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A SYSTEM V,n XX 
 
 CHEMISTRY APPLIED 
 
 DYEING. 
 
 BY 
 
 JAMES NAPIER, F. C. S. 
 A NEW AND THOROUGHLY REVISED EDITION, 
 
 COMPLETELY BROUGHT UP TO THE PRESENT STATE OF THE SCIENCE, 
 
 INCLUDING THE 
 
 CHEMISTRY OF COAL TAR COLORS. 
 
 BY 
 
 A. A. FESQUBT, 
 
 CHEMIST AND ENGINEER. 
 WITH AN 
 
 APPENDIX 
 
 ON DYEING AND CALICO PRINTING 
 
 AS SHOWN IN THE UNIVERSAL EXPOSITION, PARIS, 1867. 
 
 ILLUSTRATED. 
 
 1 1> $ I 
 
 PHILADELPHIA: 
 HENRY CAREY BAIRD, 
 
 INDUSTRIAL PUBLISHER, 
 406 Walnut Street. 
 1869. 
 
TP 
 
 c, \ 
 
 Entered according to Act of Congress, in the year 1869, by 
 
 HENRY CAREY BAIRD, 
 
 in the Clerk's Office of the District Court of the United States in and for the 
 Eastern District of the State of Pennsylvania. 
 
 PHILADELPHIA : 
 COLLINS, PRINTER, 705 JAYNE STREET. 
 
 THE GETTY CENTO?? 
 LIBRARY 
 
SECOND 
 
 PREFACE 
 
 TO THE 
 
 AMERICAN EDITION. 
 
 Napier's System of Chemistry Applied to Dyeing 
 fills a place in the literature of dyeing, which no other 
 book in the English language, with which we are ac- 
 quainted, does. It has passed through an edition each 
 in the United States and in England, and has for some 
 time been out of print in both countries. A steady and 
 pressing demand for it here, may be taken as conclusive 
 evidence of its usefulness, and of the estimation in which 
 it is held. That it is a book of great value, there can 
 be no question. 
 
 The present edition has been carefully revised and 
 edited throughout by Professor Fesquet, who has made 
 very many additions to it, especially upon the important 
 subject of Coal Tar Colors; and it is presented to the 
 American public with every feeling of confidence that it 
 will be found to give a faithful view of the present 
 state of the Science of Chemistry, from the dyer's stand- 
 point. 
 
 A full and carefully prepared index is added ; which 
 will render reference to any subject in the volume easy 
 and expeditious. 
 
 H. C. B. 
 
 Philadelphia, January 28, 1869, 
 
PREFACE TO THE LONDON EDITION. 
 
 If there be any trade which, more than another, requires 
 the knowledge of first principles, it is that of dyeing, it being 
 essentially progressive. The particular conditions of the trade 
 render information of this description more needful, and there- 
 fore more valuable, than ordinary. The trade is what is termed 
 open, so that any man may enter it ; and, in consequence, 
 there are few instances where young men are taught the busi- 
 ness systematically. A great many enter the trade who are 
 grown up — their chief ambition being to learn the mechani- 
 cal operations of the dye-house, and when sufficient dexterity in 
 these is attained, to secure the highest rate of wages. When 
 this is accomplished, zeal for improvement in a great measure 
 subsides. However, there are many who, not content with 
 acquiring a knowledge of the mere mechanical routine, desire 
 to look deeper into the principles of the art, and aim at higher 
 honors than those of a mere laborer in it, but who believe 
 that the means of success consist simply in long and steady 
 service, and a good memory for the rules of manipulation. 
 Both of these are valuable qualifications, but neither of them 
 would be depreciated in the slightest degree by being conjoined 
 with a more extended knowledge of the fundamental princi- 
 ples of the art than usually falls to the share of the practical 
 dyer. There is another evil arising out of this condition of 
 the trade. Individuals who attain the position of good work- 
 men, value their abilities by the contrast which exists between 
 
VI PREFACE TO THE LONDON EDITION. 
 
 them and the newly-initiated journeyman ; but they rarely or 
 never look forward to the wide field which lies unexplored 
 before them. Often, indeed, they boast of their capabilities, of 
 their expertness, and their knowledge ; and it is no uncommon 
 thing for them to indulge in petty jealousy, and endeavor to 
 conceal the secret of their mode of working from their neigh- 
 bors. Under these circumstances, it is no wonder that years 
 are often spent — we should say wasted — in endeavoring to 
 discover what was long before patent to every one who knew 
 the scientific principles of the trade, although ignorant of the 
 practical operations of it. This ignorance of principles often 
 makes both workman and master the dupes of knaves who go 
 about hawking valuable secrets at so much apiece. 
 
 It must be admitted, however, that notwithstanding all un- 
 toward circumstances, the degree of advancement which the 
 art has attained is truly astonishing. A single practical hint 
 is sometimes sufficient to cause a complete revolution in some 
 branch of the trade, so that were the principles of chemistry 
 in their application to dyeing but once generally understood 
 by those practically employed, we can hardly conceive what 
 changes and improvements might not be effected. 
 
 Another circumstance calling for. a few remarks is the fluc- 
 tuating state of the trade, which, even in its best condition, 
 throws not less than a fourth part of the workmen idle during 
 the winter months. But while we admit the hardship of 
 such a state of things in its fullest extent, we do not believe 
 that this time should be allowed to glide by in absolute list- 
 lessness. It is still a portion of the allotted span of life, and 
 ought to be turned to all the advantage which circumstances 
 will admit; and if it can be made subservient to future ad- 
 vantage either by advancing the personal interests, or in aug- 
 menting the mental enjoyment, of the individual, it is surely 
 culpable to allow it to run to waste. We sincerely believe 
 that it may be turned to account in both ways, and we promise 
 
PREFACE TO THE LONDON EDITION. vii 
 
 with some confidence that the following Treatise will suggest 
 the means of deriving remuneration even from idle hours. 
 Lord Bacon's maxim, that " Knowledge is power," has been 
 reiterated till it may be thought to have lost its virtue, but it 
 is still as true as ever, and we are confident that it cannot be 
 more aptly applied than to the case of the practical dyer. 
 
 From our own experience we are aware that there at 
 present exists a strong desire amongst a great many of those 
 employed in the processes of dyeing to understand the prin- 
 ciples of the art, and to be able to assign reasons for the 
 various changes that take place in producing the colors. Such 
 knowledge is often eagerly sought for without success, both 
 in books and in the lecture-room. The disappointment arises 
 from two sources : first, the inability of the dyer to apply 
 chemical principles to his special purposes ; and second, a 
 want of practical knowledge in the author or lecturer, which 
 disqualifies him for pointing out the special applications of 
 the principles he may be defining. These circumstances have 
 long impressed the Author with the opinion that an applica- 
 tion of principles to any practical operation can best be done 
 by an individual working at, or familiar with, all the practical 
 details of that particular operation or trade, and that every 
 branch of trade or art ought to have its own guide-book pre- 
 pared by one of its own operatives. The carrying out of this 
 idea has induced the Author to publish the present Manual, 
 which is a "System of Chemistry applied to Dyeing." 
 Having been himself a practical dyer for many years, and 
 having experienced the difficulties which an uneducated man 
 has to contend with in striving to become a Dyer in the proper 
 sense of the term, he has in the following pages endeavored to 
 clear away some of the technical difficulties besetting the path 
 of the practical man, and to guide him in following out first 
 principles while engaged in experiments to advance his art. 
 
 The Author acknowledges his obligations to a few intelligent 
 
viii 
 
 PREFACE TO THE LONDON EDITION. 
 
 dyers for several practical hints contained in these pages, and 
 which had not come under his own observation. It will also 
 be seen in reading the work, that advantage has been taken of 
 some valuable articles in foreign journals, translations of some 
 of which have appeared in chemical periodicals, such as the 
 Pharmaceutical Times, which is now discontinued, and the 
 Chemical Gazette, a journal which he earnestly recommends to 
 the practical dyer, as containing from time to time papers of 
 great value upon Dyeing and Dye-stuffs. 
 
 Partick, Glasgow. 
 
 i 
 
CONTENTS. 
 
 GENERAL PROPERTIES OF MATTER. 
 
 HEAT. 
 
 PAGE 
 
 Conditions of Matter 17 
 
 Heat the cause of Conditions of Matter 17 
 
 General Effects of Heat 19 
 
 Measures of Temperature 19 
 
 Boiling of Liquids 21 
 
 Substances affecting Boiling Point 21 
 
 Strong Boiling 22 
 
 Chemical Effects of Heat upon Colors 23 
 
 LIGHT. 
 
 Nature of Light . . .25 
 
 Relation of Colors to the Fabric 26 
 
 Effects of Different Rays upon Colors . . . ' . . .27 
 
 Effects of Light causing Combination ...... 28 
 
 Light Decomposes Chemical Compounds 29 
 
 Practical Application of the Principles 30 
 
 Harmonizing Colors 32 
 
 ELEMENTS OF MATTER. 
 
 Differences between an Element and Compound .... 34 
 
 Use of Symbols 36 
 
 Nomenclature 37 
 
 Rules for Naming Compounds 37 
 
 Salts — Their Nature and Nomenclature 39 
 
 CHEMICAL AFFINITY. 
 
 Application of Affinity 42 
 
 Circumstances influencing Affinity 42 
 
 Catalytic Influence 43 
 
 Constitution of Salts 44 
 
 Salt Radicals 45 
 
X CONTENTS, 
 
 ELEMENTARY SUBSTANCES. 
 
 PAGE 
 
 Oxygen ' . . . .47 
 
 How to make Oxygen Gas 48 
 
 Properties of Oxygen 49 
 
 Hydrogen .49 
 
 Water . . .50 
 
 Bin-oxide of Hydrogen 58 
 
 Nitrogen . . . . . .58 
 
 Protoxide of Nitrogen 60 
 
 Binoxide of Nitrogen 60 
 
 Nitrous Acid 61 
 
 Peroxide of Nitrogen 61 
 
 Nitric Acid 61 
 
 Table of the Quantity of Acids in 100 parts by weight . . 65 
 
 Ammonia 67 
 
 Chlorine 68 
 
 Hypochlorous Acid . .69 
 
 Hypochloric Acid 69 
 
 Chloric Acid 70 
 
 Hyperchloric Acid . 70 
 
 Hydrochloric Acid 70 
 
 Chloride of Nitrogen \ .74 
 
 Bleaching 75 
 
 Ozone ...... . . . . . . 93 
 
 Sulphur 93 
 
 Sulphurous Acid 94 
 
 Sulphuric Acid 95 
 
 Hyposulphurous Acid ........ 100 
 
 Hyposulphuric Acid 101 
 
 Sulphureted Hydrogen 10L 
 
 Selenium 103 
 
 Phosphorus 103 
 
 Iodine . . . . . 104 
 
 Bromine 105 
 
 Fluorine 105 
 
 Silicium 106 
 
 Boron 106 
 
 Carbon 106 
 
 Carbonic Oxide 108 
 
 Carbonic Acid . . . 108 
 
 Oxalic Acid 109 
 
 Cyanogen 110 
 
 Mellon Ill 
 
CONTENTS. xi 
 METALLIC SUBSTANCES. 
 
 PAGE 
 
 General Properties of Metals 112 
 
 Potassium 113 
 
 Potash .113 
 
 Sulphate of Potash 117 
 
 Bisulphate of Potash # . . . 117 
 
 Sulphite of Potash „ . . .118 
 
 Nitrate of Potash 118 
 
 Chlorate of Potash . . . 118 
 
 Phosphate of Potash 118 
 
 Oxalate of Potash . 118 
 
 Ferrocyanide of Potassium 119 
 
 Ferricyanide of Potassium 122 
 
 Cyanide of Potassium ........ 123 
 
 Cyanate of Potash 123 
 
 Sodium .. 123 
 
 Soda ... . . 124 
 
 Soda-Ash .125 
 
 Sulphate of Soda 129 
 
 Chloride of Sodium 130 
 
 Nitrate of Soda 130 
 
 Borate of Soda 130 
 
 Phosphate of Soda 130 
 
 Lithium . . 130 
 
 Soap 131 
 
 Barium . . . . 134 
 
 Strontium 135 
 
 Calcium . . 135 
 
 Caustic Lime . 135 
 
 Sulphate of Lime • . 136 
 
 Carbonate of Lime 136 
 
 Magnesium # 136 
 
 Magnesia .136 
 
 Aluminum . . . . . 137 
 
 Alumina 137 
 
 Alum 137 
 
 Sulphate of Alumina 141 
 
 Alum Cake . . 141 
 
 Aluminate of Soda ......... 141 
 
 Acetate of Alumina 141 
 
 Manganese . 149 
 
 Mineral Cameleon ......... 150 
 
 Iron 151 
 
 Sulphate of Iron 152 
 
 Chloride of Iron .... . . . . .157 
 
Xll 
 
 CONTENTS. 
 
 PAGE 
 
 Carbonate of Iron . 157 
 
 Acetate of Iron 157 
 
 Persulphate of Iron 158 
 
 Nitrate of Iron . . \ . . . . . . . . 158 
 
 Protosalts 161 
 
 Persalts of Iron . 162 
 
 Cobalt ! 162 
 
 Nickel • 163 
 
 Sulphate of Nickel . . . . 164 
 
 Chloride of Nickel 164 
 
 Nitrate of Nickel 164 
 
 Carbonate of Nickel 164 
 
 Zinc 164 
 
 Chloride of Zinc 165 
 
 Sulphate of Zinc 165 
 
 Nitrate of Zinc 165 
 
 Cadmium . . . 166 
 
 Copper . . . . . . . 167 
 
 Protoxide of Copper 167 
 
 Sulphate of Copper 168 
 
 Nitrate of Copper 168 
 
 Chloride of Copper . 168 
 
 Acetate of Copper . . . . 169 
 
 Oxalate of Copper 169 
 
 Arseniate and the Arsenite of Copper 169 
 
 Lead . . . 169 
 
 Suboxide of Lead 170 
 
 Protoxide of Lead ......... 170 
 
 Peroxide of Lead 171 
 
 Carbonate of Lead ......... 171 
 
 Nitrate of Lead 171 
 
 Acetate of Lead 171 
 
 Sulphate of Lead 173 
 
 Chloride of Lead 173 
 
 Testing the Value of Lead Salts ] 74 
 
 Bismuth . . . ' . . 174 
 
 Nitrate of Bismuth 175 
 
 Tin 175 
 
 Protoxide of Tin 177 
 
 Protochloride of Tin (Salts of Tin) 17 
 
 Protosulphate of Tin 178 
 
 Protonitrate of Tin 178 
 
 Tartrate of Potash and Tin 178 
 
 Stanno-Arsenite of Soda 178 
 
 Deutoxide or Sesquioxide of Tin 17 
 
 Peroxide of Tin 179 
 
CONTENTS. Xlii 
 
 PAGE 
 
 Perchloride of Tin 180 
 
 Spirits 181 
 
 Red Spirits 182 
 
 Plumb Spirits 183 
 
 Barwood Spirits 183 
 
 Yellow Spirits 183 
 
 Acetate of Tin 183 
 
 Oxalate of Tin 183 
 
 Titanium 184 
 
 Chromium 185 
 
 Chloride of Chromium 186 
 
 Sulphate of Chromium ........ 186 
 
 Chromic Acid 187 
 
 Bichromate (Red Chromate) of Potash . . . . . 188 
 
 Chromate of Lead 189 
 
 Chrome Yellow 189 
 
 Chrome Greens . . 191 
 
 Chrome Orange 191 
 
 Tests for Bichromate of Potash 193 
 
 Vanadium 193 
 
 tungstenum, or wolfram . . 194 
 
 Molybdenum 195 
 
 Peroxide of Molybdenum . . . . . . . . 195 
 
 Molybdic Acid 195 
 
 Tellurium 196 
 
 Tellurous Acid 196 
 
 Telluric Acid 196 
 
 Arsenic 196 
 
 Arsenious Acid 197 
 
 Arsenic Acid 198 
 
 Sulphurets of Arsenic 198 
 
 Antimony 199 
 
 Oxide of Antimony 199 
 
 Sulphate of Antimony 199 
 
 Antimonious Acid 200 
 
 Antimonic Acid 200 
 
 Uranium 200 
 
 Protoxide of Uranium 200 
 
 Peroxide of Uranium 201 
 
 Cerium 201 
 
 Mercury 202 
 
 Suboxide of Mercury . . . . . . . . 202 
 
 Protoxide of Mercury — Peroxide of Mercury .... 202 
 
 Silver 203 
 
 Nitrate of Silver .204 
 
 Sulphate of Silver 204 
 
xiv 
 
 CONTENTS. 
 
 PAGE 
 
 Gold 205 
 
 Subch'loride of Gold 206 
 
 Perehloride of Gold 206 
 
 Platinum '. ... 206 
 
 Palladium , 207 
 
 Iridium) 208 
 
 Osmium . . ... . .... . . 209 
 
 Khodium 209 
 
 Lanthanium . 210 
 
 TEXTILE FIBRES. 
 
 Cotton 211 
 
 Flax . . . . . ' . . . ... . .211 
 
 Hemp 212 
 
 Silk . . , 212 
 
 Wool . . .212 
 
 Generalities on Textile Fibres 213 
 
 MORDANTS. 
 
 Red Spirits . . . . . . . . . . ' . 224 
 
 Barwood Spirits . . . 225 
 
 Plum Spirits . .226 
 
 Yellow Spirits 226 
 
 Nitrate of Iron . . . . . .... . . . 227 
 
 Acetate of Iron and Alumina . . 227 
 
 Acetate of Alumina . . . . . . . . . 227 
 
 Black Iron Liquor . . . 227 
 
 Iron and Tin for Royal Blue . . . ... . . . .227 
 
 Acetate of Copper 228 
 
 VEGETABLE MATTERS USED IN DYEING. 
 
 Introductory Remarks . . 234 
 
 Galls 241 
 
 Sumach . . 249 
 
 Catechu ... 254 
 
 Valonia Nuts 258 
 
 Divi Divi 258 
 
 Myrobalans 258 
 
 INDIGO. 
 
 Manufacture of Indigo 261 
 
 Testing of Indigo 266 
 
 Commercial Indigoes 274 
 
 Characteristics of Indigo . 276 
 
 Indigo Dyeing .... 281 
 
CONTENTS. 
 
 XV 
 
 PAGE 
 
 Sulpho-purpuric Acid 283 
 
 Sulphate of Indigo 285 
 
 Indigo Extract 285 
 
 The Blue Yat 287 
 
 Woad and Pastel - . 292 
 
 Indigo Blue . 292 
 
 Pastel Yat . . .294 
 
 Woad Yat 297 
 
 Modified Pastel Yat 298 
 
 Indian Yat . .299 
 
 PqtashYat 300 
 
 German Yat ... 300 
 
 Management of the Vats 302 
 
 Logwood 306 
 
 Brazil Woods . . . . . .. . ." . . 314 
 
 Santal or Sandal Wood 317 
 
 Barwood 317 
 
 Camwood 320 
 
 Fustic or Yellow Wood 321 
 
 Young Fustic 322 
 
 Bark or Quercitron . . 323 
 
 Flavine . 325 
 
 Extracts of Woods 326 
 
 Weld or Wold 326 
 
 Turmeric 328 
 
 Persian Brrries 328 
 
 Safflower or Carthamus . 329 
 
 Madder 333 
 
 Levant Madder 334 
 
 Dutch Madder 334 
 
 Alsace Madder . . . 335 
 
 Madder of Avignon . . 335 
 
 Madder Purple . 338 
 
 Madder Ked 338 
 
 Madder Orange 339 
 
 Madder Yellow . . . . . . . ■ . . . 339 
 
 Madder Brown . . . ....... 339 
 
 Madder Acids 339 
 
 Useful Products . 339 
 
 Madder Preparations 340 
 
 Chlorine 343 
 
 Coloring Principles of Madder 344 
 
 Tests for Madder 346 
 
 Munjeet . . . 348 
 
 Annotta or Arnotto 348 
 
 Alkanet Root . 352 
 
 Archil 352 
 
xvi CONTENTS. 
 
 PEOPOSED NEW VEGETABLE DYES. 
 
 PAGE 
 
 SoORANJEE 355 
 
 Carajuru or Chica 358 
 
 Wongshy 359 
 
 Aloes 363 
 
 PlTTACAL 364 
 
 Barbary Koot 364 
 
 ANIMAL MATTERS USED IN DYEING. 
 
 Cochineal 365 
 
 Carmine 366 
 
 Lake Lake or Lac . . . 370 
 
 Kerms or Kermes .371 
 
 MUREXIDE 371 
 
 COLORS DERIVED FROM COAL TAR. 
 
 Production of Coal Tar 373 
 
 Composition of Coal Tar 373 
 
 Distillation of Coal Tar . 374 
 
 Aniline 375 
 
 Theory of Aniline Colors 377 
 
 Aniline Reds \ . .380 
 
 Aniline Blues and Yiolets 381 
 
 Aniline Yellows 382 
 
 Aniline Greens 383 
 
 Aniline Blacks and Grays 384 
 
 Aniline Browns and Maroons . . 385 
 
 Colors derived from Carbolic or Phenic Acid .... 385 
 
 Colors derived from Naphthaline 387 
 
 Remarks in General on Coal Tar Colors 388 
 
 Remarks in General on Dyeing with Coal Tar Colors . . . 389 
 Determination of the Coloring Power and Nature of Aniline 
 
 Colors 391 
 
 Identification of Aniline Colors . ... . . . 392 
 
 APPENDIX. 
 
 Dyeing and Calico Printing as shown in the Universal Exposition, 
 Paris, 1867 
 
 Extracts from the Reports of the International Jury, and from other 
 
 Sources 395 
 
 Glossary of Technical Terms used in the Dye-House with the 
 
 Chemical Names 399 
 
 Index 403 
 
A SYSTEM 
 
 OF 
 
 CHEMISTRY APPLIED TO DYEING. 
 
 GENERAL PROPERTIES OF MATTER. 
 
 HEAT. 
 
 Conditions of Matter. — Matter, which is everything ca- 
 pable of affecting the senses, exists in three different states — 
 solid, fluid, and gaseous. Looking upon matter in any of these 
 states, the most casual observer cannot fail to distinguish a 
 great variety of appearance. For example — stone differs from 
 brick, bread from wood, and iron from both, among the solid 
 forms; while differences quite as great are seen both in fluids 
 and amongst gases. But, although these differences are familiar 
 to all, there are few who inquire the cause why, under the same 
 circumstances, one portion of matter exists as a solid, another 
 as a fluid, and a third as a gas. Correct answers to these in- 
 quiries are the objects of all scientific research. They are, in 
 their nature twofold — physical and chemical. The former, em- 
 bracing the study of matter in mass, takes cognizance of shape, 
 measure, hardness, weight, flexibility, tenacity, divisibility, and 
 such like properties; while the latter, the chemical, investigates 
 those more remote differences which depend on the relative 
 powers, properties, and mutual actions of the elemental com- 
 ponents of the given substance — an inquiry which embraces a 
 universal interrogation of all kinds of matter. 
 
 Heat the Cause of Conditions of Matter. — That one 
 body is solid, another fluid, and a third gaseous, is an inquiry 
 which belongs more directly to physics than to chemistry ; yet 
 heat, which is the cause of these differences, is so intimately 
 connected both with the molecular changes, and the constitution 
 of bodies, particularly of the coloring matters used in dyeing, 
 that it will be proper to enumerate, preliminarily, a few of its 
 most prominent effects and general laws, for convenience of 
 2 
 
18 
 
 HEAT THE CAUSE OF CONDITIONS OF MATTER. 
 
 frequent reference when we come to speak of the practical effects 
 of those laws on many of the operations in the dye-house. 
 
 All bodies are' supposed capable of existing in the three states 
 — solid, fluid, and gaseous — by the addition or subtraction of 
 heat ; but the same degree of heat does not affect all kinds of 
 bodies to the same extent. For example — water, subject to 
 the ordinary pressure of the atmosphere, at 32° Fah. and under, 
 is solid; from 32° to 212° it is fluid; and from 212° upwards it 
 is gaseous; while quicksilver, another fluid, at ordinary tem- 
 perature, does not become solid until it is cooled 72° below that 
 of the solidifying point of water, and does not pass into the 
 gaseous state until it is heated upwards of 400° above the 
 aeriform point of water. Again, lead and several other bodies 
 only become fluid at the temperature which gassifies quicksilver. 
 The following table will make this more apparent: — 
 
 
 Solid 
 
 Becomes 
 
 Becomes 
 
 Range of 
 
 
 matter 
 
 fluid at 
 
 gaseous at 
 
 fluidity. 
 
 Sulphurous Acid about 
 
 —105 
 
 about — 105 
 
 +12 to +14 
 
 118 
 
 
 ' + 32 and a pres- 
 
 
 
 Carbonic Acid about 
 
 —112- 
 
 sure of 36 atmo- 
 
 | -71(0 
 
 
 
 
 spheres 
 
 
 Mercury 
 
 — 39 
 
 — 39 
 
 +662 
 
 701 
 
 Water. 
 
 + 32 
 
 + 32 
 
 +212 
 
 180 
 
 Tin ... 
 
 442 
 
 442 
 
 about 2400 
 
 about 1958 
 
 Lead .... 
 
 626 
 
 626 
 
 Not known 
 
 
 Bismuth 
 
 480 
 
 480 
 
 a u 
 
 
 Arsenic 
 
 356 
 
 Under pressure 
 
 Dark red heat 
 
 
 Silver . . ... 
 
 2283 
 
 2283 
 
 Not known 
 
 
 Cast-Iron 
 
 3479 
 
 3479 
 
 ft it 
 
 
 This table shows how differently the same degree of heat 
 affects different substances. W4 cannot conceive a condition 
 so cold that all matter would be solid, nor so hot that all would 
 be gaseous. In the cases of carbonic acid and arsenic, there 
 appears an exception: these bodies have no fluid range — 
 they have no existence in a fluid state. They may be ob- 
 tained fluid by pressure; but this is under extraordinary cir- 
 cumstances, and the particles still retain their elasticity, which 
 a true fluid does not. But when in the solid state, and under 
 ordinary conditions — that is, under the ordinary pressure of the 
 atmosphere — it passes directly from the solid to the gaseous state. 
 
 Some philosophers, reasoning from analogy, and not admit- 
 ting any exceptions to general laws in nature, object to the 
 apparent fact, and give, as their opinion, that such substances 
 as carbonic acid really have a fluid range, but being so little, 
 probably only a few degrees, the body may pass through that 
 state without observation. This supposition is untenable, and 
 is founded upon a mistaken view of what is a general law. 
 The range of fluidity of any body depends upon the amount 
 
MEASURES OF TEMPERATURE. 
 
 19 
 
 of pressure which the body is subject to. There are many 
 other bodies, besides carbonic acid and arsenic, that require a 
 greater amount of pressure than that of our atmosphere to 
 maintain them in the fluid state; so that both the facts and 
 the circumstances are quite in accordance with the general 
 laws of nature. 
 
 General Effects of Heat. — In connection with the ge- 
 neral laws of heat, we may notice, first, that bodies when they 
 become heated expand, or become larger — the particles which 
 compose them seem to separate farther from one another. 
 This effect is produced upon matter in all states. Familiar 
 illustrations of this effect of heat are numerous. If a pair of 
 tongs, with legs of equal length, have one of the legs put into 
 the fire and made red hot, it will be found, in this state, longer 
 than the other. It is well known to dyers, that if a boiler 
 be filled to within a little of the mouth with cold water, and 
 a fire put under it, by the time it begins to boil the water runs 
 over, having enlarged so much that the boiler is too small to 
 contain it when hot. And another circumstance often occurs — 
 when a certain quantity of a decoction of a dye is required, 
 and is measured out of the boiler in gross while hot, and then 
 distributed in its required proportions when cold, there is often 
 wanting a considerable portion of liquid, causing serious annoy- 
 ances in the dye-house, when the difference of temperature is 
 not taken into consideration. 
 
 That gaseous bodies are affected in the same way by heat, 
 may be illustrated by taking a bladder, and filling it three 
 parts full with cold air, tying it round the neck, and holding 
 it before a fire — or, what is better, taking the bladder into the 
 drying-stove connected with the dye-house. In a very little 
 time the bladder becomes distended and quite full, and may 
 be made to burst by the expansion of the air, if the heat be 
 high, or the bladder nearly filled. 
 
 Measures of Temperature. — Upon this expansive effect 
 of heat is founded the means of measuring its intensity. Our 
 senses tell us when a body is hot or cold, but they are very 
 imperfect indicators of the degree or intensity of the heat. 
 Our own temperature being the standard, we can only tell 
 that a substance is hotter or colder than our own body. In 
 the dye-house, where the hand is often made the indicator of the 
 temperature of the dyeing liquid, the result varies according to 
 whether the person has been previously working in hot or cold 
 liquids, and is therefore a very imperfect test of temperature, 
 and often productive of evils by giving different tints of shades, 
 and deteriorating the beauty of a color. Temperature is very 
 correctly measured by observing the amount of expansion in 
 
20 
 
 COMPARATIVE VALUE OF THE SCALES. 
 
 any given body. Instruments for this purpose are plentiful 
 and cheap; we will therefore not require to detail' their mode 
 of manufacture, but a good thermometer is an essential instru- 
 ment in the dye-house, and ought to be constantly employed. 
 The thermometers used in this country are generally those of 
 Fahrenheit. The scale of measurement of this has been deter- 
 mined in the following manner: Fahrenheit divided the two 
 points, from the freezing of water to its boiling, into 180 deg- 
 rees ; he called the freezing point the 32d degree, from some 
 reason of his own; hence 32° + 180° = 212, the boiling point 
 of water, according to Fahrenheit. There is another scale 
 sometimes used, called Reaumur's. This has the two points, from 
 the freezing to the boiling of water, divided into 80 degrees. 
 Another, and more generally used scale, has the range from 
 freezing point to boiling of water divided into 100° ; thus the 
 freezing point is marked 0, the boiling point 100. This is 
 termed the Centigrade thermometer. In reading books where 
 temperature is referred to — such as in many dyeing recipes 
 and processes — attention must be paid which thermometer 
 scale is referred to. They are generally indicated by abbrevia- 
 tions — as F., or Fah., for Fahrenheit's scale, R., or Reau., for 
 Reaumur's, and C. for the Centigrade. The following table of 
 the comparative value of the different scales, will guide the 
 operator in using one or other of them : — 
 
 Gent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 0 . . 
 
 . 32 
 
 21 . . 
 
 . 69.8 
 
 42 . . 
 
 . 107.6 
 
 1 . 
 
 . 33.8 
 
 22 . . 
 
 . 71.6 
 
 43 . . 
 
 . 109.4 
 
 2 . 
 
 . 35.6 
 
 23 . . 
 
 . 73.4 
 
 44 . . 
 
 . 111.2 
 
 3 . 
 
 . 37.4 
 
 24 . 
 
 . 75.2 
 
 45 . . 
 
 . 113 
 
 4 . 
 
 . . 39.2 
 
 25 . . 
 
 . 77 
 
 46 . . 
 
 . 114.8 
 
 5 . 
 
 . 41 
 
 26 . . 
 
 . 78.8 
 
 47 . . 
 
 . 116.6 
 
 6 . 
 
 . 42.8 
 
 27. . 
 
 . 80.6 
 
 48 . . 
 
 . 118.4 
 
 7 . 
 
 . . 44.6 
 
 28 . . 
 
 . 82.4 
 
 49 . . 
 
 . 120.2 
 
 8 . 
 
 . . 46.4 
 
 29 . . 
 
 . 84.2 
 
 50. . 
 
 . 122 
 
 9 . 
 
 . . 4«.2 
 
 30. . 
 
