 
 maddering with elderberry juice or dogwood-berry juice 
 (two brushes), then as a coating nigrosine or indu- 
 line applied in a one per cent, solution. 10. Green. 
 A light shade is given with new Victoria green, and a 
 darker shade with extra brilliant green. 11. Violet : A 
 one per cent, solution of methyl violet in water. When 
 the skins have been dried they are plunged in water 
 for a few seconds and are then allowed to drain like 
 plates in a rack. A glazing machine may then be used 
 for finish. 
 
 Aniline Colours in Glove Dyeing. — While in the so- 
 called kid leather used for boots aniline colours are the 
 principal dye substances used, it is different with glac6 
 leather, in which they are only adjuncts. The use of 
 aniline colours in dyeing glove-leather is divided into the 
 
3 o4 LEATHER MANUFACTURE. 
 
 following : — a. Dyeing with pure aniline colours, b. 
 Maddering with pure dye-wood or berry-dye solutions, 
 with a coating of aniline, and with the use of various 
 metallic salts for darkening or turning shades, c. The 
 mixing of different wood-dyes as maddering substances, 
 with a coating of aniline, without employing any turning 
 substances, d. A pure or mixed decoction of dye-wood 
 or berries, shaded with aniline dyes. 
 
 Dyeing with Pure Aniline Colours. — The process is 
 almost entirely confined to so-called plunging colours, 
 used to produce the most delicate shades for evening 
 wear, the processes b, c, and d being carried out on a 
 fiat surface. Phosphate of soda, with the addition of 
 a very small quantity of tartaric acid, may be advan- 
 tageously used. The dyeing substance is added to the 
 bath in very small quantities, by which greater purity 
 and regularity of colour are obtained. When the de- 
 sired tone has been arrived at, a little dextrine is put 
 into the bath and a little borax added. The skins are 
 then well worked for five minutes longer, when they 
 are taken out and allowed to drip, and are afterwards 
 pressed. They are then treated with yolk of egg and 
 salt, which must be greater in quantity than for kid 
 leather. The aniline colours used are naphthol yellow, 
 methanil yellow, eosine, phloxine, methyl violet, nigro- 
 sine W., and induline N.N. 
 
 The following table shows how the most usual shades 
 required for opera and evening wear are respectively ob- 
 tained by the old and new methods : — 
 
 Old Method. New Method. 
 
 Cream or Ivory. .Decoction of Persian berries, Naphthol yellow in a very 
 
 with a trace of Brazil wood dilute form. 
 
 Straw Persian berries Naphthol yellow. 
 
 Pink Brazil wood with a little Two parts eosine with one 
 
 cochineal part phloxine. 
 
 Violet Alcoholic extract of logwood Methyl violet. 
 
 Greenish Grey . . Elderberry juice, with a little NigrosineW., with a trace 
 
 carmine indigo of lumiere green. 
 
 Pearl Grey .... Elderberry juice and alco- Two parts nigrosine W. 
 
 holic extract of logwood and one part induline 
 N.N. 
 
DYEING LEATHER. 305 
 
 Old Method. New Method. 
 
 Yellowish Buff . .Persian berries and logwood Four parts naphthol yel- 
 low and one part eosine. 
 Reddish Buff. . . . Persian berries, Brazil wood, Two parts of metbanil 
 (Flesh colour) and cocbineal yellow and one part 
 
 pbloxine. 
 
 In mixing the above solutions, precision in quantities 
 must be observed, and it is recommended to make solutions 
 of the strength of one-tenth per cent., in which there is one 
 gramme (15'43 grains) of dye-stuff to each litre ("22 gallon) 
 of water. It is best to make the solution in a cold state and 
 in bottles of moderate size, so that they can be shaken to 
 prevenl^the particles of dye-stuff from caking. After 
 pressing, the skins are placed in a darkened and heated 
 room well ventilated. The salts used for toning down 
 colours are : copperas (sulphate of iron), sulphate of copper, 
 (bluestone), sulphate of zinc, mixtures of copperas and 
 bluestone, and potash alum, used in 1 per cent, solutions. 
 The reader is referred to articles which appear from time 
 to time in The Leather Trades Review for more elaborate 
 details of aniline dyeing on leather. 
 
CHAPTER XXVI. 
 
 MANUFACTURE OF WHITE LEATHER. 
 
 Tawing as distinguished from Tanning. — Tawing Operations. — Kid 
 Leather : Treatment of Kid Skins. — French Kid Leather. — Imita- 
 tion Kid. — Continental Method of preparing Glove Leather. — Calf 
 Kid for Uppers. — "White Sheep Leather. — Splitting Sheep Skins. 
 
 Tawing, as distinguished from Tanning. — In the pro- 
 cess of tanning, as we have seen, the gelatine of the skin 
 undergoes a chemical change when brought into contact 
 with tannin, by which tanno-gelatine is formed — a sub- 
 stance not only insoluble in water, but which cannot be 
 again separated into its two chief constituents, tannic acid 
 and gelatine, by any known means. In the process of 
 tawing, however, the skins are subjected to the action of 
 alum and salt, which, although they convert the skins into 
 a substance resembling leather in some of its attributes, 
 cannot be said to form a true chemical compound with the 
 gelatine, inasmuch as the three substances — gelatine, alum, 
 and salt — can be again separated by treatment with water, 
 as proved by the researches of Davy. 
 
 The arts of tanning and tawing are therefore perfectly 
 distinct, and have no relation whatever to each other. 
 Some manufacturers of light leathers, however, carry on 
 the process of tanning calf and seal skins, as well as the 
 tawing of goat, kid, sheep, and other small skins. 
 
 Tawing Operations. — The chief operations of tawing 
 are : — 1. Soaking, or steeping in water. 2. Breaking, or 
 scraping on the flesh side. 3. Liming. 4. Unhairing and 
 fleshing. 5. Steering in a Iran-water drench. 6. Working 
 on the beam. 7. Treatment with alum and salt. 8. Egging. 
 
WHITE LEATHER. 3 o 7 
 
 The skins which are subjected to the operations of tawing, 
 or alum-dressing, are those of the kid, the calf, the lamb, 
 and the sheep, the first being employed to produce the 
 well-known kid leather, from which the finest sorts of 
 gloves and uppers of ladies' shoes and boots are made. 
 Lamb skins, when prepared by the processes we are about 
 to describe, form an imitation kid leather, from which the 
 cheaper kinds of " kid " gloves are made. 
 
 Kid Leather : Treatment of Kid Skins. — These skins, 
 which are chiefly imported from Italy, are of very small 
 size, and have the hair on. For leather to be employed 
 for the finest quality of gloves, the skins are obtained from 
 the young goats before they leave the mother to feed on 
 herbage. The imported skins, being in the dry state, are 
 first subjected to the operation of — 
 
 Soaking, or steeping in water, in large tubs or vats, 
 wherein they are allowed to remain for about three days ; 
 at the end of this time the skins have become consideiablv 
 softened, when they are next broken, as it is termed, on the 
 flesh side. 
 
 Breaking. — The skin is laid upon the beam, flesh side 
 upward, and is then forcibly scraped with the blunt two- 
 handled tool (Fig. 5), by which it is put into a better 
 condition for liming. The effect of the scraping or rub- 
 bing is to break down the fleshy matter attached to the 
 skin, which had become hardened during the process of 
 drying, and thus render the skin more readily acted upon 
 by milk of lime. 
 
 Liming. — After the skins have been broken they are 
 immersed for two or three days in "old" lime liquor, 
 being "drawn" occasionally, that is, removed from the 
 pits by means of the small tongs (Fig. 48) and placed in a 
 heap, being allowed there to remain for some time, after 
 which they are steeped in "middling" lime liquor for 
 Several days, and are finally immersed in strong lime 
 liquor, in which they remain, being frequently drawn as 
 before, until the hair can be readily removed from the pelt 
 by the finger. In from ten to fourteen days, according to 
 the temperature of the atmosphere, the skins are ready 
 
308 LEATHER MANUFACTURE. 
 
 for unhairing. When the liming process is complete, the 
 workman passes his thumb along the upper surface of the 
 skin, when the cuticle, with its hair, peels off with perfect 
 ease, exposing the bare pelt or corium. 
 
 Unhairing. — The skins, after being removed from the 
 lime-pits or tanks, are allowed to drain for a short time, 
 when they are removed to the beam-room, where they are 
 submitted to the process of unhairing, after which they 
 are again soaked in lime water for several days. They are 
 next fleshed, by which the pelt is brought to a tolerably 
 clean condition. The lengthened steeping in the lime 
 liquor, however, has the effect of forcing the lime into the 
 pores of the skin to such an extent that, unless this were 
 removed, the materials subsequently employed would not 
 enter into the interior structure of the skin. To remove 
 this lime and to open the pores, the kid skins are immersed 
 in the bran drench. 
 
 The Bran Drench is a mixture of bran and water, con- 
 sisting of about 40 lbs. of bran to 20 gallons of water, 
 which is allowed to undergo what is called acetous fermenta- 
 tion, during which acetic acid is formed. By the action of 
 the vegetable acid the lime within the pores of the pelt is 
 converted into soluble acetate of lime, which is removed by 
 subsequent washings. The skins are steeped in the bran 
 liquor for some days, being frequently turned over, so as 
 to equalise the action of the sour liquor. The branning 
 operation is watched with great care, especially when 
 treating such delicate skins as those of the kid. The 
 branning has the effect of opening the pores of the skin 
 besides "killing" the lime, as it is termed. 
 
 Striking. — When the skins are sufficiently branned they 
 are next struck, or scudded, by being worked on the beam 
 with the blunt knife, by which albuminous matters, and 
 any lime that may still remain within the pores, is effec- 
 tually worked out. The skins are then again steeped in 
 the bran drench for a day or two, after which they are in 
 a condition to undergo the process of aluming. 
 
 Treatment with Alum and Salt. — In this operation the 
 skins are put into a kind of wooden drum or tumbler 
 
WHITE ^EATHER. 
 
 309 
 
 (Fig. 51). This machine, which is furnished with a door, 
 either in its circumference or at one of its ends, through 
 which the skins and alum 
 mixture are thrown, is 
 constructed so as to rotate 
 upon an iron axle with 
 the usual gearing. In the 
 interior of the tumbler 
 are fixed, at equal dis- 
 tances, a series of per- 
 forated breakers, upon 
 which ihe skins, when 
 the machine is in motion, 
 fall, and thus become 
 more intimately brought 
 in contact with the alum 
 mixture. These drums 
 are also used for washing 
 the skins. On each end 
 of the drum are four small holes to admit cold air from 
 without, and to allow the air warmed by the rotary motion 
 of the drum to escape. The materials placed in the drum 
 to act upon the skins for the inferior kinds of leather are 
 alum and salt, in the proportion of about 12 lbs. of alum 
 and 2 \ lbs. of salt to about 12 gallons of water for each 
 200 skins. Sometimes, instead of employing the tumbler, 
 the alum mixture is placed in a tub, and the skins steeped 
 in the solution. Whichever method is adopted, the skins 
 are only subjected to the action of the mixture for about 
 five minutes, by which time the desired effect is produced. 
 Egging — The Emulsion or Paste. — For skins destined 
 to form the finest quality of glove leather, a peculiar kind 
 of emulsion is employed, in which the yolks of eggs form 
 a necessary ingredient. This emulsion is prepared by 
 working up the yolks of eggs, in the proportion of one 
 yolk per skin, with a little flour and water, the whole being 
 vigorously worked up into a thin paste. Into this mixture 
 the skins are put, one by one, and they are trampled upon 
 by the naked feet until the emulsion has become thoroughly 
 
3io 
 
 LEATHER MANUFACTURE. 
 
 are 
 and soft- 
 
 (Fig. 52) 
 
 absorbed. The effect of the aluming and steeping in the 
 emulsion is to whiten and soften them, preventing the 
 latter from hardening under the 
 process of drying. 
 
 Drying. — The tawed shins are 
 next hung upon poles in the dry- 
 ing-room, after which the} 1 
 stretched out, smoothed 
 ened upon the stake. 
 
 Staking. — The stake 
 is a wooden support, at the upper 
 end of which is a blunt steel, semi- 
 circular blade, somewhat like a 
 cheese-knife. The skin, in a nearly 
 dry state, is laid over this, and the 
 workman takes hold of it with both 
 hands and forcibly draws it over 
 the knife in all directions, but more 
 especially from side to side, by 
 which it becomes stretched to its 
 fullest extent, while at the same time all stiffness and 
 rigidity are removed, and it becomes exceedingly soft and 
 pliant. 
 
 French Kid Leather.— The following method of pre- 
 paring this famous leather is thus given by Wagner :* " The 
 so-called Erlanger, or French tawing process, is employed 
 only for the production of the glace, or kid leather, used 
 for making gloves and ball-room shoes. The hair side of 
 the skins intended to be converted into this leather is left 
 unchanged, while as regards wash-leather gloves, which 
 are treated (tanned) with fish oil, the hair side is cut off. 
 The skins intended to be converted into kid leathers are 
 treated with extraordinary care, and thus acquire in a very 
 high degree all the good quality of alum-tanned (or rather 
 tawed) leathers. As these skins are often intended to re- 
 main white, or are dyed with delicate colours, the greatest 
 care is taken to prevent any injury — as, for instance, con- 
 
 * " A Handbook of Chemical Technology." 
 1'h.D. Edited by William Crookcs, F.ll.S. 
 
 By Eudolf Wagner, 
 
WHITE LEATHER. 3" 
 
 tact with oak wood or with iron while wet. Two kinds 
 of skins are employed for conversion into the better varie- 
 ties of kid leather ; one of these, the more expensive, 
 being the skins of young goats fed solely upon milk, the 
 other being lamb skins. Each of these skins yields on an 
 average two pairs of gloves. The leather of which ladies' 
 ball-room shoes are made is obtained from the skins of young 
 calves (so called calf kid). The preliminary operations of 
 preparing this leather are exactly similar to those adopted 
 for ordinary white leather, but the tawing operations are 
 quite different, the skins being put into a peculiar mixture 
 by whicji they are not only tawed, but simultaneously im- 
 pregnated with a sufficient quantity of oil to render them 
 soft and give suppleness. The mixture consists of a paste 
 composed of wheaten flour, yolks of eggs, alum, common 
 salt, and water. The flour, by the gluten it contains, aids 
 the absorption of the alumina compound, and thus assists 
 the real tawing. The starch does not enter into the com- 
 position of the skins, while the yolk of eggs acts by the oil 
 it naturally contains in the state of emulsion, this oil 
 giving the kid leather that suppleness and softness which 
 is so much esteemed in gloves. 
 
 " It appears that emulsions made with almond oil (the 
 so-called sweet oil of almonds, a fixed oil), olive oil, fish 
 oil, and even paraffin, may be advantageously substituted 
 for the yolk of eggs. The skins are thoroughly soaked 
 and kneaded in this mixture, to which, in France, there is 
 sometimes added two to three per cent, of carbolic acid, for 
 the purpose of preventing the too strong heating of the skins 
 when impregnated with the mixture and packed in heaps. 
 The skins are next stretched out by hand and dried as 
 rapidly as possible, by exposure to air. Having been 
 damped, a dozen of the skins are placed between linen 
 cloths and trodden upon to render them soft. After this 
 they are, one by one, planed, dried, and again planed. 
 Either by rubbing with a heavy polished glass disc, or by 
 the appreteur, simultaneously with the application of some 
 white of egg, a solution of gum, or of fine soap, a gloss is 
 given to the skins, the hair side of which is the right or 
 
312 LEATHER MANUFACTURE. 
 
 dyed side. The dyes are applied either by immersion or 
 by brushing over the leather, the latter or English method 
 of dyeing skins being more generally practised." 
 
 Knapp states that very good white leather may be pro- 
 duced by tawing the epidermis from lamb or goat skins in 
 a saturated solution of stearic acid (stearin e) in alcohol, the 
 leather thus produced being very soft, and whiter than 
 ordinary glace leather, besides having a beautiful gloss. 
 
 Imitation Kid. — For preparing this kind of leather 
 lamb skins are emploj^ed. These skins are imported from 
 the shores of the Mediterranean,* " in the wool," as it is 
 termed, and this, being a valuable commodity, is removed 
 with very great care before the operations on the pelt 
 commence. Since the wool would be impaired if the skins 
 were subjected to the process of liming, the skins are sub- 
 mitted to a process of sweating, or putrefactive fermenta- 
 tion, by which the wool becomes loosened from the pelt. 
 
 Sweating. — The skins are first steeped, or drenched, in 
 water for several days, after which they are broken on the 
 flesh side. They are then again steeped, drained, and while 
 still wet are transferred to a close room, sometimes an 
 underground vault, the temperature of which remains nearly 
 uniform all the year round. In this the skins are sus- 
 pended from rails or bars. After a certam time ferment- 
 ation commences, ammonia being given off in considerable 
 quantity, together with a powerful and offensive odour. 
 In about five days the wool becomes loosened from the 
 pelt, but the skins are carefully examined from time to time 
 before the process is complete, as it is of the greatest im- 
 portance that the sweating process should be arrested and 
 the skins withdrawn at the proper period, otherwise the 
 pelt itself would suffer injury from the decomposition 
 which ensues. 
 
 When the sweating is completed, the skins are removed 
 and worked on the beam, or slimed, as it is termed, that is 
 scraped on the flesh side with the beam knife, to remove a 
 slimy matter which exudes from the pores. The wool is 
 
 * These skins generally measure about 20 inches by 12, and each skin 
 produces leather for two pairs of small gloves. 
 
WHITE LEATHER. 313 
 
 then removed, and this is afterwards cleaned and prepared 
 for sale. The unwooled pelts are next steeped in the lime- 
 pit for about a week to " kill " the grease, and after this 
 they are fleshed on the beam. This having been done, 
 they are next placed in a drench of sour bran liquor for 
 several days to remove the lime and open the pores ; they 
 are next treated with the alum mixture, and in all other 
 respects treated in the same way as kid skins. 
 
 Continental Method of preparing Glove Leather. — 
 The substances used are alum and common salt as in the 
 ordinary white tanning, but it is especially necessary to 
 obtain alum free from iron, on which account this is selected 
 in the most careful manner. Wheat flour and the yolks 
 of eggs are then added in the following proportions. For 
 a thousand skins of young goats or lambs, 25 lbs. of alum 
 free from iron and 11 lbs. of common salt are dissolved 
 in 150 lbs. of water. Next, a firm stiff dough is prepared 
 from the yolks of 500 fresh eggs and 50 lbs. of the very 
 finest wheat flour, to which only enough of the alum solu- 
 tion is added to enable the dough to be mixed. When the 
 egg-yolks and the flour have become very thoroughly 
 and intimately blended, the remainder of the solution is 
 gradually added, forming a thin pap of about the consist- 
 ence of honey. This pap is called nahrung (nourishment, 
 or food). Instead of the egg-yolks it is very common in 
 southern France to employ pure olive oil, but even there, 
 where hens are scarce and eggs dear, the eggs are employed 
 by way of assistance when the finest kind of leather is to 
 be prepared. The nahrung, or tawing paste, is placed 
 in a vat, in which the skins are laid, being turned over 
 several times, soaked through, and then a couple of per- 
 sons with well- cleaned bare feet go into the vat and tramp 
 about for an hour until the liquid part of the paste has 
 been entirely taken up. After this has been effected other 
 workmen relieve the tired trampers, and repeat the opera- 
 tion with the skins which have already absorbed sufficient 
 of the liquor. Next follows the stretching of the leather. 
 Two workmen grasp a skin with both hands and pull it in 
 every direction as powerfully as possible without tearing 
 
3H LEATHER MANUFACTURE. 
 
 it. The skins are then dried quickly and given their 
 lustre by covering the grain side with the ichites of eggs 
 and rubbing them with a small disc of glass. 
 
 The wheat flour used in making the paste has no effect 
 upon the skin, and is only employed as a medium for dis- 
 tributing the egg, oil, and alum evenly and more finely, 
 and to present the alum as well as the oil (which are both 
 necessary for the tawing) in the form of an emulsion, 
 not too thin, otherwise the action upon the skin would be 
 too rapid, and therefore irregular. The claim that the 
 flour serves, by means of its starch constituent, to give the 
 leather a white colour, could only be made by one who was 
 entirely unacquainted with the matter. The starch flour 
 does not dye white ; it covers the outer surface with white 
 flakes, which fall off as soon as it dries. 
 
 This fine leather has yet to be coloured ; for this pur- 
 pose it is sorted into five or six different grades. Those 
 skins which are entirely free from faults are allowed to 
 remain white, being used for white gloves. Since these 
 are the most delicate, they must also be the most free from 
 faults. The second sort are employed for very clear 
 colours, as yellow, chamois, flesh colour, or rose-red. The 
 third sort is coloured dark yellow, lilac, or sea-green ; and 
 the fourth or stronger colours, brown, violet, ash-grey, and 
 green. The fifth grade is employed for all dark shades, 
 and the sixth for black. The colour is applied either by 
 immersing the wdiole skin, as is done with the lighter 
 colours, or bjr rubbing the dye upon the grain side, which 
 is the practice with the lighter tints, in order that the 
 colour may not come off upon the hand when it becomes 
 warm. The clear colours do not " crock " so easily, and 
 the little that does come off is hardly noticeable. — Gerber 
 Courier. 
 
 Calf Kid for Uppers. — The preliminary operations in the 
 preparation of this famous leather are : 1, Soaking and 
 cleansing; 2, Liming; 3, Unhairing and fleshing; 4, 
 Puring ; 5, Scudding ; 6, Drenching. The skins are 
 next subjected to a series of operations termed dressing, 
 the most important being : 1, Alum dressing ; 2, Drying; 
 
WHITE LEATHER. 315 
 
 3, Seasoning ; 4, Staking ; 5, Shaving ; 6, Egging ; 7, 
 Dj^eing and finishing. 
 
 Soaking and Liming. — As the skins are received from 
 the slaughter-house, they are thrown into a large tub of 
 water to cleanse them from filthy matters, after which they 
 are placed in the old lime-pits, in which they are handled 
 as usual, after which they are treated in a stronger or 
 " middle " lime, in which they are again handled ; and 
 are afterwards immersed in strong lime, where they are 
 allowed to remain (being drawn each day and returned to 
 the same pit) until the hair is sufficiently loosened, when 
 the skins are drawn and allowed to drain, after which 
 they are removed to the beam-house to be unhaired and 
 fleshed. 
 
 *Unhairing and Fleshing by Machinery. — "We had re- 
 cently the pleasure, through the courtesy of Mr. John S. 
 Carlaw, of Blue Anchor Lane, Bermondsej^ of witnessing 
 the unhairing and fleshing of calf skins by a machine of 
 remarkable effectiveness. The blades of this machine, 
 which is called the "Duplex Unhairing and Fleshing Ma- 
 chine " (Janson's patent), are the invention of M. V. Gal- 
 lien, and so constructed as to act upon the two surfaces of a 
 skin, removing hair and flesh simultaneously, without in the 
 least degree injuring the pelt. The inventor says : " The 
 object of this invention is to give such an edge to the 
 knives or blades of revolving cylinders in machinery, for 
 shaving or otherwise treating hides and skins, that there 
 may be little danger of making too deep a cut into the 
 hide or skin, that the work may be done more efficiently 
 than hitherto, and that the edge may be renewed with 
 great facility. For this purpose an edge is given to these 
 cylinder blades similar to that used on the ordinary cur- 
 rier's or beamsman's shaving knife, that is to say, the edge 
 is slightly bevelled, and in the bevelling a very thin feather 
 or ' burred ' cutting edge is formed by the thread or turn- 
 over of the metal. This thread or cutting edge may be 
 constantly renewed by simply reversing the movement of 
 the cylinder, and bringing the blades into contact with an 
 emery plate, file or other sharpener, throwing up the 
 
 * See Chap. xxxi. on Machinery Employed in Leather Manufacture for 
 more recent information. — Ed. Fifth Edition. 
 
316 LEATHER MANUFACTURE. 
 
 feather or thread, which is then adjusted by the ordinary 
 tool or ' steel.' " 
 
 The Duplex TTnhairing Machine has been practically 
 adopted by Mr. Carlaw for a considerable time, and has 
 proved to be a most satisfactory piece of mechanism. Mr. 
 Carlaw, who frequently operates the machine himself, 
 informs us that he can readily unhair and flesh in one 
 operation, two and a half dozen calf skins per hour, or one 
 in every two minutes, and the ease with which this is 
 accomplished is really surprising. On examining some pelts 
 after they had passed through the machine we were much 
 pleased with the perfect uniformity and regularity with 
 which the machine had done its work. A very useful 
 feature in this remarkable apparatus is that the pelts are 
 washed at the same time they are being unhaired and 
 fleshed, by a series of jets of water issuing from per- 
 forated horizontal tubes, which play upon both sides of 
 the skin. After passing through the machine the skins 
 are thrown into a tub of water until required for the next 
 operation. 
 
 Turing. — The 'pure — which is a lixivium of pigeons' 
 dung in water — is kept in large tubs, and in this the un- 
 haired skins are placed and allowed to remain, with fre- 
 quent turning over, until they acquire a certain texture, 
 by which the workman judges the operation to be com- 
 plete, when they are removed and submitted to the 
 operation of scudding. 
 
 Scudding. — The object of this operation is to remove a 
 film which remains upon the pelt after the hair has been 
 removed, and also to force out from the skin the salts of 
 lime formed by the action of the pure upon the lime 
 absorbed by the skins in the lime-pits. The " scud " is 
 removed by working the pelt upon the beam with the blunt 
 knife, and after scudding the pelts are thrown into a large 
 tub containing the bran drench. 
 
 Drenching. — The skins are allowed to remain in the 
 bran drench — which is kept in an active state of acetous 
 fermentation — until the workman judges that the desired 
 eifect is produced, which is determined by the appearance 
 
WHITE LEATHER. 317 
 
 and feel of the pelt under pressure of the fingers. When 
 the skins are first thrown into the drench, they sink to 
 the bottom of the vessel, but as fermentation progresses 
 (which is evidenced by a brisk evolution of carbonic acid 
 gas) the skins rise to the surface, and the liquid becomes 
 covered with a white froth or foam. After drenching the 
 pelts are handed over to the dresser, in whose hands they 
 undergo the subsequent operations which convert them 
 into tawed leather. 
 
 Alum Dressing. — A solution of alum and salt, consisting 
 of three parts of alum to four parts of salt, dissolved in 
 waters-is prepared and placed in large tubs, and in these 
 the skins are placed and subjected to its action for about 
 two weeks, or until the skins are properly " leathered," 
 which is ascertained by pressing folds of the skin between 
 the fingers, when, if the sharp bend of the skin assumes an 
 opaque white streak, and not transparent, the skin is 
 known to be properly tawed — not tanned, as some will 
 persistently call it. 
 
 Drying. — The alumed skins are next hung up in the 
 drying-room, or stove, as it is sometimes termed, until 
 quite dry, when they are called " crust goods," from their 
 exceeding hardness. 
 
 Seasoning. — The dried skins are next soaked in water 
 for a short time, to season them for the process of staking, 
 which is thus performed : — 
 
 Staking.— The skin is laid across the perch, and the 
 workman takes the stake, or " crutch " stake as some call 
 it, in his hand, and placing the cross-handle under his 
 right arm, holds the upright stock firmly in his hand, 
 while with the left hand he seizes a corner of the skin, 
 and forces the blade of the tool (which somewhat resembles 
 the blade of a blunt cheese knife) from above downward, 
 by which means he not only stretches the skin, but also 
 renders it exceedingly soft and pliant. 
 
 Shaving. — The skins are next shaved, either by hand or 
 by the shaving machine (Fig. 67), by which the flesh side 
 becomes uniformly levelled by reducing the substance of 
 the stouter parts. 
 
3 i8 LEATHER MANUFACTURE. 
 
 Egging. — The shaved sldns are now ready for the egg- 
 paste or emulsion, which, with the skins, is put into a re- 
 volving tumbler, and the machine kept in motion until 
 the skins have thoroughly absorbed the composition, when 
 they are withdrawn, stretched out, and conveyed to the 
 dyeing-room. 
 
 Dyeing. — The skins are first " mordanted " by being 
 put into a tank containing urine, after which they are 
 drained and folded lengthwise, flesh side inward. They 
 are next placed in a tray containing a hot solution of log- 
 wood. From this they are transferred to a second tray, 
 containing a solution of sulphate of iron (copperas), which, 
 with the former treatment, stains the grain of a deep blue- 
 black. The dyed skins are now laid over a horse or 
 tressel to drain, after which they are hung in the drying- 
 room, where they are allowed to dry gradually. "When 
 dry they are again seasoned with water, to prepare them 
 for grounding, which operation is performed by scraping 
 the flesh side with the " moon-knife," a tool somewhat 
 resembling the round knife, but, being furnished with a 
 horizontal handle at the lower part of the aperture, this 
 tool is held in one hand, whereas the round knife is held 
 bv both hands. The workman holds a corner of the skin 
 depending from the perch with his left hand while 
 scraping the skin with the moon-knife. After grounding 
 the skins are laid flat on a bench or table, grain or coloured 
 side up, and are then ironed with hot irons, much in the 
 same way as linen. The skins are then sorted into sizes 
 for market. 
 
 White Sheep Leather. — The unwooled skins, as they 
 are received from the fellmonger, are first steeped in the 
 lime-pits to swell, soften, and cleanse them, being repeatedly 
 drawn and allowed to drain upon inclined tables, which 
 operations are continued for about three weeks. The skins 
 are next rubbed on the grain side with a whetstone fixed 
 into a wooden case with two handles, in order to free them 
 from any adhering filaments of wool. They are then 
 ready for the bran steep, which is made by mixing 40 lbs. 
 of wheat bran in 20 gallons of water ; in a short time 
 
WHITE LEATHER. 3 r9 
 
 fermentation supervenes, when acetic and other acids are 
 liberated, which convert the lime within the pores of the 
 skin into soluble salts, which subsequent working on the 
 beam, alternated by washings, removes. It is usual to 
 add some old bran liquor to the bran steep, to promote 
 acetous fermentation. During the time that the slcins are 
 in the steep they require to be frequently turned over, 
 with careful watching, otherwise the pelts will suffer 
 considerably from the action of the vegetable acids present 
 in the fermenting liquor. In about two days in summer, 
 and eight days in winter, the skins are said to be raised. 
 At the-end of from two to three weeks they are ready for 
 the next operation, termed aluming or alum dressing. 
 
 Aluming'. — The alum bath for a hundred skins is com- 
 posed of from 14 to 18 lbs. of alum and from 2^ to 3 lbs. 
 of common salt, which are placed in a copper with 
 12 gallons of water. When the mixture begins to boil, 
 three gallons of it are passed through a colander into a tub, 
 and into this twenty- six skins are introduced and worked 
 one after another. After draining they are put together in 
 the bath, and left therein for about ten minutes to further 
 absorb the liquor. They are now ready for the next 
 operation, which consists in treating them with a paste 
 composed of flour and yolk of egg. 
 
 The Paste. — This is formed by mixing (for a hundred 
 skins) about 14 lbs. of wheat flour with the yolks of fifty 
 eggs in the following way : the alum bath through which 
 the skins have been passed is first warmed, when the flour 
 is sprinkled into it and well stirred in ; the paste is well 
 kneaded by additions of the solution, and it is then passed 
 through a colander, by which it becomes smooth and clear. 
 The yolks of eggs are next added, and the whole thoroughly 
 well mixed by careful and vigorous stirring. The skins 
 are first worked one after another in this paste, and then 
 the whole number are placed together in the mixture, in 
 which they are allowed to remain for a day. They are 
 afterwards removed one by one, stretched upon poles, and 
 left in the drying loft for a week or ten days, according to 
 the season and the thickness of the skins. 
 
320 LEATHER MANUFACTURE. 
 
 The effects of the paste are that the skins become 
 whitened, softened, and protected from the hardening 
 influence of the atmosphere, to which the oily matter of 
 the eggs largely contributes. But for this treatment the 
 skins would be unable to bear the severe processes of 
 stretching or staking to which they are afterwards sub- 
 jected to render them soft and pliant. 
 
 Staking. — Before being worked on the stake (Fig. 52) 
 the skins are steeped for a short time in clean water ; the 
 workman then takes a skin and works it to and fro, flesh 
 side downwards, over the semi- circular knife or blade of 
 the stake with considerable force, by which it becomes 
 stretched in length in the proportion of five to three. By 
 this operation the whiteness of the skin is greatly im- 
 proved, while it acquires the utmost degree of suppleness 
 which it is susceptible of attaining. The skins are after- 
 wards stretched by hooks and strings and hung up to dry. 
 When dry they are worked on the stretching-iron, or they 
 are polished with pumice-stone. Sometimes a yellowish 
 tint is given to the skins by a mixture of whiting and 
 yellow ochre in a moist state rubbed over the grain. After 
 pumicing, the skins are smoothed with a hot iron, in the 
 same way that linen is ironed, b}^ which the grain assumes 
 a brilliant and glossy surface. 
 
 Large sheep skins are also extensively converted into 
 white leather by the process of tawing with alum and 
 salt, for aprons used by workmen employed in iron works, 
 which are found to resist the action of heat better than 
 tanned leather. Sometimes also these skins are partially 
 tanned with bark, and afterwards treated with alum and 
 salt, for making leggings, gaiters, coarse gloves, &c, used 
 by farmers and agricultural labourers. This latter trade 
 is now chiefly carried on in the provinces. 
 
 Splitting Sheep Skins, — Amongst the many ingenious 
 contrivances employed in the manufacture of the different 
 kinds of leather, none probably is so remarkable as the 
 machine which is capable of cutting or splitting an 
 unhaired skin into two or even three sections, without 
 forming holes in either section. Although there are 
 
WHITE LEATHER. 321 
 
 several modifications of the splitting machine— originally 
 adopted, we believe, by the eminent firm of Bevington 
 and Sons — a description of their now famous machine will 
 doubtless suffice to indicate the principle upon which, skins 
 are subdivided by machinery. The following details of 
 this important machine are taken from an interesting 
 work entitled Days at the Factories : — 
 
 " Two rollers (Fig. 53) ranged horizontally in a frame 
 are made to rotate in opposite directions, the vacancy 
 between them being only just sufficient to admit a soft 
 wetted sheep skin or pelt. The rotation of the rollers causes . 
 the skyi to be drawn slowly between these ; but it cannot 
 do so without encountering the blade of a very sharp knife 
 which has a reciprocating horizontal motion, in such a 
 position as to cut the skin into two thicknesses as it 
 passes the knife, one half passing over and the other 
 under the blade, a most ingenious contrivance for yielding 
 to any inequalities which may occur in the skin. One of 
 the rollers is made in several pieces, so adjusted that in 
 passing over any thickened portions of the skin the 
 common aperture between the rollers is widened at that 
 part. It is one of the peculiarities in the construction of 
 the machine that one of the semi-thicknesses or sections 
 of the skin must be equable and level in every part, while 
 the irregularities which might have existed in the 
 original skin will be thrown into the section. Either 
 section, the ' grain ' side or the ' flesh ' side, may have 
 this equable thickness given to it according to the mode 
 in which the skin is adjusted on the rollers ; and the two 
 portions may have various ratios given to their thickness 
 according to the position of the vibrating knife opposite 
 the opening between the rollers. A sheep skin of the 
 usual size occupies about two minutes in splitting, during 
 which time the knife makes from 2,000 to 3,000 vibratory 
 motions to and fro, cutting a minute portion of the skin 
 at each movement." 
 
 A representation of skin-splitting is shown in the sketch 
 (Fig. 53). These machines are now made to split skins 
 into three equal sections or slices, the grain being used 
 
 Y 
 
322 LEATHER MANUFACTURE. 
 
 for skiver, the middle portion for parchment, and the flesh 
 
 1'is. 53. 
 
 side, being of unequal surface, and therefore unsuited for 
 conversion into leather, being used for glue-making. The 
 
 Fig. 54. 
 
 American Union Splitting Machine, used to some extent 
 for splitting tanned leather, is shown in Fig. 54.* 
 
 * See also Chap. xxxi. p. 412. — Ed. Fifth Edition. 
 
CHAPTER XXVII. 
 
 CHROME LEATHER MANUFACTURE. 
 
 Preliminary Operations. — Liming and Unhairing. — Fleshing. — Puring 
 or De-liming. — Scudding. — Chroming Operations. — Striking-out and 
 Shaving. — Dyeing Chrome Leather. — Fat-Liquoring. — Dyeing 
 Black. — Putting or Striking Out. — Oiling and Drying. — Staking or 
 Softening. — Seasoning. — Glazing. 
 
 In the development of what is known as the chrome 
 process, the past few years have witnessed a complete 
 revolution in leather-making, and one which has had 
 far-reaching consequences upon the producing and con- 
 suming side of leather manufacture in glace kid, box and 
 willow calf, sides, belting and harness, &c. We have 
 had an absolute departure from the older forms of tanned 
 leathers, and it is only fair to describe the success of 
 chrome leathers as the outcome of American perseverance 
 and ingenuity in exploiting technical chemistry for the 
 purposes of commercial industry. 
 
 Only a few years ago the man who ventured to express 
 his belief that " chemicals " would take the place of oak 
 bark for leather-making was looked upon as a dreamer ; 
 now the French tanner of bark upper leather is largely 
 displaced, America has captured the cream of the world's 
 glace leather trade, and British and Continental manu- 
 facturers have taken up chrome leather-making with a 
 fair amount of success. 
 
 It may be permissible here to briefly summarise the 
 history and technique of the process, for it is certain 
 much of the business of the leather manufacturer of the 
 
324 LEATHER MANUFACTURE. 
 
 future will depend upon the successful catering for this 
 particular branch of the industry. 
 
 As far back as 1858, the late Professor Knapp brought 
 out a chrome process, but it created little notice in the 
 industrial world, and was regarded as of only chemical 
 interest. In 1879, Heinzerling patented a form of chrome 
 leather ; this, again, attracted little attention, and it was 
 left to the ingenuity of August Schultz, of New York, to 
 bring out an idea commercially valuable. His patent 
 was dated January 8, 1884 ; and although it has now 
 expired, it has been the subject of endless litigation in 
 America, which always ended in favour of the patentee. 
 
 The Original Schultz Patent. 
 
 Briefly put, the principle of the chrome tannage de- 
 pends upon the formation of chromic oxide in the skin, 
 this being brought about by the reduction of chromic 
 acid with suitable agents. As a good deal of the lighter 
 class of chrome leather is still made in much the same 
 way as by Schultz's method, it will be advantageous to 
 give here his original specification. 
 
 "This invention relates to a new process for tawing 
 hides or skins, said process consisting in subjecting said 
 hides or skins to the action of compounds of metallic 
 salts — such as bichromate of potash — and then treating 
 the same with hyposulphite of soda, by which term is 
 understood that salt which is more recently sometimes 
 called ' thiosulphate of soda ' (Na 2 S 2 3 ). 
 
 "In carrying out my process I unhair the raw hides 
 and prepare them in the same manner in which they are 
 made ' ready ' for tanning. If the hides have not been 
 pickled, I subject them to the action of a solution of 
 bichromate of potash in the presence of an acid — such as 
 hydrochloric acid — or, if the hides have been pickled 
 they may be treated in a solution of bichromate of potash 
 in water without the addition of an acid. 
 
 "In this solution the hides are left for a shorter or 
 
CHROME LEATHER MANUFACTURE. 325 
 
 longer time, according to their thickness and to the 
 strength of the solution employed. A skiver or the face 
 of a sheep skin can be done in a strong solution, as above 
 described, in about fifteen minutes, while a full skin 
 ' roan ' would require in the same solution about one 
 hour. I call the solution 'weak' if it contains 5 per 
 cent, or less of the weight of skins of bichromate of 
 potash, and I call the solution ' strong ' if it contains 
 more than 5 per cent, of bichromate of potash. It is 
 not material, however, how strong the solution is. 
 
 " The skins are completed if small pieces cut from 
 the thickest parts of said skin show that the solution 
 has entirely penetrated. The skins are then ready to 
 be taken out, and after the adhering liquor has run off, 
 the skins are introduced into the second solution, which 
 consists of hyposulphite of soda dissolved in water, and 
 adding an acid, such as hydrochloric acid. The solution 
 may be strong or weak of hyposulphite, and the quantity 
 of acid used at first may be less than requisite to split up 
 the entire quantity of hyposulphite, and more acid may 
 be added if the skins show that more is required, which 
 is indicated by the colour of the skins. When they 
 are done they show a whitish, bluish, or greenish colour, 
 according to the time they are kept in the hyposulphite 
 solution. 
 
 "A skiver which first has been exposed to the action 
 of the bichromate for fifteen minutes will be ready by 
 remaining in the hyposulphite solution about twenty 
 minutes. For thicker skins a proportionately longer 
 time is required. For some skins — such as calf or steers' 
 skins — it is desirable that the same, after having been 
 withdrawn from the second or hyposulphite solution, shall 
 be returned to the bichromate solution, which imparts to 
 them a brownish colour, and leaves them in a favourable 
 condition to be coloured black. The colouring can be 
 clone after the skins leave the hyposulphite solution, and 
 after they have been exposed for the second time to the 
 bichromate solution. The leather coming from the 
 hyposulphite solution is especially adapted for light or 
 
326 LEATHER MANUFACTURE. 
 
 dark colours, and by proper dyeing methods better and 
 brighter colours can be produced than on leather done by 
 tannin. After the leather is treated in the manner above 
 indicated, it may be coloured, soaped, and greased in the 
 usual way. 
 
 " Leather can also be made by reversing the operation 
 and first soaking the hides in a solution of hyposulphite 
 of soda and then exposing them to the action of the 
 bichromate solution. By using the solutions indicated 
 at a heat of about 80° Fahr., the process will be done in 
 a shorter time than if the solutions are used cold. 
 
 " By my process the gelatine contained in the hides is 
 rendered insoluble by means not injurious to the leather. 
 If leather made by tannin is put in a strong soda solution, 
 the tannin is extracted, and a dark brown liquor is formed. 
 If leather made by my process is put in a strong soda 
 solution, the liquor obtained shows only a little milky 
 colour. 
 
 " Leather made by my process is very strong, soft, 
 elastic, and my process is applicable to hides or skins 
 of every description." 
 
 It is obvious that many improvements in the manipula- 
 tion of the above process have been introduced since 
 it was brought out. As a matter of fact, however, the 
 main principle of the impregnation of the skin with 
 chromic acid remains much the same, and excellence is 
 obtained by a variety of small points in the subsequent 
 mechanical manipulations, mainly by the employment 
 of ingenious machinery and suitable materials. Theo- 
 retically, chrome leather is easy to make, but in practice 
 it is very difficult to attain any great amount of com- 
 mercial success without a large expenditure, enterprise, 
 and technical knowledge. 
 
 Chrome leather may be made by two methods, which 
 are technically known as the " one-bath " and the " two- 
 bath " methods. Opinions differ as to the results obtained 
 by each, but, generally speaking, the heavier leathers, 
 such as harness, belting, picker, and calf leathers, are 
 obtained by the use of the one-bath method, which is 
 
CHROME LEATHER MANUFACTURE. 327 
 
 very simple in its application, and depends upon the use 
 of a dilute solution of a basic chromic salt, the goods 
 being subjected to its action in gradually increasing 
 strengths until struck through. This method will be 
 dealt with later on. 
 
 Light goods, however, such as glazed goat and sheep 
 skins, are generally treated by the two-bath process, and 
 the following summary may be taken as fairly repre- 
 sentative of the method now in vogue : — 
 
 Chrome or Glac£ Goat Skins. 
 
 The immense demand for goat skins has led to a regular 
 advance in the price of the raw material, and it has been 
 humorously said that where a goat is wandering, there 
 waits an American for him to die. It will, therefore, be 
 gathered that the demand for skins is very great, so much 
 so that there is now no corner of the world which has not 
 been drawn upon for supplies. The enhanced value of the 
 pelt, too, has led to increased attention being devoted to 
 its primary preparation for storage and transit, and skins 
 are now carefully treated with various compounds for more 
 complete preservation. A large business has sprung up, 
 for instance, with Australia and JSTew Zealand in the 
 export of what are known as pickled skins. These are 
 put through the preparing process of soaking, liming, and 
 unhairing, fleshing, scudding, &c, when they are given a 
 bath of weak sulphuric acid solution. In this they rapidly 
 swell ; salt is then added, and the skins become reduced, 
 and are in reality pickled with a sort of glauber salt. 
 The result is fairly good, but the recent Society of Arts 
 committee, appointed to deal with the deterioration of 
 bookbinding leather, has pointed out that the action of 
 the acid often tends to a serious weakening of the animal 
 fibre, and that the resultant leather is sometimes not to 
 be depended upon. The result has been that other pre- 
 servative agents have been employed, such as formic 
 and acetic acids, and it is claimed their use shows a 
 
328 LEATHER MANUFACTURE. 
 
 distinct improvement upon the ordinary pickling or 
 salting methods. 
 
 Various proprietary articles have also been put on 
 the market for the purpose, and one especially has given 
 remarkably good results, viz. Atlas Preservative " S," sold 
 by the Atlas Preservative Company, Windmill Lane 
 Wharf, Deptford, London, S.E. This, it is claimed, per- 
 fectly preserves skins and hides in a fresh condition, and 
 no difference can be detected in the finished leather when 
 compared with that made from fresh-slaughtered goods. 
 This preservative may be used with a little salt in such a 
 manner as to keep the skins in a damp and moist condi- 
 tion, or painted in a weak solution on the flesh side, and 
 the skins subsequently dried out and baled for transport. 
 As it is usual to find about ten per cent, of badly damaged 
 skins in certain grades of goat skins, the fact that a method 
 has been evolved to stop this economic waste cannot be 
 too widely known. Experts have reported very favour- 
 ably on the Atlas Preservative, and good leather has 
 been made from skins treated in all parts of the world. 
 
 Preliminary Operations. — A good deal, of course, 
 depends upon the sort and condition of the various 
 goat skins, as regards the first stages of glace goat manu- 
 iacture. Skins, as before mentioned, are of world-wide 
 origin, and the pelts from Southern Europe, South 
 America, China, and India all show various charac- 
 teristics which necessitate differences in treatment. The 
 most esteemed skins perhaps are what are known as 
 Patna skins, coming from India. These, generally 
 speaking, are of good quality and fibre, and produce a 
 fine and close grain, which is a sine, qua non in kid 
 manufacture. Taking this class, then, as representative, 
 the procedure is as follows : The skins are first soaked 
 in plenty of clean water; the time varies according to 
 the condition of the skins, but about two or three days 
 should be sufficient to bring them back to a good soft 
 condition. This is greatly facilitated by the addition of 
 a little borax or soda to the soak liquors, about one pound 
 of borax per three hundred gallons being considered 
 
CHROME LEATHER MANUFACTURE. 329 
 
 sufficient for the purpose. Sulphide of sodium is also 
 used for the same purpose, and has a decided effect 
 on softening the hard nature of the skins and getting 
 them into condition for liming. Care should, of course, 
 be taken that putrefaction does not set in, and this may 
 be guarded against by changing the first water after 
 about twenty-four hours, and after drawing the skins, 
 to put them into the second soak treated with some 
 disinfectant. 
 
 If the skins are very hard and dirty, a "breaking 
 over " between the changes of water is beneficial. This 
 breaking over is done in small tanneries by well stretching 
 and working the wet skin with a blunt tanner's knife over 
 the half-round beam. In the large chrome works, how- 
 ever, this mechanical softening is at times done by the use 
 of the fulling stocks (see Fig. 6). The pounding motion of 
 this machine is very effective where short-haired skins 
 are under manipulation, and from twenty minutes to 
 half an hour is usually ample time to break down the 
 most obstinate pelt. Some classes of skins may be 
 softened effectually in a drum tumbler ; but however 
 softened, the general theory should be to bring the pelts 
 back as far as possible to their original soft and pliant 
 condition. 
 
 Liming and TTnhairing. — In the manufacture of glace 
 goat, lime and arsenic sulphide are the materials gener- 
 ally favoured for depilation. Experience has shown that 
 the action of lime loosens the hair, distends the fibres of 
 the skin, assists to neutralize the natural fat, and so far acts 
 upon other constituents not necessary to leather-making 
 that they may be mechanically worked out later. In 
 practice it is common to add about 5 lbs. of "red 
 arsenic " to about 100 lbs. of lime slacked in a large tub. 
 The lime should be thoroughly slaked with enough water 
 to moisten it, and the arsenic added and mixed thoroughly 
 with the lime, and the whole mass well stirred. A minor 
 objection is that sulphuretted hydrogen is evolved during 
 the process, so that it should be carried out in the open 
 air, if possible. The arsenic helps to shorten the time of 
 
330 LEATHER MANUFACTURE. 
 
 the depilating process, whilst it also greatly assists in 
 producing leather of a supple texture and a smooth 
 grain. 
 
 When the above quantities of lime and arsenic are 
 dissolved the solution is thrown into the pit with sufficient 
 water, care being taken that no undissolved particles or 
 stones find their way in. No definite rule can be laid 
 down, but the quantities stated are sufficient to unhair 
 from five hundred to six hundred skins. After the skins 
 have laid in the solution for a day or so they are hauled 
 up and laid up to drain, the solution being well plunged 
 up before the skins are re-entered. It may be also 
 necessary to strengthen it by the addition of a little more 
 lime and arsenic after a day or two, but a good deal 
 depends upon whether old or new liquors were used at 
 the start ; generally speaking, it is inadvisable to use 
 much lime toward the end of the process, as it has a 
 tendency to produce a coarse grain on the finished leather. 
 In some factories it is considered safe to start with a liquor 
 showing about 3° Twaddle, and finishing up with one at 
 about 5° or 6°. The time taken for depilation varies, but 
 may be approximately put at from ten to fourteen days, a 
 good deal depending upon the condition of the skins, the 
 temperature of the solution, and the handling the goods 
 receive. Some manufacturers profess to have had good 
 results in the use of sulphide of sodium for unhairing. 
 This has the disadvantage of practically destroying the 
 hair, and as this in some classes of goat skins is valuable, 
 the sulphide is not much favoured for that reason. Various 
 methods are followed out where sulphide is used ; it may 
 be painted on the flesh side of the skins, or the skins 
 may be thrown into a weak solution ; or, again, it may be 
 used in conjunction with lime as in the case of arsenic 
 sulphide. However, as practically all the successful 
 chrome goat manufacturers use the arsenic limes, it is 
 not perhaps advisable to take up valuable space by deal- 
 ing further with the sulphide of sodium methods. If 
 sulphide of sodium is used in conjunction with lime, 
 about a third of the former is sufficient ; the goods are 
 
CHROME LEATHER MANUFACTURE. 331 
 
 worked much as in the case of lime, and the skins are 
 ready for unhairing in about six to ten days, according to 
 substance, &c. When the skins have had enough lime they 
 are usually washed in water to cleanse them as far as possible, 
 and if the shanks, &c, have not been removed before, they 
 are trimmed away when the skins are ready for unhairing. 
 
 The unhairing, being a very simple operation, is often 
 done by hand on the half-round tanner's beam with a 
 blunt knife; of late years, however, this operation has 
 been done by machine. The only drawback to the use 
 of the machine for unhairing is that the holey and de- 
 fectiva skins are rather harshly treated, and if great care 
 is not used a skin is often so torn by the action of the 
 spiral knives that it is practically worthless. 
 
 Fleshing. — In nearly all large chrome leather works 
 goat skins are fleshed by machine. The operation is, 
 however, comparatively simple, and in countries where 
 there is an abundant supply of cheap labour, it is easy to 
 train men to flesh goat skins in the old-fashioned way with 
 the ordinary tanner's knife. Goat skins, as a rule, are not 
 very fleshy, and most of the loose tissue can be removed 
 by the " brushing " or scraping edge. The machine 
 usually employed for fleshing is illustrated at Fig. 74, 
 the skin being spread flesh outwards on a special rubber 
 roller, and subjected to the action of a cylinder fitted 
 with spiral knives. A modified form of the machine, 
 shown as Fig. 64, is also often used for fleshing. The 
 work done by the machine answers on the whole very 
 well, and is cheaper in Europe and America than the 
 hand process could be. Many small glazed kid manu- 
 facturers use the same machines for unhairing, fleshing, 
 and scudding, using different cylinders for the various 
 purposes. As the output of chrome kid, however, has 
 to be very large to ensure a profit, this is not to be 
 recommended, except for exceptional cases, or for the 
 experimental stage of glazed kid manufacture. In 
 machine fleshing great attention should be paid to the 
 cutting cylinder and to the rubber bolster, otherwise the 
 work will be defective, and a good deal of damage ensue 
 
332 LEATHER MANUFACTURE. 
 
 to the skins under operation. In no case should fleshing 
 be entrusted to any but a most intelligent man, who 
 should be encouraged by good wages to become a 
 thorough master of the operation. 
 
 Puring or De-liming. — To ensure the production of a 
 good tough and elastic leather with a fine " break " and 
 grain, it is necessary to pay special attention to this 
 process. If lime be present in the skins when they go to 
 the chrome bath, it is turned into sulphate of lime, and 
 the leather is hard and often brittle. After fleshing, the 
 skins are trimmed where necessary, and well washed in 
 plenty of soft water to remove as much lime as possible, 
 and, after draining, are ready for the puring operation. 
 All sorts of de-liming agents have been tried, such as 
 sulphuric and lactic acids, &c, but experience has shown 
 that in the majority of cases the old and disagreeable 
 excrement pure gives the best results. Some manu- 
 facturers, however, claim to have used " Erodin," intro- 
 duced by Mr. J. T. Wood, of Nottingham, and Drs. Popp 
 and Becker, of Germany, with good results. This bate, 
 or pure, depends for its effect upon the bacteriological 
 action, and was invented after much patient experiment- 
 ing had enabled the inventors to isolate the active 
 organism, and to put a culture and a cheap medium for 
 its propagation before the trade. 
 
 Space, however, will not admit of enlarging upon the 
 various de-liming agents which have been tried, and as 
 dog-dung is by many still regarded as the best material 
 for glace goat, we will devote our limited space to a con- 
 sideration of its use. In puring it is necessary to 
 remove the dissolved gelatinous substance, the hair 
 sheaths, fat glands, &c, and the lime soap produced 
 by the action of the lime on the natural fat of the skin. 
 
 For the heavier kinds of hides and skins, hen and 
 pigeon dung is used for bateing, but in England dog- 
 dung is almost exclusively employed for the process in 
 goat-leather manufacture. It is usually obtained from 
 dog-kennels, and as it varies in strength and charac- 
 teristics, it is difficult to give any definite directions for 
 
CHROME LEATHER MANUFACTURE. 333 
 
 its use. As dog-dung rapidly ferments it should not be 
 exposed much to the air. In many works it is mixed 
 with a little water to a paste, and kept in this way, and 
 in no case should the dung be used until it has been 
 allowed to ferment for six or seven days. In practice a 
 few pails of the semi-liquid dung is added to water at a 
 temperature of about 90° Fahr., the dung being first 
 strained through a coarse bag to remove bits of bone, 
 gravel, and other sediment. The skins soon begin to 
 " fall " in the solution, or lose their plumpness, and are 
 considered to be sufficiently pured when the grain 
 retains-the impression of the thumb or fingers. In large 
 works this puring operation is performed in paddles, 
 the strength of the concoction and the time the skins 
 are allowed to remain in it varying according to the 
 system followed out or the ideas of the pureman, who, 
 by the way, should be an experienced and skilled 
 workman. 
 
 Scudding. — After the skins have been pured, drenched, 
 or both, as the case may be, they are then carefully 
 worked over on the grain side to remove the lime-soap, 
 pigment, fat, short hairs, and other matter. This is also 
 a very necessary operation, as if much " scud " is left in 
 the skins, the leather on finishing refuses to glaze pro- 
 perly, whilst any hairs remaining would quite spoil the 
 look of the finished article. 
 
 In some places the scudding is still done on the 
 tanner's beam with the half-round slate " knife," the 
 workman thoroughly extending and working out the soft 
 and flaccid skin in every direction. It is usual now, 
 however, to do this operation by a machine similar to 
 that described in fleshing, the skin being subjected to 
 the action of a cylinder into which slate tools are let 
 in, the bolster being of stout rubber. The work is done 
 fairly well and very cheaply ; but it is a good rule to 
 have the skins examined and to rectify any faults by hand 
 on the beam. Some of the short-haired goat skins, such 
 as Patnas, often scud very badly, and want a good deal 
 of attention to get a clean and fine grain. Others, again, 
 
334 LEATHER MANUFACTURE. 
 
 such as Chinese skins, scud well and make good clean 
 leather with comparatively little trouble. 
 
 Too much attention can hardly be paid to this branch 
 of glace leather manufacture, and attempts at economy 
 here may turn out disastrously later on if the pelts are 
 not freed from impurities and short hair. It is even 
 necessary, in extreme cases, to lightly shave the grain 
 where the liming or puring operations have not been 
 carried out thoroughly. After scudding, the skins are 
 either left for a few hours to drain, or, if necessary, are 
 washed in plenty of clean water. Some manufacturers 
 wash in the paddle in a dilute lactic acid solution, and 
 then in a weak borax solution, 1 lb. of the latter to about 
 150 to 200 gallons of water being sufficient. 
 
 Chroming Operations. — No two glace goat makers 
 follow quite the same procedure, and whilst some see an 
 advantage in giving the skins a pickle of acid and salt 
 before proceeding to the actual chrome tanning, others 
 dispense with this process as unnecessary. If the former 
 process is clone, however, one American authority says 
 that 10 lbs. of salt for each 100 lbs. of drained pelt, dis- 
 solved in 15 gallons of water, is sufficient. The skins are 
 run in a drum with this solution for about fifteen 
 minutes, and the acid given. This is prepared by mixing 
 2 lbs. of muriatic acid (hydrochloric) in a pail of boiling 
 water and cooled with two pails of cold water. This 
 is added to the skins in the drum, which are run for 
 another fifteen minutes, when the skins are ready for the 
 chrome bath. 
 
 The saturation of the lighter pelts, such as calf and 
 goat, with the chromic acid is invariably carried out in 
 the paddle or drum, and in all large works separate ones 
 are used for tanning, reducing, washing, &c. Care should 
 be taken to see that the driving arrangements are always 
 in good order, as a breakdown often involves serious 
 trouble and loss. 
 
 The chrome bath is prepared by dissolving bichromate 
 of potash in boiling water which is acidified with 
 hydrochloric acid, and this is added to the goods 
 
CHROME LEATHER MANUFACTURE. 335 
 
 whilst they are running in a suitable quantity of water. 
 The quantity of bichromate of potash is calculated on 
 the weight of the wet drained skins, and varies from 
 4 to 6 lbs. per cent. In practice, about 15 gallons 
 of water to 100 lbs. of skins is recommended. The 
 amount of bichromate of potash is not very material, 
 but from 5 to 6 lbs. per cent, of wet pelt is a safe margin. 
 One method is to dissolve 6 lbs. of bichromate of potash 
 in 20 gallons of water, to which is carefully added 3 lbs. 
 of acid. Some authorities also advise the addition of a 
 few pounds of salt to the solution, but of this the writer 
 has had. no experience. In practice it is advisable to 
 dissolve the bichromate of potash in a suitable quantity 
 of hot water, and add the solution to the goods whilst in 
 motion in the drum or paddle, the requisite amount of 
 acid being added in successive stages. 
 
 The skins are padded in the acidified liquor until they 
 assume a yellow colour throughout, the process being 
 finished when a cut in the thickest part of the skin shows 
 complete penetration. When completely struck through, 
 the skins are taken out of the acid solution, horsed up 
 carefully, care being taken to avoid light and wrinkles, 
 and the excess of liquor struck out by machine. The 
 next process, technically called " reducing," is the re- 
 duction of the chromic acid. In many works the skins 
 are first dipped one by one into a weak solution composed 
 of about 4 or 5 lbs. of hyposulphite of soda dissolved in 
 15 gallons of water; this is sufficient for 100 lbs. of wet 
 pelt. This dipping process is assumed to somewhat " set " 
 the grain side of the leather, and so prevent the tendency 
 of wrinkling or coarseness caused by the sharp action of 
 the reducing bath. This latter is usually done in paddles, 
 10 lbs. of hyposulphite of soda being dissolved in 20 
 gallons of water and added to the proper amount of 
 water in the paddle. Five per cent, of muriatic acid, 
 calculated on the wet weight of the skins, is then added, 
 and the skins paddled in this until they lose their original 
 yellow colour and assume a bluish-green tint through- 
 out. It is a good plan in practice to so arrange the 
 
236 LEATHER MANUFACTURE. 
 
 work that the chroming begins in the morning and is 
 completed in the evening. It is of the greatest im- 
 portance that the reduction should be complete, as no 
 amount of work in the subsequent stages will ever make 
 a first-rate article. It is also an advantage if the skins 
 are sorted into various substances before chroming, other- 
 wise the penetration is uneven throughout the pack, and 
 the heavy skins may be under-tanned. It might also be 
 mentioned that the reduction should be done in a well- 
 ventilated room, as the fumes given off during the 
 process are both disagreeable and detrimental to the 
 health of the workman. When the skins are perfectly 
 chromed throughout they are taken out of the paddle, 
 and are then given a prolonged washing in a weak borax 
 solution, followed by plenty of water. This will neutra- 
 lise any free acid remaining, and should be continued 
 until no reaction is shown by the leather when tested with 
 litmus paper. 
 
 Striking-out and Shaving. — The skins are next well 
 struck out by machine, and passed on to the shaving 
 machine. In the case of goat skins it is often only 
 necessary to level the necks and backs of the skins, 
 although if of stout substance they will require reducing 
 all over. This process must be done with judgment and 
 by careful operators, if damage to the leather is to be 
 avoided. The fact, too, that there is a certain element 
 of danger in working the shaving machine should 
 make the selection of operators worthy of more than 
 ordinary consideration. The cost of machine shaving is 
 not great, and varies from about a penny to threepence 
 per dozen. 
 
 Dyeing Chrome Leather. — If the skins are to be 
 divided into black and coloured work, the sorting must 
 be done at this stage ; only the finest and most perfect 
 grain skins are suitable for colouring fancy shades, so 
 that those which are marked, imperfect on the grain, or 
 greasy, should be put for black work. At the same 
 time it must be remembered that the quality of the 
 black skins is obviously deteriorated by sorting the 
 
CHROME LEATHER MANUFACTURE. 337 
 
 best skins out, so that a good deal of judgment is 
 required. 
 
 Dealing with the black skins, the first operation is to 
 mordant them for dyeing. This is technically termed 
 " blue-backing," as it has the effect of colouring the flesh 
 side of the skins a sort of bluish purple. The usual method 
 is to immerse the skin in a solution of warm logwood for 
 about half an hour, using the paddle or tumbler for the 
 purpose. Hemolin is also used for the same purpose, but 
 it is said the skins lose a slight fullness imparted to them 
 by the more astringent logwood. An American authority 
 says the following method of dyeing black produces a 
 very satisfactory result. The skins are drummed in a 
 liquor made up of about 4 ozs. of liquid sumac extract in 
 5 gallons of warm water, this being the quantity required 
 for about a dozen skins. The skins are then dyed with a 
 purple aniline, about 3 ozs. being sufficient for a dozen 
 skins. The skins are then passed through logwood or 
 hemolin liquor, and then through the iron striker, and 
 finished off with a bath of aniline black at a temperature 
 of about 130° Fahr. Nigrosine, methyl violet, and 
 other anilines are also used for blue-backing, but in 
 many cases glace leather manufacturers prefer to depend 
 mainly upon the use of the logwood solution, assisted by 
 hemolin, &c, which they consider give the best results 
 generally. 
 