 . 86 
 
 51 . . 
 
 . 123.8 
 
 10 . 
 
 . . 50 
 
 31 . . 
 
 . 87.8 
 
 52 .. . 
 
 . 125.6 
 
 11 . 
 
 . . 51.8 
 
 32 . . 
 
 . 89.6 
 
 53 . . 
 
 . 127.4 
 
 12 . 
 
 . . 53.6 
 
 33 . . 
 
 . 91.4 
 
 54 . . 
 
 . 129.2 
 
 13 . 
 
 . . 55.4 
 
 34 . . 
 
 . 93.2 
 
 55 . . 
 
 . 131 
 
 14 . 
 
 . . 57.2 
 
 35 . . 
 
 . 95 
 
 56 . . 
 
 . 132.8 
 
 15 . 
 
 . . 59 
 
 36 . . 
 
 . 96.8 
 
 57 . . 
 
 . 134.6 
 
 16 . 
 
 . . 60.8 
 
 37 . . 
 
 . 98.6 
 
 58 . . 
 
 . 136.4 
 
 17 . 
 
 . . 62.6 
 
 38 . . 
 
 . 100.4 
 
 59 . . 
 
 . 138.2 
 
 18 . 
 
 . . 64.4 
 
 39 . . 
 
 . 102.2 
 
 60 . . 
 
 . 140 
 
 19 . 
 
 . . 66.2 
 
 40 . . 
 
 . 104 
 
 61 . . 
 
 . 141.8 
 
 20 . 
 
 . . 68 
 
 41 . . 
 
 . 105.8 
 
 62 . . 
 
 . 143.6 
 
SUBSTANCES AFFECTING BOILING POINT. 21 
 
 Cent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 63 . . 
 
 . 145.4 
 
 76 . . 
 
 . 168.8 
 
 89 . . 
 
 . 192.2 
 
 64 . . 
 
 . 147.2 
 
 77 . . 
 
 . 170.6 
 
 90 . . 
 
 . 194 
 
 65 . . 
 
 . 149 
 
 78 . . 
 
 . 172.4 
 
 91 . . 
 
 . 195.8 
 
 66 . . 
 
 . 150.8 
 
 79 . . 
 
 . 174.2 
 
 92 . . 
 
 . 197.6 
 
 67 . . 
 
 . 152.6 
 
 80 . . 
 
 . 176 
 
 93 . . 
 
 . 199.4 
 
 68 . . 
 
 . 154.4 
 
 81 . 
 
 . 177.8 
 
 94 . . 
 
 . 201.2 
 
 69 . . 
 
 . 156.2 
 
 82 . 
 
 . 179.6 
 
 95 . . 
 
 . 203 
 
 70 . . 
 
 . 158 
 
 83 . . 
 
 . 181.4 
 
 96 . . 
 
 . 204.8 
 
 71 . . 
 
 . 159.8 
 
 84 . 
 
 . 183.2 
 
 97. . 
 
 . 206.6 
 
 72 . . 
 
 . 161.6 
 
 85 . . 
 
 . 185 
 
 98 . . 
 
 . 208.4 
 
 73 . . 
 
 . 163.4 
 
 86 . . 
 
 . 186.8 
 
 99 . 
 
 . 210.2 
 
 74 . . 
 
 . 165.2 
 
 87 . 
 
 . 188.6 
 
 100 . 
 
 . 212 
 
 75. . 
 
 . 167 
 
 88 . 
 
 . 190.4 
 
 
 
 It will be seen from this table that every 5 degrees of the 
 Centigrade scale is equal to 9 Farenheit ; so that any degree of 
 the one may be converted into the other by a simple rule, 
 namely, by multiplying the Centigrade by 9, and dividing by 
 5, then adding 32°. Thus, if any liquid is recommended to be 
 at 60° C, then 60° Cent, x 9 ~ 5 + 32° = 140° F. ; or by 
 Reaumur's, the only difference in the process is to divide by 4 
 instead of by 5. Thus, 60° R, x 9-4 + 32° = 167° F. 
 
 Boiling of Liquids. — The heating and boiling of liquids is 
 explainable by the principle of expansion. When heat is 
 applied to a vessel holding water, the particles of water nearest 
 the fire become heated, and consequently expand ; and, in this 
 expanded state, being lighter than the particles above them, 
 they rise to the surface, and give place to another layer of par- 
 ticles. These particles are in turn heated, and rise to the sur- 
 face ; and so on, successively, until the fluid is all heated to the 
 point at which it passes off as vapor or steam. The exact 
 temperature at which this takes place is stated above as 212° 
 Fah., but varies a little from the amount of pressure upon its 
 surface, so that water boils at a lower heat upon a high hill 
 than at the foot of it ; and, for the same reason, it requires a 
 higher temperature to boil the water at the bottom of a deep 
 pit than upon the surface at the mouth of the pit, there being 
 a greater pressure of air at the bottom of the pit in proportion 
 to the depth. 
 
 Substances affecting Boiling Point. — Anything that 
 gives an increased attraction to the particles of a fluid also 
 raises the temperature of the boiling point. Some kinds of ves- 
 sels, such as glass and polished metals, retain the water with 
 greater force than rough vessels, hence it requires a little 
 higher heat to boil water in vessels of polished material. 
 
22 
 
 STRONG BOILING. 
 
 Water, upon the surface of oil, boils two degrees of heat below 
 water in a glass vessel, in consequence of the oil having no 
 attraction for water. 
 
 Substances dissolved in water have often a similar effect, the 
 attraction of the two substances having to be overcome. Thus, 
 alkaline lyes — soda or potash dissolved in water — require higher 
 temperatures to boil them than pure water does. But, connected 
 with this, we may mention a circumstance of great importance 
 in the dye house. In boiling alkaline lyes, so strong is the 
 attraction of the water for the alkali, that it carries a small 
 quantity with it in passing off* as steam ; so that great care 
 should be taken in a dye-house where lyes are being boiled, 
 that the steam or vapor does not come into contact with any 
 colors that will be affected by alkalies. Whei:e convenient, 
 it is, indeed, safest to have all alkaline lyes boiled entirely 
 apart from w r here any colored goods are likely to be exposed 
 to the influence of these vapors. We have seen many annoying 
 and expensive accidents caused by neglecting this precaution, 
 especially upon such colors as safflower reds, and Prussian 
 blues. 
 
 Strong Boiling. — Another circumstance of common occur- 
 rence in the dye-house is what is termed strong boiling. This 
 means that, in the process of boiling, we increase the fire, in 
 order to give the liquor more heat, and make it hotter. We 
 need hardly say that this is an error; for a liquid at the boil- 
 ing point cannot be more heated by increase of fire. All that 
 is required is as much heat as will retain it on the spring of 
 the boil, and the liquid will then be as hot as though it boiled 
 with the greatest violence. The only difference in strong 
 boiling is, that much more steam is driven off, which carries 
 off the heat applied, and lessens the quantity of solution ; still, 
 if a thermometer be placed in the liquor, the temperature is 
 found to be the same, and the only effect is that the heat is 
 more rapidly carried off by the steam, and lost. The amount 
 of heat which steam thus imbibes and takes away, is calculated 
 in round numbers, at 1000° Fah., which may be illustrated as 
 follows : If one pound of water, at 32°, requires the burning of 
 a' pound of coal to bring it to the boiling point (212°), the 
 water will have received 180° of heat; if the fire be continued 
 at the same rate, it will take 5 J lbs. of coal to convert the 
 pound of boiling water into steam, and the temperature of the 
 steam will never be above 212° Fah.; thus 1000° of heat have 
 been taken up by the steam, and retained in a latent state — 
 that is to say, in a state not sensible to the thermometer. Or 
 we may illustrate this principle by another experiment: if we 
 take 5 J lbs. of water at 32°, and pass a jet of steam at 212° 
 
CHEMICAL EFFECTS OF HEAT UPON COLORS. 
 
 23 
 
 through it, until the water begins to boil, the whole water will 
 weigh lbs.; thus 1 lb. of steam has brought 5| lbs. of water 
 up 180°, thereby showing that this pound of steam had con- 
 tained 1000° of heat. These facts the practical dyer can easily 
 apply to his own purposes. Steam is very generally used in 
 the dye-house as a heating agent for water, making decoctions, 
 and the boiling of goods. It is an observed fact that steam is 
 not so effective for many purposes as fire — as in the making of 
 some decoctions. In the using of steam for boiling, some of 
 the circumstances referred to ought to be kept in mind, such as 
 the fact that steam cannot raise the temperature of 'the boiling 
 liquid above 212°. Hence the conditions noticed of the raising 
 the boiling point of water by the presence of matters held in 
 solution, and by different kinds of vessels, do not apply to 
 liquids when boiled by steam. This may be one cause of the 
 observed difference of effect in the dye-house. Again, water 
 boiled by passing a jet of ordinary pressure steam into it, never 
 gets above 210°, a small deficiency, but sufficient to cause a 
 difference in the results of many operations in the workshop. 
 
 This fact may be accounted for by the circumstance that in 
 this process there is no attraction of the water by the surface 
 of the vessel, as when boiled by fire, which, as has been ob- 
 served by Berzelius, causes the boiling point in different vessels 
 to vary upwards of 2°. In boiling by steam, no such attraction 
 has to be overcome as that between the vessel and water ; 
 hence the boiling point is lower, and 210° may be actually the 
 true boiling point of water. For all ordinary purposes, 
 however, steam, as a heating agent, is of the highest value to 
 the dyer. 
 
 Chemical Effects of Heat upon" Colors. — The effects of 
 heat in relation to chemical combination and decomposition, 
 are of the utmost importance in all the operations of the dyer. 
 The influence of heat in producing particular tints and colors, 
 and also upon many colors when produced, are subjects of 
 every-day observation. Nevertheless, the consequences are 
 often so important, that the subject cannot be too fully im- 
 pressed upon the minds of all interested. We shall, therefore, 
 enumerate a few of the more prominent effects in this place. 
 
 In making a decoction of quercitron bark, for dyeing yellow, 
 if it is made at a temperature of about 90°, a much finer and 
 purer yellow is obtained than when the decoction is made by 
 boiling. When woollen cloth is dyed by bark, and then hot- 
 pressed, the heat impairs the color ; but generally dyed colors 
 are more liable to be affected by heat when moisture is present, 
 than in a dry atmosphere. For instance — a safflower red will 
 stand a high temperature when the air is dry, but if moisture be 
 
24 
 
 CHEMICAL EFFECTS OF HEAT UPON COLOKS. 
 
 present, it passes rapidly into a yellowish brown. If a Prussian 
 blue be placed in a moist atmosphere, and raised to the tempera- 
 ture of about 300° Fah., it fades entirely in a few hours. Many 
 of the coloring matters of flowers, when imparted to cloth ; may 
 be dried without change in the cold and dark, and afterwards 
 be submitted to a temperature of 200° without alteration, but 
 could not stand a temperature of 95° without being altered 
 were these precautions not taken ; such colors, therefore, if put 
 on goods, could not be dried in a stove. 
 
 The kind of material on which the color is dyed also influ- 
 ences the effects of heat. Indigo blue dyed upon cotton is 
 permanent, exposed to heat and moisture ; but the same color, 
 with the same dyestuff, upon silk, is readily changed under 
 those conditions. Safflower colors upon silk and cotton, placed 
 under similar circumstances in regard to heat and moisture, 
 are affected oppositely ; that on the cotton is completely de- 
 stroyed before that upon the silk is at all affected. 
 
 Thus we find that heat operates upon colors differently when 
 the heated atmosphere or color is dry and when it is moist, 
 which suggests the propriety of paying strict attention to the 
 condition of the drying-stove, and the hanging of the colored 
 fabrics, so as to give a free outlet to all moisture. If this is 
 neglected, the colors are subjected to a hot vapor-bath, and are 
 under the most favorable conditions to be destroyed by the 
 joint action of the heat and steam. 
 
 The same kind of coloring matter fixed upon cotton by dif- 
 ferent mordants, is affected by heat differently, whether mois- 
 ture be present or not. This can be observed daily of logwood 
 colors, when fixed by tin or by alumina. The different 
 changes which these colors undergo in the process of drying, 
 and the dependence of these upon the state of the stove, as to 
 being hot and dry or hot and moist, are familiar to the practical 
 dyer. But as we shall have occasion to notice some of these 
 changes when describing the dyestufts, and the colors produced, 
 we pass over the details in this place. The following, how- 
 ever, may be stated as a general rule, namely — that all organic 
 coloring matters are destroyed at a red heat. There are some, 
 however, such as indigo, which sublime, or may be distilled 
 by a heat less than sufficient to effect their destruction. 
 Those coloring matters which are volatile are in general most 
 permanent when fixed upon fabrics, and resist the action of 
 heat best; and those colors that do not sublime are most sus- 
 ceptible of decomposition under the combined influence of air, 
 heat, and moisture. 
 
25 
 
 LIGHT. 
 
 Nature of Light. — The effects of light upon colors are so 
 closely related to that of heat, and so powerful — particularly 
 the direct rays of the sun — that we cannot pass over the con- 
 sideration of those accidental phenomena, which we must un- 
 derstand as independent altogether of that essential relation 
 which light has to produce color. Strictly speaking, colors 
 have no material existence, but are altogether the effect of 
 light — at least, colors do not exist in the objects appearing 
 colored, but in the light which is reflected from the apparently 
 colored object. In order, then, to define color, we may briefly 
 state what is known upon the nature and composition of light 
 — at least, so far as is necessary for our present purpose. 
 
 A beam of light is composed of three differently colored 
 rays — red, blue, and yellow — termed sometimes the luminous, 
 calorific, and chemical rays, from their different properties of 
 giving out heat and light, or in exciting chemical action. 
 When a beam of light strikes the surface of a body, it bounds 
 off as an elastic ball would do striking the same surface, and 
 this bounding off is termed reflection ; or, it is absorbed by 
 the body and disappears, and is altogether extinguished; or, 
 lastly, it passes through the body, making it transparent. In 
 the first case, the bounding or reflected rays pass into the eye, 
 and the body from which it is reflected appears white or some 
 particular color. In the second place, there can no light pro- 
 ceed from the object to the eye, it being absorbed and ex- 
 tinguished — the body, therefore, is invisible ; or, if the sur- 
 rounding objects are illuminated, or reflect light, it appears 
 black ; and, in the third place, the light passing through un- 
 altered, the body appears clear. The less the light is altered, 
 the more clear and transparent the body, and consequently 
 the more nearly invisible. Thus, that which we are accus- 
 tomed to call white light is the simultaneous transmission of 
 three colored rays. Thus also, when light is admitted into 
 a dark room through a small aperture — say a hole in a window- 
 shutter — and a glass prism is placed in the aperture, so that 
 the light passes through it and is made to fall upon a sheet of 
 white paper, the light is decomposed, and appears upon the 
 paper in the following order of colors: — 
 
26 
 
 RELATION OF COLORS TO THE FABRIC. 
 
 Violet. » Green. Orange. 
 
 Indigo. *Yellow. *Ked. 
 
 *Blue. 
 
 These are termed the seven prismatic colors, and the share 
 they all occupy is termed the spectrum, of which each occu- 
 pies a definite breadth. Those marked by a * are the only 
 simple colors — that is, requiring no admixture — the others are 
 produced by a mixture of different colors, and are therefore 
 compound. The violet and indigo, for example, are composed 
 of a mixture of blue and red; the green is a mixture of blue 
 and yellow, and the orange of yellow and red. Hence the 
 primary colors are blue, red, and yellow. The equal admixture 
 of these three colors gives white light ; but anything disturbing 
 that simultaneous equality, produces a color according to the 
 nature and amount of disturbance. Thus, the prism through 
 which the light entered the room, in the experiment referred 
 to, from its shape and properties effects a complete disturbance, 
 and the different colors are made visible. Similar effects are 
 produced, as has been already stated, when the light is reflected 
 from a surface. If the different colored rays are not reflected 
 or absorbed in the same ratio, the result is a color according to 
 the difference in the reflection or absorption of the different ray 
 or rays. If the red ray is absorbed, and only the blue and 
 yellow rays reflected, the object from which they are reflected 
 appears green ; if the yellow ray is also absorbed, the object 
 appears blue ; or if it has been the blue ray that is absorbed, 
 and red and yellow reflected, the object appears orange ; or if 
 the yellow ray only is absorbed, the object appears violet or 
 purple. Thus, by the rate of the disturbing influence, and the 
 different combinations of these three colors, are all the various 
 shades in nature produced. 
 
 Relation of Colors to the Fabric— Although these re- 
 marks go to prove that color has no material existence in the 
 body appearing colored, still the question is one of chemical 
 science. As every chemical change affects the character of the 
 substance in its relations to light, the dyer's object is to effect 
 a combination with his stuffs that will produce certain effects 
 upon light, and thereby produce colors. It is found, sometimes, 
 that the nature of the fabric affects the beauty and tint of a 
 color. A chemical compound alone may be obtained that vies 
 with nature, both in the beauty and brilliancy of its color; 
 but, when that is obtained within the fibre of silk, cotton, or 
 wool, the light must be transmitted through the material as a 
 medium, and the fibre not being transparent, the original beauty 
 of the color is much diminished. Hence the same color, fixed 
 
EFFECTS OF DIFFERENT RAYS UPON COLORS. 
 
 27 
 
 within the fibres of those three substances, has different ap- 
 pearances in each ; the cotton never yields the beauty of color 
 that the silk does, or even the wool. These circumstances, in 
 all their relations, afford matter of constant study to the prac- 
 tical dyer. 
 
 It may be said that we cannot follow nature in the production 
 of colors — that were the dyer to attempt to produce a white by 
 an exact admixture of blue, red, and yellow, he would fail, and 
 would produce instead a black, or deep brown ; but this would 
 not be a proper application of the law above stated. Never- 
 theless, to a certain extent, the practice of producing white by 
 the combining of the three colors, is had recourse to every day 
 by the practical bleacher and dyer. All goods coming from 
 the bleaching process, no matter what the nature of the process 
 has been, have always a brownish yellow tinge: to cotton goods, 
 a little indigo or cobalt blue is added, and the result is, a much 
 purer white; to silk, which has much more of the yellow tinge 
 than cotton, a little Prussian blue and cochineal pink, or what 
 is more common, a little archil, which gives a violet color, is 
 added, the quantity varying according to the depth of yellow 
 — the result is a beautiful white. 
 
 The following simple experiment serves to illustrate how 
 far the production of colors depends upon the relation of the 
 substance to light: Take a solution of iodide of potassium, 
 which is colorless and transparent, and divide it into three pro- 
 portions; into the one pour a little acetate of lead (sugar of 
 lead), into the other a persalt of mercury, and into the third a 
 little starch, with a few drops of nitric acid. These are all 
 colorless substances; but after they are mixed, in the first we 
 have a deep and beautiful yellow ; in the second a red ; and in 
 the third a blue. Thus we have the three primitive colors 
 produced by the same substance combining with other sub- 
 stances, all previously colorless. Many white flowers, when 
 macerated in water, yield a yellow color, which alkalies turn 
 green and acids red. 
 
 Effects of different Eays upon Colors. — The three 
 separate rays of light have peculiarities of action : one has heat- 
 ing power, and is therefore termed the calorific ray ; another 
 has more of the property of giving light, and is termed the 
 luminous ray ; and the third has the greatest effect in changing 
 the composition of bodies, and is in consequence termed the 
 chemical ray. But, in our remarks upon the effects produced 
 by light, we will speak of their total action. 
 
 The effects of heat upon dyed colors, which we have already 
 described, are equally applicable to light, the presence of mois- 
 ture greatly facilitating the effects. Eeds, dyed by Brazil- 
 
28 EFFECTS OF LIGHT CAUSING COMBINATION. 
 
 wood and a tin mordant, exposed to light, pass into a brownish 
 orange, and then gradually fade away. Prussian blue becomes 
 reddish, and passes into a dirty gray. Yellows become brown, 
 and then fade. The effects of light and moisture are beautifully 
 shown by taking a piece of Prussian blue dry, and another 
 wet, and placing each under a glass, exposed to the rays of the 
 sun for a day. The wet piece becomes a reddish lavender, 
 while the dry piece is very little affected. Safflower colors 
 are easily affected by light, but more so when wet; so that 
 when such colors are being dried in the air, care should be 
 taken to keep them from exposure to light. 
 
 The action of light upon different matters and colors, and 
 its power of changing the constitution of these substances, 
 have recently formed the subject of a distinct branch of che- 
 mical study, known by the name of actino chemistry. Mr. Eobert 
 Hunt, who has done a good deal in this department of chemi- 
 cal science, says: "The changes produced by the influence of 
 the solar rays are of a remarkable character, and few of them, 
 in the present state of our knowledge, can be satisfactorily 
 explained. In some instances it would appear that new pro- 
 perties are imparted to bodies by exposure to sunshine ; in 
 others that radiation has the power of disturbing the known 
 chemical forces, and apparently establishing a new order of 
 affinities; whilst, in all, we are forced to recognize the opera- 
 tions of a principle, the nature of which is involved in the 
 most perplexing uncertainty." 
 
 Effects of Light causing Combination. — We will here 
 refer to a few examples of the action of light upon substances, 
 and the power it possesses of inducing changes, with a view to 
 impress upon the practical man the necessity of a strict atten- 
 tion to all the conditions and circumstances in which he may 
 have to place his colored fabrics and coloring materials. In 
 many cases bodies remain mixed and without action upon each 
 other in the dark, but combine rapidly and form new com- 
 pounds when exposed to light. Thus, chlorine and hydrogen 
 may be kept mixed in the dark for any length of time; but, if 
 exposed to daylight, they silently combine and form muriatic 
 acid. If the mixture be exposed to strong sunshine, the com- 
 bination becomes so rapid as to cause an explosion. 
 
 Chlorine, in water, remains a long time unaltered in the dark, 
 but by exposure to light the water is decomposed, muriatic acid 
 is formed, and oxygen given off. These effects are observed 
 daily in the operations of bleaching. If gray goods are put 
 into the bleaching liquor, and kept in the dark, they whiten 
 much more slowly than when exposed to light. Many bleachers 
 
LIGHT DECOMPOSES CHEMICAL COMPOUNDS. 
 
 29 
 
 know this, and expose their goods to light, and keep their 
 bleaching vessels in the lightest part of the premises. 
 
 Mixtures of chlorine with carbonic oxide, of chlorine with 
 sulphurous acid, and chlorine with pyroxylic spirit, and many 
 other substances, are similar examples of the same kind, being 
 all inactive upon each other in the dark, but combining easily 
 and rapidly when exposed to light. 
 
 Light decomposes Chemical Compounds.— Chemical com- 
 pounds are also decomposed by exposure to light. Carbonic 
 acid gas, exposed to strong sunshine, is decomposed into oxygen 
 and carbon. This decomposition is supposed to go on daily in 
 vegetable bodies during their growth, causing them to give off 
 oxygen and take up carbon. Colorless nitric acid, exposed to 
 the sun, soon becomes yellowish-brown, from a portion of it 
 being decomposed, and the red nitrous fumes remaining in the 
 acid produce the color — which again shows the propriety of 
 keeping the carboys with that acid in the shade as much as pos- 
 sible, as such changes by the sun's rays materially affect the 
 preparation of many of the dying compounds, and also the 
 strength of the acid. 
 
 Nitrate and chloride of silver, both white salts, become black 
 by exposure to light; paper or cloth saturated with these salts, 
 and exposed to light, is dyed permanently black. This is the 
 principle of the art of photography, which consists in expos- 
 ing a piece of paper saturated with such salts, with a leaf or 
 picture interposed between the light and the paper; an impres- 
 sion of the leaf or picture is thus obtained; and, by washing 
 the paper afterwards in a solution of hyposulphite of soda, or 
 weak ammonia, all the silver not affected or decomposed by 
 the light is dissolved and removed, and the picture thus fixed. 
 A piece of paper prepared with a solution of silver, and exposed 
 to the colored rays passing through a prism as described (page 
 25) is affected thus: — 
 
 Names of colored ray. Changes on paper prepared. 
 
 Violet Purplish black. 
 
 Indigo Black not so purplish. 
 
 These results are exceedingly curious and interesting, and 
 may point out some useful application in respect to the pre- 
 serving of compounds from change, by keeping them in vessels 
 which admit those rays only which least affect them. 
 
 Blue . 
 Green 
 Yellow 
 Orange 
 
 Eed 
 
 Black. 
 Green. 
 Eed. 
 
 Faint brick red. 
 No change. 
 
30 PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 Bichromate of potash put upon cotton fibre becomes dark 
 brown by exposure to light. 
 
 Chromate of copper, a brown substance, passes into white 
 by exposure to the sun's rays. 
 
 Solutions of substances are also affected by the sun's rays, 
 sometimes sufficiently to cause a precipitation. A solution of 
 protosulphate of iron (copperas) in distilled water, may be kept 
 a long time clear in the dark; but, when exposed to sunshine, 
 it becomes cloudy, and oxide of iron precipitates. A solution 
 of bichromate of potash, exposed to the sun's rays, acquires a 
 property of precipitating many metals, as chromates, much 
 darker than will be produced by a similar solution kept in the 
 dark. The reddening and darkening of chrome colors, by ex- 
 posure to light, is well known to dyers. The great effects of 
 light upon precipitates are well known to the manufacturers of 
 lakes — which, let it be borne in mind, are simply the coloring 
 matter which constitutes the dyes, precipitated and dried — and 
 therefore the effect produced upon these precipitates is equally 
 true of the same colors as dyes. Sir H. Davy gives the fol- 
 lowing anecdote of a maker of carmine, a lake made from 
 cochineal : — 
 
 "A manufacturer of carmine, who was aware of the supe- 
 riority of the French color, went to Lyons for the purpose of 
 improving his process, and bargained with the most celebrated 
 manufacturer in that city for the acquisition of his secret, for 
 which he was to pay £1000. He was shown all the process, 
 and saw a most beautiful color produced, but he found not "the 
 least difference in the French mode of fabrication and that 
 which had been constantly adopted by himself. He appealed 
 to his instructor, and insisted that he must have kept some- 
 thing concealed. The man assured him he had not, and invited 
 him to inspect the process a second time. He minutely exa- 
 mined the water and the materials, which were in every respect 
 similar to his own; and then, very much surprised, said: 'I have 
 lost both my labor and my money, for the air of England does 
 not admit us to make good carmine.' 4 Stay,' said the French- 
 man, 1 don't deceive yourself; what kind of weather is it now?' 
 'A bright sunny day, 7 replied the Englishman. 'And such are 
 the days,' said the Frenchman, 4 on which I make ray color ; 
 were I to attempt to manufacture it on a dark and cloudy day, 
 my results would be the same as yours. Let me advise you, 
 my friend, only to make your carmine on bright sunny days.'" 
 
 Practical Application of the Principles. — In the ap- 
 plication of some of these phenomena to the trade, we must 
 pause and inquire experimentally how this can be effected. 
 For instance, if we dissolve a piece of iron in nitric acid, and 
 
PRACTICAL APPLICATION" OF THE PRINCIPLES. 
 
 expose a portion of this solution for some time for the rays of 
 the sun, and keep the other portion in the dark, on adding a 
 solution of prussiate of potash to each of these, the precipitate, 
 formed by the portion exposed to light will be much deeper in 
 color than that kept in the dark. Were we to reason directly 
 from the result, we would expose our nitrate of iron solutions 
 to the light, in order to have a deeper dye; but if we test this 
 by experiment, and dye a piece with each of the iron solutions, 
 it will be found that the darkest blue is obtained from the iron 
 solution kept in the dark. Thus, we observe, without experi- 
 ment we may be liable to reason falsely. The change effected 
 upon the iron by the light may make it less fit to enter within 
 the pores or cells of the fibre; or if the combination of the stuff* 
 and fibre be affinity, these relations are affected ; which we will 
 discuss more fully in another part of this work. 
 
 These brief notices of the more prominent effects of light 
 upon colors, and other compounds, will serve to impress the 
 dyer with the importance of attending to what he too often 
 considers trifling circumstances; and to show that while every 
 different condition — the moisture of the air, the temperature, 
 the degree of light, &c, are all acting and reacting upon the 
 substances composing his colors, both before and after they are 
 fixed upon the fabric, nothing should be considered too trifling 
 or of too little consequence to warrant its being overlooked. 
 
 The consideration of the chemical changes which are sup- 
 posed to be taking place in the vegetable kingdom through the 
 influence of light, will be more fully explained when we are 
 treating of the coloring matters of vegetables. 
 
 In connection with light, there is an application of a very 
 important practical kind which it will be well to notice, namely, 
 the arrangement of colors, so that their harmony should pro- 
 duce the best effect. Upon this subject many propositions were 
 made for the decoration and laying out the manufactures in the 
 Great Exhibition. Upon the philosophy of the arrangement 
 of different colors for effect, we will quote from the Athenceum 
 (Athen. 1851, p. 273) a few passages upon this subject, which 
 we think will be useful to the dyer: — 
 
 "The Successive' contrast has long been known ; and it con- 
 sists in the fact, that if, you look steadfastly for a few minutes 
 on a red surface fixed on a white sheet of paper, and then carry 
 your eye to another white sheet, you will perceive on it not a 
 red but a green one; if a green, red; if purple, yellow; if blue, 
 orange. The 1 simultaneous' contrast is the most interesting 
 and useful to be acquainted with. When two colored surfaces 
 are in juxtaposition, they mutually influence each other — favor- 
 ably, if harmonizing colors, or in a contrary manner if discord- 
 
32 
 
 PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 ant; and in such proportion in either case as to be in exact ratio 
 with the quantity of complementary color which is generated 
 in our eye. For example, if two half-sheets of plain tint-paper 
 — one dark green, the other red — are placed side by side on a 
 gray piece of cloth, the colors will mutually improve, in conse- 
 quence of the green generated by the red surface adding itself 
 to the green of the juxtaposed surface — thus increasing its in- 
 tensity — the green in its turn augmenting the beauty of the 
 red. This effect can easily be appreciated, if two other pieces 
 of paper of the same colors are placed at a short distance from 
 their corresponding influenced ones, as below: — 
 
 RED. RED GREEN. GREEN. 
 
 It is not sufficient to place complementary colors side by side 
 to produce harmony of color, the respective intensities having 
 a most decided influence ; thus pink and light green agree— 
 red and dark green also; but light green and dark red, pink 
 and dark green do not; therefore, to obtain the maximum of 
 effect and perfect harmony, the following colors must be placed 
 side by side, taking into account their exact intensity of shade 
 and tint: — 
 
 HARMONIZING COLORS. 
 
 Primitive Colors. Secondary Colors. 
 
 r Light Blue. 
 
 Eed Green . . . . < Yellow. 
 
 (Red. 
 ( Red. 
 
 Blue Orange . . . < Yellow. 
 
 (Blue, 
 f Blue. 
 
 Yellow orange . . . Indigo . . . < Red. 
 
 (Yellow. 
 TRed. 
 
 Greenish yellow . . Violet. . . . < Blue. 
 
 (Yellow. 
 (Yellow. 
 
 Black White . . . < Blue. 
 
 (Red. 
 
 u If respect is not paid to the arrangement of colors according 
 to the above diagram, instead of colors mutually improving 
 each other, they will, on the contrary, lose in beauty: thus, if 
 blue and purple are placed side by side, the blue throwing its 
 complementary color, orange, upon the purple, will give it a 
 faded appearance; and the blue receiving the orange-yellow of 
 the purple, will assume a greenish tinge. The same may be 
 
PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 said of yellow and red, if placed in juxtaposition. The red, 
 by throwing its complementary color, green, on the yellow, 
 communicates to it a greenish tinge; the yellow, by throwing 
 its purple hue, imparts to the red a disagreeable purple appear- 
 ance. It is of very great importance that every one should be 
 acquainted with the laws of colors who intends to display or 
 arrange colored goods or fabrics. 
 