 Fat-Liquoring. — When the skins are blue-backed 
 they are then ready for the next operation, termed " fat- 
 liquoring." This is necessary for the thorough lubrica- 
 tion of the fibres, and to produce a supple and tough 
 leather. 
 
 Experience has shown that the most convenient time 
 for the process is after the logwood mordanting bath, 
 although the process is sometimes done after the final 
 dyeing. Broadly speaking, the fat-liquor is simply an 
 emulsion in water of some oily or fatty material, or 
 materials. Most leather manufacturers have their own 
 special mixture. Neatsfoot oil, egg yolk, olive and 
 castor oils, special soaps, also sod oil and degras, are aU 
 
 z 
 
338 LEATHER MANUFACTURE. 
 
 used, but the first two named materials are perhaps the 
 best for kid leather, which has to bear a high polish and 
 a perfectly clear surface. Turkey red oil has also been 
 recommended for the purpose. Professor H. R. Procter 
 states that Turkey red oil (which is sulphated castor oil) 
 makes a convenient fat-liquor mixed with, warm water 
 without soap, and has been advocated where delicate 
 colours are to be dyed after fat-liquoring, although, it 
 is said to tend toward making the leather tender and 
 hard. 
 
 Fat-liquors should be as nearly neutral as possible, 
 although if any acid has been left in the skins a neutral 
 fat-liquor will cause a deposit of gummy matter on the 
 grain almost impossible to get rid of. Procter gives 1^ 
 per cent, of castor oil soap and f per cent, of castor 
 or olive oil on the wet weight of the pelt as being 
 serviceable. Another fat-liquor which is claimed by 
 an American writer to give great softness to the skins 
 is made as follows : 20 lbs. of soft soap and 40 lbs. of 
 sod oil is thoroughly emulsified in 50 gallons of water. 
 The soap should first be boiled in a few gallons of water, 
 and the oil added, and enough water then added to make 
 up the 50 gallons. About 2 gallons of this fat-liquor per 
 dozen is sufficient, and the liquor should be used in the 
 drum at a temperature of 130° to 160° Fahr. 
 
 For fine glazed kid the writer has always obtained 
 good results with suitable soap, neatsfoot oil, and egg 
 yolk for the fat-liquor, which is safe and easy to prepare. 
 Fifty gallons of this may be prepared by cutting up 
 10 lbs. of good soap and boiling in 50 gallons of water, 
 adding 3 or 4 gallons of best neatsfoot oil by instalments 
 until thorough emulsification takes place. It is con- 
 venient in practice to use only a part of the 50 gallons 
 for emulsifying, and to add the remainder cold, or nearly 
 so, to bring down the temperature to about 90° Fahr. 
 before adding the egg yolk ; otherwise the latter will be- 
 come more or less insoluble. Two or three gallons of this 
 fat-liquor per dozen is sufficient, although it is obvious a 
 good deal will depend upon the condition and size of the 
 
CHROME LEATHER MANUFACTURE. 339 
 
 skins. If any trouble is found in emulsifying, a little 
 borax added to the boiling liquor is usually beneficial. 
 
 Skins should be allowed to drain before fat-liquoring, 
 and the fat-liquor added to the goods quickly whilst the 
 drum is in motion. About half an hour is sufficient for 
 the leather to absorb the fatty matters, and a little 
 experience in handling the skins will soon indicate the 
 proper time and quantities required. 
 
 At the completion of this process the skins are care- 
 fully folded grain out straight down the back, and 
 allowed to lay on a suitable horse for a day, or more, 
 to enable the fibres of the leather to have the full benefit 
 of impregnation with the greasy matters. 
 
 Dyeing Black. — After the fat-liquoring operation the 
 skins are then ready for dyeing black. This may be done 
 either by brushing them with the " striker " on the table, 
 or by passing the skins through the logwood and iron so- 
 lution in suitable vats or trays. Some manufacturers have 
 also tried dyeing chrome goat in the drum, but the writer 
 prefers the tray method for several reasons, which would 
 take up too much space here for discussion. The dyeing 
 liquor varies somewhat in composition, but the following 
 is a safe formula for a black striker : Dissolve, by boiling 
 in 40 gallons of water, 5 lbs. of copperas and about 
 24 ozs. of blue vitriol, adding 1 lb. of ground nut-galls. 
 The skins are first folded down the centre grain out, and 
 perhaps slicked down with a smooth glass to protect the 
 flesh side as much as possible, and are then passed in 
 small packs through a strong logwood liquor, which is 
 all the better if boiled with a little fustic wood. After 
 this they are worked through the striker in a dilute form 
 until a deep black is obtained. As the iron striker is 
 rather inclined to roughen the grain if used too strong, 
 care must be taken to guard against this. It is more 
 difficult to obtain a good chrome black than would be 
 supposed, and the dyeing should be executed in a light 
 part of the works, and entrusted to the care of one 
 who has had some experience in the matter, otherwise 
 "bronzing" or an ugly- looking grey will be the result. 
 
34 o LEATHER MANUFACTURE. 
 
 After the skins are dyed a fine deep black they are well 
 rinsed through a tub of cold water, horsed up, and 
 allowed to drain. 
 
 An American authority gives the following method of 
 combining fat-liquoring and black dyeing in the drum. 
 The black is composed of warm logwood liquor, in which 
 5 lbs. of gum arabic are dissolved, whilst 8 lbs. of 
 copperas are dissolved in another vessel. The gum and 
 copperas solution are then mixed with 25 gallons of 
 strong logwood liquor. When the skins have received 
 the fat-liquor the black liquor is added to the skins 
 whilst the drum is in motion, which is then run for 
 another five minutes ; the skins are then washed in cold 
 water and struck out in the ordinary way. 
 
 Putting or Striking Out. — At this stage the skins 
 are put out or extended by machine, the machine shown 
 on Fig. 73, with the vertical rising table, being the 
 most suitable. During the last year or two, however, a 
 new machine has been on the market for the purpose, 
 for which a much greater output of work is claimed. 
 This consists of an arrangement by which four tables 
 are kept in motion on the one machine, and under certain 
 conditions it answers well, although some users allege 
 there is hardly time for proper spreading, feeding, and 
 taking off the skins. 
 
 The skins should at this stage be struck out moder- 
 ately tight and laid out flat, grain side up, when they are 
 given a light coat of equal parts of glycerine and water, 
 spread on with a suitable wad of some soft material or a 
 sponge. 
 
 In this condition the skins remain for a few hours, and 
 are then reset or again struck out. This time they 
 should be well extended, and all rough and uneven 
 grain removed if the final surface is to be smooth and 
 fine. 
 
 Oiling and Drying. — The struck-out skins are then 
 taken to a warm room for preference, and a coat of oil 
 applied to the grain side. This should be of the best 
 quality, and if reliable neatsfoot is to be had it is, perhaps, 
 
CHROME LEATHER MANUFACTURE. 341 
 
 the best all-round oil for the purpose. There are, of 
 course, other good oils on the market, but the damage 
 likely to be caused in the leather by unsuitable oil is so 
 great that any new oil should be at first experimented 
 with only on a very small scale. 
 
 The oiled skins are next dried out in a heated chamber. 
 Opinions differ as to the efficacy of sharp drying, but the 
 belief is common that the quicker the drying the less 
 likelihood the oil has of either setting on the grain side, 
 or of " spueing " up to the surface on the finishing stages, 
 or even in the finished condition. As a matter of fact, the 
 amount £>f drying room required is so great in a glazed 
 leather works of any size that it is impossible to find space 
 enough to dry slowly, although it is always a good plan 
 to allow the drying chamber to cool down before the 
 goods are taken out. The method usually followed is 
 to stretch the skins out by the hind shanks on parallel 
 racks studded with sharp tenter-hooks. The work should 
 be so arranged that the skins are left to dry during the 
 night, and taken down in the morning, when they are 
 comparatively cool. In this condition the skins may be 
 stored for some time, and should improve with age, 
 although this ageing process is not as necessary as is the 
 case with alum-tanned leathers, which used often to be 
 kept for six months before finishing. 
 
 Glazed Kid Finishing. 
 
 Staking or Softening — The first operation in the 
 finishing of glace kid is to well soften the leather; the 
 process is known as staking, and is now almost always 
 done by machine (see Fig. 75). The name of the pro- 
 cess is derived from the fact that formerly it was done by 
 pulling the skin over an upright wooden stake, into 
 which was fixed a fairly sharp metal plate. In the early 
 days of glace leather making the workman used his knee 
 as well as his hands for the purpose, the operation being- 
 known as knee-staking. 
 
 To bring the skins into the right condition for staking, 
 they are covered for a few hours with damp sawdust and 
 
342 LEATHER MANUFACTURE 
 
 are then taken to the machine The principle of the 
 staking machine is simple, the leather being extended 
 and worked by a blunt knife, the jaws of the machine 
 opening and closing by an ingenious mechanical arrange- 
 ment. The work is, however, rather tiring, as the pull of 
 the staking knife has to be neutralized by the pressure of 
 the operator's body. Goat skins are usually staked 
 twice, once from neck to tail, and once " to the breath." 
 Care should be taken to see the shanks are opened out and 
 a good pattern given to the skin. Some tanners still 
 have their skins knee-staked after one machining, whilst 
 others have them sorted over, and any which seem at all 
 hard, worked over with a moon-knife or arm-stake. The 
 cost of hand work, however, is so great, that only in few 
 instances is it followed out, and it will probably soon 
 disappear altogether. If the skins are very fleshy after 
 staking they should be lightly fluffed on a wheel covered 
 with fine emery powder, but as a rule a good stiff brushing 
 on the flesh is sufficient before they are passed on for 
 trimming. This consists of removing the edge rags of 
 the skins with a pair of strong shears, and is quickly and 
 cheaply done by girls or women. 
 
 Seasoning. — -The softened and trimmed skins are then 
 prepared for glazing by being wiped over on the grain 
 side with a mixture known as a " season." This usually 
 consists of blood or albumen solution, to which is added 
 colouring matter in the shape of logwood decoction, ink, or 
 black aniline dye. It is a mistake to give the leather too 
 much seasoning ; the idea should be simply to bring the 
 leather into condition for the subsequent glazing process. 
 Many seasons are sold ready prepared ; but for the benefit 
 of those who prefer to make their own, the following will 
 be found useful : — 
 
 6 qts. logwood liquor ; 
 
 2 „ ox blood ; 
 
 \ pt. orchil ; 
 
 2 pts. water ; 
 
 \ „ ammonia ; 
 
 \ „ milk. 
 
CHROME LEATHER MANUFACTURE. %$% 
 
 Another — 
 
 5 gals, logwood liquor ; 
 5 ozs. copperas ; 
 \\ pts. blood ; 
 5 ozs. glycerine ; 
 8 „ ammonia. 
 
 In many factories girls are employed for the seasoning, 
 and their nimbleness and lightness of touch makes them 
 very suitable for the work. In summer time the addition 
 of some cheap antiseptic, such as phenol (carbolic acid), 
 will keep the seasoning from becoming offensive. The 
 season should be spread evenly and lightly with a soft 
 pad and the skins hung up to dry. 
 
 Glazing. — This being practically the last operation care 
 must be taken to render it effective. Glace goat glazing 
 may be called a skilled business : in any event, the pro- 
 portion of bad work makes it an expensive matter to teach 
 operatives the process, and none but those of a high order 
 of intelligence should be employed. 
 
 A good deal depends upon the machine used for 
 the purpose, and the one in general use is known as 
 the " Bower." This is built almost entirely of wood, the 
 pressure of the glazing-glass being regulated by a foot 
 lever and a rocking arrangement fitted with springs at 
 the head of the machine (see Fig. 79). 
 
 Iron machines, such as the type shown at Fig. 78, give 
 great satisfaction for the heavier leathers, such as box- 
 calf, &c. ; in fact, some tanners use them for the first 
 glazing of kid, but taken all round the wooden " Bower," 
 by reason of its resiliency and cheapness, is the best 
 appliance for the glace leather maker to put into his 
 factory. The work, however, is rather trying, as the soft 
 leather has to be "humoured" to the work with the 
 hands, whilst in the case of the old-fashioned stiffer 
 leathers, like levant, the leather stood out boldly under 
 the pounding action of the polishing tools. Good super- 
 vision pays in glazing, and new beginners should only 
 be entrusted to do common goods for the first glazing. 
 
344 LEATHER MANUFACTURE. 
 
 After the skins have been glazed once they are then 
 again lightly seasoned, hung up to dry, and glazed the 
 second, and, if necessary, the third time. This practically 
 completes the process, although it is an advantage in 
 some cases to wipe over the grain with a clean oily rag. 
 This helps the finish to stand moisture and handling- 
 better, and slightly softens the leather, but is optional, 
 and is not followed out in many factories. 
 
 This, then, is the end of black glace or glazed goat 
 manufacture. Enough has been said to give readers a 
 good idea of the process, and given good skins, material, 
 machinery, and skilled supervision, a saleable article may 
 be made by following out the directions set forth. 
 Mention should be made, however, of the fact that even 
 after the leather is made, the chances of commercial 
 success are much improved by careful measuring and 
 grading the skins into the proper classes. Goat skins 
 vary greatly in size, substance, texture, and fineness of 
 grain, and the selection and grading is a work only to be 
 found out by exrjerience in the markets catered for, and 
 should be done by trained sorters, or by the principal 
 himself, who fully realizes the responsibility of this final 
 operation. 
 
 Dyeing Fancy Shades on Cheome Goat. 
 
 Before passing on to a brief review of the processes in 
 vogue for chroming box-calf, &c, it would be well to 
 give a few hints on the treatment of chrome goat skins 
 which are intended for colouring. As before mentioned, 
 the skins are sorted in the " blue " condition, i.e. after 
 they have been struck out from the final washing after 
 chroming. The dyeing is usually carried out in the 
 drum or paddle, solutions of aniline dyes being used for 
 the purpose. Methods differ a good deal, but the writer 
 has found the following to give good results. First, 
 mordant the skins in a weak solution of some tannin. A 
 mixture of cube gambier and fustic extract of about 5 
 
CHROME LEATHER MANUFACTURE. 345 
 
 per cent, of the wet weight of the skins, with enough 
 water at about 140° Fahr., will produce a good foundation 
 for most of the ordinary shoe colours. Sumac extract is 
 also useful for the same purpose. These materials should 
 be carefully dissolved and the skins drummed in the 
 solution for about twenty minutes. The skins are then 
 either drained or lightly struck out and fat-liquored. In 
 some cases the fat-liquoring is done after the dyeing, but 
 if the liquor is at all alkaline, the colour is stripped more 
 or less, and often a nondescript sort of shade is the result. 
 
 The hot fat-liquor is, as in the case of black skins, 
 added -to the drum whilst the goods are in motion, the 
 quantity being less, however, and regulated to suit the 
 requirements of the particular sort of skin under treat- 
 ment. After the fat-liquor has done its work the surplus 
 water is run off and the dye liquor added. The writer, 
 in actual practice, found it an advantage to take the 
 skins from the drum, and to fold them straight down 
 the ridges with the grain outwards. About one-third of 
 the hot dye liquor is put in the drum, the skins quickly 
 entered and the drum started, and the remainder of the 
 dye added in successive portions. The time occupied by 
 the dyeing is about a half to three quarters of an hour. 
 Although both the basic and acid colours may be used 
 for dyeing chrome leather, the acid range is preferred 
 by many, especially where the water is hard. There is a 
 wide range of these latter, and excellent shades can be 
 obtained by a mixture of acid yellows, brown, &c, shaded 
 with a little blue or green. The amount of dye required 
 of course varies, but from 3 to 6 ozs. per dozen goat skins 
 is usually sufficient. An American authority says that 
 chrome tanned skins may be very satisfactorily coloured 
 with sulfamine dyes, which require no mordant, and pro- 
 duce full, clear, and uniform shades of colour. 
 
 In dissolving the aniline dyes care should be taken to 
 see they are well strained through a fine muslin cloth 
 before the solution is added to the skins in the drum, 
 otherwise the undissolved particles are apt to get on the 
 grain of the leather and cause unsightly blotches. 
 
346 LEATHER MANUFACTURE. 
 
 Much space might be taken up with a variety of so- 
 called formulae for dyeing, but in the writer's opinion this 
 would be of little practical value, owing to the differences 
 in the requirements of the market, the uncertainty in the 
 nomenclature of the dyes, and the various methods of 
 working. Most of the aniline dye manufacturers keep a 
 special range of colours for chrome leather, and are, as a 
 rule, only too glad to furnish what information they can 
 on the subject. Mention, however, might be made of a 
 new dyeing process by what are known as the Corichrome 
 mordants. These have been put on the market by the 
 Chemische Fabrik Guestrow of Mecklenberg, the English 
 agents being Messrs. W. and C. Pantin, 147, Upper Thames 
 Street, London, E.C. These have been used with success 
 on the Continent, and shades produced by the Corichrome 
 mordants are said to be fast to light and almost fast to 
 soap and alkali. No change is said to take place in the 
 shade in the subsequent fat-liquoring in the drum — not 
 even when an alkaline fat liquor is used. The shades 
 themselves are actually determined by the Alizarine or 
 fast mordant dye-stuffs used in the dye-bath (grounding- 
 bath), and are perfectly developed by the subsequent 
 treatment in the Corichrome developing bath (fixing-bath). 
 
 There seems to be a great future before this method of 
 chrome-leather dyeing, as it promises to do away with 
 many of the difficulties, so far incidental to the process, 
 which are many and formidable. 
 
 After dyeing the skins are sometimes fat-liquored — if 
 this has not been done before as just described — and, 
 whethef fat-liquored at this stage or no, they are struck 
 out, glycerined, reset, oiled and dried just as described 
 for black glace. 
 
 The finishing is much the same, but it is often necessary 
 to " top-up " the grain with some fairly strong solution of 
 colour, after the first staking, to produce the exact shade 
 required. The " season " used, too, must obviously be 
 different, and the writer has found nothing better for the 
 purpose than a weak albumen solution, tinted with a suit- 
 able dye. Dry albumen for the purpose should be left to 
 
CHROME LEATHER MANUFACTURE. 347 
 
 dissolve in cold water, and kept sweet with a little dis- 
 solved phenol. This should be made in a moderately 
 strong solution, and diluted to the consistency required 
 with cold water, and applied with a soft sponge or rag, 
 carefully and evenly. 
 
 The final staking and glazing is followed out in the 
 same manner as described for black work, more care, if 
 anything, being used to keep the skins clean and of even 
 shade. Experiments, of course, should be on a small 
 scale, and frequent tests made before deciding to put a 
 large pack of valuable skins out for any particular shade. 
 
CHAPTER XXVIII. 
 
 BOX-CALF MANUFACTUBE. 
 
 Striking-out and Shaving. — Fat-Liquoring. — Dyeing Black. — Finishing 
 Operations. 
 
 The preparatory stages of chrome calf manufacture are 
 much the same as for wax or kid calf, special care being 
 taken to rid the pelt of lime, &c. For this reason the 
 excrement pure or bate is often supplemented by wash- 
 ing the skins in lactic acid solution, or the bran drench, 
 the final scudding being also very carefully carried out. 
 Some tanners also give the skins a pickle of acid and 
 salt before chroming, claiming for this, that it makes a 
 softer and fuller leather. About 50 lbs. of salt and 
 about 5 pints of sulphuric acid dissolved in sufficient 
 water is enough for one hundred skins, the skins being- 
 pickled in about four to six hours, and the surplus liquor 
 drained off before the goods are entered into the chrome 
 bath. 
 
 Salt is also often given the skins in the drum before 
 chroming, or in the chrome bath, as it tends to keep the 
 grain from becoming wrinkled and drawn in the process, 
 and produces a softer leather. It also keeps the fibre of 
 the pelt open, and helps the penetration of the chroming 
 liquor. 
 
 Calf skins may either be chromed by the two-bath 
 method, as described for goat skins, or by what is known 
 as the one-bath method. This latter greatly simplifies 
 the process as it avoids the uncertainties of the chemical 
 
BOX-CALF MANUFACTURE. 349 
 
 action incidental to the two-bath method. Various chrome 
 liquors are now on the market, but the first one of any- 
 great value was introduced by Martin Dennis, of America, 
 and is still sold under the name of " Tanolin." Accord- 
 ing to his original patent his liquor is obtained as 
 follows : — First, a solution of neutral chrome chloride is 
 obtained by solving a certain amount of chromic oxide 
 in hydrochloric acid, care being taken that there is always 
 a surplus of chromic oxide, i.e. there should always be 
 more chromic oxide present than the added amount of 
 hydrochloric acid is able to solve. To this solution 
 caustic soda, or, better still, bicarbonate of soda, is care- 
 fully added until a permanent precipitate of chrome 
 hydroxide is formed. 
 
 In this manner chrome-oxychloride or basic hydro- 
 chloric chrome oxide is obtained, a compound easily 
 soluble in water, which very easily parts with the super- 
 fluous chromic oxide, especially in the presence of bodies 
 possessing great affinity to chromic oxide ; for example, 
 gelatinous hide substance. Besides chromic oxide the 
 solution also contains common salt (sodium chloride), 
 which is formed by adding the bicarbonate of soda to 
 the hydrochloric chrome oxide. The presence of salt is 
 of great use in the tanning process, as it prevents the 
 swelling of the hides in the liquor, and helps to promote 
 the tanning process. Very often more salt is added to 
 the bath to ensure a good tannage. By these means a 
 stock of tanning liquor is obtained which is suitably 
 diluted before the skins are placed into same. The pro- 
 cess is mostly carried on in paddles, beginning with a 
 fairly diluted solution, and adding more of tne stock 
 tanning liquor from time to time, until the skins are 
 struck through a green colour in the thickest part. This 
 process generally lasts from ten to forty-eight hours, 
 according to the substance of the skins. The surplus 
 of acid in the skins is neutralised by giving them a 
 bath containing either calcium carbonate, lead carbonate, 
 barium carbonate, or similar substances. 
 
 A good formula published some time ago by Professor 
 
350 LEATHER MANUFACTURE. 
 
 H. R. Procter is as follow : — Take 10 per cent, (of the 
 weight of the skins) of chrome alum, and solve same in 
 a sufficient quantity of water, and solve separately 1\ to 
 3^ per cent, of soda. Add sufficient of the soda solution 
 to the chrome-alum solution until a permanent precipitate 
 of chrome oxyhydrate begins to form, and then add a 
 small quantity of common salt. 
 
 A writer in the Leather Trades Review states that he 
 has also obtained excellent results from a chrome liquor 
 prepared in the following manner : — Ten parts of chrome 
 alum are solved in sufficient hot water, and the solution 
 allowed to cool down, then a separate solution of three 
 parts soda is made. Add sufficient soda solution to the 
 chrome-alum solution until a permanent precipitate of 
 chrome hydroxide appears, and then add lactic acid 
 until the precipitate is just solved, and a clear liquor 
 is obtained. 
 
 With this solution make a fairly weak bath to start 
 with, and, after allowing the skins to paddle for a couple 
 of hours, add more of the chrome solution, continuing 
 to do so at short intervals until the skins are struck 
 through a greenish colour. The old bath may be used 
 for a new lot of skins, and a new bath made into which 
 the second lot of skins are placed when the first bath is 
 used up, and so on. 
 
 Amongst the various ready-made chrome liquors on the 
 market the writer has heard that prepared by Prenzlau's 
 Fabrikwerke, Hamburg, spoken well of. This is sold 
 under the name of " Corin," and the following short 
 description of the method of its application may be taken 
 as being fairly representative. The skins are first placed 
 into a 4 per cent, solution of " Corin," and are allowed to 
 paddle, then more " Corin " is added at short intervals 
 until all in all about a 10 per cent, solution is obtained, 
 in which the skins remain until tanned. The Vacuum 
 Oil Co., Ltd., York House, Norfolk Street, Strand, 
 London, W.C., also sell a one-bath chrome liquor which 
 has given great satisfaction to makers of box and willow 
 calf. 
 
BOX-CALF MANUFACTURE. 351 
 
 Generally speaking, all one-bath chrome liquors are 
 sold in a highly concentrated form, and the makers give 
 pretty accurate directions as to their employment, and 
 in some cases even send out competent instructors to 
 introduce them. 
 
 Both the paddle and drum are used in box-calf tan- 
 ning, the latter perhaps being, on the whole, the most 
 convenient. After tanning, the skins are well washed 
 in a borax solution of about 2 lbs. per cent, of pelt 
 weight, and finally in clean water until they are free 
 from salt and acid. 
 
 Strifting-out and Shaving. — The skins are then well 
 struck out, as described in the former chapter on glace- 
 goat manufacture, and are now shaved. This is now 
 almost always done by machine, and a good operator can 
 do from fifteen to twenty dozen skins per day, if the 
 leather is in good order, and does not require much 
 reducing. Care should be taken to see the cutting- 
 cylinder has suitable knives and is in good condition ; 
 the grinding of the emery wheel should, as far as possible, 
 be carried out when the skin is not actually under treat- 
 ment, otherwise the particles of steel may cause trouble 
 at a later stage, especially if fancy colours are to be 
 produced. It is convenient after shaving to weigh the 
 skins, as it furnishes a base for the calculation of the fat- 
 liquor, &c, later on. Care should also be taken that the 
 leather is not allowed to get dry, for it is impossible to 
 damp chrome leather back, as is the case with vegetable 
 tanned leather. 
 
 The skins are often at this stage blue-backed in the 
 drum, logwood, methyl violet, nigrosine, &c, being used. 
 
 Pat-Liquoring. — This is done in much the same manner 
 as already described for goat leather, the oily emulsion 
 being added in a heated condition to the goods in the 
 drum. Olive, castor, and neatsfoot oils are used in con- 
 junction with various soaps, &c. Turkey red oil is also 
 used, but probably the best all-round results are obtained 
 from neatsfoot oil and egg yolk. The quantity of liquor 
 given the skins varies a good deal, but averages from 
 
352 LEATHER MANUFACTURE. 
 
 about 5 to 10 per cent, of the shaved weight. This, 
 however, is a point best found out by experience. 
 
 A good quality fat-liquor soap recommended by 
 Professor Procter is made as follow: — 2 lbs. of caustic 
 soda are solved in about 8 pints of water. This solution 
 is poured into 20 pints of castor oil, previously heated to 
 86° Fahr., continually stirring the whole time until the 
 soap becomes thick ; after this, the tub containing the 
 soap is covered and allowed to remain overnight in a 
 warm place. The soap is now ready for use. It is as 
 well, but not essential, to melt the soap again before use 
 in a jacketed pan containing a stirring apparatus. By 
 means of this apparatus a better and more even mixing 
 of the soap is obtained. 
 
 The following recipes for fat-liquors have also been 
 collected and published by a writer on the subject : — 
 
 1. One pint neatsfoot oil and 1 pint cod oil are stirred 
 together with 1 pint of a 10 per cent, solution of soda, 
 and this mixture is poured into a hot solution of 3 lbs. of 
 soap chips in 6 pints of boiling water, continually stirring 
 the whole time. Five to 10 per cent, of shaver's weight 
 are then added to the necessary amount of water, i.e. for 
 100 lbs. of leather (shaver's weight) about 10 gallons of 
 hot water are taken. 
 
 2. 4 lbs. of soft soap are solved in 1 gallon of boiling 
 water, then add \\ lbs. of degras and f lb. of soda pre- 
 viously solved in water. Five to 10 per cent, of this 
 mixture is thinned with the necessary amount of water 
 as above. 
 
 3. 5 lbs. of soap chips are solved in sufficient boiling 
 water, then warm 4 pints of neatsfoot oil, and stir same 
 into the soap solution. Dilute the emulsion as above. 
 
 4. Dilute 6 lbs. of soft soap in boiling water, then add 
 5 pints of linseed oil to same, continually stirring until 
 a good emulsion is obtained. Dilute same as above. 
 
 5. 10 lbs. of soap chips are solved in boiling water, then 
 add 4 gallons of neatsfoot oil, and 10 lbs. of egg yolk 
 when it has cooled down sufficiently; stir until thoroughly 
 emulsified, and dilute as above. 
 
BOX-CALF MANUFACTURE. 353 
 
 6. Fifteen parts of olive-oil soap are emulsified with 
 4^ parts of olive oil, and diluted as above. 
 
 7. For fancy shades of colour the following fat -liquor 
 has been recommended : \ per cent, castor-oil soap or 
 olive-oil soap and f per cent, castor oil are stirred together 
 until properly emulsified and diluted as above. 
 
 8. The following fat-liquor is recommended by Jettmar : 
 3 lbs. of castor-oil soap, 2£ lbs. of glycerine, 1£ lbs. of 
 castor oil emulsified with 10 pints of boiling water. 
 
 Whatever fat-liquor is employed, it should be added 
 warm to the goods in the drum whilst in motion, a fresh 
 liquor being either made by boiling it under a steam-pipe 
 or by mixing in an emulsifier. 
 
 The liquor is best added by a suitable arrangement at 
 the side of the drum, which allows it to go through the 
 hollow axle. If the drum is warmed up, so much the 
 better, and it will be found that practically the whole of 
 the fatty matter of the liquor will have been absorbed in 
 about twenty minutes to half an hour. 
 
 Dyeing Black. — After fat-liquoring, the skins are dyed 
 black, much the same process being used as that described 
 for glace goat. The skins are folded grain out from head 
 to tail, passed first through a strong warm logwood de- 
 coction, and then quickly through a black or iron striker. 
 A good striker consists of 5 lbs. of copperas and 1| lbs. of 
 blue vitriol dissolved in 20 gallons of boiling water. 
 This is made up to 40 gallons, and about \ lb. of ground 
 nut-galls added. The following iron blacks have also 
 been published by an experienced writer on the subject : — 
 
 1. Solve 10 lbs. of iron vitriol (copperas) in 8 gallons 
 of water, and then add sufficient ammonia until a greenish 
 precipitate begins to form ; add acetic acid in small 
 quantities until the precipitate vanishes, and a clear yellow 
 solution is obtained, which, when applied to the skins 
 with a brush, will give a fine deep black. 
 
 2. A cheaper black is obtained by filling a barrel 
 three-parts full of old hoop iron, which should be devoid 
 of rust, adding about 4 gallons of water and about 4 pints 
 of vinegar. Place the barrel in a warm place, and after 
 
 2 A 
 
354 LEATHER MANUFACTURE. 
 
 about ten days fermentation sets in, which may be noticed 
 by the froth which collects on the surface. The froth 
 should be removed from time to time, and in about three 
 weeks' time the black is ready for use. Before applying 
 it to the skin, about equal parts of stale beer should be 
 added to the black to thin it down. 
 
 3. Another good black is obtained by solving 4 parts 
 of iron vitriol and 1 part of copper vitriol (sulphate of 
 copper) in 20 parts of water, and adding 3 parts of stale 
 beer. 
 
 The blacking process may also be done by brushing 
 the solution on the skins, which are sleeked out on a table, 
 or the black may be given in a tumbler. A good deal 
 depends on the general arrangement of the work, and no 
 definite rule can be laid down. Some manufacturers 
 claim good results by the use of aniline blacks, and it is 
 certain there is not the tendency to brittle grain, such as 
 occurs at times with the iron striker on black goods. 
 Others state the iron striker gives the best all-round 
 results ; but the operation should be conducted by a 
 skilled dyer. If aniline blacks are used for blacking 
 after fat-liquoring, a little acetic acid must be added to 
 the dye solution until it is slightly acid. This will 
 counteract the effect of the alkali given by the fat-liquor 
 soap to the liquor. In dyeing chrome calf in a tumbler 
 a 1 to 1^ per cent, solution of the aniline black is given, 
 and 2 to 3 per cent, of salt added. The temperature 
 should be kept up to about 140° Fahr., the time occupied 
 being about half an hour. 
 
 After the skins have been dyed, they are carefully 
 rinsed in water, and set or struck out by hand or 
 machine. They are then given a coat of warm neatsfoot 
 oil on the grain side, and sharply dried in a heated 
 chamber. Many tanners prefer to strain the skins out 
 on wooden frames before drying, and doubtless this 
 gives a better measurement, and preserves the pattern 
 on the skin much better than would otherwise be the 
 case. 
 
 Finishing Operations, — When the skins are dry they 
 
BOX-CALF MANUFACTURE. 355 
 
 are taken to a cool room and allowed to lay for a few days 
 until they are wanted. They are then slightly damped 
 by being covered with moist sawdust, and staked. The 
 method and machine used for the purpose is much 
 the same as that described for glace goat. The work, 
 however, is harder, and a good deal of judgment has to be 
 used to avoid over-softening the flanks and bellies of the 
 skins. The skins are then hung up and dried slightly, 
 and restaked, after which the edges are trimmed with 
 sharp shears. 
 
 Box-calf is then given a seasoning, i.e. some suitable 
 solutionis rubbed on the grain to prepare it for the sub- 
 sequent glazing. Nearly every tanner has his own formula 
 for the purpose ; but the following will be found reliable : 
 6 ozs. of nigrosine dissolved in 5 gallons of water ; add 
 2 pints of bullock's blood, 5 ozs. of glycerine, and 8 ozs. 
 of ammonia. 
 
 Another recipe : 5 ozs. of copperas are dissolved in 
 5 gallons of logwood liquor ; add to this 2 pints of blood, 
 5 ozs. of glycerine, and 8 ozs. of ammonia. 
 
 A good formula used with success on the Continent is 
 as follows : Beat up the white of three eggs, and then add 
 2 pints of logwood solution ; well strain, and add 1^ pints 
 of ox blood and J pint of milk. Weak solutions of albu- 
 men and linseed decoction are also sometimes used, these 
 latter, however, being more suited to seasonings for fancy 
 colours, where the above materials are not suitable. 
 
 In seasoning, only sufficient of the mixture should be 
 applied to the grain with a suitable pad to enable the 
 glazing to be executed properly, otherwise the latter 
 process will not be a success, whilst the excess of season- 
 ing is likely to peel off in the subsequent boarding. 
 When the season has properly penetrated, the skins are 
 then glazed by machine. There are several types in use, 
 and each make possesses useful features. The pressure 
 used in glazing must not be too great, otherwise the 
 glazing glass is apt to leave marks on the skin which are 
 difficult to remove. 
 
 After the first glazing is complete, the skins are grained 
 
356 LEATHER MANUFACTURE. 
 
 by means of the ordinary cork-covered pommel or arm- 
 board. In box-calf it is usual to grain two ways only, 
 once from the head to the tail, and then from belly to 
 belly. It should be noted, too, that it is often advisable 
 in the case of coarse flanky skins to lightly emboss with 
 a suitably engraved roller before graining ; this prevents 
 a coarse, unsightly " break," but only sufficient pressure 
 should be used to assist the formation of the natural 
 grain, as an artificial-looking break is strongly objected to. 
 
 After graining, the skins are again seasoned lightly ; 
 care should be taken the season is not applied too strong, 
 and a shank should be tested once or twice before season- 
 ing the whole lot, and the season modified or weakened to 
 suit requirements. After the second seasoning a second 
 glazing is given, first with a fairly heavy pressure, and 
 finally with just sufficient pressure to remove the tool 
 marks, streaks, &c. A final light boarding or graining 
 completes the process, and after the skins have been 
 sorted into qualities and sizes, the goods are ready for 
 the market. 
 
 In conclusion, it may be added that methods in vogue 
 vary a great deal, but if the above directions are followed 
 out, and practical common sense applied where modifica- 
 tions are necessary, there is no reason why a good saleable 
 article should not be turned out. The chrome process, 
 however, requires constant attention to get uniform 
 results, and experiments on a small scale are advisable 
 until success can reasonably be anticipated. 
 
CHAPTER XXIX. 
 CHAMOIS, OR OIL-LEATHER MANUFACTURE. 
 
 Preparation and Frizing. — Drenching. — Stocking or Milling in Oil. — 
 Pressing and Washing. — Finishing. — Chamois Glove Leather. — 
 Bleaching. — Tucking.— Colouring. — Buff Leather. — Liming.— Pre- 
 paring and Milling.— Scudding and Wash-house. — Buck Skin Dress- 
 ing. — Milling or Stocking. — Scudding and Wash-house. 
 
 The manufacture of "chamois," or oil-leather, is still 
 one of the most important branches of the leather in- 
 dustry, and an enormous home and export trade is done 
 in this material. The preservative or tanning principle 
 is not well understood, but it probably depends upon an 
 oxidation of the fats with which the raw pelt is treated. 
 It should be mentioned that oil tanning is one of the 
 oldest methods known in the preservation of animal 
 skins, and is still practised to this day by savage races. 
 
 Chamois leather is now usually manufactured from the 
 flesh splits or " linings " of the sheep skin, whilst white, 
 or " buff " leather, '"formerly used so extensively for 
 military accoutrements, is made from heavier hides by 
 the same process with slight modifications. The manu- 
 facture of chamois is mainly in a few large hands, as the 
 plant is rather expensive, and the amount of capital re- 
 quired considerable. Most tanners utilize the entire sheep 
 skin, the grain side being tanned with sumac and sold 
 under the name of "skiver" for a variety of cheap pur- 
 poses, whilst the flesh split is either turned into chamois 
 or " pickled " with sulphuric acid and salt for export as 
 the position of the market demands. 
 
358 LEATHER MANUFACTURE. 
 
 Sheep skins are first de-wooled by the fellmonger, and 
 eventually collected by the dresser, who sorts them 
 for the most suitable purposes. Those intended for 
 splitting are given a further liming to plump them, and 
 are then split on a machine with a rapidly vibrating 
 knife. Assuming the flesh splits are to be dressed as wash 
 or chamois leather, the process is as follows : — 
 
 Preparation and Prizing. — After splitting, the linings 
 are again put into lime, the lime-pits being so arranged 
 that the solutions are of a gradually progressive strength. 
 The goods are drawn frequently and the lime strengthened 
 as required. This stage of liming usually lasts from ten 
 to fourteen days, according to the class of skins and their 
 condition. The linings are at the end of this time firm and 
 in good condition for frizing, and all rough flesh and 
 roughness can be easily removed with a sharp knife on 
 the beam. Unskilled labour is often utilized for this 
 purpose, and the operation is also done by machinery ; 
 but it is doubtful if much real saving is effected. Skins 
 badly frized are said to require more oil and to want extra 
 work in the grounding operation. 
 
 Drenching. — This process is usually carried out in tubs 
 or vats, although in some of the larger works the drum or 
 paddle is used. According to a writer in the Leather 
 Trades Review, the tubs used are from half to two-thirds 
 filled with water at a temperature of about 70° to 80° 
 Fahr. To this water is added one to one and a half 
 buckets of scalded bran or meal, the bucket reckoned as 
 holding about three gallons. Previous to drenching, the 
 skins are well washed, either in a drum or paddle, through 
 which an abundant supply of clean water is kept running. 
 This will free them from surplus lime and other objection- 
 able matter, and show a saving in the amount of bran 
 required. The skins are then placed in the drench tubs 
 and are continuously stirred, though it is much quicker 
 to use the paddle for the purpose. This will accomplish 
 the deliming or drenching process in about six hours, 
 against twelve to twenty-four required in the tubs. No 
 definite rule can be laid down as to the amount of 
 
CHAMOIS, OR OIL-LEATHER MANUFACTURE. 359 
 
 drenching required, but an experienced workman will be 
 able to tell when the process has been carried far enough 
 by the feel and general appearance of the skins. 
 
 When the skins have been drenched, they are well 
 pressed to remove surplus moisture and grease. This is 
 usually done in an hydraulic press, the skins being 
 arranged between plates, sacking, and wood blocks, the 
 whole process taking about an hour. 
 
 Stocking or Milling in Oil. — When the skins are ready 
 for milling or stocking — the process being done in the 
 machine shown at Fig. 6 (page 111) — each skin is well 
 shaken -out to get rid of adhering bran or meal, and they 
 are allowed to cool by being thrown on the floor, care being 
 taken to avoid getting them dirty. They are then stocked 
 for about an hour to get them in uniform condition. 
 Then they are taken from the stocks and a three-gallon 
 pail of cod oil is got ready, also a sprinkler made of 
 heather sprigs. With this, one operative sprinkles 
 the skins, whilst another gradually throws the skins 
 into the stocks until sufficient oil has been given. They 
 are then milled for three or four hours, when it will 
 be found the skins are covered with soap, and will also 
 have a soapy, slippery feeling when handled. The 
 skins are now drawn from the stocks and taken to the 
 sheds for air-drying, no artificial heat being applied at 
 this stage. 
 
 After about a day's steady drying the skins are again 
 stocked and sprinkled with oil as before, the time being 
 usually three hours. They are now drawn and stoved at 
 a temperature of about 100° Fahr., the operation resulting 
 in making the skins a brownish colour. This process 
 of stocking and drying is repeated several times, until 
 the final heating off, when the skins are hooked by the 
 neck on ranges very closely in the drying stove. In this 
 stove the heat is raised to about 150° to 160° Fahr., when 
 a sharp, astringent odour will be given off. 
 
 The skins are then thrown, whilst in the heated con- 
 dition, in bins or casks, well trodden, and covered with 
 sacking to retain the heat. The temperature will at once 
 
360 LEATHER MANUFACTURE. 
 
 begin to rise, and the skins will require most careful 
 attention. The millman should go frequently from bin 
 to bin and note the temperature. At intervals they are 
 turned by casting them into another bin, the workman 
 using gloves for the purpose, and the goods well trodden 
 down by a lad. This is repeated until the skins are 
 heated off, a point only indicated by experience. 
 
 Care should be taken that there is no surplus oil or 
 moisture on the goods, or damage is very likely to result. 
 The workmen should also wear goggles to protect the 
 eyes, as the vapour arising from the skins is irritating. 
 Sufficient goods should be always available to keep up 
 the process of heating, otherwise parts of the leather will 
 remain green, and will become drawn when treated 
 with the alkalies later on. When the goods have 
 assumed a characteristic dark-brown colour they are 
 spread around to cool, and are ready for pressing and 
 Avashing. 
 
 Pressing and Washing — The skins are then thrown 
 into a vat of water at a temperature of about 110° Fahr., 
 and well pressed in the hydraulic press. Grease will soon 
 begin to exude, and, later on, the substance known as 
 sod oil, all of which being valuable, is carefully collected 
 and treated further if necessary. 
 
 When the skins are sufficiently pressed, they are then 
 well washed in an alkaline solution prepared as follows : 
 For ten dozen skins, dissolve 4 lbs. of soda ash and 2 lbs. 
 of soda crystals in sufficient water at a temperature of 
 120° Fahr. The washing is often done in a paddle, about 
 twenty dozen skins being paddled for about two hours. 
 The goods are now wrung out and the liquor run 
 away. Fresh water is then run in the paddle and the 
 heat raised to 130° or 140° Fahr., and the skins given 
 another hour's washing. In most places some arrange- 
 ment is made to save the liquor — the first being especially 
 valuable — as this contains emulsified fats which are 
 worth recovering. 
 
 Wash-leathers may either be dried after the second 
 washing or given a further liquor to improve their 
 
CHAMOIS, OR OIL- LEATHER MANUFACTURE. 361 
 
 pliability. A practical writer on the subject gives the 
 following method of preparation : Having run off the 
 second liquor, make a third in paddle as follows : in a 
 small mixer or tub put 10 lbs. of cod oil (about 1 gallon), 
 add 20 lbs. of soft soap ; stir the two well together till 
 the mixture becomes stiff, then add one gallon of boiling 
 water until all soap, oil, and water are thoroughly blended. 
 Take of this liquor 3 to 3^ gallons to the paddle of goods, 
 and run for one hour ; then draw goods, take to either 
 wringing machine or hydro-extractor. 
 
 The skins are now taken to the drying sheds to be 
 dried with air or artificial heat, being hooked by the 
 two hind shanks on tenter-hooks from rail to rail ; when 
 dry they are taken to warehouse, and are now called 
 " crust " leather. 
 
 For " fleshers," or heavier linings, the process is 
 prolonged, and in washing the amount of materials 
 is increased. 
 
 Finishing; — In this condition the goods, as crust 
 chamois, are often sold to dressers and others, who make 
 a speciality of finishing for the market. The skins, after 
 sorting into sizes and qualities, are first staked, either by 
 the arm or upright stake, and are then levelled and 
 worked out by the moon-knife on the perch ; this last 
 operation being a skilled operation, and one requiring 
 great care. The skin is extended in every possible way 
 by the workman until it is thoroughly soft, and the fibre 
 can be pulled in any direction. 
 
 The goods when finished are then carefully trimmed 
 with shears around the edges, and the holes, where 
 possible, sewn up by hand or machine. They are then 
 carefully sorted into qualities and sizes — the sorter 
 stretching each skin as much as possible — and eventually 
 put up into bundles of thirty, known technically as a 
 "kip." These kips vary in price, some of them coming 
 down as low as five shillings, whilst others may be quoted 
 at fifty shillings. 
 
 Chamois leather is almost universal in its application, 
 being used by the tailor, the shoemaker for boot linings, 
 
362 LEATHER MANUFACTURE. 
 
 the fancy leather goods maker, and for an endless variety 
 of domestic purposes. A large export trade is also done 
 in this material, America being one of the best customers 
 of England, whilst Australia, Germany, France, Italy, 
 and South America also take large quantities from our 
 market. 
 
 Chamois Glove Leather. — The stoutest and best skins 
 are often sorted out in the crust condition, and finished 
 specially for glove leather. They are first well grounded 
 with a moon-knife on the side which is the most suitable 
 for colouring. After this " paring " operation, they are 
 then carefully run on an emery wheel to produce a fine 
 smooth surface, when they are ready for bleaching. 
 
 Bleaching.— In order to produce good clear colours on 
 chamois it is necessary to bleach the leather. This is 
 still done by exposure to light, the process taking two or 
 three days in summer and as many weeks in winter. The 
 skins are first well saturated with a warm solution of 
 soapy water, made by dissolving a sufficient quantity of 
 soft soap in it, and are then taken to a suitable grass 
 plot, the side to be bleached and coloured being exposed 
 to the light. This operation is repeated daily until the 
 desired result is obtained, when the goods proceed to the 
 next operation, known as tucking. 
 
 Tucking — The skins are then thoroughly wetted 
 through in warm water, and are then either wrung or 
 run in a hydro-extractor, shook out, and hung on a suit- 
 able wooden horse. Each skin is then separately immersed 
 in a vat of boiling soapy water, and when sufficiently 
 tucked, the skins are at once taken to a drying shed heated 
 up to a temperature of 120° Fahr. When thoroughly dry 
 they are taken to the stakers, who work the skins out 
 either on the upright or by the crutch stake, when they 
 are lightly gone over again on the emery wheel. The 
 best size advised for this purpose is a wheel of about two 
 feet nine inches wide by about nine inches in diameter, 
 which should run at a good speed. 
 
 Colouring.— Chamois skins are usually coloured one at 
 a time by spreading them on a convex lead or zinc-covered 
 
CHAMOIS, OR OIL-LEATHER MANUFACTURE. 363 
 
 table. The colour is usually of a mineral base, ochres 
 and umbers being often used. Of late years more or 
 less successful attempts have been made to use coal-tar 
 colours, and in some hands good results are said to have 
 been obtained. The usual mineral colour is mixed to a 
 thick consistency in a sort of paint, and applied evenly 
 with a suitable brush, care being taken to keep the 
 colour well stirred. 
 
 The leather is, after colouring, then dried off in a 
 hot stove, cooled off in the air, and again staked. It 
 is then well dusted or " beaten " over a heavy wooden 
 stool to free it from dust, and again run over an emery 
 wheel, care being taken the emery used is fine, so that 
 the final appearance of the leather may be soft and 
 velvety. 
 
 The skins are now recoloured and dusted as before 
 described, and in some cases the three operations involved 
 are again carried out. 
 
 Dark shades are often obtained on chamois leather by 
 running the skins in a paddle or drum in a weak bark 
 liquor or aniline dye, being subsequently, when dry, 
 topped up or brushed over with a weak solution of aniline 
 colour. 
 
 Deep shades of brown are also at times obtained by 
 hanging the skins in closed chambers, and subjecting the 
 leather to the action of ammonia gas, generated by first 
 running chloride of ammonia solution into a suitable 
 vessel in the chamber, and, later, hot lime liquor to 
 liberate the ammonia. 
 
 Buff Leather. — Although buff leather has been to 
 some extent discarded for British army accoutrements, 
 yet a fair trade is still done in this material. Hides 
 of a suitable class are used for its manufacture, the 
 general principle being much the same as in chamois 
 leather. According to a practical writer on the subject 
 in the Leather Trades Beview, the process is as 
 follows : — 
 
 Liming. — The hides are put into old or weak limes at 
 first, handled daily, and the strength of limes increased 
 
364 LEATHER MANUFACTURE. 
 
 for about ten days, when it will be found the hair and 
 cuticle can be removed by pushing over beam with 
 unhairing knife. After unhairing they are put into fresh 
 and stronger limes for a few days, which makes the hides 
 firmer, when they are taken to either splitting or frizing 
 shop. 
 
 If split only a thin or light grain is taken off, or if 
 frized the grain is only just taken off, as the flesh part of 
 hide only is used in making buff or oil leather. After 
 frizing, the goods are again returned to the lime-pit for a 
 short time until ready for milling. 
 
 Preparing and Milling. — The hides are drawn from 
 the pit, and in place of being drenched are hung out on 
 lines to partially dry out the water in them, by action 
 of sun and air in summer, or in winter dried in a warm 
 atmosphere. The reason they are not drenched is be- 
 cause a firmer leather is required. When sufficiently 
 dry they are taken to the stocking mill. On arrival 
 at the mill they are thrown into stocks and milled for 
 about two hours to distribute the moisture evenly and 
 to soften them, as they have become hard or horny in 
 drying. 
 
 They are now drawn from the stocks and laid out to 
 cool. Meantime, to every 3 gallons of cod oil, 1 quart of 
 freshly sifted slack-lime is added, and the mixture well 
 stirred. The hides are now thrown into the stocks, whilst 
 another man sprinkles them with the mixture of oil and 
 lime. After the stocks or fallers are full, run for three to 
 four hours, when it will be found the hides are covered 
 with a kind of lime soap, and have become warm by 
 the constant beating. 
 
 The hides are now drawn, and taken and hooked in a 
 warm stove of a normal temperature, fitted with a blast 
 fan, until sufficiently dry. This oiling and milling- 
 operation is repeated several days, also the drying, but 
 gradually increasing the warmth of stove each time, until 
 the final milling preparatory to heating off. As the 
 hides cannot be packed into tubs or bins to heat off, they 
 are hooked in a very hot stove with a large coke fire in 
 
 
CHAMOIS, OR OIL-LEATHER MANUFACTURE. 365 
 
 the centre, or heated with iron furnace pipes laid on 
 bricks about twelve inches from the ground and all round 
 the stove inside, the furnace door being let into wall at 
 exterior of wall of building. The latter is the better plan 
 with pipes which get red-hot, as with the fire in the 
 centre of the stove it is a very disagreeable operation to 
 make up fires on account of heat and the offensive, 
 irritating smell (acroclin) given off from the hides. After 
 the hides are thoroughly heated off, i.e. when they are 
 hard and dry and of a dirty brown colour, they are ready 
 for washing. 
 
 Scudding and Wash-house. — The hides on arrival in 
 the wash-house are put into vats containing the following 
 solution : To every hide 3 lbs. of socla ash and 1 lb. of 
 soda crystals, with a sufficiency of water at a temperature 
 of 112° Fahr. The hides are laid out flat in this vat for 
 twelve to fourteen hours ; they are then drawn, and the 
 scudder takes them in hand, who places them over a beam 
 and well pushes and presses them to remove as much 
 grease as possible. 
 
 They are now returned to the washers, who have 
 heated the liquor they were drawn out of, and also 
 added another lot of soda ash and soda crystals. This 
 is now put into the drum (when the temperature is 
 about 120° to 130° Fahr.). The hides are now thrown 
 in and run for about one and a half to two hours, 
 when they are drawn and the liquor run off. This 
 liquor, also that from the scudding beam, is worth 
 saving. 
 
 Another lot of liquor is then made up as follows : ^ lb. 
 of soda ash and \ lb. of soda crystals with sufficient 
 water ; raise temperature to about 130° Fahr. The hides 
 are now drummed in this liquor for about one and a half 
 hours, and are now drawn and put into a vat containing 
 a fat-liquor in same proportions to number of gallons of 
 water as in treating chamois linings. They are left in 
 this liquor about an hour, and are taken to the drying 
 shed, which is preferably heated with warm air distributed 
 with a blast fan. 
 
366 LEATHER MANUFACTURE. 
 
 When dry they are ready for bleaching and " tucking," 
 which is carried out in the same way as in treating chamois 
 linings. But as hides cannot be handled by grounders 
 over a perch with a moon-knife, they are taken by 
 grounders and put on emery wheels or special hide 
 machines to put the fine smooth face on them. 
 
 Buck Skin Dressing. — Buck or deer skins are limed 
 exactly as hides, first for twelve to fourteen days to 
 remove hair and cuticle. After sufficient liming they 
 are ready for drenching, first washing in clear water 
 to rid of surplus lime, then drenched with bran liquor 
 and pressed to get rid of surplus liquor in the same 
 way as in treating chamois. They are now ready for 
 milling. 
 
 Milling or Stocking. — The milling is carried out on 
 the same lines as in milling chamois (no lime being 
 added to the oil), but the milling is prolonged as the 
 skins have the grain on, having been neither split nor 
 frized, and it is better, even after buckskins are heated 
 off, to let them lie about for some time to feed on the 
 oil before taking to scudding or wash-house. 
 
 Scudding and Wash-house. — The skins on arrival in 
 wash-house are immersed in tubs or bins of hot water 
 placed at side of press, and are now pressed in the usual 
 way (as in pressing chamois). On removal from the press 
 they are immersed in tubs holding about 30 gallons, a 
 hot liquor having been made up with soda ash and lime 
 at a temperature of about 112° Fahr. overnight. They 
 are put in loosely, and are left in this liquor till the 
 grain begins to almost rot, when the skins are drawn and 
 placed one at a time on a narrow beam, the beam not 
 being more than ten to twelve inches in width, when the 
 scudder takes a very keen knife and pushes the grain off, 
 only taking very narrow strips or shavings off straight 
 down the skin from neck to tail or vice versa, and 
 frequently shifting the skin ; hence the necessity of a 
 narrow beam. After scudding they are ready for the 
 final washing. The scuddings or shavings are worth 
 saving, being rich in grease. 
 
CHAMOIS, OR OIL-LEATHER MANUFACTURE. 367 
 
 The skins, having been immersed in strong alkalies in 
 the scudding shop, do not require the second immersion, 
 but are drummed with 30 lbs. of soda ash to each hundred 
 skins in a sufficiency" of water at a temperature of about 
 120° to 128° Fahr. After thoroughly washing they are 
 fat-liquored, as in treating chamois. 
 
 When dry they are finished off on emery wheels or 
 buck machines in the same way as in finishing hides. 
 
CHAPTEE XXX. 
 CUBBYING. 
 
 The Scouring-kouse. — The Shop. — The Curriers' Knife. — Currying Kip 
 Leathers. — Waxed Kip Butts. — Sorting and Bounding. — Soaking 
 and Softening. — Be-tanning. — Drum-stuffing. — Setting. — Finishing. 
 — Stoning and Starching. — Graining. — Waxing. — Top-sizing. — 
 Currying Satin or Glove Shoe Leather. — Soaking and Splitting. — 
 Buffing. — Blacking and Setting. — Finishing Satin or Glove Leather. 
 — Levant Leather. — Soaking and Splitting. — Setting, Buffing;, and 
 Embossing. — Blacking. — Seasoning and Glazing. — Oiling. — Curry- 
 ing Various Leathers. Wax Calf Skins. — Calf Skins for Memel. — 
 High Shoes, Black Grain. — Split Cow-Hides for Brown Bags. — 
 Blocking Boot-fronts. 
 
 The art of currying consists in dressing skins, after they 
 are tanned, for the purposes of the boot and shoe maker, 
 coach and harness maker, saddler, and others, by which 
 they acquire the pliancy, smoothness, grain, and colour 
 necessary for the important purposes to which they are 
 to be applied. The operations of the currier are chiefly 
 mechanical, and form a distinct branch of the trade. Many 
 light leather manufacturers, however, combine the art of 
 currying with the other branches of their business. The 
 curriers' shop requires plenty of space, subdivided into 
 many compartments, for carrying on the numerous pro- 
 cesses connected with the trade. If possible, the lower 
 part of the building should be devoted to those operations 
 in which large quantities of water are required, as soaking, 
 scouring, and cleansing the leather. 
 
 The Scouring-house is supplied with a series of wide 
 tubs, in which the leather undergoes a preliminary soak- 
 ing ; there is also a large, flat, and smooth stone, about 
 8 feet long by 4J feet wide, supported by woodwork or 
 masonry, upon which the leather is scoured. This stone 
 has a slight inclination, so that the water used in scouring 
 may freely run off the table on the opposite side to that on 
 
CURRYING. 369 
 
 which the workman stands. A block of sandstone, called 
 the rubstone, from 2 to 3 feet long- and 9 or 10 inches wide, 
 fixed on a trestle, is employed by the workmen for sharpen- 
 ing their various tools. A finer stone, called the clearing- 
 stone, is used to remove the marks produced by the coarser 
 stone. 
 
 The Shop, as it is called, is a light and generally spacious 
 apartment, in which is the beam (Fig. 55) on which the 
 leather is shaved. The beam is 
 constructed of a stout block of 
 wood, upon which the work- 
 man stands, and into one end 
 of which a strong- plank of 
 hard wood is firmly secured, 
 at an angle of 80° to 90°. The 
 working beam is about one 
 foot in width, and its height 
 is regulated according to the 
 height of the workman, each K 55> 
 
 man having his beam adjusted 
 to suit his convenience. On the face of this upright, as it 
 is called, a piece of hard and perfectly smooth wood — ■ 
 generally lignum nice — is attached, and which agrees with 
 the edge of the knife used in the operation of shaving. It 
 is of the utmost importance to the operator that his knife 
 and beam should be in perfect order, otherwise the skins 
 would be liable to injury from the irregular action of the 
 tool. 
 
 A series of tables, the plane surfaces of which are 
 usually made from mahogany or marble, are firmly 
 fixed to the floor of this apartment, near the windows, 
 so that the workmen may have the full benefit of 
 the light. At a short distance from each table, and 
 behind the workman, is a wooden trestle, across which 
 the currier throws each piece of leather after he 
 has worked it on the table in any of the dressing opera- 
 tions. There are many compartments in the currying- 
 shop, each being devoted to some special branch of the 
 business, and furnished with one or more tables and trestles., 
 
 2e 
 
370 LEATHER MANUFACTURE. 
 
 and the particular tools required for the operations to be 
 conducted therein. 
 
 The Curriers' Knife. — The most important tool is the 
 curriers' knife (Fig. 56), which consists of a blade of 
 fine steel, tempered in a peculiar way, 
 and firmly riveted between two plates 
 of iron. It is furnished with two 
 handles, one of which is horizontal and 
 the other vertical, the latter being 
 Flg - 56 ' held in the left hand. The method of 
 
 giving an edge to this tool, which is remarkable, is thus 
 described by Ure : " This instrument is taken to the 
 rubstone and ground to a perfectly sharp edge by succes- 
 sively rubbing it forward and backward, care being taken 
 to keep the edge true, that is straight. When this has 
 been satisfactorily accomplished, it is still further rubbed 
 on a Scotch or Welsh stone called the clearing -stone, until 
 the scratches of the rubstone disappear. In this operation 
 a fine thread or wire forms on the edges, for the knife has 
 two edges, which must be carefully got rid of, after which 
 it is wiped dry and the edges greased with tallow or oil. 
 The workman then takes a strong steel, and placing him- 
 self on his knees, he fixes the knife with the straight 
 handle against any firm body and the cross handle between 
 his knees ; then holding the steel in both hands, he care- 
 fully rubs it forward and backward the whole length of 
 the edge. During this operation the knife is gradually 
 raised by means of the cross handle until it is nearly per- 
 pendicular ; by this means the edge is turned completely 
 over. If the knife is not well tempered the edge thus 
 obtained will be irregular or broken, in either of which 
 cases it is of no use whatever. To keep the instrument in 
 proper order requires great skill on the part of the currier. 
 The edge is so delicate and liable to injury 
 O^^U^" that it cannot be used more than a minute 
 
 or two without losing its keenness. To 
 lg ' * restore this a very carefully prepared small 
 steel is used (Fig. 57) ; the point of the steel is first run 
 along the groove and then along the outside edge. 
 
CURRYING. 
 
 371 
 
 The knife is used as shown in Fig. 58. the operation 
 here depicted being known as hand-shaving. The 
 process is now often done by machine, which, together 
 with the modern methods of currying, are now dealt 
 with. 
 
 Fig. 58. 
 
 Currying Kip Leathers. — Whilst it must be acknow- 
 ledged the old methods of currying produced a leather 
 which proved serviceable in wear, experience has shown 
 that its manufacture has lately produced little profit to 
 the currier. The principles underlying the treatment of 
 leather by the currier remain, it is true, much the same, 
 but machinery has displaced hand labour to a great 
 extent, whilst some processes have either been dispensed 
 with altogether or very much shortened. It is only fair 
 
372 LEATHER MANUFACTURE. 
 
 to say that the advance in leather manufacture is largely 
 due to American initiative and enterprise, for our markets 
 are flooded with cheap-dressed leather from the United 
 States, whilst American machinery is being sold all the 
 world over, and copied by competitors everywhere. 
 
 The extent of the American trade in leather is clearly 
 shown by a reference to official statistics, and it speaks 
 volumes for the cheapness and excellence of the trans- 
 atlantic product, if we remember that 515,686 cwts. of 
 rough and dressed leather were bought in 1905 by Great 
 Britain alone. The business is an enormous one, and it is 
 obvious that, with such competition to face, the British 
 currier has had to get into line with the American, and it 
 is proposed to here briefly describe a few of the methods 
 now in vogue in our more up-to-date leather works. Need- 
 less to say, they vary according to the particular market 
 catered for, or the fancy of the foreman or manufac- 
 turer, but the principles are much the same, whilst the 
 machinery employed is similar in large and small estab- 
 lishments. As a chapter is devoted elsewhere to the 
 consideration of modern leather manufacturers' machinery 
 it will not be necessary to give needless details here, 
 beyond just the points required to make matters under- 
 stood. Since this book was first written, the causes alluded 
 to above and the introduction and popularity of the chrome 
 process have lessened the consumption of stout upper 
 leather enormously. In fact, many go so far as to say that 
 the total extinction of wax leathers, i.e. leathers finished 
 black on the flesh side, is only a question of time ; others, 
 it is true, do not hold this view, for wax leathers possess 
 qualities which make them specially suitable for the 
 heavy hard wear of the mechanic, agriculturalist, and 
 other wearers who require a boot fairly waterproof, with 
 a certain amount of porosity and at a low price. For 
 these reasons, then, waxed leathers are still popular, but 
 have to be produced at a much lower price than was 
 formerly the case ; and it is proposed in this chapter to 
 give an outline of the processes involved in the currying 
 of kip butts, a leather which has even now a large sale. 
 
CURRYING. 373 
 
 Kips, it should be said, are the hides of the native 
 cattle of India; these are imported in enormous quan- 
 tities both in the raw and partly tanned condition ; and 
 to a large extent the prosperity of Leeds as a leather 
 centre has been built up on the successful exploitation 
 of this special trade. 
 
 Waxed Kip Butts. — It will be more convenient for 
 the purposes of discussion if we consider the kips here 
 alluded to are those which are bought in the half- 
 tanned condition by the currier. This leather is im- 
 ported by merchants into England, and at intervals 
 auction- sales are held in London, a sample of the 
 goods being first inspected by the prospective buyer. 
 The buying is mainly done by the buyers' broker, 
 whose small commission is more than saved by his 
 expert knowledge placed at his clients' disposal, whilst 
 it is also an advantage that competitors should not 
 know what other buyers are obtaining. The tanned 
 kips are selected into qualities and weights and care- 
 fully catalogued, and the buyer naturally selects the 
 various " marks " and average which suits his particular 
 trade. The larger buyer of Indian kips also purchases 
 what are known as " original bales " direct of the im- 
 porters, but as these hides run rather irregular in 
 weight and substance, it is more economical for the 
 smaller currier to buy the selected classes at the 
 London sales. The character of the Indian tannage 
 varies greatly with locality ; for instance, Bombay 
 kips are clean and well got up, but somewhat spongy, 
 whilst Madras are hard, and often badly plastered on 
 the flesh side. 
 
 Sorting and Rounding. — We will assume, then, the 
 currier has obtained his kips, and that they are in his 
 warehouse. The first operation is to sort for the various 
 purposes required, throwing out all the badly-flayed and 
 branded kips for levant or lining leathers, or any purpose 
 where the perfect flesh side is not a sine qua non. After 
 sorting, the kips are "rounded" or cut up into butts, 
 
374 LEATHER MANUFACTURE. 
 
 shoulders, and bellies, the butts, as a rule, being the only 
 part sufficiently compact in the fibre to make waxed 
 leather. 
 
 Rounding is a process requiring great care and 
 judgment, and should only be undertaken by a man of 
 experience. No two kips are exactly alike in growth, and 
 it is easy to leave an inch or two on the offal which 
 should have been allowed to remain on the butt, or vice 
 versa. A rough idea will be gathered of the usual method 
 followed out in rounding kips by an examination of the 
 diagram shown in Fig. 14 (page 127). 
 
 After rounding the kips the butts are carefully 
 weighed and put up into " packs " or " lots " of about five 
 dozen. It is needless to say that a proper stock or ware- 
 house book should be kept of all lots going out, and that 
 the warehouseman should, on giving out the goods to the 
 currier for dressing, also give him the stock number, so 
 that track may be kept of the leather right through the 
 works to the finishing department. 
 
 Soaking and Softening.— On receiving his "lot," the 
 currier proceeds to soak or dampen down the leather ; it is 
 important this should be done with care, otherwise the 
 subsequent operation of shaving is rendered very difficult. 
 The leather should be given just sufficient water, so that 
 on doubling back the grain side, the moisture just oozes 
 out. In very cold weather it is an advantage to soak the 
 harder tannages of Indian kips in warm water. The 
 Madras leather especially is usually undertanned, 
 plastered with mud or grease on the flesh side, and so 
 compressed by various methods that it is often difficult 
 to get the leather to take the water at all unless it is 
 warmed. Of course, it goes without saying that excessive 
 heat must not be used, otherwise damage to the leather 
 is the result ; but it is a pretty safe rule that if the work- 
 man can bear his hands in the soak-tub, the water is not 
 too hot for the leather. 
 
 After soaking, the leather is usually allowed to lie in 
 pile for a few hours, so that the moisture permeates 
 evenly through the fibre. After this the kips are 
 
CURRYING. 375 
 
 softened in a clrum-tunibler, no further water being 
 added. This has the effect of taking the excessive stiff- 
 ness or " bone " out of the leather, thus rendering the 
 subsequent operation of shaving much easier. 
 
 Before shaving, however, the butts are cut down the 
 centre, and the two halves plainly marked on the grain 
 side with the stock number and the " fellow mark." This 
 is done so that the two halves may be matched up later 
 on in the currying process. 
 
 We now arrive at the shaving operation, which has 
 been fully explained at the opening of this chapter. 
 This important operation is, in many factories, still 
 done by hand, i.e. by the use of the double-edged 
 knife pressed smartly with a downward stroke on the 
 flesh side of the leather over a sloping lignum vitce 
 wood block (Fig. 58). The skilled kip-butt shaver levels 
 to some extent the inequalities of the leather, and at 
 the same time endeavours to pare out the veins, flaws, 
 and other defects of the leather. The shaving must be 
 free from knife-galls and scratches, the latter especially 
 showing up in a very unsightly manner when the leather 
 is finished. Generally speaking, the aim of the beams- 
 man, or shaver, should be to produce a fine and even 
 surface at the least possible loss of weight and appear- 
 ance. 
 
 The introduction of the splitting, and later the shaving 
 machine, has, however, affected the art of the old crafts- 
 man, and it seems only a question of time when the whole 
 of waxed leather will be shaved by mechanical methods. 
 Turning first to the splitting machine (see Fig. 54, page 
 322, and Fig. 68, page 412), wonder may be expressed that 
 this easy and cheap way of levelling leather has not long 
 since superseded shaving for wax leathers. Experience 
 has, however, taught that split leather does not produce 
 so fine and dense a fibre as that obtained by hand shaving. 
 It is true, kip butts are sometimes lightly split, but these 
 are invariably re-shaved, or "flatted," to minimise the 
 effect of splitting as much as possible. Still, where 
 excessive fineness of face is not an absolute necessity, it 
 
376 LEATHER MANUFACTURE. 
 
 is often advantageous and economical to take off a light 
 split from the rump part of the butt, as it obviously saves 
 both labour and material. No amount of work and 
 material will, however, make a badly split kip butt equal 
 in appearance and value to the shaved article, so that the 
 operation, if done at all, must be done with great care 
 and judgment. 
 
 As may be gathered from the chapter on leather- 
 dressing machinery, a good deal of shaving is now done 
 by machine. In fact, practically all the lighter upper 
 leathers which are finished on the grain side are now 
 shaved in this manner, but it is still an open question in 
 the minds of experts whether there is any great saving in 
 the use of the machine on waxed goods. As a matter of 
 fact, both hand and machine methods are in use by 
 equally progressive concerns; but it is fair to say that 
 some manufacturers of the very best waxed butts still 
 favour the ancient method of hand-shaving. The 
 objections urged by many against the shaving machine 
 seem to be much the same as those experienced by split 
 leathers. Still, the difficulties incidental to machine 
 kip-butt shaving have certainly been overcome by some 
 curriers who are turning out a good article. These 
 leather manufacturers now sort out the various weights, 
 and use different cutting cylinders to suit the substances 
 required, and apparently the finished wax leather appears 
 equal in every respect to the hand-shaved article. It 
 seems, therefore, extremely likely that it is only a 
 question of time when waxed leather as a whole will be 
 shaved by machine, for continual improvements are being 
 added, whilst the currier has profited by experience, and 
 year by year more fully understands the capabilities of 
 such profitable mechanical aids. 
 
 As shaving machinery is more fully dealt with else- 
 where, we will proceed to take our shaved butts to the 
 next operation. 
 
 Re-tanning. — As the butts are usually very under- 
 tanned, it is necessary at this stage to rectify this, other- 
 wise the leather will not take up sufficient grease, and will 
 
CURRYING. 377 
 
 be deficient in solid fibre. Various metliods are in use ; 
 some people lay the goods in pits with a strong tanning 
 liquor for a few weeks, whilst others are content to give 
 them a brief immersion in sumac liquor, or an hour or two 
 in a good strong tan liquor in a drum-tumbler. In many 
 large works the butts are well tumbled in a mixed tan liquor 
 composed of gambier and sumac, and perhaps myrobalans, 
 for six or eight hours. After this they are then again 
 drummed with a sumac and gambier liquor strengthened 
 up with sufficient good oakwood extract. After this 
 second drumming the butts are washed through a warm 
 sumac .liquor to brighten up the colour, and are then 
 allowed to drain for a few hours, when they are hung up 
 to dry. Various machines are in use for ridding the butts 
 of moisture before drying. In some works the hydraulic 
 press is brought into requisition, whilst others use a form 
 of squeezing machine. It is by no means certain, how- 
 ever, that these are an advantage for the purpose, as it- 
 is thought by some that the loss of certain solid matters 
 in the tannin leads to a loss of weight in the finished 
 leather. 
 
 In the olden days butts were after re-tanning scoured 
 out flesh and grain on the slate table by means of 
 sleaker and stock stone, when they were "sammied," 
 or half-dried, thoroughly stretched or " set " out on a 
 wooden or marble table, and stuffed on the flesh side by 
 applying a liberal coat of dubbin by means of a brush. 
 The butts were then dried out slowly, and then "tal- 
 lowed " on the grain side, or, in non-technical language, 
 rubbed over on the grain with a slight coat of dubbin. 
 Hand-stuffing has, however, been almost entirely super- 
 seded by a method known as drum-stuffing, by which 
 melted fats are mechanically worked into the leather in 
 the tumbler. This is really the most important modern 
 development of the curriers' art, and as such warrants a 
 full description of its technique. 
 
 Drum-stuffing. — The successful application of grease 
 to leather in the process of drum- stuffing depends upon a 
 variety of conditions, and much money has been lost 
 
378 LEATHER MANUFACTURE. 
 
 before the various points were fully understood. Even 
 now burnt leather is fairly common, although the intro- 
 duction of air-heated tumblers has greatly lessened the 
 risks common to the use of steam for the purpose. The 
 modern hot-air drum (see Fig. 70) is now often fitted 
 with a grease melting and mixing pan, and is so arranged 
 that the melted fats are fed automatically into the drum ; 
 other tumblers are fitted with both steam and hot air, 
 the former being useful for cleaning purposes. The main 
 advantage about the hot-air tumbler is that it can be 
 rapidly heated and cooled, the latter being often done by 
 injecting cold air. 
 
 To return, however, to the modus operandi of drum- 
 stuffing. The butts, after drying, are first carefully 
 weighed, and the amount of grease to be used calculated 
 on a percentage of this dry weight. After weighing they 
 are damped down again ; not too much water must be 
 given, or the leather will fail to absorb the grease, whilst 
 if the butts are too dry, the risk of burning is great. 
 After the butts are quickly dipped in the water they are 
 laid in pile for a day or two and carefully covered with 
 bagging. This has the effect of allowing the goods to 
 get into better condition, as the moisture becomes evenly 
 distributed. At the end of this time the butts are 
 slightly damped in the dry places with a brush, when 
 they are ready for stuffing. 
 
 A good deal might be written on the various materials 
 employed in drum-stuffing, for since it was found hard 
 greases, such as waxes, stearines, &c, produced a better 
 looking and heavier leather, the old-fashioned tallow and 
 cod oil have largely dropped out of the currier's list of 
 materials. However, it will be sufficient for our purpose 
 to give one or two representative stuffing mixtures and 
 their method of application. Generally speaking, the 
 firmer the leather is required the greater the proportion 
 of hard grease, wax, or stearine given to it. In America 
 it is known that as much as 80 to 100 per cent, on a dry 
 weight of the leather is worked in ; but English curriers 
 for various reasons do not, as a rule, obtain such results. 
 
CURRYING. 379 
 
 In drum-stuffing the drum is first heated up to the 
 proper temperature, say, about 130° to 140° Fahr., when 
 the condensed steam in the form of water should be 
 run off. 
 
 In the older form of drum the melted grease was put 
 in, and the damp leather stacked on the shelves, when the 
 door was securely fastened and the drum set in motion. 
 Another and better plan is to put the butts into the 
 heated drum and allow them to run without grease for a 
 few minutes ; this has the advantage of heating the 
 leather through, so that when the hot grease is subse- 
 quently added it does not coagulate on the surface of the 
 leather and thus prevent its penetration. In the more 
 modern form the grease is fed through the axle of the 
 drum whilst it is in motion. This is a much better 
 arrangement, as it prevents any single piece of leather 
 sticking to the side of the drum and thus only getting 
 partially stuffed. Kip butts should be run in the grease 
 from thirty to forty minutes, after which the drum door 
 is taken off and replaced by an iron grill or grate, and 
 the goods allowed to run another half-hour to cool down. 
 It is best, in order to get this result, to run the goods for 
 a few minutes, and then to stop the drum for another 
 short period, as this prevents the butts from being 
 knocked about too much, and thus parting with a portion 
 of the grease. 
 
 As before hinted, no two curriers use precisely the 
 same stuffing mixture, and a good deal of unnecessary 
 secrecy is observed with regard to their composition. In 
 the early clays, when drum-stuffing was introduced from 
 America, nothing but cod oil and tallow was used ; now 
 the number of greases used is legion. Good curriers 
 claim often to get as much as 50 to 70 per cent, gain 
 on the rough weight of kip butts by the use of such 
 materials as stearine, degras, or sod oil, paraffin wax, and 
 perhaps a little resin. The first mentioned is, of course, 
 the chief constituent, and splendid results are obtained in 
 quality and weight by the use of a stearine of about 
 100° Fahr. melting-point. One good and representative 
 
380 LEATHER MANUFACTURE. 
 
 stuffing mixture for kip butts is as follows : For 100 lbs. 
 of dry leather take, say, 10 gallons of stearine — or, if 
 tallow is used, say, 50 per cent, more — 1 gallon of sod 
 oil, and 5 gallons of degras. 
 
 It is, however, of little practical use to give other 
 formulas for stuffing mixtures, as everything depends 
 upon the tannage and the requirements of the market. 
 A great deal must be left to the judgment of the in- 
 dividual, but if the rules and methods given are carefully 
 followed out no loss or difficulty should be experienced. 
 Top much care cannot be given to the choice of good and 
 suitable stuffing materials, and experiments should be 
 carried out slowly at first, and on a small scale, as trouble 
 with leather does not always make itself manifest until 
 after the finished leather has laid in stock for some time. 
 
 Setting. — This is an operation which has to be done 
 quickly and thoroughly, so as to remove all stretch and 
 contracted grain. The methods in vogue differ slightly, 
 but as a rule the grain side is first well worked out on a 
 fiat table with a stock stone, and the flesh side then well 
 "canked" or extended with a suitable steel sleaker. The 
 grain is then again stoned and glassed with a rounded 
 glass in a suitable handle, and the butts hung up to dry. 
 (Some curriers prefer to cank them first, and after stoning 
 the grain allow the butts to slightly samm or dry, and 
 then reset. Some lay them in pile between the two 
 settings, and on the whole the best results perhaps are 
 obtained this way if the damp butts do not lay too long 
 and thus become heated. 
 
 In any event, drum-stuffed leather should not lay 
 about in the air long, as oxidation is apt to set in on the 
 exposed surfaces and cause unsightly stains. Machines 
 are now being used for kip butt setting, and once the 
 technical difficulties in the way are overcome, it is only 
 a question of time when hand setting will become 
 extinct. 
 
 Special stress has been laid upon the drum-stuffing 
 process owing to its revolutionary character as compared 
 with the old hand method, and also to the difficulty of 
 
CURRYING. 381 
 
 obtaining reliable working data upon it. However, 
 we will now assume our kip butts have been carefully 
 dried in the sheds. If this has been carried out with- 
 out the use of too much artificial heat, they should 
 be of a good colour and not inclined to crack on the 
 grain. If the grease has done its work, very little in 
 the way of rounding or " tallowing " is wanted, although 
 it is better to go through them and apply a little dubbin 
 where it is required. Some curriers lightly brush over 
 the flesh side with dubbin, and allow the butts to lie in 
 pile for mellowing purposes for about a month. The 
 butts are then ready for the final operation of finishing, 
 and as there is practically no grease on the surface of the 
 leather the old process of "making up" — necessary to 
 hand-stuffed goods — may be dispensed with. 
 
 Finishing. — Whitening is the first operation, and it is 
 interesting to note that since this book was first written the 
 whitening sleaker has completely ousted the light shaving- 
 knife for that purpose. The sleaker is much more con- 
 venient to use, and in skilled hands produces a better result, 
 besides taking less weight off the leather. The work is 
 now usually done on a glass or marble table, and if the 
 butts have been properly shaved, it is only necessary for the 
 workmen to just skim off the light nap or fibre which has 
 been raised by the previous processes. The workman, by 
 pressing the leather firmly against the edge of the table 
 with the upper part of his legs, proceeds to take a bold 
 sweeping stroke straight up the butt, and finishes up by 
 lightly skimming over towards the belly edge. 
 
 Whitening is greatly facilitated by first moistening 
 the surface of the leather by a weak soap solution ; 
 this is easily applied with a brush or sponge, and not 
 only greatly assists the workman, but helps to form 
 a fine and close surface. Good whitening is all- 
 important, and the work should be free from scratches 
 or " stabs," whilst every care should be taken to avoid 
 cutting too deeply into the leather, otherwise coarseness 
 of fibre is unavoidable. In most works the foreman 
 carefully looks over the butts after whitening, casting 
 
382 LEATHER MANUFACTURE. 
 
 out any which are badly done. Whitening is now often 
 done by machine, and good results are obtained by 
 the use of a special cylinder on the shaving machine. 
 The machine shown at Fig. 72 is also used for the 
 purpose. 
 
 Stoning and Starching.— After whitening, the butts 
 are stoned and sleaked over on the grain side to remove 
 any adhering grease, &c, and are then often trimmed 
 round the edges with a sharp knife to remove rough 
 edges. The currier then mates each half butt with its 
 proper fellow by examining the marks on the grain 
 side of the leather made before shaving. The butts 
 are also often buffed in places on the grain side if 
 this has not been done before whitening; this is a 
 great improvement to the commoner classes of goods, 
 and removes scratches and broken grain, which, if left, 
 look very unsightly. The butts may at this point be 
 given a weak coat of some mucilaginous solution, to 
 which is added a little colouring mixture, such as anatto 
 or some suitable aniline dye. This operation is techni- 
 cally termed "starching," although the solution used is 
 generally composed of glue and water. After the butts 
 have been hung up to dry, they are ready for graining. 
 
 Graining. — This process is fairly simple as applied to 
 kip butts for waxing, for, as a rule, the shoe manufacturer 
 requires the leather firm, so that it stands up boldly in 
 the boot. In most works graining is now done by cross- 
 ing and recrossing the grain of the leather with a cork- 
 covered pommel, the same tool being used for "bruising : ' 
 or softening. The old hand-graining board is now only 
 used for the lighter kind of leathers, such as sheep and 
 goat skins, a heavier and much more serviceable tool, 
 called the "arm board," being used for graining kip 
 butts. 
 
 Graining is so well understood that it is not necessary 
 to again take up space by describing it ; the primary 
 idea is to somewhat soften the leather, whilst the operator 
 should endeavour also to develop a small neat figure, 
 such as one is accustomed to see on grained calf skins. 
 
CURRYING. 383 
 
 Naturally the workman pays most attention to the hard 
 and close parts of the butts, as the less pressure put upon 
 the belly and shoulder parts the better, owing to the 
 comparative looseness of the fibre. 
 
 At this point the leather is for all practical purposes 
 well curried and ready for the final operation, although 
 some curriers prefer to apply a light soap solution, which 
 is well glassed into the flesh side before the butts are 
 passed on to the waxing-room for the final blacking and 
 sizing. In this state the leather is said to be "in the 
 russet," and it is in this condition the famous French 
 tannages of calf skins are exported, the final blacking 
 being put on in England or elsewhere. 
 
 ■Waxing 1 . — Here, again, every waxer has his own par- 
 ticular methods and ideas ; the principle involved is, 
 however, very simple, the idea being to produce a good 
 and deep black on the leather, with a modified gloss 
 which will stand the somewhat severe handling of the 
 shoe manufacturer. Some waxers use a sort of weak 
 paint composed of cod oil and lamp-black, to which 
 a little weak sumac liquor is added to facilitate matters, 
 whilst others prefer a soap solution as a medium for 
 the colouring matter. The soap colour is, perhaps, the 
 most useful, as it helps to produce the great desidera- 
 tum of the currier — a fine and smooth surface. With 
 this colour, too, there is no d auger of darkening the 
 leather, as is often the case when oil colour is used 
 in a warm room by a waxer who is anxious to show a 
 good grain of weight. But whatever colour is used 
 only enough should be applied with a brush to give a 
 good black, or it will be difficult to remove the excess 
 of "smut" or solid matter. This is usually done by 
 rubbing over the leather with the hand or a suitable 
 brush, and is a very necessary section of the waxiug 
 operation. After smutting, the butts are usually again 
 glassed and are then bottom sized, i.e. given a weak coat 
 of a properly prepared compound which is well rubbed 
 in with a glass tool. The composition of bottom sizes 
 varies greatly, but the following are practical, and if 
 
3»4 LEATHER MANUFACTURE. 
 
 modified to suit individual cases will be found very 
 useful : — 
 
 1 lb. best glue ; 
 
 1 „ flour ; 
 
 8 oz. soft soap ; 
 
 4 „ sugar of lead. 
 
 The whole of the materials are first dissolved in seven or 
 eight pints of logwood liquor, and incorporated by stirring 
 during cooling. 
 
 Another bottom size is prepared thus : — 
 
 10 pints of logwood liquor ; 
 1 lb. best glue ; 
 1 „ flour ; 
 \ „ soft soap ; 
 ^ „ sulphate of copper (" bluestone "). 
 
 Whatever bottom size is used, care must be taken 
 that it is used sufficiently weak, or trouble will certainly 
 arise when the final top-sizing is given to the leather. 
 In practice it is usual to first try both sizes experiment- 
 ally, and weaken down with water or a little dubbin if 
 found too strong. 
 
 Top-sizing. — After the bottom size has been well 
 glassed in and allowed to dry, the butts are then top- 
 sized. Only sufficient should be given to nicely cover 
 the leather, a special brush being used for the purpose. 
 Atter the composition has been applied, a fine smooth 
 surface is obtained by finally rubbing the still damp sur- 
 face with a leather-covered pad or a bare arm, the aim 
 being to obliterate the brush marks. The butts are then 
 hung up in a heated chamber and allowed to dry. A final 
 glassing and oiling with warm cod oil completes the pro- 
 cess, and if the methods outlined have been followed out, 
 a saleable article should be the result. If the sizing has 
 been well done with suitable materials, the surface should 
 improve with age, whilst the size should become tough, 
 
CURRYING. 385 
 
 and possess a " bloom " which is appreciated by buyers 
 of this kind of leather. 
 
 Before closing this chapter it may be as well to give a 
 typical top size for waxed leather. This may, as before 
 hinted, want slight modifications to suit individual re- 
 quirements, but it will be found a good working formula, 
 and as such worthy of note : — 
 
 1 lb. best glue ; 
 
 10 pints of logwood liquor ; 
 
 2 pints cod oil ; 
 2 oz. beeswax ; 
 
 6 shoe-finishers' heel-balls. 
 
 The glue is first soaked in a part of the logwood liquor 
 and then slowly dissolved by heat ; the other ingredients 
 are also dissolved in a separate vessel and added to the 
 glue solution ; both solutions should, of course, be first 
 carefully strained through a fine muslin cloth. Care 
 must be taken to keep the size stirred during the cooling 
 process, otherwise the final result will be unsatisfactory. 
 
 Another recipe : 1 lb. kid clippings ; 7 pints water ; 
 1 lb. glue ; \ lb. soft soap ; 4 ozs. beeswax ; 2 pints cod 
 oil ; \ lb. tallow ; 4 ozs. Venice turps ; 2 ozs. prepared 
 asphaltum. Prepare and mix as above. 
 
 In conclusion, it should be said that the manufacture 
 of wax kip butts has been gone into fairly fully, as their 
 manufacture represents the modern development of curry- 
 ing, and illustrates better than any other leather how 
 old-fashioned methods have been grafted on, as it were, 
 to the use of machinery and modern methods. The trade 
 is still a very large one in these goods, and as the leather 
 possesses qualities which are difficult to obtain in other 
 leather, whilst the supply of raw material is likely to 
 continue fairly abundant, it may be safely assumed that 
 not even the chrome industry will ever supplant this 
 valuable section of the orthodox currier's art. 
 
 Currying Satin or Glove Shoe Leather. — Under 
 various names a variety of most useful leathers are now 
 
 2 c 
 
386 LEATHER MANUFACTURE. 
 
 finished on the grain side. Satin leather has long been in- 
 cluded amongst British curried leathers, and satin calf used 
 to be highly esteemed. The term " satin " is sometimes 
 applied to a leather finished on the grain, the surface 
 of which has not been removed or buffed, whilst " glove " 
 shoe leather is usually understood to mean a leather 
 which has had the grain removed : both terms are, how- 
 ever, used in a somewhat arbitrary manner. It is claimed 
 for the buffing process that it adds to the wear of the 
 leather, as the hard natural outer surface of the dermis 
 soon becomes hard, and ultimately cracks. On the other 
 hand, it must not be forgotten that buffing immensely 
 improves the grain of the tanned leather by obliterating 
 barbed-wire scratches, frized grain, and other imper- 
 fections which curriers are painfully familiar with. 
 
 It may be mentioned here that the trade in glove hide 
 has assumed enormous dimensions, mainly owing to the 
 enterprise of the Americans, who, by the employment of 
 machinery, and perhaps a highly protected home market, 
 have been enabled to sell this leather at a very low price. 
 The American tanner, by specialising on side leathers 
 alone, has a decided advantage over his European com- 
 petitor, who is perforce obliged to handle not only kips, 
 but shoulders and bellies of different sizes and substances 
 for satin purposes. However, a good trade is still done in 
 grain leathers, and in the following summary it is proposed 
 to give an outline of the various processes employed, 
 which, although varying in different works, yet depend 
 on much the same principles. 
 
 Soaking and Splitting. — These operations are carried 
 out in precisely the same way as in the case of kip butt 
 dressing already described. In the case of the lighter 
 classes of kip offal, shaving only is necessary, which may 
 be either done by hand or machine. It might here be 
 mentioned that thin kip shoulders and bellies are often 
 dressed and blacked on the grain side, and are commonly 
 called " black grain ; " in this case, however, the outer 
 surface of the grain is not buffed away as in glove. 
 
 As a rule, it is only the stouter and rougher classes of 
 
CURRYING. 387 
 
 hide offal, or sides, which are worked up into satin or 
 glove, and as the leather is full in substance, it is well 
 adapted for splitting, whilst as the flesh split is also 
 valuable, it is obvious the saving is great. As before 
 hinted, successful splitting depends upon a proper pre- 
 paration of the leather, and too much care cannot be 
 taken in arriving at the proper amount of moisture it 
 should contain, or in the careful treatment of the leather 
 before the actual splitting commences. It is usual before 
 splitting, and after damping, to thoroughly extend the 
 leather by means of a suitable machine; this has the 
 effect of removing coarse grain, wrinkles, &c, which 
 would leave unsightly marks in the finished leather. 
 This object is obtained by stoning, or "jacking," out the 
 grain side of the leather on a machine of the grasshopper 
 type, such as is illustrated in Fig. 77. Small curriers 
 usually have a set of interchangeable tools for this piece 
 of plant, and amongst them a stout brass or stone sleaker, 
 which is very useful for preparing work for the splitting 
 machine. 
 
 Much might be written on proper splitting, but no 
 amount of instruction will possibly make an expert 
 splitter, who, by the way, is an invaluable adjunct to any 
 leather works. Glove leather is now invariably split on 
 the band-knife machine, and a good splitter is able to get 
 his leather sufficiently uniform to avoid any subsequent 
 levelling with the shaving knife, although it must be 
 acknowledged that for some classes of goods this latter 
 operation is an improvement. Two much care cannot be 
 taken by the operative in splitting, since any damage 
 clone is permanent. He should frequently examine the 
 leather as it passes through the machine, and immediately 
 rectify any errors in substance. The knife should also 
 be kept constantly sharp, and the bevel most suitable to 
 the grade of goods under treatment fully kept up. Pre- 
 cautions must also be taken to guard against the flying 
 emery dust from the grinding apparatus coming into con- 
 tact with the leather, or a good deal of discoloration will 
 be the result. As a rule, a smart boy attends the splitter, 
 
388 LEATHER MANUFACTURE. 
 
 and removes the leather as it comes through, the splitter 
 carefully feeding the leather on the other side. In 
 America the position is reversed, the chief operative 
 being the one who takes the leather from the machine. 
 In America, however, several splitting machines are 
 under the charge of one man, who is really responsible 
 for the quality of the enormous quantity of work turned 
 off by the machines. Another point about splitting 
 worthy of note is the necessity for a sharp removal of the 
 goods after the operation. It is a common fault to see 
 leather being left about near the machine for workmen 
 to walk on, or to catch the flying particles of emery from 
 the wheels. The machine, too, is well worth attention in 
 the way of extreme cleanliness, and it is a good rule to 
 see that every part is thoroughly wiped dry and rubbed 
 with an oily rag after the day's work. 
 
 After splitting, kip leathers are first re-tanned much 
 in the same fashion as described in the previous chapter. 
 Hide leathers, being fully tanned, do not require this 
 treatment, and are usually given a sumac bath in the 
 drum. This considerably mellows the leather, and enables 
 it to take a much greater quantity of grease in the sub- 
 sequent stuffing processes than would otherwise be the 
 case. After sumacing, the goods are scoured either by 
 hand or by one of the many scouring machines. As the 
 leather is to be blacked on the grain side, the removal of 
 the bloom is not of great importance, so that the scouring 
 may be pushed forward rapidly. After scouring, the 
 leather is either taken to the sheds for hand-stuffing, or 
 dried out if the process is to be done by the drum. Of 
 late years the former process has almost become extinct 
 in the larger establishments, owing to the cost and the 
 impossibility of getting in the weight as compared with 
 drum-stuffing. We will assume, then, drum-stuffing is 
 the process to be followed out. It will not be necessary 
 to again go into details, as they were fully described in 
 the chapter on Butt-dressing, but it cannot be too often 
 insisted upon that the greatest care is necessary in the 
 application and selection of the various greases if best 
 
CURRYING. 389 
 
 results are to be looked for. Some curriers make the 
 mistake of supposing that any old grease is good enough 
 for satin or glove leather ; but it is hardly necessary to 
 say the results are by no means as good as when good 
 fats, such as tallow or stearine, are used. The amount of 
 grease put into the leather varies a good deal, but may 
 be probably put at about 60 to 70 per cent., calculated on 
 the dry weight of the leather. Of course the whole of the 
 melted grease put into the stuffing-drum is not absorbed, 
 although a good currier loses very little. The gain of 
 weight in America is very much greater than in England, 
 as much as 90 to 100 per cent, being obtained on the 
 weight of the dry leather. This result is, however, 
 largely obtained by the use of hard stearines and waxes, 
 whilst the fact that the hemlock tannage is a good grease 
 absorbent is probably an important factor in its favour. 
 In stuffing satin leather the drum is heated up to about 
 140° to 150° Fahr. before the leather is entered, whilst it 
 takes about thirty or forty minutes for the melted fats to 
 be absorbed by the leather. After cooling down, as 
 already explained, the leather is set. In many places 
 this is done wholly or partially by machine, although if 
 the latter plan is favoured, the work has to be gone over 
 again by hand to remove the marks remaining. The 
 leather has to be in any case very fully extended both on 
 the flesh and grain. If this is not well done, the grain is 
 coarse, and the leather will probably be pipey and loose, 
 to say nothing of the greatly increased difficulty which 
 the buffer will experience in the removal of the outer 
 surface. The leather is then dried in the ordinary way. 
 
 Buffing. — Although this may be done by machine, 
 yet the process is so difficult that most curriers prefer 
 hand-buffing. Even the progressive American currier 
 has not yet fully conquered the question of machine 
 buffing, although the problem has had the serious atten- 
 tion of engineers for many years past. Still, for some 
 requirements a machine does the work well enough, and 
 a machine of the type described in the chapter on 
 Machinery (see Fig. 72) is often very useful for the 
 
390 LEATHER MANUFACTURE. 
 
 purpose. A long description of the machine is not 
 wanted here, but, roughly, it consists of a cylinder con- 
 taining an arrangement of spiral knives fixed at the end 
 of a pendulum, or vibrating arm, the whole arrangement 
 being worked over a sloping table. The leather under 
 treatment is laid over the sloping table, which is auto- 
 matically raised to meet the action of the cutting 
 cylinder by means of a foot lever. As a rule, machine- 
 buffed leather has to be gone over again by hand, as the 
 machine is apt to miss the thinner parts of the hide. 
 
 In hand-buffing the whitening sleaker is used, and 
 only expert workmen are trusted with the operation. 
 The grain is first damped with a soap solution, and the 
 buffer takes off very thin shavings from the surface. 
 Great care should be taken to avoid scratches, stabs, or 
 " run " marks ; otherwise the finished leather will be 
 unsightly and of lower value than would be the case with 
 good work. 
 
 Blacking and Setting. — After the buffing operation, 
 leather for glove or satin is then blacked. Different 
 curriers have different methods ; some mordant the grain 
 with a logwood solution, and apply the striking iron 
 liquor at once. The leather is then well set out on flesh 
 and grain, and after the latter had been dried, a solution 
 of some filling material is applied with a soft sponge. 
 For hide sides the following methods may be taken as 
 fairly representative, whilst it also obviates to some 
 extent the tendency toward pipey grain before alluded to. 
 Brush over the grain with a weak solution of logwood 
 liquor (about \ lb. to the gallon) to which has been added 
 a little ammonia. Then well set out the leather on the 
 table, which has previously been rubbed over with tallow 
 to make it stick. Care should be taken to give the side 
 a good pattern, and this is only to be obtained by the 
 workmen using the setting sleakers by following the 
 natural lay of the hide. After this setting, the leather 
 is again washed over with the logwood liquor, when a 
 coat of some suitable ink or iron liquor is given. The 
 sides are laid by in a pile, and are then thoroughly 
 
CURRYING. 391 
 
 canked on the flesh side, the grain being this time stuck 
 to the table by the use of oil. After this the sides are 
 again set on the grain side to the table, a coat of dubbin 
 being first brushed on to the latter. After a further 
 sleaking, to remove surplus particles, followed by a 
 glassing or pebbling, a coat of paste or bottom size is 
 applied with a sponge or brush. Various mixtures are 
 used, but the following will give excellent results, viz. a 
 quarter-pound each of best glue, oil, and flour, mixed 
 in about two quarts of hot logwood liquor. This is 
 a representative formula, but different tannages require 
 varied" pastes and sizes, and often want a good deal of 
 modification to suit individual requirements. 
 
 Finishing Satin or Glove Leather. — After drying out, 
 the leather is now whitened ; in some places this opera- 
 tion is done by machines, as they are quicker in their 
 action than hand labour. The same class of appliance as 
 that spoken of for buffing does whitening fairly well, 
 although opinions as to its merits vary considerably. If 
 the leather is to be whitened by hand, a slight skiving 
 over with the sleaker is sufficient, as in this case it is only 
 necessary to clean the flesh side for appearance' sake. 
 When the leather is whitened it is then trimmed at the 
 edges, and lightly bruised with the arm-board to soften 
 it. This operation is, of course, done from the grain side 
 so as to avoid raising the grain ; it requires care and 
 judgment, and very little pressure should be given to the 
 coarse and loose part of the hide. Satin is then again 
 sleaked down on the grain side with a dull sleaker to 
 remove the bruising marks, and glassed or pebbled as 
 preferred. The leather is then given a coat of finish in a 
 warm room and dried out very thoroughly. Some people 
 who prefer a dull finish use either a flour or gum solution, 
 a few drops of ammonia being added to it if any difficulty 
 is experienced in its application. A good finish may be 
 prepared as follows : In 4 quarts of logwood liquor dis- 
 solve 1^ lbs. of glue, 4 ozs. of brown soap, 3 pints of cod 
 oil, and 2 \ ozs. of beeswax. This is applied with a suitable 
 pad covered with cotton wool, over which is tacked a 
 
392 LEATHER MANUFACTURE. 
 
 piece of buffed leather. Extreme care must be taken to 
 avoid marks of any kind in the application of the finish, 
 as it is impossible to remove them later. The leather 
 after thoroughly drying is now again glassed, oiled with 
 warm cod oil, again hung up until the oil has penetrated, 
 when it is ready for the finished-leather store-room. 
 
 Satin or glove leathers, it is true, do not now enjoy the 
 popularity they did before the introduction of the chrome 
 tannage. Still, the trade is yet a good one ; and as the 
 leather is extremely useful for such work as the cheaper 
 grades of women's and children's footwear, it is very 
 unlikely it will ever become obsolete, and there is no 
 reason, if the above directions are carefully followed out, 
 why the reader may not get good results on this class of 
 leather, even if he has not been accustomed to this special 
 work. 
 
 Levant Leather. — Until the advent of chrome leather 
 the levant trade was a most important branch of the 
 leather-dressing industry, and even now kip curriers still 
 find it a useful addition to their business. The term 
 "levant" is usually applied to an embossed or printed 
 leather, finished on the grain side with a bright surface, 
 and dressed with oil only, i.e. not stuffed with fats and 
 greases as in the case of waxed leathers. This section 
 of leather manufacture provides a very useful outlet for 
 poor goods unsuitable for wax and satin, and very little 
 hand labour is required under modern conditions. 
 
 Soaking and Splitting. — Taking East India kips as 
 an example, the process is as follows : They are first 
 carefully soaked until the water just oozes out on sharply 
 pressing, and after lying in pile for a few hours they 
 are softened by a short drumming, and are cut straight 
 down the centre of the back. 
 
 They are then split evenly on the band-knife machine, 
 and are either first scoured or taken away for retanning. 
 This is invariably done in the drum, a mixture of 
 sumac, myrobalan, or gambier liquor being used, often 
 strengthened with a certain proportion of good oakwood 
 extract, This retanning is an important part of the 
 
CURRYING. 393 
 
 levant business, as India kips are very often undertanned, 
 and if this is not reckoned with, the finished leather will 
 be hard, and will refuse to take the necessary quantity 
 of oil to make it profitable. 
 
 Setting, Buffing, and Embossing, — After drumming 
 for about eight hours, either drain up the goods thoroughly, 
 press or squeeze by machine, or strike them out on the 
 flesh side. Then take them to the drying sheds and 
 lightly oil with linseed oil on the grain side and hang 
 up to samm. They are then well set by means of a 
 sharp sleaker on the flesh side, and hung up and dried 
 out, a'little oil being used to stick the kips to the 
 table. 
 
 "When fully dry go carefully over the grain side, and 
 carefully buff all broken grain, first slightly damping 
 the surface with a sponge and sleaking the place to be 
 buffed well first with a dull sleaker. After buffing 
 where necessary, sort the kips for printing, throwing 
 all those inclined to be "pipey" or coarse-grained out 
 for the heavier style of print, such as seal or big-star 
 grain. 
 
 The embossing or printing is now usually done by 
 means of a suitable engraved roller (see Figs. 81, 82), the 
 entire side being subjected to a fair pressure in passing 
 through the rollers. A better impression is obtained 
 if the leather is first damped slightly. The kips are 
 then dried out, and may be stored in this condition until 
 ready for finishing. 
 
 Blacking. — The goods are now dried out after all the 
 pleats made by the machine are carefully trimmed out, 
 or remedied as far as possible by going over them with 
 a small hand roller, the design being of course similar 
 to the large one used in the first place. After embossing, 
 the nest process is the blacking operation. This is done 
 by giving the grain side a coat of logwood decoction, 
 and subsequently another coat of levant ink, care being 
 taken to keep the flesh side as clean as possible. When 
 trimmed the kips should be well softened and grained. 
 This is now almost always done by the boarding machine, 
 
394 LEATHER MANUFACTURE. 
 
 the bulk of the work being done to the flesh side to 
 prevent piping (Fig. 71). 
 
 Seasoning and Glazing. — After this softening the 
 goods are seasoned, care being taken to have the season- 
 ing material well brushed into the grain. A suitable 
 seasoning is composed as follows : 6 pints of bullock's 
 blood ; 4 pints of logwood solution ; 2 pints of blue archil 
 solution, and \ pint of spirit of wine. When the season 
 has well dried into the leather, have the kips again well 
 grained, taking special care that the design is made as 
 perfect as possible and that " piping " is avoided. 
 
 A second seasoning is then applied composed of the 
 following ingredients : 7 pints of blood ; 4 pints of 
 logwood ; 2 pints of new milk; 1 pint of archil liquor; 
 \ pint of spirit of wine ; and 2 ozs. of burnt sugar. 
 
 After the goods have been well dried they are usually 
 fluffed on an emery wheel to clean the flesh, and are 
 then ready for glazing. It is best before taking them 
 to the machine to slightly wipe them over with a rag 
 dipped in linseed oil, as it helps to prevent dragging 
 or scratching under the pressure of the glazing-glass 
 or agate. The machines in use are many, but those of 
 the type shown in Figs. 77 and 78 are representative. 
 After glazing, the goods are again carefully grained, 
 the pattern being carefully preserved. This requires a 
 good operator, as it is impossible to rectify mistakes 
 made in this final graining. 
 
 Oiling. — A final oiling now completes the process. 
 This is applied with a suitable wad or flannel rag, the 
 oil being warmed and spread evenly over the surface 
 of the grain. Linseed or mineral oil is used for the 
 purpose, according to the quality of the goods. Some- 
 times a mixture of both is given, whilst others oil off 
 solely with the cheap mineral product. 
 
 Care should be shown in the oiling, otherwise, if too 
 much is given, it will penetrate to the flesh side, and 
 spoil the appearance of the finished leather. The kip 
 sides are now sorted into qualities and substances, and 
 are ready for the shoe manufacturer. 
 
CURRYING. 395 
 
 Currying Various Leathers. Wax Calf Skins. — From 
 an interesting series of articles upon currying which, 
 appeared some years ago in a technical journal, now 
 extinct, we make the following extracts, as they illus- 
 trate the difference between the new methods described 
 in this chapter, and the old ideas on which they are 
 based : — 
 
 " Calf skins of various weights (tanned), from 1\ lbs. to 8 
 or 9 lbs. each, are curried for shoe purposes. Light skins 
 should not be shaved so much as heavy ones ; the flesh 
 should merely be taken off and the veins taken out, so 
 that they may be level in the butt part, being first of all 
 shaved over ; they do not require flattening except they 
 are lumpy — that is, thicker in one part than another. 
 After they are shaved, scour, flesh, and grain, give them a 
 good sumacing, and let them lie for a day or two. Warm 
 the liquor before they are sleeked out of that ; stiffen them 
 a little in the shed. If they are not very coarse in the 
 grain they need not be set on the grain at all, as it will 
 be found that it renders them much softer and more after 
 the style of French skins. Before stuffing, put a little oil 
 or dubbin on the grain, turn over, and sleek them on the 
 flesh, then put the dubbin on the flesh and hang on two 
 loops in the shed to dry. When dry, take down and put 
 a little dubbin on the grain, commonly called ' tallowing,' 
 and lay them aside for a few days. Heavy skins require 
 more shaving than light ones, and therefore take more 
 dubbin. After they have lain by, if heavy skins, slightly 
 raise the grain with a toothboard or cork. Sleek the 
 grease off the flesh and grain, and whiten them with a 
 turned sleeker or knife, whichever the dresser uses best. 
 Bruise on the flesh and grain up, then wax them. The 
 process of waxing is to colour on the flesh — that is, to put 
 black on the flesh (lampblack and oil). Now glass down 
 on the flesh, and size on the same side ; hang up for the 
 size to get quite dry, then glass on the same side. 
 
 Calf Skins for Memel weigh from 30 to 40 lbs. per 
 dozen. These are shaved level, scoured flesh, and grain, 
 care being taken not to injure or break the grain ; they do 
 
396 LEATHER MANUFACTURE. 
 
 not require much sumacing, if well tanned. Sleek out on 
 the grain and hang in the shed to samm ; when stiff 
 enough, set them on the grain, and print them with a 
 memel or straight-grain roller. Oil on the grain, turn 
 over, and lay flat on the table ; but do not set them on it. 
 Stuff them on the flesh ; but they do not require so much 
 stuffing or dubbin as wax leather ; now hang up to dry. 
 Some persons have them printed after they are blacked, 
 others will not have them printed at all when dry. Next 
 take them down and black on the grain side, and size ; 
 when well hardened, slightly grain up, and put them 
 in the stove or drying-room ; when dry, clean the flesh 
 side, and finish graining, then oil with linseed oil, when 
 they are ready to cut up. 
 
 High Shoes, Black Grain. — These are mostly cut from 
 the best part of the hide, free from cuts on the grain side, 
 and must not be shaved so low at the bottom part. Scour 
 flesh and grain, compo if desired, as it renders them soft 
 and pliable, and they take more stuff; now hang in the 
 shed to samm ; set on the grain, if required, oil, and print 
 before stuffing, with a straight or cross-grained roller. 
 Turn over and stuff on the flesh side ; they will generally 
 take twice as much stuff as wax legs, in fact you cannot 
 give them too much. Now hang in the shed to dry, and 
 when dry, black on the grain and oil. When the oil is 
 absorbed, raise the print with a cork or toothboard, then 
 hang up in the drying-shed ; before doing so, however, 
 they should have a coat of dubbin on the grain, if they 
 have lain by for some time. Sleek the grease off the 
 flesh, bruise the flesh, grain up and give them a good coat 
 of clear oil on the same side : they are then fit for use. 
 
 Split Cow-Hides for Brown Bags. — These are shaved 
 lightly on the flesh side until they are level ; they are 
 then scoured, flesh and grain, and sumached ; next sleeked 
 out of the sumac ; then put into the shed to samm, and 
 when stiff enough are printed on the grain. Stiff tallow 
 dubbin is laid over the grain, buck or deer tallow being 
 preferred. Stuff on the flesh if desired, otherwise slightly 
 glass down on the flesh, and hang up to dry. After 
 
CURRYING. 
 
 397 
 
 drying, raise the print, and bruise on the flesh. See that 
 this side is free from grease, then glass the same side, and 
 brush the grain with a good hair-brush, when they are 
 ready for sale." 
 
 Blocking Boot-fronts. — This operation, which was for- 
 merly conducted by the bootmaker, sometimes forms a 
 
 Fisr. 59. 
 
 branch of the currier's business. For the following 
 description of the blocking-machine, and the method of 
 
 Fig. 60. 
 
 working it, we are indebted to Ure's " Dictionary of Arts, 
 Manufactures," &c. The leather, being dressed as before 
 described, is cut out as at a, Fig. 59, and when folded or 
 doubled, appears as at b. 
 
 In Fig. 60, 1 1 1 is a strong frame of woodwork ; 2 
 
398 LEATHER MANUFACTURE. 
 
 represents a pair of cheeks, strongly fastened in the 
 frame, and regulated to a distance by a screw. These 
 cheeks are lined with zinc. 3 is a strong plate of metal, 
 the angle at 3 corresponding exactly with the angle of 
 the cheeks ; the ends of this plate are fixed in movable 
 plates passing down the columns 1 1 ; 4 is a handle by 
 which the instrument is worked, and which, by cog- 
 wheels acting on the movable plate, brings 3 down- 
 wards. The front a is laid, after a thorough soaking in 
 water, over the cheeks 2 ; the handle being turned, 3 
 comes down upon the front, and forces it through the 
 small opening between the cheeks, and when brought out 
 below the cheeks it has the appearance given at c. 
 The plate 3, having carried the front between the cheeks, 
 
 Fig. 61. Fig. 62. 
 
 is removed (below), and the weight 5 assists in bring- 
 ing the perpendicular movable plates to their place, 
 when 3 is again put in position, and thus the operation 
 is rapidly carried on. After this the fronts are regularly 
 placed on a block, being forced into position by an instru- 
 ment called a flounder (Fig. 61), and tacked to their 
 place. After this they are slightly oiled and dried. Some 
 ingenious methods have been adopted for softening fronts 
 so as not to disturb the Hocking. They are whitened on 
 a very sloping beam or horse (Fig. 62), which enables 
 the workman to hold them better than he could on the 
 common beam. They are again blocked by the waxer, 
 and when these processes are carefully performed much 
 trouble is saved to the bootmaker. 
 
CHAPTER XXXI. 
 
 MACHINERY EMPLOYED IN LEATHER 
 MANUFACTURE. 
 
 " Stocking " or Softening Machines. — Depilation and Fleshing Plant. — 
 Machines for Crushing and Grinding Tanning Materials. — Solo 
 Leather Finishing Machinery. — Leather Dressing Machinery. — 
 Scouring and Setting Machinery. — Embossing and Softening 
 Machinery. — Tanning and Stuffing Drums. — " Boarding " and Soften- 
 ing Machines. — Machinery used in Chrome Leather Manufacture. — 
 Machinery used in the Beam House. — Finishing Machinery for 
 Chrome Work. 
 
 Duking the past few years the use of mechanical aids has 
 greatly increased in every department of the leather 
 trade. True, the British tanner is not so enthusiastic 
 over their adoption as his hustling American rival, as he 
 has to deal with smaller quantities and more varied lines 
 of goods ; in a word, he has not the opportunity of speciali- 
 sation common to the United States. On the other hand, 
 it must be admitted that many of the best machines had 
 their origin on the other side of the Atlantic, and that 
 they have only been adopted in other parts after the 
 progressive American had, by long and costly experiment, 
 proved their utility. The inventiveness of the native 
 American, and the readiness of tanners to take up new 
 ideas, have been important factors ; in short, a variety of 
 causes have favoured the transatlantic machinist, the 
 cost of skilled labour being, perhaps, amongst the most 
 important. 
 
 Of late years, however, a good deal of tanners' machinery 
 has been made in England and the Continent, and there 
 is now very little to choose in quality or price between 
 
400 LEATHER MANUFACTURE. 
 
 the various makes, although the Americans admittedly 
 do not put so great an amount of finish into their work. 
 Naturally, the greatest chance for the leather trades' 
 engineer has been in the direction of the lighter leathers, 
 and there is no doubt but that the introduction and 
 exploitation of chrome leathers has proved his great 
 opportunity. 
 
 The cost of machines suitable for sole leather tanners 
 and their enormous capacity have made it somewhat 
 difficult to successfully push this class of plant. Until 
 quite within recent times many of the sole tanneries 
 have been on a very small scale ; modern competition is, 
 however, gradually proving too strong for them, and the 
 industry is drifting into larger hands. Stronger tanning 
 materials have also taken the place of the British oak- 
 bark, and to-day there are many large tanneries in the 
 Warrington and Liverpool districts with a capacity of 
 one to three thousand hides per week. Such yards as 
 these can, of course, profitably employ machinery, and 
 the persistence of the leather trades' engineer is thus 
 slowly, but surely, having its reward. It will be im- 
 possible, in the space at our disposal, to explain or 
 enumerate all the various machines now employed in 
 light and heavy leather manufacture, but enough will 
 be said to enable the reader to become au courant with 
 the most important developments introduced within the 
 past few years. 
 
 Machinery used in Sole Leather Tanning. 
 
 " Stocking " or Softening Machines. — The old- 
 fashioned plan for softening the soaked hide was to 
 " break " it over on the half-round tanner's beam with a 
 blunt knife. This plan is still followed out in small 
 yards, and in countries where labour is cheap and 
 plentiful. This method is now supplemented or super- 
 seded by the use of the " stocks." This machine consists 
 of a metallic box, in which rise and fall two heavy 
 
MACHINERY IN LEATHER MANUFACTURE. 40I 
 
 kaniniers, raised alternately by projections in a revolving 
 wheel. The action is very effective, being a sort of 
 kneading or pounding, and the most obstinate hides give 
 way to the treatment. The duration of stocking varies 
 from ten minutes to half an hour. The ordinary form 
 of stocks in use for softening Indian kips, China, " flint," 
 and other stubborn hides is shown in Fig. 6, p. 111. 
 A more modern device, which claims some advantages, 
 
 Fig. 63. 
 
 is the American double-shover, the principle of which 
 is shown in Fig. 63. 
 
 There are other forms of stocks upon the market, but 
 the above two examples give a fairly accurate impression 
 of the main principle involved. 
 
 On the Continent of Europe a machine of a somewhat 
 different type is used, which possesses the advantage of 
 being lighter in its action upon the thinner parts of the 
 hide. The idea is simple, being that of a pair of rollers 
 pressed together by a spring. One roller is studded with 
 blunt pegs, which corresponds to grooves in the other, 
 
 2d 
 
402 LEATHER MANUFACTURE. 
 
 and so arranged that the hide is subjected to a very 
 thorough kneading. 
 
 The method of stocking and softening varies very 
 much in nearly all yards, but in spite of the march of 
 engineering improvements, the stocks remain much the 
 same in principle as in the day when the tanner probably 
 borrowed the idea from his cloth-making confrere. For 
 the lighter kind of skins, drum tumblers are effective 
 for softening ; but it will be more convenient to deal 
 with light leather machinery under a distinct heading. 
 
 ©epilation and Fleshing Plant. — After the preliminary 
 softening and cleaning, the hides intended for sole leather 
 are then ready for some process which will swell the pelt 
 and loosen the hair so that it can be easily removed. 
 The most common method is to immerse the pelt in a 
 lime solution, which not only loosens the hair and swells 
 the hide, but converts the fat it contains into a lime soap, 
 at the same time so loosening the cutaneous tissue that 
 the surplus flesh is easily worked off. Other methods of 
 unhairing depend upon the use of sulphides, and putre- 
 faction, technically termed "sweating." By whatever 
 means, however, the hair is loosened, it is usually re- 
 moved by hand, as the labour involved is not costly; 
 and so far attempts to do the work by machine — at any 
 rate on the heavier hides — have not been particularly 
 successful, owing mainly to the fact that it is generally 
 necessary to supplement the machine work by hand 
 labour, as it is often difficult to remove short hair, or 
 that from patches where the pelt has been insufficiently 
 softened. Much, however, depends upon the require- 
 ments of the market and the output of the yard. The 
 principle of many of the various unhairing machines 
 consists of a rapidly involving cylinder, fitted with 
 spiral blunt knives, working over another rubber-covered 
 cylinder, the hide being fed or introduced between the 
 two. The Turner Tanning Machinery Co., Peabody, 
 U.S.A., and Leicester, Eng., have a machine upon the 
 market large enough for sides and whole hides, which 
 is shown in Fig. 64. It is claimed by the inventors 
 
4»4 LEATHER MANUFACTURE. 
 
 of this machine that many hundreds of them are in 
 operation in the largest tanneries in all parts of the 
 world for unhairing, fleshing, and general work in the 
 beam house. The cost of big machinery is naturally 
 great, and the expenses of running fairly so ; it is there- 
 fore obvious that an appliance of this kind is only 
 profitable in large tanneries. 
 
 Much the same criticism might apply to the operation 
 of fleshing, which invariably follows unhairing. It is 
 questionable whether any machine has yet been invented 
 which will give cheaper or better results on hides than the 
 old plan of paring off the loose flesh by the use of a sharp 
 knife on the half-round beam. Machinery, it is true, does 
 the work rapidly, but a certain amount of damage is in- 
 evitable, whilst it is difficult to do the work uniformly. 
 In the case of calf, goat, and sheep skins, fleshing 
 machines are used with great success ; in fact, hand flesh- 
 ing has been displaced almost entirely in the large chrome 
 tanneries, as machine work is cheaper and more regular 
 in output. It must be remembered, however, that all sole 
 leather is invariably sold by weight, so that the intelli- 
 gence of the skilled workman is very useful, as much un- 
 necessary tissue may easily be cut away by machine, with 
 the result that the slight saving in labour may be 
 swamped in the deficient weight of the finished leather. 
 
 It is, however, only fair to add that there are several 
 large sole leather yards turning out a good mixed tan- 
 nage of sole leather which now use the fleshing machine 
 very successfully, so that it is probable it is only a 
 question of time when the old beamsman will become a 
 thing of the past. Improvements are being continually 
 introduced, and the prejudice against the use of machinery 
 passing away, whilst the unceasing competition of the times 
 naturally favours the application of any piece of plant 
 likely to cheapen a process which is of a very costly nature. 
 Machines for Crushing and Grinding Tanning Mate- 
 rials. — As this chapter does not profess to deal with the 
 technique of tanning, only as far as is necessary in 
 explaining the use of machinery, no attempt will be 
 
MACHINERY IN LEATHER MANUFACTURE. 405 
 
 made to describe the tannins in detail. Most of them, 
 however, require some preparation by machinery in the 
 way of breaking or grinding by means of bark mills or 
 disintegrators. The object is to grind the material so 
 that the liquor has ready access to the interior cellular 
 tissue, in which most of the tannin is found. The bark 
 mill in general use consists of a toothed cone working 
 inside another similarly constructed cone, arranged much 
 on the same principle as a coffee mill. A preparatory 
 breaking by a special machine is also necessary where the 
 bark to be ground is in long strips, and this is usually 
 done by means of toothed breakers. A common form of 
 mill is constructed by the well-known Exeter firm of 
 Huxham and Browns, and B. and D. Wright, Leeds. An 
 improved bark cutter is made by the Turner Machine 
 Co., Peabody, United States, and is durable, simple, 
 and effective ; and it is claimed by the inventors that it 
 will prepare forty cords of bark per day for the leaches. 
 
 Such materials as valonia and myrobalans are usually 
 broken by means of the machines known as disintegrators, 
 such as are used to pulverize bones, &c. The principle 
 is simple, and depends upon knocking the material to 
 powder by the action of rapidly revolving beaters, which 
 in some cases are driven at a speed of between 2,000 and 
 3,000 revolutions a minute. This class of machinery is 
 very effective, but the consumption of power is rather 
 great, whilst the fine dust is apt to prove troublesome. 
 For some purposes myrobalans are only required roughly 
 crushed by the tanner. In this case a machine with, 
 fluted or toothed rollers is more useful than a disinte- 
 grator, as less power is required and the proportions of 
 dust is very little. Yalonia — a species of large acorn cup 
 from Southern Europe — may also be satisfactorily crushed 
 by this class of machinery. The most common form of 
 disintegrator is shown in Fig. 65. 
 
 Many other varieties of devices for preparing tanning 
 materials are also in vogue, but the examples mentioned 
 fairly represent the general principle on which most of 
 them are constructed. In England machinery is not 
 
406 
 
 LEATHER MANUFACTURE. 
 
 much favoured for carrying tanning material to the 
 leaches or extraction pits, but in America "conveyors" 
 of various kinds are freely used. These consist often 
 of endless iron chains carrying wooden cross-bars at 
 intervals, working along suitably constructed spouts. 
 As the use of conveyors is only profitable in large 
 tanneries where labour is dear, and, furthermore, their 
 
 Fig-. 65. 
 
 design has already been explained on p. 161, it would 
 serve no useful purpose to here further enlarge upon 
 them. 
 
 Sole Leather Finishing Machinery. — Sole butts after 
 tanning are usually drained of surplus Hquor, and then 
 are given a coat of oil on the grain side and allowed to 
 partially dry, and are then " struck " or " pinned " out. 
 The object is to stretch and render the grain even, and 
 often to scour out as much bloom — a whitish deposit left 
 in by tanning — as may be desirable to suit the require- 
 ments of the market. Many tanners of best quality oak- 
 bark leather still persist in doing this by hand, using a 
 
MACHINERY IN LEATHER MANUFACTURE. 407 
 
 triangular tool called a pin, and thoroughly extending 
 the leather over a horizontal beam or " horse." 
 
 Of late years, however, machinery has been successfully 
 introduced for the purpose, and nearly all the biggest 
 English yards employ various types of machines for 
 striking. The most popular form of machine for striking 
 offal is that invented by Priestman some years ago, 
 the principle of which remains the same, although im- 
 provements have been added from time to time. A 
 common form of this appliance is shown in Fig. 20, 
 p. 165. 
 
 The "principle is simple, and consists of a revolving 
 cylinder, to which are attached V-shaped blunt brass 
 knives, under which the leather is fed. The pressure is 
 regulated by a foot-lever acting on a movable bed. The 
 amount of work turned off by this machine is very great, 
 but it is not very well adapted for irregular-shaped pieces 
 of leather, such as bellies, &c. 
 
 Many tanners now use the striking machine for butts 
 invented by Wilson (Fig. 66), which is perhaps as near an 
 approach to hand labour as can be obtained. The leather 
 is carried over a revolving drum, and the grain is operated 
 upon by blunt knives working outwards from the centre. 
 Where it is necessary to remove the bloom, slabs of stock 
 stone are substituted for the knives. This piece of plant 
 has been running for many years in some yards and has 
 proved a valuable help, as the cost of striking is nothing 
 like so great as hand labour. It is, however, more es- 
 pecially useful to large tanners, as the first cost is fairly 
 high, and it requires a firm foundation, the oscillating 
 motion being rather pronounced. A modification of this 
 type of machine is also now freely used for pinning offal. 
 
 Sole leather, after lightly oiling and drying, is then 
 submitted to a rolling operation to give it the necessary 
 solidity and firmness. On the Continent a different 
 method prevails, and the leather is well hammered by a 
 machine known as the Marteau-a-battre, the action being 
 much the same as that of the well-known steam 
 hammer. 
 
MACHINERY IN LEATHER MANUFACTURE. 409 
 
 The old type of rolling machine consisted simply of a 
 loaded box, to which was attached a brass roller. This 
 was dragged over the butts, which were spread out upon 
 a plank or zinc bed, and, although slow and cumbrous, 
 the method is still regarded as the perfection of leather 
 rolling. Fig. 22, p. 166, shows a form of spring butt 
 roller by Huxham and Browns in which the necessary 
 pressure is obtained from springs placed above the roller, 
 which runs alternately backward and forward over a flat 
 table beneath a fixed girder. The pendulum roller, 
 Fig. 23, p. 167, is especially suited for sides, such as East 
 India kips or Singapore leather, in which great firmness 
 and a high gloss is necessary. The roller being narrow 
 lends itself readily to the inequalities of substance, and its 
 construction is very convenient to the manipulation of 
 the irregular belly and shank portion of the side under 
 treatment. Its oscillating motion causes much vibration 
 and noise, so that it is best fixed wherever possible on 
 the ground floor. It is, however, cheap, easy to make 
 and repair, and well adapted to special classes of work such 
 as are mentioned above. 
 
 A familiar and useful type of machine is the " C " 
 roller, in which the leather is passed between two brass 
 covered rollers. Practically any pressure may be 
 obtained by a weighted lever attached to the top roller, 
 but experience has shown that this type is unsuitable to 
 butts, as it destroys the flat appearance, or — to use a 
 technical expression — makes them " baggy." For bellies, 
 shoulders, and splits this variety of machine is very 
 suitable, as the cost of manipulation is not great by 
 reason of the quantity of work done, whilst a simple 
 reversible motion, obtained by using a crossed and open 
 belt, obviates, to a large extent, any jumping of the 
 rollers when narrow pieces of leather are under treatment. 
 It may be added that nearly in all cases leather is rolled 
 twice, the two operations being designated " rolling on " 
 and " rolling off." After complete drying, sole leather 
 is ready for the market,, although in some cases colouring 
 composition are applied to the grain side, and a final 
 
4 io LEATHER MANUFACTURE. 
 
 brushing — which is now often done with a machine — 
 given to bring up an attractive-looking gloss. 
 
 Leather Dressing Machinery. — The mechanical ap- 
 pliances employed under this heading are extremely 
 numerous and ingenious, and, since the introduction of 
 the chrome tannage, have been greatly augmented, 
 although it must not be assumed that some of the 
 machines mentioned here are not both used on chrome 
 and other forms of leather making. 
 
 The term " dressing leather " is fairly comprehensive, 
 and embraces harness, saddlery, mechanical, accoutre- 
 ment, boot and bookbinding leathers, &c. Each of these 
 branches of the leather industry is often a special business, 
 but there are certain types of machines fairly common to 
 all. 
 