 "The mixed contrast gives the reason why a brilliant color 
 should never be looked at for any length of time if its true 
 tint or brilliancy is to be appreciated ; for if a person looks, 
 for example, at a piece of red cloth for a few minutes, green, 
 its, complementary color, is generated in the eye, and adding 
 itself to a portion of the red, produces black, which tarnishes 
 the beauty of the red. This contrast explains why the shade 
 of a color may be modified according to the color which the 
 eye has previously looked at, either favorably or otherwise. 
 An example of the first instance is noticed when the eye first 
 looks to a yellow substance and then to a purple one; and as 
 exemplifying the second case, looking at a blue and then at a 
 purple." 
 
 3 
 
34 
 
 ELEMENTS OF MATTER. 
 
 I 
 
 Differences between an Element and Compound. — It 
 has been intimated that the conditions of matter — solidity, 
 fluidity and gasuity — depend upon heat; and it was also stated 
 that, in each state, there is a vast variety — a variety so great 
 that the idea of telling where their conditions begin and end 
 is a task seemingly beyond human power. Nevertheless, by 
 labor, by experiment, and comparison, much has been done 
 not only to distinguish every variety of substance, but why 
 one substance differs from another both in appearance and 
 quality. Let us take a known compound as an illustration: 
 When a piece of steel is placed into diluted sulphuric acid, 
 the acid dissolves the greater part of it; but there is left un- 
 dissolved a black matter, which, by testing, we find to be char- 
 coal or carbon, and that which has been dissolved is iron. We 
 therefore infer that steel is composed of iron and charcoal — 
 that it is a compound substance; but if we take the carbon, 
 and treat it in any way within our power, we find it still the 
 same, without components. In the same manner let us test 
 iron — dissolve it, melt it, or treat it as we will, it yields nothing 
 but iron. All such substances, then, that resist every effort to 
 decompose, or show any admixture, are termed elementary ; or 
 simple substances. The number of such elements known to 
 the chemist at the present time are sixty two, and all the varie- 
 ties in which we find matter presenting itself to us — whether in 
 the mineral, the vegetable, or the animal kingdom — are made 
 up of one, or a mixture of two or more of those sixty-two ele- 
 ments. The following table gives the names and particulars 
 necessary to be observed in the study of these elements : — 
 
 Aluminum . 
 
 . Al 
 
 
 13.7 
 
 Carbon . . 
 
 . C 
 
 
 6 
 
 Antimony . 
 
 . Sb 
 
 
 129 
 
 Cerium . . 
 
 . Ce 
 
 
 47 
 
 Arsenic . . 
 
 . As 
 
 
 75 
 
 Chlorine 
 
 . CI 
 
 
 35.5 
 
 Barium . . 
 
 . Ba 
 
 
 68.5 
 
 Chromium . 
 
 . Cr 
 
 
 26.2 
 
 Beryllium . 
 
 . Be 
 
 
 4.7 
 
 Cobalt . . 
 
 . Co 
 
 
 29.5 
 
 Bismuth 
 
 . Bi 
 
 
 213 
 
 Copper . . 
 
 . Cu 
 
 
 31.7 
 
 Boron . . 
 
 . B 
 
 
 11 
 
 Didymium . 
 
 . D 
 
 
 
 Bromine 
 
 . Br 
 
 
 80 
 
 Erbium . . 
 
 . E 
 
 
 
 Cadmium . 
 
 . Cd 
 
 
 56 
 
 Fluorine 
 
 . Fl 
 
 
 19. 
 
 Calcium . . 
 
 . Ca 
 
 
 20 
 
 Gold . . . 
 
 . Au 
 
 
 197 
 
DIFFERENCES OF AN ELEMENT AND COMPOUND. 35 
 
 Hydrogen . 
 
 . H 
 
 
 
 1 
 
 Rhodium . 
 
 . R 
 
 
 52.2 
 
 Iodine . 
 
 . I 
 
 
 
 127 
 
 Ruthenium 
 
 . Ru 
 
 
 
 52.2 
 
 Iridium . . 
 
 . Tr 
 
 — 
 
 99 
 
 Selenium . 
 
 . Se 
 
 
 
 39.5 
 
 Iron . 
 
 . Fe 
 
 — 
 
 28 
 
 Silicium 
 
 . Si 
 
 
 
 21.3 
 
 Lanthaniurn 
 
 . La 
 
 
 
 Silver . . 
 
 . Ag 
 
 o 
 
 
 108.1 
 
 Lead . . . 
 
 . Ph 
 
 
 
 103.6 
 
 Sodium . . 
 
 . Na 
 
 
 
 23 
 
 Lithium . 
 
 . Li 
 
 
 
 6.5 
 
 Strontium . 
 
 . Sr 
 
 
 
 43.8 
 
 Magnesium 
 Manganese . 
 
 • Mg 
 
 
 
 12 
 
 Sulphur. . 
 
 . S 
 
 
 
 16 
 
 . Mn 
 
 b= 
 
 27.6 
 
 Tantalum . 
 
 . Ta 
 
 
 
 184 
 
 Mercury 
 
 • Hg 
 
 B 
 
 100 
 
 Tellurium . 
 
 . Te 
 
 
 
 64.2 
 
 Molybdenum 
 
 . Mo 
 
 BS 
 
 46 
 
 Terbium 
 
 . Tb 
 
 
 
 Nickel . . 
 
 . Ni 
 
 BS 
 
 29.6 
 
 Thallium . 
 
 . Tl 
 
 
 
 Niobium . 
 
 . Nb 
 
 
 
 Thorium 
 
 . Th 
 
 
 
 59.6 
 
 Nitrogen 
 
 . N 
 
 
 14 
 
 Tin . . . 
 
 . Sn 
 
 
 
 59 
 
 Osmium 
 
 . Os 
 
 
 
 99.6 
 
 Titanium . 
 
 . Ti 
 
 
 25 
 
 Oxygen . . 
 
 . 0 
 
 as 
 
 8 
 
 Tungsten . 
 
 . W 
 
 
 92 
 
 Palladium . 
 
 . Pd 
 
 
 53.3 
 
 Uranium 
 
 . U 
 
 
 60 
 
 Pelopium . 
 
 . Pe 
 
 
 
 Yanadium . 
 
 . V 
 
 
 68.6 
 
 Phosphorus 
 
 . P 
 
 
 32 
 
 Yttrium . . 
 
 . Y 
 
 
 32.2 
 
 Platinum . 
 
 . Pt 
 
 
 98.7 
 
 Zinc . . . 
 
 . Zn 
 
 
 32.6 
 
 Potassium . 
 
 . K 
 
 
 39.2 
 
 Zirconium . 
 
 . Zr 
 
 
 22.4 
 
 When two or more of these elements combine together, it 
 is found that the union does not take place indeterminately, 
 but always in definite proportions. These proportions are ex- 
 pressed by the figures placed opposite to the names in the 
 above table. For example, if we mix together one ounce of 
 hydrogen and one ounce of oxygen, and bring them under 
 circumstances to cause combination, it is found that the one 
 ounce of oxygen has combined with an eighth part of the 
 hydrogen, or two drachms, and that other seven ounces of 
 oxygen are required to combine with the whole of the hydro- 
 gen. Their combining properties are therefore set down as 1 
 to 8. The same law holds good for every other element ; so 
 that the union is invariably distinct and definite. One ele- 
 ment, however, is often found to combine with another in a 
 greater number of proportions than one to one. Thus, sup- 
 pose nitrogen — which, according to the table, has a combin- 
 ing weight of 14 — combines with oxygen in proportions as 
 under : — 
 
 One nitrogen = 14 to one oxygen == 8. 
 One nitrogen = 14 to two oxygen = 16 two times 8. 
 One nitrogen = 14 to three oxygen = 24 three times 8. 
 One nitrogen = 14 to four oxygen = 32 four times 8. 
 One nitrogen = 14 to five oxygen = 40 five times 8. 
 
 Thus we observe that the proportion of oxygen is always 8, or 
 
36 
 
 USE OF SYMBOLS. 
 
 a multiple of 8 ; so it is with nitrogen, always 14, or twice 14, 
 and so on to any number of multiples of 14. ■ The same rule 
 holds good with every element in the table ; they combine only 
 according to the number following the name. 
 
 But when they thus combine in different and distinct quan- 
 tities, the compounds formed are also distinct and definite. 
 Thus, one portion of nitrogen and one oxygen is laughing gas ; 
 and it is so at all times and under all circumstances, and can 
 be nothing else. But when two of oxygen combine to one of 
 nitrogen, a different substance is formed from laughing gas, 
 also distinct and definite from every other proportion in which 
 the elements unite. The first and last of the above list is an 
 apt illustration — the former being laughing gas, the latter 
 aquafortis — nitric acid. 
 
 Use of Symbols. — The letters placed immediately after the 
 names of the elements in the above table, are the symbols com- 
 monly used to represent the respective elements, and facilitate 
 the expression of the compounds into which they enter. 
 Thus, to represent laughing gas, we write NO, which means 
 one of nitrogen and one of oxygen. The symbol always repre- 
 sents the weight of the proportion, as given in the table; and 
 the figures attached show how often that proportion is re- 
 peated. Thus, the formula for aquafortis, N0 5 , which means 
 one part of nitrogen and five of oxygen — the figure being 
 placed immediately after the symbol which is multiplied. 
 Were there two of nitrogen and one of oxygen, the formula 
 would be N 2 0; but sometimes there may be two or more pro- 
 portions of a compound combined with another compound ; 
 this is represented by placing the figure before the compound 
 to be multiplied, and a comma at the end. For example — two 
 proportions of aquafortis united with one of water is expressed 
 thus, 2N0 5 , HO. The figure 2 applies to all between it and 
 the comma. Some use the sign + instead of a coma — thus, 
 2N0 5 + HO. It being important to the student that these be 
 fully understood before beginning to read for study, we will 
 take another series of compounds : — 
 
 S0 3 one sulphur, three oxygen, sulphuric acid. 
 
 S0 3 +HO sulphuric acid with one water. 
 
 2SO3+HO two sulphuric acid with one water. 
 
 SO3 + 2HO sulphuric acid and two water. 
 
 S0 3 +-3HO sulphuric acid and three water. 
 
 S0 3 + FeO or S0 3 , FeO sulphuric acid and oxide of iron. 
 
 S0 3 FeO + HO sulphuric acid, oxide of iron, and water. 
 
 S0 3 FeO + 5HO sulphuric acid, oxide of iron, and five water. 
 
 8SO3, Fe 2 0 3 + 9HO, here we have three of sulphuric acid, 
 
CHEMICAL NOMENCLATURE. 
 
 37 
 
 two of iron, three of oxygen, and nine water, which is the 
 formula of one of the salts of iron. 
 
 To make up the equivalent weight of any compound from 
 symbols, we have simply to multiply the elements given ac- 
 cording to the table. Thus, suppose we take the sulphuric 
 acid and two water, which is strong vitriol, we have 
 
 One sulphur equivalent weight, 16 = 16 
 
 Three oxygen 8x3 = 24 
 
 Two water ... 1 hy. and 8 oxygen ... =9x2 = 18 
 
 58 
 
 which is the proportion or weight of sulphuric acid of the 
 strength which would be required to combine with any other 
 element, suppose iron, which is 28; therefore it would require 
 fully twice the weight of sulphuric acid of this strength to 
 that of a piece of iron to dissolve it. 
 
 The following formula of crystallized alum will serve as an 
 exercise for the student upon the symbols and equivalents : — 
 
 KOS0 3 , A1 2 0 3 3S0 3 + 24HO. 
 
 Some chemists, instead of using 0 for oxygen, express it by a 
 
 simple . — thus sulphuric acid will be S, or the alum — 
 
 KS Al 2 3S 24H. 
 
 Nomenclature. — In the nomenclature of these elements in 
 the above table there has been no definite rule, being named 
 either from the fancy of the discoverer, or from some leading 
 property or appearance they present, which will be noticed un- 
 der their separate descriptions; but, in naming compounds, a 
 distinct rule has been adopted, so that the name of the com- 
 pound expresses, as nearly as possible, its composition and pro- 
 perty. We will give a few of the leading principles observed 
 in this rule of naming compounds. 
 
 Rules for Naming Compounds. — When two elements com- 
 bine together, and the compound formed has not acid properties, 
 the name ends in ide, such as oxide, chloride, bromide, iodide, &c. 
 Sometimes uret is used instead of ide,. such as in sulphuret, car- 
 buret, phosphuret, &c. ; but ide is now most generally adopted 
 even for these, giving sulphides, carbonides, phosphides, &c. When 
 the compound formed by the union of the elements has acid 
 properties, the name ends in ic, or ous ; thus we have sulphuric, 
 sulphurous, nitric, nitrous, chloric, and chlorous acids ; but these 
 elements, uniting together in different multiples, have prefixes 
 added to express the number of proportions. Thus, proto de- 
 
38 
 
 CHEMICAL NOMENCLATURE. 
 
 notes one proportion, or first; devto, or bi, two proportions; 
 trito, three proportions ; per denotes no particular number only 
 the highest proportion. As examples, take the compounds 
 of hydrogen and nitrogen, already noticed : — 
 
 NO protoxide of nitrogen. 
 N0 2 binoxide of nitrogen. 
 N0 3 nitrous acid. 
 N0 4 peroxide of nitrogen. 
 NO,, nitric acid. 
 
 Thus, we observe, the full name of the substance not having 
 acid properties denotes its composition. In the case of acids, 
 it does not tell the number of elements combined, as with ox- 
 ides — ous simply signifying that it has less oxygen than another 
 acid composed of the same elements, and which ends in ic. 
 There are sometimes more than two acids formed by the com- 
 bining of the same elements ; in this case, if the oxygen is less 
 than in the acid whose name terminates with ous, the prefix 
 hypo is put to the name of the ous acid; if there be more oxygen 
 than in the ous acid, and less than the ic acid, the same prefix is 
 made to the last-named acid. Finally, when there is more oxy- 
 gen present than in the acid whose name terminates with ic, 
 the prefix per is put as in oxides. The following illustrations 
 will exemplify these terms. 
 
 S 2 0 2 hypo-sulphurous acid. 
 S0 2 sulphurous acid. 
 S 2 0 5 hypo-sulphuric acid. 
 S0 3 sulphuric acid. 
 
 Any acid found having more oxygen, in relation to the sul- 
 phur, than the last named in this list, would be called ^er-sul- 
 phuric acid. It will thus be seen that the names of the compounds 
 denote their composition, and give an idea of their leading pro- 
 perties. The term sesqui — as sesquioxide — is often used, and 
 means one and half of an equivalent, which, as may be inferred 
 from what has been said, cannot take place. Nevertheless, the 
 name is conveniently retained to denote such compounds as 
 have two of one element and three of another — such as ses- „ 
 quioxide of iron, also termed peroxide, and which is com- 
 posed of two iron with three oxygen, Fe 2 0 3 . Sometimes one 
 proportion of oxygen, chlorine, &c, combines with two propor- 
 tions of a base as a metal; such compounds have the prefix 
 sub, or di as 
 
 Fe 2 0, sub-oxide of iron, or dinoxide of iron. 
 Cu 2 Cl, sub-chloride, or dichloride of copper. 
 
CHEMICAL NOMENCLATURE. 
 
 89 
 
 When one proportion of oxygen, chlorine, &c, combines with 
 three of a metal, the prefix trisub or tridi, is occasionally used, 
 but this is not very convenient; the best and most general plan 
 is to-denote such compounds as basic, and then apply the ordi- 
 nary prefixes, such as bibasic, tribasic, &c, thus: — 
 
 Cu 2 0, bibasic oxide of copper. 
 Cu 3 0, tribasic oxide of copper. 
 
 In the name of a compound ending in ide, the base or element 
 with which the oxygen, chlorine, &c, is combined, is named 
 last, as 
 
 * Oxide of iron. Oxygen and iron. 
 
 Chloride of iron. Chlorine and iron. 
 
 Iodide of iron. Iodine and iron. 
 
 Oxide of sulphur. Oxygen and sulphur. 
 
 Oxide of nitrogen. Oxygen and nitrogen. 
 
 But with compounds having acid properties, the base is placed 
 at the beginning, thus: — 
 
 Sulphuric acid. Sulphur and oxygen. 
 
 Nitric acid. Nitrogen and oxygen. 
 
 Hydrochloric acid. Hydrogen and chlorine. 
 
 Salts— Their Nature and Nomenclature. — The acids 
 combine with other substances, as the metals, and form another 
 *class of compounds termed Salts. The names of these also 
 denote their composition: the salt formed between the acid ter- 
 minating in ic and a base, ends with ate; that formed by the 
 acid terminating in ous ends with ite, the name of the element 
 with which the acid combines being added. Thus, 
 
 Sulphuric acid and iron form sulphate of iron. 
 Sulphurous acid and iron . . sulphite of iron. 
 
 When these acids unite with elements or bases in different pro- 
 portions, the same prefixes are used as with oxides. If one 
 proportion of acid unites with one of another element, the com- 
 pound is termed proto — as proto-sulphate of iron; if two of acid 
 and one metal, the compound has bi — as bisulphate of iron, &c. 
 Per is also used as denoting the highest proportion, as when 
 three equivalents of acid unite with two equivalents of iron, 
 the salt is termed persulphate of iron. 
 
 Sometimes we have the metal uniting with acids, forming 
 basic salts, as described in the case of the basic oxides, such as 
 having two proportions of metal to one of acid, and three pro- 
 portions or equivalents of metal to one of acid. In such cases, 
 the same prefixes are used as we have before stated, namely — 
 
40 
 
 CHEMICAL NOMENCLATURE. 
 
 hibasic sulphate of copper, two equivalents of copper to one 
 of sulphuric acid ; tribasic sulphate of copper, three of copper 
 to one of acid. 
 
 Combinations of water with oxides or salts are termed hy- 
 drates, or the compound is termed hydrous, in contradistinction 
 to substances having no water, which are termed anhydrous — 
 thus, hydrate of potash, or hydrous potash, KO HO ; anhy- 
 drous potash, KO. 
 
 Two salts sometimes unite together, and form a definite 
 compound, which is termed a double salt. Alum, as already 
 given, is a good instance of this class of compounds: it is a 
 double salt of sulphate of alumina and sulphate of potash. 
 
41 
 
 CHEMICAL AFFINITY. 
 
 The elements of matter have a disposition, if we may use 
 the term, to unite with one another ; this disposition is termed 
 affinity, or chemical attraction. The affinity of any one ele- 
 ment for the others is not equal, but is greater for some one 
 element, or for a particular class of elements. Thus oxygen 
 has a stronger attraction for those elements, the combining of 
 which forms alkalies, than for any of the others; and amongst 
 these potassium has the strongest affinity for oxygen; so that, 
 by the operation of this law, should a number of elements be 
 arranged together, under proper circumstances for combining, 
 those which have the strongest attraction for each other will 
 combine first. The same law holds good when compound 
 bodies unite together, such as an acid with the oxide of a metal. 
 Were we to take sulphuric acid, and add to it a mixture 
 of potash and magnesia, the acid would combine with the 
 potash before it would take the magnesia; and were there 
 enough of potash to combine with the whole of the sulphuric 
 acid, the magnesia would be left, because the potash has a 
 stronger attraction for this acid than magnesia. This pecu- 
 liarity of selecting is not merely owing to the substance having 
 acid properties, but from a peculiar attraction between the 
 base and acid compounds. Thus the two acids, sulphuric and 
 muriatic, comport themselves towards the following bases, as 
 under : — 
 
 Muriatic Acid. 
 Silver, 
 Potash, 
 Soda, 
 Barytes, 
 Strontia, 
 Lime, 
 Magnesia. 
 
 Although we have named silver here, under the sulphuric 
 acid column, in order to complete the comparison, it is not 
 immediately next to magnesia in affinity for that acid; a great 
 many of the other metals rank before it, such as mercury, 
 iron, zinc. So that, were there a solution of sulphate 
 
 Sulphuric Acid. 
 Barytes, 
 Strontia, 
 Potash, 
 Soda, 
 Lime, 
 Magnesia, 
 Silver. 
 
42 
 
 CIRCUMSTANCES INFLUENCING AFFINITY. 
 
 of silver added to a solution containing these, the acid would 
 leave the silver and combine with the mercury, next leave the 
 mercury and combine with copper, then leave the copper and 
 take the iron, and lastly, leave the iron and take the zinc. 
 
 It is this law of affinity that regulates compositions and de- 
 compositions, all of which are matters of daily experience in 
 the dye-house, particularly that class of decompositions termed 
 double, in which two salts being put together, there takes place 
 a mutual exchange of partners, if we may so term it. For 
 instance, in mixing nitrate of iron with yellow prussiate of 
 potash : the nitric acid leaves the iron, and combines with the 
 potash, while the iron and prussic acid combine, forming 
 Prussian blue. When any of the two compounds so combined 
 forms an insoluble substance, the decomposition is always more 
 apparent, more complete, and most applicable to dyeing pur- 
 poses. Compounds which cannot easily be formed, directly by 
 bringing their elements together, are often formed by means 
 of double decomposition : thus carbonate of iron is difficult to 
 form directly, but by mixing a solution of carbonate of soda 
 with sulphate of iron, this compound is instantly formed, 
 which may be thus represented : — 
 
 NaO C0 2 , FeO S0 3 = FeO C0 2 , NaO S0 3 . 
 
 Application of Affinity. — These double decompositions 
 and recompositions are of the utmost importance to the practi- 
 cal dyer, who should make himself thoroughly acquainted with 
 all their laws and conditions; as it is, these formations of new 
 and often insoluble compounds, which constitute a prominent 
 feature in the production of colors, and every circumstance 
 connected with this class of phenomena, favors this kind of re- 
 action for practical purposes. It is a general law in ordinary 
 affinity, in the union of two elements, or of a compound with 
 an element, such as dissolving a metal in acid, that there is 
 always a great evolution of heat. This circumstance w T ould 
 interfere with many dyeing operations, both upon the fibre and 
 color ; but in the double affinity referred to, where two com- 
 pounds merely exchange elements, there is no quantity of heat 
 evolved, to interfere with the dyeing operations or fabric. The 
 interchange of elements takes place quietly, so that the dyer 
 may fix within th'e fibres of the most delicate material any 
 compound required for the color. 
 
 Circumstances influencing Affinity. — The force of 
 affinity is greatly influenced by the conditions in which the 
 combining bodies are placed, as indicated when treating of 
 light and heat. Where the atoms of any body are brought into 
 contact with another body under more or less favorable circum- 
 
CATALYTIC INFLUENCE. 
 
 43 
 
 stances, anything that diminishes the cohesion of the particles, 
 allows those of the other body to come into closer approxima- 
 tion, and therefore favors chemical union. Solid bodies, in ge- 
 neral, are without chemical action upon one another; therefore, 
 before any chemical change can take place, it is necessary to 
 bring the substance into a fluid state. This is eminently ne- 
 cessary in all dyeing operations, not only for the purpose of 
 causing combination, but to enable the particles to enter within 
 the fibres of the cloth, and to be, while there, acted upon by the 
 affinity of another body, also in solution, brought into contact 
 with them. This is an essential condition of all dye drugs, 
 and of all salts used in dyeing, either as dyes or mordants, and 
 must never be lost sight of in studying either its philosophy 
 or practical operation ; as anything that interferes with the free 
 operation of these conditions or solubility, necessarily retards 
 the process or deteriorates the dye. 
 
 Catalytic Influence. — Another circumstance or power 
 sometimes occurring in dyeing operations, which interferes with 
 or directs chemical affinity amongst the particles of bodies, is, 
 that one body often induces a chemical change in another, 
 while it undergoes no change itself. This kind of affinity, or 
 power, is termed Catalysis. A good instance of this is in 
 fermentation ; a little yeast put into beer induces fermentation 
 in all the solution, while the yeast is not altered. If we boil 
 starch with dilute sulphuric acid, the starch is first changed 
 into gum, and then into sugar. Yet, notwithstanding these 
 changes, the sulphuric acid is found unaltered, either in pro- 
 perty or quantity. A great many substances possess this pro- 
 perty of catalytic influence; and it is not unlikely that fibrous 
 materials, such as silk, woollen, and cotton, possess it towards 
 many of the vegetable coloring matters used in dyeing; in- 
 deed, many operations in the dye-house indicate the presence 
 of some such power. The real nature of this power is not 
 well understood; only we know that bodies subject to change 
 by catalysis have their particles held together by a weak affi- 
 nity, and therefore changes are less or more easily effected, 
 according to the power exerted, to keep their elements together. 
 The elements of many organic compounds seem held together 
 by a balance of power among them, so that while another 
 substance put into such a compound may possess a sufficient 
 attraction for some of the elements in the compound, to disturb 
 this balance of power, yet it may not have sufficient power to 
 combine with them, but only cause the whole elements to 
 rearrange themselves in a new, and probably more stable, form. 
 The study of such reactions is of the greatest interest; and as 
 these principles of action, in all probability, play a prominent 
 
CONSTITUTION" OF SALTS. 
 
 part in the art of dyeing, it will be again brought under 
 consideration, when describing operations where we think this 
 action takes place. We may here mention, however, that the 
 introduction of such a term as catalysis is only considered 
 useful as bringing under one group a certain class of phe- 
 nomena ; but, indeed, the same may be said of the no less 
 useful term, affinity. When our knowledge of these hidden 
 powers is more extended, all those phenomena may, perhaps, 
 be accounted for, and ranged under the operation of some one 
 universal power or law, of which at present we know only by 
 particular terms. 
 
 Constitution of Salts. — It may have been observed that, 
 in describing the constitution of compounds and their nomen- 
 clature, we grouped the elements together, as compounds, in a 
 certain order, such as sulphate of protoxide of iron, FeO S0 3 . 
 This formula, by its term and grouping, it may be farther ob- 
 served, indicates that the sulphuric acid is combined with the 
 oxide of the iron, and not directly with the iron itself. Now 
 there is a difficulty which attaches to the nomenclature, that 
 the formula is made to indicate a certain definite arrangement 
 pf particles, which is now pretty generally considered as incor- 
 rect. However, it is not intended to enter here into the merits 
 of the different views entertained by chemists regarding this 
 point, but briefly to give a general idea as a guide to the work- 
 man. We will take sulphuric acid as our first illustration. 
 The composition of this acid is given S0 3 , but S0 3 is a solid 
 crystalline compound, which has no acid properties until it is 
 combined with one proportion of water, being then S0 3 + HO, 
 or hydrous sulphuric acid. If into this acid we place a piece 
 of iron, the reaction may be expressed thus: S0 3 HO + Fe= 
 S0 3 FeO + H; or as follows: — 
 
 Water . . . • |jj " Ns v Hydrogen Gas. 
 
 Here we have water decomposed, to give an atom of oxy- 
 gen to the iron, forming an oxide ; and then we have the acid 
 combining with this oxide. The same principle of action is 
 ascribed to all metals, and used to be described as a sort of 
 disposing affinity. The acid S0 3 is conceived to have such an 
 attraction for the oxide of the metal, that it disposes both the 
 metal to combine with oxygen and the oxygen with the metal, 
 in order that it might unite with the two, to form a salt. Sir 
 H. Davy, with his usual clear perception of all* chemical phe- 
 nomena, thought that, as sulphuric acid S0 3 had no acid pro- 
 
 Sulphuric Acid . S0 3 
 Iron .... Fe... 
 
 Protosulphate of Iron. 
 
SALT RADICALS. 
 
 45 
 
 perties, and was incapable of combining with any body as such, 
 except in union with water, it was more probable that what is 
 termed hydrated sulphuric acid S0 3 4- HO, may be the true 
 composition of sulphuric acid, rather than S0 3 , and ought to be 
 represented thus, S0 4 + H, the hydrogen being the base or metal, 
 and that its presence is an essential qualification to the acid : 
 so that a piece of iron, being put into sulphuric acid, will have 
 a reaction as under, S0 4 H4-Fe = S0 4 Fe + H: — 
 
 Sulphuric Acid -[ *~ Hydrogen Gas. 
 
 Iron .... Fe.. Sulphate of Iron. 
 
 Here we have no supposed primary-disposing action, but the 
 iron simply taking the place of hydrogen, by substitution, in 
 virtue of S0 4 , having a stronger affinity for it than for the 
 hydrogen. The same reaction explains the dissolving of any 
 other metal in sulphuric acid. Names have been proposed in 
 accordance with this theory, as, for instance, the S0 4 is termed 
 sulphion; therefore, S0 4 +H, instead of being termed sulphuric 
 acid, will be sulphionide of hydrogen, and sulphate of iron, sul- 
 phionide of iron. Such names will however, be very difficult 
 to be introduced into the science; and although they were 
 approved of, their use must necessarily be a matter of gradual 
 growth. As the truths of these views become apparent, a new 
 and improved nomenclature may grow up spontaneously. 
 
 The views given above, of the true formula of sulphuric 
 acid, may be applied to all hydrated acids. Nitric acid of the 
 formula N0 5 has never been isolated ; its existence is merely 
 supposed from analogy. There is N0 5 + HO, hydrated nitric 
 acid; but why N0 5 + HO, rather than N0 6 +H ? Any metals 
 dissolving in it only replace the hydrogen. The same with 
 muriatic acid which is a compound of hydrogen and chlorine, 
 properly termed hydrochloric acid. In dissolving a metal in 
 this acid, the acid, not the water, is decomposed. Or if we 
 put hydrochloric acid upon the oxide of a metal, as soda, the 
 action is not that of the acid combining with the oxide, but 
 there is a double decomposition and composition, represented 
 by HC1 HO + NaO = NaCl + 2HO. So that bodies termed 
 muriates are more properly chlorides. 
 
 Salt Radicals. — There is another thing necessary for the 
 student to bear in mind, in reference to these views, and the 
 nomenclature resting upon them. The S0 4 , N0 6 , &c, are 
 called the Salt Radicals, which term is often used in chemical 
 books, and is applied equally to a compound, such as the above, 
 or to an element, such as chlorine. It refers to any element, 
 or compound that will form an acid when combined with hydro- 
 
46 
 
 SALT RADICALS 
 
 gen, and a salt when united with a metal. There are a great 
 many salt radicals which are compound substances, but which 
 deport themselves in their reactions as elements. One emi- 
 nent example of a substance of this kind is cynogen, (C 2 N) 
 which is the salt radical of Prussic acid, and which we shall 
 have occasion to notice when treating of the compounds of 
 this acid and the ferro-prussiates, so much used in the dye- 
 house. 
 
 This view of the constitution of salts is much more simple 
 than that of oxides combining with the acids, and, as it will 
 be apparent, reduces the compound bodies, termed acids and 
 salts, into one great class. 
 
 It also enables us to account for a remarkable law which 
 has been already noticed, namely, that bases, such as metals, 
 always unite with the same number of proportions, or equiva- 
 lents of acids or salt radicals. Thus, if we dissolve protoxide 
 of iron in sulphuric acid, one proportion of iron only com- 
 bines with one proportion of acid, and is represented by FeO, 
 S0 4 H=Fe S0 4 , HO. 
 
 But if we take the peroxide of iron, and dissolve it in sul- 
 phuric acid, we have then three proportions of acid, thus — 
 
 Fe 2 0 3 , 3S0 4 H=Fe 2 3S0 4 HO. 
 
 It must, however, be borne in mind, that both theories re- 
 quire several hypothetical conditions to be taken for granted, 
 to enable us to account for all the phenomena which take place 
 in the actions of one body upon another; and also, that both 
 these views of the constitution of salts, as to the manner in 
 which the atoms or particles arrange themselves, are liable to 
 objections. We have stated the fundamental principles of 
 these views, both as a general guide to the student in his inqui- 
 ries into chemical science, and because we shall have occasion 
 to refer to them hereafter. But the reader who wishes to ob- 
 tain more extended information, may consult such works as 
 those of Graham, Liebig, Daniell, Gmelin, and others, who have 
 given this matter much close attention ; and such research will 
 be found amply to repay any labor and time expended upon it ; 
 for on the proper understanding of the fundamental laws of 
 affinity depends, in a great measure, the proper application of 
 chemical science to practical purposes, and more especially in 
 such delicate operations, and with such materials, as the animal 
 and vegetable fibres operated upon in a dye-house. 
 
ELEMENTARY SUBSTANCES. 
 
 Oxygen (0. 8.) 
 
 By referring to the table of elements, it will be found that 
 several substances are therein named which many of our prac- 
 tical readers have never heard of. There are, indeed, a num- 
 ber of elements of which little more is known than the fact of 
 their existing in certain compounds; they have only been seen 
 by the discoverers and a few friends, and are as yet so rare, 
 and found in such small quantities, that, under present circum- 
 stances, their application to any common branch of manufac- 
 ture is not thought of. Such substances we will therefore pass 
 over with a very short notice, and confine ourselves more to 
 those that are, or, so far as their cost and quantities are con- 
 cerned, may be brought into common use. The name of the 
 element at the head of this chapter is a very familiar term in 
 the dye-house, but is applied so indiscriminately, and so often 
 erroneously, to different substances, as to cause a considerable 
 misunderstanding of its real nature and properties. Many of 
 these erroneous applications of the name, and consequent con- 
 fusion of ideas, will be noticed more appropriately under 
 chlorine, with which gas oxygen is often identified in the dye- 
 house. 
 
 Oxygen exists in Nature both free and combined; when free, 
 it forms a colorless and transparent gas, without taste or smell ; 
 it is a little heavier than common air, of which it forms a part, 
 and is dissolved or absorbed by water, in the proportion of 
 from 3 to 4 per cent, by weight. Its wide range of affinity for 
 other elements, its presence in almost every compound, and the 
 part it plays in nature, invest it with an importance not pos- 
 sessed by any of the other elements. It constitutes more than 
 a fifth part of the atmosphere, as much as eight-ninths of the 
 water, and fully half of the solid crust of the globe ; and it is, 
 besides, a prominent ingredient in all animal and vegetable 
 bodies. The following table shows its numerical importance 
 more precisely : — 
 
 Water has .... 8 oxygen in 9 by weight. 
 
 The Air 3 " in 9 " 
 
 Crust of the Earth . . 5 " in 9 " 
 
 Animals and Vegetables 7 " in 9 " 
 
48 
 
 HOW TO MAKE OXYGEN" GAS. 
 
 How to make Oxygen Gas. — The name oxygen was given 
 to this element from the idea which the old chemists had, that 
 it gave acid properties to its compounds. It was first recog- 
 nized in this country as a distinct substance by Dr. Priestley, 
 in the year 1774, and about a year after in Sweden, by Scheele, 
 without any previous knowledge of Priestley's discovery. It 
 was obtained by Priestley by heating, in a retort, red oxide of 
 mercury, which is thereby resolved into fluid mercury and oxy- 
 gen. But other and more economical means are now adopted 
 for its preparation, as follows: An iron bottle is prepared, 
 with an iron tube fitted into the mouth air-tight, forming a 
 retort; into this a quantity of black oxide of manganese is put, 
 and the bottle placed with its contents, into a good fire, with 
 the open end of the iron pipe dipping into a vessel filled with 
 water. The following figure shows the bottle in the fire, with 
 
 planation of what is taking place within the retort-bottle in the 
 fire it may be stated, that the black oxide of manganese is com- 
 posed of Mn0 2 ; the high heat drives off, or sets at liberty, a 
 portion of the oxygen, and the manganese is converted into a 
 lower state of oxidation; so that 3Mn0 2 becomes Mn0 3 ,Mn 
 
 Another and more rapid method of preparing oxygen is, by 
 taking equal parts of oxide of copper and chlorate of potash, 
 and placing the mixture into a small flask or test-tube, fitted 
 
 Fig. 1. 
 
 the conducting pipe. Care must 
 be taken not to allow any of the 
 contents of the bottle to get into 
 the pipe. When the bottle be- 
 comes redhot, bubbles of gas are 
 seen to rise from the pipe through 
 thewater; these bubbles are oxygen 
 gas, and may be collected by filling 
 a bottle or jar with water, and hold- 
 ing its mouth downwards over the 
 extremity of the pipe; the gas as- 
 cending into the bottle or jar, grad- 
 ually displaces the water. In ex- 
 
 0 + 20. 
 
 Fig. 2. 
 
 with a glass tube, as repre- 
 sented by the annexed cut. 
 When heat is applied, by 
 means of a lamp, a rapid 
 evolution of gas takes place, 
 very pure, and without any 
 danger to the operator. One 
 ounce of chlorate of potash, 
 treated in this way, will 
 
HYDROGEN. 
 
 49 
 
 yield about 500 cubic inches of gas. The chlorate of potash is 
 composed of KO CI 0 5 , all the oxygen is set free, and chloride of 
 potassium left. The oxide of copper undergoes no decomposition. 
 The part it plays is not well understood ; but a practical use of 
 its presence in this experiment is, to prevent fusion of the salt, 
 which would take place, and is liable to break the vessel used. 
 When the experiment is finished, and the flask cold, a little 
 water will dissolve out the chloride of potassium from the oxide 
 of copper, which, when dried, may be used again for a similar 
 experiment. There are a variety of other means of obtaining 
 this gas, but they need not be detailed. 
 
 Properties of Oxygen. — Oxygen is an eminent supporter 
 of combustion. If a candle be placed in an atmosphere of this 
 gas, it burns with intense brilliancy. Sulphur and charcoal 
 being kindled, and placed in oxygen, give a vivid light, and 
 there is formed sulphurous acid with the sulphur, and carbonic 
 acid with the charcoal. If a piece of iron or steel wire be made 
 red-hot, and then immersed into oxygen gas, the combination 
 is so rapid, that the heat produced causes the iron to scintil- 
 late, and the oxide to fuse, and drop oft' like water, sufficiently 
 hot to melt or fuse china and glass. Many other metals burn in 
 the same way as iron in this gas. It is upon this gas that depend 
 the processes of combustion and respiration ; and the various 
 functions of organized existence, in all its forms, are essentially 
 connected and sustained through the agency of oxygen. In- 
 deed, there are few operations in chemistry which are not in 
 some way connected with oxygen; so that, under the various 
 heads in which we intend to treat our subject, its nature and 
 properties will be constantly developed. Dyed fabrics, whe- 
 ther wet or dry, suspended in this gas, are not affected, a fact 
 for the dyer to bear in mind when he is identifying this gas 
 with chlorine. 
 
 Hydrogen (H. 1). 
 
 Hydrogen is a gaseous element, never found free or uncom- 
 bined in Nature, but is easily obtained from some of the com- 
 pounds of which it is a component. When pure, it is without 
 smell or color, and is the lightest substance known ; it is there- 
 fore used for inflating balloons. Its distinctive character as 
 an element was first pointed out by Cavendish, in 1766. It 
 exists abundantly in nature, in combination with other ele- 
 ments; it is a constituent of all animal and vegetable substances 
 and, being one of the constitutents of water, it enters as such 
 into the composition of almost all compounds. It is from 
 4 
 
50 
 
 WATER. 
 
 Fi S 3 - the decomposition of water that hydrogen 
 
 is generally prepared for experimental 
 purposes. The process is simple. By 
 putting some iron or zinc into a retort, 
 and pouring over it a little dilute sul- 
 phuric or hydrochloric acid, the metal 
 dissolves with effervescence, and the gas, 
 in passing off, may be caught in bottles or 
 jars over the pneumatic trough, as de- 
 scribed for oxygen. Instead of a retort, a 
 flask or bottle may be used, having a tube 
 fitted by a cork in the mouth of the bottle, 
 
 as represented by the annexed figure. 
 The reaction which takes place, by the acid acting on the 
 metal, is as we have before shown (page 45), 
 
 S0 4 H + Zn = S0 4 Zn + H. 
 
 We observe here that the change is only the substitution of 
 the metal for the hydrogen in the acid. The use of the water 
 mixed with the acid is to dissolve the salt of zinc formed in 
 the process, which requires a considerable quantity of water. 
 From these and similar facts, hydrogen is supposed to be a 
 metal existing in a gaseous form. At all events, its chemical 
 character exhibits many of the properties possessed by the 
 metals. Hydrogen, when prepared in the way described, has 
 a slight smell, which results from impurities in the substances 
 used, generally a small trace of arsenic, or sulphur, in the 
 metal. When iron is used instead of zinc, the smell is still 
 more perceptible. Hydrogen is a combustible gas, and burns 
 with a yellow flame, but does not support combustion. A 
 burning candle immersed in it is instantly extinguished. When 
 mixed with oxygen, and heat is applied, the mixture explodes 
 with a loud report, and water is formed by the union of the 
 gases. Hydrogen does not support life. An animal immersed 
 in an atmosphere of it soon dies. Several attempts have been 
 made to breathe this gas, and some curious effects have been 
 observed ; but from incautiousness in not purifying the gas 
 perfectly before inhaling it, two fatal accidents have followed. 
 All such attempts are extremely foolish. Hydrogen combines 
 with oxygen in two proportions, forming the protoxide or 
 water, and peroxide or binoxide, a substance which has strong 
 bleaching properties. 
 
 Water. — The discovery of the true composition of water 
 was made by Cavendish in 1781, by burning known quantities 
 of oxygen and hydrogen in a dry glass vessel, and observing 
 that water was formed and deposited on the glass, and in quan- 
 
WATER. 
 
 51 
 
 tity exactly equal to the weights of the gases which disappeared. 
 He also found that these gases unite exactly in the proportion of 
 two volumes of hydrogen with one of oxygen, and by weight, 
 1 to 8. 
 
 Pure water is colorless and transparent, and has neither 
 taste nor smell. It is eminently neutral, having neither acid 
 nor alkaline properties, and does not alter the nature of sub- 
 stances put into it. It often enters, however, into the compo- 
 sition of compounds; and many substances put into it have 
 the property of decomposing it, and appropriating its ele- 
 ments. 
 
 The statement that water is entirely neutral, and having no 
 action upon matters put into it, may appear doubtful to the 
 practical dyer, as his daily experience teaches him that the 
 waters he uses have a strong effect upon many of the dyes, 
 and that certain kinds of water are better for some of his colors 
 than others, which manifests a difference either in the condition 
 or constitution of the water. This difference in water, expe- 
 rienced by dyers, depends upon foreign matters dissolved in it. 
 It would, therefore, be a great object for the dyer to obtain 
 pure water; or, if this is not practicable, to know what the 
 ingredients are that are in the water lie is using, so that he may 
 either counteract their effects, and escape their consequences, 
 or render them subservient to his purpose. The great practi- 
 cal importance of water to the dyer is, not only its neutrality, 
 but also its solvent power. The cohesion of solid bodies is 
 thus overcome, and the particles are diffused through those of 
 the water, and so placed in the best possible condition for com- 
 bining with the particles of other bodies brought into proximity 
 with them. We may illustrate this by taking two solid sub- 
 stances that have a strong affinity for each other, say tartaric 
 acid and carbonate of soda; mix them together dry, there will 
 be no apparent action ; but if these substances be previously 
 dissolved in water, and mixed, the action is violent and imme- 
 diate. As may be supposed, therefore, it is its great solvent 
 powers that gives us impure water. 
 
 Water is rendered pure by distillation. When caused to 
 boil, it passes off as steam, and when steam is condensed by 
 cooling, it is pure water, provided the impurities which were 
 in the water before boiling do not fly off at a lower temperature 
 than that of 212°. For instance, gaseous matters are expelled 
 at lower temperatures, and alcohol, which boils at 180°, is also 
 given off; but the impurities that are found in common water 
 to affect the dyer are not given off, except these be in the 
 water in great quantities, as in lyes, in boiling which some of 
 
52 
 
 WATER. 
 
 the soda or potash is carried away with the steam, as already 
 noticed. 
 
 The original source of all our water is from the surface of 
 the ocean ; it is evaporated or vaporized, and carried through 
 the atmosphere in the form of clouds, or in solution, and de- 
 posited upon the earth as dew or rain ; but in this state, it 
 dissolves matters from the atmosphere, such as carbonic acid, 
 ammonia, &c. ; so that rain-water, especially if near towns, 
 is not altogether free of impurities. Nevertheless, when far 
 from towns, or after having fallen for some time to purify the 
 air, rain is the purest water in nature ; but the moment it 
 touches the earth, it dissolves some solid matters, and becomes 
 contaminated with the ingredients of the soil over or through 
 which it passes; and these ingredients cause the differences 
 experienced by dyers. The nature of the impurities depends 
 upon the immediate source of the water, the nature of the soil 
 or strata of earth through which it has passed, and as these 
 substances act and react upon the dyestuffs used, it becomes of 
 the first importance that the dyer should fully comprehend 
 the character and effects of the substances dissolved in the 
 water he is using. These ingredients are generally lime, mag- 
 nesia, alumina, potash, soda, iron, cppper, sulphuric acid, hydro- 
 chloric acid, and carbonic acid. There are also other sub- 
 stances, which have been found in springs, in more minute 
 quantities, but which we need not enumerate here, as they are 
 not common ; and even some of these given, such as copper, 
 are not often present in waters used in the dye house. These 
 earthy substances are generally found in the water combined 
 as sulphates, chlorides, or carbonates. There are also gases 
 present in all waters, as atmospheric air, carbonic acid, sulphu- 
 rous acid, &c. The last named gas is easily detected by the 
 smell, and water could not be used for dyeing containing an 
 appreciable quantity of it. Copper will not be present except 
 in the vicinity of a copper mine, or a copper-ore vein, which 
 would not be a fitting locality for a dye-house. Iron, as a sul- 
 phate, or chloride, is often present in very minute quantity; 
 but when the quantity is considerable, the water is not good 
 for many purposes; and, if the water is conveyed through lead 
 pipes, or retained in leaden tanks, a small trace of lead may be 
 detected, which is not only deleterious to the dyer's operations, 
 but very destructive to health. One common definition of the 
 quality of water is hard and soft; but this expression, so far as 
 regards the dyer, is somewhat ambiguous, and is only useful 
 when alkalies and soaps are to be used. Distilled water is soft 
 and pure, and useful for all purposes of the arts; but a water 
 may be soft and useful for bleaching and washing, and very 
 
WATER. 
 
 53 
 
 deleterious in dyeing; and it may be hard, and yet good for 
 dyeing most colors. Soch a term, therefore, does not denote 
 any particular kinds of impurities. If a piece of pure white 
 soap be dissolved in alcohol, not so strong as to form a jelly, 
 and a little of this solution be dropped into water, if the soap 
 curdles the water is hard; if not, it is soft. If hard, the ingre- 
 dients are of an acid or an earthy nature, such as carbonic acid, 
 carbonate of lime or iron, sulphate of lime, &c. ; if soft it may 
 contain alkalies. The ingredients in the water are often so 
 minute that the ordinary tests do not, for some time, detect 
 them. The best mode of proceeding is to apply the soap test 
 preliminarily, as a sort of guide;* next, to try the water with 
 delicately-prepared test papers, and observe whether it has any 
 acid or alkaline reaction, then take a gallon of the water and 
 boil it down to a pint; put this into a narrow jar, and allow it 
 to settle for a few hours ; pour off the clear liquid into another 
 vessel, and retain the turbid remainder for examination. The 
 insoluble precipitate, if any, will most probably be carbonate 
 and sulphate of lime, and a little iron. Carbonate of lime is 
 held in solution as bi-carbonate ; but the boiling decomposes 
 this compound, one proportion of carbonic acid being given off, 
 and the insoluble carbonate precipitates. The sulphate of lime 
 is soluble only in small quantity, and a little is precipitated by 
 boiling. To the precipitate add a few drops of hydrochloric 
 acid, and the carbonate of lime and iron will dissolve with 
 effervescence, while the sulphate will remain undissolved. A 
 drop or two of gallic acid added to the acid solution will detect 
 iron, by giving a black or bluish color. A portion of this 
 solution may be taken, and a little ammonia added to neutralize 
 the acid; if lime is present, the addition of a little oxalate of 
 ammonia will give a white precipitate. 
 
 The pint of water boiled down is now divided into five 
 different portions, and put into small wine or test glasses. 
 
 To one portion are added a few drops of gallic acid, which, if 
 iron be present, will, after standing some time, produce a bluish 
 color. 
 
 To another portion add a few drops of oxalate of ammonia, 
 which will give a white precipitate if lime is present. This 
 should be heated a little. 
 
 To a third portion add a few drops of phosphate of soda, 
 and stir it well. After standing some time, if a white precipi- 
 tate be formed, this will indicate the presence of magnesia. 
 
 * The soap test for water lias been carried out to a great extent, and pro- 
 bably to general practical use, by Professor T. Clark. (See his papers in the 
 Chemical Gazette,) 
 
54 
 
 WATER. 
 
 To a fourth portion add chloride of barium; if a white pre- 
 cipitate is obtained, which is not redissolved by adding a little 
 pure nitric acid, sulphuric acid is present. 
 
 To the fifth portion add nitrate of silver; if a white precipi- 
 tate is formed, not redissolved by the addition of a little pure 
 nitric acid, then hydrochloric acid is present. 
 
 These tests, and the nitric acid used, of course, must be per- 
 fectly pure, or no dependence can be placed upon the results. 
 
 If carbonic acid exists in the water, which it does very com- 
 monly in combination with a base, it will be known, as already 
 intimated, by the effervescence caused by the addition of an 
 acid ; but it may exist free ; and the best way to detect it, is to 
 take a separate quantity of the water, without boiling, say a 
 pint, and add to it a little clear lime-water ; if milkiness appear, 
 carbonic acid is present, either free or as bi-carbonate of lime. 
 
 If blue litmus paper be reddened, there is free acid present 
 in the water. 
 
 This manner of proceeding, which is very simple, is sufficient 
 to give the dyer an idea of the impurities he has to contend 
 with. Of course, the effects of each of these separately, or 
 together, upon his dye-drugs, will also have to be studied; but 
 this we refer to the separate heads under which they naturally 
 fall. Should a more correct investigation be required, such as 
 the exact quantities of each ingredient, this must be done by a 
 regular course of analysis, which, we are afraid, few practical 
 dyers have the apparatus, or other means of making. How- 
 ever, with the tests referred to, a near approximation may be 
 come at, by boiling the gallon of water to dryness, and care- 
 fully weighing the contents, which will give the whole solid 
 matters in the gallon; and afterwards, by dissolving this in dis- 
 tilled water, pouring off the solution, and drying the insoluble 
 portion, the quantity of soluble salts, which may be those of 
 potash, soda, magnesia, &c, will be found. The water is tested 
 for these and all the other ingredients, by the tests given. To the 
 remaining insoluble part, a few drops of hydrochloric acid are 
 added; and notice is taken if this produces effervescence. This 
 acid solution is then diluted with distilled water, and tested as 
 above; if anything remains insoluble, it is again dried and 
 weighed, and the result will indicate the silica present. The 
 following table, from Parke's Chemical Essays, a book well 
 worth perusal by practical men s will be a guide to the testing 
 of water: — 
 
WATER. 
 
 55 
 
 TEST USED. 
 
 Oxalates, or oxalic acid. 
 Litmus. 
 
 Turmeric paper. 
 Chloride of platinum in 
 
 cohol. 
 Nitrate of silver. 
 Salts of barytes. 
 Lime-water. 
 
 Acetate of lead. 
 
 Chloride of lime. 
 Polished iron. 
 Phosphate of soda. 
 
 For the particular effects of some of these tests, the reader is 
 referred to the articles upon these substances. 
 
 Water is used in the dye-house principally as a solvent ; but 
 its solvent property depends upon certain laws. The action 
 being the mutual attraction between the solid and fluid; it 
 becomes weaker as the attractions are satisfied. If, for example, 
 we take a piece of white sugar of lead, t and immerse one small 
 point of it in water, the liquid is quickly drawn up into its 
 pores, and adheres to the particles of the salt. If more water 
 than is merely sufficient to wet the particles is allowed to enter, 
 the solid particles of the salt break down and disappear in the 
 water ; in other words, the salt is dissolved. But this action of 
 the water upon the salt is limited; it is very powerful at first, 
 but the salt becoming diffused through the liquid, the action 
 upon the solid decreases gradually, until the water gets satisfied, 
 and will dissolve no more; the water is then said to be satu- 
 rated. 
 
 An important point in dissolving salts may here be noticed. 
 In dissolving quantities of crystallized salts, such as alum, 
 sugar of lead, &c, the custom is to put the solid crystals into 
 a vessel, and pour water upon them ; and a person keeps stir- 
 ring until the whole is dissolved. This takes up much valua- 
 ble time, and there is often a remainder of the salt not dissolved. 
 If, instead of proceeding in this way, the quantity of water 
 which it is necessary to use be put into the vessel, and the 
 crystals of the salt be suspended upon the surface, the solution 
 would proceed much more rapidly, and more economically, 
 than any other way. As the particles of water take up the 
 particles of the salt, they become heavier, and sink ; other par- 
 ticles take their place, dissolve more of the salt, and sink in 
 turn ; so that the action of a constant current of liquid is kept 
 
 WILL DETECT. 
 
 Lime, or its salts. 
 Uncombined acids. 
 Alkalies and alkaline earths. 
 
 | Salts of potash. 
 
 Hydrochloric acid or chlorides. 
 
 Sulphuric acid or sulphates. 
 
 Carbonic acid, 
 f Sulphuretted hydrogen in be- 
 \ coming black, or sulphates. 
 
 Carbonated alkalies. 
 
 Copper (is precipitated). 
 
 Magnesia. 
 
56 
 
 WATER. 
 
 up on the suspended crystals, and always of that portion of the 
 liquid most capable of dissolving. When crystals of any salt 
 are put into a vessel, and water poured over them and allowed 
 to remain, they are a very long time in being dissolved ; as 
 the water surrounding the crystals becomes saturated, and 
 incapable of dissolving more, and from its weight it remains at 
 the bottom of the vessel. This may be beautifully illustrated 
 by taking three tumblers filled with water, and adding to each 
 an equal weight of crystallized sulphate of copper. In the one, 
 let the crystals rest at the bottom, stir the other constantly, and 
 let the third be suspended upon the surface of the water ; the 
 action will be seen, and the difference in time appreciated. 
 
 In general, hot water dissolves more of a salt than cold wa- 
 ter ; but the relation of different dissolving powers of water, at 
 different temperatures, and for different salts, is very curious. 
 Some salts dissolve equally at all temperatures, such as com- 
 mon salt. Some salts dissolve least in cold water, and increase 
 gradually as the water is heated ; others again, increase rapidly, 
 until the water is at a certain temperature, and then become 
 less soluble ; while other substances, such as lime, dissolve 
 most easily when the water is cold. Thus, 66 gallons water, 
 at 32° Fah. dissolve 1 lb. lime ; but it will take 75 gallons at 
 60° Fahr., or 128 gallons at 212°, to produce the same effect ; 
 so that boiling water can contain only about half of the lime 
 that ice-cold water can. Thus, when lime-water, at 60°, which 
 is about the maximum heat of water in summer, is boiled, a 
 quantity of lime is deposited as the heat increases. This is 
 often experienced in the raising of chrome oranges. 
 
 The following table illustrates these remarks, and is of the 
 greatest value to the dyer : — 
 
 2° 50° 6S° 86° 104° 122° 140° 158° 176° 194° 212° 230° 
 
WATER. 5T 
 
 v. ■ 
 
 It will be seen here that if a salt is dissolved in boiling wa- 
 ter to saturation, and allowed to cool, a great quantity will be 
 deposited either as crystals or powder; also, if we wish to have 
 a highly-saturated solution, there are certain temperatures bet- 
 ter adapted for obtaining it than others. The best means is to 
 use the salt dissolved in cold water, as above stated ; and the 
 dyer, while he uses his stuff, as the salts of iron ; alum, &c, 
 should know that when he uses the full of a ladle, or pail, or 
 small mug, he is taking exactly so many ounces or pounds of 
 the salt, not so many measures, as is generally the case, without 
 reference to the particular strength of the solution. 
 
 The following table of the quantity of a salt dissolved in 
 a gallon of cold water (60° Fah.), at saturation will be an ex- 
 ample of this : — 
 
 Common salt 3.6 lb. per gallon. 
 
 Sal-ammoniac 3.3 — 
 
 Sulphate of copper 3.8 — 
 
 Sulphate of iron 6.66 — 
 
 Sulphate of zinc (anhydrous) . . 5.0 — 
 
 Sulphate of nickel 3.3 — 
 
 Sulphate of soda (hydrated) . . 3.7 — 
 
 Alum 1.2 — 
 
 Comparing this with the diagram above, it will be seen that 
 double the quantity of some of these salts is dissovled in boiling 
 water. 
 
 Besides the property for dissolving solid bodies, which we 
 have been considering, water, as has been previously said, has 
 also the property of dissolving gases, and holding them in 
 solution. In this case, cold water is a more powerful solvent 
 than hot. Some gases, if held in solution by water used in 
 dyeing, would be very deleterious; and as many of these gases 
 are often floating about in the dye-house, they may be absorbed 
 by the water in small quantities, and be injurious, and the 
 cause of the injury may not be known or thought of. The 
 following are a few of these gases, and their solubility in 
 water. 
 
 100 volumes, or cubic inches of water, at 60°, will dissolve 
 about — 
 
 253 volumes of sulphuretted hydrogen, weighing 93.6 grains. 
 4380 " sulphurous acid, " 3000.0 " 
 
 206 " chlorine, " 155.7 " 
 
 100 " carbonic acid, " 47.2 " 
 
 76 " nitrous oxide, " 75. " 
 
 Any of these gases, in the water, will affect colors, and they 
 are all, to some extent, gases given off in the dye-house. 
 
58 
 
 NITROGEN". 
 
 One gallon is equal to 277 cubic inches, so that each gallon 
 is capable of holding in solution. — 
 
 259.3 grains of sulphuretted hydrogen. 
 8310. grains of sulphurous acid. 
 431.3 grains of chlorine. 
 130.7 grains of carbonic acid. 
 207.7 grains of nitrous fumes. 
 
 Bin-oxide of Hydrogen. — Bin-oxide of hydrogen is a color- 
 less liquid like water ; it has a metallic taste, and bleaches 
 almost instantly all organic colored substances. Its preparation 
 is difficult and expensive. It is obtained by the decomposition 
 of bin-oxide of barium; the preparation of which is also difficult. 
 There are so many minute precautions required for the prepara- 
 tion of the bin-oxide of hydrogen, that almost no description 
 which our limits permit would enable the student to prepare 
 it ; these are all given in detail, by Thenard, the discoverer of 
 the compound, in his Traite de Qhimie (vol. i., 6th edition). 
 
 Could there be any means of procuring it readily and cheap, 
 its uses would be invaluable, both as a bleaching agent and also 
 for oxidizing, and many other operations in the arts. It is 
 often referred to in proof that oxygen has bleaching properties 
 as well as chlorine, a fact which will be noticed to some extent 
 under that element. 
 
 Hydrogen combines with other elements besides oxygen, 
 giving rise to important compounds, such as sulphuretted hy- 
 drogen, a gas we have just referred to, and others which will be 
 treated of under the separate elements with which it combines. 
 
 Nitrogen (N. 14). 
 
 If a small vessel be floated upon water, with a piece of phos- 
 phorus in it, and this be set on fire, and a glass jar be inverted 
 
 over it, as represented by the annexed 
 Fig 4. figure, the flame is soon extinguished, 
 
 and the water, when the air within 
 the glass cools, rises into the jar. Let 
 the whole stand until the white fumes 
 in the glass disappear, the remaining 
 air in the jar will be found to differ 
 entirely from common air; a candle 
 will not burn in it, and an animal put 
 into it would very soon die. This 
 gaseous substance is nitrogen. The 
 atmosphere* is composed of oxygen 
 and nitrogen ; and the burning phosphorus combines with the 
 former of these gases, forming phosphorous acid, constituting 
 
NITROGEN". 
 
 59 
 
 the white cloud referred to, which is absorbed by the water 
 after a little time. The rising up of the water into the jar is to 
 supply the place occupied by the oxygen consumed, and nothing 
 but nitrogen remains. 
 
 This element was first called Azote — the life-destroyer — 
 by its discoverer, Dr. Rutherford, from its not having the 
 power of supporting life ; but the name was afterwards changed 
 to nitrogen, on account of its being found to be the basic con- 
 stituent of nitric acid (aqua-fortis). Nitrogen has neither taste 
 nor smell, and is rather lighter than oxygen. Its use in the 
 atmosphere is supposed to be for diluting the oxygen ; but there 
 is ,no doubt that other important purposes are served by its 
 presence in the air, although we may be ignorant of them, as 
 it forms an essential constituent of animals and vegetables, and 
 also of many mineral productions. Nitrogen is peculiar for 
 what are termed inert or negative properties. We cannot cause 
 it to combine directly with any other element, as we do oxygen 
 and hydrogen, or hydrogen and chlorine; nevertheless, it com- 
 bines with a number of elements, when their compounds are 
 being decomposed. 
 
 With oxygen, nitrogen forms a variety of interesting com- 
 pounds, already alluded to (page 38), but which we will here 
 notice more in detail, particularly those more commonly met 
 with. As already remarked, the atmosphere is a mixture of 
 nitrogen and oxygen, found to be in very nearly the same pro- 
 portions under all circumstances and at all places, not in chemi- 
 cal union, but maintained in equal mixture by the principle of 
 diffusion. There are a variety of methods for ascertaining the 
 proportions of oxygen and nitrogen in the air; the one just 
 described, the burning of phosphorus in an inverted jar over 
 water, will suffice as an example. The results of careful inves- 
 tigations into this subject give as the constitution of the atmos- 
 phere in 100 parts : — 
 
 21 Oxygen. 
 79 Nitrogen. 
 
 But, from the constant evaporation of water from the sea and 
 surface of the earth, and the production, by many causes, of 
 carbonic acid gas, which finds its way into the atmosphere, the 
 air always contains a small portion of those ingredients, which 
 being taken into account, makes the composition : — 
 
 Oxygen ' 20. 
 
 Nitrogen 79. 
 
 Vapor of water ..... 0.9. 
 Carbonic acid 0.1. 
 
 100.0 
 
60 
 
 BINOXIDE OF NITROGEN". 
 
 The dyer cannot fail to have observed a thin crust of solid 
 matter upon the surface of his lime solution, bleaching liquor, 
 and blue vats. This crust is the carbonate of lime, and is 
 caused by the carbonic acid in the air combining with the lime, 
 and forming an insoluble carbonate. The presence of this gas 
 in the air has no deleterious effects in the dye-house, so far as 
 we know, except its combining with caustic alkalies, if exposed, 
 and deteriorating them. 
 
 The oxygen of the atmosphere plays a very prominent part 
 in the dye-house, and the knowledge of the true constitution of 
 the air will make many of these phenomena better understood. 
 This gas not being in chemical union with the nitrogen, there 
 is no chemical force retaining and preventing it from acting 
 upon other bodies, when brought under its influence. 
 
 The principal compounds formed between nitrogen and 
 oxygen are : — 
 
 Protoxide of nitrogen .... NO. 
 
 Deutoxide of nitrogen .... N0 2 . 
 
 Nitrous acid ...... N0 3 . 
 
 Peroxide of nitrogen .... N0 4 . 
 