 As most tanned leather is rough and uneven when it 
 leaves the hands of the tanner for the currier, it is there- 
 fore necessary to equalize the substance in some measure. 
 For harness and belting leather it is only usual to remove 
 the loose flesh and the marked inequalities of the butt, 
 but for such purposes as shoe leather, which depend upon 
 a flesh side finish, this preliminary operation is very com- 
 plete, and is technically known as shaving, an operation 
 requiring a long training and a high pitch of perfection. 
 Within recent years this process, which is done by 
 laboriously paring the hide or skin with a suitable knife 
 over an inclined " beam " or block of lignum vitce 
 (Fig. 58, p. 371), has been successfully attempted by 
 machine (Fig. 67) ; in fact, by far the greater part of 
 chrome tanned leather is now shaved in this way. 
 Chrome leather, mainly on account of the looseness of 
 its texture, is difficult to shave by hand, whilst the 
 cost on goat skins makes it almost prohibitive. The 
 principle of the shaving machine depends upon passing 
 the damp leather under a rapidly revolving cylinder, 
 to which is attached a series of steel knives, kept auto- 
 matically sharpened by emery wheels. The leather 
 is pushed up to the knives by a foot-lever actuating a 
 rubber roller, and by a screw arrangement the distance 
 
MACHINERY IN LEATHER MANUFACTURE. 
 
 411 
 
 between the cutting and cushion cylinders may be 
 regulated to suit the requirements of the operator. This 
 piece of currier's plant is one of the most ingenious yet 
 introduced, and is fast superseding hand labour on the 
 lightest classes of goods. It is, however, yet capable of 
 improvement, as it is rather dangerous to the operator, 
 and somewhat deficient in reducing power on a close, 
 firm texture, whilst the flying emery and steel dust is apt 
 to stain ordinary vegetable tanned leather. 
 
 In practice both untanned and tanned hides are often 
 divided into two or more portions by machine. The 
 principle employed in splitting " green " hides and skins 
 consists in passing the swollen and limey pelt over a 
 wooden drum, whilst the division is made by the action 
 of a rapidly vibrating knife. Attempts have been made 
 to do green splitting by means of the band-knife machine 
 (see Tig. 68), with a fair measure of success, and there 
 seems no real reason why the difficulties should not be 
 conquered with a little determined ingenuity 
 
412 
 
 LEATHER MANUFACTURE. 
 
 Tanned leather is now almost universally split on the 
 band-knife machine before mentioned. As the name 
 implies, the cutting is done by means of an endless steel 
 belt, which travels over two large pulleys, the edge being 
 kept sharp by the automatic grinding of emery wheels 
 below the machine. The machine is rather complicated 
 and fairly expensive, but remarkably useful. The damp 
 leather is fed between brass rollers to the knife's edge, 
 the inequalities being provided for in the under roller by 
 
 Fig. 68. 
 
 small eccentric brass sections, which in turn press upon a 
 resilient rubber cylinder. This machine is capable of 
 getting through an enormous quantity of work, but 
 requires the services of a skilled and intelligent operator 
 to secure good results. Butts for army upper and 
 kindred purposes are split on an older form of machine 
 known as the " Union " (Fig. 54, p. 322), the leather 
 being pressed down and drawn over a fixed knife. For 
 work of this class this machine has some advantages, as 
 the split leather is more even in substance. 
 
MACHINERY IN LEATHER MANUFACTURE. 413 
 
 Scouring and Setting Machinery. — During the pro- 
 cess of tanning by immersion in bark liquors, &c, the 
 grain side of the leather, as already stated, becomes more 
 or less filled with a whitish deposit called " bloom," 
 known to chemists as ellagic acid. In most cases it is 
 necessary to remove this, as it interferes with subsequent 
 operations. The principle of the scouring machines is 
 much the same as that followed out in sole-leather 
 "pinning," where, indeed, the object aimed at is almost 
 identical. As a matter of fact, it is usually only the 
 heavier classes of upper belting and harness leather 
 
 Fig. G9. 
 
 which are scoured by mechanical aid, and for this purpose 
 a machine of the type illustrated in Fig. 69 is used to some 
 extent in England. The leather is spread in a wet con- 
 dition on a movable table, and is subjected to the action 
 of a reciprocating head, which has a most ingenious 
 motion. The amount of work these appliances get 
 through is very great ; but the first cost is heavy, and, 
 in consequence, they have to be fairly fully employed to 
 be profitable. 
 
 An older type of machine, known as the "Bourdon 
 Scourer," is shown at Fig. 17, p. 156. In this case the 
 
414 LEATHER MANUFACTURE. 
 
 wet leather is passed under a cylinder into which are 
 fixed projecting slabs of stone, which revolve at a high 
 rate of speed, the leather of course being pressed up to 
 the revolving working part by means of foot-levers 
 actuating a suitable cushion. This machine is suitable 
 for heavy leathers for military purposes, &c, but is little 
 used for the finer classes of manufacture. 
 
 Leather is, after drum-stuffing, extended or " set " to 
 eliminate the stretch and to give it pattern, and then 
 dried. The same operation is necessary for chrome 
 tanned leather after milling in fat-liquor, which is 
 simply a weak emulsion of soap and oil modified to 
 suit the particular method of leather manufacture. As 
 the labour involved in setting is rather excessive, but 
 purely mechanical, machinery has been introduced with 
 great success in recent years. For belting leather the 
 type shown at Fig. 69 is also used for this purpose, but 
 there is no standard machine used by upper-leather 
 manufacturers for setting, although many machines are 
 capable of doing good work at a low cost where the shape 
 of the leather is fairly regular. 
 
 Embossing and Softening Machines. — Certain leathers 
 for shoe, upholstery, bag, and fancy purposes are often 
 printed or embossed to imitate the natural marking of 
 some other skin ; thus sheep skin or basil is frequently 
 stamped with a design to imitate morocco or alligator 
 hide, whilst cow-hide, and even the flesh split, is 
 embossed and finished to imitate the well-known marking 
 of pigskin for legging purposes. Levant and memel 
 leather for common and heavy boots are embossed with 
 popular patterns, termed "star," "pebble," &c, and 
 thousands of Bombay -tanned kips are stamped with 
 a long barley-shaped grain and sold as cow-hide. All 
 the smaller skins are embossed by passing them in a 
 damp condition beneath an engraved roller. The more 
 simple designs are cut by hand on iron or copper rolls, 
 the more elaborate being electrotyped, whilst floral and 
 artistic designs are impressed by submitting the leather 
 to pressure under a prepared plate. The ordinary form 
 
MACHINERY IN LEATHER MANUFACTURE. 415 
 
 of embossing machine is shown at Fig. 81, p. 432. The 
 embossing roller is now made in the shape of a hollow 
 cylinder, and is thus easily removed from the working 
 spindle. The most common size in use is the 4 ft. 6 in. 
 machine, which takes the kip side or sheep skin quite 
 easily. The smaller machines with 5-in. or 6-in. rollers 
 are now seldom used, as the larger machine turns out 
 the work faster and better. 
 
 Tanning and Stuffing Drums or Tumblers. — As drum- 
 tumblers are used by the tanner and light' leather manu- 
 facturer very freely, it will be perhaps necessary to say 
 a few werds on them here, although these machines have 
 been to some extent dealt with in the chapter on Kip- 
 Leather Currying. The form of tumbler illustrated in 
 Fig. 70, p. 416, gives a fair idea of its construction and 
 form ; but it will be seen from the design which appears 
 here that the drum is capable of many modifications. 
 Some users prefer the door in the side as shown in Fig. 
 70, whilst others insist upon having the opening in 
 the centre. The latter style has the advantage that 
 the drum may be swung upon an axle, and this is a 
 decided help when power and vibration are considerations. 
 Some makes of tumblers are fitted with pegs standing 
 up in the interior ; others, again, possess shelves. A 
 good deal depends upon the class of work required, or 
 the individual fancy; but as the experience of expert 
 engineers is always available, it is not necessary to take 
 up valuable space by going very fully into these points. 
 It is important, however, to note that a tanner's tumbler 
 should be strongly built of the best seasoned timber, and 
 that all exposed iron work is covered with some material 
 which does not corrode by the action of the tannic acid ; 
 otherwise stained and spoilt leather is a certain result. 
 These drums are also used for tanning proper, bateing, 
 washing, &c, by the upper leather tanner, whilst the 
 manufacturer of the lighter leathers finds them indis- 
 pensable for re-tanning, sumacing, dyeing, stuffing, 
 and a host of other purposes which will readily occur 
 to the reader. In chrome tanning, too, the drum is 
 
4i6 
 
 LEATHER MANUFACTURE. 
 
 wanted in many ways, so that simple though this piece 
 of tanning plant may be, yet it is important enough 
 to warrant the attention of the leather trades' engineer, 
 who has succeeded in improving it in many ways during 
 the past few years. The improved form of stuffing-drum 
 shown in Fig. 70 is fitted with an apparatus for intro- 
 ducing the melted greases and hot air. 
 
 Fig. 70. 
 
 "Boarding" and Softening Machines. — Many forms 
 of leather have to be softened by mechanical means, and 
 various methods are employed to do this, according to the 
 characteristics required. The old-fashioned tool, which 
 is still used to a large extent, consisted of a suitably 
 covered pommel, which was attached to the hand or arm 
 under which the leather was rubbed. This has the dual 
 effect of softening the leather and bringing up the 
 
MACHINERY IN LEATHER MANUFACTURE. 417 
 
 familiar pattern of the marking of the grain. The 
 softening of levant shoe leathers is now done extensively 
 by machinery, and for the rougher part of the work it 
 has completely displaced the hand process. A common 
 type of softening machine is shown at Fig. 71. In 
 mineral tannages, such as alum and salt, or chrome, the 
 softening or stretching of the fibre is an expensive 
 business, and special machines, described in the section 
 dealing with Chrome Leather Machinery, are freely used. 
 The final operation necessary to the finishing of most 
 upper leathers which are dressed with grease, and which 
 
 Fig. 71. 
 
 is termed whitening, is now often done by machine. 
 The operation, including that of " buffing " the grain 
 side, is done to some extent by an ingenious revolving 
 cylinder of knives, which is given a sort of reciprocating 
 motion. Attempts to use it have only been partially 
 successful in England, mainly because the shoe manu- 
 facturer demands a very fine " face," or density of fibre, 
 which is not easily obtained by machine, so that in some 
 cases this final operation is carried out by cutting the 
 surface of the leather by sharp turned edges of a tem- 
 pered steel plate on an absolutely level surface. The 
 
 2 E 
 
4i8 
 
 LEATHER MANUFACTURE. 
 
 whitening machine in use in America, and to a limited 
 extent in England, is shown in Fig. 72. 
 
 Fig. 72. 
 
 Minor operations in leather manufacture, such as 
 blacking, glassing, brushing, fluffing, &c, are, of course, 
 
MACHINERY IN LEATHER MANUFACTURE. 419 
 
 often executed by machinery ; but the design of these 
 mechanical aids is simple, and their use so well under- 
 stood that no space need be taken up with their 
 description. 
 
 Machinery used in Chrome Leather Manufacture. 
 
 The rapid development of this branch of leather manu- 
 facture by America has given an impetus to the use of 
 machinery that was little anticipated. The necessity for 
 keeping the work going in an unbroken stream has 
 doubtless had much to do with this, whilst declining 
 profits and the high rate of wages paid for certain opera- 
 tions have all favoured the engineer. The enormous 
 quantities of skins turned out by some of the great 
 Philadelphia houses are almost beyond belief, as several 
 calculate their output at from two to three thousand 
 dozen glazed goat skins per day. It will be seen, there- 
 fore, that the difficulty of finding and controlling labour 
 for such a trade is very great, and that the business has 
 been built up largely by the co-operation of the engineer 
 with the practical tanner. 
 
 Machinery used in the Beam House. — It is now 
 possible to do almost every operation in what is known 
 as the " wet work " by machine, and a brief summary of 
 the machines usually employed may be useful as showing 
 how independent the large American or European tanner 
 is of skilled labour. Taking Patna dried goat skins as 
 an example : these are usually well soaked in plenty of 
 clean water, to which a little borax may be added with 
 advantage, and are often mechanically softened by 
 " stocking " or drumming for twenty minutes or so. In 
 small yards the work is done by hand by " breaking " 
 over the tanner's beam with a blunt knife. 
 
 The next step is to plump the skins and loosen the 
 hair, which is done by immersing them in a solution of 
 lime and arsenic sulphide. Unhairing is a cheap opera- 
 tion, but takes room, so that the use of machines has 
 
420 
 
 LEATHER MANUFACTURE. 
 
 been introduced with success, and as the same type of 
 machine is used later on in the manufacture of chrome 
 leather, the illustration at Fig. 73 may be studied with 
 advantage. The skins are simply spread in a folded 
 condition on each side of the vertical table, which by an 
 ingenious motion passes between two revolving rollers, 
 
 Fig. 73. 
 
 both of which are fitted with blunt knives, and revolve 
 in different directions. The dehairing is not done very 
 clean, but what remains is easily disposed of in a subse- 
 quent process. Other types of machines are also favoured 
 for unhairing, and an enormous amount of work can be 
 done on a modified form of the machine shown for sole 
 leather at Fig. 64 (p. 403), whilst there are others equally 
 
MACHINERY IN LEATHER MANUFACTURE. 421 
 
 good upon the market — such as that shown at Fig. 74. 
 The one drawback to the use of machines for this purpose 
 is the rather large proportion of damage done to imperfect 
 stock. 
 
 After unhairing the goat skins are usually fleshed. 
 This process, being a skilled and expensive one, is now 
 generally executed by a machine, the principle of which 
 
 Fig. 74. 
 
 is much the same as that shown in Fig. 64 (p. 403) or 
 Fig. 74, made by the Turner Co., Peabody, U.S.A. The 
 limey and swollen skins are spread on a rubber-covered 
 roller, and are passed under a cylinder fitted with knives, 
 which are so arranged as to spread the skin outwards 
 from the centre. It is as well to remember that very 
 imperfect skins are best done by hand, as the rapid 
 action of the machine makes it impossible to guard 
 against further damage. 
 
422 LEATHER MANUFACTURE. 
 
 Passing on to deliming, or "puring," as it is techni- 
 cally called, it is useful to note that, even here, mechanical 
 aid is necessary. Instead of the old-fashioned plan of 
 immersing the skins in tubs containing the puring 
 solutions, they are now almost always kept on the move 
 by agitation in paddle tanks. The time of this very 
 disagreeable operation is thereby considerably shortened, 
 and the danger of damage to the goods reduced to a 
 minimum. After the pure has " brought the skins down," 
 i.e. reduced the plumpness caused by the lime, &c, a 
 further working called " scudding " is necessary to expel 
 the short hair, hair cells, pigment, and lime, soap, fat, 
 &c, otherwise the resultant leather would be an inferior 
 quality. 
 
 This operation is, in most progressive yards, now done 
 by machine, the skin passing over a rubber-covered 
 cylinder, whilst slate tools projecting from an upper 
 cylinder more or less thoroughly cleanse the grain from 
 impurities which, if not removed, would seriously inter- 
 fere with the beautiful glazed appearance of the finished 
 leather. As scudding is also done on much the same 
 class of machine as that for fleshing — in fact, the same 
 machine is often used with the insertion of a special 
 roller — it is not necessary to illustrate this appliance. 
 Goat skins for chrome leather are after scudding thoroughly 
 washed in plenty of water and passed on to the actual 
 tanning operation. As already explained, this consists of 
 immersing the pelts in a solution of bichromate of potash 
 and hydrochloric acid for a few hours, and then trans- 
 ferring them to a reducing bath of hyposulphite of soda 
 and hydrochloric acid. This is followed up by a washing 
 in borax or some other alkali to neutralise the acid 
 present. The actual tanning is carried out in the paddle 
 vat or tumbler — generally the former — already described, 
 and the skins after the bichromate bath are struck out 
 by a machine of the type shown in Fig. 73. The subse- 
 quent processes of " fat-liquoring " and dyeing are 
 ordinary operations, and require no special comment in 
 a section which only professes to touch on the technique 
 
MACHINERY IN LEATHER MANUFACTURE. 423 
 
 of the chrome process, as far as it is necessary to elucidate 
 the working of mechanical appliances. The striking-out 
 operation referred to above is repeated several times as 
 required, the final " setting " or permanent extension 
 being also given on the same machine. The operation 
 is quite simple, the skin being folded down the back 
 upon a vertical table which rises between two spiral 
 knife-covered rotating cylinders. The effect is to 
 thoroughly stretch the skin and to make the desirable 
 fine grain. It is easy to use, one man and a boy being 
 ample to attend to it, whilst the quantity of work got 
 through is very great. Chrome leather shaving is now 
 carried out on the machine shown in Fig. 67 (p. 411) ; 
 results have proved that chrome leather is absolutely un- 
 fitted to hand labour, as the leather is exceedingly difficult 
 to cut in any stage, and especially so in the "blue" 
 condition, i.e. after the reducing bath. The lighter kinds 
 of goat skins cost very little indeed to shave by machine, 
 as they are fairly level, and only need reducing towards 
 the head of the skin, whilst plenty require no more than 
 a slight stroke to level them sufficiently to meet the 
 market requirements. 
 
 Finishing Machinery for Chrome Work. — Most of 
 the operations in the " dry work " are, in all the large 
 manufactories, now executed by machine, as the cost is 
 not to be compared with hand labour. The appliances 
 used are mainly for softening and polishing, and as each 
 skin has to undergo these operations several times, the 
 cost even with machinery is fairly great. The dyed 
 goat skin is, as we have already shown, after fat- 
 liquoring, dyed, "struck," and set out, given a coat 
 of glycerine and neatsfoot oil and dried at a high 
 temperature. The leather at this stage is hard and 
 "tinny," and requires plenty of mechanical work to 
 bring it to a saleable condition. After cooling down 
 and storing, the skins are usually damped back by 
 placing them in damp sawdust for a few hours, and are 
 then staked or softened by machinery. In the early 
 days of chrome leather manufacture, this process was 
 
MACHINERY IN LEATHER MANUFACTURE. 
 
 425 
 
 done by drawing the damp skin over a steel plate fixed 
 into a wooden post, the knee being the main source of 
 power, whilst the hands were used to guide and mani- 
 pulate the skin. Another plan was to attach the skin 
 to an upright " perch," and, by means of a short crutch, 
 which had a steel plate at its extremity, the leather was 
 extended in every direction. These crude methods are 
 now gradually becoming obsolete, and the machine shown 
 
 Fig. 76. 
 
 in Fig. 75 is one of the best tools for the purpose. The 
 action is very simple, the leather being pulled between 
 two steel plates; the opening and closing motions of 
 the jaws of the machine are quite novelties in leather 
 appliances, and are, in fact, somewhat startling to a 
 beginner. As the operator has to take the entire " pull " 
 of the machine by the pressure of his body to the leather, 
 it is well to put a fairly strong man to work it, otherwise 
 accidents might occur, or, at least, imperfect skins get 
 
426 
 
 LEATHER MANUFACTURE. 
 
 hopelessly damaged. There are, of course, other staking 
 machines on the market, but the principle is much the 
 same. The skins are staked twice, or even three times, 
 according to requirements, and are usually glazed after 
 each staking. The foundation for the glaze, consisting 
 of a weak solution of blood albumen, is usually applied 
 with a soft pad to the grain side of the skin, and partially 
 or wholly dried before passing on to the machine. The 
 
 Fig. 77. 
 
 flesh side, too, is often " fluffed," i.e. abraded on a wheel, 
 much on the principle of the grindstone, with the 
 difference that fairly coarse emery powder is the abrasive 
 medium. The wheel is of iron, and is shod with a stout 
 wooden tyre slightly rounded off, this forming the bed 
 for the emery. The dust from the operation is very 
 troublesome, but is removed to a large extent by well- 
 arranged fans, which draw it away from the operator to 
 
MACHINERY IN LEATHER MANUFACTURE. 
 
 427 
 
 a suitably placed receptacle. A familiar type of this 
 machine is shown at Fig. 76. 
 
 The final operation of glazing is certainly one of the 
 most important in the manufacture of chrome kid, and 
 involves a great amount of technical skill. The staking 
 
 Fig. 78. 
 
 has had the effect of disturbing the " lay " or pattern of 
 the skin, and unless the manipulation is almost perfect, 
 the damage done by the rapid action of the polishing 
 tool is apt to be very great. Types of machines used are 
 
428 
 
 LEATHER MANUFACTURE. 
 
 shown at Figs. 77 and 78. These are more generally used 
 for glazing vegetable tanned leather, whilst Fig. 79 has 
 some special points of excellence, which make it specially- 
 suitable for polishing light chrome stock. For goat, 
 however, a spring head is used. The frames may be 
 either of wood or iron, but the former is claimed to give 
 a greater resiliency, which has a beneficial effect on light 
 
 Fig. 79. 
 
 and thin stock. Keference to the illustrations will 
 show that the working arm carries a small cylinder of 
 glass or agate, which strikes the extended skin with a 
 rapid downward motion. The rate of speed varies, 
 according to the work and the fancy of the operator, 
 from 80 to 120 strokes per minute. The oscillating 
 motion caused by this class of machine is great, and 
 
MACHINERY IN LEATHER MANUFACTURE. 
 
 429 
 
 it should be very firmly fixed, both from above and 
 below, if good results are to be obtained, otherwise 
 the damage from broken skins and glazing glasses 
 is apt to prove rather an expensive item. Probably 
 users of this machine would, under any circumstances, 
 do well to remember that it is a costly business to 
 
 Fig. 80. 
 
 train operatives for this process, so that only the most 
 intelligent men should be selected. 
 
 Before concluding this article on the mechanical 
 appliances used in chrome leather manufacture, it may 
 be mentioned that a measuring machine has now become 
 an indispensable adjunct to a works of any size (Fig. 80) ; 
 this is in America and Europe the recognised standard 
 for leather-measuring between buyer and seller. The 
 skin, in travelling through the machine, affects the 
 measuring segments arranged close together, which in 
 turn are registered on an index, carefully noted by the 
 operator, and marked on the skin. This machine is very 
 ingenious, and soon pays for the cost of the outlay as 
 every inch of the leather is calculated ; and as all 
 
430 LEATHER MANUFACTURE. 
 
 chrome leathers are sold by surface measurement, it will 
 be seen that it is an absolute necessity that this end of 
 the business should be well looked after. 
 
 The most recent idea for measuring the superficial area 
 of leather is, however, Connolly's Areameter. The instru- 
 ment is simplicity itself, and broadly consists of a set of 
 geared wheels, to which are attached a convenient arm 
 carrying a pointer. This latter is passed around the edge 
 of the skin to be measured, and the result read off on a 
 dial attached to the central part of the machine. After 
 exhaustive tests, made by Dr. Glazebrook of the National 
 and Physical Laboratory, the Areameter has been recog- 
 nised as an official standard by the Board of Trade ; and 
 at a recent meeting of the Leather Trade Section of the 
 London Chamber of Commerce it was recommended to 
 the trade " for verifying the measurement of leather and 
 skins, and as a means of determining disputes between 
 buyer and seller." The machine is put on the market 
 by Connolly's Areameter Company, Brighton Chambers, 
 Denman Street, London Bridge, London, S.E., and is 
 made in various sizes to suit the convenience of users. 
 
 In bringing this article to a close, it may be said that 
 no attempt has been made to go fully into the technical 
 details of leather manufacture ; the idea has been simply 
 to give just a few practical hints to readers who may 
 not be familiar with the class of machines mentioned. 
 Further particulars relating to the chrome process have 
 already been given in another chapter. 
 
CHAPTER XXXII. 
 EMBOSSING LEATHEB. 
 
 Copying Crocodile, Alligator, &c, Skins. 
 
 The art of embossing and otherwise ornamenting leather 
 dates back from a very early period, the Egyptians 
 having practised the art nearly three thousand years ago. 
 At a much later date, namely, about the thirteenth cen- 
 tury, the art appears to have been extensively practised 
 not only in Italy and Spain, but also in England, many 
 specimens of which are still extant. 
 
 The more modern applications of embossed leather have 
 been chiefly devoted to leather employed in bookbinding, 
 furniture, bags and reticules, purses, and other fancy 
 articles ; while still more recently — with the aid of the 
 electrotype process — moulds of reptile skins, as those of 
 the crocodile, alligator, &c, have been taken, by means of 
 which excellent imitations of the natural skins have been 
 produced, possessing all the beauty of the original skins 
 at a lower cost to the purchaser. 
 
 Embossing machines are made by the following firms 
 of engineers : Messrs. Joseph Hall & Co., T. Haley & Co., 
 B. and D. Wright, Leeds, and Messrs. Farrar & Young, 
 Bramley. The Moenus Machine Co., Frankfort-on-Main, 
 also make embossing machines, their latest design, " The 
 Altura," being one of the most successful pieces of plant 
 ever put on the market for leather work. Messrs. Huxham 
 & Brown, of Exeter, have also lately introduced a special 
 kind of machine for the purpose, and the writer has seen 
 excellent work done by it in a very rapid and effective 
 manner. 
 
432 
 
 LEATHER MANUFACTURE. 
 
 Copying Crocodile, Alligator, &c, Skins by Electro- 
 type — It will be readily understood that by the electro- 
 type process perfect impressions of the skins of the 
 crocodile, alligator, boa - constrictor, and other reptile 
 skins can be obtained, and from the copper moulds thus 
 
 Fig. 81. 
 
 produced, leather, previously damped with water, can be 
 impressed, and exact copies of the original obtained to an 
 unlimited extent. By the same process morocco, seal, and 
 other skins are reproduced, and form an extensive and 
 greatly increasing branch of leather manufacture, some of 
 
 Fig. 82. 
 
 the results obtained being exceedingly beautiful, the finest 
 markings of the grain being reproduced with perfect 
 fidelity. Electrotyped copper rollers and plates, bearing 
 the pattern of real skins, can now be obtained for the 
 manufacture of almost any variety of imitation leather, 
 and from each roller several thousand copies may be 
 
EMBOSSING LEATHER. 
 
 433 
 
 produced. In Fig. 81 is shown the ordinary form of 
 embossing and printing machine made by the above- 
 named firms, and in Fig. 82 is represented an electrotyped 
 copper roller. Small hand-presses are made by the same 
 
 Fig-. 83. 
 
 firms for printing from electrotype plates of real skins up 
 to 22 inches by 27 inches, the embossing machine being 
 employed for larger surfaces. An illustration of one of 
 these hand machiues is shown in Fig. 83. 
 
 2? 
 
CHAPTER XXXIII. 
 FELLMONGERING. 
 
 Classification of Sheep Skins. — Treatment of the Skins. 
 
 Although fettmongering, or removing the wool from sheep 
 and lamb skins, is a distinct and separate trade, more 
 especially in London, the art is sometimes combined with 
 the other operations of the light leather manufacturer in 
 some parts of the country, and therefore a brief descrip- 
 tion of the method of treating sheep skins by the fell- 
 monger will, it is hoped, be useful. Indeed, even if not 
 practised by the skinner or manufacturer of light leather, 
 he should at all events be conversant with the method 
 adopted to free the skins from wool before they come into 
 his hands, since this will enable him to judge from the 
 appearance of the pelts whether the process has been pro- 
 perly conducted or clumsily and carelessly performed ; and 
 it is well known that fellmongered skins have frequently 
 exhibited unmistakable signs of careless and injudicious 
 treatment. Sometimes the skins have been piled in heaps 
 to make them sweat, producing incipient putrefaction, by 
 which the workman's labour in removing the wool was 
 rendered easier ; but the effect of this is that much of the 
 substance of the skin is rendered soluble, even in cold 
 water, and consequently the skins suffer loss in weight 
 when passed through weak lime liquors. 
 
 The London fellmongers, who conduct their business 
 upon a very extensive scale, and with every possible care, 
 have a high reputation for the excellence of their sheep 
 pelts; the same may be said of many of the provincial 
 
FELLMONGERING. 435 
 
 fellmongers, who know the importance of having their 
 workmen well supervised when conducting operations re- 
 quiring skill and judgment. 
 
 Classification of Sheep Skins. — The skins of sheep 
 slaughtered in Great Britain are divided into large, medium, 
 and small skins, and may be arranged under the following 
 heads : 1, Lincoln, Leicester, Cotswolds, and other large 
 kinds weighing from 9 st. and upwards ; 2, Southdowns, 
 Scotch, and other skins of medium weight ; and 3, Skins 
 of small Welsh mountain sheep, foreign sheep slaughtered 
 in this,, countrjr, and the numerous varieties of lamb skins. 
 
 The larger stout sheep skins are usually split by machi- 
 nery, the grain side being used for skiver, and the Jlesh 
 side employed in preparing buff or " shamoy " leather 
 (oiled leather), and in the manufacture of parchment. A 
 considerable number of the larger heavy sheep skins are 
 tanned into what are called basils, the West of England 
 being specially famous for its oak-tanned basils, while 
 Scotland and some of our northern counties also produce 
 vast quantities of basils, which are tanned with larch bark, 
 and are much used by saddlers for lining the heavier 
 leathers. It is believed that the aromatic odour imparted 
 by larch bark gives to the leather prepared with it similar 
 attributes to those generally accorded to Russian leather. 
 Considerable numbers of the larger sheep skins are taived 
 with alum and salt. 
 
 The medium weight skins are chiefly tanned with sumach 
 for roans, a variety of leather somewhat resembling mo- 
 rocco, but wanting its peculiar grain. These skins are 
 also used for preparing leather used for the rollers of cotton 
 spinning machinery. The small sheep skins of Wales and 
 Scotland and the mountainous districts of England are 
 employed in the art of tawing, for gloves, shoe linings, and 
 numerous other purposes. Cape sheep and lamb skins are 
 very extensively used by the manufacturer of light leather, 
 being nearly equal to goat skins, and the leather prepared 
 from them is largely used for making dog-skin gloves, and 
 many kinds of coloured gloves exposed for sale as kid gloves. 
 
 Treatment of the Skins.— The skins are first thoroughly 
 
436 LEATHER MANUFACTURE. 
 
 washed in water, to cleanse them from filth and dirt, after 
 which they are spread out flat, one above another, with the 
 flesh side upward. Each skin is then painted over with a thick 
 cream of lime on the flesh side. The skin is next doubled, 
 with its wool side outward. The skins are then piled in 
 heaps of about twenty skins, and allowed to remain un- 
 disturbed from twenty-four to forty- eight hours, at the end 
 of which time the wool has become loosened, and the 
 workmen, unfolding the skins one by one, proceed to pull 
 the wool off, keeping the various qualities separate. When 
 the wool is removed, the pelts are thrown first into water, 
 and afterwards into a pit containing a weak lime liquor, 
 from which they are drawn once or twice a day, the 
 liquor being stirred or plunged each time before replacing 
 them in the pit, so as to equalise the action of the lime. 
 They are treated in this way for the first three or four 
 days, after which they are subjected to a stronger lime 
 liquor, being repeatedly drawn daily as before, and by the 
 end of from seven to ten days, according to the season, the 
 skins are ready for unhairing — that is, removing the hair 
 from the shanks and other parts left after the first opera- 
 tion. In the early part of summer, while the wool is very 
 short, the skins, after being shorn of the wool, are treated 
 somewhat differently. They are first thrown into water to 
 remove the filth, after which they are placed in lime liquor, 
 being lifted once or twice a day as before, and then sub- 
 jected to stronger lime liquors, in which they remain 
 until the wool readily yields to the touch, when it is 
 removed in the usual way. By this treatment the value 
 of the wool is impaired, but this in the case of shorn sheep 
 is of little consequence. The wool is disposed of to the 
 icoolstaplers, who cleanse and prepare it for the woollen 
 manufacturers. 
 
CHAPTER XXXIY. 
 
 PARCHMENT, VELLUM, AND SHAGREEN. 
 
 Preparation of Parchment and Vellum. — Skins for Drumheads.— Sha- 
 green. — Fish Skin, or Fish Shagreen. 
 
 Preparation of Parchment and Vellum. — The employ- 
 ment of this substance for writing purposes is of very early 
 date, and is said to have been invented by Eumenes, King 
 of Pergamos, in Asiatic Turkey, about two hundred years 
 before the birth of our Lord. In ancient times it was 
 known as pergamena, and was used, on account of its 
 durability, for writings of great importance, and as a sub- 
 stitute for the papyrus, or writing paper of the ancient 
 Egyptians. There are two principal varieties of this sub- 
 stance, which are known in commerce under the names of 
 parchment and vellum, the latter being prepared from 
 the skins of calves, kids, and still-born calves and lambs, 
 and the former from sheep and goats. In the preparation 
 of parchment and vellum, the manipulation of the skin is 
 much the same, but in the latter case somewhat greater 
 care is necessary owing to the very delicate nature of the 
 skins to be treated. 
 
 The skins are washed, limed, unhaired, and fleshed, 
 again well washed, and then stretched either on hoops or, 
 in large manufactories, upon a wooden frame called the 
 herse. This is formed of two uprights and two cross- 
 bars, well joined together by mortising, so as to form a 
 strong frame to be fixed to a wall. The four bars are 
 perforated all over with a number of holes, to receive 
 tapering boxwood pegs, in each of which is a hole, as in 
 the pegs of a violin, to receive the strings which are 
 
43? LEATHER MANUFACTURE. 
 
 employed in stretching the skin. A wooden shelf is fixed 
 above the kerse to support the tools used by the workman. 
 To stretch the skin, skewers of various sizes are used, 
 according to the size of the piece of skin to be secured. 
 Six holes are made in a straight line to receive the larger, 
 and four to admit the smaller pegs or skewers. These 
 small slits are made with a tool like a carpenter's chisel, 
 and the exact size to admit the skewer ; the string round 
 the skewer is fixed to one of the bolts of the frame, which 
 are turned round by means of a key resembling a piano- 
 forte tuning key. The skewer is threaded through the 
 skin while taut. Being thus prepared and the skin 
 well softened with water, the workman stretches it power- 
 fully hj means of the skewers ; he attaches the strings to 
 the skewers, and fixes their ends to the pegs, which he 
 then turns with the key, taking care not to allow any 
 wrinkles to be formed. It is usual to stretch the skin 
 more in its length than in its breadth. He then takes a 
 fleshing tool, which is a double-edged knife made fast in 
 a double wooden handle, in both hands, and scrapes or 
 shaves the skin from above downwards, by which he 
 removes the fleshy matters, which are afterwards collected 
 for glue-making. The herse is then turned round from 
 the wall, and the grain side of the skin is then scraped 
 With the tool in an inverted position, so as not to cut the 
 grain of the skin. 
 
 The herse is again turned, and the flesh side of the 
 skin is next dusted over with sifted chalk or slaked lime, 
 and is then rubbed over in all directions with a large 
 piece of pumice-stone, previously rubbed flat upon a sand- 
 stone ; the moisture in the skin is quickly absorbed by the 
 chalk. When sufficiently rubbed on the flesh side, the 
 skin is again turned, and the grain side rubbed in the 
 same way, but without the use of lime or chalk. The 
 above operation is generally applied only to the better 
 qualities of parchment or vellum. The skin is then allowed 
 to dry upon the frame in the shade, care being taken to 
 avoid sunshine and also frost. In very hot and dry 
 weather the skin is damped with a wet cloth, to prevent 
 
PARCHMENT, VELLUM, AND SHAGREEN. 439 
 
 it from drying too quickly ; the skewers are tightened 
 after each damping. 
 
 When quite dry, the chalk powder is removed by rub- 
 bing the skin with the wool side of a piece of lamb skin. It 
 is of great importance in pumicing not to injure the texture 
 of the skin. If the skins are greasy they must be immersed 
 in the lime-pit for a week or ten days, then stretched 
 again upon the herse, and afterwards handed to the scraper, 
 who here employs an edge tool of the same shape as the 
 fleshing knife, but larger and sharper. He mounts the 
 skin upon a frame like the herse, but extends it merely 
 with 'cords, without skewers or pegs, and supports it 
 generally upon a piece of raw calf skin strongly stretched. 
 The tail of the skin being placed towards the bottom of 
 the frame, the workman pares off with a sharp knife any 
 considerable irregularities, and then scrapes the outside 
 surface obliquely downwards with the proper tools till it 
 becomes perfectly smooth. Any remaining irregularities 
 are removed with the pumice-stone. This operation is 
 performed by laying the rough parchment upon an oblong 
 plank of wood in the form of a stool, the plank being 
 covered with a piece of soft parchment stuffed with wool, 
 forming a cushion, for the grinding operation. It is the 
 grain surface only that requires pumicing. The famous 
 Strasburg vellum is prepared with very fine pumice- 
 stones. 
 
 Skins for Drumheads.* — The skins for drumheads are 
 prepared from the skins of calves, and for kettledrums 
 from asses' skins. These are treated in the same way as 
 above. Parchment is usually coloured only green by the 
 following process : In five hundred parts of rain water 
 boil eight parts of cream of tartar and thirty parts of crys- 
 tallised verdigris ; when this solution is cold, pour into it 
 four parts of nitric acid. Moisten the parchment with a 
 brush, and then apply the above liquid evenly over the 
 surface. Lastly, the necessary lustre may be given with 
 albumen (white of eggs), or mucilage of gum arabic. ( Ure.) 
 
 * The skins for banjos and tambourines are generally prepared from the 
 skins of still-born calves. 
 
44° LEATHER MANUFACTURE. 
 
 The sieves used in powder-mills for granulating the 
 gunpowder are made from parchment prepared from hog 
 skins. English vellum is frequently made from split sheep 
 skins. 
 
 Shagreen. — This name is given to a peculiar kind of 
 parchment, and is prepared from the skins of the horse, 
 wild ass, and camel, as follows : The skin is freed from 
 its hair and cuticle by being long soaked in water, and 
 after dressing with the currier's fleshing knife is sprinkled 
 over, whilst still wet and stretched, with the seeds of a 
 species of Chenopodium, which are imbedded in it by strong 
 pressure, and in this state it is dried. The seeds are then 
 shaken off, and the surface is rubbed or shaved down nearly 
 to the bottom of the seed-pits or indentations ; it is next 
 soaked in water, by which the skin swells, and the recently 
 depressed surfaces rise into a number of minute promi- 
 nences ; it is then tawed with alum, and is lastly dyed and 
 smoothed off, or saturated with mutton tallow. Black is 
 given to the skin by means of galls and copperas, blue 
 with a solution of indigo, green with copper filings and 
 sal ammoniac, and red with cochineal and alum. Sha- 
 green was formerly extensively used for covering the 
 cases of watches, spectacles, and surgical instruments. 
 
 Fish Skin, or Pish Shagreen. — This is prepared from 
 the skins of certain species of shark, which are covered 
 with horny projections in lieu of scales. The skins are 
 stretched upon frames and dried, in which condition they 
 are sent to market. When deprived of the projecting 
 spines they are dyed and used for covering small boxes, 
 tubes of small telescopes, &c. 
 
CHAPTER XXXV. 
 GUT-DRESSWG. 
 
 Preparation of Cattle Intestines : Continental Method. — Goldbeaters' Skin. 
 — Lathe Cords. — Cords from Sheep Intestines. — Cords for Tennis Bats, 
 &c. — Whipcords. — Gut Strings for Musical Instruments. 
 
 The art of gut-dressing consists in separating the mus- 
 cular coat of the intestines of certain animals from its 
 external or peritoneal covering, and from its internal 
 lining, or mucous membrane, and is divided into two 
 distinct branches : 1, the preparation of the intestines of 
 oxen and cows to be used in the preparation of alimentary 
 substances, as sausages, polonies, &c. ; and 2, the prepara- 
 tion of the intestines of sheep for the manufacture of 
 cords or strings for musical instruments and various other 
 purposes. 
 
 Preparation of Cattle Intestines : Continental Me- 
 thod. — Dussauce describes the workshop of the gut- 
 dresser as "a room about 20 feet long, 16 feet wide, and 
 12 feet high, with four windows. Around the sides of 
 the room are ranged casks holding about sixty gallons 
 each, and in the middle of the floor are fixed wooden 
 stages for attaching hooks. A well is usually sunk in the 
 yard to receive the waste matters of the factory." 
 
 There are eleven distinct operations in gut-dressing, the 
 first of which is — 
 
 Scouring. — As the small intestines of oxen and cows are 
 received from the slaughter-house they are steeped in water 
 to moisten and smooth them, so that the knife may slide 
 easily over their surfaces. One end of the intestine is 
 now tied into a kind of knot round a hook to one of the 
 
442 LEATHER MANUFACTURE. 
 
 stakes in the centre of the room, the hook heing ahout six 
 or seven feet above the floor. The workman then grips 
 the depending portion between the forefinger and thumb 
 of his left hand, and gradually slides the hand down along 
 the whole length of the intestine, and follows its motion 
 by passing a knife, held in the right hand, over the sur- 
 face, to separate the fat as far as possible from the outer 
 coat. Another portion of gut is treated in the same way, 
 and so on until the entire caskful has been cleaned. Any 
 portions which have been accidentally cut by the slaughter- 
 man are laid aside. The fatty matter scraped from the gut 
 is well washed and melted, or rendered, as it is termed, and 
 disposed of to the soapmaker. 
 
 Turning Over. — The intestines are next washed in a 
 large cask half filled with water, and the workman next 
 proceeds to turn them inside out by introducing a thumb 
 into the interior of each, and working the gut upon it 
 with the fingers until the whole length is inverted. A 
 number of the pieces are then tied together at their ends 
 with a cord attached to the edge of the cask, and when a 
 sufficient number of inverted intestines are thus secured 
 they are ready for the next operation. 
 
 Putrid Fermentation. — The object of this process is to 
 decompose the mucous lining and other parts which have 
 to be separated from the middle coat of the intestine, and 
 if the operation is not conducted with great care the whole 
 substance of the gut will become softened and rendered 
 useless. The putrefaction is allowed to proceed for two or 
 three days in summer and from three to eight days in 
 winter, and it is known to have progressed far enough 
 when bubbles of gas are seen to arise from the surface of 
 the intestines. 
 
 Scraping. — The pieces are first untied, then soaked in a 
 tub half full of water. The workman next proceeds to 
 remove the decomposed mucous membrane (which is now 
 outward), by scraping it off with his thumb nails until it 
 is completely removed, and he facilitates the process by 
 occasionally dipping the pieces in water. 
 
 Washing. — The intestines are put into a tub nearly full 
 
GUT-DRESSING. 443 
 
 of clean water, being stirred about several times every day, 
 the water being changed two or three times a day, and 
 the operation continued until the water comes from them 
 perfectly clear and free from smell. 
 
 Inflation. — "When thoroughly cleansed by the foregoing 
 operations, one end of each piece is tightly tied by a piece 
 of string. The workman next introduces into the open 
 end a hollow cylinder of cane or reed about 5 inches long, 
 and after making this air-tight by pressing the gut tightly 
 round it, he applies his mouth to the cane tube and inflates 
 the gut by blowing into it. He then ties the end below 
 the ttfbe, and the piece is ready for drying. 
 
 Drying. — As soon as all the pieces are filled with air 
 they are conveyed to the drying place, where they are 
 laid out separately upon horizontal poles placed about 
 5 feet from the ground, and here they are left until dry. 
 When thoroughly dry they are taken down, cut across 
 with scissors as near the ligatures as possible. They are 
 next pressed and flattened with the hand to expel the 
 air. 
 
 Measuring. — The dried pieces are next sorted into dif- 
 ferent sizes, according to the purpose for which they are 
 to be used ; they are then collected into bundles, and hung 
 in a damp place previous to being submitted to the next 
 process. 
 
 Sulphuration. — When sufficiently damp, the pieces are 
 next exposed to the fumes of sulphur, in a chamber about 
 5 feet square and 6 feet high. They are first strung on 
 sticks, and if not sufficiently moist they are sprinkled over 
 with water from a brush ; they are then suspended across 
 the upper part of the chamber to the number of about 
 100 bundles. About one pound of flowers of sulphur is then 
 put into an earthen dish placed on the floor of the room, 
 and upon this red-hot cinders are laid ; the door is then 
 quickly closed, to retain the sulphur fumes within the 
 apartment, and every aperture is secured by luting or by 
 glueing pieces of paper over them. After a few hours the 
 door is opened and the fumes allowed to escape, when the 
 pieces are found to be bleached and deprived of all objec- 
 
444 LEATHER MANUFACTURE. 
 
 tionable odour. While still damp, they are twisted into 
 hanks, packed with camphor, and are then ready for 
 market. 
 
 Goldbeaters' Skin.— This is prepared from the external 
 or peritoneal coat of the caecum or blind gut of neat cattle. 
 The workman separates and turns over the part which 
 encircles the junction of the pouch with the rest of the 
 intestines, and draws it off, inverted, from the other coats 
 to the length of 25 or 30 inches. It is then soaked for a 
 short time in a weak potash liquor, and is next cleaned 
 by scraping with a knife upon a board ; it is then soaked 
 in water, and afterwards stretched upon a kind of frame 
 from 40 to 50 inches long and 11 inches wide. This frame 
 consists of two uprights held together by two cross-bars, 
 having longitudinal grooves 2| lines in width. The outer 
 surface of the membrane is placed in contact with the 
 upper part of the frame, and it is stretched in every direc- 
 tion, after which it is glued to its rim. Another mem- 
 brane is then stretched over the first, with its outer surface 
 upward, and secured by glueing round its edges. When 
 dry, the membranes are separated by passing a knife 
 along the grooves. Each strip is then glued upon a 
 similar frame, but without grooves, and is washed over 
 with a weak solution of alum, made by dissolving one 
 ounce of alum in two quarts of water. When dry, the 
 surface is wiped over with a sponge dipped in a strong 
 solution of fish-glue in white wine, flavoured with clove, 
 nutmeg, or camphor. When this is dry a coating of 
 white of eggs is applied, and after again drying each strip 
 is cut up into pieces 5 \ inches square, which are then 
 smoothed under a press and afterwards made up into 
 leaves. 
 
 Lathe Cords.* — These are prepared from the intestines 
 of horses, cleansed and prepared as before described, and 
 the pieces are cut into bands or strips of equal width in 
 the following way : A wooden ball, furnished in its lower 
 part with four equidistant cutting blades, is fixed by a 
 
 * Gutta-percha and vulcanized india-rubber have greatly superseded 
 gut cords for lathes. 
 
GUT-DRESSING. 445 
 
 wooden upright to a bench. The end of an intestine is 
 then drawn over this ball, and as the gut is pulled down- 
 ward it becomes divided into four equal strips. From four 
 to eight of these strips, according to the thickness of cord 
 required, are tied with a peculiar knot to one end of a 
 stout piece of cord ; the end is passed round a peg inserted 
 into a hole in a solid post, to the side of which a number 
 of pegs are attached. About ten yards from this post is 
 another post, also provided with pegs ; over one of these 
 latter the middle strip of the cluster is bound, the other 
 end being brought back and attached to the first peg by 
 anoth'er knotted cord. The tied ends of the strips are then 
 attached to the wheel by a hook connected with a whirl, 
 which is made to revolve until the strips are sufficiently 
 twisted. The twisted end is then kept stretched by attach- 
 ing it to the peg, and any projecting filaments are cut off. 
 After stretching some time, the cords are twisted again, 
 and the third and fourth time this is done by hand, being 
 rubbed with and drawn through a bunch of moistened 
 horsehair each time after twisting, and again stretched 
 out between the two posts. If the cord is not smooth and 
 even when the twisting is completed, it is rubbed with a 
 piece of dog skin. The cord is then dried, but some manu- 
 facturers expose it to the fumes of sulphur. The ends are 
 now cut off and the cord is rolled into a coil. 
 
 Cords from Sheep Intestines.* — It is important that 
 the intestines should be fresh — that is, free from decom- 
 position. They are first cleansed from fcecal matter and 
 washed ; they are then taken to the workshop, where they 
 are soaked in a tub of water and deprived of adhering fat. 
 The smaller ends are then tied together and laid on the 
 edge of the tub, while the remainder are allowed to steep 
 in the water for several days, the water being frequently 
 changed. The peritoneal and mucous coats are then re- 
 moved by placing the intestines on a bench, which slopes 
 towards the rim of the tub, and the surface is scraped with 
 the back of a knife-blade to separate the membranes to 
 the width of about half the circumference. This is done 
 * Erroneously called catgut. 
 
446 LEATHER MANUFACTURE. 
 
 by pulling it off in pieces from the smaller end of the 
 intestine towards the larger end. The gat is next soaked 
 in water for twenty-four hours, and afterwards scraped 
 clean upon the bench with the rounded back of a knife. 
 About 8 feet of the larger ends are now cut off for use by 
 the sausage-makers ; the remainder are cut into lengths 
 and stratified with salt, which is termed curing. After 
 remaining in the salt for some days they are soaked in 
 water for a night, and next day they are immersed in a 
 ley composed of pearlash 8 oz. dissolved in water 4 gal- 
 lons. The ley is poured over the intestines, and every 
 two or three hours the liquor is poured off and the intes- 
 tines are examined to ascertain if they have been suffi- 
 ciently acted upon by the alkali. They are next drawn 
 several times through a brass thimble open at both ends, 
 and then sorted, according to their sizes, for the different 
 purposes to which they are to be applied. 
 
 Cords for Tennis Bats, &c. — These are generally made 
 from intestines of inferior quality, or such as have been 
 stained by incipient putrefaction. The pieces while still 
 moist are sewn together with strips of the outer mem- 
 brane, or filandre, each junction being cut obliquely, so as 
 to make it level and strong. Three or four of these intes- 
 tines are thus attached by strings to the whirl, and are 
 twisted as usual, after which the cord is smoothed and 
 deprived of moisture by the workman's hand ; it is then 
 stretched for a time, when it is again twisted and rubbed 
 with the bunch of horsehair. The inferior kinds of cords 
 are prepared by twisting one gut along with two or three 
 lengths of the outer membrane. 
 
 Whipcords. — These are made from intestines of good 
 quality, prepared as before, each end being twisted sepa- 
 rately, since these cords are seldom made from two intes- 
 tines sewn together. The cord is " sulphured" once or 
 twice, and is then smoothed and dried, after which it is 
 coiled in certain lengths for sale. 
 
 Gut Strings for Musical Instruments. — Of all the 
 purposes to which the intestines of animals are applied, 
 none is so important as their conversion into what is 
 
GUT-DRESSING. 447 
 
 commonly called catgut, for the strings or cords of 
 " stringed. " instruments, including the whole violin 
 family and the harp. From the earliest period Italy has 
 been most famed for the production of violin strings of 
 the finest quality, a reputation which she has main- 
 tained to the present day; and though a vast number 
 of these strings are made both in England and various 
 parts of the Continent, the " Roman strings," as they are 
 called, are justly held in the highest estimation. It is a 
 well-known fact that the membranes of lean animals are 
 much tougher than those of animals in a higher condi- 
 tion, and it is to this fact that the superior quality of the 
 strings made in Naples is due, since the sheep from which 
 the raw material is obtained are exceedingly small and 
 also lean. The strings made from the intestines of the 
 fat sheep of the London market are well known to be 
 greatly inferior in toughness and durability to those of 
 Neapolitan make ; and from the frequency with which the 
 former break when being tuned up to concert pitch, they 
 often cause much disappointment, irritation, and incon- 
 venience to musicians. 
 
 Treatment of the Intestines. — The intestines being 
 cleansed as before, are steeped in the potash leys (clarified 
 with a little alum), progressively stronger each day, for 
 four or five days, until they are sufficiently swollen and 
 bleached. They are then passed through the thimble, and 
 again cleansed in the ley, after which they are washed, 
 twisted, and sulphured for two hours, which operation is 
 sometimes repeated several times. They are next polished 
 with horse-hair cords and dried. The strings are known 
 to be sufficiently dried when one of the strands, upon being 
 removed from its peg, shows no disposition to curl, but 
 remains perfectly straight in the position in which it is 
 held. When the strings have reached this point they 
 are rubbed over with olive oil, cut at the ends, and 
 coiled up. 
 
 The violin fourth strings, which are covered with plated 
 copper wire, are neither sulphured nor oiled. The string 
 to be wire-covered is cut off to the length of 1\ yard ; one 
 
448 LEATHER MANUFACTURE. 
 
 of its ends is attached to the hook of the wheel and the 
 other to the ring of a whirl, which keeps the string 
 stretched by means of a weight at the end of a cord 
 fastened to it, and passing oyer a pulley. The wire is 
 then fastened around the string close to the whirl, and as 
 the wheel is made to revolve the string and the whirl 
 turn with it. The workman supports the string with his 
 left hand, and the wire passing through his right hand 
 is made to revolve around it in close spiral turns until it 
 is entirely and equally covered (Dussauce). The utmost 
 skill and dexterity on the part of the workman are 
 required for the manufacture of violin and harp strings, 
 which he can only acquire by extensive experience and 
 care. 
 
CHAPTEE XXXVI. 
 GLUE-BOILING. 
 
 Treatment of Glue-piecos, &c. — French Glue. — Parchment Glue. — 
 ^ Size. — Glue AVaste. 
 
 Treatment of Glue-pieces, &c. — The glue -pieces and 
 other animal matters used in the manufacture of glue are 
 put into a large tank containing milk of lime, in which 
 they remain for about two weeks, the lime being renewed 
 several times. They are then taken out, with the lime which 
 adheres to them, and spread out in a layer two or three 
 inches thick upon a sloping pavement to drain and dry, 
 being turned over by means of prongs several times a day. 
 The action of the lime destroys all the tissues, blood, &c, 
 rendering them soluble, by which they become separated 
 from the glutinous matter, which is thereby put into a 
 condition to dissolve more freely in hot water. By ex- 
 posing the lime to the action of the air, it loses its caus- 
 ticity by attracting carbonic acid, and is thus prevented 
 from acting injuriously upon the glue when the mate- 
 rials are boiled. The glutinous matters are next put into 
 baskets and washed in a stream of water, after which 
 they are placed, while still wet, in a flat-bottomed copper 
 boiler, furnished with a perforated false bottom to pro- 
 tect the animal matter from being burnt by the heat of 
 the fire. 
 
 -■First Boiling. — The copper is filled about two-thirds 
 with soft water, when the washed material is introduced and 
 piled up above the flange of the boiler ; the fire is then 
 kindled, and as the heat increases the material sinks into 
 the liquid, and after a few hours becomes completely 
 immersed in the liquid. During this time the contents 
 
 2G 
 
45° LEATHER MANUFACTURE. 
 
 of the boiler are frequently stirred, and the whole boiled 
 gently. 
 
 Dratoing off the Liquor. — The liquid is drawn off by a 
 tap connected to the bottom of the boiler, and beneath its 
 false bottom, and the first, second, and third liquors, re- 
 presenting different qualities, are reserved for glues of 
 proportionate value, the product gradually decreasing in 
 value as the boiling progresses. It has been proved that 
 gelatine undergoes various changes of condition after it 
 is dissolved by continued boiling-, and it should therefore 
 be drawn off whenever it is sufficiently strong to form a 
 clear gelatinous mass on cooling, and which will cut into 
 tolerably firm slices with a thin wire. This is readily 
 ascertained by putting a little of the liquor in a small 
 vessel and exposing it in the air to cool, when in the 
 course of a few minutes it should gelatinise ; if such is 
 not the case, the boiling must be continued for a longei 
 period. As soon as the proper condition of the liquor is 
 reached the fire is checked, and the contents of the boiler 
 allowed to settle for about fifteen minutes. The tap or 
 stopcock is then turned a little and all the liquor allowed 
 to flow into the settling copper, situated below the first, 
 and which is immersed in a hot-water bath to keep the 
 fluid hot. 
 
 Gelatinising. — After three or four hours the clear liquor 
 is run off into a series of square wooden boxes slightly 
 narrower at the bottom than at the top. The bottoms of 
 these boxes are cross-grooved to regulate the size of the 
 squares of glue. These boxes are placed very level on 
 the stone floor of the apartment, which must be rendered 
 very clean, so that in the case of leakage the glue may be 
 recovered. The liquid glue is poured into the boxes 
 through a funnel, provided with a filter-cloth, until it 
 reaches the upper rim of each box. The apartment re- 
 quires to be very dry and cool to aid the solidification of 
 the glue. 
 
 Cutting. — If the boxes have been filled overnight, the 
 glue will generally be sufficiently firm to cut on the 
 following morning. The boxes are then removed to a 
 
GLUE-BOILING. 451 
 
 well- ventilated upper loft, in which the air is admitted 
 from all points ; they are then carefully turned upside 
 down upon a table, previously moistened to prevent the 
 glue from sticking to it. The glue is then loosened from 
 the sides of the boxes by passing a moist long-bladed 
 knife round the inner sides. The block of glue is first cut 
 into slices horizontally by means of a thin brass wire 
 stretched in a frame like that of a frame-saw, and the 
 cuts are guided by rulers placed at proper distances to 
 suit the required thickness of the glue cakes. The 
 square cakes are formed by cutting with a moist knife 
 through the lines formed by the grooves in the bottom of 
 the box. 
 
 Drying. — The gelatinous squares are next lifted very 
 carefully and laid upon nets stretched upon wooden 
 frames ; as each frame is filled another is placed above it, 
 to be filled in its turn, and so on. The frames are set 
 over each other, with a space of about three inches be- 
 tween, and upon small wooden pegs fitting into holes in 
 uprights fixed round the room, so that the air may have 
 free access on every side. The frames, supported by 
 the wooden pegs, slide to and fro like a drawer, which 
 enables the workmen to shift them from time to time, 
 to turn the cakes over, which is done two or three times 
 each day. 
 
 There is no detail in the manufacture of glue which is 
 so uncertain as that of drying the jellified material, espe- 
 cially in the earlier stages ; if the temperature of the 
 atmosphere should rise above a certain degree, the gelatine 
 may run, and trickle through the netting upon the cakes 
 beneath, or may become just sufficiently soft to firmly 
 attach itself, when drying, to the netting, rendering it 
 necessary to plunge the net into boiling water to discon- 
 nect the cakes ; and even if these untoward difficulties do 
 not arise, the augmented temperature will render the cakes 
 so soft as to put them out of proper shape. Again, if the 
 gelatine become frozen, the cakes are liable to crack, and 
 thus necessitate remelting. In damp and foggy weather 
 the glue is liable to become mouldy on the surface, while 
 
452 LEATHER MANUFACTURE. 
 
 if the air be too dry and hot, it is likely to dry too rapidly, 
 causing it to crack in numerous places. The only remedy 
 for the above evils is to keep the flaps of the drying-room 
 windows closed as occasion may require, and if possible to 
 conduct the operation in the spring or autumn. When 
 the cakes have been dried upon the nets they may still 
 retain a certain amount of elasticity, which would render 
 them unsaleable ; when such is the case they require to be 
 dried in a stove by moderate heat. 
 
 Glossing. — In order to give the cakes the bright glossy 
 surface which is characteristic of this article, the dried 
 cakes are dipped one by one into hot water for an instant, 
 and they are then brushed over with a brush, also dipped 
 into hot water. The cakes are then spread upon a hurdle, 
 and are afterwards placed in the stove-room if the weather 
 be damp, until the surfaces are perfectly dry, when they 
 are ready for packing into casks for sale. 
 
 Second Boiling. — After the lirst liquor has been removed 
 as before described, fresh water is put into the copper, 
 and the boiling continued until the mass has a gelatinous 
 appearance, when the liquor is drawn off by the stopcock 
 as before, and is then submitted to the same operations as 
 the first liquor. 
 
 Third Boiling. — The remaining grounds are next treated 
 with a fresh supply of water, or weak liquors containing 
 some gelatine. The bottoms, or grounds, are afterwards 
 taken out of the boiler and placed in bags, which are 
 submitted to pressure to extract as much of the liquor as 
 possible. 
 
 The above three boilings yield three different qualities 
 of glue. The lirst is pale coloured, and is the most suit- 
 able for uniting all kinds of woodwork. The second and 
 third qualities are often preferred, however, by workmen 
 who innocently believe that a dark-coloured glue has the 
 strongest adhesive power. 
 
 French Glue. — This is made from the gelatine of bones. 
 The bones are first treated with hydrochloric acid, which 
 dissolves the phosphate of lime, leaving the gelatinous 
 substance of the bones in a soft and soluble condition, 
 
GL UE-BOILING. 45 3 
 
 which is afterwards dissolved and converted into glue. 
 The product is, however, of very poor quality, and is 
 soluble in cold water — a proof of its inferiority. Good 
 glue does not dissolve in cold water, but is merely soft- 
 ened by it. 
 
 Parchment Glue is prepared from the shreds or shavings 
 of parchment, vellum, white leather, &c, by boiling in 
 water; it is nearly colourless, and without odour. 
 
 Glue of inferior quality may also be prepared from the 
 tendons and other offals of the slaughter-house, but the 
 refuse of the tanneries, such as the ears of oxen, calves, 
 sheep^ &c, form a better glue stock, while the parings of 
 ox and cow hides are the best of all materials for glue- 
 making. 
 
 Size. — Ordinary size, such as is used in plastering and 
 other coarse work, is prepared from the same materials 
 as common glue, but the liquid is not evaporated to so 
 great an extent as is requisite for the latter substance ; 
 being always kept in a soft condition so as to be readily 
 soluble in water, the gelatine solution is made of such a 
 strength that, when cold, it will set into a firm jelly, or, as 
 it is called, size. Other varieties, of a superior quality, 
 are, however, prepared for manufacturing gelatine, for 
 thickening soups, and other domestic purposes, from se- 
 lected materials, such as calves' pates, &c. In preparing 
 this quality of size greater care is taken to remove the 
 lime than is necessary in ordinary glue-making, and to 
 accomplish this the pieces, after liming, are treated in a 
 very dilute solution of hydrochloric acid. The boiling is 
 usually effected by means of steam-heat, and the liquid, 
 when in the proper condition, is either run out into small 
 casks for sale, or into large vats, and when cold is broken 
 up and packed in casks. For making the finest qualities 
 of size, for use as an article of diet, steam jacket-pans are 
 employed in boiling the materials. The size used by 
 paper-makers is of the best quality manufactured by 
 ordinary glue makers. 
 
 Glue Waste. — The refuse left after the final boiling is 
 thrown aside for manure. Since it rapidly decomposes, 
 
454 LEATHER MANUFACTURE. 
 
 however, it soon becomes offensive, rendering its removal 
 exceedingly unpleasant after about twenty-four hours. 
 MM. Leblanc, of Lyons, have discovered in this refuse 
 matter a considerable quantity of a fatty substance, which 
 can be used in the manufacture of soap as well as for 
 lubricating purposes. It can be extracted by means 
 of bisulphide of carbon, petroleum, benzol, &c, but sul- 
 phuric acid is recommended as being cheaper and safer 
 in use. A vessel capable of holding from 50 to 100 
 gallons, heated by steam or otherwise, may be used for 
 the purpose. 
 
 For 220 lbs. of refuse, 11 gallons of water are taken and 
 acidified with sulphuric acid, till it stands at about 6° to 
 8° Baume. The whole is then boiled, and after a suitable 
 mixing has been effected, sulphuric acid of 48° Baume is 
 poured in by degrees, until a complete saturation has 
 taken place, or until the fatty substance has been sepa- 
 rated. The quantity of the 48° acid varies according to 
 the greater or lesser proportion of gelatine in the waste. 
 It averages about 10 per cent. This operation lasts about 
 two or three hours. 
 
 The mass is then placed in cloths, each holding about 
 35 to 45 lbs., and these are placed under a hydraulic press 
 with a division between each cloth. The fluid obtained is 
 directed into receptacles, and the fatty substance on the 
 top is removed. The pressed cakes remaining are very 
 rich in nitrogenous substances, which are as effective for 
 manuring purposes as the refuse in its original form. The 
 cakes are dried, and can then be stored until required for 
 use. 
 
CHAPTER XXXVII. 
 
 UTILISATION OF TANNERS' WASTE 
 
 Spent Jan.— Guest and Court's Process. — Hide and Skin Cuttings. — 
 Hair Waste. — Lime "Waste. — Glucose in Leather. 
 