 Nitric acid ...... N0 5 . 
 
 Some of these being of no known importance in the dye- 
 house, we need do little more than refer to the condition in 
 which they may be found. 
 
 Protoxide of Nitrogen* is a gaseous body, and is easily 
 obtained by distilling nitrate of ammonia in a retort as described 
 for obtaining oxygen (page 48), and collecing the gas as it 
 escapes over water. It is known under the appellation of 
 laughing gas. 
 
 Binoxide of Nitrogen is also a gaseous body, and is evolved 
 when metals are being dissolved in nitric acid. When dissolv- 
 ing iron or copper in nitric acid, in open vessels, as is done for 
 the preparation of mordants, a dense red gas is seen to escape 
 during the process. This red gas is produced by the binoxide 
 of nitrogen combining with the oxygen in the atmosphere, 
 and forming a peroxide; but when the metal is dissolved in a 
 retort, or other close vessel, as described for hydrogen, and the 
 gas collected in*a glass jar, it is found perfectly colorless. The 
 following* is the reaction which takes place when a metal is 
 being dissolved in nitric acid and oxide of nitrogen envolved. 
 Every three proportions of metal require four proportions of 
 acid, one of which is decomposed according to the following 
 formula, supposing copper to be the metal dissolved : — 
 3Cu + 4N0 5 = 3Cu 0 N0 5 + N0 2 . 
 
NITRIC ACID. 
 
 61 
 
 But, according to the theory of salt radicals (page 45), the reac- 
 tion is the following: — 
 
 3Cu + 4N0 6 H = 3Cu N0 6 + 4HO, N0 2 . 
 
 According to either view of the reactions which take place, 
 it will be observed that the proportions are the same, which 
 may enable the dyer to guide himself in these substances when 
 making nitrates of iron or copper. 
 
 Nitrous Acid. — This acid is prepared by taking four 
 volumes of the binoxide of nitrogen, adding to them one 
 volume of oxygen, and exposing this mixture to a low degree 
 of Qold ; the gases, under these circumstances, unite, and form a 
 greenish-colored liquid, which is nitrous acid. As may be 
 supposed, from the manner in which it is prepared, this sub- 
 stance is very volatile. If thrown into water it is decomposed. 
 But it can be obtained by several means, in combination with 
 bases, such as potash, soda, lead, &c, with which it is more 
 stable. 
 
 Peroxide of Nitrogen. — This compound is formed when 
 the binoxide of nitrogen is allowed to escape into the atmo- 
 sphere, and constitutes the red fumes observed when dissolving 
 iron or copper in nitric acid. It is also obtained by distilling 
 nitrate of lead in a retort, and allowing the fumes to pass into 
 a bottle or flask kept cool by placing it in a freezing mixture, 
 such as snow and salt. It condenses in this vessel* and forms 
 a reddish-yellow liquid, which, however, passes off' as gaseous 
 fumes, by the slightest elevation of temperature. These fumes 
 are very corrosive: they are fatal to animal and vegetable life, 
 and rapidly destroy all colors, and also the fibres of the cloth 
 or yarn exposed to their action. The dissolving of metals in 
 nitric acid should, therefore, never be carried on within or near 
 the dye-house, or any place where goods are exposed. We 
 have seen a little inattention to these precautions destroy the 
 labor of several days, and this, too, w r hen the destructive agent 
 was hardly perceptible to the senses, although its odor is 
 amongst the most easily detected of gaseous compounds. This 
 gas is also very suffocating and hurtful to health, and care 
 should be taken that it is not breathed. It is its presence in 
 nitric acid which gives that acid the reddish-brown color which 
 the aqua-fortis of commerce often has. 
 
 Nitric Acid. — This acid exists abundantly in nature, in com- 
 bination with other substances forming nitrates. We have 
 said before that nitrogen and oxygen do not combine directly 
 in the same manner as oxygen and hydrogen. There is no 
 doubt, however, that the nitric acid which is found united with 
 bases in nature, has been the result of the union of the oxygen 
 
62 
 
 NITRIC ACID. 
 
 and nitrogen of tbe atmosphere. When a quantity of hydrogen 
 is mixed with nitrogen in an open vessel, and ignited, it burns 
 rapidly in contact with the oxygen of the air, forming water ; 
 and the water thus formed is found to contain nitric acid. If 
 electric sparks be passed through air, confined in a vessel above 
 a solution of an alkali, a portion of the alkali is converted into 
 a nitrate. Eain which falls during a thunderstorm, almost 
 always contains nitrate of ammonia. Ammonia is always being 
 given into the air by the decomposition of animal and vegetable 
 substances, and absorbed by the watery vapor ; so that when 
 electric currents pass through the air during a thunderstorm, 
 the nitric acid formed combines with this ammonia, forming 
 a nitrate. In warm climates, where electric currents are 
 abundant, the quantity of ammonia in the air is considerable ; 
 the formation of nitrate of ammonia is, therefore, proportionably 
 great; and this, being washed down by the rain into porous 
 limestone soils, is decomposed by the nitric acid combining 
 with the lime and also with potash and soda, which are general 
 constituents of soils, forming nitrates with these bases, and the 
 ammonia is accordingly liberated, either to be given to the air 
 again, or taken up by plants, as a constituent of their food. In 
 this way, immense beds of nitrates have been formed in the 
 East Indies and in South America. In Chili and Peru, there 
 are found large deposits of nitrate of soda upon the surface of 
 the soil. Great quantities of nitrate of potash and soda are 
 imported from these localities for the various manufacturing 
 purposes of this country, where they are now extensively 
 applied. The nitrate of lime and other earths, are converted 
 into nitrate of potash, by mixing them with carbonate of potash, 
 before sending them to this country. 
 
 Nitric acid is prepared from the nitrate of potash or soda, 
 by decomposing it with sulphuric acid. This may be done, on 
 a small scale, by putting a little of any of these salts into a 
 retort, adding some sulphuric acid, and then applying heat. 
 The beak of the retort is inserted into a receiver, which must 
 be kept cool by causing cold water to drop upon it. The 
 arrangement of the apparatus is indicated by the annexed 
 figure. 
 
 At the beginning of this experiment, red fumes of peroxide 
 of nitrogen come off; but soon after a colorless liquid is seen to 
 distil over, and drop into the receiver — this is nitric acid. The 
 reaction which takes place may be represented by the following 
 formula : — 
 
 Na N0 6 + S0 4 H - Na S0 4 + N0 6 H. 
 
 Nitrate of soda is now more generally used than potash, 
 being cheaper, and having a lower combining equivalent, more 
 
NITRIC ACID. 
 
 63 
 
 nitric acid is obtained from a given weight. Thus, 100 lbs. of 
 nitrate of potash give 62 lbs. of acid; while 100 lbs. of nitrate 
 
 Fig. 5. 
 
 of soda would give 74 lbs. The best proportion of sulphuric 
 acid to use with nitrate of potash is 2 equivalents, whereas less 
 suffices with nitrate of soda. 
 
 Nitric acid is generally prepared, on the large scale, in iron 
 cylinders, placed so that a fire plays round them. Into these 
 cylinders are put the materials; and the acid vapors which are 
 distilled over are conveyed to the condensing apparatus by 
 glazed earthenware pipes. 
 
 The nitric acid of commerce has generally a light-brown co- 
 lor, caused, as before stated (p. 61), by having a little peroxide 
 of nitrogen in it. Sir H. Davy drew out the following table of 
 proportions of nitrous gas contained in this acid, from its 
 shades of color. Thus, in. 100 parts — 
 
 Peroxide of 
 
 Color. 
 
 A pale yellow has . 
 A' bright yellow has 
 A dark orange has 
 A light olive has 
 A dark olive has 
 A bright green has 
 A blue green tras 
 
 This table must be considered to refer only to strong acid, 
 for the color is changed by dilution. Thus, when water is 
 added to the dark orange-colored acid, it changes it to a green- 
 ish-yellow. 
 
 Exposure to the sun's light produces change of color, by de- 
 composing the acid, and liberating peroxide of nitrogen, which 
 remains dissolved in the acid. A little oxygen gas is, at the 
 same time, evolved ; and, if the bottle is stoppered, will either 
 drive it out or burst the bottle, a fact too often experienced. 
 
 Real Acid. 
 
 Water. 
 
 Nitrogen 
 
 . 90.5 
 
 8.3 
 
 1.2 
 
 . 88.9 
 
 8.1 
 
 .2.9 
 
 . 86.8 
 
 7.6 
 
 5.5 
 
 . 86. 
 
 7.5 
 
 6.4 
 
 . 85 4 
 
 7.5 
 
 7.4 
 
 . 84.8 
 
 7.4 
 
 7.7 
 
 . 84.6 
 
 7.4 
 
 8. 
 
61 
 
 NITRIC ACID. 
 
 The great effect of light upon this acid may be tried by placing 
 a little of the colorless acid in the rays of the sun, and observing 
 the change that follows ; this will show the propriety of keep- 
 ing nitric acid always in the dark. Neither should it be 
 exposed to the a ir, by leaving the stoppers out of the bottles or 
 carboys, as it thereby loses it strength rapidly. 
 
 The nitric acid, formed as we described, is often contaminated 
 with iron, from the retorts, and also with sulphuric and hydro- 
 chloric acids, from a little common salt and other impurities 
 being in the nitre used. It is purified from these matters by 
 redistilling in glass retorts. The acid coming off' first in the 
 distillation contains some hydrochloric acid ; then nothing but 
 pure nitric acid passes over, until nearly three-fourths of this 
 acid is distilled. But if the operation be pushed farther, there 
 is danger of impurities passing over. Of course, what remains 
 in the retort contains the impurities. 
 
 Sometimes the quantity of impurities in the nitric acid of 
 commerce is very considerable, and very deleterious to the 
 dyer. The general test applied to this acid in the dye-house 
 is the specific gravity, taken by Twaddell's hydrometer ; but 
 density is often given to the acid by dissolving a little nitre in 
 it, or adding sulphuric acid. We have seen nitric acid, with 
 8 per cent, of sulphuric acid, giving it a high specific gravity. 
 We have also seen it with as much as five percent, hydrochloric 
 acid. The presence of either of these acids is disadvantageous 
 for the preparation of many of the mordants, as will be noticed 
 under the proper heads. 
 
 When nitric acid contains ?ittre, or any other salt dissolved 
 in it, the impurity may easily be detected by evaporating to 
 dryness a little of the acid, either upon a piece of glass or a 
 porcelain plate ; when the acid is pure no residue is left. 
 
 The presence of sulphuric acid is detected by diluting a small 
 portion of the acid with four or five times its volume of 
 distilled water, and adding a little solution of nitrate of 
 barytes, which will give a white precipitate if sulphuric acid is 
 present. 
 
 Hydrochloric acid, or chlorine, may be detected by adding a 
 little nitrate of silver to the dilute acid, which will also give a 
 white precipitate if any hydrochloric acid be present. 
 
 Iron is detected by adding a little gall water to the dilute 
 acid, a bluish-black color then appears. Or, if on evaporating 
 a small portion of the acicl, there is a residue of a brown color, 
 it indicates the presence of iron. 
 
 After having tested for the presence of these substances, and 
 finding the acid pure, or nearly so, then the specific gravity 
 may be taken, as a farther certainty of the value of the acid. 
 
NITRIC ACID. 
 
 65 
 
 This varies much with the acids of commerce, but is generally 
 about 1.300=60° Twaddell, although it may be made as high 
 as 1.500=100° Twaddell. Nearly all the hydrometers used 
 in this country are those known as Twaddell's, which is an ar- 
 bitrary scale. The true specific gravity may be reduced to 
 Twaddell's, by dividing the fractional figures by 5, as will be 
 observed from the above. But in trying the acids by a 
 Twaddell's hydrometer, the above rule is to be reversed ; we 
 then multiply the degree of Twaddell by 5, add 1000, and 
 divide the sum by 1000. Thus supposing the specific gravity 
 to be 60° of Twaddell, then 60 X 5=300 ; which, increased bv 
 100Q, becomes 1300; and this, divided by 1000, gives 1.300, 
 the true specific gravity. Or say 64° Twad., which is a com- 
 
 , (64 x 5) + 1000 1320 1 Qon . fl 
 
 mon number, then ^ J - = = 1.320 specific 
 
 1000 1000 F 
 
 gravity. The following table shows the quantity of acid in 100 
 
 parts, which may be called ounces or pounds or any weight 
 
 convenient, according to the true specific gravity : — 
 
 TABLE OF THE QUANTITY OF ACIDS IN 100 PARTS BY WEIGHT. 
 
 Specific gravity. 
 
 Acid in 100 parts. 
 
 Specific gravity. 
 
 Acid in 
 
 1.5000 . 
 
 . . 100 
 
 1.4189 . 
 
 . . 75 
 
 1.4980 . 
 
 . . 99 ■ 
 
 1.4147 . 
 
 . . 74 
 
 1.4960 . 
 
 . . 98 
 
 1.4107 . 
 
 . . 73 
 
 1.4940 . 
 
 . . 97 
 
 1.4065 . 
 
 . . 72 
 
 1.4910 . 
 
 . . 96 
 
 1.4023 . 
 
 . . 71 
 
 1.4880 . 
 
 . . 95 
 
 1.3978 . 
 
 . . 70 
 
 1.4850 . 
 
 . . 94 
 
 1.3945 . 
 
 . . 69 
 
 1.4820 . 
 
 . . 93 
 
 1.3882 . 
 
 . . 68 
 
 1.4790 . 
 
 . . 92 
 
 1.3833 . 
 
 . . 67 
 
 1.4760 . 
 
 . . 91 
 
 1.3783 . 
 
 . . 66 
 
 1.4730 . 
 
 . . 90 
 
 1.3732 . 
 
 . 65 
 
 1.4700 . 
 
 . . 89 
 
 1.3681 . 
 
 . 64 
 
 1.4670 . 
 
 . . 88 
 
 1.3630 . . 
 
 . 63 
 
 1.4640 . 
 
 . . 87 
 
 1.3579 . . 
 
 . 62 
 
 1.4600 . 
 
 . . 86 
 
 1.3529 . . 
 
 . 61 
 
 1.4570 . 
 
 . . 85 
 
 1.3477 . . 
 
 . 60 
 
 1.4530 . 
 
 . . 84 
 
 1.3427 . . 
 
 . 59 
 
 1.4500 . 
 
 . . 83 
 
 1.3376 . . 
 
 . 58 
 
 1.4460 . 
 
 . . 82 
 
 1.3323 . . 
 
 . 57 
 
 1.4424 . 
 
 . . 81 
 
 1.3270 . . 
 
 . 56 
 
 1.4385 . 
 
 . . 80 
 
 1.3216 . . 
 
 . 55 
 
 1.4346 . 
 
 . . 79 
 
 1.3163 . . 
 
 . 54 
 
 1.4306 . 
 
 . . 78 
 
 1.3110 . . 
 
 . 53 
 
 1.4269 . 
 
 . . 77 
 
 1.3056 . . 
 
 . - 52 
 
 1.4228 . 
 
 . . 76 
 
 1.3001 . . 
 
 . 51 
 
66 
 
 NITRIC ACID. 
 
 Specific gravity. 
 
 Acid in 100 parts. 
 
 Specific gravity. 
 
 Acid in 100 parts. 
 
 1.2947 . 
 
 . . 50 
 
 1.1403 . 
 
 . . 25 
 
 1.2887 . 
 
 . . 49 
 
 1.1345 . 
 
 . . 24 
 
 1.2826 . 
 
 . . 48 
 
 1.1286 . 
 
 . . 23 
 
 1.2765 . 
 
 . . 47 
 
 1.1227 . 
 
 . . 22 
 
 1.2705 . 
 
 . . 46 
 
 1.1168 . 
 
 . . 21 
 
 1.2644 . 
 
 . . 45 
 
 1.1109 . 
 
 . . 20 
 
 1.2583 . 
 
 . . 44 
 
 1.1051 . 
 
 . . 19 
 
 1.2523 . 
 
 . . 43 
 
 1.0993 . 
 
 . . 18 
 
 1.2462 . 
 
 . . 42 
 
 1.0935 . 
 
 . . 17 
 
 1.2402 . 
 
 . . 41 
 
 1.0878 . 
 
 . . 16 
 
 1.2341 . 
 
 . . 40 
 
 1.0821 . 
 
 . . 15 
 
 1.2277 . 
 
 . . 39 
 
 1.0764 . 
 
 . . 14 
 
 1.2212 . 
 
 . . 38 
 
 1.0708 . 
 
 . . 13 
 
 1.2148 . 
 
 . . 37 
 
 1.0651 . 
 
 . . 12 
 
 1.2084 . 
 
 . . 36 
 
 1.0595 . 
 
 . . 11 
 
 1.2019 . 
 
 . . 35 
 
 1.0540 . 
 
 . . 10 
 
 1.1958 . 
 
 . . 34 
 
 1.0485 . 
 
 . . 9 
 
 1.1895 . 
 
 . . 33 
 
 1.0430 . 
 
 . . 8 
 
 1.1833 . 
 
 . . 32 
 
 1.0375 . 
 
 . . 7 
 
 1.1770 . 
 
 . . 31 
 
 1.0322 . 
 
 . . 6 
 
 1.1709 . 
 
 . . 30 
 
 1.0267 . 
 
 . . 5 
 
 1.1648 . 
 
 . . 29 
 
 1.0212 . 
 
 . . 4 
 
 1.1587 . 
 
 . . 28 
 
 1.0159 . 
 
 . . 3 
 
 1.1526 . 
 
 . . 27 
 
 1.0106 . 
 
 . . 2 
 
 1.1465 . 
 
 . . 26 
 
 1.0053 . 
 
 .. . 1 
 
 The presence of free nitric acid in a solution is easily ascer- 
 tained by the production of red fumes when a metal is put 
 into it, such as iron or copper ; or by adding to the substance 
 supposed to contain it a drop of sulphate of indigo, and heat- 
 ing the solution to the temperature of boiling; the indigo will 
 be discolored if nitric acid is present. But if the acid is com- 
 bined with a base, such as soda or potash, this test will not 
 answer. In that case the best mode of proceeding is to put 
 a little sulphuric acid into the liquid suspected, and then to 
 add a crystal of sulphate of iron (copperas). If nitric acid 
 be present, a ring of an olive-brown colored liquid will form 
 around the crystal as it dissolves ; and by applying heat, the 
 well-known smell of nitrous fumes is felt. By these simple 
 means, the dyer can easily ascertain if nitric acid is present, 
 either free or combined, in any compound with which he is 
 working. The action of nitric acid on the different metals will 
 be noticed under the proper heads ; but one remarkable cir- 
 cumstance connected with this class of action must have been 
 observed by most dyers when dissolving iron, namely, that on 
 
AMMONIA. 
 
 67 
 
 putting the iron into the acid, it often remains without any ac- 
 tion ; when this occurs with new acid, complaints are made that 
 the acid is bad or weak, or that something is wrong that pre- 
 vents it dissolving the iron ; and not unfrequently have we 
 seen carboys of acid returned on this account. Recently, we 
 had a sample of such acid, and found it to stand in specific grav- 
 ity 1.425 ; and to contain a mere trace of salts and sulphuric 
 acid, with 0.1 per cent, of hydrochloric acid. It was a strong 
 and comparatively pure nitric acid, which was its fault. The 
 cause of the iron not being acted upon, is from a condition 
 which iron is known to assume, termed the passive state; in 
 which condition acids do not act upon it. Strong and pure 
 nitric acid places the iron in this state, and therefore it is not 
 dissolved till the acid is diluted, or heat applied. We cite the 
 above case as an illustration of the value a little attention to 
 chemical principles would be in many dye-houses, not only in 
 saving money, but also preventing the manufacturer being 
 necessitated either to adulterate or dilute his acid, in order to 
 preserve a good and profitable customer. 
 
 Nitric acid is very corrosive, from which property it was 
 named aquafortis. It destroys all organic bodies, both vege- 
 table and animal. It converts vegetable matter into oxalic, 
 carbonic, and several other acids. Animal substances are 
 acted upon by this acid, producing the yellow-colored com- 
 pounds, observed when it comes in contact with the skin or 
 nails. It should be used at all times with great care. 
 
 Ammonia. — Nitrogen combines with hydrogen, and forms 
 a very important compound, ammonia; composed of one pro- 
 portion of nitrogen and three hydrogen, NH 3 . Ammonia is 
 abundantly obtained from the destructive distillation of organic 
 matters containing nitrogen, such as bones, horns, skins, blood, 
 and other animal matters. It is also obtained as a product in 
 the gas-works. When animal matters are decomposed by 
 burning or putrefaction, ammonia is formed, and produces the 
 disagreeable smell which these operations generally give. 
 
 The ammoniacal liquors obtained from gas-works, or by dis- 
 tilling animal matters, are saturated with hydrochloric acid 
 which converts the ammonia into hydrochlorate of ammonia, 
 (sal-ammoniac), which crystallizes in a very impure state. These 
 crystals are collected and put into iron pots, set in a furnace 
 lined with fire-tiles, and having a large cover or head of lead 
 fitted to them. Fire is applied to the pots, the sal-ammoniac 
 sublimes and collects as a crust upon the leaden top, from 
 which it is removed from time to time. 
 
 Ammonia is prepared by mixing equal parts of slaked lime 
 and sal-ammoniac, and applying heat. The lime combines with 
 
68 
 
 CHLORINE. 
 
 the hydrochloric acid, and the ammonia passes off' as a gas, and 
 is conducted by a pipe into water, with which it combines, and 
 forms liquid ammonia. 
 
 Ammonia, long known as hartshorn, is a strong alkali, and 
 has a very pungent, sharp smell. It is an exceedingly valuable 
 reagent in the laboratory, both as a test and for making many 
 interesting salts by combination with acids, the greater number 
 of which are volatile. These salts are, however, not much used 
 in the dye-house. Ammonia is sometimes used for the prepa- 
 ration of archil, for bringing out the color. Its action upon the 
 coloring matter of the woods is very powerful. It is the 
 presence of ammonia and some of its salts in urine, which gives 
 that fluid the peculiar properties for which it is used in the dye- 
 house — as a cleansing agent for woollen, and for raising the 
 color of a decoction of logwood. 
 
 Nitrogen also combines with some of the other elements, 
 forming compounds more or less interesting according to their 
 applications, some of which will be noticed when treating of 
 the elements with which these combinations take place. 
 
 Chlorine (CI 35.5). 
 
 Chlorine was discovered by Scheele, in 1774, and was called 
 by him dephlogisticated muriatic acid. About eleven years after 
 this, Berthollet considered that he had found it to be a com- 
 pound of muriatic acid with oxygen, and hence termed it 
 oxygenized muriatic acid — a name which was afterwards con- 
 tracted into oxymuriatic acid. In 1811,* Sir H. Davy discovered 
 it to be a simple or elementary substance, and gave it the name 
 of chlorine, from its having a greenish-yellow color. Chlorine 
 has a very strong, suffocating smell, occasions violent coughing 
 and debility, and gives an astringency to the mouth ; therefore 
 breathing it ought to be avoided as much as possible. 
 
 Chlorine exists in nature in large quantities, in combination 
 with other elements, particularly sodium, forming chloride of 
 sodium (common salt). It is from this 'source that it is pre- 
 pared for use in the arts. If we mix about 3 parts of salt with 
 2 parts of black oxide of manganese, and add to this about 3 
 parts of sulphuric acid, a portion of the oxygen of the manga- 
 nese combines with the sodium, and the chlorine is set at liberty. 
 The action may be thus defined :— 
 
 * In 1809, by Gay Lussac and Thenard. — Ed. 
 
HYPOCHLOEIC ACID. 
 
 69 
 
 Ci Na, Mn 0 2 , 2S0 4 H=S0 4 Mn, S0 4 NA, 2HO, CI. 
 
 <n a (Chi Chlorine Gas. 
 
 Common Salt, j godium 
 
 Peroxide \ ^n.;.;.. \ Water 
 
 Manganese, | Q Water. 
 
 2 proportions ! S0 4 \ Sulphate Soda. 
 
 Salphurie Acid, j H ' \ 
 
 [ S0 4 A Sulphate Manganese. 
 
 Chlorine combines with almost all the elements, and forms 
 with >thern a series of compounds as numerous as they are 
 important. Its power of combining with, and decomposing, 
 coloring substances is remarkable, and has given it a promi- 
 nent standing in the arts. It combines with oxygen in various 
 proportions, giving origin to several compounds, both useful 
 and interesting to the dyer. These, as the following list shows, 
 have all acid properties : — 
 
 Hypochlorous acid . . . . CI 0. 
 
 Hypochloric acid . . . . CI 0 4 . 
 
 Chloric acid CI 0 5 . 
 
 Hyperchloric acid . . . . CI 0 7 . 
 
 Hypochlorous Acid. — This is a very unstable compound, 
 supposed to be connected with many of the operations of bleach- 
 ing. It may be prepared by diffusing some red oxide of 
 mercury in a little water, and then introducing it into a bottle 
 previously filled with chlorine gas. The chlorine is rapidly 
 absorbed, and combines with both the mercury and oxygen. 
 It produces, with the former, an insoluble oxychloride, and 
 with the latter it forms hypochlorous acid, which is in solution 
 in the water. This solution has a yellow color, smells like 
 chlorine, and bleaches powerfully ; but it cannot be kept for 
 any length of time, even in the cold, but passes into chloric 
 acid. Hypochlorous acid combines with alkaline bases, and 
 forms hypochlorites, which also possess bleaching powers. It 
 is generally supposed that when chlorine gas is passed through 
 solutions of the alkalies, such as potash and soda, a similar 
 decomposition takes place as that described of the oxide of 
 mercury, and that hypochlorite of the alkali is the bleaching 
 salt formed. This salt is decomposed by heat. 
 
 Hypochloric Acid may be prepared by adding strong sul- 
 phuric acid to chlorate of potash. The process is a dangerous 
 one, and we would not advise any student to try it, especially as 
 neither the acid nor its salts are of any great importance. The 
 acid is a gaseous body of a yellow color; it combines with bases, 
 
70 
 
 HYDROCHLORIC ACID. 
 
 and forms salts termed hypochlorates. These also possess 
 bleaching powers, and are very unstable. 
 
 Chlokic Acid. — This acid is not of any value in a separate 
 form, and is obtained with difficulty ; but it is easil y enough 
 obtained in combination. When chlorine gas is passed through 
 a solution of caustic potash, it is rapidly absorbed. This, by 
 standing some time, or by the application of a little heat, be- 
 comes converted into a mixed salt of chloride of potassium and 
 chlorate of potash. Thus — 
 
 6C1, 6K0=5C1 K, CI O g K. 
 
 The chlorate of potash being less soluble than the chloride, 
 it is easily separated by crystallizing. Chlorate of potash has 
 very strong detonating powers, and should be used with great 
 care by the student, especially when mixing it with any other 
 substance, as these are often explosive. It is extensively used 
 for lucifer matches. We are not aware that this salt is used to 
 a great extent as yet in the dye-house; but from the property it 
 possesses of giving off oxygen easily, it may be made very use- 
 ful in many operations, where oxidation is an object. It is be- 
 coming extensively used in calico print-works. 
 
 Chloric acid combines with other bases besides potash. These 
 compounds were for a long time, and are occasionally still termed 
 hyper -oxy muriates. 
 
 Hyperchloric Acid is formed from the chlorate of potash. 
 It may be obtained in combination with potash, by acting upon 
 the above named salt with nitric acid, and putting the whole 
 afterwards into a small portion of boiling water; on cooling, 
 the hyperchlorate of potash separates in crystals. The acid 
 may be separated from the base by boiling it with fluosilicic 
 acid, when the hyperchloric acid remains in solution. This , * 
 acid, or its salts, has no bleaching properties. It is an interest- 
 ing compound in its chemical relations, but not yet of much 
 importance to the arts. 
 
 Hydrochloric Acid. — Chlorine unites with hydrogen, and 
 forms an important compound, hydrochloric acid (muriatic 
 acid). It is a gaseous substance, very soluble in water, in which 
 state it is used, and has been known since a very early period 
 in history under the names of marine acid, spirit of salt, &c. 
 Hydrochloric acid is easily obtained by the action of sulphuric 
 acid on common salt. It is prepared on the large scale, by 
 pouring vitriol on common salt, in a furnace prepared for the 
 purpose; the fumes passing off are absorbed by water, which 
 thus becomes liquid hydrochloric acid, weak at first, but it is 
 afterwards concentrated by distillation. The reaction going on 
 during the preparation may be thus represented : — 
 
 NaCl S0 4 H=NaS0 4 , CI H. 
 
HYDROCHLORIC ACID. 
 
 71 
 
 The sulphuric acid is generally used in a diluted state, so 
 that there is always a great quantity of watery vapor passing 
 off with the gas. This acid combines with bases, and forms a 
 series of important salts. That from which it is obtained, viz. 
 chloride of sodium, is a good example. It is matter of inquiry, 
 as we have before stated, whether this acid be capable of com- 
 bining with bases, or if it is not decomposed, and water formed 
 along with the chloride of the base. As, for instance, if hydro- 
 chloric acid be added to nitrate of silver, a white precipitate is 
 formed, which, if collected and analyzed, will be found to be 
 composed of chlorine and silver. Ag CI, not H CI and Ag 0, 
 the action having been — 
 
 Nitrate of fN0 6 Nitric Acid. 
 
 Silver. (Ag. ^^^^ 
 
 Hydrochloric f H... -^ >< \^^ 
 
 Acid. 1 01... Chloride of silver. 
 
 But if we dissolve a piece of zinc in hydrochloric acid, and 
 evaporate to dryness, we get a white powder, which, on analysis, 
 will give zinc, chlorine, and water, in single equivalents. The 
 question then is, whether these elements do not arrange them- 
 selves: — 
 
 Water. 
 
 Chloride of Zinc. 
 Forming chloride of zinc with water. 
 
 H — Hydrochloric acid. 
 
 Or as < ><^" 
 
 Zn — ^ Oxide of Zinc. 
 
 Forming Muriate of Zinc. 
 
 We have, at the risk of repetition, introduced this here, 
 knowing that there is confusion in these names among practical 
 men, and have only again to state that all muriates should be 
 properly termed chlorides. Some authors, to make a distinc- 
 tion, call salts that are in union with water, such as the zinc 
 salt above, muriates, and only dry salts, as that of silver, 
 chlorides. The terms, when thus understood, may be used 
 synonymously, so that no confusion need occur on that head. 
 When hydrochloric acid is exposed to the air, it emits white 
 fumes, which is hydrochloric acid gas with a little watery 
 vapor ; hence exposure weakens the acid, and should be avoided 
 as much as possible in the dye-house. This gas, besides, cor- 
 
72 
 
 HYDROCHLORIC ACID. 
 
 rode? rapidly any substance it comes into contact with ; and 
 destroys colors. It is a colorless acid when pure, but exposure 
 to the light renders it of a yellow color; strong sunshine de- 
 composes it, and, of course, should be avoided. 
 
 The common impurities in this acid are iron, sulphuric acid, 
 and sulphurous acid. The iron may be detected by adding to 
 a little of the dilute acid a drop of gallic acid. Sulphuric acid 
 may be detected by adding a solution of chloride of barium 
 to some of the acid diluted with distilled water: which gives 
 a white precipitate with sulphuric acid. If the clear solution 
 filtered from this test be boiled with a little nitric acid, any 
 sulphurous acid will be converted into sulphuric acid, which 
 will be precipitated by the barium, and its presence detected. 
 Different chloride salts, such as common salt, are sometimes 
 added to hydrochloric acid, to give it weight and specific 
 gravity. This admixture may be detected by evaporating a 
 little of the acid in a small porcelain saucer, or on a piece of 
 glass, and seeing if any residue be left. Pure acid should leave 
 nothing; if the residue is of a brown color, it indicates iron. 
 If the acid is found by these tests to be pure, then the specific 
 gravity may be taken to ascertain its strength. The following 
 table will serve as a guide : — 
 
 Acid of Spec. Grav. 
 
 1.20 in 100 parts. Specific Gravity. Muriatic Acid, 
 
 100 1.2000 40.777 
 
 99 1.1982 40.369 
 
 98 .... . 1.1964 39.961 
 
 97 1.1946 39.554 
 
 96 1.1928 39.146 
 
 95 1.1910 38.738 
 
 94 1.1893 38.330 
 
 93 1.1875 37.923 
 
 92 1.1857 37.516 
 
 91 1.1846 37.108 
 
 90 1.1822 36.700 
 
 89 1.1802 36.292 
 
 88 1.1782 35.884 
 
 87 1.1762 ..... 35.476 
 
 86 1.1741 35.068 
 
 85 1.1721 34.660 
 
 84 .... . 1.1701 34.252 
 
 83 1.1681 33.845 
 
 82 1.1661 ..... 33.487 
 
 81 1.1641 33.029 
 
 80 1.1620 32.621 
 
 79 1.1599 32.213 
 
HYDROCHLORIC ACID. 
 
 Acid of Spec. Grav. 
 
 1.20 in 100 parta. Specific Gravity. Muriatic Acid. 
 
 78 1.1578 31.805 
 
 97 1.1557 ..... 31.398 
 
 76 1.1536 30.990 
 
 75 1.1515 30.582 
 
 74 1.1494 30.174 
 
 73 1.1473 29.767 
 
 72 1.1452 29.359 
 
 71 1.1431 28.951 
 
 70 1.1410 28.544 
 
 69 1.1389 28.136 
 
 ' 68 1.1369 27.728 
 
 67 1.1349 27.321 
 
 66 1.1328 26.913 
 
 65 1.1308 26.505 
 
 64 1.1287 26.098 
 
 63 1.1267 25.690 
 
 62 1.1247 25.282 
 
 61 1.1226 24.874 
 
 60 1.1206 24.466 
 
 59 1.1185 24.058 
 
 58 1.1164 23.650 
 
 57 1.1143 23.242 
 
 56 1.1123 22.834 
 
 55 1.1102 22.426 
 
 54 1.1082 22.019 
 
 53 1.1061 21.611 
 
 52 1.1041 21.203 
 
 51 1.1020 20.796 
 
 50 1.1000 20.388 
 
 49 1.0980 19.980 
 
 48 1.0960 19.572 
 
 47 1.0939 19.165 
 
 46 1.0919 18.757 
 
 45 1.0899 18.349 
 
 44 1.0879 17.941 
 
 43 1.0859 17.534 
 
 42 1.0838 17.126 
 
 41 .... . 1.0818 16.718 
 
 40 1.0798 16.310 
 
 39 1.0778 15.902 
 
 38 1.0758 15.494 
 
 37 1.0738 ..... 15.087 
 
 36 1.0718 14.679 
 
 35 1.0697 14.271 
 
74 
 
 CHLORIDE OF NITROGEN". 
 
 Acid of Spec. Grav. 
 
 1.20 in 100 parts. Specific Gravity. Muriatic Acid. 
 
 34 1.0677 13.-62 
 
 33 1.0657 ..... 13.456 
 
 32 1.0636 13.049 
 
 31 1.0617 12.641 
 
 30 1.0597 12.233 
 
 29 1.0577 11.825 
 
 28 1.0557 11.418 
 
 27 1.0537 11.010 
 
 26 1.0517 10.602 
 
 25 1.0497 10.194 
 
 24 1.0477 9.786 
 
 23 1.0457 9.379 
 
 22 1.0437 8.971 
 
 21 1.0417 8.563 
 
 20 1.0397 8.155 
 
 19 1.0377 7.747 
 
 18 1.0357 7.340 
 
 17 1.0337 6.932 
 
 16 ..... . 1.0318 6.524 
 
 15 1.0298 6.116 
 
 14 1.0279 ..... 5.709 
 
 13 1.0259 5.301 
 
 12 1.0239 4.893 
 
 11 1.0220 4.486 
 
 10 1.0200 4.078 
 
 9 1.0180 3.670 
 
 8 1.0160 3.262 
 
 7 1.0140 2.854 
 
 6 1.0120 2.447 
 
 5 1.0100 2.039 
 
 4 1.0080 1.931 
 
 3 1.0060 1.224 
 
 2 1.0040 0.816 
 
 1 1.0020 0.408 
 
 Chloride of Nitrogen. — Chlorine combines with nitrogen 
 to form NC1 3 , which is one of the most explosive compounds 
 known. It is a heavy liquid substance, and, from its dangerous 
 properties, cannot be of any use to the dyer. 
 
 Chlorine also combines with some of the other non-metallic 
 elements, such as phospborus, sulphur, carbon, &c, and forms 
 compounds, some of which are interesting in a chemical point 
 of view, but not in respect to their practical use in the dye- 
 house. The chlorides of the metals, however, are some of them 
 
BLEACHING. 
 
 75 
 
 important, and will be described as they occur, under the 
 metals. 
 
 The great use of chlorine in the dye-house is as a bleaching 
 agent — into the consideration of which we will now enter a 
 little more in detail. 
 
 While treating of light (p. 25), we had occasion to notice 
 the necessity of goods being a pure white previous to being 
 dyed any light fancy* shade ; otherwise, the natural yellow color 
 of the goods, whether cotton, silk, or woollen, would interfere 
 with the particular shade wanted. If, for example, the shade 
 required be a light pink upon cotton, and a little safflower, the 
 stuff used for dyeing pink, be put upon it, unbleached, the 
 resulting color would not be a pink, but a shade intermediate 
 between a salmon and a brick color, from the yellow ray re- 
 flected from the cotton mixing with the red reflected from the 
 dye. We must, therefore, before dyeing a light pink, get rid of 
 these yellow rays, and this is effected by the process of bleach- 
 ing. Hence, the dyer must, of necessity, be also a bleacher. 
 
 Where and when the practice of bleaching cloth first began, 
 we have no account ; but we may reasonably suppose that, as 
 soon as man became so far civilized as to manufacture clothing, 
 the constant exposure of that clothing to the atmosphere, and 
 occasional washing, would naturally suggest the idea of bleaching. 
 However, we know that bleaching is of very ancient origin, 
 mention being made of it in the oldest books extant. What 
 was the nature of the process practised in those early times is 
 not clear ; but from the earliest description to the close of last 
 century, no other process was known but alternate boiling, and 
 exposure to the atmosphere, a process which required a num- 
 ber of months to complete ; but, since the application of chlo- 
 rine to this purpose, an application which, as Professor Graham 
 observes, "is one of the most valuable which chemistry has 
 presented to the arts," the process is completed in a few days ; 
 nay, for the most of dyeing operations, in a few minutes. 
 
 As many are now unacquainted with the routine of the pro- 
 cess of bleaching previous to the introduction of chlorine, it 
 may be worth while to give a short description of it, to illus- 
 trate the advantages obtained from the application of science 
 to the arts. The first operation was that of steeping, which 
 was merely immersing the yarn in hot water or cold alkaline 
 lyes. When water was used, the steeping lasted for three or 
 four days, but with alkaline lyes forty-eight hours were suffi- 
 cient ; the goods were then washed, and boiled in an alkaline 
 
 * This is a technical term for fugitive colors, or colors not fast. 
 
76 
 
 BLEACHING. 
 
 lye for four or five hours ; washed and exposed on the grass for 
 two or three weeks ; again boiled or bucked, which is a techni- 
 cal term for boiling; washed and crofted, a technical term for 
 exposing on the grass, as before. These alternate operations of 
 bucking, washing, and crofting, were generally repeated four or 
 five times, each time reducing the strength of the alkaline lyes 
 in which the bucking was performed. 
 
 The next process was that of souring, which till nearly the 
 middle of the last century, consisted in steeping the goods for 
 several weeks in soured butter-milk. This process was much 
 shortened by Dr. Home, who suggested the use of sulphuric 
 acid (vitriol) instead of milk ; and twelve hours, with a sour 
 of this acid, were sufficient.* After the first souring, the opera- 
 tions of boiling, washing, souring, and crofting were repeated in 
 regular rotation, until the yarn came to a good color, and was 
 considered perfectly clear. A quantity of soap was generally 
 used in the last operations of boiling. The number of times 
 these operations were repeated varied according to the quality 
 of the goods; linen was seldom finished in less than six months, 
 and cotton goods varied from six weeks to three months. 
 
 Various opinions were advanced to explain the nature of the 
 chemical changes induced during these operations; but such 
 opinions could be only hypothetical so long as the composition 
 of the atmosphere and of water were not known, two substances 
 which acted a very prominent part in these operations, and also 
 while we were ignorant of the nature of the coloring matter 
 upon the goods, and its composition. We have already given 
 the composition of water and air, but the composition of the 
 coloring matter upon cotton, &c, has not as yet been very accu- 
 rately ascertained. Its properties are neutral, and of a resinous 
 nature, from which, as a general principle, we may safely say, 
 that the neutral is composed of hydrogen and carbon with 
 oxygen; and, from the composition of resinous matters in 
 general, it will be composed of hydrogen and carbon, and soluble 
 in alkalies and water, and therefore mostly all taken out by 
 steeping and boiling. These resinous and coloring matters do 
 not form a part of the cotton but mechanically adhere to it, so 
 that substances may act upon and decompose them without in 
 the least destroying the cotton ; indeed, from a number of expe- 
 riments, cotton is found as strong when deprived of these sub- 
 stances as before. 
 
 In boiling cotton yarn in water alone, it loses considerably 
 in weight ; different qualities of cotton varying in this respect ; 
 fine qualities lose least. From a number of experiments, made 
 
 * Home on Bleaching. 
 
BLEACHING. 
 
 77 
 
 expressly to ascertain this point, and with various qualities of 
 cotton, the average of loss may be taken at 5 per cent, of the 
 weight of the cotton. 
 
 In order to ascertain the chemical changes which take place 
 when goods are bleached in the air, M. Berthollet, finding that 
 those seasons when most dew was deposited, were the most 
 effective upon the color, examined the dew which falls from the 
 atmosphere, and also that which transpires from the grass, and 
 found both to contain a sufficient quantity of oxygen to destroy 
 the color of turnsole or litmus paper.* What errors led to these 
 results we do not know, for although dew did contain oxygen, 
 it would not give it acid properties to redden turnsole paper. 
 Or whether M. Berthollet considered the bleaching property of 
 dew owing to its having free oxygen, or to this acid property, 
 we do not know, not having seen the original details. Gould 
 we suppose the formation of peroxide of hydrogen (page 58), 
 the effects would be easily explained.f The theory of croft 
 bleaching has been explained variously as follows: — 
 
 1. The oxygen of the atmosphere combines with the color- 
 ing matter of the cotton, forming a new substance capable of 
 solution in water or alkalies, and comes off by washing or 
 boiling; or it combines with some of the elements of the color- 
 ing matter, such as the carbon, forming carbonic acid gas, which 
 escapes into the air, or with the hydrogen, and forms water; 
 those elements which are left, form either colorless substances, 
 or substances soluble in the next operation. 
 
 2. The oxygen combines directly with the coloring matter, 
 forming a permanent and colorless oxide. 
 
 3. The water acts otherwise than being merely a solvent; 
 that it, or one of its elements, combines with the coloring sub- 
 stance producing the effects noticed in the first proposition. 
 Hence dew being pure and free from any admixture which 
 might retard this union, is better fitted for bleaching; conse- 
 quently, in seasons when most dew is deposited, the bleaching 
 process will be accelerated. Which of these theories is the true 
 one, we cannot say ; but we know that light facilitates the process 
 of bleaching, and this circumstance, we think, favors the sup- 
 position of the coloring matter being decomposed. Other in- 
 teresting theories might be advanced from phenomena observed 
 during the process of croft bleaching ; and also the part that 
 boiling in alkali and the sours take in the operation. 
 
 The modern process of bleaching, and that which is now 
 almost universally practised, is by means of chlorine. This 
 substance, as has been mentioned (page 68), was discovered by 
 
 * Parke's Chemical Essays. 
 
 f See Ozone. 
 
78 
 
 BLEACHING. 
 
 Scheele, who also described its peculiar property of destroying 
 vegetable coloring matters ; but M. Berthollet was the first who 
 called the attention of the public to its value as a bleaching 
 agent, in 1785. About the time this chemist was prosecuting 
 his inquiries into the nature of this substance, he was visited 
 by the celebrated James Watt, to whom Berthollet related the 
 results of his experiments upon bleaching, and from this cir- 
 cumstance the inventor of the modern steam-engine became 
 also the introducer of the new process of bleaching into this 
 country.* 
 
 The introduction of chlorine, as a bleaching agent, like all 
 other discoveries which tend to overturn old practices, met 
 with a host of opposition. The most prominent objections 
 offered were, that it destroyed the cloth, did not give a perma- 
 nent white, and that it killed the men who wrought with it. 
 These statements were not altogether groundless, but the force 
 with which they were urged hastened improvements, and 
 effected remedies. The first method of using chlorine was by 
 saturating cold water with the gas, the water taking up about 
 twice its volume of it. The goods were put into this water, 
 after which it was heated to drive off the chlorine, or set it free 
 that it might act upon the coloring matter ; but, the goods being 
 impaired by this process, even when the greatest care was taken, 
 suggested the diluting of the chlorine water; which diluted 
 liquor was found to bleach equally well, and the goods were 
 preserved. The defect of the goods becoming yellow after a 
 few days, suggested alternate boiling with alkaline lyes ; and 
 the difficulty arising from the workmen being unable to endure 
 the effects of the escaping gas, led to the discovery that alkalies 
 not only absorb a greater quantity of chlorine than water, but 
 that they hold it with greater affinity, not allowing the gas to 
 escape and affect the atmosphere, at the same time parting 
 with it more regularly and effectively to the goods. The alka- 
 lies used were soda and potash, and each bleaching- work had 
 its regular apparatus of retorts and carboys, or wooden chests, 
 for the purpose of making their own chloride of potash or 
 soda. This practice is still continued in many print-works, 
 both in Scotland and England, for particular fabrics or delicate 
 operations, as it is considered much safer and better adapted 
 for certain purposes than the common bleaching powder. In 
 the year 1798, Mr. Tennant, of Glasgow, patented a process for 
 using a solution of lime for absorbing the chlorine instead of 
 potash and soda; shortly after, the hydrate of lime (slaked 
 
 * Some give this honor to Professor Copland, of Aberdeen ; but, from the 
 evidence we have seen, it belongs to Watt, although the difference of time 
 was but little. 
 
BLEACHING. 
 
 79 
 
 lime) was substituted for lime-water, and this is the preparation 
 now used for bleaching, under the names of bleaching powder 
 and chloride of lime. Other minor improvements have been 
 made regarding the quantity of chlorine absorbed by the lime 
 under certain conditions, which will be noticed afterwards. 
 
 Notwithstanding all these discoveries and applications, the 
 real nature of the decoloring agent was still unknown ; it was 
 prepared by digesting together a mixture of common salt, per- 
 oxide of manganese, and sulphuric acid. A decomposition took 
 place, which was explained as follows : The sulphuric acid com- 
 bined with the soda of the salt and set the muriatic acid, which 
 was in union with the soda, at liberty. The oxide of manga- 
 nese gave off a part of its oxygen, which combined with the 
 free muriatic acid and formed oxygenated muriatic acid, a name 
 which was first applied to this new substance ; but after being 
 introduced into the arts, this name was considered too unwieldy 
 for common use, and was therefore contracted into oxy -muriatic 
 acid. It was ultimately contracted, by the workmen into oxygen, 
 and notwithstanding the discovery of Sir H. Davy, in 1811, 
 that oxy-muriatic acid was not common muriatic acid with 
 more oxygen, but a simple body which he called chlorine, the 
 name oxygen is still given to bleaching powder and all its 
 preparations. This is a serious evil to the workmen } not 
 practically, but for their own understanding ; as it identifies 
 chlorine with oxygen, a substance which effects reactions in the 
 operation of dyeing, quite distinct from that with which it is 
 identified. We still remember the difficulty we were in, when 
 hearing that it was the oxygen of the air that supported life, 
 and that it was the same oxygen which turned the green color 
 of the goods while in the vat to blue when exposed to the 
 atmosphere, and at the same time, seeing bleaching liquor, 
 which was also termed oxygen, destroying blues, and felt that 
 we could not breathe its gas but with the greatest difficulty. 
 To solve this puzzle, every chemical book we could find was 
 examined for remarks on oxygen ; but, to our mortification, 
 not one of these works alluded to its bleaching properties. We 
 doubt not but many others have been in the same dilemma. 
 The following order will show our chemical friends the ridicu- 
 lous position in which dyers and bleachers place themselves by 
 retaining such names: — 
 
 "Glasgow, . 
 
 "Messrs. * * Will please send, at their earliest conve- 
 nience, a cask of their strongest oxygen, containing as near 
 as possible 2 cwt. ; let it be newly made and dry ; the last was 
 damp, so that in a few days it became like as much clay, and 
 
80 
 
 BLEACHING POWDER. 
 
 lost the most of its strength. Your attention will oblige yours," 
 &c. &c. 
 
 The dyer will do well to turn to the article oxygen, and 
 peruse it, and then the absurdity of the above order will be 
 observed. 
 
 We are informed that chemic is a common name for bleach- 
 ing liquor in many print-works ; and there are many names 
 for other substances equally unsuitable. We will give a table 
 of these technical terms with their proper designations in 
 another part of the volume. In the mean time, we state that 
 there is no better name for the substance we have been de- 
 scribing than bleaching powder, or, if in solution, bleaching 
 liquor. 
 
 Bleaching powder is prepared by exposing the hydrate of 
 lime (slaked lime) tp an atmosphere of chlorine gas till the lime 
 ceases to absorb the gas. In practice, it is found that when the 
 lime is in combination with an extra equivalent of water, it will 
 absorb much more chlorine than when it has just as much 
 water as slakes it. The chlorine is passed into large vessels or 
 chambers furnished with shelves, upon which the lime is placed. 
 Bleaching powder is white and pulverulent ; it has a hot, bitter, 
 and astringent taste, and a peculiar smell. When digested in 
 water, carbonate of lime and some other impurities remain. 
 
 Some of the continental chemists first suggested that the 
 chlorine was not merely absorbed and retained by the lime, but 
 that it combined with it, and formed one'or more definite com- 
 pounds. This has led to a great deal of research, but scarcely 
 to any definite conclusions, as there are various compounds of 
 chlorine with oxygen, which may be formed during the pre- 
 paration of bleaching powder, and which possess bleaching 
 properties as well as the chlorine alone. The most general sup- 
 position is, that hypochlorite of lime is formed, and that on this 
 salt, and its decomposition, depend the operations of bleaching. 
 This opinion is well founded, and may be taken as expressing 
 the true composition of bleaching powder, which is therefore to 
 be regarded as a definite salt of lime and hypochlorous acid, 
 with chloride of calcium and hydrate of lime;* thus, CaOOlO-f 
 CaCl + CaOHO. 
 
 The best bleaching powder of commerce seldom contains 
 above thirty per cent, of chlorine available in bleaching ; but 
 there are few of the substances employed by the dyer or 
 bleacher more liable to change ; indeed, from its first formation, 
 
 * Whoever is desirous of entering into the merits of the researches made 
 upon the chemical character of bleaching powder, will find a series of valua- 
 ble papers upon the subject, by Balard, in the second volume of the General 
 Records of Science. * 
 
BLEACHING POWDER. 
 
 81 
 
 there seems to be a constant chemical action going on between 
 the chlorine and the lime ; oxygen is disengaged, and chloride 
 of calcium formed, a substance which possesses no bleaching 
 properties. These changes may be much retarded by keeping 
 the powder perfectly dry, or by dissolving it in cold water, and 
 keeping the solution excluded from the air. Chloride of lime 
 (bleaching powder) does not attract moisture from the atmos- 
 phere, as is supposed by dyers ; but, when exposed, it is rapidly 
 changed into chloride of calcium, a substance that is very deli- 
 quescent, and allowing that the lime previously contained two 
 atoms of water, these combine with the chloride of calcium, 
 when formed, and place this salt in the best circumstances for 
 attracting more water from the air, thus hastening the destruc- 
 tion of the remaining chloride of lime. We have seen good 
 bleaching powder by a little inattention reduced to this state 
 in a few weeks, and its bleaching properties almost totally 
 destroyed. 
 
 As chloride of lime loses its bleaching properties by standing 
 and several other circumstances, it is of the utmost consequence 
 to the consumer that he should have some means of determining 
 its real value, both for the sake of safety and accuracy in his 
 processes, and its commercial worth. We have seen bleaching 
 powder, which did not contain above ten per cent, of chlorine, 
 charged and paid for at the same rate as that which contained 
 thirty per cent.; but not having the means of testing it pre- 
 viously, the quality was not discovered till the salt was in solu- 
 tion ; indeed, we are not aware of any relative prices according 
 to the quality of this article, although with a very little care 
 and trifling expense the dyer may know the value of the article 
 he is about to purchase, and of course only pay accordingly. 
 The first method of determining the value of bleaching powder 
 was by sulphate of indigo, but the indigo solution alters by 
 keeping, and is therefore objectionable. u Several exact 
 methods," says Graham, in his Elements of Chemistry, "of which 
 that in which sulphate of iron is used appears to be entitled to 
 preference. This method is based upon the circumstance that 
 the chlorine of chloride of lime converts a salt of the protoxide 
 into a salt of the peroxide of iron. It is found by experience 
 that ten grains of chlorine are capable of peroxidizing 78 grains 
 of crystallized sulphate of iron. In an experiment to determine 
 the percentage of chlorine in a sample of bleaching powder, 
 some good crystals of protosulphate of iron (copperas) are to be 
 pounded and dried by pressing between folds of cloth ; 78 
 grains are dissolved in about two ounces of water, acidulated 
 by a few drops either of sulphuric or muriatic acid ; then 50 
 •grains of the chloride of lime to be examined, are dissolved in 
 t5 
 
82 
 
 BLEACHING POWDEK. 
 
 about two ounces of water, by rubbing them together in a 
 mortar, and the whole poured into a vessel graduated into a 
 hundred parts. The common alkalimeter will do. This is a 
 straight glass tube, or generally a very narrow jar about five- 
 eighths of an inch in width, and 14 inches high, mounted upon 
 a foot, as shown in the accompanying figure, capable at least 
 of containing a thousand grains of water, and graduated into a 
 hundred parts. The jar containing the 50 
 Fig. 6, grains of chloride of lime is filled up to the 
 
 highest graduation by the addition of water, 
 and the whole is well mixed. The clear part 
 of this solution is gradually poured into the 
 solution of sulphate of iron, till the latter is 
 completely peroxidized. This is known by 
 means of red prussiate of potash, which gives 
 a blue precipitate with the protoxide, but not 
 with the peroxide of iron. A white plate of 
 porcelain or glass is spotted over with small 
 drops of the prussiate; a drop of iron solu- 
 tion is mixed with one of these after every 
 addition of chloride of lime ; and the additions 
 continued so long as the prussiate drops are 
 colored blue. They may be colored green, but 
 that is of no moment. When the iron is per- 
 oxidized, the number of graduations or measures of chloride of 
 lime required to produce that effect is noted ; the quantity of 
 chlorine in the 50 grains of bleaching powder is now known, 
 being ascertained by proportion. Thus, if it requires 68 mea- 
 sures of the bleaching solution, then, as 68 is to 10, so 100 is to 
 14,7, the chlorine in the fifty grains of powder; this being 
 multiplied by two gives the percentage of chlorine in the sam- 
 ple, which is 29.4." We have found in operating in this way, 
 a liability to lose a little chlorine as gas. This is obviated by 
 having the iron solution in a stoppered bottle, and upon every 
 addition of bleaching liquor to put in the stopper and shake the 
 bottle. 
 
 Another process has been recommended by Gay-Lussac, 
 which combines simplicity with accuracy, and is coming into 
 general use with the manufacturers of bleaching powder. A 
 solution of arsenious acid is made in muriatic acid, and diluted 
 with water. On adding a solution of chloride of lime, the 
 muriatic acid takes the lime ; the chlorine decomposes the 
 water, combining with its hydrogen, while the oxygen unites 
 with the arsenious acid, and converts it into arsenic acid. 
 When the arsenious solution is tinged with sulphate of indigo, 
 and bleaching liquor added, there is no change taking place on 
 
BLEACHING POWDER. 
 
 83 
 
 the indigo until the whole arsenious acid is transformed into 
 arsenic acid ; but the first drop after this discolors the indigo. 
 The correctness of this test is founded upon the knowledge of 
 what proportion of chlorine is necessary to oxidize the arsenious 
 acid in the test solution. Various proportions have been pro- 
 posed as the standard strength of the solution, but it does not 
 matter much what proportions are used, provided the operator 
 knows what proportion of chlorine is necessary to transform it, 
 and being careful always to have it the same. The best pro- 
 portions for general use are those that require the least calcu- 
 lation. The following proportions we have found to do very 
 well/and to be easily counted: Take one ounce of arsenious 
 acid (common arsenic of the shops), and dissolve it by diges- 
 tion for a few minutes at a boiling heat, in 24 ounces by mea- 
 sure of pure muriatic acid, then add 46 ounces by measure of 
 distilled water; bat in case of any loss by evaporation during 
 digestion, it is better to have a vessel which contains up to a 
 certain mark 70 ounces, and when the acid solution is put into 
 it, to fill up to the mark with water. This may be bottled and 
 put past as the standard test liquor. Every three ounces by 
 measure of it are equivalent to twenty-five grains of chlorine. 
 When a sample of bleaching powder is to be tried, two hun- 
 dred grains are carefully weighed and dissolved in the manner 
 already described, in twice as much water as will fill the alkali- 
 meter, or any other vessel graduated into a hundred parts. 
 Three ounces of the arsenious solution are measured out and 
 put into a glass jar or tumbler, and tinged with sulphate of 
 indigo. The alkalimeter is now filled with the bleaching liquor, 
 which is added slowly to the arsenious solution, stirring con- 
 stantly, and watching every drop that is added for the decolor- 
 ing of the indigo. If the sample be so poor in chlorine that 
 one measure of the alkalimeter will not change the color of 
 the indigo, it may be filled again, and the process continued 
 till the indigo is decolored, and the whole number of gradua- 
 tions taken to effect this carefully noted; the fewer the num- 
 ber of graduations required, the richer the sample is in chlorine. 
 Now, as every three ounces of the test liquor contain arsenious 
 acid equivalent to 25 grains of chlorine, if the hundred mea- 
 sures effect the change of the arsenious into the arsenic acid, 
 the value of the sample is exactly 25 per cent. ; in other words, 
 every four graduations taken to effect this change indicate one 
 per cent, of chlorine. These equivalents were practically de- 
 termined, and may differ a little from the theoretical calculation 
 by atomic numbers, but the difference does not vary above 
 half a per cent., and is not of much consequence in practice. 
 
84 
 
 BLEACHING POWDER. 
 
 The following table will serve as a 'guide to those who may 
 adopt oar proportions : — 
 
 Mea- 
 
 Per cent. 
 
 Mea- 
 
 Per cent. 
 
 Mea- 
 
 Per cent. 
 
 Mea- 
 
 Per cent. 
 
 sures. 
 
 
 sures. 
 
 
 sures. 
 
 
 sures. 
 
 
 150 
 
 16.66 
 
 • 127 
 
 19.68 
 
 104 
 
 24.03 
 
 81 
 
 30.86 
 
 149 
 
 16.77 
 
 126 
 
 19.84 
 
 103 
 
 24.27 
 
 80 
 
 31.24 
 
 148 
 
 16.89 
 
 125 
 
 20.00 
 
 102 
 
 24.51 
 
 79 
 
 31.64 
 
 147 
 
 17.00 
 
 124 
 
 20.16 
 
 101 
 
 24.75 
 
 78 
 
 32.05 
 
 146 
 
 17.12 
 
 123 
 
 20.32 
 
 100 
 
 25.00 
 
 77 
 
 32.46 
 
 145 
 
 17.24 
 
 122 
 
 20.49 
 
 99 
 
 25.25 
 
 76 
 
 32.89 
 
 144 
 
 17.36 
 
 121 
 
 20.66 
 
 98 
 
 25.40 
 
 75 
 
 33.33 
 
 143 
 
 17.48 
 
 120 
 
 20.83 
 
 97 
 
 25.77 
 
 74 
 
 33.78 
 
 142 
 
 17.60 
 
 119 
 
 21.00 
 
 96 
 
 26.04 
 
 73 
 
 34.24 
 
 141 
 
 17.73 
 
 118 
 
 21.18 
 
 95 
 
 26.31 
 
 72 
 
 34.72 
 
 140 
 
 17.85 
 
 117 
 
 21.36 
 
 94 
 
 26.58 
 
 71 
 
 35.21 
 
 139 
 
 17.98 
 
 116 
 
 21.55 
 
 93 
 
 26.87 
 
 70 
 
 35.71 
 
 138 
 
 18.11 
 
 115 
 
 21.73 
 
 92 
 
 27.17 
 
 69 
 
 36.23 
 
 137 
 
 18.25 
 
 114 
 
 21.93 
 
 91 
 
 27.48 
 
 68 
 
 36.75 
 
 136 
 
 18.38 
 
 113 
 
 22.12 
 
 90 
 
 27.77 
 
 67 
 
 37.31 
 
 135 
 
 18.51 
 
 112 
 
 22.32 
 
 89 
 
 28.08 
 
 66 
 
 37.87 
 
 134 
 
 18.65 
 
 111 
 
 22.52 
 
 88 
 
 28.40 
 
 65 
 
 38.46 
 
 133 
 
 18.79 
 
 110 
 
 22.72 
 
 87 
 
 28.73 
 
 64 
 
 39.09 
 
 132 
 
 18.94 
 
 109 
 
 22.93 
 
 86 
 
 29.06 
 
 63 
 
 39.68 
 
 131 
 
 19.08 
 
 108 
 
 23.14 
 
 85 
 
 29.41 
 
 62 
 
 40.32 
 
 130 
 
 19.23 
 
 107 
 
 23.36 
 
 84 
 
 29.76 
 
 61 
 
 40.98 
 
 129 
 
 19.38 
 
 106 
 
 23.58 
 
 83 
 
 30.12 
 
 60 
 
 41.26 
 
 128 
 
 19.53 
 
 105 
 
 23.81 
 
 82 
 
 30.48 
 
 
 
 The above table includes almost the whole range of per- 
 centage of the bleaching powder of commerce ; but should the 
 dyer meet with any not included in the table, the percentage 
 may be calculated as follows. As the number of measures is 
 to 100, so is 25 to the answer required. Say, for example, the 
 measure is 160— then 160 : 100: : 25 : 15.62. 
 
 Any of the two methods just described may be performed 
 in a few minutes; and in a substance that is liable to such 
 deterioration, it is surely of importance that the purchaser 
 should have some knowledge of the quality of the article he is 
 purchasing, and that the workmen know something of the 
 strength of the substance they are working with. Might not 
 a certain price be fixed for a standard strength of bleaching 
 powder, and to rise and fall according to the percentage of 
 chlorine which it contains, in the same manner as practised 
 with soda ash ? It would at least save much annoyance, and 
 
BLEACHING POWDER. 
 