 Spent Tan. — When we reflect upon the vast quantity of 
 tan refuse that is annually produced in the United King- 
 dom we cannot be surprised that many efforts should be 
 made — even by persons outside the trade — to turn this 
 waste material to practical account. It had long been the 
 practice at some tanneries to employ it when dried, or 
 partially dried in the air, as fuel ; again, a considerable 
 quantity has been, and is now, used as manure. In 1852 
 Mr. J. B. Hoyt, of New Jersey, conceived the idea of burn- 
 ing wet spent tan in a detached brick furnace, and 
 succeeded in obtaining sufficient heating power to drive 
 his machinery by its agency, and practically adopted this 
 method of utilising the waste tan from that time. The 
 great success of his system created quite a revolution in 
 the American tanneries, and its adoption became general. 
 Ill this country Messrs. Huxham and Browns have con- 
 structed a tan-burning boiler, which, we believe, has 
 proved very efficient. 
 
 Another and still more important use for spent tan — 
 should any of the patented processes prove successful — is 
 in the conversion of the fibrous waste into pulp for paper- 
 making. This would doubtless be the most profitable 
 purpose to which the material could be applied if an 
 effectual and economical method of pulping and bleaching 
 could be introduced. In 1881 Messrs. Guest and Court 
 obtained a patent for converting waste tan into pulp for 
 
456 LEATHER MANUFACTURE. 
 
 paper making, the abridged process of which is given 
 below. 
 
 Guest and Court's Process. — The spent tan is put into 
 a hopper, from which it gradually passes between, and is 
 crushed by, two or more revolving rollers, the object of 
 which is to open the fibres and break up the knots of the 
 waste material. The inventors prefer to feed the rollers 
 with the spent tan in a semi-dry state. The fibres being 
 thus separated to some extent, the mass is introduced in 
 convenient quantities into a rotary boiler or agitator 
 containing a solution of caustic soda in the proportion of 
 one-twentieth part to the water used. The boiler is then 
 closed, steam admitted, and the whole agitated by means 
 of arms or cutters in the interior, and the separating or 
 opening (disintegrating) process maintained. The mass 
 may be washed in the boiler or in a separate vessel. 
 When it is desired to bleach the mass, it is subjected to 
 the action of bleaching materials. In the event of any 
 such process becoming really practicable, it would then be 
 worth while to keep spent bark separate from valonia, &c. 
 
 Hide and Skin Cuttings. — These are commonly called 
 " glue pieces," and are disposed of to the glue manufac- 
 turers, but their value depends greatly upon the care 
 taken to preserve them from decomposition. This is more 
 especially important when they are to be used for making 
 size for paper-making, since the least smell or "taint" 
 would be noticeable in the paper, and greatly reduce its 
 value. It is also very important that the fine glues used 
 in bookbinding should be free from objectionable smell ; 
 therefore it will be well understood that the value of the 
 glue pieces will depend upon their not having undergone 
 decomposition while in the possession of the tanner. 
 When it is borne in mind that glue pieces which have 
 become tainted can only be employed for making what is 
 known as carpenters' glue, their preservation from decom- 
 position should be a matter of great consideration in order 
 to maintain their proper value. 
 
 Respecting the preservation of glue pieces, Jackson 
 Schultz makes the following observations : " Whether 
 
UTILISATION OF TANNERS' WASTE. 457 
 
 from green or dry stock, the trimmings should be thrown 
 into weak lime as soon as they leave the beam, and should 
 be retained in this lime until the hair will almost drop 
 off; when in this condition they should be thrown into a 
 revolving wheel (tumbler), or may be put into the hide 
 mill, and worked until all the hair has been separated 
 from the pieces. If a bountiful supply of water has been 
 allowed to run on while the wheel or mill was in operation 
 all the hair will have worked off and separated from the 
 pieces, which will then have parted with so much of their 
 lime as to make them, when dry, flinty and hard; to 
 avoid- this they should be thrown back into the lime for a 
 few days, and again ' raised.' Before they are taken out 
 to dry they should be thoroughly washed. The drying 
 should be in the open air, and if on a flat board surface 
 the pieces should be frequently turned. Care should be 
 taken to wash off all the loose lime, so that the pieces 
 may present an attractive uniform white and clean sur- 
 face. When they are fully dried, they should be pressed 
 into uniform bales [cakes]. Under no circumstances 
 should any tainted or damaged piece be allowed to go into 
 the bale. Paper-makers will use such hide offal for 
 sizing, and pay three or four cents per pound more for it 
 than glue-makers can afford to pay. Calf skin shanks 
 and pates are worth more for this purpose than hide 
 cuttings, and should always be kept separate." 
 
 The above observations of a thoroughly practical and 
 successful tanner should command attention, and which 
 they will doubtless receive, from those who are desirous 
 of deriving the full advantage from such valuable offal as 
 the trimmings of hides and skins. The cuttings from 
 neat cattle are more valuable than those of the sheep, 
 while those from goats are of less value than the latter. 
 
 Hair Waste. — Formerly cattle hair was only used by 
 plasterers to promote the binding properties of mortar, 
 but of late years this material — especially calves' hair — 
 has been employed in the manufacture of cloth, carpets, 
 and felting. It is of importance, therefore, that this waste 
 product should be preserved and rendered saleable by 
 
4SS LEATHER MANUFACTURE. 
 
 being well cleaned and washed. For this purpose hair 
 washing machines have been introduced. 
 
 Lime Waste. — If we bear in mind the very small 
 amount of lime which water is capable of dissolving, 
 namely, only 88 - 48 grains per gallon at the temperature 
 of 60° Fahr., the common practice of putting the cleansed 
 skins or hides into what is termed " weak lime," or " old 
 lime " — that is to say, lime that has been used over and 
 over again — would appear to be open to objection. When 
 these old liquors contain little or no caustic lime in solution, 
 and chiefly carbonate of lime as the residuum, it is ques- 
 tionable whether the cost of labour in handling and loss of 
 time involved in what may be an inert process, would not 
 be better applied to treating the skins in really active 
 (that is, fresh) liquors. The cost of lime is but small, and 
 the amount actually exhausted in the process of depilation 
 cannot be much. We venture to suggest, therefore, that 
 economy would be found, not in trying to get a little more 
 out of weak liquors, but in discarding them altogether so 
 soon as they give evidence of inaction. Again, the prac- 
 tice of using large proportions of lime in charging a pit 
 would seem to be objectionable, and for this reason : when 
 the lime has fre.ely acted upon the fatty matters of, say, 
 100 hides, the liquor becomes a solution of lime-soap, and 
 it is doubtful whether in this condition it is capable of 
 holding much, if any, free lime in solution. If this be so, 
 the liquor would become inoperative as a depilatory, no 
 matter how much lime might remain at the bottom of the 
 pit. Schultz urges that no undissolved lime should enter 
 the pit ; and although we cannot go quite so far as that 
 gentleman, we do think that a much smaller proportion of 
 lime than is usually adopted would answer every purpose, 
 and would be far less wasteful. Our reason for differing 
 from the great American authority is, that we believe the 
 undissolved lime — which becomes diffused through the 
 liquor by the operation of 'plunging each time the skins are 
 returned to the pits — has a direct and powerful action 
 upon the animal tissues, the epidermis and subcutaneous 
 areolar tissue, independent of the dissolved lime, which, aa 
 
UTILISATION OF TANNERS' WASTE. 459 
 
 we have shown (p. 117), only amounts to 11*6 grains in each 
 pint of the liquor at ordinary temperatures. When the 
 liquors are highly " soapy/' if we may use the term, the 
 action of the lime would be retarded. 
 
 The lime waste of the tanneries is disposed of as manure, 
 but the waste liquors are not so easily got rid of, since if 
 they are suffered to run into rivers these streams would 
 soon become uninhabitable to the finny tribe. A small 
 quantity of sulphuric acid, added to the exhausted lime 
 liquors, would liberate the fatty acids of the lime-soap, and 
 these could be collected as a scum from the surface. If 
 this were done exactly to the point of saturation (that is 
 to say, without excess of acid), the waste liquor would be 
 rendered innocuous, and its entrance into rivers would be 
 at all events comparatively harmless. If a small portion 
 of lime happened to be present in the waste liquor, this 
 would be thrown down as an insoluble sulphate of lime. 
 
 Glucose in Leather. — It has been stated that the 
 falsification of the weight of leather, by adding glucose, 
 or grape sugar, is carried on somewhat extensively, 
 and the shoe trades are seeking protection from this 
 system of fraud. The presence of glucose in leather may 
 be ascertained in the following way : Steep a piece of 
 the suspected leather in a little water for twenty-four 
 hours, when the glucose will become dissolved, forming a 
 thickish syrupy liquid. Or, if two pieces of the leather 
 be moistened and then placed together and left for a time, 
 they will be found to adhere firmly, which in the case of 
 pure leather would not occur. It is stated that samples of 
 sole leather have been found to contain from 30 to 40 per 
 cent, of glucose, but this seems incredible. It is a 
 peculiarity of leather treated with grape sugar that after 
 being wetted it is difficult to dry. 
 
460 
 
 LEATHER MANUFACTURE. 
 
 French Metrical or Decimal Measures of Length. 
 
 Names. 
 
 Eq. in Metres. 
 
 Equivalents in 
 
 English Inches at 
 32° Fabr. 
 
 English Long Measure at 
 W Fahr. 
 
 Millimetre . . 
 Centimetre . . 
 Decimetre .... 
 
 Metre 
 
 Decametre . . 
 Hectometre . . 
 Kilometre .... 
 Myriametre . . 
 
 •001 
 •01 
 
 •1 
 1- 
 
 ro- 
 
 100- 
 
 1000- 
 10000- 
 
 •03937 
 
 •39371 
 
 3-93708 
 
 39-37079 
 
 393-70790 
 
 3937-07900 
 
 39370-79000 
 
 39370790000 
 
 4j h .3 "« "S 
 
 1 3-37 
 10 2 9-7 
 109 1 1-078 
 4 213 1 10-3 
 6 1 156 9-17 
 
 *** The standard unit of the above table is the metre, which has been 
 determined to be 39-37079 inches at 32" Fahr. (Capt. Kater) ; the Eng- 
 lish foot is taken at 62° Fahr. The true length of the metre, reduced to 
 the latter temperature, is 39-370091 English inches, a number which 
 varies from that in the table only at the fourth decimal figure. It will be 
 perceived that the principle of nomenclature adopted in applying the 
 names, was to prefix the Greek numerals to the decimal multiples, and the 
 Latin numerals to the decimal subdivisions. 
 
 French Metrical or Decimal Measures of Volume. 
 
 Names. 
 
 Eq. in Litres. 
 
 Eq. in English 
 Cubic Inches. 
 
 Equivalents in English 
 Measures. 
 
 
 
 
 73 
 
 
 
 
 
 O 
 
 P4 & 
 
 Millilitre 
 
 ■001 
 
 •0610 
 
 
 16-9 
 
 Centilitre .... 
 
 ■01 
 
 •6103 
 
 
 2 49- 
 
 Decilitre 
 
 •1 
 
 6-1028 
 
 
 3 4 10-36 
 
 Litre 
 
 1- 
 
 61-028 
 
 
 1 15 1 43-69 
 
 Decalitre 
 
 10- 
 
 610-28 
 
 2 
 
 1 12 1 16-9 
 
 Hectolitre .... 
 
 100- 
 
 6102-8 
 
 22 
 
 1 4 49- 
 
 Kilolitre 
 
 1000- 
 
 61028- 
 
 220 
 
 16 6 40- 
 
 Myrialitre . . 
 
 10000- 
 
 610280- 
 
 2201 
 
 (=275| bushels). 
 
 *** The standard unit in the above table is the litre, or the cube of the 
 one-tenth of a metre. The French centiare contains 1 square metre ; the 
 are, 100 ditto; the hectare, 10,000 ditto. The old Paris pint is equal to 
 1-678 English imperial pint. 
 
 ttt The capacity of solids and aeriform fluids is taken in cubic inches 
 or feet, in England.^ In France, the stere, or metre cube, equal to 35-31658 
 English cubic feet, is the standard unit. 
 
WEIGHTS AND MEASURES. 461 
 
 Weights and Measures of the Metrical System. 
 From the British Pharmacopoeia. 
 
 Weights. 
 
 1 Milligramme z=z the thousandth part of one gramme, or 0*001 gramme 
 
 1 Centigramme = the hundredth ,, ,, ,, 0-01 
 
 1 Decigramme = the tenth „ ,, ,, 0"1 
 
 1 Gramme ■= weight of a cuhic centimetre of wafer at 4° C. 1*0 
 
 1 Decagramme — ten grammes ..... 10*0 
 
 1 Hectogramme r= one hundred grammes . . . 100 
 
 1 Kilogramme = one thousand grammes . . . 1000-0 (1 kilo.) 
 
 Measures op Capacity. 
 
 1 Millilitre = 1 cubic centimetre, or the measure of 1 gramme of water. 
 
 1 Centilitre = 10 „ ,, ,, 10 „ „ 
 
 1 Decilitre =100 „ „ „ 100 „ 
 
 1 Litre = 1000 „ „ „ 1000 (1 kilo.) 
 
 Measures of Length. 
 
 1 Millimetie = the thousandth part of one metre, or 0-001 metre. 
 1 Centimetre = the hundiedth „ „ 0-01 „ 
 
 1 Decimetre = the tenth ,, „ 1 „ 
 
 1 Metre = the ten-millionth part of a quarter of the meridian of 
 the earth. 
 
INDEX. 
 
 A BIES CANADENSIS, 85 
 -£*■ Abusive treatment of raw hides, 
 
 53 
 Acacia, 83 
 
 arabica, 84 
 
 catechu, 84 
 
 dealbata, 8G 
 
 decurrens, 85 
 
 horrid a, 84 
 
 melanoxylon, 84 
 
 mollissima, 84, 85 
 
 nilotica, 85 
 
 pyeantha, 83 
 Acetate of iron, 281 
 
 of lime, 308 
 Acetic acid, 17, 301 
 
 fermentation, 142 
 Acid, acetic, 17, 301 
 
 carbolic, 66 
 
 catechuic, 75 
 
 catechu-tannic, 14 
 
 chromic, 262, 324 
 
 ellagic, 62, 413 
 
 gallic, 14, 57 
 
 properties of, 58, 60 
 
 gallo-tannic, 43 
 
 hydrochloric, 45, 95, 325 
 chromic, 349 
 
 krameric, 80 
 
 malic, 65 
 
 m eta-gal lie, 60 
 
 nitric, 55 
 
 oxalic, 47, 301 
 
 phosphoric, 301 
 
 pyrogallic, 14, 50, 61 
 
 pyroligneous, 65 
 
 quercitannic, 101 
 
 stearic, 312 
 
 sulphuric, 45, 95, 174 
 bate, 141 
 
 tannic, 11, 50, 301 
 
 Badviland Lienders' process 
 for preparing, 47 
 
 Acid, tannic, Berzelius' process, 44 
 Bouillon -Legrange's pro- 
 cess, 45 
 Coez's process, 47 
 Deyeux's process, 46 
 Dize's process, 45 
 Kohlrausch's process, 48 
 Merat-Guillot's process, 45 
 Pelouze's process, 43 
 Proust's process, 46 
 Schering's process, 46 
 Serturner's process, 46 
 properties of, 49 
 pure, 51 
 reactions of, 52 
 tartaric, 65, 301 
 
 Acids, depilation by, 129 
 iron blueing, 14 
 greening, 14 
 
 Acroclin, 365 
 
 Action of tannic acid on gelatine, 13 
 
 Adurla, 84 
 
 African gallnut, 87 
 
 Air-heated tumblers, 378 
 
 Albumen, 27 
 
 Alcamo sumach, 78 
 
 Alchemilla vulgaris, 49 
 
 Alcoholic extract of logwood, 304 
 
 Alder, 84 ; bark, 54, 87 
 
 Aldrich's tanning process, 171 
 
 Aleppo nutgalls, 53 
 pine, 84 
 
 Algarobiall, 84 
 
 Alkali, caustic, 53 
 
 Alkaline sores, 133 
 
 Alligator skins, 42, 432 
 
 copying by electrotype, 432 
 
 Almardelboom, 84 
 
 Almond oil, 311 
 
 sweet, 311 
 
 Alnus glutinosa, 84 
 
 Alum, 218 
 
 and salt, treatment with, 308 
 
EREATA IN INDEX. 
 
 Page 462, column 1, line 2, for ' hides ' read ' hide.' 
 „ 462, „ 1, „ 3, far < 53 ' read « 35.' 
 ,, 463, ,, 1, ,, 24,/or' Analysation of catechu ' read' Analysis 
 
 of catechu.' 
 ,, 463, ,, 1, After I. 24, insert 'Analysis of tannins, 91.' 
 
 ,, 464, ,, 1, ,, 52, for ' vegetable ' read ' enamel.' 
 ,, 464, ,, 1, ,,56, for ' setting for ' read ' setting in.' 
 „ 464, „ 2, „ 14, delete ' Blunt tools, 140.' 
 ,, 465, >> 1) >> 23, for ' fawing ' read ' tawing.' 
 „ 465, ., 1, „ 25, for ' for, 348,' read ' for chrome, 348.' 
 ,, 465, ,, 1, ,, 48, for ' analysation ' read ' analysis.' 
 „ 465, ,, 2, „ 19, after ' 91 ' insert ' 104.' 
 ,, 466, ,, 1, ,, 29, for ' analine ' read ' aniline.' 
 „ 468, „ 1, „ 2, for ' 337, 345, 346, 354' read ' 304, 337, 345, 
 
 346, 354.' 
 „ 468, „ 1, After 1. 46, insert 'I.A.Ij.T.G. method, 104.' 
 
 ,, 468, ,, 2, ,, 21, for ' fellmongering, 434 ' read ' fellmonger- 
 
 ing, 287, 434.' 
 ,, 468, ,, 2, ,, 24, for ' ascetic ' read ' acetic' 
 ,, 469, ,, 2, ,, 35, for 'one- and two-bath methods' read 'one- 
 bath method.' 
 ,, 470, „ 2, „ 26, for 'stocking, 400,' read 'stocking, 111,400.' 
 ,, 471, ,, 1, „ 11, for ' Illustration of the skin, 86,' read 
 
 ' Illustration of the skin, 26.' 
 ,, 472, ,, 2, „ 25, for ' shamoy, 39,' read ' chamois, 39, 357.' 
 ,, 472, ,, 2, ,, 46, for ' power ' read ' process.' 
 „ 474, „ 1, After I. 26, insert ' I.A.L.T.C. method of 
 
 estimating tannin, 104.' 
 ,, 480, „ 2, ,, 20, for 'Striker ,Priestman's, 407,' read 'Striker, 
 
 Priestman's, 165, 407.' 
 „ 481, „ 2, After I. 33, insert ' I.A.L.T.C. method of 
 
 estimating, 104.' 
 ,, 484, ,, 1, ,, 8, for ' graining in after, 382,' read ' graining 
 
 after, 382.' 
 
 Watt's 'Leather Manufacture.' 
 
INDEX. 
 
 46; 
 
 Alum dressing, 307, 314, 317 
 Alumina,, 47 
 
 chromate of, 175 
 
 sulphate of, 170 
 Aluming, 308, 319 
 Aluminium chromate, 2G3 
 Amber varnish, 298 
 Amboyna kino, 75 
 American bleaching processes, 270 
 
 method of drying the tanned 
 butts, 156 
 
 pearlash, 176 
 
 pendulum roller, 167 
 
 perseverance and ingenuity, 323 
 
 rocker handler, 154, 242 
 
 tanning, 228 
 
 tra^de in leather, 372 
 
 turret drier, 159 
 
 union splitting machine, 322 
 Ammonia, 119 
 
 carbonate of, 45, 141 
 Ammoniacal salts, 255 
 Ammonium, chromate of, 263 
 Analysation of catechu, 75 
 Anatto, 382 
 
 Aniline colours, dyeing with, 300, 
 337, 345, 346, 354 
 dyeing with pure, 304 
 in glove dyeing, 303 
 Animals' skins, classification of, 28 
 Anopterus glandulosa, 86 
 Antiferments, 151 
 Antigalline, 67 
 Apricot-bark, 54 
 Arabic gum, 340, 439 
 Arctium lappa, 49 
 Arctostaphilos uva ursi, 84 
 Areameter, Connolly's, 430 
 Areca catechu, 84 
 Areolar tissue, 23, 26 
 Argol bath, 175 
 Aim-stake, 342 
 
 board, 382 
 Arnica montana, 49 
 Arok kenema, 84 
 Arrasa, 84 
 
 Arsenic limes, depilation by, 329, 330 
 Artificial tannin, 55 
 Aru mata, 84 
 Asacum, 84 
 Ash-bark, 54 
 
 ley, 276 
 
 soda. 234 
 Ashes, wood, 219, 253 
 Ashing, 253 
 Asphodel plant, 47 
 Asiidospermum quebracho, 77, 86 
 
 Ass and mule hides, 38 
 Asses' skins, 439 
 Atherospernia moschata, 86 
 Avens root, 53 
 Avicennia nitida, 84 
 Avicennica tormentosa, 86 
 
 BABOOL, 84 
 Badvil and Lienders' process for 
 preparing tannic acid, 47 
 Balsamo, 84 
 Ballatschano and Trenk's process, 
 
 174 
 Banksia australis, 85 
 Baramalli, or pump wood, 84 
 Barium, chloride of, 263 
 Bark, alder, 54, 87 
 
 apricot, 54 
 
 ash, 54 
 
 beech, 54 
 
 birch, 54 
 
 cinchona, 49 
 
 common willow, 21 
 
 cork-iree, 72 
 
 elm, 54 
 
 examination of, 89 
 
 extract of, 245 
 
 grinding tbe, 237 
 
 harvesting, 72 
 
 hazel, 54 
 
 horse chestnut, 49 
 
 iron, 85 
 
 kermes oak, 85 
 
 larch, 54 
 
 mills, 405 
 
 mimosa, 54, 83 
 
 oak, 21, 68, 143 
 tanning, 143 
 
 old oak, 53 
 
 sassafras, 54 
 
 sycamore, 54 
 
 willow, 54 
 
 winter's, 55 
 
 young oak, 53 
 Barking of trees, 71 
 Barkometer, 90 
 Barks, 68 
 Barley, 294 
 
 dressing, 294 
 Barley-meal, 294 
 
 bating with, 141 
 Baron's process of quick tanning, 219 
 Basic sulphate of iron, 261 
 Basils, 39, 414, 435 
 
 oak-tanned, 435 
 Bate or grainer, 139 
 
 sulphuric acid, 141 
 
464 
 
 INDEX. 
 
 Bath dyeing, 301 
 
 sumac, 388 
 Bating, 139, 225, 332 
 
 lactic acid for, 142 
 
 Turnbull's process, 141 
 
 with bailey-mtal, 141 
 
 Warrington's process, 141 
 Battery, 48 
 
 Beabejum stellatum, 84 
 Beam, 124, 369 
 
 fleshing on the, 283 
 
 house, 124 
 
 knife, French, 236 
 German, 236 
 
 unhairing on the, 124 
 
 work, 236 
 
 working on the, 124 
 Beamsman or shaver, 375 
 Bearberry, 84 
 
 Beck's process of depilation, 136 
 Bell Stephens' method of estimating 
 
 tannin, 92 
 Bell's process of quick tanning, 
 
 219 
 Belt leather, 33 
 
 or crop leather, 226 
 Bengal catechu, 53, 75 
 Bennet, berb, 17 
 Benzine, 263 
 Benzol, 454 
 Berzelius' process for preparing tannic 
 
 acid, 44 
 Betel, 84 
 Betula alba, 84 
 Betuline, 282 
 
 Bez and Sons' process, 8, 192 
 Bichromate of potash, 266 
 Birch, 84 
 
 bark, 54 
 
 oil, distillation of, 282 
 
 oil of, 282 
 
 tar oil, 265 
 Bisulphide of calcium, depilation by, 
 
 132 
 Bitartrate of potash, 175 
 Black dye, 300, 339 
 
 for chrome leathers, 339, 340, 
 353 
 
 glace manufacture, 327-344 
 
 grain, high shoes, 396 
 Kussia leather, 281 
 
 vegetable, 297 
 wattle, 84 
 
 wood, 84 
 Blackthorn, 54 
 
 Blacking and setting for currying, 
 390 
 
 Bleaching leather, 269, 362 
 
 processes, American, 270 
 Blocking boot-fronts, 397 
 
 machine, 397 
 Blood wood, 84 
 Bloom, 413 
 Blue dye, 300 
 
 galls, 73 
 
 gum, 84 
 
 Prussian, 297 
 
 Saxon, 300 
 Blue-backing, 337, 351 
 Blueing, iron tannin, 13 
 Blunt tool, 110 
 Boa constrictor, 432 
 Bohemian olive, 54 
 Boiler, tan-burning, 455 
 Bombay catechu, 21, 53, 75 
 Bombax malebarica, 85 
 Bone gelatine, 452 
 Boomah, 84 
 
 Boot-fronts, blocking, 97 
 Borate of zinc, 264 
 Bot, or gadfly, 31 
 Bottles, skm, 5 
 Bottom sizes, 383, 384 
 Bouillon-Legrange's process for pre- 
 paring tannic acid, 45 
 Bourdon scourer, 155, 413 
 Bower, 343 
 
 Box-calf, manufacture of, 348-350 
 Brain's process for soitining dried 
 
 hides, 111 
 Bran drench, 308, 316 
 
 dressing, 296 
 
 liquor, 296 
 
 steep, 318 
 Branding, 31 
 Branning, 308 
 Brazil wood, 277 
 Breakers, 309 
 Breaking, 307 
 Brined hides, 37 
 Brokers, buyers', 373 
 Brown soap, 391 
 Brysonima, 85 
 Bucida buceras, 84 
 Buck skin dressing, 366 
 
 tallow, 396 
 Buff leather, 38, 363 
 
 machine, 390 
 
 process, 363 
 Buffalo hides, 38 
 Buffs, polishing, 38 
 Burbidge's tanning process, 203 
 Burette, 94 
 Butea frondosa, 76, 84 
 
INDEX. 
 
 465 
 
 Buteagum, 53 
 
 kino, 84 
 
 superba, 85 
 Butt, 28, 126 
 
 dressing, 388 
 
 kip, setting machine, 380 
 
 tanning, 143 
 Butts, tanning for sole leather, 
 143 
 
 currying kip, 373 
 
 drying the tanned, 156 
 
 sole, 406 
 Buyers' brokers, 373 
 
 p^ESALPINIA, 86 
 v^ Toriaria, 84 
 
 Calcei mullei, Roman, 6 
 Calcium, oxide of, 117 
 
 bisulphide of, 132 
 Calf kid, 311 
 
 drying, 317 
 for uppers, 314 
 
 skins for uiemel, 295 
 fawing, 317 
 
 one- and two- bath methods 
 for, 348 
 Calves' skins, 38 
 Camata, or camatina, 81 
 Camel skin, 440 
 Cape lambskins, 435 
 
 sheepskins, 435 
 Carapa guianensis, 84 
 Carbolic acid, 67, 343 
 Carbonate of ammonia, 45 
 lead, 45 
 lime, 117 
 potash, 46 
 Carpenters' glue, 456 
 Carpnn brevifolium, 84 
 Casali's process, 10!) 
 Cascara, 84 
 Cashew, 74 
 
 Cassia, 49 ; auriculata, 86 
 Castanea vesca, 84 
 Casuarina quadrivalvis, 86 
 Catechine, 75 
 Catechu, 17, 84 
 
 acacia, 74 
 
 analysation of, 75 
 
 Bengal, 53, 75 
 
 Bombay, 21, 75 
 
 Indian, 75 
 
 Malabar, 75 
 
 Peru, 53 
 Catechu-tannic acid, 14 
 Cattchuic acid, 75 
 
 2 
 
 Catgut, 447 
 
 Cattle intestines, preparation of, Con- 
 tinental method, 441 
 Caustic alkali, 52 
 lime, 115 
 
 soda, depilation by, 131 
 Celery pine, 84 
 Centauria cyanus, 49 
 Cevil, 84 
 
 Chamois glove leather, 362 
 leather, 39, 357, 361, 363 
 imitation, 40 
 manufacture, 357-303 
 Charcoal, depilation by, 133 
 
 skins, colouring, 362 
 Checking or preventing gallic fermen- 
 tation, 64 
 Chemical methods of estimating tan- 
 nin, 91 
 tanning, 260 
 
 Heinzerling's process, 262, 
 ^ 263, 324 
 
 Knapp's processes, 261, 324 
 Schultz's process, 324 
 Vanderstraaten's process, 
 
 266 
 theory of, 11 
 Chcnopodium, 440 
 Cherry-tree, 84 
 Chestnut, 84 
 
 extract, 77 
 Spanish, 21 
 Chinese nut-galls, 53 
 Chloride of barium, 263 
 
 potassium, 191 
 sodium, 263 
 sulphur, ^265 
 tin, 46 
 zinc, 264 
 Chlorine, 24, 97 
 Chromate of alumina, 175 
 magnesia, 263 
 potash, 262 
 soda, 262 
 Chromates, soluble, 262 
 Chrome leather dyeing, 336, 338, 344- 
 347 
 history and technique, 323 
 manufacture, 323-347 
 
 machinery, 415, 419- 
 
 430 
 trade revolutionized 
 by, 323, 400 
 liquors, 334, 349, 350 
 tanning, 334, 349 
 Chrome-oxy chloride, 349 
 Chroming operations, 334 
 
 II 
 
466 
 
 INDEX. 
 
 Chrome processes, Heinzerling's, 2(52, 
 263 
 Schultz's, 324 
 
 process, popularity of, 372 
 
 industr}'', 385 
 Chromic acid, 263 
 
 tannage, principle of, 324 
 Chrysene, 263 
 Cinchona bark, 49 
 Cinnamon, 49 
 Classification of sheepskins, 435 
 
 skins of animals, 28 
 Cleansing and washing hides, 224 
 
 raw hides, 109 
 Clearing stone, 369 
 Clove, 444 
 Cloves, 55 
 Coal-tar dyes, 300 
 Coccoloba uvifera, 86 
 Cochineal, 289 
 Cod oil, 378, 383, 384 
 Coecum, 444 
 Coez's process for preparing tannic 
 
 acid, 47 
 Cold sweating, 129 
 
 of hides, 231 
 Colophony, 265 
 Colouring chamois skins, 362 
 Colours, analine, dyeing with, 300, 
 337, 345, 346, 354 
 in glove dyeing, 303 
 
 pure aniline, dyeing with, 304 
 Columbian kino, 76 
 Compo, 348 
 Composition, 396 
 
 for tanning, 253 
 
 of the skin, 27 
 Common willow-bark, 21 
 Condition of hides and skins, 28 
 
 of raw hides, 108 
 Connolly's areameter, 432 
 Continental method of liming, 120 
 
 method of preparing cattle intes- 
 tines, 441 
 
 method of preparing glove-lea- 
 ther, 313 
 
 successful use of corichrome, 
 . 346 
 Conveyors, 161, 406 
 Copal varaish, 298 
 Copperas, 51, 300 
 Copper filings, 440 
 
 sulphate of, 264 
 
 vitro] of, 305, 353, 354 
 Coppice oak, 70 
 
 Copying crocodile and alligator skins 
 by electrotype, 432 
 
 Cordova leather, 288 
 
 Cords, lathe, 444 
 
 Cords for tennis bats, &c, 446 
 
 from sheep intestines, 445 
 Coriaria myrtifolii, 79 
 
 ruscifolia, 86 
 Corichrome mordants, 346 
 Corin, 350 
 
 Corium, or true skin, 23 
 Cork-tree, 84 
 
 bark, 72 
 Cornus sanguinea, 54 
 Cortex, 89 
 
 Corrosive sublimate, 65 
 Cost of tanning, Schultz on the, 272 
 Cotswold sheepskins, 435 
 Count Kartstoff's description of 
 
 Russian leather manufacture, 277 
 Couruda, 84 
 Cowhides, split, currying, 396 
 
 for brown bags, 396 
 Cox's tanning process, 198 
 Crab wood, 84 
 Cream of lime, 436 
 Crepida, Roman, 6 
 Crocodile and alligator skins, 431 
 
 copying by electrotype, 432 
 
 and serpent skins, 42 
 Crocoxylon excelsum, 86 
 Crop leather, 226 
 Cross-grained roller, 396 
 Crosse's process of tanning bv electri- 
 city, 258 
 Crust goods, 317 
 Crutch stake, 317 
 Crystallised verdigris, 439 
 Cube gambier, 77 
 Curmpuay, 84 
 Currying, 368 
 
 calf-skins for mem el, 395 
 
 composition for stuffing. 379. 
 380 
 
 kip leathers, 371 
 
 levant leather, 392 
 
 preparation of size for, 383, 384, 
 385 
 
 satin or glove shoe leather, 385, 
 391 
 
 shop, 369 
 
 split cow-hides, 396 
 
 various leathers, 395 
 
 waxed calf-skins, 395 
 Curriers' knife, 317, 370 
 Cutch, 74, 81 
 Cuticle, 11, 23, 26 
 Cutis, 11, 23, 26 
 
 vera, 23, 26 
 
INDEX. 
 
 467 
 
 Cutting (glue boiling), 450 
 Cuyama, 84 
 Cynips, 43, 73 
 
 DANISH quick tanning process, 221 
 Davy, Sir H., on Segu.n's theorv, 
 19 
 Davj T , Dr., on the action of lime on 
 
 animal matter, 121 
 Davy's method of estimating tannin, 
 
 92 
 Dead Sea apples, 73 
 
 vat, 120 
 De Bock's tanning process, 196 
 Deer skins, 41 
 
 tallow, 396 
 De?ras«.337, 379, 352 
 Dehairing, 115, 329, 330 
 De-liming, 332 
 agents, 332 
 Dennis's tanolin, 349 
 Dentelaria, 84 
 
 Depilation, Beck's process, 13G 
 by acids, 129 
 
 arsenic limes, 329, 330 
 bisulphide of calcium, 132 
 caustic soda, 131 
 charcoal, 133 
 lime, 115, 329, 330 
 machinery, 402 
 saccharine matter, 131 
 sulphide of sodium, 133, 330 
 or unhairing skins and hides, 115 
 Palmer's process, 134 
 by sweating, 128 
 De mood's tanning process, 202 
 Determination of tannin by specific 
 
 gravity, 89 
 Dextrine, 303 
 Deyeux's process of preparing tannic 
 
 acid, 46 
 Dialysis, 49 
 
 Dietz's process of quick tanning, 217 
 Diospyros glutinosa, 85 
 Diplolepsis, 43 
 Disintegrators, 405 
 Distillation of birch oil, 282 
 Divi divi, 54, 82, 84 
 Dize's process for preparing tannic 
 
 acid, 45 
 Dog-skin gloves, 435 
 wood berry, 303 
 Donzeri sumach, 79 
 Doomboom, 84 
 
 Drake's tanning process, 8, 207 
 Drawing off the liquor (glue-boiling), 
 450 
 
 Drench, bran, 308, 316 
 Drenching, 307, 316, 358 
 Dressing, alum, 307, 314, 317 
 
 barlev, 294 
 
 bran, 296 
 
 buck skin, 366 
 
 red, 295 
 
 white, Morfit's remarks on, 
 295 
 Dressing leather, 410 
 Dried hides, 30, 110 
 
 softening, 110 
 
 salted hides, 31 
 Drumheads, skins for, 439 
 Drum-stuffing, 377, 378 
 materials, 378 
 tumbler, 375, 377 
 Dr. Ure's Views on quick tanning, 
 
 213 
 Dry distillation, 282 
 
 salted hides, 112 
 Dryinsr, 310, 317 
 
 black, 339 
 
 calf skins, 317 
 
 (glue-boiling), 451 
 
 (gut-dressing), 443 
 
 loft, 157 
 
 oil, 297 
 
 the tanned butts, 156 
 Dubbin, 377, 384 
 
 Duplex unhairing and fleshing ma- 
 chine, 315 
 Dussauce on Seguin's theory, 10 
 Dussauce's observations on quick tan- 
 ning, 215 
 Dust, emery, 387 
 Dve, black, 300 
 
 blue, 300 
 
 calf-skins, 353 
 
 goat skins, 339 
 
 green, 300 
 
 olive, 300 
 
 puce, 300 
 
 red, 299 
 
 sulfamine, 345 
 
 violet, 300 
 
 yellow, 300 
 Dyeing, 318 
 
 aniline colours in glove, 303 
 
 bath, 301 
 
 chrome leather, 336 
 
 fancy shades, 344 
 
 glove-leather, 303 
 
 kid-leather, 300 
 
 leather, 299 
 
 Morocco leather, 299 
 
 on a flat surface, 302 
 
458 
 
 INDEX. 
 
 Dyeing, with aniline colours, 300, 
 337, 345, 346, 354 
 logwood and hemolin, 337 
 pure aniline colours, 304 
 
 Dyes, coal-tar, 300 
 
 EAST India kips, 37, 392 
 Egging, 309, 318 
 Elaeocarpus dentatus, 85 
 Elder, 54 
 Elderberry, 303 
 Electricity, tanning by, 254 
 
 tanning by, Crosse's process, 258 
 
 Gaulard's processes, 255, 256 
 
 Meriten's process, 257 
 
 Ward's process, 254 
 
 Electrotype, copying crocodile and 
 
 alligators' skins, &c, by, 432 
 
 copper rollers, 432 
 
 process, 431 
 Elk skins, Indian method of pre- 
 paring, 268 
 Ellagic acid (bloom), 62, 413 
 Elm-bark, 54 
 Emblica officinalis, 81 
 Embossed leather, 7, 430 
 Embossing leather, 393. 430 
 
 machines, 414, 431, 433 
 Emery dust, 387 
 Emulsion or paste, 309 
 Enamelled leather, 293 
 English oak, 70 
 Eosine, 302 
 Epidermis, 18, 23, 89 
 Epsom salt-<, 196 
 Erodin, 332 
 Erythrosine, 303 
 Essence of turpentine, 181 
 Estimation of tannin, 88 
 
 Bell Stephens' method, 92 
 
 by barkometer, 90 
 
 by chemical methods, 91 
 
 Casali's process, 103 
 
 Davy's method, 92 
 
 determined by specific gravity, 
 89 
 
 Hammer's method, 93 
 
 Lovventhal's method, 94 
 
 Mr. Hewitt on Lowenthal's me- 
 thod, 97 
 
 Procter on do., 100 
 
 Eamspacker's method, 102 
 Eucalyptus globulus, 84 
 
 resinifera, 76, 85 
 
 leucoxylon, 87 
 Eugenia, maire, 86 
 Examination of bark, 89 
 
 Exocarpus cupressiformus, 84 
 Extinction of wax leather, 372 
 Extract, chestnut, 77 
 
 hemlock, 77 
 
 Hungarian larch, 77 
 
 larch, 77 
 
 mangrove, 80 
 
 oakwood, 77, 377 
 
 of bark, 245 
 
 quebracho, 77 
 Extractive, 18, 213, 222 
 Extracts, tanning, 74 
 
 TRAGUS CUNNINGHAMI, 85 
 -L Menziesii, 86 
 
 Fat-liquoring chrome leather, 337, 
 
 345, 351 
 Fat-liquors, 337, 338, 362, 363 
 Feeding of leather, 20, 214 
 
 the skin, 149 
 Fellmongered, 287 
 Fellmongering, 434 
 Fellmongers, 287 
 Fells, 287 
 Fermentation, ascetic, 142 
 
 acetous, 205 
 
 putrefactive, 128 
 
 putrid, 442 
 Ferric acetate, 14 
 
 salts, 14 
 
 sulphate, 14 
 Fibrilke, 25 
 Fibrm, 17, 18 
 Fig bath, 288 
 Filandre, 446 
 Finishing, 381 
 
 chamois, 361 
 
 glazed kid, 341 
 
 machinery, 406, 423 
 First boiling (glue), 449 
 
 English patents for tanning, 169 
 Fish, dog, 345 
 
 glue, 446 
 
 oil, 311 
 
 shagreen, 440 
 
 skin, or fish shagreen, 440 
 Flaming, 291 
 Fleshing, 124 
 
 and unhairing, 283 
 
 by machinery, 315, 331, 404 
 
 knife, 115, 125 
 
 on the beam, 283 
 Flesh splits, 289 
 Flint hides, 30, 110 
 Formic acid for bating, 142 
 French beam-knife, 236 
 
 glue, 452 
 
INDEX. 
 
 469 
 
 French kid gloves, 41 
 leather, 310 
 tannage, 383 
 French metrical or decimal measures 
 of length, 460 
 metrical or decimal measures of 
 volume, 460 
 Frizing, 358 
 Fronts, boot, 397 
 
 Fryer, Watt, and Holmes's tanning- 
 process, 209 
 Fucus crispns, 266 
 Fuller's earth, 297 
 Fulling stocks, 110 
 Funcke's tanning process, 197 
 Fusarmis compressus, 85 
 Fustic %ood, 339 
 
 GALL-NUTS, 43 
 Galls, 21, 85 
 Aleppo, 53 
 blue, 73 
 Chinese, 53 
 decoction of, 57, 58 
 green, 73 
 infusion of, 59 
 Istrian, 53 
 large Mecca, 73 
 nut, 73 
 tamarisk, 86 
 white, 73 
 GalliB tinctorum, 43 
 Gallic acid, 14, 18, 57 
 
 preparation of, 58 
 Dumas' method, 58 
 Graham's method, 58 
 Liebig's method, 58 
 pharmaceutical method, 59 
 properties of, 60 
 Scheele's method, 58 
 fermentation, 63 
 
 prevention of, 64 
 Gallo-tannic acid, 43 
 
 tannin, 15 
 Gambier, or terra japonica, 53, 77, 85 
 
 and sumac liquor, 377 
 Gauh, 85 
 Gaulard's processes of tanning by 
 
 electricity, 255, 256 
 Gelatine, 11, 91 
 
 action of tannic acid on, 13 
 bone, 452 
 properties of, 11 
 sugar, 12 
 Gelatinising (glue -boiling), 450 
 Gelatinous tissue, 27 
 Geranium maculatum, 77, 85 
 
 German beam-knife, 236 
 Geum urbanum, 49 
 Glace goatskins, 327 
 
 finishing, 341 
 
 kid, 327 
 
 leather, 310, 318, 323 
 Glass hydrometer, 91 
 Glazed kid, finishing, 311 
 Glazing, 394 
 
 box-calf, 356 
 
 chrome leather, 343 
 Glecoma hederacea, 49 
 Glossing (glue-boiling), 449 
 Glove-leather, 387 
 
 chamois, 362 
 
 Continental method of prepar- 
 ing, 313 
 
 dyeing, 303 
 
 hide, 386 
 Gloves, dog-skin, 435 
 
 French kid, 41 
 Glue-boiling, 449 
 
 carpenter's, 456 
 
 fish, 446 
 
 French, 452 
 
 parchment, 453 
 
 pieces, treatment of, 449 
 
 waste, 452 
 Glucose in leather, 459 
 Gmelin on the action of tannic acid 
 
 on gelatine, 13 
 Goat-skins, 40, 327, 328 
 
 glace, 327-344 
 
 d.veing fancy shades, 314 
 
 one- and two- bath methods for, 
 326, 327 
 
 Patna, 328, 419 
 
 Swiss, 40 
 Goldbeaters' skin, 444 
 Graham's method of preparing gallic 
 
 acid, 58 
 Grain leather, 386 
 
 splits, 288 
 Graining, 382 
 
 after whitening, 382 
 
 board, hand, 382 
 Grape sugar, 458 
 Green dye, 300 
 
 galls, 73 
 
 hides, 29 
 
 splitting, 411 
 
 luminere, 304 
 
 oak, 85 
 
 sheepskins, 242 
 
 vitriol, 261, 305 
 Greening, tannin, iron, 13 
 Grinding the bark, 237 
 
47o 
 
 INDEX. 
 
 Grounding, 818 
 
 Guest and Court's process, 456 
 
 Uuiot's process of quick tanning, 
 
 221 
 Gum arabic, 340, 439 
 Gut-dressing, 441 
 
 strings for musical instruments, 
 446 
 
 HAIR- WASTE, 457 
 Hauler's tanning process, 197 
 Hammer's method of estimating tan- 
 nin, 93 
 Hand-graining board. 382 
 press, 433 
 reel, 235 
 roller, 166 
 Handler liquor, 147 
 the rocker, 243 
 Handlers, 147 
 Handling, 148, 242 
 Hard leather, tanning process for, 
 
 181 
 Harness and upper leather, manu- 
 facture of, 223 
 leather, 223 
 Harvesting bark, 72 
 Hazel bark, 54 
 Heinzerlmg's chrome processes, 262, 
 
 263, 324 
 Hemlock, 54, 85 
 extract, 77 
 
 lime rough leather, 272 
 sweat sole leather, 272 
 tannage, 389 
 tanning, 245 
 
 Hibberd's process of, 252 
 of New Lebanon, N.J., 249 
 Hemolin and logwood, dyeing with, 
 
 337 
 Hcmpseed, 218 
 Herb bennet, 17 
 Hcrse, 437 
 Hewitt on ■ Lowenthal's method of 
 
 estimating tannin, 97 
 Hibberd's process of hemlock tan- 
 ning, 252 
 Hide and skin cuttings, 456 
 glove, 386 
 hook, 119 
 ox, 28 
 
 splitting machine, 328, 375 
 Hides, 28, 29 
 
 and skins, 27 
 
 depilation of, 115 
 condition of, 28 
 
 Hides, ass and mule, 38 
 brined, 37 
 buffalo, 37 
 
 cold sweating of, 229 
 cow, 226 
 
 split, for brown bags, 396 
 dried, 30, 110 
 
 Brain's process for soften- 
 ing, 111 
 salted, 31 
 softening, 110 
 dry, salted, 112 
 Hint, 30, 110 
 green or fresh, treatment of, 108 
 
 splitting, 411 
 hippopotamus, 38 
 horse, 38 
 
 tawed, 38 
 imported, 109 
 infected, 271 
 method of sailing, 109 
 native, 30 
 ox, 38 
 
 raw, cleansing, 109 
 condition of, 108 
 stocking, 400 
 salted, 30 
 Schultz's views on the treatment 
 
 of, 112 
 selection of, 223 
 treatment of, after sweating, 231 
 
 of, in sweat pits, 230 
 walrus, 38 
 weight of, 30 
 wet salted, 112 
 High shoes, black grain, 390 
 Hinan, 85 
 
 Hippopotamus hides, 8S 
 Hog and pig skins, 41 
 plum, 85 
 skins, 41 
 Holm-tree, 85 
 Honeysuckle, 85 
 Hops, 218 
 Horse, the, 104 
 bot, 33 
 
 chestnut bark, 40 
 hair, 446 
 hides, 38 
 
 tawing, 38 
 Housings, 39 
 Huldi, 85 _ 
 Human skin, 24 
 Hungarian larch extract, 77 
 Hungary leather, 290 
 Hydrate of lime, 117 
 Hydraulic press, 377, 453 
 
INDEX. 
 
 47i 
 
 Hydrochloric acid, 45, 95, 325 
 
 chrome oxide, 849 
 Hydrogen, sulphuretted, 46 
 Hydrometer, 89 
 
 glass, 91 
 Hydrostatic pressure, tanning by. 
 
 206 
 Hygrometer, 158 
 
 Mason's, 158 
 Hyposulphite of soda, 324 
 
 TLLUSTRATION of the skin, 86 
 -L Imitation chamois leather, 40 
 
 kid, 312 
 Imitation Morocco leather, 287 
 
 pigskin, 414 
 Imported hides, 119 
 Indian catechu, 75 
 Indigo blue, 95 
 
 carmine, 97 
 Induline, 304 
 
 Inflation (gut dressing), 443 
 Influence of light on leather, 161 
 Infusion of galls, 96 
 
 oak-bark, 96 
 
 sumach, 96 
 Instruments, musical, gut strings for, 
 446 
 
 stringed, 447 
 Intestines, cleansing, 447 
 
 sheep, cords from, 445 
 
 treatment of, 447 
 Iris pseudacorus, 49 
 Irish, old, process of tanning, 268 
 Iron, acetate of, 281 
 
 bark, 85 
 
 basic sulphate of, 261 
 
 blueing acids, 14 
 tannin, 13 
 
 oxide salt, 261 
 
 persalts of, 13 
 
 persulphate of, 13 
 
 protosulphate of, 51 
 
 sesquichloride of, 52 
 
 sesquioxide of, 264 
 
 soap, 261 
 
 sulphate of, 264 
 
 tannate of, 51 
 Isinglass, 11 
 Istrian nut galls, 33 
 
 JAMAICA kino, 75 
 *) Japan earth, 77 
 
 leather, 298 
 Jennings' tanning process, 174 
 
 KAOLIN, 100 
 Kararalli, 85 
 Kartstoff's description of Russia lea- 
 ther manufacture, 277 
 Kassu, 85 
 
 Keasley's tanning process, 182 
 Kermes oak, 85 
 
 bark, 53 
 Kettledrums, 439 
 Kid butt-setting machine, 380 
 calf, for uppers, 314 
 glazed, finishing, 341 
 imitation, 312 
 leather, 307 
 
 currying, 371 
 dyeing, 300 
 French, 300 
 skins, 40 
 
 treatment of, 307 
 Kino, or gum kino, 49, 76, 85 
 Amboyna, 75 
 Columbian, 76 
 Jamaica, 75 
 Kip-skins, 113 
 
 butts, currying, 373 
 offal, 386 
 Kips, 28, 37, 861, 373 
 
 East India, 37, 392 
 Kleman's tanning process, 204 
 Knapp's process of chemical tanning, 
 261 
 chrome process, 324 
 Knife, beam, French, 236 
 curriers' 317, 370 
 fleshing, 125 
 moon, 318 
 rounding, 127 
 shaving:, 371 
 unhairing, 124 
 Knoppern, 85 
 
 Knowlys and Duesbury's tanning pro- 
 cess, 208 
 Kohlrausch's process for preparing 
 
 tannic acid, 48 
 Krameria triandri.i, 79, 86 
 Krameric acid, 80 
 Krupelboom, 85 
 Kullaballi, 85 
 
 LAMBS' skins, 39 
 Lamium album, 49 
 Lampblack, 383, 395 
 Lange, on the abusive treatment of 
 
 hides, 35 
 Larch, 85 
 
 bark, 54 
 extract, 77 
 
472 
 
 IXDEX. 
 
 Large Mecca galls, 73 
 Larix americana, 85 
 
 europsea, 85 
 Lathe cords, 444 
 Laurus sassafras, 80 
 Layer liquor, 71 
 Layers, the, 149, 243 
 Laying the grain, 155 
 Leaches, 146 
 Leaching, 238 
 Lead, carbonate of, 45 
 Leather, American trade in, 372 
 belt, 38 
 bleaching, 269 
 buff, 38, 363 
 
 process, 363 
 chamois, 39, 357, 361, 363 
 colouring, 362 
 glove, 362 
 
 manufacture, 357-363 
 chrome, manufacture, 323-347 
 
 Schultz's patent, 324 
 cloth, American, 267 
 Cordovan, 2, 288 
 crop or belt, 226 
 currying kip, 371 
 dressing, 410 
 
 machinery, 410-412 
 dyeing, 299 
 embossed, 7 
 embossing, 431 
 enamelled, 297 
 extinction of wax, 372 
 feeding of, 20, 214 
 French kid, 310 
 glace, 310 
 glove, 387 
 
 Continental method of pre- 
 paring, 313 
 dyeing, 303 
 glucose in, 459 
 goat-skin, 327 
 grain, 382, 386 
 
 hard, tanning process for, 181 
 hemlock tanned, 245 
 sweat sole, 272 
 Hungary, 290 
 imitation chamois, 40 
 
 Morocco, 287 
 influence of light upon, 161 
 Jamaica, 298 
 Japan, 298 
 kid, 307 
 
 dyeing, 300 
 Levant, 392 
 machine-buffed, 390 
 Madras, 374 
 
 Leather, manufacture of harness and 
 upper, 223 
 manufacture, machinery em- 
 ployed in, 399-430 
 Morocco, 2, 282 
 dyeing, 299 
 oak lime, 272 
 oiled, 394, 435 
 ornamental, 42 
 ornamenting, 431 
 patent, 297 
 preservative, 328 
 red Morocco, 299 
 rolling, 165 
 rough, hemlock lime, 272 
 
 oak lime, 272 
 Russia, 276 
 
 another method of prepar- 
 ing, 279 
 black, 281 
 
 manufacture, Count Kart- 
 stoff's description of, 
 277 
 shagrin, 2, 38 
 shammy, or shamoy, 39 
 sheep, white, 318 
 skiver, 288, 322, 356 
 smoke-cured, 5 
 soaking the, 374 
 soft, tanning process for, 181, 
 
 374 
 softening the, 374 
 tanning butts for sole, 143 
 tawed, 317 
 to determine when tanned 
 
 throughout, 167 
 union lime sole, 272 
 vegetable, 265 
 vitriol-raised, 241 
 Wallachia, 291 
 wax, 372, 396 
 waxed, 372, 374, 383 
 white, manufacture of, 306 
 Yuf ts, or Russia, 281 
 Leather-making revolutionized by 
 
 chrome power, 323, 400 
 Leathers, currying various, 395 
 light, manufacture of, 276 
 Leaven, 294 
 Lecythis ollaria, 85 
 Leicester sheepskins, 435 
 
 willow, 21 
 Leucine, 12 
 
 Leucospermum conecarpum, 85 
 Ley, ash, 276 
 Leys, potash, 447 
 Liber, 69 
 
INDEX. 
 
 473 
 
 Liebig's method of preparing gallic 
 
 acid, 58 
 Light leathers, manufacture of, 276 
 Lignin, 72 
 Lignum vita?, 369 
 Lime, acetate of, 308 
 
 arsenic, 829, 330 
 
 carbonate of, 117 
 
 caustic, 115 
 
 cream of, 436 
 
 depilation by, 115, 329, 330 
 
 Dr. Davy on the action of, on 
 animal matter, 121 
 
 hydrate of, 117 
 
 middle, 315 
 
 milk of, 115, 449 
 
 process, 115 
 
 supposed disadvantages of, 
 121 
 
 properties of, 117 
 
 saccharate of, 141 
 
 storing the, 118 
 
 sulphuret of, 132 
 
 tannate of, 16, 71 
 
 waste, 458 
 Lime-water, 45 
 Limestone, 117 
 Liming, 118, 224, 307, 329 
 
 and soaking, 315 
 
 Continental method of, 120 
 Lincoln sheepskins, 435 
 Linseed oil, 265 
 Liquor, bran, 296 
 
 logwood, 385 
 
 oak -bark, 269 
 List of tanning materials, 84 
 Lithrum salicaria, 49 
 Live vat, 120 
 Loft or shed, drying, 157 
 Logwood and hemolin, d3 - eing with, 
 
 327 
 Lomas' tanning process, 176 
 Lombardy poplar, 54 
 Lowenthal's method of estim- ting 
 tannin, 94 
 
 Hewitt on, 97 
 Procter on, 100 
 Lumiere green, 304 
 Lupkin's unhairing process, 233 
 
 MACHINE, hark mills, 404 
 blocking, 397 
 buffing, 417 
 buff leather, 390 
 butt-stretching, 425 
 depilating and fleshing, 402, 421 
 disintegrating, 405 
 
 Machine, embossing, 414, 431-433 
 Huxham & Brown's, 431, 
 the Altura, 431 
 fleshing, 315 
 fluffing, 426 
 glazing, 427 
 kip butt-setting, 380 
 measuring, 429, 430 
 
 Connolly's areameter, 430 
 printing, 433 
 rolling, 166, 409 
 scouring, 155, 413 
 scudding, 422 
 setting, 414 
 shaving, 375, 410 
 softening, 416 
 splitting, 320, 375, 411 
 staking, 425, 426 
 stocking, 400 
 striking, 164, 406 
 stuffing, 415 
 
 unhairing and fleshing, 419 
 Duplex, 315 
 Machinery employed in leather manu- 
 facture, 399-430 
 
 embossing, 414, 431-433 
 sole leather tanning, 400-419 
 unhairing and fleshing by, 315 
 used in chrome leatber manu- 
 facture, 415, 419-430 
 Madder, 219 
 Madras leather, 374 
 Magnesia, chromate of 262 
 
 tannate of, 71 
 Mala insana, 73 
 Malabar catechu, 75 
 Malic acid, 65 
 Manganese, oxide of, 264 
 
 sulphate of, 264 
 Mangrove, 85 
 Manufacture of box-calf, 348-356 
 
 of chamois, or oil-leather, 357- 
 
 363 
 of chrome leather, 323-347 
 
 machinery, 415, 419-430 
 of harness and upper leather, 
 
 223 
 of leather, machinerv employed 
 
 in, 397 
 of light leather, 276 
 of white leather, 306 
 Marsh rosemary, 85, 86 
 Mason's hygrometer, 158 
 Materials, drum-stuffing, 378, 380 
 Measures and weights of the metrical 
 system, 460 
 
 of capacity, 461 
 
474 
 
 INDEX. 
 
 Measures, of length, 461 
 
 French metrical or decimal, 
 
 460 
 volume, French metrical or 
 decimal, 460 
 Measuring (gut dressing), 443 
 Memel, calf -skins for, 395 
 
 roller, 395 
 Me'ne, M., 269 
 Merat-Guillot's process for preparing 
 
 tannic acid, 45 
 Meriten's process of tanning by elec- 
 tricity, 258 
 Meta-gallic acid, 60 
 Methanil yellow, 302 
 Method of preparing Russia leather, 
 279 
 
 Bell Stephens', for estimating 
 
 tannin, 92 
 Continental, of preparing cattle 
 intestines, 441 
 
 of preparing glove-leather, 
 313 
 Davy's, for estimating tannin, 92 
 Hammer's, for estimating tan- 
 nin, 93 
 Indian, of preparing elk-skins, 
 
 268 
 Lowenthal's, for estimating tan- 
 nin, 94 
 of drying the tanned butts, Ame- 
 rican, 156 
 of estimating tannin, Hewitt on 
 Lowenthal's, 97 
 
 Procter on LowenlhalV, 100 
 Kampacker's, 102 
 of liming, Continental, 120 
 of salting hides, 109 
 single pit, 118 
 Methods of tanning, old, 144 
 
 in up-to-date leather works, 372 
 Methyl violet, 304 
 
 Metrical or decimal measures of 
 length, French, 460 
 
 of volume, French, 460 
 Michel, Kollen, and Hirtzog's pro- 
 cess, 176 
 Middle lime, 315 
 Milk of lime, 115, 449 
 Milling, 359, 364, 366 
 Mimosa, 85 
 
 bark, 54, 83 
 Miscellaneous processes, 268 
 Mixed tannages, 151 
 
 vitriol, 305 
 Mixture stuffing, 379, 380 
 Mochrus, 85 
 
 Modern system of tanning, 145 
 Mogadore skins, 40 
 Molina sumach, 79 
 Molle, 85 
 
 Moon-knife, 318, 342 
 Mora, 85 
 
 excelsa, 85 
 Mordants, 301, 337 
 
 corichrome, 346 
 Morfit's observations on tannin, 55 
 
 remarks on while dressing, 
 295 
 Moringa pterygosperma, 86 
 Morocco leather, 2, 282 
 
 dyeing, 299 
 
 imitation, 38, 287, 414, 432 
 
 red, 299 
 Mould, 156 
 Mouren's tanning process bv pressure, 
 
 209 
 Mr. Ashe's description of the skin, 
 
 24 
 Mucilage, 439 
 Muriate of tin, 191 
 Murici, 85 
 Musical instruments, gut strings for, 
 
 446 
 Mutton tallow, 440 
 Myrobalans, 54, 81, 85, 392, 405 
 Myrtle, 85 
 
 NAHRUNG, 313 
 Naphthaline, 203 
 
 yellow, 302 
 Napktkol yellow, 3U4 
 Native hides, 30 
 Neb neb, 85 
 Nectandra, 86 
 Needham's process of quick tanning, 
 
 218 
 Nets, sails and cordage, tanning, 
 
 265 
 New tanning materials, 86 
 Newton's tanning process, 170 
 Nigrosine, 304 
 Nilrate of soda, 262 
 Nitric acid, 55, 261 
 Nossiter's tanning process, 198 
 Nuessly's process of quick tanning, 
 
 218 
 Nut-galls, 15, 73 
 
 Aleppo, 53 
 
 Chinese, 53 
 
 Istrian, 53 
 Nutmeg, 444 
 Nymphaja alb.i, 49 
 
INDEX. 
 
 475 
 
 OAK, 85 
 bark, 21, 69, 143 
 
 infusion, 98, 278 
 tanning with decoction of, 
 265 
 
 coppice, 70 
 
 English, 70 
 
 kermes, 53 
 
 lime leather, 272 
 
 rough leather, 272 
 
 tanned basils, 435 
 
 valonia, 81, 405 
 Oakwood extract, 77, 377 
 Oatmeal, 278 
 Observations on the origin of warbles, 
 
 32 
 CEstrus bovis, 31, 34 
 Offal, 30 
 
 kip, 386 
 Oil, almond, 311 
 
 birch-tar, 265 
 
 cod-liver, 378, 383 
 
 cod, 383, 384 
 
 drying, 297 , 
 
 fish, 311 
 
 leather, 357 
 
 linseed, 394 
 
 neatsfoot, 337, 34.0 
 
 of birch, 281 
 
 of sesame, 289 
 
 of vitriol, 241 
 
 rape, 265 
 
 Russian, 281 
 
 sod, 360, 379 
 
 tanning, 357 
 
 thyme, 263 
 Oiled leather, 394, 435 
 
 buff leather, 435 
 
 chrome leather, 340 
 Old Irish process of tanning, 263 
 
 methods of tanning, 144 
 
 oak bark, 53 
 Olca europsea, 85 
 Olive, 85 
 
 dye, 300 
 On the cost of tanning, 272 
 One-bath method for calf-skins, 348 
 for goat-skins, 326 
 Ooze, 21, 146 
 
 preparation of, 146 
 Operation, tawing, 306 
 
 shaving, 375 
 Orach, wild, 3 
 
 Orgereau's tanning process, 173 
 Ornamental leather, 42, 431 
 Ornamenting leather, 431 
 Ovipositor, 32 
 
 Oxalic acid, 101, 301 
 Ox-bot, 33 
 
 gadfly, 33 
 Oxide of calcium, 117 
 
 of iron, salt of, 261 
 
 of manganese, 264 
 
 PAGE'S tanning process, 191 
 Palachy, 85 
 
 Palmer's process of depilation, 134 
 
 Paper-making, pulp for, from waste 
 tan, 455 
 
 Papyrus, 437 
 
 Paraffin, 265 
 
 Parchment glue, 453 
 
 and vellum, preparation of, 437 
 vellum and shagreen, 437 
 
 Parenchyma, 69 
 
 Parnell's views on tannic acid, 50 
 
 Paste, tawing, 313 
 
 Patent leather, 297 
 
 Patents for tanning, first English, 169 
 
 Pates, 231 
 
 Patna goat-skins, 328, 419 
 
 Pearlasb, American, 176 
 
 Pectin, 72 
 
 Pe'louze's process for preparing tannic 
 acid, 43 
 
 Pelt, 24 
 
 Pelts, rounding, 126 
 
 Pendulum roller, American, 167 
 
 Pseonia officinalis, 49 
 
 Percentage of tannin in vegetable sub- 
 stances, table of, 53 
 
 Pergamena, 437 
 
 Permanganate of potash, 94 
 
 Perones, Roman, 6 
 
 Persalts of iron, 13 
 
 Persian berries, 304 
 
 Persulphate of iron, 13 
 
 Peru catechu, 53 
 
 Pharmaceutical methods of preparing 
 gallic acid, 59 
 
 Phloxine, 302 
 
 Phosphoric acid, 301 
 
 Photogen, 263 
 
 Phylanthus emblica, 84 
 
 Phyllocladus asplenifolia, 84 
 trichomanoides, 86 
 
 Physiological uses of bark in plants, 
 69 
 
 Pickled skins (Australian and New 
 Zealand), 327 
 
 Pig and hog skins, 41 
 
 Pigskin, imitation, 414 
 
 Pinus excelepensis, 84 
 pinea, 86 
 
476 
 
 INDEX. 
 