 85 
 
 the common complaint, " that the last cask was not so good 
 as the former." The average percentage of good bleaching 
 powder varies from 25 to 30 per cent. Were this average 
 fixed at three pence per pound, which has been the constant 
 price of bleaching powder these some years, then that which 
 contains from 20 to 25 per cent, would be 2Jd., and from 15 
 to 20, 2d. per pound, while above 30 per cent, the valuQ ought 
 of course to rise in the same ratio. The adoption of some 
 such plan, we are confident, would be satisfactory to all parties. 
 
 To prepare chloride of lime for bleaching, an aqueous solu- 
 tion is requisite. For this purpose a quantity is put into a 
 large* vessel filled with water, well stirred, and allowed to settle; 
 this is termed the stock liquor. There are no definite propor- 
 tions for making up this vat; every bleacher makes up his 
 stock-vat to a certain strength indicated by Twaddell's hydro- 
 meter; a most fallacious test, as the chloride of calcium, and 
 every other matter which is soluble in water, although it has 
 no bleaching properties, affects the hydrometer. Care should 
 be taken that this stock- vat be protected from the air as much 
 as possible, as the lime absorbs carbonic acid, and the chlorine 
 being set at liberty, occasions considerable loss. This may be 
 illustrated by putting a little of the solution upon a flat plate, 
 and allowing it to stand a few days, when it will be found to 
 have lost its bleaching power altogether. 
 
 The first operation in bleaching cloth is steeping it in a 
 waste lye, or tepid water, for a number of hours, generally 
 over night: this is termed the rot steep: its object is to 
 loosen the paste and dirt that may have adhered to the cloth 
 during its manufacture. This steep ought not to be hotter 
 than bloodheat, otherwise, if oil be upon the cloth, it is not 
 saponified, neither is it so easily taken out after; in all cases 
 when oil is observed, it ought to be taken out by rubbing it 
 with soft soap and cold water previous to putting it into the 
 steep. The goods are thoroughly washed from this steep in 
 the dash-wheel, but if a wheel is not convenient, they are 
 tramped in water, and then washed by rinsing them through 
 water with the hands; they are then ready for the boiler. 
 The boiling lye is made up by taking strong caustic lye (see 
 soda and potash), a quantity equal to about six pounds' weight 
 of alkali to one hundred pounds' weight of cloth, having as 
 much water in the boiler as will allow the goods sufficient play 
 when boiling; they ought to boil for three hours. When 
 goods are for light delicate colors, such as Prussian blues, the 
 success of a bleach for such colors depends much upon a good 
 boil. The goods are well washed from the boil, and allowed 
 to drain ; the draining is facilitated by pouring hot water 
 
86 BLEACHING POWDER. 
 
 upon them; they are then hanked up, taking out all the 
 twists, and laid into the bleaching liquor as loose as possible. 
 The vessels which contain this liquor are large, made either of 
 stone or wood, and are termed bleaching- vats, or troughs. To 
 prepare this liquor, these troughs are filled with water, and 
 a quantity of the stock liquor added until the 
 Fig. 7. required strength is obtained, which is indicated 
 
 by its action upon the sulphate of indigo, in 
 what is termed the test-glass, a vessel of this 
 form. It is filled to the mark a with the sul- 
 phate of indigo; this indigo is generally sup- 
 plied by the manufacturers of the powder as 
 test blue, the liquor is added drop by drop 
 until the color of the indigo is destroyed ; the 
 quantity taken to effect this is denoted by the 
 graduations above; the weaker the liquor, the 
 greater the number of graduations required ; 
 
 each of these graduations is termed its degree ; 
 two degrees are considered a fair strength for light goods, but 
 for heavy fabrics it may be made stronger ; they are allow r ed 
 to steep in this for several hours, varying according to the 
 nature of the goods. The objections we had to the use of sul- 
 phate of indigo as a test in the former case are equally applica- 
 ble here. We have found this test to be very uncertain. A 
 much better method has been adopted by Mr. Walter Crum, a 
 description of which was read by him to the Glasgow Philo- 
 sophical Society, and published in the Report of that Society 
 for 1841. We quote the following important paragraphs of 
 the paper :— 
 
 " Chlorimetry requires to be practised by the bleacher for 
 two purposes — First, he has to learn the commercial value of 
 the bleaching powder which he purchases; and with that view 
 he can scarcely desire anything better than the method either • 
 by arsenious acid or green copperas. But the more important, 
 because the hourly testing of his bleaching liquor, and that on 
 which the safety of his goods depends, is the ascertaining the 
 strength of the weak solutions in which the goods have to be 
 immersed. If the solution is too strong, the fabric is apt to be 
 injured. If too weak, parts of the goods remain brown, and 
 the operation must be repeated. The range within which 
 cotton is safe in this process is not very wide. A solution 
 standing 1° on TwaddelPs hydrometer (spec. grav. 1.005), is 
 not more than safe for such goods, while that of half a degree 
 is scarcely sufficient for the first operation on stout cloth, unless 
 it is packed more loosely than usual. When the vessel is first 
 set with fresh solution of bleaching powder, there is little diffi- 
 
BLEACHING POWDER. 
 
 87 
 
 culty, if the character of the powder be known ; but when the 
 goods are retired from the steeping vessels, they leave a por- 
 tion of bleaching liquor behind, unexhausted, which must be 
 taken into account in restoring the liquor to the requisite 
 strength for the next parcel. The chlorimeter must, therefore, 
 be applied every time that fresh goods are put into the liquid. 
 It must, consequently, be intrusted to persons who may not be 
 expert either in figures or in chemical manipulation. Hence 
 all the processes I have described are too delicate and tedious. 
 
 "I introduced another into our establishment some years ago, 
 which has been in regular use ever since, and by which the 
 testing is performed in an instant. It depends on the depth of 
 color of the peracetate of iron. A solution is formed of proto- 
 chloride of iron, by dissolving cast-iron turnings in muriatic 
 acid of half the usual strength. To insure perfect saturation, 
 a large excess of iron is kept for some time in contact with the 
 solution at the heat of boiling water. One measure of this 
 solution, at 40° Twaddell (spec. grav. 1.200), is mixed with one 
 of acetic acid, such as Turnbull & Co., of Glasgow, sell at 8s. a 
 gallon. That forms the proof solution. If mixed with six or 
 eight parts of water it is quite colorless, but chloride of lime 
 occasions with it the production of peracetate of iron, which 
 has a peculiarly intense red color. 
 
 "A set of phials is procured, 12 in number, all of the same 
 diameter. A quantity of the proof solution, equal to ^th of 
 their capacity, is put into each, and then they are filled up 
 with bleaching liquor of various strengths, the first at x^th of 
 a degree of Twaddell, the second, T 2 oths, the third, T 3 2ths, and 
 so on up to jf ths, or one degree.^ They are then well corked 
 up, and ranged together, two and two, in a piece of wood, in 
 holes drilled to suit them. We have thus a series of phials 
 showing the shades of color which those various solutions are 
 capable of producing. To ascertain the strength of an un- 
 known and partially exhausted bleaching liquor, the proof 
 solution of iron is put into a phial similar to those in the instru- 
 ment, up to a certain mark, ^th of the whole. The phial is 
 then filled up with the unknown bleaching liquor, shaken, and 
 placed beside that one in the instrument which most resembles 
 it. The number of that phial is its strength in 12ths of a 
 degree of the hydrometer; and by inspecting the annexed 
 table, we find at once how much of a solution of bleaching 
 powder, which is always kept in stock, at a uniform strengh of 
 6 degrees, is necessary to raise the whole of the liquor in the 
 steeping vessel to the desired strength. 
 
 " The instrument is formed of long 2-ounce phials cast in 
 a mould; those of blown glass not being of uniform diameter. 
 The outside, which alone is rough, is polished by grinding, 
 
88 
 
 BLEACHING POWDER. 
 
 CO 
 
 ft 
 
 Fig. 8. 
 
 a 42 
 
 £5r \J/fOi UiUi td}t=j? &i 
 
 and in this state they 
 can easily be procured 
 at 4s. 6d. a dozen. They 
 are placed two and two, 
 so that the bottle con- 
 taining the liquid to be 
 examined may be set 
 by the side of any one 
 in the series, and the color compared by looking through the 
 liquid upon a broad piece of white paper stretched upon a 
 board behind the instrument.* 
 
 "To explain the table, it is necessary to state that the steep- 
 ing vessels we employ contain at the proper height for receiving 
 goods, 1440 gallons, or 288 measures of 5 gallons each — a 
 measure being the quantity easily carried at a time. In the 
 following table, 0 represents water, and the numbers 1, 2, 3, 
 &c., are the strength of the liquor already in the vessel in 12ths 
 of a degree of Twaddell, as ascertained by the chlorimeter. 
 If the vessel has to be set anew, we see by the first table that 
 82 measures of liquor at 6° must be added to (256 measures of) 
 water to produce 288 measures of liquor at T 8 5 ths of a degree. 
 But if the liquor already in the vessel is found by the chlori- 
 meter to produce a color equal to the 2d phial, then 24 mea- 
 sures only are necessary, and so on. 
 
 To stand x 8 2 -° 
 
 0 requires 32 measures. 
 
 1 — 28 — 
 
 2 — 24 — 
 
 3 — 20 — 
 
 4 — 16 — 
 
 5 — 12 — 
 
 6 — 8 — 
 
 7 — 4 — 
 
 To stand T 4 5 ° 
 
 0 requires 16 measures. 
 
 1 — 12 — 
 
 2 — 8 — 
 
 3 — 4 — 
 
 To stand / 2 ° 
 
 0 requires 24 measures. 
 
 1 _ 20 — 
 
 2 — 16 — 
 
 3 — 12 — 
 
 4 — 8 — 
 
 5 — 4 — 
 
 To stand T %° 
 
 0 requires 12 measures. 
 
 1 — 8 — 
 
 2 — 4 — 
 
 * The above figure represents the instrument fitted with tubes, which serve 
 equally well. 
 
BLEACH INTG. 
 
 89 
 
 "Let us see what takes place on mixing chloride of lime 
 with protomuriate of iron. On the old view of the constitu- 
 tion of bleaching powder, that it is a combination of chlorine 
 and lime, we have: — 
 
 the peroxide of iron forming a peracetate with the acetic acid 
 which is present. Or, supposing with Balard that, when two 
 atoms of chlorine unite with two atoms of lime, the product is 
 CaQl + CaO, CIO, we have this formula : — 
 
 3 CaCl ) 
 3 (CaO, CIO) } becoming • 
 12 FeCl ) 
 
 "Here, one third only of the iron goes to form the deep- 
 colored peracetate, while the whole might be employed for that 
 purpose, by using protoacetate instead of protochloride. The 
 latter, however, is preferred, from the greater tendency of the 
 acetate to attract oxygen from the air, and consequently the 
 greater difficulty of preserving it. Even with the chloride it 
 is best to give out small quantities at a time, preserving the 
 stock in well-closed bottles." 
 
 From this description, it will be seen that the method recom- 
 mended by Mr. Crum, may be adopted for testing the percentage 
 of the powder as well as the strength of the liquors. 
 
 To return to the bleaching process. The goods being allowed 
 to steep in the bleaching liquor for some hours, they are lifted 
 and washed, after which, if they are thick stout goods, they are 
 put into a sour for a little while, then washed, and go through 
 the same operations of boiling, liquoring, and souring as before; 
 but, for all common fabrics, we have found it the best practice 
 to sweeten* the goods from the liquor, hank them anew, and put 
 them back into a new liquor of the same strength for a few 
 hours, wash them from this, and allow them to steep for an 
 hour in strong sour of vitriol and water, about 1J pint of the 
 former to four gallons of the latter. 
 
 There is perhaps no single branch connected with the art of 
 dyeing upon which there is more difference of opinion than 
 bleaching. Every one has some peculiarity of his own; but, 
 when the peculiarities are all compared, the difference in gene- 
 ral is only nominal. One thing may be noticed, namety, the 
 necessity of washing the goods well from the liquor before 
 
 * Building the goods on a drainer, and pouring water upon them till the 
 water ceases to taste of liquor as it comes from them, is termed sweetening. 
 
90 
 
 BLEACHING. 
 
 souring, as any lime remaining upon the cloth will be formed 
 into an insoluble sulphate, and resist the dye. Some maintain 
 that this is of no consequence; in our opinion, it depends 
 wholly upon the color which is to be dyed on the cloth. We 
 have found that light pinks, light greens, light lavenders, and 
 sometimes light blues, when not washed well from the liquor, 
 were often full of white spots, which we ascribed to that cause, 
 although there are white spots often occurring both on yarn 
 and cloth from other causes; but, for other dark shades, we 
 found no difference, and for colors to be dyed with the bichro- 
 mate of potash (chrome), such as yellows, ambers, and orange, 
 we seldom gave them any sour, only washed from the first 
 liquor and then dyed * 
 
 Cotton in the hank (yarn), when it is to be finished white, 
 goes through the same process as cloth, with the exception of 
 the rot steep; but, for dyeing, a quicker operation is adopted. 
 All cotton yarn must be boiled in water for three or four hours 
 previous to being dyed. Every lot of ten-pounds' weight, con- 
 stituting what is termed a bundle, is divided into six equal 
 numbers of spindles, and hung upon wooden pins about three 
 feet long and two inches thick ; this is termed sticking. 
 
 The stock liquor for yarn is generally prepared in a cask 
 containing about 120 gallons of water; to this is added about 
 20 lbs. of good bleaching powder, stirred, and allowed to settle. 
 A small tub, of a size in which a bundle is wrought freely, 
 termed a ten-pound tub, is filled nearly two-thirds full with 
 boiling water, and a bucket or pailful (about four gallons) of 
 the stock liquor is added. The bundle is now let down as 
 quickly as possible, and turned over for about ten minutes, 
 after which it is put through a second tub of the same size, 
 with water made a little sour by adding about an imperial gill 
 of vitriol. It is wrought in this for about five minutes. Being 
 then well washed, it is ready to be dyed of almost any light 
 shade. By this method two men can bleach and wash two 
 hundred pounds' weight of yarn in about three hours, a quan- 
 tity which, by the other process of boiling, steeping, and sour- 
 ing, would have occupied two days. 
 
 Having detailed the present method of bleaching cotton goods 
 for dyeing, we may say a little upon the chemical nature of 
 these processes. Previous to the discovery of the elementary 
 nature of chlorine, when that substance was considered a com- 
 pound of muriatic acid and oxygen, it was thought that the 
 
 * In souring fine goods, the vessel used is of consequence. In using a 
 vessel lined with lead, there was experienced for a long time a constant 
 occurrence of small holes in the goods. On changing the vessel for a wooden 
 one, this evil has entirely disappeared. The cause of the holes has not, how- 
 ever, been determined. 
 
BLEACHING. 
 
 91 
 
 acid parted with its oxygen, and that this constituent bleached 
 the goods in the same way as atmospheric air in croft bleaching, 
 but more rapidly. When the true nature of chlorine was dis- 
 covered, the theory was somewhat changed; finding, as was 
 then supposed, that chlorine did not bleach except water was 
 present, it was considered that the chlorine united with the 
 hydrogen of the water forming muriatic acid, and that the 
 liberated oxygen was still the bleaching agent. 
 
 This theory is still maintained and supported by various 
 analogies. We quote the following from Gregory and Liebig's 
 edition of Turner's Chemistry: "One of the most important 
 properties of chlorine is its bleaching power. All animal and 
 vegetable colors are speedily removed by chlorine, and when 
 the color is once destroyed it can never be restored. Davy 
 proved that chlorine cannot bleach except water be present ; 
 thus dry litmus paper suffers no change in dry chlorine, but 
 when water is admitted, the color speedily disappears. It is 
 well known also, that hydrochloric acid (muriatic acid) is 
 always generated when chlorine bleaches. From these facts, 
 it is inferred that water is decomposed during the process, that 
 its hydrogen unites with chlorine, and that decomposition of 
 the coloring matter is occasioned by the oxygen liberated. The 
 bleaching property of binoxide of hydrogen, and of chromic 
 and permanganic acids, of which oxygen is certainly the decol- 
 oring principle, leaves little doubt of the accuracy of the fore- 
 going explanation." 
 
 Another theory has been advanced, and equally if not more 
 tenable, by which the chlorine is supposed to act directly upon 
 the coloring matter. The following is from Sir Robert Kane's 
 Treatise on Chemistry ; " Formerly, it was considered that water 
 was necessary for this bleaching, and that the chlorine combined 
 with the hydrogen, while the oxygen of the water being thus 
 thrown upon the organic substance, oxidized it, and formed a 
 new body, which was colorless. I have shown, however, that 
 this is not the case, but that the chlorine enters into the constitu- 
 tion of the new substance formed, sometimes replacing hydrogen, 
 at others simply combining with the colored body, and in some, 
 the reaction being so complete that its immediate stages cannot 
 be completely traced." 
 
 This theory is also supported by several analogies, such as 
 the action of chlorine upon indigo, already noticed ; but which 
 of the changes, alluded to by Sir Eobert Kane, takes place 
 during the bleaching of cotton, is not yet known. Chloride of 
 lime, says the same author, does not bleach except an acid be 
 present to combine with the lime, and set the chlorine at 
 liberty ; but this is only conditional. It is true that if blue 
 litmus paper be put into a solution of newly dissolved chloride 
 
92 
 
 BLEACHING. 
 
 of lime, it is not bleached; but if the solution be allowed to 
 remain in contact with the air for an hour or two, the lime 
 combines with the carbonic acid of the atmosphere; and if the 
 blue litmus paper be put into .this solution, it is instantly 
 bleached by the liberated chlorine. Cotton that has not been 
 boiled in alkalies, is acted upon as the litmus paper in both 
 cases ; but if the cotton has received a good alkaline boil, and 
 is well washed, the bleaching process goes on, although the 
 bleaching powder be newly dissolved. This shows that the 
 alkaline lyes effect a change upon the coloring matter. The 
 nature of this change, we are not as yet prepared to state ; 
 several opinions have been given, but they are hypothetical, 
 and some of them are not borne out by practice. Neither is 
 the theory of Sir Eobert Kane, of the formation during 
 bleaching of a colorless chloride, or oxide, at all admissible, at 
 least as regards cotton. According to this theory, goods being 
 bleached by having formed upon them a new compound, would 
 become heavier, whereas practice shows that the operation of 
 bleaching causes the goods to lose about 3 per cent, in weight. 
 From several experiments which we made, we found that the 
 loss by boiling was 5 per cent., and by bleaching, 3 per cent., 
 in all 8 per cent. 
 
 Whenever the cloth is put into the bleaching liquor, there 
 are acids formed, the principal of which is the hydrochloric; 
 but whether it is from the chlorine combining with the hydro- 
 gen of the water, or the coloring matter of the goods, we cannot 
 say, the latter we think most probable. Our opinion is, that 
 the chlorine combines with the hydrogen of the coloring 
 matter; and, according to a law we have several times alluded 
 to, the remaining elements of the coloring matter form a new 
 substance, which is soluble, and thus the whole coloring matter 
 is taken off the cloth. In vats, where several hundred pounds' 
 weight of cotton have been bleached before changing the liquor, 
 there is evidence of more substances remaining than merely a 
 solution of muriate of lime; but what these are, we dare not as 
 yet venture to assert. 
 
 The effect of light in the operation of bleaching also favors 
 this hypothesis, for we know that exposure to the sun facilitates 
 the process very much. This circumstance, however, tells in 
 favor of the theory that the oxygen is the bleaching agent, as 
 well as in favor of the theory which makes the chlorine the 
 bleaching agent. There is only this difficulty, which, how- 
 ever, must not be overlooked, namely, that if a solution con- 
 taining chlorine is exposed' to the light, there is a decomposi- 
 tion of the water; for the chlorine combines with the hydrogen, 
 and liberates the oxygen of the aqueous molecule. The oxygen 
 would again, by this theory, require to combine with the 
 
SULPHUR. 
 
 93 
 
 hydrogen of the coloring matter, and form water, a series of 
 affinities which we cannot conceive ; for if the affinity of the 
 chlorine be stronger for the hydrogen than for the oxygen of 
 the water, it would necessarily take the hydrogen from the 
 coloring matter, seeing that oxygen, which by this showing 
 has the weaker power, decomposes it to form water again, a 
 series of reactions altogether irreconcilable with one another. 
 That the oxygen combines with the color, forming a colorless 
 oxide, is quite irreconcilable with the practical fact of the 
 goods losing weight by bleaching. 
 
 Such is an outline of the processes of bleaching cotton goods 
 for* dyeing, as practised in most dye-works at the present day. 
 Woollen and silk are bleached by exposing them, after being 
 boiled or scoured, to the vapor of sulphurous acid, which pro- 
 cess will be noticed under sulphur; but they are not thus 
 bleached for dyeing. 
 
 Ozone. — Within a few years a substance, or property, which 
 has got the name of Ozone, has been discovered to have 
 extraordinary bleaching properties. If a few sticks of phos- 
 phorus be placed in a large bottle containing a little water at 
 bottom, and corked, in a short time the atmosphere of the 
 bottle is found to possess peculiar properties, and is said to 
 contain ozone, and acts in relation to a great many substances 
 the same part as chlorine. Professor C. F. Schonbein, the 
 discoverer of this substance, and who has made it the subject 
 of careful investigation, was able to bleach, or decolor, sulphate 
 of indigo, and also many flowers by means of it. The real 
 character of ozone is as yet only imperfectly understood. The 
 discoverer supposes it to be a volatile peroxide of hydrogen ; 
 and this idea has been to some extent verified by experiments, 
 while others suppose it to be a new condition of oxygen. How- 
 ever, enough is known of it to induce us to think that when 
 easy methods of producing and applying it are discovered, 
 ozone will be found of much value in the arts. 
 
 Sulphur (S. 16). 
 
 Sulphur has been known from the earliest ages. It is found 
 in large quantities, uncombined in the neighborhood of vol- 
 canoes ; and is also extensively diffused through nature in com- 
 bination, especially with metals. It is obtained in great abund- 
 ance by roasting the sulphurets of iron, lead, copper, and zinc. 
 
 Sulphur is a hard, brittle substance, of a greenish-yellow 
 color. It is not soluble in water, and is not changed by ex- 
 posure to the air. When heated to the temperature of 824° 
 Fah., it sublimes, and deposits again in the fine powder well 
 
94 
 
 SULPHUROUS ACID. 
 
 known as the flowers of sulphur. If heated in a close vessel, 
 say a glass flask, to 218° Fah. it melts and becomes liquid as 
 water, but by increasing the heat it undergoes some curious 
 changes; at 340° it begins to get thick, and assumes a reddish 
 color, and if the heat be continued, it becomes so thick that it 
 will not pour from the vessel. At 482° it begins to become 
 thinner, and continues thinning until it boils at 750°. When 
 suddenly cooled from its most fluid state, which is about 224°, 
 by throwing it into cold water, it becomes instantly brittle; 
 but if cooled in the same manner, when thick (about 400°), it 
 remains quite soft, and may be drawn into threads. If heated 
 in the open air to about 300° it takes fire, and burns with a 
 pale blue flame, and gives off most suffocating fumes of sulphur- 
 ous acid gas. 
 
 Sulphur combines with oxygen in several proportions, 
 forming acids of considerable importance in the arts. These 
 are : — 
 
 Sulphurous acid S0 2 
 
 Sulphuric acid S0 3 Anhydrous 
 
 Hyposulphurous acid . . . S 2 0 2 
 Hyposulphuric acid . . . . S 2 0 5 
 
 Sulphurous Acid is a gaseous substance, and is always 
 produced when sulphur is burned in the air, or in oxygen. It 
 may be prepared also from the compounds of sulphur. If 
 sulphuric acid be heated in contact with metallic copper, or 
 charcoal, sulphurous acid is given off. We have : — 
 
 2 S0 4 H and Cu = S0 4 Cu + S0 2 + 2 HO 
 
 If charcoal be used instead of copper in this experiment, car- 
 bonic gas is also liberated. It may also be prepared by heating 
 together 3 parts flowers of sulphur, and 4 parts black oxide of 
 manganese, in a similar apparatus to that described for the pre- 
 paration of oxygen from manganese. 
 
 This gaseous acid, as has been stated, is much used in 
 bleaching animal substances, as silk and woollen ; and also 
 some vegetable substances, as straw. For these operations 
 the gas is procured by merely burning the sulphur in the air. 
 The articles to be bleached are put into a chamber, or box, 
 made as tight as possible, in which is placed a small pan of 
 sulphur, which is kindled by putting into it a piece of redhot 
 iron. The chamber is then closed, and the articles, damp 
 and well spread out, are thus exposed to the sulphurous 
 fumes. The gas is absorbed in the first place, by the water 
 on the goods, and is thus brought into immediate contact, 
 and enabled to combine with the fabric. Goods bleached by 
 this gas are increased in weight, showing a combination; they 
 
SULPHURIC ACID. 
 
 95 
 
 are not permanently white, showing that the compound formed 
 is decomposed; indeed, the gas gradually escapes, and by im- 
 mersing the goods in a stronger acid, the white compound is 
 decomposed. This may be beautifully illustrated by exposing 
 a red rose to the fumes of sulphurous acid gas ; it is bleached 
 white, but by putting it into a sour (vitriol and water), the red 
 color is restored. This shows the distinctive characters of this 
 gas and chlorine, as bleaching agents, and that any analogy 
 drawn between them to support a theory is groundless. Some 
 bleachers of woollen pass the goods through a solution of 
 sulphurous acid in water, instead of stoving them. Bleaching 
 by this gas is not done with goods that are to be dyed. 
 
 Sulphurous acid passes readily into sulphuric acid by ab- 
 sorbing more oxygen. In newly distilled water, or water 
 having no air or oxygen dissolved in it, sulphurous gas may 
 be kept a long time if well corked up, but without these pre- 
 cautions it very soon combines with the oxygen dissolved in 
 the water. If a quantity of peroxide of iron is put into a solu- 
 tion of this gas, it passes into the state of sulphuric acid, and 
 protoxide of iron. The formula is 
 
 Fe 2 0 3 +S0 2 =S0 4 Fe + FeO 
 
 Sulphuric Acid is one of the most important of the com- 
 pounds of sulphur; it is not produced by the direct action of 
 its elements, but generally from the oxidation of sulphurous 
 acid. We mentioned, when treating of nitrogen (page 60), 
 that the binoxide of nitrogen on coming into contact with the 
 air combines with more oxygen, and is converted into the 
 peroxide of nitrogen; and that this compound readily yields 
 its oxygen again toother bodies which have a strong attraction 
 for it. If sulphurous acid is brought into contact with peroxide 
 of nitrogen in the presence of water, a decomposition takes 
 place, and there is formed sulphuric acid and nitrous acid, 
 which may be represented by the formula, 
 
 S0 2 +N0 4 =S0 3 + N0 3 
 
 One proportion of > gQ Crystalline sulphuric acid. 
 
 sulphurous acid i 
 
 One proportion of 
 peroxide nitrogen. 
 
 Nitrous acid. 
 
 Both of these compounds when formed are taken up by the 
 water, the first forming hydrous sulphuric acid, the second is 
 decomposed, every three proportions being resolved into 
 3 N0 3 =2 NO, + N0 5 
 
96 
 
 SULPHURIC ACID. 
 
 (NO.- 
 
 3 proportions of 0... 
 nitrous acid, N0 3 is < N0 3 
 resolved into 0 ... 
 
 n6; 
 
 Binoxide of nitrogen. 
 
 Binoxide of nitrogen. 
 
 Nitric acid. 
 
 The nitric acid remains in the water with the vitriol, but the 
 binoxide of nitrogen rises to the surface and imbibes oxygen, 
 and is again converted into peroxide, ready to undergo again 
 the same changes. On the large scale, these changes and re- 
 actions are brought about by causing the sulphurous acid fumes 
 from burning sulphur, and the peroxide of nitrogen fumes 
 from pouring sulphuric acid upon nitrate of soda or potash, to 
 pass together into large leaden chambers along with a jet of 
 steam. In this chamber the reactions above described go on. 
 At the bottom of this chamber is a layer of water for absorbing 
 the acids formed ; and at the top is an aperture to admit the 
 air and the other gases, so that the binoxide of nitrogen becomes 
 peroxidized as it rises to the top. The water from the bottom 
 is drawn off at short intervals as it becomes impregnated with 
 the acid. These intervals are so arranged that the specific 
 gravity of the acid when drawn off is about 1.600=120° T wad- 
 dell. It is then evaporated in leaden tanks, until the specific 
 gravity becomes about 1.76, or 152° Twaddell. If the operation 
 were continued farther, the acid would act upon the lead ; it is 
 consequently transferred to vessels of glass or platinum, and 
 evaporated until the specific gravity rises to about 1.847, or 
 169i Twaddell. 
 
 The whole of the operation of making sulphuric acid may be 
 done, for illustration, by the simple apparatus on next page. 
 Generate sulphurous acid S0 2 , in one bottle (B), and peroxide 
 of nitrogen N0 4 in another (C), and cause the two gases to 
 meet in a third bottle (A), having a little water at bottom ; the 
 formation of sulphuric acid will go on as described, and be found 
 in the water of the condensing vessel (A) after the operation. 
 
 A great quantity of sulphuric acid is made by burning iron 
 pyrites, a native compound of iron and sulphur. This mineral 
 often contains arsenic, which the sulphurous acid carries with 
 it into the acid chamber ; and therefore the vitriol made from 
 this source contains arsenic as an impurity. 
 
 Sulphuric acid may also be prepared by putting a quantity 
 of sulphate of iron into an earthenware retort, and applying a 
 strong heat to it ; the sulphuric acid is distilled over, and 
 peroxide of iron remains. This is the oldest method of obtain- 
 ing sulphuric acid, and is still practised in some parts of 
 Germany. The acid so obtained is very strong; has a dark 
 color, and gives oft* a quantity of white fumes ; hence it is called 
 fuming sulphuric acid. It is also called Nordhausen acid, from 
 
SULPHURIC ACID. 97 
 
 Fig. 9. 
 
 its being manufactured there. When this acid is poured into 
 cold water, it produces a hissing noise, like that produced by 
 putting a redhot iron into water. This acid is excellently 
 adapted for making sulphate of indigo. 
 
 Sulphuric acid may be mixed with water in any proportion, 
 but there seem to be certain definite quantities with which it 
 will combine with water chemically. When added to water, 
 there is always heat evolved; this heat is a definite quantity, 
 and accompanied by a condensation of bulk, as the dyer may 
 easily convince himself by taking measured quantities of strong 
 vitriol and water, and mixing them; when the mixture is cool, 
 he will find a considerable diminution of bulk. The following 
 experiments upon the amount of condensation, and heat given 
 out, were performed with a common alkali meter and thermo- 
 meter : — 
 
 Measure of 
 water. 
 
 Measure of 
 Acid. 
 
 Heat when 
 mixed. 
 
 Increase of 
 heat. 
 
 Loss by conden- 
 sation. 
 
 90 
 
 10 
 
 86° 
 
 40° 
 
 5 
 
 80 
 
 20 
 
 116 
 
 70 
 
 7 
 
 70 
 
 30 
 
 154 
 
 108 
 
 8 
 
 60 
 
 40 
 
 188 
 
 142 
 
 9J 
 
 50 
 
 50 
 
 210 
 
 164 
 
 11 
 
 40 
 
 60 
 
 212 
 
 166 
 
 11 
 
 30 
 
 70 
 
 200 
 
 154 
 
 9 
 
 20 
 
 80 
 
 164 
 
 118 
 
 8i 
 
 10 
 
 90 
 
 136 
 
 90 
 
 7 
 
 7 
 
98 
 
 SULPHURIC ACID. 
 