 Pits, sweat, 229 
 
 treatment of hides in, 230 
 Plumbigo europaea, 84 
 Plum-tree, 54 
 Polishing buffs, 38 
 Polygonum amphibium, 86 
 
 bistorta, 49 
 Pomegranate, 54, 85 
 Popularity of chrome process, 372 
 Porpoise skins, 42 
 Porto sumach, 79 
 Potash, bichromate of, 266, 324 
 bitartrate of, 175 
 carbonate of, 46 
 chromate of, 263 
 leys, 447 
 
 permanganate of, 94 
 prussiate of, 262 
 tannate of, 71 
 Potassium, chloride of, 191 
 
 tun^state of, 264 
 Potentilla argentea, 49 
 
 reptans, 43 
 Poterium sanguisorba, 49 
 Pratt's system of tinning, 245 
 Preliminary operations, 108 
 Preparing elk-skins, Indian method, 
 268 
 
 gloveleather, Continental method 
 
 of, 313 
 the currier's knife, 317, 370 
 Preparation of cattle intestines, 441 
 of gallic acid from galls, 58 
 parchment and vellum, 437 
 size for currying, 383-385 
 tannic acid, Badvil and Lien- 
 
 ders' process, 47 
 tannic acid, Berzelius' process, 
 
 44 
 tannic acid, Bouillon -Le- 
 
 grange's process, 45 
 tannic acid, MM. Coez's pro- 
 cess, 47 
 taunic acid, Deyeux's process, 
 
 46_ 
 tannic acid, Dize''s process, 
 
 45 
 tannic acid, Kohlrausch's pro- 
 cess, 48 
 tannic acid, Merat-Guillot's 
 
 process, 45 
 tannic acid, Pe'louze's process, 
 
 43 
 tannic acid, Proust's process, 
 
 46_ 
 tannic acid, Schering's pro- 
 cess, 46 
 
 Preparation of tannic acid, Ser- 
 turner's process, 46 
 the blacking for currying, 390 
 the ooze, 146 
 " Press " leach, 239 
 
 hydraulic, 377, 453 
 Priego sumach, 79 
 Priestman's striker, 407 
 Principles of tanning, 7 
 Printing machine, 433 
 Process, Badvil and Lienders, for 
 preparing tannic acid, 47 
 Berzelius', for preparing tannic 
 
 acid, 44 
 Bez and Sons', for tawing, 8, 192 
 Bouillon-Legrange's, for prepar- 
 ing tannic acid, 45 
 buff leather, 363 
 chrome, Heinzerling's, 262, 263, 
 324 
 popularity of, 372 
 Knapp's, 324 
 Schultz's, 324 
 Coez's, for preparing tannic acid, 
 
 47 
 Crosse's, of tanning bv electri- 
 city, 258 
 Deyeux's, for preparing tannic 
 
 acid, 46 
 Dize's, for preparing tannic acid, 
 
 45 
 Drake's tanning, 8, 207 
 electrotype, 431 
 for softening dried hides, 
 
 Brain's, 111 
 Gaulard's, of tinning by electri- 
 city, 255, 256 
 Guest and Court's, 456 
 Hibberd's, of hemlock tanning, 
 
 252 
 Keasle}-'s, 8, 182 
 Knowlys' and Duesbury's, 8, 208 
 Kohlrausch's, for preparing tan- 
 nic acid, -48 
 lime, 115 
 
 supposed disadvantages of, 
 121 
 Merat-Guillot's, for preparing 
 
 tannic acid, 45 
 Meriten's, of tanning by electri- 
 city, 257 
 Nossiter's, 8, 198 
 of bating, Turnbull's, 141 
 bating, Warrington's, 141 
 chemical tanning, Vander- 
 
 straaten's, 266 
 depilation, Beck's, 136 
 
INDEX. 
 
 477 
 
 Process of depilation, Palmer's, 134 
 tanning, Drake's, 207 
 Fryer, Watt and Holmes's, 
 
 209 
 Knowlys and Duesbury's, 
 
 208 
 Mouren's, 209 
 Spilsbury's, 206 
 Pelouze's, for preparing tannic 
 
 acid, 43 
 Proust's, for preparing tannic 
 
 acid, 46 
 quick tanning, 211 
 
 Baron's process, 219 
 Bell's process, 219 
 Danish process, 221 
 Dietz's process, 217 
 Guiot's process, 221 
 Needham's process, 218 
 Nuessly's process, 218 
 Schering's, for preparing tannic 
 
 acid, 46 
 Serturner's, for preparing tannic 
 
 acid, 46 
 Spilsbury's, 8, 206 
 tanning, Aldrich's, 171 
 
 Ballatschano and Trenk's, 
 
 174 
 Bez and Sons', 192 
 Burbidge's, 203 
 Cox's, 198 
 De Bock's, 196 
 Desmond's, 202 
 for hard leathers, 181 
 for soft leathers, 181 
 Funcke's, 197 
 Hamer's, 197 
 Jennings', 174 
 Keasley's, 182 
 Kleman's, 204 
 Lomas', 176 
 Michel, Kollen and Hert- 
 
 zog's, 176 
 Newton's, 170 
 Nossiter's, 198 
 Old Irish, 268 
 Orgereau's, 173 
 Page's, 191 
 Snyder's, 196 
 unhairing, Prof. Lupkin's, 
 
 233 
 Ward's, of tanniDg by electricity, 
 254 
 Processes of chemical tanning, 
 Knapp's, 261 
 Ileinzerling's chrome, 262, 263 
 miscellaneous, 268 
 
 Procter on Lowenthal's method of 
 
 estimating tannin, 100 
 Properties of gallic acid, 60 
 
 of gelatine, 11 
 lime, 117 
 tannic acid, 49 
 Prosopis pallida, 84 
 Protea grandiflora, 86 
 Protosulphate of iron, 51 
 Proust's process for preparing tannic 
 
 acid, 46 
 Pressure, tanning by, 206 
 Prussian blue, 297 
 Prussiate of potash, 263 
 Pterocarpus erinaceus, 76 
 
 marsupium, 76, 85 
 Puce dyes, 300 
 Pudis sumach, 79 
 Pulp for paper-making from waste 
 
 tan, 455 
 Punica granatum, 85 
 Pure aniline colours, dyeing with, 304 
 
 or drench, 140, 316 
 
 tannic acid, 51 
 Purimbas, 85 
 Puring, 316, 332 
 Putrefactive fermentation, 128 
 Putrid fermentation, 442 
 Putting out chrome leather, 340 
 Pyenocama macrophylla, 84 
 Pyrogallic acid, 14, 50, 61 
 Pyroligneous acid, 65, 67 
 
 QUEBEACHO, 86 
 extract, 77 
 Quercitannic acid, 101 
 Quercitron, 86 
 Quercus coccifera, 70, 85 
 fflgilops, 81, 86 
 falcata, 70 
 glomerata, 70 
 ilex, 85 
 
 infectoria, 43, 74, 85 
 macrolepis, 81 
 pedunculata, 70, 85 
 pubescens, 85 
 robur, 70 
 rubra, 70 
 sessiliflora, 70, 85 
 stenophylla, 81 
 suber, 70, 84 
 tinctoria, 70, 86 
 Quick tanning, 211 
 
 Baron's process, 219 
 Bell's process, 219 
 Danish process, 221 
 Dietz's process, 217 
 
478 
 
 INDEX. 
 
 Quick tanning, Dr. Ure's views on, 
 
 213 
 Dussauce's observations on, 
 
 215 
 Guiot's process, 221 
 Needham's process, 218 
 Nuessly's process, 218 
 
 KAISING, 138, 292, 297 
 or swelling, 131 
 Raising with vitriol, 241 
 Ramspacker's method of estimating 
 
 tannin, 102 
 Rape oil, 205 
 Raw hides, abusive treatment of, 35 
 
 ]V1. Lange on the abusive treat- 
 ment of, 35 
 Reactions of tannic acid, 52 
 
 stocking, 400 
 Recipes for size, 384, 385 
 Red arsenic, 329 
 
 birch, 86 
 
 dressing, 295 
 
 dve, 299 
 
 Morocco leather, 299 
 Remarks, Morrit's, on white dressing, 
 
 295 
 Reptile skins, 431 
 Resin, 263, 379 
 Re-tanning, 376, 392 
 Rete mucosum, 23 
 Rbatany, 68, 86 
 
 root, 53, 80 
 Rheum rhaponticum, 49 
 Rhus coriaria, 78, 86 
 
 cotinus, 77 
 
 myrtifolia, 85 
 
 semialata, 74 
 Roan, 290 
 Roans, 435 
 Roller, American pendulum, 167 
 
 electrotyped copper, 332 
 
 hand, 165 
 Rolling machine, 166, 409 
 
 the leather, 165 
 Roman calcei mullei, 6 
 
 crepida, 6 
 
 perones, 6 
 
 shoes, 6 
 
 soleae, 6 
 
 strings, 447 
 Rosa canina, 49 
 
 gallica, 49 
 Rounding, or trimming, 236, 373 
 
 and sorting, 373 
 
 knife, 127 
 
 table, 126 
 
 Rounding the pelts, 126 
 
 Rubstone, 370 
 
 Russia leather, black, 281 
 
 leather, 2, 277 
 
 method of preparing, 279 
 
 or Yufts, 279 
 
 wormwood, 289 
 Rye meal, 294 
 
 QACCHARATE of lime, 141 
 
 £5 Saffron, 86 
 
 Sagre, 3 
 
 Sagri, 3 
 
 Sal ammoniac, 440 
 
 soda, 218 
 Salix alba, 86 
 
 cinerea, 86 
 Salt, iron, 261 
 
 solution, 191 
 Salted hides, 30 
 
 dry, 112 
 
 wet, 112 
 Saltpetre, 191 
 Salts, ammoniacal, 255 
 
 ferric, 14 
 Salvia officinalis, 49 
 Salzburg vitriol, 305 
 Sam, or samm, 155, 396 
 Sandstone, 369 
 Sanguisorba officinalis, 49 
 Sassafras, 86 
 
 bark, 54 
 Saul tree, 86 
 Saxon blue, 300 
 Scarf skin, 11, 23, 26 
 Scheele's method of preparing gallic 
 
 acid, 58 
 Schultz on the cost of tanning, 272 
 
 description of the turret drier 
 by, 159 
 Schultz's chrome leather process, 324 
 
 views on the treatment of hides, 
 112 
 Scilla maritima, 86 
 Scotch stone, 370 
 Scouring, 155 
 
 (gut dressing), 441 
 
 house, 368 
 
 machines, 155, 413 
 
 stone, 155 
 Scraping, 442 
 Scud, 316 
 Scudding, 125, 140, 284, 316, 333, 365, 
 
 366 
 Seal skin, 297 
 
 skins, 41 
 Seaside grape, 86 
 
INDEX. 
 
 479 
 
 Seasoning, 317, 343, 355, 394 
 Seasons ior box-calf, 355 
 
 for chrome leather, 342, 343, 
 346 
 Sebaceous glands, 26 
 Second boiling (glue), 452 
 Seguin's theory of the art of fanning, 
 15 
 Sir H. Davy on, 17 
 Dr. Ure on, 16 
 Dussnuce on, 16 
 Selection of hides, 31, 223 
 Sensitive plant, S3 
 Serpent and crocodile skins, 42 
 Seruirner's process for preparing tan- 
 nic acid, 46 
 Servic&tree, 55 
 Sesame, oil of, 289 
 Setting, 380 
 
 kip butt, machine, 380 
 Sesquichloride of iron, 52 
 Sesquioxide of iron, 264 
 Shagreen, 440 
 
 fish. 440 
 
 leather, 2, 38 
 
 parchment and vellum, 437 
 Shamois leather, 39 
 Shark skin, 440 
 Shaver or beamsman, 375 
 Shaving, 317, 336, 351 
 
 by machinerv, 375, 410 
 
 knife, 371, 410 
 
 operation, 375 
 She oak, 86 
 Sheep intestines, cords from, 445 
 
 leather, white, 318 
 
 skins, 39 
 
 classification of, 435 
 green, 242 
 splitting, 320, 392 
 tawing, 318 
 Shoe.', high, black grain, 396 
 
 Eoman, 6 
 Shop, the currying, 369 
 Shorea robusta, 86 
 Sicilian sumach, 78 
 Silicon, sulphate of, 266 
 Single pit method, 118 
 Sir John Lubbock on the origin of 
 
 warbles, 32 
 Sirnabelli, 86 
 Size, recipe for, 384, 385 
 
 preparation of, 384, 453 
 
 for waxed leather, 385 
 Sizes, bottom, 383, 384 
 Skeleton drum. 235 
 
 reel, 235 
 
 Skin, 23, 26 
 
 and hide cuttings, 456 
 
 bottles, 5 
 
 buck, dressing, 366 
 
 camel, 440 
 
 composition of, 27 
 
 deer, 41 
 
 fish, or fish shagreen, 440 
 
 goldbeaters', 444 
 
 hog, 41 
 
 horse, 440 
 
 human, 24 
 
 illustration of the, 26 
 
 Mr. Ashe's description of the, 
 
 24 
 seal, 298 
 shark, 440 
 
 structure of the, 23, 36 
 wild ass, 440 
 Skins 28 
 
 alligator, 42, 431 
 
 &c, electrotyped, 432 
 and hides, 28 
 
 condition of, 38 
 depilation or unhairing 
 of, 115 
 asses', 439 
 boa-constrictor, 432 
 calf, for memel, 395 
 tawing, 314, 435 
 calves', 38 
 
 chamois, colouring, 362 
 crocodile, 432 
 
 elk, Indian method of prepar- 
 ing, 268 
 for drumheads, 439 
 goat, 40, 327, 328, 419 
 hog and pig, 41 
 kid, 40 
 
 treatment of, 307 
 lamb, Cape, 435 
 lambs', 435 
 Mogadore, 40 
 pickled (Australian and New 
 
 Zealand), 327 
 porpoise, 42 
 reptile, 431 
 seal, 41 
 
 serpent and crocodile, 42 
 sheep, 39 
 
 Cape, 435 
 
 Cots wold, 435 
 
 classification of, 435 
 
 Leicester, 435 
 
 Lincoln, 435 
 
 Southdown, 435 
 smoking, 279 
 
480 
 
 INDEX-. 
 
 Skins, split, 440 
 
 splitting, 320, 38G, 411 
 
 tawing, 306 
 
 treatment of, 435 
 
 Welsh, 435 
 Skiver, 39, 288, 325 
 
 leather, 322, 35G 
 Sleaker, 377, 381, 393 
 
 stone, 387 
 
 whitening, 381, 390 
 Slimed, 312 
 Small steel, 370 
 Smoke-cured leather, 5 
 
 house, 128 
 Smoking skins, 279 
 Snyder's tanning process, 196 
 Soaking and liming, 315 
 
 the leather, 374 
 Soap, brown, 391 
 
 iron, 261 
 
 soft, 352 
 Sod oil, 360, 379 
 Soda ash, 234 
 
 caustic, 131 
 
 chromate of, 262 
 
 hyposulphite of, 324 
 
 nitrate of, 262 
 
 sal, 218 
 
 thiosulphite of, 324 
 Sodium, sulphide of, 133 
 
 tungstate of, 264 
 Soft leather, tanning process for, 
 
 181 
 Softening dried hides, 110 
 Sogah, 86 
 Solea?, Roman, 6 
 Sole butts, 456 
 
 leather tanning, machinery used 
 in, 400-430 
 Soluble chromates, 263 
 Sorting and rounding, 373 
 Sources of tannin, 68 
 Southdown sheepskins, 435 
 Spanish chestnut, 21 
 
 white, 180 
 Spent tan, 455 
 
 Spilsbury's tanning process, 206 
 Split co w -hides, currying, 396 
 for brown bags, 396 
 
 flesh, 289 
 
 sheepskins, 440 
 Splitting, 39, 387, 388_ 
 
 machine, 320, 375 
 
 sheep-kins, 320 
 Spondias lutea, 85 
 Squill, 53 
 Squills, 86 
 
 Stake, 320 
 
 Staking, 310, 317, 320, 341 
 
 Starching, 382 
 
 Statice, 53, 86 
 
 coriaria, 85, 86 
 Steam sweat, 229 
 Stearic acid, 312 
 Stearine, 263, 312, 379 
 Steep, bran, 318 
 Still-born calves, 437 
 Stocking, 359, 366 
 Stocks, fulling, 110 
 Stockstone, 377 
 Stone pine, 86 
 
 sleaker, 387 
 Stoning, 382, 387 
 Storing the lime, 118 
 Straight-grain roller, 396 
 Strasburg vellum, 439 
 Striker, Priestman's. 407 
 Striking, 163, 308 
 
 a butt, 164 
 
 machine, 164 
 
 pin, 163 
 Striking out chrome leather, 336, 340, 
 
 351 
 Stringed instruments, 446 
 Strings, Roman, 447 
 Structure of the skin, 23, 26 
 Stryphnodendron barbatemas, 86 
 Stuffing machine mixture, 379, 
 
 380 
 Subaujuna, 86 
 Sugar, gelatine, 12 
 
 grape, 459 
 Sulfamine dyes, 345 
 Sulphate of alumina, 170 
 copper, 264 
 iron, basic, 261 
 manganese, 264 
 protoxide of iron, 264 
 silicon, 266 
 zinc, 221, 264 _ 
 Sulphide of sodium, depilationby, 133, 
 
 330 
 Sulphur, 234 
 
 chloride of, 265 
 Sulphuration, 443 
 Sulphuret of lime, 132 
 Sulphuretted hydrogen, 46, 329 
 Sulphuric acid, 95, 141, 174, 301, 337, 
 
 388 
 Sumach, 86 
 
 and gambier liquor, 377 
 
 bath, 388 
 
 Alcamo, 78 
 
 Donzeri, 79 
 
INDEX. 
 
 4S1 
 
 Sumach, infusion, 97 
 
 Molina, 79 
 
 Porto, 79 
 
 Portuguese, 79 
 
 Priego, 78 
 
 Silician, 78 
 
 tanning, 285 
 
 Valladolid, 79 
 Supposed disadvantages of the lime 
 
 process, 121 
 Suspenders, 153 
 Suspension, tanning by, 153 
 Sweat pits,' 229 
 
 treatment of hides in, 230 
 
 steam, 229 
 Sweating, 128 
 
 cjjld, 129, 229 
 
 depilation by, 128 
 
 of hides, cold, 229 
 
 treatment of hides, after, 231 
 Sweet liquors, 251 
 
 oil of almonds, 311 
 Swelling, or raising, 138 
 Swiss goat-skins, 40 
 Sycamore bark, 54 
 
 System, metrical, weights and mea- 
 sures of the, 461 
 
 modern, of tanning, 145 
 
 TABLE of the percentage of tannin 
 in vegetable substances, 53 
 Tallow, buck, 396 
 deer, 396 
 mutton, 440 
 Tallowing, 395 
 Tamaria gallica, 87 
 Tamarisk galls, 86 
 Tamarix indica, 86 
 Tampico skins, 40 
 Tan pits, 152 
 shrub, 55 
 spent, 454 
 Tan-burning boiler, 454 
 Tangede, 86 
 Tannage, French, 382 
 
 hemlock, 389 
 Tannate of iron, 51 
 
 lime, 16, 71 
 magnesia, 71 
 potash, 71 
 tin, 46 
 Tanned butts, drying, 156 
 Tanners' machinery, 399-430 
 
 waste, utilisation of, 455 
 Tannic acid, 11, 43, 50, 301 
 
 preparation of, Badvil and 
 Lienders' process, 47 
 
 Tannic acid, preparation of, Berzelius' 
 process, 44 
 preparation of, Bouillon-Le- 
 
 grange's process, 45 
 preparation of, Coez's pro- 
 cess, 47 
 preparation of, Deyeux's 
 
 process, 46 
 preparation of, Dize's pro- 
 cess, 45 
 preparation of,Kohlrausch's 
 
 process, 48 
 preparation of, Merat-Guil- 
 
 lot's process, 45 
 preparation of, Pelouze's 
 
 process, 43 
 preparation of, Proust's pro- 
 cess, 46 
 preparation of, Schering's 
 
 process, 46 
 preparation of, Serturner's 
 
 process, 46 
 properties of, 49 
 pure, 51 
 reactions of, 52 
 Tannin, 11, 18, 43 
 
 Bell Stephens' method of esti- 
 mating, 92 
 Davy's method of estimating, 92 
 Hammer's method of estimating, 
 
 93 
 Hewitt on Lowenthal's method 
 
 of estimating, 97 
 Lowenthal's method of esti- 
 mating, 94 
 Procter on Lowenthal's method 
 
 of estimating, 100 
 Ramspacker's method of esti- 
 mating, 102 
 table of percentage of, in vege- 
 table substances, 53 
 Tanning, 226 
 
 American, 228 
 
 as distinguished from tawing, 
 
 306 
 bark, 143 
 butts, 143 
 
 for sole leather, 143 
 by electricity, 254 
 
 Crosse's process, 258 
 Gaulard's process, 255, 256 
 Meriten's process, 257 
 Ward's process, 254 
 by pressure, 206 
 
 Drake's process, 207 
 Fryer, Watt, and Holmes's 
 process, 209 
 
 2i 
 
4S2 
 
 INDEX. 
 
 Tanning, by pressure, Knowlys and 
 Duesbury's process, 208 
 
 Mouren's process, 209 
 
 Spilsbury's process, 206 
 by suspension, 153 
 chemical, Knapp's process, 261 
 Vanderstraaten's process, 266 
 chrome, 334, 349 
 composition for, 253 
 cost of American, 272 
 extracts, 74 
 
 first English patents for, 169 
 glycerine in, 269 
 Heinzerling's chrome process, 
 
 262, 324 
 hemlock, 245 
 
 Hibberd's process, 252 
 
 of New Lebanon, N.J., 249 
 materials, 68 
 modern system of, 145 
 nets, sails, and cordage, 269 
 old Irish process of, 268 
 
 methods of, 144 
 Pratt's system of, 245 
 principles of, 7 
 process, Aldrich's, 171 
 
 Ballatschano and Trenk's, 
 174 
 
 Bez and Sons', 192 
 
 Burbidge's, 203 
 
 Cox's, 198 
 
 De Bock's, 196 
 
 Dennis's taolin, 349 
 
 Desmond's, 202 
 
 Funcke's, 197 
 
 Guiot's, 221 
 
 Hamer's, 197 
 
 hard leather, 181 
 
 Jennings', 174 
 
 Keasley's, 182 
 
 Kleman's, 204 
 
 Lomas', 176 
 
 Michel, Kollen, and Hert- 
 zog's, 176 
 
 Newton's, 170 
 
 Nos>iter's, 198 
 
 Orgereau's, 173 
 
 Page's, 191 
 
 Prenzlau's corin. 350 
 
 Procter's, 350 
 
 Snyder's, 196 
 
 soft leather, 181, 374 
 processes, 169 
 quick, 211 
 
 Baron's process, 219 
 
 Bell's process, 219 
 
 Danish process, 221 
 
 Tanning, quick, Dietz's process, 
 217 
 Dr. lire's views on, 213 
 Dussauce's observations on, 
 
 215 
 Guiot's process, 221 
 Needham's process, 218 
 Nuessly's process, 218 
 
 Schultz on the cost of, 272 
 
 Seguin's theory of, 15 
 
 sole leather, machinery used in, 
 400 
 
 sumach, 285 
 
 theory of, 1 1 
 Tanno-gelatine, 51, 91 
 Tannometer, 102 
 Tanolin, 349 
 Taps, or leaches, 146 
 Tarsekeha, 86 
 Tartar, 299 
 Tartaric acid, 65, 301 
 Tasmanian laurel, 86 
 Tawed hides, 38 
 
 leather, 317 
 Tawing, 306, 314, 435 
 
 as distinguished from tanning, 
 306 
 
 calf-skins, 314 
 
 operations, 306 
 
 paste, 313 
 
 Schultze's process, 324 
 
 sheepskins, 318 
 Tea, 17 
 
 Tennis bats, &c, cords for, 446 
 Terce, 86 
 Terminalia bellerica, 81 
 
 chelula, 81, 85 
 
 citrina, 85 
 
 formentosa, 87 
 Terra japonica, 53, 86 
 Thiosulphite of soda, 324 
 Third boiling (glue), 452 
 Thyme oil, 3 
 Tilia Europaea, 49 
 Tin, chloride of, 46 
 
 muriate of, 191 
 
 tannate of, 46 
 Titration, 94 
 To determine when leather is tanned! 
 
 throughout, 167 
 Tongs, 283 
 Top-sizing, 384 
 Tooth-board, 396 
 Tormentil, 54, 86 
 Tormentilla erecta, 49 
 Tormentilia potentilla, 86 
 Towhai, 86 
 
INDEX. 
 
 483 
 
 Trade in American leather, 372 
 
 Tramping drum, 262 
 
 Treatment of glue pieces, 449 
 
 green or fresh hides, 108 
 hides after sweating, 231 
 hides in sweat pits, 230 
 intestines, 447 
 kid skins, 307 
 skins, 435 
 
 preliminary, 108 
 with alum and salt, 308 
 
 Trees, barking of, 71 
 
 Trichinae, 32 
 
 Trichinosis, 32 
 
 Trimming, or rounding, 236, 342, 373 
 
 True skin, 11, 26 
 
 Tuckjng, 362 
 
 Tuga vesca, 86 
 
 Tumbler, 308, 415 
 air-heated, 378 
 
 Tungstate of potassium, 264 
 of sodium, 264 
 
 Turnbull's process of bating, 141 
 
 Turning over (gut dressing), 442 
 
 Turpentine, essence of, 181 
 
 Turret drier, American, 159 
 working of, 160 
 
 Turwar, 86 
 
 Two-bath method for calf-sHns, 348 
 for goat-skins, 327 
 
 UNCAFJA GAMBIR, 74, 77, 86 
 Unhairing, 124, 315 
 Unhairing and fleshing, 315, 329 
 
 by machinery, 315, 402, 429 
 by Prof. Lupkin's process, 233 
 knife, 124 
 
 or depilation of skins and hides, 
 115 
 Union lime sole leather, 272 
 
 splitting machine, 322, 412 
 Uppers, calf kid for, 314 
 Ure on Seguin's theory, 16 
 Utilisation of tanners' waste, 455 
 Uva ursi, 49 
 
 YALLADOLID sumach, 79 
 Valonia, 54, 81, 86, 405 
 Valonia oak, 81 
 Vanderstraaten's process of chemical 
 
 tanning, '266 
 Various leathers, currying, 395 
 Varnish, 297 
 
 amber, 298 
 copal, 298 
 
 Vegetable black, 297 
 
 extractive, 45, 215 
 
 tannin, 266 
 
 wax, 265 
 Vellum and parchment, preparation 
 of, 437 
 
 parchment, and shagreen, 437 
 
 Strasburg, 439 
 Verdigris crystallised, 439 
 Vinegar, 292 
 
 wood, 218' 
 Violet dve, 300' 
 
 methyl, 304 
 Vitriol, copper, 305 
 
 green, 261, 305 
 
 oil of, 241 
 
 raised leather, 241 
 
 raising with, 241 
 
 Salzburg, 305 
 
 zinc, 305 
 Vitriols, mixed, 305 
 
 WAGEN boom, 86 
 Wallachia leather, 291 
 Walrus hides, 38 
 Warble marks, 31 
 
 Warbles, observation on the origin 
 of, 32 
 Sir John Lubbock on the origin 
 of, 32 
 Ward's process of tanning by elec- 
 tricity, 254 
 Warrington's process of bating, 141 
 Washing and cleansing, 224, 334, 300, 
 365 
 
 (gut dressing), 442 
 Waste, glue, 453 
 hair, 457 
 lime, 132, 458 
 tanners', utilisation of, 455 
 Water plantain, 86 
 
 stove, 136 
 Wax leather, 372, 374, 396 
 extinction of, 372 
 vegetable, 205 
 Waxed leather, 383 
 kip butts, 373 
 Waxing, 383 
 Weights of hides, 30 
 
 and measures of the metrical 
 system, 461 
 Weinmannia racemosa, 86 
 Welsh sheepskins, 435 
 
 stone, 370 
 Wet salted hides, 112 
 Whip cords, 446 
 
4 8 4 
 
 INDEX. 
 
 White dressing, 130 
 
 Mornt's remarks on, 295 
 
 galls, 73 
 
 leather, manufacture of, 30G 
 
 mangrove, 85 
 
 sheep leather, 318 
 Whitening, 381, 382 
 
 graining in after, 382 
 
 sleaker, 381, 390 
 Wild ass skin, 440 
 
 orach, 3 
 Willow, 86 
 
 hark, 54 
 
 Leicester, 21 
 Wilson's striker, 407 
 Winter's bar' - , 55 
 Woo-pei-tzee, 74 
 Wood ashes, 219 
 Woolstapler, 287, 436 
 
 Working in rounds, 118 
 
 of the turret drier, 159 
 on the beam, 124 
 
 Works, methods in up-to-date leather, 
 372 
 
 Wormwood, Russia, 289 
 
 YEAST, 296 
 - 1 - Yellow dye, 300 
 Yellow methanil, 302 
 
 naphthol, 304 
 
 naphtholine, 302 
 Young oak-bark, 53 
 Yufts Russia leather, 279 
 
 ZINC, borate of, 264 
 chloride of, 264 
 sulphate of, 264 
 vitriol, 350 
 
 THE END 
 
 FttlNTKD tit WILLIAM CLOWES AND SONS, LIMITED, LONDON AND BECCLES. 
 
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 t5F".ihis Work is issued in continuation of the series of handbooks 
 written 6y the Author, viz: "The Works' Manager's Handbook" and 
 "The Practical Engineer's Handbook," which are so highly appreciated 
 by engineers for the practical nature of their information, and is consequently 
 written in the same style as those works. 
 
 Contents: — Heat, Radiation, and Conduction, Non-conductin g 
 Materials, and Coverings for Steam Boilers. — Composition, Calorific 
 Power, and Evaporative Power of Fuels. — Combustion, Firing Steam 
 Boilers, Products of Combustion, &c. — Chimneys for Steam Boilers. — 
 
4 CROSBY LOCKWOOD &■ SON'S CATALOGUE. 
 
 Steam Blast. 1 — FORCE Draught."— FEED Water. — Effect of Heat on 
 Water. — Expansion of Water by Heat. — Weight of Water at Differ- 
 ent Temperatures. — Convection. — Circulation. — Evaporation. — 
 Properties of Saturated Steam. — Evaporative Power of Boilers. — 
 Priming, &c. — Water-Heating Surfaces of Steam Boilers. — Trans- 
 mission of Heat. — Smoke Tubes. — Evaporative Powers and Effi- 
 ciency of Boilers. — Water Capacity and Steam Capacity of Boilers. — 
 Fire-Grates, Fire-Bridges, and Fire-Bars. — Power of Boilers. — 
 Cylindrical Shells and Furnace-Tubes of Boilers, &c. 
 
 Tests of Materials. — Strength and Weight of Boiler-Plates. — 
 Effect of Temperature on Metals. — Rivet Holes. — Rivets. — Rivet 
 Joints of Steam Boilers. — Caulking. — Ends of Cylindrical Shells. — 
 Stays for Boilers, &c. — Steam Generators. — Description and Pro- 
 portions of Cornish, Lancashire, and Other Types of Stationary 
 Boilers. — Boiler Setting. — Multitubular Boilers. — Locomotive 
 Boilers. — Portable Boilers. — Marine Boilers. — Vertical Boilers. — 
 Water-tube Boilers. — Superheaters. — Cost of Steam Production. — 
 Furnaces for Refuse Fuels. — Destructors, &c. 
 
 Safety- Valves. — Steam Pipes. — Stop- Valves, and Other Mountings 
 for Boilers. — Feed Pumps. — Steam Pumps. — Feed- Water Consumption. 
 — Injectors. — Incrustation and Corrosion. — Feed- Water Heaters. — 
 Evaporators. — Testing Boilers. — Evaporative Performances of 
 Steam Boilers. Steam-Boiler Explosions, &c. 
 
 PLATING AND BOILER MAKING. 
 
 A Practical Handbook for Workshop Operations. By Joseph G. Hor- 
 ner, A.M.I.M.E. 380 pp. with 338 Illustrations. 12mo cloth. .$3.00 
 Contents: — The Trade. — Tools. — Materials. — Testing Materials. — 
 Limiting Dimensions and Weights of Materials. — Cutting and 
 Straightening Plates, &c. — Bending Plates. — Bending Angles, &c. — 
 Welding. — Flanging. — Punching. — Riveting. — Types of Riveted 
 Joints. — Estimation of Lengths of Material. — The Marking Out of 
 Work. — The Estimation of Weights, &c. — Machines. 
 
 A TREATISE ON STEAM BOILERS. 
 
 Their Strength, Construction, and Economical Working. By R. Wil- 
 son, C.E. Fifth Edition. 12mo, cloth $2.50 
 
 "The best treatise that has ever been published on steam boilers." — En- 
 gineer. 
 
 BOILER AND FACTORY CHIMNEYS. 
 
 Their Draught-Power and Stability. With a chapter on Lightning Con- 
 ductors. By Robert Wilson, A.I.C.E., Author of "A Treatise on 
 Steam Boilers," etc. 12mo, cloth $1.50 
 
 BOILERMAKER'S ASSISTANT 
 
 In Drawing, Templating, and Calculating Boiler Work, etc. By J. 
 Courtney, Practical Boilermaker. Edited by D. K. Clark, C.E. 
 Seventh Edition. 12mo, cloth .80 
 
 BOILERMAKER'S READY RECKONER. 
 
 With Examples of Practical Geometry and Templating for the Use of 
 Platers, Smiths, and Riveters. By John Courtney. Edited by D. 
 K. Clark, M.Inst. C.E. Crown 8vo, cloth $1.60 
 
 BOILERMAKER'S READY RECKONER & ASSISTANT. 
 
 With Examples of Practical Geometry and Templating for the Use of 
 Platers, Smiths, and Riveters. By John Courtney. Edited by D.K. 
 Clark, M.Inst.C.E. Fifth Edition, 480 pp., with 140 Illustrations. 
 Fcap. 8vo, half-bound $3.00 
 
 *** This Work consists of the two previous-mentioned volumes, "Boiler- 
 maker's Assistant" and "Boilermaker's Ready Reckoner," bound 
 together in One Volume. 
 
MECHANICAL ENGINEERING, 6-c. 5 
 
 STEAM BOILERS. 
 
 Their Construction and Management. By R. Armstrong, C.E. Illus- 
 trated. Crown 8vo, cloth yQ 
 
 THE PRACTICAL ENGINEER'S HANDBOOK. 
 
 Comprising a Treatise on Modern Engines and Boilers; Marine, Loco- 
 motive, and Stationary. And containing a large collection of Rules and 
 Practical Data relating to Recent Practice in Designing and Construct- 
 ing all kinds of Engines, Boilers, and other Engineering Work. The 
 whole constituting a comprehensive Key to the Board of Trade and 
 otcer Examinations for Certificates of Competency in Modern Mechan- 
 ical Engineering. By Walter S. Hutton, Civil and Mechanical En- 
 gineer, Author of "The Works' Manager's Handbook for Engineers," 
 &c. With upwards of 420 Illustrations. Sixth edition, Revised and 
 
 Enlarged. Medium 8vo, nearly 560 pp., strongly oound $7.00 
 
 C3F™ This Work is designed as a companion to the Author's "Works' 
 Manager's Handbook." It possesses many new and original features, and 
 contains, like its predecessor, a quantity of matter not originally intended for 
 publication, but collected by the Author for his own use in the construction of a 
 great variety of Modern Engineering Work. 
 
 The information is given in a condensed and concise form, and is illus- 
 trated by upwards of 420 Engravings; and comprises a quantity of tabulated 
 matter of great value to all engaged in designing, constructing, or estimating for 
 Engines, Boilers, and other Engineering Work. 
 
 TEXT-BOOK ON THE STEAM ENGINE. 
 
 With a Supplement on Gas Engines and Part II. on Heat Engines 
 By T. M. Goodeve, M.A., Barrister-at-Law, Professor of Mechanics at 
 the Royal College of Science, London; Author of "The Principles of 
 Mechanics," "The Elements of Mechanism," &c. Fourteenth Edition. 
 
 Crown 8vo, cloth $2.0i) 
 
 "Professor Goodeve has given us a treatise on the steam engine which will 
 
 bear comparison with anything written by Huxley or Maxwell, and we can 
 
 award it no higher praise." — Engineer. 
 
 A HANDBOOK ON THE STEAM ENGINE. 
 
 With especial Reference to Small and Medium-sized Engines. For the 
 Use of Engine Makers, Mechanical Draughtsmen, Engineering Students, 
 and users of Steam Power. By Herman Haeder, C.E. Translated 
 from the German, with additions and alterations, by H. H. P. Powles, 
 A.M.I.C.E., M.I.M.E. Third Edition, Revised. With nearly 1,100 
 
 Illustrations. 12mo, cloth $3.00 
 
 Summary of Contents : — Introduction. — Types of Steam Engines. — 
 Details of Steam Engines. — Governors. — Valve Gears. — Condensers, 
 
 alr-pumps, and feed-pumps. examples of engines of continental 
 
 Make, from Actual Practice. — Particulars of Engines by English 
 Makers. — Compound Engines. — Indicator and Indicator Diagrams. — 
 Calculations for Power and Steam Consumption. — Effect of Inertia 
 on Reciprocating Parts of Engines. — Friction Brake Dynamometer — 
 Sundry Details. — Boilers. — Index. 
 
 " There can be no question as to its value. We cordially commend it 
 to all concerned in the design and construction of the steam engine." — 
 Mechanical World. 
 
 THE PORTABLE ENGINE. 
 
 A Practical Manual on its Construction and Management, for the use 
 of Owners and Users of Steam Engines generally. By William Dyson 
 
 Wansbrough. 12mo, cloth $1.50 
 
 "This is a work of value to those who use steam machinery. . . . Should 
 
 be read by every one who has a steam engine, on a farm or elsewhere." — 
 
 Mark Lane Express. 
 
6 CROSBY LOCKWOOD &• SON'S CATALOGUE. 
 THE STEAM ENGINE. 
 
 A Treatise on the Mathematical Theory of, with Rules and Examples 
 tor Practical Men. By T. Baker, (J.E. 12mo, cloth 60 
 
 "Teems with scientific information with reference to the steam-engine." — 
 Design and Work. 
 
 THE STEAM ENGINE. 
 
 For the use of Beginners. By Dr. Lahdner. 12mo, cloth. . . .60 
 
 LOCOMOTIVE ENGINE DRIVING. 
 
 A Practical Manual for Engineers in Charge of Locomotive Engines. 
 By Michael Reynolds, M.S.E. Twelfth Edition. 12mo, cloth 
 
 boards $2.00 
 
 "We can confidently recommend the book, not only to the practical driver, 
 
 but to every one who takes an interest in the performance of locomotive 
 
 engines." — The Engineer. 
 
 THE LOCOMOTIVE ENGINE. 
 
 The Autobiography of an Old Locomotive Engine. By Robert 
 Weatherburn, M.I.M.E. With Illustrations and Per traits of George 
 and Robert Stephenson. 12mo, cloth $1.00 
 
 THE LOCOMOTIVE ENGINE AND ITS DEVELOPMENT. 
 
 A Popular Treatise on the Gradual Improvements made in Railway 
 Engines between 1803 and 1903. By Clement E. Stretton, C.E. 
 
 Sixth Edition, Revised and Enlarged. 12mo, cloth $2.00 
 
 "Students of railway history and all who are interested in the evolution 
 
 of the modern locomotive will find much to attract and entertain in this 
 
 volume." — The Times. 
 
 THE MODEL LOCOMOTIVE ENGINEER, 
 
 Fireman, and Engine-Boy. Comprising a Historical Notice of the 
 Pioneer Locomotive Engines and their Inventors. By Michael Reyn- 
 olds. Second Edition, with Revised Appendix. 12mo, cloth. $2.00 
 "We should be glad to see this book in the possession of every one in the 
 
 kingdom who has ever laid, or is to lay, hands on a locomotive engine." — 
 
 Iron. 
 
 LOCOMOTIVE ENGINES, 
 
 A Rudimentary Treatise on. By G. D. Dempsey, C.E. With large 
 Additions treating of the Modern Locomotive, by D. K. Clark, 
 
 M.Inst.C.E. With Illustrations. 12mo, cloth $.120 
 
 "A model of what an elementary technical book should be." — Academy. 
 
 CONTINUOUS RAILWAY BRAKES. 
 
 A Practical Treatise on the several Systems in Use in the United King- 
 dom; their Construction and Performance. By M. Reynolds. 8vo, 
 cloth $3.50 
 
 ENGINE-DRIVING LIFE. 
 
 Stirring Adventures and Incidents in the Lives of Locomotive Engine- 
 Drivers. By Michael Reynolds. Third Edition. 12mo, cloth. .60 
 
 STATIONARY ENGINE DRIVING. 
 
 A Practical Manual for Engineers in Charge of Stationary Engines. By 
 Michael Reynolds, M.S.E. Seventh Edition. 12mo, cloth boards. 
 
 $2.00 
 THE CARE AND MANAGEMENT OF STATIONARY 
 
 ENGINES. 
 
 A Practical Handbook for Men-in-charge. By C. Hurst. 12mo. .50 
 
MECHANICAL ENGINEERING, &c. 7 
 
 THE ENGINEMAN'S POCKET COMPANION 
 
 and Practical Educator for Enginemen, Boiler Attendants, and Me- 
 chanics. By Michael Reynolds. With 45 Illustrations and numer- 
 ous Diagrams. Fifth Edition. Royal 18mo, strongly bound for 
 
 Pocket wear $1.50 
 
 "A most meritorious work, giving in a succinct and practical form all the 
 
 information an engine-minder, desirous of mastering the scientific principles 
 
 of his daily calling, would require." — The Miller. 
 
 THE SAFE USE OF STEAM. 
 
 Containing Rules for Unprofessional Steam Users. By an Engineer. 
 
 Eighth Edition. Sewed .25 
 
 "If steam-users would but learn this little book by heart, boiler explo- 
 sions would become sensations by their rarity." — English Mechanic. 
 
 STEAM AND MACHINERY MANAGEMENT. 
 
 A Guide to the Arrangement and Economical Management of Machin- 
 ery, with Hints on Construction and Selection. By M. Powis Bale, 
 M.Inst.M.E. 12mo, cloth $1.00 
 
 GAS AND OIL ENGINE MANAGEMENT. 
 
 A Practical Guide for Users and Attendants, being Notes on Selection, 
 Construction, and Management. By M. Powis Bale, M.Inst.C.E., 
 M.I.Mech.E. Author of "Woodworking Machinery," &c. 12mo, 
 cloth $1.50 
 
 ON GAS ENGINES. 
 
 With Appendix describing a Recent Engine with Tube Igniter. By 
 T. M. Goodeve, M.A. 12mo, cloth $1.00 
 
 THE ENGINEER'S YEAR=BOOK FOR 1906. 
 
 Comprising Formula, Rules, Tables, Data, and Memoranda in Civil, 
 Mechanical, Electrical, Marine, and Mine Engineering. By H. R. 
 Kempe, M.Inst.C.E., Principal Staff Engineer, Engineer-in-Chief's 
 Office, General Post Office, London; Author of "A Handbook of Elec- 
 trical Testing," "The Electrical Engineer's Pocket-Book," &c. With 
 1,000 Illustrations, specially Engraved for the Work. 12mo, 950 pp., 
 leather $3.00 
 
 THE MECHANICAL ENGINEER'S POCKET=BOOK. 
 
 Comprising Tables, Formulae, Rules, and Data: a Handy Book of Ref- 
 erence for Daily Use in Engineering Practice. By D. Kinnear Clark, 
 M.Inst.C.E., Fifth Edition, thoroughly Revised and Enlarged. By H. H. 
 P. Powles, A.M.Inst.C.E., M.I.M.E. Small 8vo, 700 pp., leather. $3.00 
 Summary of Contents: — Mathematical Tables. — Measurement of 
 Surfaces and Solids. — English Weights and Measures. — French 
 Metric Weights and Measures. — Foreign Weights and Measures. — 
 Moneys. — Specific Gravity, Weight, and Volume. — Manufactured 
 Metals. — Steel Pipes. — Bolts and Nuts. — Sundry Articles in Wrought 
 and Cast Iron, Copper, Brass, Lead, Tin, Zinc. — Strength of Mater- 
 ials. — Strength of Timber. — Strength of Cast Iron. — Strength of 
 Wrought Iron. — Strength of Steel. — Tensile Strength of Copper, 
 Lead, &c. — Resistance of Stones and other Building Materials. — 
 Riveted Joints in Boiler Plates. — Boiler Shells. — Wire Ropes and 
 Hemp Ropes — Chains and Chain Cables. — Framing. — Hardness of 
 Metals, Alloys, and Stones. — Labour of Animals. — Mechanical Prin- 
 ciples. — Gravity and Fall of Bodies. — Accelerating and Retarding 
 Forces. — Mill Gearing, Shafting, &c. — Transmission of Motive Power. 
 — Heat. — Combustion. — Fuels. — Warming, Ventilation, Cooking 
 Stoves. — Steam. — Steam Engines and Boilers. — Railways. — Tram- 
 ways. — Steam Ships. — Pumping Steam Engines and Pumps. — Coal Gas, 
 Gas Engines, &c. — Air in Motion. — Compressed Air. — Hot- Air Engines. 
 — Water Power. — Speed of Cutting Tools. — Colours. — Electrical 
 Engineering. 
 
8 CROSBY LOCKWOOD &* SON'S CATALOGUE. 
 
 PRACTICAL MECHANICS' WORKSHOP COMPANION. 
 
 Comprising a great Variety of the most useful Rules and Formulae in 
 Mechanical Science, with numerous Tables of Practical Data and Cal- 
 culated Results for Facilitating Mechanical Operations. By William 
 Templeton, Author of "The Engineer's Practical Assistant," &c, &c. 
 Eighteenth Edition, Revised, Modernised, and considerably Enlarged, 
 by W. S. Hutton, C.E., Author of "The Works' Manager's Hand- 
 book," &c. Feap. 8vo, nearly 500 pp., with 8 Plates and upwards of 
 250 Diagrams, leather $2.50 
 
 ENGINEER'S AND MILLWRIGHT'S ASSISTANT. 
 
 A Collection of Useful Tables, Rules, and Data. By William Temple- 
 ton. Eighth Edition, with Additions. 18mo, cloth $1.00 
 
 TABLES AND MEMORANDA FOR ENGINEERS, 
 MECHANICS, ARCHITECTS, BUILDERS, &c. 
 
 Selected and Arranged by Francis Smith. Seventh Edition, Revised, 
 including Electrical Tables, Formulae, and Memoranda. Waist- 
 coat-pocket size, limp leather > gQ 
 
 THE MECHANICAL ENGINEER'S COMPANION. 
 
 Of Areas, Circumferences, Decimal Equivalents, in inches and feet, mil- 
 limetres, squares, cubes, roots, &c. ; Strength of Bolts, Weight of Iron, 
 &c. ; Weights, Measures, and other Data. Also Practical Rules for 
 Engine Proportions. By R. Edwards, M.Inst.C.E. Fcap. 8vo, cloth. 
 
 $1 00 
 MECHANICAL ENGINEERING TERMS. 
 
 (Lockwood's Dictionary of). Embracing those current in the Drawing 
 Office, Pattern Shop, Foundry, Fitting, Turning, Smiths', and Boiler 
 Shops, &c. Comprising upwards of 6,000 Definitions. Edited by J. 
 G. Horner, A.M.I.M.E. Third Edition, Revised, with Additions. 
 12mo, cloth $3.00 
 
 "Just the sort of handy dictionary required by the various trades engaged 
 in mechanical engineering. The practical engineering pupil will find the 
 book of great value in his studies, and every foreman engineer and mechanic 
 should have a copy." 
 
 POCKET GLOSSARY OF TECHNICAL TERMS. 
 
 English-French, French-English; with Tables suitable for the Archi- 
 tectural, Engineering, Manufacturing, and Nautical Professions. By 
 John James Fletcher. Fourth Edition, 200 pp. Waistcoat-pocket 
 size, limp leather m QQ 
 
 IRON AND STEEL. 
 
 A Work for the Forge Foundry, Factory, and Office. Containing ready, 
 useful, and trustworthy Information for Ironmasters and their Stock- 
 takers; Managers of Bar, Rail, Plate, and Sheet Rolling Mills; Iron and 
 Metal Founders; Iron, Ship, and Bridge Builders; Mechanical, Mining, 
 and Consulting Engineers; Architects, Contractors, Builders, &c. By 
 Charles Hoare, Author of "The Slide Rule," &c. Ninth Edition. 
 32mo, leather $2.50 
 
 WORKMAN'S MANUAL OF ENGINEERING DRAWING. 
 
 By John Maxton, Instructor in Engineering Drawing, Royal Naval 
 College, Greenwich. Eighth Edition. 300 Plates and Diagrams. 
 
 12mo, cloth $1.40 
 
 "A copy of it should be kept for reference in every drawing office." — En- 
 gineering. 
 
 PATTERN MAKING. 
 
 Embracing the Main Types of Engineering Construction, and including 
 Gearing, Engine Work, Sheaves and Pulleys, Pipes and Columns, Screws, 
 Machine Parts, Pumps and Cocks, the Moulding of Patterns in Loam 
 and Greensand, Weight of Castings, &c. By J. G. Horner, A.M.I.M.E. 
 Third Edition, Enlarged. With 486 Illustrations. 12mo,cloth. $3 00 
 
MECHANICAL ENGINEERING, &c. 9 
 
 SMITHY AND FORGE. 
 
 Including the Farrier's Art and Coach Smithing. By W. J. E. Crane. 
 
 12mo, cloth $1.00 
 
 "The first modern English book on the subject. Great pains have been 
 bestowed by the author upon the book; shoeing-smiths will find it both 
 useful and interesting." 
 
 TOOTHED GEARING. 
 
 A Practical Handbook for Offices and Workshops. By J. Horner, 
 A.M.I.M.E. Second Edition, with a new Chapter on Recent Practice. 
 With 184 Illustrations. 12mo, cloth $2.25 
 
 MODERN WORKSHOP PRACTICE, 
 
 As applied to Marine, Land, and Locomotive Engines, Floating Docks, 
 Dredging Machines, Bridges, Shipbuilding, &c. By J. G. Winton. 
 Fourth Edition, Illustrated. 12mo, cloth $1.40 
 
 DETAILS OF MACHINERY. 
 
 Compriiing Instructions for the Execution of various Works in Iron in 
 the Fitting Shop, Foundry, and Boiler Yard. By Francis Campin, 
 CE. 12mo, cloth $1.20 
 
 ENGINEERING ESTIMATES, COSTS, AND ACCOUNTS. 
 
 A Guide to Commercial Engineering. With numerous examples of Es- 
 timates and Costs of Millwright Work, Miscellaneous Productions, 
 Steam Engines and Steam Boilers ; and a Section on the Preparation 
 of Costs Accounts. By A General Manager. Second Edition. 8vo, 
 cloth $4.50 
 
 MECHANICAL ENGINEERING. 
 
 Comprising Metallurgy, Moulding, Casting, Forging, Tools, Workshop 
 Machinery, Mechanical Manipulation, Manufacture of the Steam En- 
 gine, &c. By Francis Campin, CE. Third Edition. 12mo, cloth 
 
 $1.00 
 
 LATHE=WORK. 
 
 A Practical Treatise on the Tools. Appliances, and Processes employed in 
 the Art of Turning. By Paul N. Hasluck. Eighth Edition. 12mo, 
 
 cloth $2.00 
 
 "Written by a man who knows not only how work ought to be done, but 
 
 who also knows how to do it, and how to convey his knowledge to others." — 
 
 Engineering. 
 
 SCREW=TH READS, 
 
 And Methods of Producing Them. With numerous Tables and com- 
 plete Directions for using Screw-cutting Lathes. By Paul N. Hasluck. 
 Author of "Lathe-work," &c. Sixth Edition. Waistcoat-pocket size. 
 
 .60 
 "Full of useful information, hints and practical criticism. Tans, dies, 
 and screwing tools generally are illustrated and their action described." 
 
 CONDENSED MECHANICS. 
 
 A Selection of Formula 1 , Rules, Tables, and Data for the Use of Engi- 
 neering Students, &c. By W. G.C. Hughes, A.M.I.C.E. 12mo, cloth. 
 
 $1.00 
 
 MECHANICS OF AIR MACHINERY. 
 
 By Dr. J. Weisbach and Prof. G. Herrmann. Authorized Translation 
 with an Appendix on American Practice by A. Trowbridge, Ph.B., 
 Adjunct Professor of Mechanical Engineering, Columbia University. 
 Royal 8vo, cloth. Net $3.75 
 
io CROSBY LOCKWOOD &■ SON'S CATALOGUE. 
 PRACTICAL MECHANISM. 
 
 And Machine Tools. By T. Baker, C.E. With Remarks on Tools and 
 Machinery by J. Nasmyth, C.E. 12mo, cloth $1.00 
 
 MECHANICS. 
 
 Being a concise Exposition of the General Principles of Mechanical 
 Science and their Applications. By C. Tomlinson, F.R.S. 12mo, 
 cloth 60 
 
 FUELS: SOLID, LIQUID, AND GASEOUS. 
 
 Their Analysis and Valuation. For the use of Chemists and Engineers. 
 By H. J. Phillips, F.C.S., formerly Analytical and Consulting Chemist 
 to the Great Eastern Railway. Fourth Edition. 12mo, cloth.. .80 
 "Ought to have its place in the laboratory of every metallurgical estab- 
 lishment and wherever fuel is used on a large scale." — Chemical News. 
 
 FUEL, ITS COMBUSTION AND ECONOMY. 
 
 Consisting of an Abridgment of "A Treatise on the Combustion of Coal 
 
 and the Prevention of Smoke." By C. W. Williams, A. Inst. C.E. 
 
 With extensive Additions by D. Kinnbar Clark, M.Inst. C.E. 
 
 Fourth Edition. 12mo, cloth $1.50 
 
 "Students should buy the book and read it, as one of the most complete 
 and satisfactory treatises on the combustion and economy of fuel to be 
 had." — Engineer. 
 
 STEAM AND THE STEAM ENGINE, 
 
 Stationary and Portable. Being an Extension of the Treatise on the 
 Steam Engine of Mr. J. Sewbll. By D. K. Clark, C.E. Fourth Edi- 
 tion. 12mo, cloth $1.40 
 
 "Every essential part of the subject is treated of competently, and in a 
 popular style." 
 
 PUMPS AND PUMPING. 
 
 A Handbook for Pump Users. Being Notes on Selection, Construction, 
 and Management. By M. Powis Bale, M.Inst. C.E. , M.I.Mech.E. 
 
 Fourth Edition. 12mo, cloth $1.50 
 
 " Thoroughly practical and clearly written." 
 
 REFRIGERATION, COLD STORAGE, & ICE=MAKING. 
 
 A Practical Treatise on the Art and Science of Refrigeration. By. A. 
 J. Wallis-Tatler, A.M. Inst. C.E. , Author of "Refrigerating and Ice- 
 Making Machinerv." 600 pp., with 360 Illustrations. Medium 8vo, 
 
 cloth $4.50 
 
 Contents: — Chapter I. Introduction. — II. The Theory and Prac- 
 tice op Refrigeration. — III. The Liquefaction Process. — IV. The 
 Vacuum Process. — V. The Compression Process or System. — VI. The 
 Compression Process (Continued). — VII. The Compression Process (Con- 
 tinued). — VIII. Condensers and Water-Cooling and Saving Apparatus. 
 — IX. The Absorption and Binary Absorption Process or System. — 
 X. The Cold-Air System. — XI. Cocks, Valves and Pipe-Joints and 
 Unions. — XII. Refrigeration and Cold Storage. — XIII. Refrigera- 
 tion and Cold Storage (Continued). — XIV. Refrigeration and Cold 
 Storage (Continued). — XV. Refrigeration and Cold Storage (Con- 
 tinued). — XVI. Marine Refrigeration. — XVII. Manufacturing, In- 
 dustrial and Constructional Applications. — XVIII. Ice-Making. — 
 
 XIX. The Management and Testing of Refrigerating Machinery. — 
 
 XX. Cost of Working. — XXI. The Production of Very Low Temper- 
 atures. — XXII. Useful Tables and Memoranda. — Appendix. — Bibli- 
 ography of Refrigeration. 
 
CIVIL ENGINEERING, SURVEYING, &c. n 
 
 THE POCKET BOOK OF REFRIGERATION AND ICE- 
 MAKING. 
 
 By A. J. Wallis-Tayler, A.M. Inst. C.E. Author of "Refrigerating 
 and Ice-making Machinery," &c. Third Edition, Enlarged. 12mo 
 cloth $1.50 
 
 REFRIGERATING & ICE=MAKING MACHINERY. 
 
 A Descriptive Treatise for the Use of Persons Employing Refrigerating 
 and Ice-making Installations, and others. By A. X Wallis-Tayler, 
 
 A.M.Inst.C.E. Third Edition, Enlarged. 12mo, cloth $3.00 
 
 "May be recommended as a useful description of the machinery, the proc- 
 esses, and of the acts, figures, and tabulated physics of refrigerating." — En- 
 gineer. 
 
 MOTOR VEHICLES FOR BUSINESS PURPOSES. 
 
 A Practical Handbook for those interested in the Transport of Passen- 
 gers and Goods. By A. J. Wallis-Tayler, A.M.Inst.C.E. With 134 
 Illustrations. Demy 8vo, cloth [Just published.] $3.50 
 
 MOTOR CARS OR POWER=CARRIAGES FOR COMMON 
 ROADS. 
 
 By A. i. Wallis-Tayler, A.M.Inst.C.E. 212 pp., with 76 Illustrations. 
 12mo, cloth $2.00 
 
 AERIAL NAVIGATION. 
 
 A Practical Handbook on the Construction of Dirigible Balloons, Aero- 
 stats, Aeroplanes, and Aeromotors. By Frederick Walker, C.E., 
 Associate Member of the Aeronautic Institute. With 104 Illustrations. 
 Large 12mo, cloth $3.00 
 
 STONE=WORKING MACHINERY. 
 
 A Manual dealing with the Rapid and Economical Conversion of Stone. 
 With Hints on the Arrangement and Management of Stone Works. By 
 M. Powis Bale, M.Inst.C.E., M.I.Mech.E. Second Edition, enlarged. 
 
 12mo, cloth $3.50 
 
 "The book should be in the hands of every mason or student of stone- 
 work." 
 
 "A handbook for all who manipulate stone for building or ornamental 
 purposes." 
 
 FIRES, FIRE=ENGINES, AND FIRE BRIGADES. 
 
 With a History of Fire-Engines, their Construction, Use, and Manage- 
 ment; Foreign Fire Systems; Hints on Fire-Brigades, &c. By C. F. 
 T. Young, C.E. 8vo, cloth $8.00 
 
 CRANES. 
 
 The Construction of, and other Machinery for Raising Heavy Bodies 
 for the Erection of Buildings, &c. By J. Glynn, F.R.S. 12mo, cloth. 
 
 .60 
 
 CIVIL ENGINEERING, SURVEYING, ETC. 
 PIONEER IRRIGATION. 
 
 A Manual of Information for Farmers in the Colonies. By E. O. Maw- 
 son, M.Inst.C.E., Executive Engineer, Public Works Department, 
 Bombay. With Additional Chapters on Light Railways by E. R. 
 Calthrop, M.Inst.C.E., M.I.M.E. Illustrated by numerous Plates 
 
 and Diagrams. Demy 8vo, cloth $4.00 
 
 Summary of Contents : — Value of Irrigation, and Sources of Water 
 Supply. — Dams and Weirs. — Canals. — Underground Water. — Meth- 
 ods of Irrigation. — Sewage Irrigation. — Imperial Automatic Sluice 
 Gates. — The Cultivation of Irrigated Crops, Vegetables, and Fruit 
 Trees. — Light Railways for Heavy Traffic. — Useful Memoranda and 
 Data. 
 
12 CROSBY LOCKwfiOD &• SON'S CATALOGUE. 
 THE RECLAMATION OF LAND FROM TIDAL WATERS. 
 
 A Handbook for Engineers, Landed Proprietors, and others interested 
 in Works of Reclamation. By A. Beazely, M.Inst.C.E. 8vo, cloth. 
 
 $4.00 
 "The book shows in a concise way what has to be done in reclaiming land 
 from the sea, and the best way of doing it. Contains a great deal of prac- 
 tical and useful information which cannot fail to be of service to engineers 
 entrusted with the enclosure of salt marshes, and to landowners intending 
 to reclaim land from the sea." — The Engineer. 
 
 THE WATER SUPPLY OF TOWNS AND THE C0N= 
 STRUCTION OF WATER-WORKS. 
 
 A Practical Treatise for the Use of Engineers and Students of Engineer- 
 ing. By W. K. Burton, A.M. Inst. C.E., Consulting Engineer to the 
 Tokyo Water- works. Second Edition, Revised and Extended. With 
 numerous Plates and Illustrations. Super-royal 8vo, buckram. §9.00 
 I. Introductory. — II. Different Qualities of Water. — III. Quan- 
 tity of Water to be Provided. — IV. On Ascertaining whether a Pro- 
 posed Source of Supply is Sufficient. — V. On Estimating the Storage 
 Capacity Required to be Provided. — VI. Classification of Water- 
 works. — VII. Impounding Reservoirs. — VIII. Earthwork Dams. — IX. 
 Masonry Dams. — X. The Purification of Water. — XL Settling Res- 
 ervoirs. — XII. Sand Filtration. — XIII. Purification of Water by 
 Action of Iron, Softening of Water by Action of Lime, Natural 
 Filtration. — XIV. Service or Clean Water Reservoirs — Water 
 Towers — Stand Pipes. — XV. The Connection of Settling Reservoirs, 
 Filter Beds and Service Reservoirs. — XVI. Pumping Machinery. — 
 
 XVII. Flow of Water in Conduits — Pipes and Open Channels. — 
 
 XVIII. Distribution Systems. — XIX. Special Provisions for the Ex- 
 tinction of Fire. — XX. Pipes for Water-works. — XXI. Prevention 
 of Waste of Water. — XXII. Various Appliances used in Connection 
 with Water-works. 
 
 Appendix I. By Prof. JOHN MILNE, F.R.S. — Considerations Con- 
 cerning the Probable Effects of Earthquakes on Water- works, and 
 the Special Precautions to be Taken in Earthquake Countries. 
 
 Appendix II. By JOHN DE RIJKE, C.E.— On Sand Dunes and Dune 
 Sand as a Source of Water Supply. 
 
 THE WATER SUPPLY OF CITIES AND TOWNS. 
 
 By William Humber, A. M.Inst.C.E., and M.Inst.M.E., Author of 
 "Cast and Wrought Iron Bridge Construction," &c, &c. Illustrated 
 with 50 Double Plates, 1 Single Plate, Coloured Frontispiece, and up- 
 wards of 250 Woodcuts, and containing 400 pp. of Text. Imp. 4to, 
 
 elegantly and substantially half-bound in morocco $45.00 
 
 List of Contents: — I. Historical Sketch of some of the means that 
 have been adopted for the Supply of Water to Cities and Towns. — ■ 
 II. Water and the Foreign Matter usually associated with it. — III. 
 Rainfall and Evaporation. — IV. Springs and the Water-bearing 
 Formations of Various Districts. — V. Measurement and Estimation 
 of the Flow of Water. — VI. On the Selection of the Source of Sup- 
 ply. — VII. Wells. — VIII. Reservoirs. — IX. The Purification of 
 Water. — X Pumps. — XL Pumping Machinery. — XII. Conduits. — 
 XIII. Distribution of Water. — XIV. Meters, Service Pipes, and 
 House Fittings. — XV. The Law and Economy of Water-works. — XVI. 
 Constant and Intermittent Supply. — XVII. Description of Plates. — 
 Appendices, giving Tables of Rates of Supply, Velocities, &c, &c, 
 together with Specifications of Several Works Illustrated, among 
 which will be found: Aberdeen, Bideford, Canterbury, Dundee, 
 Halifax, Lambeth, Rotherham, Dublin, and others. 
 
 RURAL WATER SUPPLY. 
 
 A Practical Handbook on the Sunnlv of Water and Construction of 
 Water-works for small Countrv Districts. Bv Allan Greenwell, 
 A.M.Inst.C.E., and W. T. Curry, A.M.Inst.C.E., F.G.S. With Illus- 
 trations. Second Edition, Revised. 12mo, cloth $2.00 
 
CIVIL ENGINEERING, SURVEYING, &°c. 13 
 
 WATER ENGINEERING. 
 
 A Practical Treatise on the Measurement, Storage, Conveyance, and 
 Utilization of Water for the Supply of Towns, for Mill Power, and for 
 other Purposes. By Charles Slagg, A. M.Inst. C.E. Second Edition. 
 12mo, cloth $3.00 
 
 WATER WORKS, FOR THE SUPPLY OF CITIES AND 
 TOWNS. 
 
 With a Description of the Principal Geological Formations of England 
 as influencing Supplies of Water. By Samuel Hughes. 12mo cloth 
 
 $1.60 
 POWER OF WATER. 
 
 As applied to drive Flour Mills, and to give motion to Turbines, and 
 other Hydrostatic Engines. By Joseph Glynn, F.R.S., &c. New 
 Edition. Illustrated. 12mo, cloth < gQ 
 
 WELLS AND WELL=SINKING. 
 
 By J. G. Swindell, A.R.I.B.A., and G. R. Burnell, C.E. Revised 
 
 Edition. 12mo, cloth ^§q 
 
 "Solid practical information, written in a concise and lucid style. The 
 work can be recommended." 
 
 HYDRAULIC POWER ENGINEERING. 
 
 A Practical Manual on the Concentration and Transmission of Power 
 by Hydraulic Machinery. By G. Croydon Marks, A. M.Inst. C.E. 
 Second Edition, Enlarged, with about 240 Illustrations. 8vo, cloth. 
 
 [Just Published. $3.50 
 Summary op Contents: — Principles of Hydraulics. — The Flow op 
 Water. — Hydraulic Pressures. — Material. — Test Load. — Packings 
 for Sliding Surfaces. — Pipe Joints. — Controlling Valves. — Platform 
 Lifts. — Workshop and Foundry Cranes. — Warehouse and Dock 
 Cranes. — Hydraulic Accumulators. — Presses for Baling and other 
 Purposes. — Sheet Metal Working and Forging Machinery. — Hy- 
 draulic Riveters. — Hand and Power Pumps. — Steam Pumps. — Tur- 
 bines. — Impulse Turbines. — Reaction Turbines. — Design of Tur- 
 bines in Detail. — Water Wheels.— Hydraulic Engines. — Recent 
 Achievements. — Pressure of Water. — Action of Pumps, &c. 
 
 HYDRAULIC MANUAL. 
 
 Consisting of Working Tables and Explanatory Text. Intended as a 
 Guide in Hydraulic Calculations and Field Operations. By Lowis 
 D'A. Jackson, Author of "Aid to Survey Practice," "Modern Metrol- 
 ogy," &c. Fourth Edition, Enlarged. 8vo, cloth $8.00 
 
 "The author has constructed a manual which may be accepted as a trust- 
 worthy guide to this branch of the engineer's profession." — Engineering. 
 
 HYDRAULIC TABLES, CO=EFFICIENTS, & FORMUL/E. 
 
 For Finding the Discharge of Water from Orifices, Notches, Weirs, 
 Pipes, and Rivers. With New Formulae, Tables, and General Informa- 
 tion on Rain-fall, Catchment-Basins, Drainage, Sewerage, Water Sup- 
 ply for Towns and Mill Power. By John Neville, C.E. , M.R.I. A- 
 Third Edition, revised, with additions. Numerous Illustrations. 
 
 12mo, cloth $5.00 
 
 "It is, of all English books on the subject, the one nearest to complete- 
 ness." 
 
 MASONRY DAMS FROM INCEPTION TO COMPLETION. 
 
 Including numerous Formulae, Forms of Specifications and Tender, 
 Pocket Diagram of Forces, &c. For the use of Civil and Mining En- 
 gineers. By C. F. Courtney, M.Inst. C.E. 8vo, cloth $3.50 
 
 "Contains a good deal of valuable data. Many useful suggestions will be 
 
 found in the remarks on site and position, location of dam, foundations 
 
 and constuction." — Building News. 
 
i 4 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 RIVER BARS. 
 
 The Causes of their Formation, and their Treatment by "Induced Tidal 
 Scour"; with a Description of the Success! ui Reduction by this Method 
 of the Bar at Dublin. By I. J. Manx, Assist. Erig. to the Dublin Port 
 
 and Docks Board. Royal 8vo, cloth $3.00 
 
 "We recommend all interested in harbour works — and, indeed, those con- 
 cerned in the improvements of rivers generally — to read Mr. Mann's inter- 
 esting work." — Engineer. 
 
 DRAINAGE OF LANDS, TOWNS, AND BUILDINGS. 
 
 By G. D. Dempsey, C.E. Revised, with large Additions on Recent 
 Practice in Drainage Engineering by D. Kinnear Clark, M.Inst.C.E. 
 Fourth Edition. 12mo, cloth $1.80 
 
 SURVEYING AS PRACTISED BY CIVIL ENGINEERS 
 AND SURVEYORS. 
 
 Including the Setting-out of Works for Construction and Surveys 
 Abroad, with many Examples taken from Actual Practice. A Hand- 
 book for use in the Field and the Office, intended also as a Text-book 
 for Students. By John Whitelaw, Jun., A. M.Inst.C.E., Author of 
 "Points and Crossings." With about 260 Illustrations. I>emy 8vo, 
 doth $4.00 
 
 PRACTICAL SURVEYING. 
 
 A Text-book for Students preparing for Examination or for Survey- 
 work in the Colonies. By George W. Usill, A.M. Inst. C.E. Eighth 
 Edition, thoroughly Revised and Enlarged, by Aiex Beazeley, 
 M.Inst.C.E. With 4 Lithographic Plates and 360 Illustrations. 12mo, 
 cloth $3.00 
 
 SURVEYING WITH THE TACHEOMETER. 
 
 A practical Manual for the use of Civil and Military Engineers and Sur- 
 veyors, including two series of Tables specially computed for the Re- 
 duction of Readings in Sexagesimal and in Centesimal Degrees. By 
 Neil Kennedy, M.Inst.C.E. With Diagrams and Plates. Second 
 
 Edition. 8vo, cloth $4.00 
 
 "The work is very clearly written, and should remove all difficulties in the 
 way of any surveyor desirous of making use of this useful and rapid instru- 
 ment . ' ' — Nature. 
 
 LAND AND ENGINEERING SURVEYING. 
 
 For Students and Practical Use. Py T. Baker, C.E. Twentieth Edi- 
 tion, by F. E. Dixon, A.M. Inst. C.E. With Plates and Diagrams. 
 12mo, cloth 80 
 
 AID TO SURVEY PRACTICE. 
 
 For Reference in Surveying, Levelling, and Setting-out; and in Route 
 Surveys of Travellers by Land and Sea. With Tables, Illustrations, 
 and Records. By L. D'A. Jackson, A. M.Inst. C.E. Second Edition. 
 8vo, cloth $5.00 
 
 LAND AND MARINE SURVEYING. 
 
 In Reference to the Preparation of Plans for Roads and Railways; 
 Canals, Rivers, Towns' Water Supplies; Docks and Harbours. With 
 Description and Use of Surveying Instruments. By W. Davis Haskoll, 
 C.E. Second Edition, Revised with Additions. Crown 8vo, cloth. 
 
 $3.50 
 
CIVIL ENGINEERING, SURVEYING, &c. 15 
 
 ENGINEER'S & MINING SURVEYOR'S FIELD BOOK. 
 
 Consisting of a Series of Tables, with Rules, Explanations of Systems 
 and use of Theodolite for Traverse Surveying and plotting the work 
 with minute accuracy by means of Straight Edge and Set Square only; 
 Levelling with the Theodolite, Setting-out Curves with and without the 
 Theodolite, Earthwork Tables, &c. By W. Davis Haskoll, C.E. With 
 numerous Woodcuts. Fifth Edition, Enlarged. ]2mo, cloth. $4.50 
 "The book is very handy; the separate tables of sines and tangents to 
 
 every minute will make it useful for many other purposes, the genuine 
 
 traverse tables existing all the same." 
 
 AN OUTLINE OF THE METHOD OF CONDUCTING 
 A TRIGONOMETRICAL SURVEY. 
 
 For the Formation of Geographical and Topographical Maps and Plans, 
 Military Reconnaissance, LEVELLING, &c, with Useful Problems, 
 Formulae, and Tables. By Lieut. -General Fromb, R.E. I'ourth Edi- 
 tion, Revised and partly Re-written by Major-General Sir Charles 
 Warren, G.C.M.G., R.E. With 19 Plates and 115 Woodcuts. 8vo, 
 cloth $6.0O 
 
 PRINCIPLES AND PRACTICE OF LEVELLING. 
 
 Showing its Application to Purposes of Railway and Civil Engineering 
 in the Construction of Roads; with Mr. Telford's Rules for the same. 
 By Frederick W. Simms, M.Inst. C.E. Eighth Edition, with Law's 
 Practical Examples for Setting-out Railway Curves, and Trautwine's 
 Field Practice of Laying out Circular Curves. With 7 Plates and nu- 
 merous Woodcuts. 8vo $2.50 
 
 "The text-book on levelling in most of our engineering schools and col- 
 leges." — Engineer. 
 
 "The publishers have rendered a substantial service to the profession, 
 especially to the younger members, by bringing out the present edition of 
 Mr. Simm's useful work." — Engineering. 
 
 TABLES OF TANGENTIAL ANGLES AND MULTIPLES. 
 
 For Setting-out Curves from 5 to 200 Radius. By A. BsAzELEY.M.Inst. 
 C.E. 7th Edition, Revised. With an Appendix on the use of the 
 Tables for Measuring up Curves. Printed on 50 Cards, and sold in a 
 
 cloth box, waistcoat-pocket size $1.50 
 
 "Each table is printed on a small card, which, placed on the theodolite, 
 leaves the hands free to manipulate the instrument — no small advantage 
 as regards the rapidity of work." 
 
 "Very handy; aman may know that all his day's work must fall on two 
 of these cards, which he puts into his own card-case, and leaves the rest 
 behind." 
 
 PIONEER ENGINEERING. 
 
 A treatise on the Engineering Operations connected with the Settle- 
 ment of Waste Lands in New Countries. By E. Dobson, M.Inst. C.E. 
 
 Second Edition. 12mo, cloth $1.80 
 
 "Mr. Dobson is familiar with the difficulties which have to be overcome 
 
 in this class of work, and much of his advice will be valuable to young 
 
 engineers proceeding to our colonies." — Engineering. 
 
 TUNNELLING. 
 
 A Practical Treatise. By Charles Prelini, C.E. With additions by 
 Charles S. Hill, C.E. With 150 Diagrams and Illustrations. Royal 
 8vo, cloth $3.00 
 
 PRACTICAL TUNNELLING. 
 
 Explaining in detail Setting-out the Works, Shaft-sinking, and Heading- 
 driving, Ranging the Lines and Levelling underground, Sub-Excavat- 
 ing, Timbering and the Construction of the Brickwork of Tunnels. By 
 F. W. Simivo, M.Inst.C.E. Fourth Edition. Revised and Further Ex- 
 tended, including the most recent (1895) Examples of Sub-aqueous and 
 other Tunnels, bv D. Kinnear Clark, M.Inst.C.E With 34 Folding 
 Plates. Imperial 8vo, cloth $9.00 
 
16 CROSBY LOCKWOOD &• S02VS CATALOGUE. 
 EARTH AND ROCK EXCAVATION. 
 
 A Practical Treatise, by Charles Prelini, C.E. 365 pp., with Tables, 
 many Diagrams and Engravings. Royal 8vo, cloth. 
 
 [Just Published. $3.00 
 
 CONSTRUCTION OF ROADS AND STREETS. 
 
 By H. Law, C.E., and D. K. Clark, C.E. Sixth Edition, revised, with 
 Additional Chapters by A. J. Wallis-Tayler, A.M.Inst.C.E. 12mo, 
 cloth $2.50 
 
 TRAMWAYS: THEIR CONSTRUCTION AND WORKING. 
 
 Embracing a Comprehensive History of the System ; with an exhaustive 
 Analysis of the Various Modes of Traction, including Horse Power, 
 Steam, Cable Traction, Electric Traction, <fec; a Description of the 
 Varieties of Rolling Stock ; and ample Details of Cost and Working 
 Expenses. New Edition, Thoroughly Revised, and Including the 
 Progress recently made in Tramway Construction, <fec, &c. By D. 
 Kinnear Clark, M.Inst.C.E. With 400 Illustrations. 8vo, 780 pp., 
 buckram $7.50 
 
 HANDY GENERAL EARTH=WORK TABLES. 
 
 Giving the Contents in Cubic Yards of Centre and Slopes of Cuttings 
 and Embankments from 3 inches to 80 feet in Depth or Height, for use 
 with either 66 feet Chain or 100 feet Chain. By J. H. Watson Buck, 
 M.In3t.C.E. On a sheet mounted in cloth case $1.50 
 
 EARTHWORK TABLES. 
 
 Showing the Contents in Cubic Yards of Embankments. Cuttings, &c, 
 of Heights or Depths up to an average of 80 f eet. By Joseph Broad- 
 bent, C.E., and Francis Campin, C.E. 12mo, cloth $2.00 
 
 "The way in which accuracy is attained, by a simple division of each cross 
 
 section into three elements, two in which are constant and one variable, is 
 
 ingenious." 
 
 A MANUAL ON EARTHWORK. 
 
 By Alex. J. Graham, C.E. With numerous Diagrams. Second Edi- 
 tion. 18mo, cloth $1.00 
 
 THE CONSTRUCTION OF LARGE TUNNEL SHAFTS. 
 
 A Practical and Theoretical Essay. By J. H. Watson Buck, M.Inst. 
 C.E., Resident Engineer, L. and N. W. R. With Folding Plates, 8vo, 
 
 cloth $4.80 
 
 "Many of the methods given are of extreme practical value to the mason, 
 and the observations on the form of arch, the rules for ordering the stone, 
 and the construction of the templates, will be found of considerable use." 
 
 ESSAY ON OBLIQUE BRIDGES 
 
 (Practical and Theoretical.) With 13 large Plates. By the late George 
 Watson Buck, M.Inst.C.E Fourth Edition, revised by his Son, J. H. 
 Watson Buck, M.Inst C.E ; and with the addition of Description to 
 Diagrams for Facilitating the Construction of Oblique Bridges, by W. 
 H. Barlow, M.Inst.C.E Royal 8vo, cloth $4.80 
 
 CAST & WROUGHT IRON BRIDGE CONSTRUCTION 
 
 (A Complete and Practical Treatise on), including Iron Foundations 
 In Three Parts. — Theoretical, Practical, and Descriptive By Wil- 
 liam Humber, A.M.Inst.C.E , and M.Inst.M.E. Third Edition, revised 
 and much improved, with 115 Double Plates (20 of which now first 
 appear in this edition ), and numerous Additions to the Text In 2 vols., 
 imp. 4to, half-bound in morocco $50.00 
 
 IRON BRIDGES OF MODERATE SPAN: 
 
 Their Construction and Erection By H. W. Pendred With 40 Il- 
 lustrations. 12mo, cloth # §Q 
 
CIVIL ENGINEERING, SURVEYING, &c. 17 
 
 IRON AND STEEL BRIDGES AND VIADUCTS. 
 
 A Practical Treatise upon their Construction. For the use of Engi- 
 neers, Draughtsmen, and Students. By Francis Campin, C.E. 12mo, 
 cloth $1.40 
 
 TUBULAR AND OTHER IRON GIRDER BRIDGES, 
 
 Describing the Britannia and Conway Tubular Bridges. With a 
 Sketch of Iron Bridges, &c. By G. D. Dempsey, C.E. 12mo, cloth, 
 
 .80 
 
 GRAPHIC AND ANALYTIC STATICS. 
 
 In Their Practical Application to the Treatment of Stresses in Roofs, 
 Solid Girders, Lattice, Bowstring, and Suspension Bridges, Braced 
 Iron Arches and Piers, and other Frameworks. By R. Hudson 
 Graham, C.E. Containing Diagrams and Plates to Scale. With num- 
 erous Examples, many taken from existing Structures. Specially 
 arranged for Class-work in Colleges and Universities. Second Edition, 
 Revised and Enlarged. 8vo, cloth $6.00 
 
 WEIGHTS OF WROUGHT IRON & STEEL GIRDERS. 
 
 A Graphic Table for Facilitating the Computation of the Weights of 
 Wrought Iron and Steel Girders, &c, for Parliamentary and other 
 Estimates. By J. H. Watson Buck, M.Inst.C.E. On a sheet. $1.00 
 
 GEOMETRY FOR TECHNICAL STUDENTS. 
 
 An Introduction to Pure and Applied Geometry and the Mensuration 
 of Surfaces and Solids, including Problems in Plane Geometry useful in 
 Drawing. By E. H. Sprague, A.M.Inst.C.E. 12mo, cloth. . . .50 
 
 PRACTICAL GEOMETRY. 
 
 For the Architect, Engineer, and Mechanic. Giving Rules for the Delin- 
 eation and Application of various Geometrical Lines, Figures, and 
 
 Curves. By E. W. Tarn, M.A., Architect. 8vo, cloth $3.50 
 
 "No book with the same objects in view has ever been published in which 
 
 the clearness of the rules laid down and the illustrative diagrams have been 
 
 so satisfactory." — Scotsman. 
 
 THE GEOMETRY OF COMPASSES. 
 
 Or, Problems Resolved by the mere Description of Circles and the Use 
 of Coloured Diagrams and Symbols. By Oliver Byrne. Coloured 
 Plates. 12mo, cloth $1.50 
 
 MENSURATION AND MEASURING. 
 
 With the Mensuration and Levelling of Land for the purposes of Modern 
 Engineering. By T. Baker, C.E. New Edition by E. Nugent, C.E. 
 12mo, cloth .60 
 
 HANDY BOOK FOR THE CALCULATION OF STRAINS 
 
 In Girders and Similar Structures and their Strength. Consisting of 
 Formulae and Corresponding Diagrams, with numerous details for Prac- 
 tical Application, &c. By William Humber, A.M.Inst.C.E., &c. Sixth 
 Edition. 12mo, with nearly 100 Woodcuts and 3 Plates, cloth. $2.50 
 
 THE STRAINS ON STRUCTURES OF IRONWORK. 
 
 With Practical Remarks on Iron Construction. By F. W. Shields, 
 M.Inst.C.E. 8vo, cloth $2.00 
 
 CONSTRUCTIONAL IRON AND STEEL WORK, 
 
 As applied to Public, Private, and Domestic Buildings. By Francis 
 Campin, C.E. 12mo, cloth $1.40 
 
18 CROSBY LOCKWOOD &• SON'S CATALOGUE. 
 MATERIALS AND CONSTRUCTION. 
 
 A Theoretical and Practical Treatise on the Strains, Designing, and 
 Erection of Works of Construction. By Francis Campin, C.E. Third 
 
 Edition. 12mo, cloth as-i oft 
 
 "No better exposition of the practical application of the principles of 
 
 construction has yet been published to our knowledge in such a cheap 
 
 comprehensive form." — Building News. 
 
 EXPERIMENTS ON THE FLEXURE OF BEAMS. 
 
 Resulting in the Discovery of New Laws of Failure by Buckling. By 
 Albert E. Guy. Medium 8vo, cloth Net $1,25 
 
 TRUSSES OF WOOD AND IRON. 
 
 Practical Applications of Science in Determining the Stresses, Breaking 
 Weights, Safe Loads, Scantlings, and Details of Construction. With 
 Complete Working Drawings. By W. Griffiths, Surveyor. Oblong, 
 
 8vo, cloth. $1.80 
 
 "This handy little book enters so minutely into every detail connected 
 
 with the construction of roof trusses that no student need be ignorant of 
 
 these matters." — Practical Engineer. 
 
 CONSTRUCTION OF ROOFS, OF WOOD AND IRON: 
 
 Deduced chiefly from the Works of Robison, Tredgold, and Humber. 
 
 ByE.W. Tarn, M.A., Architect. Fourth Edition. 12mo, cloth. # g0 
 "Mr. Tarn is so thoroughly master of his subject, that although the trea- 
 tise was founded on the works of others he has given it a distinct value of 
 his own. It will be found valuable by all students." — Builder. 
 
 A TREATISE ON THE STRENGTH OF MATERIALS. 
 
 With Rules for Application in Architecture, the Construction of Sus- 
 pension Bridges, Railways, &c. By Peter Barlow, F.R.S. A new 
 Edition, revised by his Sons, P. W. Barlow, F.R.S., and W. H. Barlow. 
 F.R.S. ; to which are added, Experiments by Hodgkinson, Fairbairn, 
 and Kirkaldy; and Formulae for calculating Girders, &c. Edited by 
 Wm. Humber, A.M.Inst. C.E. 8vo, 400 pp., with 19 Plates and numer- 
 ous Woodcuts, cloth $7.00 
 
 "Valuable alike to the student, tyro, and the experienced practitioner, it 
 
 will always rank in future as it has hitherto done, as the standard treatise 
 
 on that particular subject." — Engineer. 
 
 EXPANSION OF STRUCTURES BY HEAT. 
 
 By John Keily, C.E., late of the Indian Public Works Department. 
 
 12mo, cloth $1.50 
 
 "The aim the author has set before him, viz., to show the effects of heat 
 upon metallic and other structures, is a laudable one, for this is a branch of 
 physics upon which the engineer or architect can find but little reliable and 
 comprehensive data in books."— Builder. 
 
 CIVIL ENGINEERING. 
 
 By Henry Law, M.Inst. C.E. Including a Treatise on Hydraulic En- 
 gineering by G. R. Burnell, M.Inst. C.E. Seventh Edition, revised, 
 with Large Additions on Recent Practice by D. Kinnear Clark, 
 M.Inst.C.E. 12mo, cloth $2.60 
 
 GAS WORKS, 
 
 Their Construction and Arrangement, and the Manufacture and Distri- 
 bution of Coal Gas. By S. Hughes, C.E. Ninth Edition. Revised, 
 with Notices of Recent Improvements by Henry O'Connor, A.M.Inst. 
 
 C.E. 12mo, cloth $2.40 
 
 "Of infinite service alike to manufacturers, distributors, and consumers." 
 
MARINE ENGINEERING, NAVIGATION, &c. i 9 
 PNEUMATICS, 
 
 Including Acoustics and the Phenomena of Wind Currents, for the use 
 of Beginners. By Charles Tomlinson, F.R.S. 12mo, cloth. # gQ 
 
 FOUNDATIONS AND CONCRETE WORKS. 
 
 With Practical Remarks on Footings, Planking, Sand, Concrete, B6ton, 
 Pile-driving, Caissons, and Cofferdams. By E. Dobson. 12mo. m QQ 
 
 BLASTING AND QUARRYING OF STONE, 
 
 For Building and other Purposes. With Remarks on the Blowing up of 
 Bridges. By Gen. Sir J. Burgoyne, K.C.B. 12mo, cloth. .. . # gQ 
 
 SAFE RAILWAY WORKING. 
 
 A Treatise on Railway Accidents, their Cause and Prevention; with a 
 Description of Modern Appliances and Systems. By Clement E. 
 
 Stretton, C.E. Third Edition, Enlarged. 12mo, cloth $1.50 
 
 "A book for the engineer, the directors, the managers; and, in short, all 
 
 who wishfor information on railway matters will find a perfect encyclopedia 
 
 in 'Safe Railway Working.'" — Railway Review. 
 
 MARINE ENGINEERING, SHIPBUILDING, 
 NAVIGATION, ETC. 
 
 MARINE ENGINES AND BOILERS. 
 
 Their Design and Construction. A Handbook for the Use of Students, 
 Engineers, and Naval Constructors. Based on the Work "Berechnung 
 und Konstruktion der Schiffsmaschinen und Kessel," by Dr. G. Bauer, 
 Engineer-in-Chief of the Vulcan Shipbuilding Yard, Stettin. Translated 
 from the Second German Edition by E. M. Donkin, and S. Bryan 
 Donkin, A. M.I. C.E. Edited by Leslie S. Robertson, Secretary to 
 the Engineering Standards Committee, M.I.C.E., M.I.M.E., M.I.N. A., 
 &c. With numerous Illustrations and Tables. Thick 8vo, cloth, 
 
 [Just Published. $9.00 
 Summary of Contents:— PART I.— MAIN ENGINES.— Determina- 
 tion of Cylinder Dimensions. — The Utilisation of Steam in the En- 
 gine. — Stroke of Piston. — Number of Revolutions. — Turning Moment. 
 — Balancing of the Moving Parts. — Arrangement of Main Engines. — 
 Details of Main Engines. — The Cylinder. — Valves. — Various Kinds 
 of Valve Gear. — Piston Rods. — Pistons. — Connecting Rod and Cross- 
 head. — Valve Gear Rods. — Bed Plates. — Engine Columns. — Revers- 
 ing and Turning Gear. PART II. — PUMPS. — Air, Circulating Feed, 
 and Auxiliary Pumps. PART III.— SHAFTING, RESISTANCE OF 
 SHIPS, PROPELLERS.— Thrust Shaft and Thrust Block.— Tunnel- 
 Shafts and Plummer Blocks. — Shaft Couplings. — Stern Tube. — The 
 Screw Propeller. — Construction of the Screw. PART IV. — PIPES 
 AND CONNECTIONS.— General Remarks, Flanges, Valves, &c— 
 Under Water Fittings. — Main Steam, Auxiliary Steam, and Exhaust 
 Piping. — Feed Water, Bilge, Ballast and Circulating Pipes. PART 
 V. — STEAM BOILERS. — Firing and the Generation of Steam. — 
 Cylindrical Boilers. — Locomotive Boilers. — Water-tube Boilers. — 
 Small Tube Water-Tube Boilers. — Smoke Box. — Funnel and Boiler 
 Lagging. — Forced Draught. — Boiler Fittings and Mountings. 
 PART VI.— MEASURING INSTRUMENTS. PART VII.— VARIOUS 
 DETAILS. — Bolts, Nuts, Screw Threads, &c. — Platforms, Gratings, 
 Ladders. — Foundations. — Seatings. — Lubrication. — Ventilation of 
 Engine Rooms. — Rules for Spare Gear. PART VIII. — ADDITIONAL 
 TABLES. 
 
20 CROSBY LOCKWOOD &• SON'S CATALOGUE. 
 
 THE NAVAL ARCHITECT'S AND SHIPBUILDER'S 
 POCKET=BOOK 
 
 Of Formulae, Rules, and Tables, and Marine Engineer's and Surveyor's 
 Handy Book of Reference. By Clement Mackrow, M.I.N. A. Eighth 
 Edition, carefully Revised and Enlarged. Fcap, leather. . Net $5.00 
 Summary of Contents: — Signs and Symbols, Decimal Fractions. — 
 Trigonometry. — Practical Geometry. — Mensuration. — Centres and 
 Moments op Figures. — Moments op Inertia and Radii Gyration. — Al- 
 gebraical Expressions for Simpson's Rules. — Mechanical Principles. 
 — Centre op Gravity. — Laws of Motion. — Displacement, Centre of 
 Buoyancy. — Centre of Gravity of Ships' Hull. — Stability Curves and 
 Metacentres. — Sea and Shallow-water Waves.— Rolling of Ships. — 
 Propulsion and Resistance of Vessels. — Speed Trials. — Sailing, Cen- 
 tre op Effort. — Distances down Rivers, Coast Lines. — Steering and 
 Rudders of Vessels. — Launching Calculations and Velocities. — 
 Weight op Material and Gear. — Gun Particulars and Weight. — 
 Standard Gauges. — Riveted Joints and Riveting. — Strength and 
 Tests op Materials. — Binding and Shearing Stresses. — Strength of 
 Shafting, Pillars, Wheels, &c. — Hydraulic Data, &c. — Conic Sec- 
 tions, Catenarian Curves. — Mechanical Powers, Work. — Board of 
 Trade Regulations for Boilers and Engines. — Board op Trade Reg- 
 ulations for Ships. — Lloyd's Rules for Boilers. — Lloyd's Weight of 
 Chains. — Lloyd's Scantlings for Ships. — Data of Engines and Ves- 
 sels. — Ships' Fittings and Tests. — Seasoning Preserving Timber. — 
 Measurement of Timber. — Alloys, Paints, Varnishes. — Data for Stow- 
 age. — Admiralty Transport Regulations. — Rules for Horse-power, 
 Screw Propellers, &c. — Percentages for Butt Straps. — Particulars 
 of Yachts. — Masting and Rigging. — Distances of Foreign Ports. — 
 Tonnage Tables.— Vocabulary op French and English Terms. — English 
 Weights and Measures. — Foregn Weights and Measures. — Decimal 
 Equivalents. — Useful Numbers. — Circular Measures. — Areas of and 
 Circumferences of Circles. — Areas of Segments of Circles. — Tables 
 of Squares and Cubes and Roots of Numbers. — Tables of Logarithms 
 of Numbers. — Tables op Hyberpolic Logarithms. — Tables of Natural 
 Sines, Tangents. — Tables of Logarithmic Sines, Tangents, &c. 
 
 WANNAN'S MARINE ENGINEER'S GUIDE 
 
 To Board of Trade Examinations for Certificates of Competency. Con- 
 taining all Latest Questions to Date, with Simple, Clear, and Correct 
 Solutions; 302 Elementary Questions with Illustrated Answers, and 
 Verbal Questions and Answers; complete Set of Drawings with State- 
 ments completed. By A. C. Wannan, C.E., Consulting Engineer, and 
 E. W. I. Wannan, M.I.M.E., Certificated First Class Marine Engineer. 
 With numerous Engravings. Fourth Edition, Enlarged. 500 pages. 
 8vo, cloth $4.00 
 
 WANNAN'S MARINE ENGINEER'S POCKET=BOOK. 
 
 Containing Latest Board of Trade Rules and Dataf or Marine Engineers. 
 By A. C. Wannan. Third Edition, Revised, Enlarged, and Brought up 
 to Date. Square 18mo, with thumb Index, leather $2.00 
 
 MARINE ENGINES AND STEAM VESSELS. 
 
 By R. Murray, C.E. Eighth Edition, thoroughly Revised, with Addi- 
 tions by the Author and by George Carlisle, C.E. 12mo, cloth. $1.80 
 
 ELEMENTARY MARINE ENGINEERING. 
 
 A Manual for Young Marine Engineers and Apprentices. By J. S. 
 Brewer. 12mo, cloth .60 
 
 CHAIN CABLES AND CHAINS. 
 
 Comprising Sizes and Curves of Links, Studs, &c, Iron for Cables and 
 Chains, Chain Cable and Chain Making, Forming and Welding Links, 
 Strength of Cables and Chains, Certificates for Cables, Marking Cables, 
 Prices of Chain Cables and Chains, Historical Notes, Acts of Parlia- 
 ment, Statutory Tests, Charges for Testing, List of Manufacturers of 
 
MARINE ENGINEERING, NAVIGATION, &c 21 
 
 Cables, &c, &c. By Thomas W. Traill, F.E.R.N., M.Inst.C.E., En- 
 gineer-Surveyor-in-Chief , Board of Trade, Inspector of Chain Cable and 
 Anchor Proving Establishments, and General Superintendent, Lloyd's 
 . Committee on Proving Establishments. With numerous Tables, Illus- 
 trations, and Lithographic Drawings. Folio, cloth $15.00 
 
 THE SHIPBUILDING INDUSTRY OF GERMANY. 
 
 Compiled and Edited by G. Lehmann-Felskowski. With Coloured 
 Prints, Art Supplements, and numerous Illustrations throughout the 
 text. Super-royal 4to, cloth $4.20 
 
 SHIPS AND BOATS. 
 
 By W. Bland. With numerous Illustrations and Models. Tenth Edi- 
 tion. 12mo, cloth # g0 
 
 SHIPS FOR OCEAN AND RIVER SERVICE, 
 
 Principles of the Construction of. By H. A. Sommerfeldt. 12mo. 
 
 .60 
 
 AN ATLAS OF ENGRAVINGS 
 
 To iftustrate the above. Twelve large folding Plates. Royal 4to, 
 doth $3.00 
 
 NAVAL ARCHITECTURE. 
 
 An Exposition of the Elementary Principles. By J. Peake. 12mo. 
 doth $1.40 
 
 THE ART AND SCIENCE OF SAIL/MAKING. 
 
 By Samuel B. Sadler, Practical Sailmaker, late in the employment of 
 Messrs. Ratsey and Lapthorne, of Cowes and Gosport. Plates. 4to, 
 
 doth $5.00 
 
 "This extremely practical work gives a complete education in all the 
 branches of the manufacture, cutting out, roping, seaming, and goring. It 
 s copiously illustrated, and forms a first-rate text-book and guide." 
 
 SAILS AND SAIL=MAKING. 
 
 With Draughting, and the Centre of Effort of the Sails. Weights and 
 Sizes of Ropes; Masting, Rigging, and Sails of Steam Vessels, &c. By 
 R. Kipping, N.A. 12mo, cloth $1.00 
 
 MASTING, MAST=MAKING, AND RIGGING OF SHIPS. 
 
 Also Tables of Spars, Rigging, Blocks; Chain, Wire, and Hemp Ropes, 
 &c, relative to every class of vessels. By R. Kipping. 12mo, cloth, 
 
 .SO 
 SEA TERMS, PHRASES, AND WORDS 
 
 (Technical Dictionary of) used in the English and French Languages 
 (English- French, French-English). For the Use of Seamen, Engineers, 
 Pilots, Shipbuilders, Shipowners, and Ship-brokers. Compiled by W. 
 Pirrie, late of the African Steamship Company. Fcap, 8vo, cloth 
 
 limp $3.00 
 
 This volume will be highly appreciated by seamen, engineers, pilots, ship- 
 builders and shipowners. It will be found wonderfully accurate and com- 
 plete. 
 
 SAILOR'S SEA BOOK: 
 
 A Rudimentary Treatise on Navigation. By James Greenwood, B.A. 
 With numerous Woodcuts and Coloured Plates. New and Enlarged 
 
 Edition. By W. H. Rosser. 12mo, cloth $1.00 
 
 Is perhaps the best and simplest epitome of navigation ever compiled. 
 
 PRACTICAL NAVIGATION. 
 
 Consisting of the Sailor's Sea Book, by J. Greenwood and W. H. Rosser; 
 together with Mathematical and Nautical Tables for the Working of the 
 Problems, by H. Law, C.E., and Prof. J. R. Young $2.80 
 
22 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 NAVIGATION AND NAUTICAL ASTRONOMY, 
 
 In Theory and Practice. By Prof. J. R. Young. 12mo, cloth.$1.00 
 "A very complete, thorough, and useful manual for the young navigator." 
 
 MATHEMATICAL TABLES, 
 
 For Trigonometrical, Astronomical, and Nautical Calculations; to 
 which is prefixed a Treatise on Logarithms, by H. Law, C.E. With 
 Tables for Navigation and Nautical Astronomy. By Prof. J. R. Young. 
 12mo, cloth $1.60 
 
 MINING, METALLURGY, AND 
 COLLIERY WORKING. 
 
 THE OIL FIELDS OF RUSSIA AND THE RUSSIAN 
 
 PETROLEUM INDUSTRY. 
 
 A Practical Handbook on the Exploration, Exploitation, and Manage- 
 ment of Russian Oil Properties, including Notes on the Origin of Petro- 
 leum in Russia, a Description of the Theory and Practice of Liquid 
 Fuel, and a Translation of the Rules and Regulations concerning Rus- 
 sian Oil Properties. By A. Beeby Thompson, A.M.I.M.E., late Chief 
 Engineer and Manager of the European Petroleum Company's Russian 
 Oil Properties. About 500 pp. With numerous Illustrations and 
 Photographic Plates, and a Map of the Balakhany-Saboontchy-Romany 
 Oil Field. Royal 8vo, cloth Net $ 7.50 
 
 MECHANICS OF AIR MACHINERY. 
 
 By Dr. J. Weisbach and Prof. G. Herrmann. Authorized Translation 
 with an Appendix on American Practice by A. Trowbridge, Ph.B., 
 Adjunct Professor of Mechanical Engineering, Columbia University. 
 
 Royal 8vo, cloth [Just Published. Net $3.7o 
 
 Summary of Contents : — The Movement of Air. — Natural and Arti- 
 ficial Ventilation. — Blowing-Engines; — Vacuum Pumps; Tuyeres; 
 Hot-air Blast; Work Performed by Blowers; Blast-reservoirs; 
 Piston-blowers. — Compressors. — Rotary Blowers. — Fans. — Recent 
 American Practice, &c. 
 
 MACHINERY FOR METALLIFEROUS MINES. 
 
 A Practical Treatise for Mining Engineers, Metallurgists, and Managers 
 of Mines. By E. Henry Da vies, M.E., F.G.S. 600 pp. With Fold- 
 ing Plates and other Illustrations. Medium 8vo, cloth $8.00 
 
 "Deals exhaustively with the many and complex details which go to 
 make up the sum total of machinery and other requirements for the success- 
 ful working of metalliferous mines, and as a book of ready reference is of 
 the highest value to mine managers and directors." — Mining Journal. 
 
 THE DEEP LEVEL MINES OF THE RAND, 
 
 And their Future Development, considered from the Commercial Point 
 oi View. By G. A. Denny (of Johannesburg), M.N.E.I.M.E., Con- 
 sulting Engineer to the General Mining and Finance Corporation, Ltd., 
 of London, Berlin, Paris, and Johannesburg. Fully Illustrated with 
 
 Diagrams and Folding Plates. Royal 8vo, buckram $10.00 
 
 "Mr. Denny by confining himself to the consideration of the future of the 
 deep-level mines of the Rand breaks new ground, and by dealing with the 
 subject rather from a commercial standpoint than from a scientific one, 
 appeals to a wide circle of readers. The book cannot fail to prove of very 
 great value to investors in South African mines." — Mining Journal. 
 
MINING, METALLURGY, & COLLIERY WORKING. 23 
 PROSPECTING FOR GOLD. 
 
 A Handbook of Practical Information and Hints for Prospectors based 
 on Personal Experience. By Daniel J. Rankin, F.R.S.G.S., M.R.A.S., 
 formerly Manager of the Central African Company, and Leader of 
 African Gold Prospecting Expeditions. With Illustrations specially 
 
 Drawn and Engraved for the Work. Fcap. 8vo, leather $L$.0l) 
 
 " This well-compiled book contains a collection of the richest gems of use- 
 ful knowledge for the prospector's benefit. A special table is given to 
 accelerate the spotting at a glance of minerals associated with gold." — Min- 
 ,ng Journal. 
 
 THE METALLURGY OF GOLD. 
 
 A Practical Treatise on the Metallurgical Treatment of Gold-bearing 
 Ores. Including the Assaying, Melting, and Refining of Gold. By M. 
 Eissler, M.Inst.M.M. Fifth Edition, Enlarged. With over 300 Illus- 
 trations and numerous Folding Plates. Medium 8vo, cloth. . • Jjj>7.50 
 "This book thoroughly deserves its title of a 'Practical Treatise.' The 
 whole process of gold mining, from the breaking of the quartz to the assay 
 of the bullion, is described in clear and orderly narrative and with much 
 fulness oWetail." 
 
 THE CYANIDE PROCESS OF GOLD EXTRACTION, 
 
 And its Practical Application on the Witwatersrand Gold Fields and 
 elsewhere. By M. Eissler, M.Inst.M.M. With Diagrams and Work- 
 ing Drawings, Third Edition, Revised and Enlarged. 8vo, cloth, 
 
 $3.00 
 
 "This book is just what was needed to acquaint mining men with the 
 actual working of a process which is not only the most popular, but is, as 
 a general rule, the most successful for the extraction of gold from tailings." 
 — Mining Journal. 
 
 DIAMOND DRILLING FOR GOLD & OTHER MINERALS. 
 
 A Practical Handbook on the Use of Modern Diamond Core Drills in 
 Prospecting and Exploiting Mineral-Bearing Properties, including Par- 
 ticulars of the Costs of Aoparatus and Working. By G. A. Denny, 
 M.N.E.Inst.M.E., M.Inst.M.M. Medium 8vo, 168 pp., with Illustra- 
 tive Diagrams $5.00 
 
 "There is certainly scopo for a work on diamond drilling, and Mr. Denny 
 
 deserves grateful recognition for supplying a decided want." — Mining 
 
 Journal. - 
 
 GOLD ASSAYING. 
 
 A Practical Handbook, giving the Modus Operandi for the Accurate 
 Assay of Auriferous Ores and Bullion, and the Chemical Tests required 
 in the Processes of Extraction by Amalgamation, Cyanidation, and 
 Chlorination. With an Appendix of Tables and Statistics. By H. 
 Joshua Phillips, F.I.C., F.C.S., Assoc Inst.C.E., Author of "Engineer- 
 ing Chemistry," <kc. With numerous Illustrations. 12mo, cloth. $3.00 
 
 FIELD TESTING FOR GOLD AND SILVER. 
 
 A Practical Manual for Prospectors and Miners. By W. H. Merritt, 
 M.N.E.Inst.M.E., A.R.S.M., &c. With Photographic Plates and other 
 
 Illustrations. Fcap. 8vo, leather $1.50 
 
 'As an instructor of prospectors' classes Mr. Merritt has the advantage of 
 knowing exactlv the information likely to be most valuable to the miner 
 in the field. The contents cover all the details for sampling and testing 
 gold and silver ores. A useful addition to a prospector's kit." — Mining 
 Journal. 
 
24 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
 THE PROSPECTOR'S HANDBOOK. 
 
 A Guide for the Prospector and Traveller in search of Metal-Bearing or 
 other Valuable Minerals. By J. W. Anderson, M.A.(Camb.)> F.R.G.S. 
 
 Tenth Edition. 12mo, cloth $1 .50 
 
 "How to find commercial minerals, and how to identify them when they 
 
 are found, are the leading points to which attention is directed." — Mining 
 
 Journal. 
 
 THE METALLURGY OF SILVER. 
 
 A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
 of Silver Ores. Including the Assaying, Melting, and Refining of Silver 
 Bullion. By M. Eisslek, M.Inst.M.M. Fifth Edition. 12mo, cloth. 
 
 $4.00 
 
 "A practical treatise and a technical work which we are convinced will 
 
 supply a long-felt want amongst practical men, and at the same time be of 
 
 value to students and others indirectly connected with the industries." — 
 
 Mining Journal. 
 
 THE HYDRO=METALLURQY OF COPPER. 
 
 Being an Account of Processes Adopted in the Hydro-Metallurgical 
 Treatment of Cupriferous Ores, Including the Manufacture of Copper 
 Vitriol, with ■ Chapters on the Sources of Supply of Copper and the 
 Roasting of Copper Ores. By M. Eissler, M.Inst.M.M. 8vo, cloth, 
 
 $4.50 
 "In this volume the various processes for the extraction of copper by wet 
 methods are fully detailed. Costs are given when available, and a great 
 deal of useful information about the copper industry of the world is pre- 
 sented in an interesting and attractive manner." — Mining Journal. 
 
 THE METALLURGY OF ARGENTIFEROUS LEAD. 
 
 A Practical Treatise on the Smelting of Silver-Lead Ores and the Refin- 
 ing of Lead Bullion. Including Reports on various Smelting Estab- 
 lishments and Descriptions of Modern Smelting Furnaces and Plants 
 in Europe and America. By M. Eissler, M.Inst.M.M. 12mo, cloth 
 
 $5.00 
 
 "The numerous metallurgical processes, which are fully and extensively 
 
 treated of, embrace all the stages experienced in the passage of the lead 
 
 from the various natural states to its issue from the refinery as an article 
 
 of commerce." — Practical Engineer. 
 
 METALLIFEROUS MINERALS AND MINING. 
 
 By D. C. Davies, F.G.S. Sixth Edition, thoroughly Revised and much 
 Enlarged by his Son, E. Henry Davies, M.E., F.G.S. 600 pp., with 
 
 173 Illustrations. 8vo, cloth Net $5.00 
 
 "Neither the practical miner nor the general reader, interested in mines, 
 can have a better book for his companion and his guide." — Mining Journal. 
 
 EARTHY AND OTHER MINERALS AND MINING. 
 
 By D. C. Davies, F.G.S., Author of "Metalliferous Minerals," &c. 
 Third Edition, Revised and Enlarged by his Son, E. Henry Davies, 
 M.E., F.G.S. With about 100 Illustrations. 12mo, cloth $5.00 
 
 BRITISH MINING. 
 
 A Treatise on the History, Discovery, Practical Development, and 
 Future Prospects of Metalliferous Mines in the United Kingdom. By 
 Robert Hunt, F R.S., late Keeper of Mining Records. Upwards of 
 950 pp., with 230 Illustrations. Second Edition, Revised. Super-royal 
 8vo, cloth $15.00 
 
 POCKET=BOOK FOR MINERS AND METALLURGISTS. 
 
 Comprising Rules, Formulae, Tables, and Notes for Use in Field and 
 Office Work. By F. Danvers Power, F.G.S., M.E. Second Edition, 
 Corrected. Fcap. 8vo, leather $3.50 
 
MINING, METALLURGY, &> COLLIERY WORKING. 25 
 THE MINER'S HANDBOOK. 
 
 A Handy Book of Reference on the subjects of Mineral Deposits, Mining 
 Operations, Ore Dressing, &c. For the Use of Students and others in- 
 terested in Mining Matters. Compiled by John Milne, F.R.S., Pro- 
 fessor of Mining in the Imperial University of Japan. Third Edition. 
 Fcap. 8vo, leather $3.00 
 
 IRON ORES of GREAT BRITAIN and IRELAND. 
 
 Their Mode of Occurrence, Age and Origin, and the Methods of Searching 
 for and Working Them. With a Notice of some of the Iron Ores of 
 Spain. By J. D. Kendall, F.G.S., Mining Engineer. 12mo, cloth 
 
 $6.00 
 METALLURGY OF IRON. 
 
 Containing History of Iron Manufacture, Methods of Assay, and Analy- 
 ses of Iron Ores, Processes of Manufacture of Iron and Steel, &c. By 
 H. Bauerman, F.G.S., A.R.S.M. With numerous Illustrations. Sixth 
 
 Edition, revised and enlarged. 12mo, cloth $2.00 
 
 "Carefully written, it has the merit of brevity and conciseness, as to less 
 
 important points; while all material matters are very fully and thoroughly 
 
 entered into." — Standard. 
 
 MINE 0RAINAGE. 
 
 A Complete Practical Treatise on Direct-Acting Underground Steam 
 Pumping Machinery. By Stephen Michell. Second Edition, Re- 
 written and Enlarged. With 250 Illustrations. Royal 8vo, cloth. 
 
 $10.00 
 HORIZONTAL PUMPING ENGINES— Rotary and Non-Rotary 
 Horizontal Engines. — Simple and Compound Steam Pumps. — VERTI- 
 CAL PUMPING ENGINES.— Rotary and Non-Rotary Vertical 
 Engines. — Simple and Compound Steam Pumps. — Triple-Expansion 
 Steam Pumps. — Pulsating Steam Pumps. — Pump Valves. — Sinking 
 Pumps, &c, &c. 
 
 ELECTRICITY AS APPLIED TO MINING. 
 
 By Arnold Lupton, M.Inst. C.E., M.I.M.E., M.I.E.E., late Professor of 
 Coal Mining at the Yorkshire College, Victoria University, Mining En- 
 gineer and Colliery Manager; G. D. Aspinall Parr, M.I.E.E., A.M.I. 
 M.E., Associate of the Central Technical College, City and Guilds of 
 London, Head of the Electrical Engineering Department, Yorkshire 
 College, Victoria University; and Herbert Perkin, M.I.M.E., Certifi- 
 cated Colliery Manager, Assistant Lecturer in the Mining Department of 
 the Yorkshire College, Victoria University. With about 170 Illustra- 
 tions. Second Edition, Revised and Enlarged. Medium 8vo, cloth. 
 
 [Just Published.] $4.50 
 (For Summary op Contents, see page 28.) 
 
 THE COLLIERY MANAGER'S. HANDBOOK. 
 
 A Comprehensive Treatise on the Laying-out and Working o'f Collieries, 
 Designed as a Book of Reference for Colliery Managers, and for the 
 Use of Coal-Mining Students preparing for First-class Certificates. By 
 Caleb Pamely, Mining Engineer and Surveyor; Member of the North 
 of England Institute of Mining and Mechanical Engineers ; and Member 
 of the South Wales Institute of Mining Engineers. With over 1,000 
 Diagrams, Plans, and other Illustrations. Fifth Edition, Carefully 
 Revised and Greatly Enlarged. 1,200 pp. Medium 8vo, cloth. $10.00 
 Geology. — Search for Coal. — Mineral Leases and other Holdings. — 
 Shaft Sinking. — Fitting Up the Shaft and Surface Arrangements. — 
 Steam Boilers and their Fittings. — Timbering and Walling. — Narrow 
 Work and Methods of Working. — Underground Conveyance. — Drain- 
 age. — The Gasks met with in Mines; Ventilation. — On the Friction of 
 Air in Mines. — The Priestman Oil Engine; Petroleum and Natural 
 Gas. — Surveying and Planning. — Safety Lamps and Firedamp Detect- 
 ors. — Sundry and Incidental Operations and Appliances. — Colliery 
 Explosions. — Miscellaneous Questions and Answers. — Appendix: 
 Summary of Report of H.M. Commissioners on Accidents in Mines, 
 
26 CROSBY LOCKWOOD 6* SON'S CATALOGUE. 
 PRACTICAL COALMINING. 
 
 An Elementary Class-Book for the Use of Students attending Classes in 
 Preparation for the Board of Education and County Council Examina- 
 tions, or Qualifying for First or Second Class Colliery Managers' Cer- 
 tificates. By. T. H. Cockin, Member ot the Institution of Mining 
 Engineers, Certificated Colliery Manager, Lecturer on Coal-Mining at 
 Sheffield University College. With Map of the British Coal-fields and 
 over 200 Illustrations specially Drawn and Engraved for the Work. 
 440 pp., 12mo, cloth $2.50 
 
 COLLIERY WORKING AND MANAGEMENT. 
 
 Comprising the Duties of a Colliery Manager, the Oversight and Arrange- 
 ment of Labour and Wages, and the different Systems of Working Coal 
 Seams. By H. F. Bulman and R. A. S. Redmayne. 350 pp., with 
 28 Plates and other Illustrations, including Underground Photographs. 
 Medium 8vo, cloth Net $6.00 
 
 NOTES AND FORMUL/E FOR MINING STUDENTS. 
 
 By John Herman Merivale, M.A., Late Professor of Mining in the 
 Durham College of Science, Newcastle-upon-Tyne. Fourth Edition, 
 Revised and Enlarged. By H. F. Btjlman, A.M. Inst. C.E. 12mo, 
 
 doth $1.00 
 
 "The author has done his work in a creditable manner, and has produced 
 
 a book that will be of service to students and those who are practically 
 
 engaged in mining operations." — Engineer. 
 
 PHYSICS AND CHEMISTRY OF MINING. 
 
 An Elementary Class-Book for the use of Students preparing for the 
 Board of Education and County Council Examinations in Mining, or 
 Qualifying for Colliery Managers' Certificates. By T. H. Byrom, 
 Chemist to the Wigan Coal and Iron Co., Ltd., &c. With Illustrations. 
 12mo, cloth [Just Published.] $1.50 
 
 MINING CALCULATIONS. 
 
 For the use of Students Preparing for the Examinations for Colliery 
 Managers' Certificates, comprising Numerous Rules and Examples in 
 Arithmetic, Algebra, and Mensuration. By T. A. O'Donahue, M.E., 
 First-class Certificated Colliery Manager. 12mo, cloth $1.50 
 
 COAL AND COAL MINING. 
 
 By the late Sir Warington W. Smyth, M.A., F.R.S. Eighth Edition, 
 Revised and Extended by T. Forster Brown, Chief Inspector of the 
 Mines of the Crown and of the Duchy of Cornwall. 12mo, cloth. $1.40 
 
 INFLAMMABLE GAS AND VAPOUR IN THE AIR 
 
 (The Detection and Measurement of). By Frank Clowes, D.Sc, 
 Lond., F.I.C. With a Chapter on The Detection and Measurement 
 of Petroleum Vapour, by Boverton Redwood, F.R.S.E. 12mo, 
 
 doth $2.50 
 
 ' ' Professor Clowes has given us a volume on a subject of much industrial 
 importance. . . Those interested in these matters may be recommended 
 to study this book, which is easy of comprehension and contains many good 
 things." — The Engineer. 
 
 COAL & IRON INDUSTRIES of the UNITED KINGDOM. 
 
 Comprising a Description of the Coal Fields and of the Principal Seams 
 of Coal, with Returns of their Produce and its Distribution, and Analyses 
 of Special Varieties. Also, an Account of the Occurrence of Iron Ore 
 in Veins or Seams; Analyses of each Variety; and a History of the 
 Rise and Progress of Pig Iron Manufacture. By Richard Meade. 8vo, 
 cloth $10.00 
 
MINING, METALLURGY, & COLLIERY WORKING. 27 
 MINING TOOLS, 
 
 Manual of. By W. Morgans, Lecturer on Mining at the Bristol School 
 of Mines. 12mo, cloth ffi ]_ t QQ 
 
 Atlas of Engravings to the above, containing 235 Illustrations drawn 
 to Scale. 4to $1.80 
 
 SLATE AND SLATE QUARRYING. 
 
 Scientific, Practical, and Commercial. By D. C. Davies, F.G.S., Min- 
 ing Engineer, &c. With numerous Illustrations and Folding Plates 
 Fourth Edition. 12mo, cloth $1.20 
 
 A FIRST BOOK OF MINING AND QUARRYING. 
 
 By J. H. Collins, F.G.S. Crown 8vo, cloth t g Q 
 
 ASBESTOS AND ASBESTIC. 
 
 Their Properties, Occurrence, and Use. By Robert H. Jones, F.S.A. 
 Mineralogist, Hon. Mem. Asbestos Club, Black Lake, Canada. With 
 Ten Collotype Plates and other Illustrations. Demy 8vo, cloth. $6.40 
 
 GRANITES AND OUR GRANITE INDUSTRIES. 
 
 By George F. Harris, F.G.S. With Illustrations. 12mo, cloth. $1.00 
 
 MINERAL SURVEYOR AND VALUER'S GUIDE. 
 
 Comprising a Treatise on Improved Mining Surveying and the Valuation 
 of Mining Properties, with New Traverse Tables. By W. Lintern, C.E. 
 
 Fourth Edition, enlarged. 12mo, cloth $1.40 
 
 "Contains much valuable information, and is thoroughly trustworthy." — 
 Iron and Coal Trades Review. 
 
 TRAVERSE TABLES. 
 
 For use in Mine Surveying. By William Lintern, C.E. With two 
 plates. Small crown 8vo, cloth Net $1.50 
 
 SUBTERRANEOUS SURVEYING. 
 
 By T. Fenwick. Also the Method of Conducting Subterraneous Sur- 
 veys without the use of the Magnetic Needle, &c. By T.Baker. 12mo, 
 
 $1.00 
 
 MINERALOGY, 
 
 Rudiments of. By A. Ramsay, F.G.S. Fourth Edition. Woodcuts 
 and Plates. 12mo, cloth $1.40 
 
 PHYSICAL GEOLOGY, 
 
 Partly based on Major-General Portlock's "Rudiments of Geology." 
 By Ralph Tate, A.L.S., &c. Woodcuts. 12mo, cloth .80 
 
 HISTORICAL GEOLOGY, 
 
 Partly based on Major-General Portlock's "Rudiments." By Ralph 
 Tate. 12mo, cloth $1.00 
 
 GEOLOGY, 
 
 Physical and Historical. Consisting of "Physical Geology," which 
 sets forth the Leading Principles of the Science; and "Historical Geol- 
 ogy," which treats of the Mineral and Organic Conditions of the Earth 
 at each successive epoch. By R. Tate. 12mo, cloth $1.80 
 
28 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 
 ELECTRICITY, ELECTRICAL 
 ENGINEERING, ETC. 
 
 THE ELEMENTS OF ELECTRICAL ENGINEERING. 
 
 A First Year's Course for Students. By Tyson Sewell, A.I.E.E., 
 Assistant Lecturer and Demonstrator in Electrical Engineering at the 
 Polytechnic, Regent Street, London. Third Edition, Revised and En- 
 larged, including an Appendix of Questions and Answers. 460 pages, 
 with 274 Illustrations. Demy 8vo, cloth. . . .[Just Published.] §3.00 
 Ohm's Law. — Units Employed in Electrical Engineering. — Series, 
 and Parallel Circuits; Current Density and Potential Drop in the. 
 Circuit. — The Heating Effect of the Electric Current. — The Mag- 
 netic Effect of an Electric Current. — The Magnetisation of Iron. — 
 Electro-Chemistry; Primary Batteries. — Accumulators. — Indicat- 
 ing Instruments; Ammeters, Voltmeters, Ohmmeters. — Electricity 
 Supply Meters. — Measuring Instruments, and the Measurement of 
 Electrical Resistance. — Measurement of Potential Difference 
 Capacity Current Strength, and Permeability. — Arc Lamps. — Incan- 
 descent Lamps, Manufacture and Installation; Photometry. — The 
 Continuous Current Dynamo. — Direct Current Motors. — Alternating 
 Currents. — Transformers, Alternators, Synchronous Motors. — Poly- 
 phase Working. — Appendix of Questions and Answers. 
 
 ELEMENTARY ELECTRICAL ENGINEERING 
 
 In Theory and Practice. A Class-book for Junior and Senior Students 
 and Working Electricians. By J. H. Alexander, M.B., A.I.E.E 
 With 181 Illustrations. 12mo, cloth [Just Published. $1.50 
 
 THE ELECTRICAL TRANSMISSION OF ENERGY. 
 
 A Manual for the Design of Electrical Circuits. By Arthur Vaughan 
 Abbott, C.E., Member American Institute of Electrical Engineers, 
 Member American Institute of Mining Engineers, Member American 
 , Society of Civil Engineers, Member American Society of Mechanical 
 Engineers, &c. With Ten Folding Diagrams and Sixteen Full-page 
 Engravings. Fourth Edition, entirely Re- Written and Enlarged. 
 Royal 8vo, cloth Net $5.00 
 
 ELECTRICITY AS APPLIED TO MINING. 
 
 By Arnold Lupton, M.Inst.C.E., M.I.M.E., M.I.E.E., late Professor of 
 Coal Mining at the Yorkshire College, Victoria University, Mining En- 
 gineer and Colliery Manager; G. D. Aspinall Parr, M.I.E.E., A.M.I. 
 M.E., Associate of the Central Technical College, City and Guilds of 
 London, Head of the Electrical Engineering Department, Yorkshire 
 College, Victoria University; and Herbert Perkin, M.I.M.E., Cer- 
 tificated Colliery Manager, Assistant Lecturer in the Mining Depart- 
 ment of the Yorkshire College, Victoria University. With about 170 
 Illustrations. Second Edition, Revised and Enlarged, Medium 8vo, 
 
 cloth [Just Published. $4.50 
 
 Introductory. — Dynamic Electricity. — Driving of the Dynamo. — 
 The Steam Turbine. — Distribution of Electrical Energy. — Starting 
 and Stopping Electrical Generators and Motors. — Electric Cables. — 
 Central Electrical Plants. — Electricity applied to Pumping and 
 Hauling. — Electricity applied to Coal-cutting. — Typical Electric 
 Plants Recently Erected. — Electric Lighting by Arc and Glow 
 Lamps. — Miscellaneous Applications of Electricity. — Electricity as 
 Compared with other modes of Transmitting Power. — Dangers of 
 Electricity. 
 
ELECTRICITY, ELECTRICAL ENGINEERING, &c. 29 
 CONDUCTORS FOR ELECTRICAL DISTRIBUTION. 
 
 Their Materials and Manufacture, The Calculation of Circuits, Pole-Line 
 Construction, Underground Working, and other Uses. By F. A. C. 
 Perbine, A.M., D.Sc; formerly Professor of Electrical Engineering, 
 Leland Stanford, Jr., University; M.Amer.I.E.E. 8vo, cloth. 
 
 Net $3.50 
 Conductor Materials. — Alloyed Conductors. — Manufacture of 
 Wire. — Wire-Finishing. — Wire Insulation. — Cables. — Calculation of 
 Circuits. — Kelvin's Law of Economy in Conductors. — Multiple Arc 
 Distribution. — Alternating Current Calculation. — Overhead Lines. 
 — Pole Line. — Line Insulators. — Underground Conductors. 
 
 DYNAMO ELECTRIC MACHINERY: its CONSTRUC= 
 TION, DESIGN, and OPERATION. 
 
 By Samuel Sheldon, A.M., Ph.D., Professor of Physics and Electrical 
 Engineering at the Polytechnic Institute of Brooklyn, assisted by H. 
 Mason. B.S. 
 
 In two volumes, sold separately, as follows: — 
 Vol. I.— DIRECT CURRENT MACHINES. Fifth Edition, Revised. 
 
 8vo. 280 pages, with 200 Illustrations -N^$2.50 
 
 Vol. U— ALTERNATING CURRENT MACHINES. 8vo. 260 pages, 
 
 with 184 Illustrations Net $2.50 
 
 Designed as Text-books for use in Technical Educational Institutions, and 
 by Engineers whose work includes the handling of Direct and Alternating 
 Current Machines respectively, and for Students proficient in mathematics. 
 
 DYNAMO, MOTOR AND SWITCHBOARD CIRCUITS 
 FOR ELECTRICAL ENGINEERS. 
 
 A Practical Book dealing with the subject of Direct, Alternating and 
 Polyphase Currents. By William R. Bowker, C.E., M.E., E.E., Con- 
 sulting Tramway Engineer. 8vo, cloth $2.25 
 
 "Mr. Bowker's book consists chiefly of diagrams of connections, with short 
 explanatory notes, there are over 100 diagrams, and the cases considered 
 cover all the more important circuits, whether in direct current, single- 
 phase, or polyphase work." — Nature. 
 
 ARMATURE WINDINGS OF DIRECT CURRENT 
 DYNAMOS. 
 
 Extension and Application of a General Winding Rule. By E. Arnold, 
 Translated from the German by F. B. De Grees. 8vo, cloth. $2.00 
 
 POWER TRANSMITTED BY ELECTRICITY, 
 
 And applied by the Electric Motor, including Electric Railway Con- 
 struction. By P. Atkinson, A.M., Ph.D. Third Edition, Fully Re- 
 vised, and New Matter added. With 94 Illustrations. 12mo, cloth. 
 
 $2.00 
 DYNAMO CONSTRUCTION. 
 
 A Practical Handbook for the Use of Engineer-Constructors and Elec- 
 tricians-in-Charge. Embracing Framework Building, Field Magnet and 
 Armature Winding and Grouping, Compounding, &c. By J. W. Urqu- 
 hart. Second Edition, Enlarged, with 114 Illustrations. 12mo, cloth. 
 
 $3.00 
 
 HOW TO MAKE A DYNAMO. 
 
 A Practical Treatise for Amateurs. Containing Illustrations and De- 
 tailed Instructions for Constructing a Small Dynamo to Produce the 
 Electric Light. By Alfred Crofts. Seventh Edition. 12mo, cloth. 
 
 .80 
 
 WIRELESS TELEGRAPHY; 
 
 Its Origins, Development, Inventions, and Apparatus. By Charles 
 Henry Sewall. With 85 Diagrams and Illustrations. 8vo, cloth. 
 
 Net $2.00 
 
30 CROSBY LOCKWOOD &» SON'S CATALOGUE. 
 SUBMARINE TELEGRAPHS; 
 
 Their History, Construction, and Working. Founded in part on Wun- 
 schendorff t s ' ' Traits de Telegraphie Sous-Marine," and Compiled from 
 Authoritative and Exclusive Sources. By Charles Bright, F.R.S.E. 
 A.M.Inst.C.E., M.I.E.E. 780 pp., fully Illustrated, including Maps and 
 Folding Plates. Royal 8vo, cloth $25.00 
 
 ELECTRICAL AND MAGNETIC CALCULATIONS. 
 
 For the Use of Electrical Engineers and Artisans, Teachers, Students, 
 and all others interested in the Theory and Application of Electricity 
 and Magnetism. By Prof. A. A. Atkinson, Ohio University. 12mo, 
 doth. . $1.50 
 
 "To teachers and those who already possess a fair knowledge of their sub- 
 ject we can recommend this book as being useful to consult when requiring 
 data or formulae which it is neither convenient nor necessary to retain by 
 memory." — The Electrician. 
 
 THE ELECTRICAL ENGINEER'S POCKET=BOOK. 
 
 Consisting of Rules, Formulae, Tables, and Data. By H. R. Kemfe, 
 M.I.E.E., A.M.Inst.C.E., Technical Officer Postal Telegraphs, Author 
 of "A Handbook of Electrical Testing." Second Edition. 32mo, 
 leather $1.75 
 
 ELECTRIC LIGHTING (ELEMENTARY PRINCIPLES OF). 
 
 By Alan A. Campbell Swinton, M.Inst.C.E., M.I.E.E. Sixth Edition. 
 With 16 Illustrations. 12mo, cloth .60 
 
 ELECTRIC LIGHT. 
 
 Its Production and Use, Embodying Plain Directions for the Treatment 
 of Dynamo-Electric Machines, Batteries, Accumulators, and Electric 
 Lamps. By J. W. Urquhart, C.E. Seventh Edition. 12mo, cloth. 
 
 $3.00 
 
 ELECTRIC LIGHT FOR COUNTRY HOUSES. 
 
 A Practical Handbook on the Erection and Running of Small Installa- 
 tions, with Particulars of the Cost of Plant and Working. By J. H. 
 Knight. Fourth Edition, Revised. 12mo, boards 50 
 
 ELECTRIC LIGHT FITTING. 
 
 A Handbook for Working Electrical Engineers, embodying Practical 
 Notes on Installation Management. By J. W. Urquhart. With 
 numerous Illustrations. Fourth Edition, Revised. 12mo, cloth. $2.00 
 
 ELECTRIC SHIP=LIGHTING. 
 
 A Handbook on the Practical Fitting and Running of Ships' Electrical 
 Plant. For the Use of Shipowners and Builders, Marine Electricians, 
 and Seagoing Engineers-in-Charge. By J. W. Urquhart, C.E. Third 
 Edition, Revised and Extended. With 88 Illustrations, 12mo, 
 cloth $3.00 
 
 DYNAMIC ELECTRICITY AND MAGNETISM. 
 
 By Philip Atkinson, A.M., Ph.D., Author of "Elements of Static 
 Electricity," &c. Crown, 8vo, 417 pp., with 120 Illustrations, cloth 
 
 $2.00 
 
 THE STUDENT'S TEXT=BOOK OF ELECTRICITY. 
 
 By H. M. Noad, F.R.S. 650 pp., with 470 Illustrations. 12mo, 
 cloth ' $4.00 
 
ARCHITECTURE, BUILDING, &>c. 31 
 
 ARCHITECTURE, BUILDING, ETC. 
 
 SPECIFICATIONS IN DETAIL. 
 
 By Frank W. Macey, Architect, Author of "Conditions of Contract." 
 Second Edition, Revised and Enlarged, containing 644 pp., and 2,000 
 
 Illustrations. Royal 8vo, cloth $8.00 
 
 Summary of Contents: — General Notes (including Points in Speci- 
 fication Writing, The Order of a Specification, and Notes on Items 
 often Omitted from a Specification). — Form of Outside Cover to a 
 Specification. — Specification of Works and List of General Condi- 
 tions. — Preliminary Items (including Shoring and House Breaker). 
 — Drainage (including Rain-water Wells and Reports). — Excavator 
 (including Concrete Floors, Roofs, Stairs, and Walls). — Pavior. — 
 Bricklayer (including Flintwork, River, and other Walling, Spring- 
 water Wells, Storage Tanks, Fountains, Filters, Terra Cotta and 
 Faience). — Mason. — Carpenter, Joiner, and Ironmonger (including 
 Fencing and Piling). — Smith and Founder (including Heating, Fire 
 Hydrants, Stable and Cow-house Fittings). — Slater (including Slate 
 Mason^i- — Tiler. — Stone Tiler. — Shingler. — Thatcher. — Plumber (in- 
 cluding Hot-water Work). — Zincworker. — Coppersmith. — Plasterer. 
 — Gasfitter. — Bellhanger. — Glazier. — Painter. — Paperhanger. — 
 General Repairs and Alterations. — Ventilation. — Road-making. — 
 Electric Light. — Index. 
 
 PRACTICAL BUILDING CONSTRUCTION. 
 
 A Handbook for Students Preparing for Examinations, and a Book 
 of Reference for Persons Engaged in Building. By John Parnell 
 Allen, Surveyor, Lecturer on Building Construction at the Durham 
 College of Science, Newcastle-on-Tyne. Fourth Edition, Revised and 
 Enlarged. Medium 8vo, 570 pp., with over 1,000 Illustrations, cloth, 
 
 $3.00 
 
 SPECIFICATIONS FOR PRACTICAL ARCHITECTURE. 
 
 A Guide to the Architect, Engineer, Surveyor, and Builder. Upon 
 the Basis of the Work by A. Bartholomew, Revised, by F. Rogers. 
 8vo, cloth. ..-. $6.00 
 
 SCIENCE OF BUILDING: 
 
 An Elementary Treatise on the Principles of Construction. By E. 
 Wyndham Tarn, M.A.Lond. Fourth Edition. 12mo, cloth. $1.40 
 
 ART OF BUILDING, 
 
 Rudiments of. General Principles of Construction , Character, Strength, 
 and Use of Materials, Preparation of Specifications and Estimates, &c. 
 By Edward Dobson, M.Inst.C.E. Fifteenth Edition, revised by J. P. 
 Allen, Lecturer on Building Construction at the Durham College of 
 Science. 12mo, cloth ,80 
 
 BOOK ON BUILDING, 
 
 Civil and Ecclesiastical. By Sir Edmund Beckett, Bart., LL.D. 
 Second Edition. 12mo, cloth $1.80 
 
 BUILDING ESTATES: 
 
 A Treatise on the Development, Sale, Purchase, and Management of 
 Building Land. By F. Maitland. Fourth Edition. 12mo, cloth, 
 
 .80 
 COTTAGE BUILDING. 
 
 By C. Bruce Allen. Twelfth Edition, with Chapter on Economic 
 Cottages for Allotments by E. E. Allen, C.E. 12mo, cloth. . .80 
 
32 CROSBY LOCKWOOD 6- SON'S CATALOGUE. 
 DWELLING=HOUSES, 
 
 Erection of, illustrated by a Perspective View, Plans, Elevations, and 
 Sections of a Pair of Villas, with the Specification, Quantities, and 
 Estimates. By S. H. Brooks. 12mo, cloth «aj qq 
 
 FARM BUILDINGS: 
 
 Their Arrangement and Construction, with Plans and Estimates. By 
 Professor J. Scott. 12mo, cloth # gQ 
 
 SHORING, 
 
 And its Application. By G. H. Blagrove. Crown 8vo, cloth. m QQ 
 
 ARCHES, PIERS, BUTTRESSES. 
 
 By William Bland. 12mo, cloth # gQ 
 
 PRACTICAL BRICKLAYING. 
 
 General Principles of Bricklaying; Arch Drawing, Cutting, and Setting; 
 Pointing; Paving, Tiling, &c. By Adam Hammond. With 68 Wood- 
 cuts. 12mo, cloth m QQ 
 
 ART OF PRACTICAL BRICK=CUTTING AND SETTING. 
 
 By Adam Hammond. With 90 Engravings. 12mo, cloth. . . . # gQ 
 
 BRICKWORK: 
 
 Embodying the General and Higher Principles of Bricklaying, Cutting, 
 and Setting; with the Application of Geometry to Roof Tiling, <fec. 
 
 By F. Walker. 12mo, cloth ^gQ 
 
 "Contains all that a student needs to learn from books. — Building News." 
 
 BRICKS AND TILES, 
 
 Rudimentary Treatise on the Manufacture of. Containing an Outline 
 of the Principles of Brickmaking. By E. Dobson, M.R.I.B.A. Addi 
 tions by C. Tomlinson, F.R.S. Illustrated. 12mo, cloth. . . -$1.20 
 
 PRACTICAL BRICK AND TILE BOOK. 
 
 Comprising: Brick and Tile Making, by E. Dobson, M.Inst.C.E. ; Prac- 
 tical Bricklaying by A. Hammond, Brick-Cutting and Setting, by A. 
 Hammond. 550 pp., with 270 Illustrations, strongly half -bound. $2.40 
 
 PRACTICAL MASONRY. 
 
 A Guide to the Art of Stone Cutting. Comprising the Construction, 
 Setting-Out, and Working of Stairs, Circular Work, Arches, Niches, 
 Domes, Pendentives, Vaults, Tracery Windows, &c; to which are 
 added Supplements relating to Masonry Estimating and Quantity Sur- 
 veying, and to Building Stones and Marbles, and a Glossary of Terms. 
 For the Use of Students, Masons, and Craftsmen. By W. R. Purchase, 
 Building Inspector to the Borough of Hove. Fifth Edition, Enlarged. 
 Royal 8vo, 226 pp., with 52 Plates, comprising over 400 Diagrams, 
 cloth $3.00 
 
 MASONRY AND STONECUTTING, 
 
 The Principles of Masonic Projection, and their Application to Con- 
 struction. By E. Dobson, M.R.I.B.A. 12mo, cloth $1.00 
 
 MODERN LIGHTNING CONDUCTORS. 
 
 An Illustrated Supplement to the Report of the Lightning Research 
 Committee of 1905, with Notes as to the Methods of Protection, and 
 Specifications. By Killingworth Hedges, M.Inst.C.E., M.I.E.E., 
 Honorary Secretary to the Lightning Research Committee, Author of 
 "American Street Railways." Medium 8vo, cloth 
 
 [Just Published Net $3.00 
 
 "The illustrations are very interesting and give one a clear idea of what 
 
 is likely to happen when a building is struck by lightning. Mr. Hedges' 
 
 suggestions of possible reasons why certain protected buildings were struck 
 
ARCHITECTURE, BUILDING, &c. 33 
 
 are instructive. He also explains the modern methods of fitting buildings 
 with lightning conductors. To the ordinary reader the book will be of in- 
 terest, and to anyone who has to design a system for protecting a building 
 from lightning strokes it will be helpful " — Builder. 
 
 PLUMBING: 
 
 A Text-Book to the Practice of the Art or Craft of the Plumber. With 
 Chapters upon House Drainage and Ventilation. By Wm. Paton 
 Buchan. Ninth Edition, with 512 Illustrations. Crown 8vo, cloth. 
 
 $1.40 
 
 HEATING BY HOT WATER, 
 
 VENTILATION AND HOT WATER SUPPLY. 
 
 By Walter Jones, M.I.M.E. 360 pages, with 140 Illustrations. 
 Medium 8vo, cloth $£.50 
 
 THE PRACTICAL PLASTERER: 
 
 A Compendium of Plain and Ornamental Plaster Work. By W. Kemp. 
 12mo, cloth # £Q 
 
 CONCRETE: ITS NATURE AND USES. 
 
 A Book for Architects, Builders, Contractors, and Clerks of Works. By 
 G E Sutcliffe, A.R.I.B.A. Second Edition, Revised and Enlarged. 
 396 pp., with Illustrations. 12mo, cloth. . . .[Just Published. $3.50 
 
 PORTLAND CEMENT FOR USERS. 
 
 By the late Henry Faija, M.Inst.C.E. Fifth Edition. Revised and 
 Enlarged by D. B. Butler, A.M.Inst.C.E. 12mo, cloth $1.20 
 
 LIMES, CEMENTS, MORTARS, CONCRETES, MASTICS, 
 PLASTERING, &c. 
 
 By G. R. Burnell, C.E. Fifteenth Edition. 12mo, cloth.. . . .60 
 
 MEASURING AND VALUING ARTIFICERS' WORK 
 
 (The Student's Guide to the Practice of). Containing Directions for 
 taking Dimensions, Abstracting the same, and bringing the Quantities 
 into Bill, with Tables of Constants for Valuation of Labour, and for the 
 Calculation of Areas and Solidities. Originally edited by E. Dobson, 
 Architect. With Additions by E. W. Tarn, M.A. Seventh Edition, 
 Revised. 12mo, cloth $3.00 
 
 QUANTITIES AND MEASUREMENTS, 
 
 In Bricklayers', Masons', Plasterers', Plumbers', Painters', Paper 
 hangers', Gilders', Smiths', Carpenters' and Joiners' Work. By A. C 
 
 Beaton, Surveyor. 12mo, cloth .60 
 
 "This book is indispensable to builders and their quantity clerks." — Eng' 
 lish Mechanic. 
 
 TECHNICAL GUIDE, MEASURER, AND ESTIMATOR. 
 
 For Builders and Surveyors. Containing Technical Directions for Meas- 
 uring Work in all the Building Trades, Complete Specifications for 
 Houses, Roads, and Drains, and an Easy Method of Estimating the 
 parts of a Building collectively. By A. C. Beaton. Tenth Edition. 
 
 Waistcoat-pocket size .60 
 
 "No builder, architect, surveyor, or valuer should be without his 
 ' Beaton.' " — Building News. 
 
 COMPLETE MEASURER; 
 
 Setting forth the Measurement of Boards, Glass, Timber, and Stone. 
 By R. Horton. Sixth Edition. 12mo, cloth $1.60 
 
 ARCHITECTURAL PERSPECTIVE. 
 
 The whole Course and Operations of the Draughtsman in Drawing a 
 Large House in Linear Perspective. Illustrated by 43 Folding Plates. 
 By F. O. Ferguson, Third Edition. 8vo, boards $1,50 
 
34 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
 PERSPECTIVE FOR BEGINNERS 
 
 For Students and Amateurs in Architecture, Painting, &c. By G. 
 Pyne. Crown 8vo, cloth # g0 
 
 PRACTICAL RULES ON DRAWING. 
 
 For the Builder and Young Student in Architecture. By G. Pyne. 4to 
 
 $3.00 
 THE MECHANICS OF ARCHITECTURE. 
 
 A Treatise on Applied Mechanics, especially Adapted to the Use of 
 Architects. By E. W. Tarn, M.A., Author of "The Science of Build- 
 ing," &c. Second Edition, Enlarged. Illustrated with 125 Diagrams. 
 
 12mo, cloth $3.00 
 
 ' ' The book is a very useful and helpful manual of architectural mechan- 
 ics." — Builder. 
 
 A HANDY BOOK OF VILLA ARCHITECTURE. 
 
 Being a Series of Designs for Villa Residences in various Styles. With 
 Outline Specifications and Estimates. By C. Wickes, Architect, Au- 
 thor of "The Spires and Towers of England," &c. 61 Plates, 4to, half- 
 morocco, gilt edges $12.00 
 
 DECORATIVE PART OF CIVIL ARCHITECTURE. 
 
 By Sir William Chambers, F.R.S. With Portrait, Illustrations, Notes, 
 and an Examination of Grecian Architecture, by Joseph Gwilt, 
 F.S.A. Revised and Edited by W. H. Leeds. 66 Plates, 4to, cloth. 
 
 $8.40 
 
 HINTS TO YOUNG ARCHITECTS. 
 
 By George Wightwick, Architect, Author of "The Palace of Archi- 
 tecture," &c, &c. Sixth Edition, revised and enlarged by G. Huskis- 
 bon Guillaume, Architect. 12mo, cloth $1.40 
 
 THE ARCHITECTS' GUIDE. 
 
 Being a Text-book of Useful Information for Architects, Engineers, Sur- 
 veyors, Contractors, Clerks of Works, &c. By F. Rogers. 12mo, 
 
 $1.40 
 ARCHITECTURE— ORDERS. 
 
 The Orders and their ^Esthetic Principles. By W. H. Leeds. 12mo. 
 
 .60 
 ARCHITECTURE— STYLES. 
 
 The History and Description of the Styles of Architecture of Various 
 Countries, from the Earliest to the Present Period. By T. Talbot 
 Bury, F.R.I.B.A., &c. Illustrated. 12mo, cloth # g() 
 
 "Orders and Styles of Architecture," in One Vol $1.40 
 
 ARCHITECTURE— DESIGN. 
 
 The Principles of Design in Architecture, as deducible from Nature and 
 exemplified in the Works of the Greek and Gothic Architects. By Edw. 
 L. Garbett, Architect. 12mo, cloth $1.00 
 
 "We know no work that we would sooner recommend to an attentive 
 reader desirous to obtain clear views of the nature of architectural art. The 
 book is a valuable one." — Builder. 
 
 *#* The three preceding Works in One handsome Vol., half-bound, entitled 
 "Modern Architecture," price $2.40 
 
 ARCHITECTURAL MODELLING IN PAPER, 
 
 The Art of. By T. A. Richardson. 12mo, cloth # g() 
 
SANITATION AND WATER SUPPLY. 35 
 
 YITRUYIUS— THE ARCHITECTURE OF MARCUS 
 
 V1TRUVIUS POLLIO. 
 
 In Ten Books. Translated from the Latin by J. Gwilt. With 23 
 Plates. 12mo, cloth $2.00 
 
 N.B. — This is the[only Edition of Vitrtjvius procurable at a moderate price. 
 
 GRECIAN ARCHITECTURE, 
 
 An Inquiry into the Principles of Beauty in ; with an Historical View 
 of the Rise and Progress of the Art in Greece. By the Earl of Aber- 
 deen # 4Q 
 
 *#* The two preceding Works in One handsome Volume, half-bound, entitled 
 "Ancient Architecture," price $2.40 
 
 ACOUSTICS OF PUBLIC BUILDINGS: 
 
 The Laws of Sound as applied to the Arrangement of Buildings. By 
 Professor T. Rogers Smith, F.R.I.B.A. New Edition, revised. With 
 numerous Illustrations. 12mo, cloth m QQ 
 
 LIGHT:' 
 
 An Introduction to the Science of Optics. Designed for the Use of 
 Stilaents of Architecture, Engineering, and other Applied Sciences. By 
 E. W. Tarn, M.A. 12mo, cloth # 60 
 
 SANITATION AND WATER SUPPLY. 
 
 THE HEALTH OFFICER'S POCKET=BOOK. 
 
 A Guide to Sanitary Practice and Law. For Medical Officers of Health, 
 Sanitary Inspectors, Members of Sanitary Authorities, &c. By Edward 
 F. Willoughby, M.D. (Lond.), &c. Second Edition, Revised and En- 
 larged. Fcap. 8vo, leather $4.00 
 
 THE WATER SUPPLY OF TOWNS AND THE CON- 
 
 STRUCTION OF WATER-WORKS. 
 
 By Professor W. K. Burton, A.M. Inst. C.E. Second Edition, Re- 
 vised and Extended. Royal 8vo, cloth. (See page 12.) $9.00 
 
 THE WATER SUPPLY OF CITIES AND TOWNS. 
 
 By William Humber, A.M.Inst. C.E., and M.Inst.M.E. Imp. 4to, half- 
 bound morocco. (See page 12.) $45.00 
 
 WATER AND ITS PURIFICATION. 
 
 A Handbook for the Use of Local Authorities, Sanitary Officers, and 
 others interested in Water Supply. By S. Rideal, D.Sc. Lond., F.I.C. 
 Second Edition, Revised, with Additions, including numerous Illustra- 
 tions and Tables. 12mo, cloth $3.00 
 
 RURAL WATER SUPPLY. 
 
 A Practical Handbook on the Supply of Water and Construction of 
 Water-works for Small Country Districts. By Allan Greenwell, 
 A.M.I. C.E. , and W. T. Curry, A.M.I.C.E. Revised Edition. 12mo, 
 doth $2.00 
 
 WATER ENGINEERING. 
 
 A Practical Treatise on the Measurement, Storage, Conveyance, ana 
 Utilisation of Water for the Supply of Towns. By C. Slagg, A.M. 
 Inst.CE $3.00 
 
36 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 THE PURIFICATION OF SEWAGE. 
 
 Being a Brief Account of the Scientific Principles of Sewage Purifica- 
 tion, and their Practical Application. By Sidney Barwise, M.D 
 (Lond.), B.Sc, M.R.C.S., D.P.H. (Camb.), Fellow of the Sanitary In- 
 stitute, Medical Officer of Health to the Derbyshire County Council. 
 Second Edition, Revised and Enlarged, with an Appendix on the Analy- 
 sis of Sewage and Sewage Effluents. With numerous Illustrations and 
 
 Diagrams. Demy 8vo, cloth Net $3.50 
 
 Summary of Contents: — Sewage: Its Nature and Composition. — 
 The Chemistry or Sewage. — Varieties of Sewage and the Changes it 
 Undergoes. — River Pollution and its Effects. — The Land Treatment 
 of Sewage. — Precipitation, Precipitants, and Tanks. — The Liquefac- 
 tion of Sewage. — Principles involved in the Oxidation of Sewage. — 
 Artificial Processes of Purification. — Automatic Distributors and 
 Special Filters. — Particulars of Sewerage and Sewage Disposal 
 Schemes required by Local Government Board. — Useful Data.— Ap- 
 pendix: The Apparatus required for Sewage Analysis. — Standard 
 Solutions used in the Method of Sewage Analysis. — Tables: Esti- 
 mation of Ammonia. — Nitrogen as Nitrates. — Incubator Test, Oxygen 
 Absorbed. — To Convert Grains per Gallon to Parts per 100,000. 
 
 SANITARY WORK IN SMALL TOWNS AND VILLAGES. 
 
 By Charles Slagg, A.M. Inst. C.E. Third Edition, Enlarged. 12mo 
 doth $3.00 
 
 VENTILATION: 
 
 A Text-Book to the Practice of the Art of Ventilating Buildings. By 
 W. P. Buchan. With 170 Illustrations. 12mo, cloth $1.40 
 
 CARPENTRY, TIMBER, ETC. 
 
 PRACTICAL FORESTRY. 
 
 And its Bearing on the Improvement of Estates. By Charles E. 
 Curtis, F.S.I., Professor of Forestry, Field Engineering, and General 
 Estate Management, at the College of Agriculture, Downton. Second 
 
 Edition, Revised. 12mo, cloth .$1,40 
 
 Prefatory Remarks. — Objects of Planting. — Choice of a Forester. 
 — Choice of Soil and Site. — Laying Out of Land for Plantations. — 
 Preparation of the Ground for Planting. — Drainage. — Planting. — 
 Distances and Distribution of Trees in Plantations. — Trees and 
 Ground Game. — Attention after Planting. — Thinning of Plantations. 
 — Pruning of Forest Trees. — Realization. — Methods of Sale.— 
 Measurement of Timber. — Measurement and Valuation of Larch's 
 Plantation. — Fire Lines. — Cost of Planting. 
 
 WOODWORKING MACHINERY. 
 
 Its Rise, Progress, and Construction. With Hints on the Management 
 of Saw Mills and the Economical Conversion of Timber. Illustrated 
 with Examples of Recent Designs by leading English, French, and 
 American Engineers. By M. Powis Bale, M.Inst. C.E. , M.I.Mech.E. 
 Second Edition, Revised, with large Additions. 8vo, 440 pp., cloth, 
 
 $3.50 
 
 SAW MILLS. 
 
 Their Arrangement and Management, and the Economical Conversion 
 of Timber. By M. Powis Bale, M.Inst.C.E., M.I.Mech.E. Second 
 Edition, Revised. 12mo, cloth $4.00 
 
CARPENTRY, TIMBER, 6»c. 37 
 
 THE ELEMENTARY PRINCIPLES OF CARPENTRY. 
 
 A Treatise on the Pressure and Equilibrium of Timber Framing, the 
 Resistance of Timber, and the Construction of Floors, Arches, Bridges, 
 Roofs, Uniting Iron and Stone with Timber, &c. To which is added 
 an Essay on the Nature and Properties of Timber, &c, with Descrip- 
 tions of the kinds of Wood used in Building; also numerous Tables 
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38 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
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 SCHOOL OF PAINTING FOR THE IMITATION OF 
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DECORATIVE ARTS, &c. 39 
 
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 MODERN ALPHABETS, PLAIN AND ORNAMENTAL. 
 
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 MEDI/EVAL ALPHABETS AND INITIALS. 
 
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 A PRIMER OF THE ART OF ILLUMINATION. 
 
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 GRAMMAR OF COLOURING. 
 
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 HOUSE PAINTING, GRAINING, MARBLING, AND 
 
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 ART OF LETTER PAINTING MADE EASY. 
 
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40 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 PAINTING POPULARLY EXPLAINED. 
 
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 WOOD=CARVING FOR AMATEURS. 
 
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 NATURAL SCIENCE, ETC. 
 
 THE VISIBLE UNIVERSE. 
 
 Chapters on the Origin and Construction of the Heavens. By J. E. 
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 MANUAL OF THE MOLLUSCA : 
 
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 HANDBOOK OF MECHANICS. 
 
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CHEMICAL MANUFACTURES, CHEMISTRY, &c. 41 
 
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 NATURAL PHILOSOPHY FOR SCHOOLS.. ..$1.40 
 
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 THE ELECTRIC TELEGRAPH. 
 
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 CHEMICAL MANUFACTURES, 
 CHEMISTRY, ETC. 
 
 THE OIL FIELDS OF RUSSIA AND THE RUSSIAN 
 PETROLEUM INDUSTRY. 
 
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 THE ANALYSIS OF OILS AND ALLIED SUBSTANCES. 
 
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 A HANDYBOOK FOR BREWERS. 
 
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 A P0CKET=B00K OF MENSURATION AND GAUGING. 
 
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 Second Edition, Revised. 18mo, leather $1.60 
 
42 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
 THE GAS ENGINEER'S POCKET=BOOK. 
 
 Comprising Tables, Notes and Memoranda relating to the Manufacture. 
 Distribution and Use of Coal Gas and the Construction of Gas Works. 
 By H. O'Connor, A.M. Inst.C.E. Second Edition, Revised. 470 pp., 
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 LIGHTING BY ACETYLENE 
 
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 ENGINEERING CHEMISTRY. 
 
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 NITRO=EXPLOSIVES. 
 
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 A HANDBOOK OF MODERN EXPLOSIVES. 
 
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 DANGEROUS GOODS. 
 
 Their Sources and Properties, Modes of Storage and Transport. With 
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 A MANUAL OF THE ALKALI TRADE. 
 
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 THE BLOWPIPE IN CHEMISTRY, MINERALOGY, Etc. 
 
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 cloth $3.00 
 
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INDUSTRIAL AND USEFUL ARTS. 43 
 
 THE ARTISTS' MANUAL OF PIGMENTS. 
 
 Showing their Composition, Conditions of Permanency, Non-Per- 
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 Standage. Third Edition. 12mo, cloth $1.00 
 
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 INDUSTRIAL ARTS, TRADES, AND 
 MANUFACTURES. 
 
 THE CULTIVATION AND PREPARATION OF PARA 
 
 RUBBER. 
 
 By W. H. Johnson, F.L.S., F.R.H.S., Director of Agriculture, Gold 
 Coast Colony, West Africa, Commissioned by Government in 1902 to 
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 PRACTICAL PAPER=MAKINQ. 
 
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44 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 THE ART OF SOAP=MAKING. 
 
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 Sixth Edition, including an Appendix on Modern Candlemaking. 
 
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 THE ART OF LEATHER MANUFACTURE. 
 
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 MODERN HOROLOGY, IN THEORY AND PRACTICE. 
 
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INDUSTRIAL AND USEFUL ARTS. 45 
 
 CLOCKS, WATCHES, & BELLS for PUBLIC PURPOSES. 
 
 A Rudimentary Treatise. By Edmund Beckett, Lord Grimthorpe, 
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 HISTORY OF WATCHES & OTHER TIMEKEEPERS. 
 
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 HALL=MARKING OF JEWELLERY. 
 
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 MECHANICAL DENTISTRY: 
 
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 BRASS FOUNDER'S MANUAL: 
 
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 By W. Graham. 12mo, cloth ,80 
 
46 CROSBY LOCKWOOD &> SON'S CATALOGUE 
 SHEET METAL WORKER'S INSTRUCTOR. 
 
 Comprising a Selection of Geometrical Problems and Practical Rules 
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 Copper, and Tin-Plate Workers. By Reuben Henry Warn. Piactical 
 Tin-Plate Worker. New Edition, Revised and greatly Enlarged by 
 Joseph G. Horner, A.M.I.M.E. 12mo, 254 pp.. with 430 Illustra- 
 tions, cloth S3. 00 
 
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 A Practical Handbook for Tinsmiths, Coppersmiths, Zincworkers, &c , 
 with 46 Diagrams and Working Patterns. By W. J, E. Crane. Fourth 
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 GAS FITTING: 
 
 A Practical Handbook. By John Black. Revised Edition With 
 130 Illustrations. 12mo, cloth $1.00 
 
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 TEA MACHINERY AND TEA FACTORIES. 
 
 A Descriptive Treatise on the Mechanical Appliances required in the 
 Cultivation of the Tea Plant and the Preparation of Tea for the Market. 
 By A. J. Wallis-Tayler, A.M.Inst.C.E. Medium 8vo, 468 pp. With 
 218 Illustrations $10.00 
 
 Summary op Contents. 
 
 Mechanical Cultivation or Tillage or the Soil. — Plucking or 
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 FLOUR MANUFACTURE. 
 
 A Treatise on Milling Science and Practice, By Friedrich Kick, 
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 PASTRYCOOK & CONFECTIONER'S GUIDE. 
 
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INDUSTRIAL AND USEFUL ARTS. 47 
 
 MODERN FLOUR CONFECTIONER. 
 
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48 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 HANDYBOOKS FOR HANDICRAFTS. 
 
 BY PAUL N. HASLUCK, 
 
 Author of "Lathe Work," &c. 12mo, 144 pp., price 50c. each. 
 t5P** These Handybooks have been written to supply information for Work- 
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 METAL TURNER'S HANDYBOOK. 
 
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 WOOD TURNER'S HANDYBOOK. 
 
 A Practical Manual for Workers at the Lathe. With over 100 Illus- 
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 WATCH JOBBER'S HANDYBOOK. 
 
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 upwards of 100 Illustrations .50 
 
 PATTERN MAKER'S HANDYBOOK. 
 
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 MECHANIC'S WORKSHOP HANDYBOOK. 
 
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 MODEL ENGINEER'S HANDYBOOK. 
 
 A Practical Manual on the Construction of Model Steam Engines. 
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 CLOCK JOBBER'S HANDYBOOK. 
 
 A Practical Manual on Cleaning, Repairing, and Adjusting. With 
 upwards of 100 Illustrations .50 
 
 CABINET WORKER'S HANDYBOOK. 
 
 A Practical Manual on the Tools, Materials, Appliances, and Processes 
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 WOODWORKER'S HANDYBOOK. 
 
 Embracing Information on the Tools, Materials, Appliances, and 
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COMMERCE, COUNTING-HOUSE WORK, &c. 49 
 
 COMMERCE, COUNTING-HOUSE WORK, 
 TABLES, ETC. 
 
 LESSONS IN COMMERCE. 
 
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 THE BOREIQN COMMERCIAL CORRESPONDENT. 
 
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 FACTORY ACCOUNTS: their PRINCIPLES & PRACTICE. 
 
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 MODERN METROLOGY. 
 
 A Manual of the Metrical Units and Systems of the present Century. 
 With an Appendix containing a proposed English System. By 
 Lowis d'A. Jackson, A.M. Inst. C.E., Author of "Aid to Survey Prac- 
 tice," &c. 8vo, cloth $5.00 
 
 SERIES OF METRIC TABLES. 
 
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 By C. H. Dowling, C.E. 8vo, cloth $4.00 
 
 IRON=PLATE WEIGHT TABLES. 
 
 For Iron Shipbuilders, Engineers, and Iron Merchants Contpining the 
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 By H. Burlinson and W. H. Simpson. 4to, half-bound $10.00 
 
5o CROSBY LOCKWOOD &> SON'S CATALOGUE. 
 
 AGRICULTURE, FARMING, 
 GARDENING, ETC. 
 
 THE COMPLETE GRAZIER AND FARMER'S AND 
 CATTLE BREEDER'S ASSISTANT. 
 
 A Compendium of Husbandry.. Originally Written by William 
 Youatt. Fourteenth Edition, entirely Re-written, considerably En- 
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 Author of "The Elements of Agriculture," &c. Royal, 8vo, 1,100 pp., 
 450 Illustrations, handsomely bound $1#.00 
 
 STOCK: CATTLE, SHEEP, AND HORSES. 
 
 Vol. III.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
 Woodcuts. 12mo, cloth $1.00 
 
 SHEEP: 
 
 The History, Structure, Economy, and Diseases of. By W. C. Spooner. 
 Fifth Edition, with Engravings, including Specimens of New and 
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 MEAT PRODUCTION: 
 
 A Manual for Producers, Distributors, and Consumers of Butchers' 
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 MILK, CHEESE, AND BUTTER. 
 
 A Practical Handbook on their Properties and the Processes of their 
 Production. Including a Chapter on Cream and the Methods of its 
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 tions. 12mo, cloth $3.00 
 
 BRITISH DAIRYING. 
 
 A Handy Volume on the Work of the Dairy-Farm. For the Use of 
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 DAIRY, PIGS, AND POULTRY. 
 
 Vol. IV. OUTLINES OF MODERN FARMING. By R. Scott 
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 THE ELEMENTS OF AGRICULTURAL GEOLOGY. 
 
 A Scientific Aid to Practical Farming. By Primrose McConnell. 
 Author of "Note-book of Agricultural Facts and Figures." 8vo, cloth, 
 
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 SOILS, MANURES, AND CROPS. 
 
 Vol. I.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
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 FERTILISERS AND FEEDING STUFFS. 
 
 Their Properties and Uses. A Handbook for the Practical Farmer. 
 By Bernard Dyer, D.Sc (Lond.) With the Text of the Fertilisers 
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 THE ROTHAMSTED EXPERIMENTS AND THEIR 
 
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AGRICULTURE, FARMING, GARDENING, &c. 51 
 SYSTEMATIC SMALL FARMING. 
 
 Or, The Lessons of My Farm. Being an Introduction to Modern Farm 
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 of Modern Farming," &c. 12mo, cloth $2.40 
 
 THE FIELDS OF GREAT BRITAIN. 
 
 A Text-Book of Agriculture. Adapted to the Syllabus of the Science 
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 Hugh Clements (Board of Trade). Second Edition, Revised, with 
 Additions. 18mo, cloth $1.00 
 
 OUTLINES OF MODERN FARMING. 
 
 By R. Scott Burn. Soils, Manures, and Crops — Farming and Farming 
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 FARM ENGINEERING, The COMPLETE TEXT=BOOK of. 
 
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 DRAINING AND EMBANKING. 
 
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 IRRIGATION AND WATER SUPPLY: 
 
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 Professor J. Scott. 12mo, cloth .60 
 
 FARM ROADS, FENCES, AND GATES: 
 
 A Practical Treatise 'on the Roads, Tramways, and Waterways of the 
 Farm; the Principles of Enclosures; and on Fences, Gates, and Stiles. 
 By Professor John Scott. 12mo, cloth ,60 
 
 BARN IMPLEMENTS AND MACHINES: 
 
 Treating of the Application of Power to the Operations of Agriculture 
 and of the various Machines used in the Threshing-barn, in the Stock- 
 yard, Dairy, &c. By Professor John Scott. With 123 Illustrations. 
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 OUTLINES OF FARM MANAGEMENT. 
 
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 OUTLINES OF LANDED ESTATES MANAGEMENT. 
 
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 of Farms, &c; Roads, Fences, Gates, Irrigation, Drainage, &c. By 
 R. S. Burn. 13mo, cloth $1.00 
 
52 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 FARMING AND FARMING ECONOMY. 
 
 Historical and Practical. Vol. II.— OUTLINES OF MODERN 
 FARMING. By R. Scott Burn. 12mo, cloth $1.20 
 
 UTILIZATION OF SEWAGE, IRRIGATION, &c. 
 
 Vol. V.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
 Woodcuts. 12mo, cloth $1.00 
 
 N0TE=B00K OF AGRICULTURAL FACTS & FIGURES 
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 By Primrose McConnell, B.Sc, Fellow of the Highland and Agri- 
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 leather, gilt edges [Just Published. $3.0<l> 
 
 TABLES and MEMORANDA for FARMERS, GRAZIERS, 
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 With a New System of Farm Book-keeping. By Sidney Francis. 
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 READY RECKONER FOR ADMEASUREMENT OF LAND. 
 
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 A PLAIN GUIDE TO GOOD GARDENING; 
 
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 COTTAGE GARDENING; 
 
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AGRICULTURE, FARMING, GARDENINR, &c. 53 
 THE LADIES' MULTUM=IN=PARVO FLOWER GARDEN. 
 
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 ART OF GRAFTING AND BUDDING. 
 
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 By W. H. Johnson, F.L.S., F.R.H.S. 8vo, cloth Net $3.00 
 
 For Summary of Contents, see page 43. 
 
 BEES FOR PLEASURE AND PROFIT. 
 
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54 CROSBY LOCKWOOD 6» SON'S CATALOGUE. 
 EUCLID, 
 
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MATHEMATICS, ARITHMETIC, &c. 55 
 
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56 CROSBY LOCKWOOD &■ SON'S CATALOGUE. 
 LAW AND MISCELLANEOUS. 
 
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INDEX OF SUBJECTS. 
 
 Acetylene Gas, Gibbs, 42 
 
 Acoustics, Smith, 35 
 
 Aerial Navigation, Walker, 11 
 
 Tramways, Tayler, 2 
 
 Agricultural Geology, McCon- 
 nell, 50 
 
 Note Book, McConnell, 52 
 
 Surveying, Scott, 5 1 
 
 Air Machinery, Weisbach, 9, 22 
 Algebra, H addon, 54 
 Alkali Trade, Lomas, 42 
 Alphabets, Delamotte, 39 
 Alternating Current Machines, 
 
 Sheldon and Mason, 29 
 Animal Physics, Lardner, 56 
 
 Physiology, Lardner, 41 
 
 Arches, Piers, &c, Bland, 32 
 Architect's Guide, Rogers, 34 
 Architectural Modelling, Rich- 
 ardson, 34 
 Architecture, Ancient, 34 
 
 Civil, Chambers, 34 
 
 Design, Garbett, 34 
 
 Grecian, Aberdeen, 35 
 
 Mechanics of, Tarn, 34 
 
 Modern, 34 
 
 of Vitruvius, Gwilt, 35 
 
 Orders, Leeds, 34 
 
 Orders and Styles, 34 
 
 Styles, Bury, 34 
 
 Arithmetic, H addon, 54 
 
 Young, 54 
 
 Equational, Hipsley, 54 
 
 Armature, Windings, Arnold, 29 
 Artists' Pigments, Standage, 43 
 Asbestos, Jones, 27 
 Astronomical Glossary, Gore, 40 
 Astronomy, Lardner, 41 
 Main and Lynn, 40 
 
 Barn Implements, Scott, 51 
 
 Beams, Flexure of, Guy, 18 
 
 Bees, Samson, 53 
 
 Blasting, Burgoyne, 19 
 
 Blowpipe, i?<m, 42 
 
 Boiler and Factory Chimneys, 
 
 Wilson, 4 
 Boilers, Armstrong, 5 
 
 Bauer, 20 
 
 Courtney, 3 
 
 Foley, 3 
 
 Horner, 4 
 
 Hutton, 3 
 
 -j Wilson, 4 
 
 Book-keeping, H addon, 54 
 Boot and Shoe Making, Zerao, 44 
 Brass Founding, Graham, 45 
 Bread and Biscuit Baker, Wells, 
 46 
 Breakfast Dishes, Allen, 47 
 Brewing and Malting, Wright, 
 
 4i 
 Brick and Tile Book, 33 
 
 Making, Dobson, 32 
 
 Brick-cutting, Hammond, 32 
 Bricklaying, Hammond, 32 
 
 57 
 
5» 
 
 INDEX TO CATALOGUE. 
 
 Brickwork, Walker, 32 
 Bridges, Iron, Humber, 16 
 
 Iron, Pendred, 16 
 
 Oblique, Buck, 16 
 
 Tubular, Dempsey, 17 
 
 Bridges and Viaducts, Campin, 
 
 17 
 British Mining, Hunt, 25 
 Builders' Measuring, Beaton, 33 
 
 Quantities, Beaton, 33 
 
 Building, a Book on, Beckett, 31 
 
 Art of, Dobson, 31 
 
 Construction, Allen, 31 
 
 Cottage, Allen, 31 
 
 Dwelling Houses, Brooks, 
 
 3 2 
 
 Estates, Maitland, 31 
 
 Farm, Scott, 32 
 
 Science of, Tarn, 31 
 
 Cabinet-Making, Bitmead, 37 
 
 Working, Hasluck, 48 
 
 Calculator, O'Gorman, 56 
 Calculus, Differential, Woolhouse, 
 
 55 
 
 Integral, Cox, 55 
 
 Carpenter's Guide, Nicholson, 
 
 37 
 Carpentry and Joinery, Tredgold 
 and Tarn, 37 
 
 Tredgold, 37 
 
 Cattle, Sheep, &c, Burn, 50 
 Cements, &c, Standage, 47 
 Chain Cables, Traill, 20 
 Chemistry of Mining, Byrom, 26 
 Chimneys, Wilson, 4 
 Circular Work, Collings, 37 
 Civil Engineering, Law, 18 
 Clock Jobbing, Hasluck, 48 
 Clocks, Watches, and Bells, 
 
 Beckett, 45 
 Coach-Building, Burgess, 47 
 Coal & Iron Industries, Meade, 
 
 26 
 
 Mining, Cockin, 26 
 
 Smyth, 26 
 
 Colliery Manager, Pamely, 25 
 
 ■ Working, Bulman and Red- 
 
 mayne, 26 
 
 Colouring, .FVe/i &" Davidson, 
 
 39 
 Colours & Dye Wares, Slater, 
 
 42 
 Commerce, Gambaro, 49 
 Commercial Correspondence, 
 
 Baker, 49 
 Compound Interest, Thoman, 
 
 54 
 Concrete, Sutcliffe, 33 
 Confectioner, Flour, Wells, 47 
 Confectionery, Wells, 46 
 Constructional Ironwork, 
 
 Campin, 17 
 Copper, Metallurgy of, Eissler, 
 
 24 
 Cottage Building, Allen, 31 
 
 Gardening, Hobday, 52 
 
 Cotton Manufacture, Lister, 
 
 44 
 Cranes, Glynn, 11 
 Creation, Records of, Le Fa«#, 
 
 40 
 Curves, Tables of, Beazeley, 15 
 Cyanide Process, Eissler, 23 
 
 Dairying, British, Sheldon, 50 
 Dairy, Pigs, and Poultry, -Bwrw, 
 
 5° 
 Dangerous Goods, Phillips, 42 
 Decoration, Facey, 38 
 House-Painting, Graining, 
 
 &c, 38 
 Imitation of Woods and 
 
 Marbles, 38 
 
 Marble, Blagrove, 39 
 
 Decorator's Assistant, 39 
 
 Deep Level Mines of the Rand, 
 
 Denny, 22 
 Diamond Drilling, Denny, 23 
 Dictionary of Architecture, 
 
 Weale and Hunt, 56 
 
 Painters, Daryl, 56 
 
 Direct Current Machines, Sheldon 
 
 and Mason, 29 
 Drainage of Lands, Clark, 14 
 
 (Mine), Michell, 25 
 
 Draining & Embanking, Scott, 
 5i 
 
INDEX TO CATALOGUE. 
 
 59 
 
 Drawing Instruments, Heather, 
 55 
 
 Rules on, Pyne, 34 
 
 Dwelling Houses, Brooks, 32 
 
 Dynamic Electricity, Atkinson, 
 
 3° 
 
 Dynamo Construction, Urquhart, 
 
 29 
 
 How to Make, Crofts, 29 
 
 Motor and Switchboard 
 
 Circuits, Bowker, 29 
 
 Earthwork, Graham, 16 
 Tables, Broadbent &• Cam- 
 pin, 16 
 
 Tables, Buck, 16 
 
 Earthy Minerals, Davies, 24 
 Electrical Calculations, Atkinson, 
 
 3° 
 
 ■ Conductors, Perrine, 29 
 
 Engineering, Alexander, 28 
 
 Sewell, 28 
 
 — — Pocket Book, Kempe, 30 
 
 Transmission, Abbott, 28 
 
 Electricity Applied to Mining, 
 Lupton, Parr, &> Perkin, 25, 28 
 
 Lardner and Foster, 41 
 
 Text-Book, Noad, 30 
 
 Electric Light Fitting, Urquhart, 
 
 3° 
 
 Light, Knight, 30 
 
 Light, Urquhart, 30 
 
 Lighting, Swinton, 30 
 
 Ship-Lighting, Urquhart, 30 
 
 ': Telegraph, Lardner, 41 
 
 Electro-Metallurgy, Watt, 45 
 
 ■ Plating, Urquhart, 45 
 
 Plating, Watt and Philip, 
 
 45 
 
 Typing, Urquhart, 45 
 
 Embroiderer's Design, Delamotte, 
 
 39 
 Engine-Driving Life, Reynolds, 
 
 6 
 Engineering Chemistry, Phillips, 
 
 42 
 
 Drawing, Maxton, 8 
 
 Estimates, 9 
 
 Engineering Tools, Horner, 2 
 
 Engineer's Assistant, Templeton, 
 
 8 
 
 Companion, Edwards, 8 
 
 Field Book, Haskoll, 15 
 
 Handbook, Hutton, 5 
 
 Pocket-Book, C/ar&, 7 
 
 Reference Book, Foley, 3 
 
 Turning, Horner, 2 
 
 Year Book, Kempe, 7 
 
 Engineman's Companion, Reyn- 
 olds, 7 
 Euclid, Law, 54 
 Excavating, Prelim, 16 
 Explosives, Eissler, 42 
 Nitro, Sanjord, 42 
 
 Factory Accounts, Garcke &■ 
 
 Fells, 49 
 Farm Buildings, ScoM, 32 
 
 Engineering, Scott, 5 1 
 
 Management, Burn, 5 1 
 
 Roads, &c, Scott, 51 
 
 Farmer's Tables, Francis, 52 
 Farming Economy, Bum, 52 
 
 Outlines, Burn, 51 
 
 Small, Burn, 5 1 
 
 Fertilisers, &c, Dyer, 50 
 Field Fortification, Knollys, 56 
 
 Implements, ScoW, 5 1 
 
 Fields of Gt. Britain, Clements, 
 5 1 
 Fires & Fire Engines, Young, n 
 Flour, Kick and Powles, 46 
 Forestry, Curtis, 36 
 Foundations, &c, Dobson, 19 
 French Polishing, Bitmead, 47 
 Fruit Trees, Du Breuil, 53 
 Fuel, Williams and Clark, 10 
 Fuels, Phillips, 10 
 
 Garden, Forcing, Wood, 52 
 
 Receipts, Quin, 52 
 
 Gardening, Good, Wood, 52 
 
 Ladies', Wood, 53 
 
 Multum-in-Parvo, Wood, 
 
 5 2 
 Gas and Oil Engines, Bale, J 
 Engines, Goodeve, 7 
 
6o 
 
 INDEX TO CATALOGUE. 
 
 Gas Engineer's Pocket Book, 
 
 O'Connor, 42 
 
 Fitting, Black, 47 
 
 Producer Plants, Mathot, 
 
 6 
 
 Works, Hughes, 18 
 
 Geology, Historical, Tate, 27 
 
 Physical, Tate, 27 
 
 Tate, 27 
 
 Geometry, Tarn, 17 
 
 Analytical, Hann, 55 
 
 Descriptive, Heather, 54 
 
 Technical, Sprague, 17 
 
 ■ of Compasses, Byrne, 17 
 
 Plane, Heather, 54 
 
 Girders (Iron), Buck, 17 
 
 Glass Staining, Gessert and 
 
 Fromberg, 40 
 Gold Assaying, Phillips, 23 
 
 and Silver, Merritt, 23 
 
 Metallurgy of, Eissler, 23 
 
 Prospecting, Rankin, 23 
 
 Goldsmith's Handbook, Gee, 45 
 
 and Silversmith, Gee, 46 
 
 Grafting and Budding, Baltet, 
 
 53 
 Granites, Harris, 27 
 Grazier, Complete, Fream, 50 
 
 Hall Marking Jewellery, Gee, 
 
 45 
 Handrailing, Collin gs, 37 
 
 Goldthorp, 37 
 
 Hay & Straw Measurer, Steele, 
 
 5 2 
 Health Officer, Willoughby, 35 
 Heat (Expansion by), Keily, 18 
 Heat, Lardner and Loewy, 41 
 Heating by Hot Water, Jones, 
 
 33 
 Hints to Architects, Wightwick 
 
 andGuillaume, 34 
 Hoisting Machinery, Horner, 2 
 Hoisting & Conveying Ma- 
 chinery, Zimmer, 2 
 Horology, Saunter, 44 
 Horticulture, N ewsham, 52 
 House Decoration, Facey, 38 
 Painting, Davidson, 39 
 
 Hydraulic Manual, Jackson, 13 
 
 Engineering, Marks, 13 
 
 Tables, Neville, 13 
 
 Hydrostatics, Lardner, 41 
 
 Illumination, Delamotte, 39 
 India Rubber, Johnson, 43, 53 
 Inflammable Gas, Clowes, 26 
 Iron and Steel, Hoare, 8 
 Iron, Metallurgy of, Bauerman, 
 
 25 
 
 Ores, Kendall, 25 
 
 Plate Weight Tables, 
 
 Burlinson and Simpson, 49 
 Irrigation, Mawson, 11 
 and Water Supply, 5coW, 
 
 5 1 
 
 Jeweller's Assistant, Gee, 45 
 Joints (Builders'), Christy, 37 
 
 Key to Haddon's Algebra, 54 
 — — to Young's Arithmetic, 54 
 Kitchen Gardening, Glenny, 52 
 
 Land, Ready Reckoner, Arman, 
 
 5 2 
 
 (Reclamation of), Beaze- 
 
 ley, 12 
 Landed Estates, Burn, 51 
 Lathe Work, Hasluck, 9 
 Laundry, Management, 47 
 Lead (Argentiferous), Eissler, 
 
 24 
 Leather Manufacture, Watt, 44 
 Letter Painting, Badenoch, 39 
 Levelling, Simms, 15 
 Light, Tarn, 35 
 Light Railways, Calthrop, n 
 Lightning Conductors, Hedges, 
 
 32 
 Limes, Cements, Burnett, 33 
 Locks, Tomlinson, 47 
 Locomotive Engine, Stretton, 6 
 
 Engine, W eatherburn, 6 
 
 Engine Driving, Reynolds, 6 
 
 Engineer, Reynolds, 6 
 
 Engines, Dempsey, 6 
 
INDEX TO CATALOGUE. 
 
 61 
 
 Logarithms, Law, 53 
 
 Machine Shop Tools, 2 
 Machinery, Details, Campin, 9 
 Marble Decoration, Blagrove, 
 
 39 
 
 Marine Engineering, Brewer, 
 
 20 
 
 Engineer, Wannan, 20 
 
 Engineer's Pocket Book, 
 
 Wannan, 20 
 Marine Engines & Boilers, 
 Bauer, Donkin and Robertson, 
 
 19 
 
 Engines, Murray, 20 
 
 Market Gardening, Shaw, 52 
 Masonry, Purchase, 32 
 and Stone-Cutting, Dob- 
 son, 32 
 
 Dams, Courtney, 13 
 
 Masting and Rigging, Kipping, 
 
 21 
 Materials, Campin, 18 
 
 (Strength of), Barlow, 18 
 
 Handling of, Zimmer, 1 
 
 Mathematical Insts., Heather, 
 
 55 
 
 Heather &° Walmisley, 55 
 
 Tables, Law and Young, 
 
 22, 53 
 Mathematics, Campin, 53 
 Measures, Weights, &c, Wool- 
 house, 56 
 Measuring Builders' Work, 
 Dobson and Tarn, 33 
 
 Timber, &c, Horton, 33 
 
 Meat Production, Ewart, 50 
 Mechanical Dentistry, Hunter, 
 
 45 
 Engineering, Campin, 9 
 
 Handling of Material, 
 
 Zimmer, 1 
 
 Terms, Lockwood, 8 
 
 Mechanics, Hughes, 9 
 
 Lardner and Loewy, 40 
 
 Tomlinson, 10 
 
 — — of Air Machinery, Weis- 
 
 bach, 9, 22 
 — (Tables for), Smith, 8 
 
 Mechanics' Companion, Tem- 
 pleton and Hutton, 8 
 
 Workshop, Hasluck, 48 
 
 Mechanism, Baker, 10 
 Mensuration & Gauging, Mant, 
 
 41 
 and Measuring, Baker, 
 
 17 
 Metal Turning, Hasluck, 48 
 Metalliferous Minerals, Davies, 
 
 24 
 ■ Mining Machinery, Davies, 
 
 22 
 Metric Tables, Dowling, 49 
 Metrology, Jackson, 49 
 Microscope, Van Heurck, 40 
 Milk, Cheese, &c, Oliver, 50 
 Milling Machines, Horner, 2 
 Mine Drainage, Michell, 25 
 Mines of the Rand, Denny, 22 
 Mineral Surveyor, Lintern, 27 
 Mineralogy, Ramsay, 27 
 Miners' Handbook, Milne, 25 
 
 Pocket Book, Power, 24 
 
 Mining, British, Hunt, 24 
 Calculations, O'Donahue, 
 
 26 
 
 Chemistry of, Byrom, 26 
 
 Students, Notes for, Meri- 
 
 vale, 26 
 
 Tools, Morgans, 27 
 
 and Quarrying, Collins, 
 
 27 
 Model Engineer, Hasluck, 48 
 Mollusca, Woodward, 40 
 Motor Cars, Tayler, n, 47 
 
 Vehicles, Tayler, 1 1 
 
 Museum of Science and Art, 
 
 Lardner, 41 
 Music, Spencer, 56 
 
 Natural Philosophy, Tomlinson, 
 
 56 
 
 ■ for Schools, Lardner, 
 
 41 
 Naval Architect's Pocket Book, 
 Mackrow, 20 
 
 Architecture, Peake, 2 1 
 
 Navigation, Young, 22 
 
62 
 
 INDEX TO CATALOGUE. 
 
 Navigation, Greenwood and 
 
 Rosser, 21 
 Practical, 21 
 
 Oil Fields of Russia, Thompson, 
 22, 41 
 Oils, Analysis of, Wright, 41 
 Optical Instruments, Heather, 
 
 55 
 Optics, Lardner cV= Harding, 41 
 Organ Building, Dickson, 47 
 
 Packing Case Tables, Richard- 
 son, 38 
 Painting, Qullick &° Timbs, 40 
 Paper, Parkinson, 43 
 
 Making, Clapperton, 43 
 
 Watt, 43 
 
 Pastrycook's Guide, Wells, 46 
 Patents, Hardingham, 56 
 Pattern Making, Hasluck, 48 
 
 Horner, 8 
 
 Perspective, Ferguson, 33 
 
 Pywe, 34 
 
 Pianoforte, Spencer, 56 
 Pioneer Engineering, Dobson, 
 
 15 
 Plastering, Kemp, 33 
 Plating & Boilermaking, .Hor- 
 ner, 4 
 Plumbing, Buchan, 33 
 Pneumatics, Tomlinson, 19 
 Pocketbook, Agriculturist's, 
 Francis, 55 
 
 ■ McConnell, 52 
 
 ■ Builder's, Beaton, 33 
 
 ■ Electrical, Kempe, 30 
 
 Engineer's, Clark, 7 
 
 Edwards, 8 
 
 Fletcher, 8 
 
 ■ Hasluck, 9 
 
 Kempe, 7 
 
 Smith, 8 
 
 Templeton, 8 
 
 Engineman's, Reynolds, 6 
 
 Gas Engineer's, O'Connor, 
 
 43 
 — Health Officer's, Willoughby, 
 
 35 
 
 Pocketbook, Marine Engineer's, 
 
 Mackrow, 20 
 
 Wannan, 20 
 
 of Mensuration and 
 
 Measuring, Mant, 41 
 
 ■ Miner's, Milne, 25 
 
 Power, 24 
 
 — — Mining Prospecto r's, 
 
 Anderson, 24 
 
 — Merritt, 24 
 
 ■ Rankin, 23 
 
 ■ of Refrigeration, Tayler, 
 
 10 
 Portable Engine, Wansbrough, 
 
 5 
 Portland Cement, .Fai;a and 
 
 Butler, 33 
 Portuguese Dictionary, Elwes, 
 56 
 
 Grammar, Elwes, 56 
 
 Producer-Gas Plants, MatJwt, 6 
 Prospector's Handbook, Ander- 
 son, 24 
 Pumps and Pumping, 5a/e, 10 
 
 Quantities (Builders'), Beaton, 33 
 
 Railway Brakes, Reynolds, 6 
 
 Working, Stretton, 19 
 
 Reclamation of Land, Beazeley, 
 
 12 
 
 Refrigerating Machinery, Tay- 
 
 ler, 11 
 Refrigeration, Tayler, 10 
 
 (Pocket Book), Tayler, 1 1 
 
 River Bars, Mann, 14 
 Roads and Streets, Law, 16 
 Roof Carpentry, Collings, 37 
 Roofs, Construction of, Tarn, 
 iS 
 Rothamsted Experiments, 
 
 Tipper, 50 
 
 Sailmaking, Kipping, 21 
 
 Sadler, 21 
 
 Sanitary Work, Slagg, 36 
 Savouries and Sweets, Allen, 
 47 
 
INDEX TO CATALOGUE. 
 
 63 
 
 Saw Mills, Bale, 36 
 Screw Threads, Hasluck, 9 
 Sea Terms, Pirrie, 21 
 Sewage, Irrigation, Bum, 52 
 
 Purification, Barwise, 36 
 
 Sewing Machinery, Urquhart, 
 
 47 
 Sheep (The), Spooner, 50 
 Sheet-Metal Work, Crane, 46 
 
 Work, Warn &° Horner, 
 
 46 
 Shoring, Blagrove, 32 
 Ship Building, Sommerfeldt, 21 
 
 German, Felskowski, 21 
 
 Ships and Boats, Bland, 21 
 Silver, Metallurgy of, Eissler, 24 
 Silversmith's Handbook, Gee, 45 
 Slate Quarrying, Davies, 27 
 Slide Rule, Hoare, 53 
 Smithy and Forge, Crane, 9 
 Soap Making, Watt, 44 
 Soils, Bum, 50 
 Spanish Dictionary, Elwes, 56 
 
 Grammar, Elwes, 56 
 
 Specifications, Bartholomew, 31 
 
 in Detail, Macey, 31 
 
 Star Groups, Gore, 40 
 Statics, Graham, 17 
 
 and Dynamics, Baker, 55 
 
 Stationary Engine Driving, 
 Reynolds, 6 
 
 Steam Engines, Hurst, 6 
 
 Steam and Machinery Manage- 
 ment, Bale, 7 
 
 and Steam Engine, Clark, 
 
 10 
 Steam Boiler Construction, Hut- 
 ton, 3 
 
 ■ Boilers, Armstrong, 5 
 
 Wilson, 4 
 
 Engine, Baker, 6 
 
 Goodeve, 5 
 
 Haeder and Powles, 5 
 
 Lardner, 6 
 
 Safe Use of, 7 
 
 Stone Working Machinery, 
 
 Bale, n 
 Strains in Girders, Humber, 17 
 on Ironwork, Shields, 17 
 
 Submarine Telegraphs, Bright, 
 
 3° 
 Superficial Measuremnt, 
 
 Hawkings, 38 
 Survey Practice, Jackson, 14 
 Surveying, Baker and Dixon, 14 
 
 Frome and Warren, 15 
 
 Instruments, Heather, 55 
 
 Land & Marine, Haskoll, 14 
 
 Subterraneous, Fenwick, 27 
 
 Usill, 14 
 
 Whitelaw, 14 
 
 with Tacheometer, Ken- 
 nedy, 14 
 
 Tea Machinery, Tayler, 46 
 Technical Guide, Beaton, 33 
 
 Terms, Fletcher, 8 
 
 Timber Importer, Grandy, 37 
 
 Merchant, Dowsing, 37 
 
 Richardson, 38 
 
 Toothed Gearing, Homer, 9 
 Tramways, Clark, 16 
 Transmission by Electricity, 
 
 Atkinson, 29 
 Traverse Tables, Lintem, 27 
 Tree Planter, Wood, 53 
 
 Pruner, Wood, 53 
 
 Trigonometry, Plane, Hann, 55 
 
 ■ Spherical, Hann, 55 
 
 Trusses, Griffiths, 18 
 Tunnelling, Prelini and Hill, 15 
 
 Simms and Clark, 15 
 
 Tunnel Shafts, Buck, 16 
 Turning, Engineers', Horner, 2 
 
 Lathe, Hasluck, 9 
 
 Metal, Hasluck, 48 
 
 Wood, Hasluck, 48 
 
 Ventilation of Buildings, Buchan, 
 
 36 
 Villa Architecture, Wickes, 34 
 Visible Universe, Gore, 40 
 Vitruvius' Architecture, Gwilt, 
 
 35 
 Watch Jobbing, Hasluck, 48 
 
 Maker, Saunier, 44 
 
 Repairing, Garrard, 44 
 
 Watches, History of, Kendal, 45 
 
6 4 
 
 INDEX TO CATALOGUE. 
 
 Water Purification, Rideal, 35 
 
 ■ Engineering, Slagg, 13, 35 
 
 ■ Power of, Glynn, 13 
 
 Supply, Humber, 12, 35 
 
 Greenwell and Curry, 
 
 12,35 
 Supply of Towns, Burton, 
 
 "> 35 
 Waterworks, Hughes, 13 
 Well-Sinking, Swindell, 13 
 
 Wireless Telegraphy, Sewall, 29 
 Wood Carving for Amateurs, 40 
 
 Engraving, Brown, 47 
 
 Turning, Hasluck, 48 
 
 Woods and Marbles, Imitation 
 
 of, Van der Burg, 38 
 Woodworking, Hasluck, 48 
 
 Machinery, Bale, 36 
 
 Workshop Practice, Winlon, 9 
 Works' Manager, Hutton, 3 
 
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