 The above is the mean of three trials. The proportions of 
 acid and water were taken to make 100 graduations, and mixed. 
 The heat was observed immediately after mixing, and the mix- 
 ture was kept in a stoppered bottle until cold, when it was 
 measured by the alkalimeter, and the loss by condensation 
 noted. The heat of the water and acid separately was 46°. 
 The acid used was specific gravity 1.795, taken by Twaddell, 
 179°. Another proof that water and sulphuric acid form a 
 definite compound, is, that when the acid has the specific gra- 
 vity of 1.78, the composition is S0 4 H + HO. This, at a tem- 
 perature of 32°, will crystallize in large and regular crystals, 
 while stronger or weaker acid, at the same temperature, will 
 not crystallize. This is a circumstance sometimes experienced 
 in the dye-house, and is commonly taken as an evidence of 
 impurity in the acid, which, however, it is not. 
 
 The ordinary impurities in sulphuric acid are lead, nitric 
 acid, arsenic, and sometimes sulphate of potash, which is added 
 to give it density. The presence of lead is easily detected by 
 diluting a little of the acid with distilled water ; sulphate of 
 lead is not soluble in dilute acid, and when present there is 
 produced a milkiness in the solution, as is often seen in the 
 dye house when the acid is added to water. Nitric acid may be 
 detected, as described, page 66, by suspending a clean crystal 
 of sulphate of iron in the acid, and heating it ; a black ring is 
 then seen, or the smell of peroxide of nitrogen perceived. 
 Sometimes, a little of this peroxide is present in the acid, and 
 either of these impurities is very bad when the sulphuric acid 
 is to be used for indigo, garancine, or any organic substance. 
 Arsenic may be detected by diluting the acid, and passing a 
 current of sulphureted hydrogen through it, which gives a 
 yellow precipitate when arsenic is present. This substance, 
 however, is not deleterious in those operations of the dye-house 
 wherein sulphuric acid is used. Sulphate of potash, or soda, 
 may be detected by putting a few drops of acid into a small 
 basin, and saturating it with ammonia, then evaporating to dry- 
 ness, and continuing a strong heat until all white fumes of sul- 
 phate of ammonia cease; nothing will remain if the acid is 
 pure. 
 
 After ascertaining that the acid is pure, the hydrometer 
 may be used to discover its strength. The following t^ble will 
 be useful in this operation : — 
 
SULPHURIC ACID, 99 
 
 Liquid, 
 acid. 
 
 specific gravity. 
 
 Dry acid oO«j in 
 100 parts. 
 
 .Liquid 
 acid. 
 
 specific gravity. 
 
 Dry acid feOg in. 
 100 parts. 
 
 100 
 
 1.8485 
 
 81.54 
 
 50 
 
 1.3884 
 
 40.77 
 
 99 
 
 1.8475 
 
 80.72 
 
 49 
 
 1.3788 
 
 39.95 
 
 98 
 
 1.8460 
 
 79.90 
 
 48 
 
 1.3697 
 
 39.14 
 
 97 
 
 1.8430 
 
 79.09 
 
 47 
 
 1.3612 
 
 38.32 
 
 96 
 
 1.8400 
 
 78.28 
 
 46 
 
 1.3530 
 
 37.51 
 
 95 
 
 1.8376 
 
 77.46 
 
 45 
 
 1.3440 
 
 36.59 
 
 94 
 
 1.8336 
 
 76.65 
 
 44 
 
 1.3345 
 
 35.88 
 
 93 
 
 1.8290 
 
 75.83 
 
 43 
 
 1.3255 
 
 35.06 
 
 92 
 
 1.8233 
 
 75.02 
 
 42 
 
 1.3165 
 
 34.25 
 
 91 
 
 1.8179 
 
 74.20 
 
 41 
 
 1.3080 
 
 33.43 
 
 90 
 
 1.8115 
 
 73.39 
 
 40 
 
 1.2999 
 
 32.61 
 
 89 » 
 
 1.8043 
 
 72.57 
 
 39 
 
 1.2913 
 
 31.80 
 
 88 
 
 1.7962 
 
 71.75 
 
 38 
 
 1.2826 
 
 30.98 
 
 87 
 
 1.7850 
 
 70.94 
 
 37 
 
 1.2740 
 
 30.17 
 
 86 
 
 1.7774 
 
 70.12 
 
 36 
 
 1.2654 
 
 29.35 
 
 85 
 
 1.7673 
 
 69.31 
 
 35 
 
 1.2572 
 
 28.54 
 
 84 
 
 1.7570 
 
 68.49 
 
 34 
 
 1.2490 
 
 27.72 
 
 83 
 
 1.7465 
 
 67.68 
 
 33 
 
 1.2409 
 
 26.91 
 
 82 
 
 1.7300 
 
 66.86 
 
 32 
 
 1.2334 
 
 26.09 
 
 81 
 
 1.7245 
 
 66.05 
 
 31 
 
 1.2260 
 
 25.28 
 
 80 
 
 1.7120 
 
 65.23 
 
 30 
 
 1.2184 
 
 24.46 
 
 79 
 
 1.6993 
 
 64.42 
 
 29 
 
 1.2108 
 
 23.65 
 
 78 
 
 1.6870 
 
 63.62 
 
 28 
 
 1.2030 
 
 22.83 
 
 77 
 
 1.6750 
 
 62.78 
 
 27 
 
 1.1956 
 
 22.01 
 
 76 
 
 1.6630 
 
 61.97 
 
 26 
 
 1.1876 
 
 21.20 
 
 75 
 
 1.6520 
 
 61.15 
 
 25 
 
 1.1792 
 
 20.38 
 
 74 
 
 1.6415 
 
 60.34 
 
 24 
 
 1.1706 
 
 19.57 
 
 73 
 
 1.6321 
 
 59.52 
 
 23 
 
 1.1626 
 
 18.75 
 
 72 
 
 1.6204 
 
 58.71 
 
 22 
 
 1.1549 
 
 17.94 
 
 71 
 
 1.6090 
 
 57.89 
 
 21 
 
 1.1480 
 
 17.12 
 
 70 
 
 1.5975 
 
 57.08 
 
 20 
 
 1.1410 
 
 16.31 
 
 69 
 
 1.5868 
 
 56.26 
 
 19 
 
 1.1330 
 
 15.49 
 
 68 
 
 1.5760 
 
 55.45 
 
 18 
 
 1.1246 
 
 14.68 
 
 67 
 
 1.5648 
 
 54.63 
 
 17 
 
 1.1165 
 
 13.86 
 
 66 
 
 1.5503 
 
 53.82 
 
 16 
 
 1.1090 
 
 13.05 
 
 65 
 
 1.5390 
 
 53.00 
 
 15 
 
 1.1019 
 
 12.23 
 
 64 
 
 1.5280 
 
 52.18 
 
 14 
 
 1.0953 
 
 11.41 
 
 63 
 
 1.5170 
 
 51.87 
 
 13 
 
 1.0887 
 
 10.60 
 
 62 
 
 1.5066 
 
 50.55 
 
 12 
 
 1.0809 
 
 9.78 
 
 61 
 
 1.4960 
 
 49.74 
 
 11 
 
 1.0743 
 
 8.97 
 
 60 
 
 1.4860 
 
 48.92 
 
 10 
 
 1.0682 
 
 8.15 
 
 59 
 
 1.4760 
 
 48.11 
 
 9 
 
 1.0614 
 
 7.34 
 
 58 
 
 1.4660 
 
 47.29 
 
 8 
 
 1,0544 
 
 6.52 
 
 57 
 
 1.4560 
 
 46.48 
 
 7 
 
 1.0477 
 
 5.71 
 
 56 
 
 1.4460 
 
 45.66 
 
 6 
 
 1.0405 
 
 4.89 
 
 55 
 
 1.4360 
 
 44.85 
 
 5 
 
 1.0336 
 
 4.08 
 
 54 
 
 1.4265 
 
 44.03 
 
 4 
 
 1.0268 
 
 3.26 
 
 53 
 
 1.4170 
 
 43.22 
 
 3 
 
 1.0206 
 
 2.45 
 
 52 
 
 1.4073 
 
 42.40 
 
 2 
 
 1.0140 
 
 1.63 
 
 51 
 
 1.3977 
 
 41.58 
 
 1 
 
 1.0074 
 
 0.82 
 
 The presence of sulphuric acid is detected by adding to any 
 compound in solution a salt of barium, which gives a white 
 precipitate not soluble in nitric acid. Sulphuric acid has a 
 
100 
 
 HYPOSULPHUROUS ACID. 
 
 strong attraction for water, so much so, that if left exposed to 
 the atmosphere, it" will absorb moisture and become dilute. A 
 saucer half-filled with strong sulphuric acid will become full 
 in a few days by exposure to the atmosphere of a dye-house. 
 This shows the evil of leaving the stoppers out of the bottles, 
 or, as is often the case, leaving quantities of this acid in an 
 open jug. Animal and vegetable substances put into sulphuric 
 acid become charred ; the hydrogen and oxygen of these bodies 
 go to form water, which combines with the acid, and the car- 
 bon is left as charcoal ; this is the effect it produces upon the 
 skin. The presence of these matters also tends to weaken the 
 acid, and should therefore be avoided as much as possible. 
 This may be the proper place to refer to a bad practice we 
 have seen in the dye-house. When using vitriol, the jug con- 
 taining it is often placed upon the floor for convenience; and a 
 workman passing that way comes against it with his foot, and 
 not only spills the acid, but occasionally his shoe is filled with 
 it. When this happens, the first impulse, which is often 
 obeyed, is to plunge the foot into water, when, of course, the 
 mixture of vitriol and water in the shoe is brought nearly to 
 the boiling point, as may* be learned from the table above. 
 Severe accidents by this reckless habit are not uncommon. 
 When such an accident does take place, the person ought to 
 take off his shoe and stocking before putting his foot in water ; 
 and if his foot has been previously dry, or merely moist, he 
 will escape unhurt. The hand, if dry, may be kept in strong 
 vitriol for some time, without burning, but very shortly the 
 acid begins to decompose the skin, and then pain is felt. 
 
 Hyposulphurous Acid. — This acid is of singular compo- 
 sition; although it is composed of equal equivalents of sulphur 
 and oxygen, what might be termed SO, yet it is represented 
 double S 2 0 o . This seeming anomaly is got over by supposing 
 it to be a compound of sulphurous acid with sulphur, thus : 
 S0 2 + S. This acid is not prepared directly from its elements, 
 but is formed either in combination as a salt, or by double de- 
 composition. If a current of sulphurous acid gas S0 2 , and 
 sulphureted hydrogen gas SH, are passed through water to- 
 gether, four parts or equivalents of the former, and two parts 
 or equivalents of the latter combine to form three equivalents 
 of hyposulphurous acid, and two of water. The formula may 
 be accordingly this: 4S0 2 and 2SH = 3S 2 0 2 +2HO. The 
 acid, when uncombined, is very unstable ; after exposure for a 
 short time it deposits sulphur, and sulphurous acid remains. 
 
 When a solution of soda or potash is boiled with sulphur, 
 there is formed in the liquid hyposulphate, and sulphuret, of 
 
SULPHURETED HYDROGEN. 
 
 101 
 
 the base, supposing that soda is employed ; then four propor- 
 tions of sulphur, and three of soda, produce 
 
 One hyposulphite of soda NaO S 2 0 2 , and 
 Two sulphuret of sodium 2NaS. 
 
 The hyposulphites are not yet much used in dyeing; but from 
 the property which the alkaline salts of this acid has of dis- 
 solving many metallic oxides, it might undoubtedly be advan- 
 tageously applied for several purposes. 
 
 Hyposulphuric Acid. — This acid is easily formed in com- 
 bination by passing a current of sulphurous acid through water 
 in which is diffused a quantity of black oxide of manganese; 
 two proportions of the acid combine with one proportion of 
 oxygen from the manganese, and form the hyposulphuric acid, 
 which combines with the remaining manganese to form the 
 hyposulphate of manganese :— 
 
 Mn0 2 2S0 2 = MnO S 2 0 5 . 
 
 This acid may be "obtained free from the manganese by pre- 
 cipitating that metal, but cannot be freed from water. Its 
 hydrate is moreover very unstable, but in union with bases it 
 forms salts of great stability. 
 
 Sulphureted Hydrogen. — Sulphur combines with hydro- 
 gen in equal equivalents, and forms a gaseous compound 
 very useful as a test — this is sulphureted hydrogen, or sul- 
 phide of hydrogen, which is not inappropriately termed hydro- 
 sulphuric acid, as the gas has acid properties. This gas is pre- 
 pared by acting upon a metallic sulphuret, with an acid in this 
 manner : A few pieces of protosulphuret of iron are put into 
 a glass or porcelain vessel containing a little water, and a small 
 quantity of sulphuric or hydrochloric acid is added ; a gas of 
 a strong suffocating smell immediately begins to come off, 
 which is sulphureted hydrogen. The reaction which takes 
 place is as follows : — 
 
 Sulphuret of Iron, {| e " ^^^ Sulphide ° f h ^ m - 
 Sulphuric acid, {gj- Sulphate of iron . 
 
 This gas is absorbed by water, and is sometimes used in 
 solution as a test. It is also taken up in great quantity by a 
 solution of ammonia, forming hydrosulphuret of ammonia, 
 also much used as a test. When used for this purpose in 
 the gaseous state, such an apparatus as the accompanying 
 
102 
 
 SULPHUBETED HYDKOGEN. 
 
 will serve. The sulphuret of iron 
 or other sulphuret, is put into the 
 bottle «, containing some water, and 
 the acid is added by the long fun- 
 nel d. The gas escapes by the 
 tube e, /, and passes through the 
 solution to be tested, contained in 
 the glass g. The same apparatus 
 serves for passing the gas through 
 water or liquid ammonia, when it 
 is required to produce a saturated 
 solution. The precipitates formed 
 by passing this gas through solu- 
 tions of various substances are very 
 characteristic. Thus, a solution • 
 containing — 
 
 Antimony produces . . . Orange precipitate. 
 
 Tin and arsenic .... Yellow precipitate. 
 
 Manganese Flesh-red precipitate. 
 
 Zinc White precipitate. 
 
 Lead, copper, iron, &c. . . Black precipitate. 
 
 Sometimes, however, it is necessary to add a little ammonia 
 before these results are obtained. 
 
 Sulphureted hydrogen is evolved from decaying animal and 
 vegetable matters, and from dunghills, common sewers, and 
 putrefying bodies that contain sulphur. It is very deleterious 
 to health, and care should be taken to avoid breathing it. The 
 effect of this gas upon many dyes is so very great that the 
 slightest quantity in the atmosphere is hurtful. It gives to 
 chrome yellows and oranges a smoky appearance, which can- 
 not be removed ; and to spirit reds it gives a rusty brown 
 appearance. Wherever, indeed, there is a metal present in the 
 dye, this gas affects the color. Sulphur does so also; conse- 
 quently the same effects are often produced by burning sul- 
 phury coals in a drying-stove. We have seen a whole stove- 
 charge of goods, yarn, and cloth, spoiled in this way ; the 
 colors appearing as if dried in smoke, and the watchman super- 
 intending the stove, notwithstanding his protestations that 
 there was no smoke, compelled to bear the blame of negligence. 
 
 Sulphur combines with hydrogen in another proportion, and 
 forms a bisulphuret HS 2 , which is an oily liquid of no known 
 importance in any process of the dye-house. 
 
 Fig. 10. 
 
SELENIUM — PHOSPHORUS. 
 
 103 
 
 Selenium (Se 39.5). 
 
 This element very much resembles sulphur in its properties, 
 and in some of its combinations. It is solid, of a dark-brown 
 color and metallic lustre; and is found in nature in combina- 
 tion with some of the metallic sulphurets, as those of copper, 
 silver, lead, &c. It is very rare, and as it has only been obtained 
 in minute quantities, it has not yet been introduced into the 
 arts, or applied to any useful purpose. 
 
 Phosphorus (P 32). 
 
 Phosphorus is a soft, solid substance, of a light amber color, 
 and insoluble in water. It is very abundant in nature in com- 
 bination with other substances, but principally with lime in the 
 bones of animals. It is exceedingly inflammable, oxidates 
 rapidly when exposed to the air, and emits light visible in the 
 dark, from which circumstances it derives its name. It is 
 manufactured from the bones of animals, by various compli- 
 cated methods not very easily imitated on a small scale. 
 
 This element unites with oxygen in various proportions, and 
 most of the compounds formed have acid properties, as : — 
 
 Suboxide of phosphorus P 2 0. 
 
 Hypophosphorous acid PO. 
 
 Phosphorous acid P0 3 . 
 
 Phosphoric acid P0 5 . 
 
 These acids all unite with bases, forming salts which are 
 interesting in their relations to each other, and also to salts of 
 other acids. Phosphoric acid and the phosphates evince 
 peculiar properties in combining with various proportions of 
 water, and producing compounds which differ characteristically 
 from one another. These combinations have been extensively 
 investigated by Professor Graham and other chemists. We 
 are not aware that any of these salts are used in the operations 
 of dyeing, except in so far as they constitute a portion of the 
 salts in dung, and the substance called dung substitute, used in 
 dyeing turkey reds and other madder colors. 
 
 Phosphorus combines also with hydrogen, nitrogen, chlorine, 
 and sulphur, and likewise with many of the metallic elements 
 forming the class of compounds termed phosphurets, or phos- 
 phides. 
 
IODINE. 
 
 Iodine (I 127). 
 
 Iodine is obtained from the ashes of sea-weed. The ashes 
 are put into water, and the soluble portions are withdrawn 
 and boiled down. During the process common salt and other 
 salts are deposited and withdrawn ; and when the liquid is 
 reduced to a very small quantity and attains a dark color, a 
 little sulphuric acid is added; the whole is then allowed to 
 remain at rest for a day or two. The liquor is then mixed up 
 with oxide of manganese, and put into a retort, to which heat 
 is applied. The iodine distils over, and is condensed in re- 
 ceivers fitted to the retort. 
 
 Iodine is a solid substance, of a metallic lustre, and a bluish 
 black color ; it stains the hands yellow if touched, and is 
 volatile at a low heat, rising in vapor of a beautiful violet 
 color. It combines with nearly all the non-metallic elements, 
 and also with the metals; with many of the latter it forms 
 compounds having beautiful colors, suitable in every way as 
 dyes. But from the volatile nature of iodine, the colors pro- 
 duced by it are fugitive, and do not bear exposure. Many 
 attempts have been made to employ the salts of iodine as dye- 
 drugs, and to fix the color, but they have all failed. 
 
 The compounds of iodine with oxygen are the two acids : — 
 
 Iodic acid . . I0 5 | Hyperiodic acid . . I0 7 . 
 
 These acids combine with bases to form salts termed iodates. 
 It forms an acid with hydrogen, namely : — 
 
 Hydriodic acid .... HI. 
 
 The salts which this acid forms are termed hydriodates. 
 
 Iodine combines with starch, and forms a deep blue violet 
 color, which soon passes away. The principal compound with 
 which experiments upon the colors formed by iodine may be 
 carried on, is the iodide of potassium, KI. This is easily pre- 
 pared by boiling iodine in a solution of caustic potash to dry- 
 ness, then fusing the dry mass in an iron vessel or crucible. 
 The result of this is iodide of potassium, which is easily soluble 
 in water. This salt is abundant, and always very pure in com- 
 merce. A little of the solution added to a salt of lead produces 
 a beautiful yellow precipitate, which, when boiled Jin water, 
 and the clear part set aside to cool, gives brilliant golden- 
 colored crystals in scales. The salts of mercury give with 
 iodide of potassium a deep orange-red precipitate. This salt 
 indeed gives precipitates and colors with the salts of nearly all 
 the metals ; and, were it possible to render the colors it affords 
 
BROMINE — FLUORINE. 
 
 105 
 
 permanent, it would no doubt become a most useful drug in 
 the hands of the operative dyer. 
 
 Bromine (Br 80). 
 
 Bromine is another element obtained from the ashes of 
 certain sea-weeds, but not in nearly so great abundance as 
 iodine. It is a liquid at ordinary temperatures ; has a deep 
 red color, and is much heavier than water, in which it is 
 generally kept to prevent it volatilizing, as it does rapidly when 
 exposed to the air. It has a very penetrating odor, and its 
 fumes destroy vegetable coloring matters, leaving merely a 
 yellow tint. 
 
 Bromine is known to combine with oxygen in only one 
 proportion = Br0 5 . This is bromic acid, which combines 
 with bases, forming the salts termed bromates. With hydro- 
 gen it combines and forms hydrobromic acid = HBr, the salts 
 of which are termed hydrobromates. It also unites directly 
 with some of the other elements forming bromides, of which 
 the bromide of potassium is an example. The compounds of 
 bromine with some of the metals might also form a dye, were 
 they procured abundantly ; but the same objection to iodine 
 is also applicable to bromine, it is unstable, and vanishes on 
 exposure. 
 
 Bromine and some of its compounds have been much used 
 in the operations of daguerreotyping. 
 
 Fluorine (M 19). 
 
 This element is only known in combination, and has never 
 been obtained free. By its powerful attraction for every 
 other substance, it fulfils in some degree the old hypothetical 
 notion of a universal solvent. It is however very abundant 
 in nature, combined with calcium as a fluoride, forming the 
 mineral fluor spar. It is not known to combine with oxygen, 
 but it combines very readily with hydrogen, and forms hydro- 
 fluoric acid = HF1. This acid may be evolved from fluor 
 spar by acting upon it with sulphuric acid. It dissolves glass, 
 and all matters containing silica, and therefore cannot be kept 
 in glass, china, or earthenware vessels; and as it dissolves all 
 metals except lead, silver, gold, and platinum, it can only be 
 kept in vessels made of any of these metals, but lead bottles 
 are commonly used. By mixing fluorspar and pieces of glass 
 or fine sand, and acting upon the mixture by strong sulphuric 
 acid, an acid gas is given off; this is fluosilicic acid = SiFl 3 , 
 
106 
 
 SILICI IT M — BORON — CARBON. 
 
 which, together with hydrofluoric acid, combines with water, 
 and is termed hydrofluosilicic acid = 3HF1 + 2SiFl 3 . This 
 solution is occasionally used in the laboratory as a test for 
 potash and soda. 
 
 « 
 
 Silicium (Si 21.3). 
 
 Silicium is a light-brown powder. It is one of the most 
 extensively diffused elements in nature, but it always exists in 
 combination with oxygen, forming silica or silicic acid = Si 0 3 . 
 The substances known as flints, agates, quartz, sand, &c, are 
 nearly pure silica, and every other earthy substance in nature 
 contains more or less silica combined with it. This substance 
 is of essential importance to the potter and glass-maker, but 
 it is of little consideration in dyeing. 
 
 Boron (B 11). 
 
 Boron is a solid, and generally obtained as a greenish brown 
 powder, destitute of metallic lustre. It is not found in nature 
 except in combination with oxygen, with which it forms 
 boracic acid = B0 3 . This acid combines with bases forming 
 borates; but it is found in nature uncombined, especially 
 among the volcanic products of the Lipari Islands.* The prin- 
 cipal sources of the compounds of boron are, however, some 
 springs in India, and the waters of Sasso, which hold in solu- 
 tion a quantity of borate of soda (borax). In some lakes in 
 the neighborhood of volcanoes there are also great quantities 
 of boracic acid. These waters are concentrated by evaporation 
 sufficiently to allow the acid to crystallize, and in this state it 
 is known in commerce as raw borax. Arrived in this country, 
 it is dissolved and saturated with soda to form borate of soda, 
 which is obtained in large crystals ; this is the refined borax 
 of commerce, and the principal compound of boron known in 
 the arts. It is much used in medicine, and as a flux in the 
 operations of metallurgy. 
 
 Carbon (C 6). 
 
 Carbon is very extensively diffused through nature, and the 
 complete description of this element and its compounds would 
 embrace the whole chemistry of organic matter. It is met 
 
 * The greater part of boric acid is actually extracted from the suffioni of 
 Tuscany. 
 
CARBON. 
 
 107 
 
 with also in various forms and combinations in the mineral 
 kingdom. Carbon exists pure in diamond and coal, and forms 
 nearly the whole of plumbago and graphite (popularly Hack- 
 lead)- It may be obtained by submitting either animal or 
 vegetable matter to a high heat in a close vessel ; the oxygen, 
 hydrogen, and nitrogen of these bodies pass off, and the car- 
 bon is left. Charcoal is therefore carbon with a little earthy 
 matter ; and coke, ivory-black and lampblack, are other 
 familiar names for it in an impure state. These substances 
 differ in character from each other in having different propor- 
 tions of earthy ingredients in combination or mixture with the 
 principal element. Carbon is infusible, therefore we only know 
 it in a solid form. It possesses many singular properties con- 
 nected with the principles of dyeing ; some of these we will 
 state here and reserve the applications till we come to consider 
 the methods and theory of dyeing. 
 
 Carbon has the property of absorbing gases within its pores. 
 One cubic inch of the best charcoal made from box-wood has 
 been found to absorb or imbibe the following quantities of the 
 different gases named : — 
 
 Cubic inches. 
 
 90 Ammoniacal gas. 
 
 85 Hydrochloric acid gas. 
 
 65 Sulphurous acid. 
 
 55 Sulphureted hydrogen. 
 
 40 Peroxide of nitrogen. 
 
 35 Carbonic acid. 
 
 9 Oxygen. 
 
 7 Nitrogen. 
 1.7 Hydrogen. 
 
 This curious property is not well understood ; it is generally 
 supposed that it results from the powerful cohesive attraction 
 between the gas and the surface of the charcoal by which the 
 gas is liquefied. Somewhat analogous to this property is its 
 power of absorbing or imbibing coloring matters, and on this 
 account it is extensively used for discoloring sugar ; charcoal 
 has also the property of keeping water sweet for a long time. 
 The various kinds of charcoal possess this discoloring power 
 differently, probably depending on their state of purity. 
 Supposing that the substance to be discolored is sulphate of 
 indigo, the following are the powers of some kinds of charcoal 
 compared with that of charcoal from bones, which we call 1 : — 
 
108 
 
 CARBONIC ACID. 
 
 Lampblack = 4 
 
 Charcoal from starch, ignited with potash . . = 12 
 Lampblack, ignited with carbonate of potash =16 
 Ivory-black, ignited with carbonate of potash = 45 
 Blood charcoal, ignited with carbonate of potash =50 
 
 This property of absorbing colors is also considered an 
 attraction of surface, and it is found in some cases to be suffi- 
 ciently strong to overcome chemical affinity. The same pro- 
 perty of imbibing colors is possessed by other porous matters 
 to some extent, and the porous nature of the fibre of cotton, 
 woollen, and silk, may exercise an influence of a similar kind, 
 a subject which we intend to consider farther on. 
 
 Carbon combines with oxygen in three proportions, form- 
 ing :— 
 
 Carbonic oxide, or oxide of carbon . . . CO. 
 
 Carbonic acid C0 2 . 
 
 Oxalic acid C 2 , 0 3 . 
 
 Carbonic Oxide is obtained by heating together strong vit- 
 riol and crystallized oxalic acid. This operation may be per- 
 formed in a retort or flask, as described for hydrogen (page 50) ; 
 the action taking place is : — 
 
 'Carbon -p-Oxide of carbon. 
 
 V v arbon ^^Z^ Carbonic acid. 
 
 Crystallized , Oxygen , 
 oxalic acid, } Oxygen 
 " Oxygen 
 Water. 
 
 phurkfacii } Sul P huric acid Sulphuric acid. 
 
 The action is simply the sulphuric acid taking the water 
 from the crystallized oxalic acid and setting the elements free. 
 By passing the gases through a solution of caustic potash or 
 lime-water, the carbonic acid is absorbed, and carbonic oxide 
 is obtained pure. It is a colorless gas, inodorous, and burns 
 with a blue flame. It is the presence of this gas which gives 
 the blue flame of a coke fire. The product of its combustion 
 is carbonic acid. 
 
 Carbonic Acid. — When carbon is brought to a red heat, it 
 burns and dissipates; the oxygen combines with the carbon, 
 and produces gaseous carbonic acid. This gas is generally 
 obtained for experiment from its compounds. Thus, when a 
 few pieces of marble or chalk are put into a flask or retort, and 
 some dilute muriatic acid is added, effervescence takes place, 
 and the action is : — 
 
OXALIC ACID. 
 
 109 
 
 Marble.... 
 
 < Calcium . 
 (Oxygen. . 
 J Hydrogen 
 (Chlorine . 
 
 ( Carbonic acid 
 
 Carbonic acid. 
 
 Muriatic 
 acid 
 
 Water. 
 
 Chloride calcium. 
 
 Carbonic acid is absorbed by water, in quantity equal to the 
 volume of the gas ; but the materials from which it is prepared 
 are so cheap, that this absorption does not signify much in an 
 experiment. The gas is colorless, and heavier than atmospheric 
 air, so that it may be poured from one vessel to another, as if 
 it were a liquid. A light is instantly extinguished by immer- 
 sion "in an atmosphere of it, and an animal soon dies if kept in 
 air containing nine per cent, of it. Combined with water, it 
 manifests acid properties, and gives the water an agreeable 
 taste and pungency, as experienced in aerated waters. It com- 
 bines readily with alkaline and earthy bases, producing car- 
 bonates. Its affinity for lime is very great; but it is liberated 
 from all its compounds with effervescence by a stronger acid. 
 When the dry gas is passed over redhot charcoal, it is decom- 
 posed ; the charcoal combines with half its oxygen, and forms 
 oxide of carbon. 
 
 Oxalic Acid has been long known in commerce as salt of 
 sorrel. It was formerly obtained from the oealis acetesella, a 
 plant which contains it as oxalate of lime ; but it is now manu- 
 factured in large quantities from sugar and starch, by acting 
 upon these substances with nitric acid, which oxidates and de- 
 composes them. The action is probably as follows : — 
 
 6 proportions of f 6 Binoxide of nitrogen given off. 
 
 The acid crystallizes with water, which, as has been shown 
 above, is essential to its existence. It combines with bases, 
 and forms salts of great importance in the laboratory. Thus 
 the oxalates of potash and ammonia are excellent tests for lime; 
 and they are also of some importance in the dye house, as are 
 also the oxalates of tin, &c. Oxalic acid is easily distinguished 
 from any of the alkaline and earthy salts, such as the sulphate 
 of magnesia (Epsom salts), for which it has occasionally, 
 through ignorance, been mistaken by its strong acid character. 
 It is easily detected by heating it to redness upon a piece of 
 platinum, when it will all evaporate, and leave no residue, 
 while the magnesian salt does. It sometimes contains nitric 
 acid, peroxide of nitrogen, and Epsom salts ; the first two may 
 
 Sugar, 
 composed of 
 
 nitric acid 
 
110 
 
 CYANOGEN. 
 
 be detected by dissolving a little of the acid, and adding a 
 minute coloring of sulphate of indigo, and then boiling; the 
 presence of these impurities decolors the indigo. The presence 
 of Epsom salts may be detected by chloride of barium, or by 
 evaporation as directed above. There is often about one per 
 cent, of this salt in the commercial oxalic acid. 
 
 This acid has been long used in the dye-house, and acts pow- 
 erfully upon many substances, but it is not now so generally 
 used. A curious salt, of a beautiful color, may be obtained by 
 taking 
 
 One part of bichromate of potash, 
 Two of binoxalate of potash, 
 Two of oxalic acid ; 
 
 and dissolving the whole together in hot water, when carbonic 
 acid is evolved, and a double salt of oxalate of potash and 
 chrome, having a fine purple color, is formed in solution. 
 Crystals of the salt, possessing a very deep blue color, may be 
 obtained by evaporation. 
 
 Cyanogen — Carbon combines with nitrogen, and forms 
 cyanogen, a very important compound, consisting of one equi- 
 valent of nitrogen and two equivalents of carbon = C 2 N. It 
 is a gas, and has the property of combining with other ele- 
 ments as if it were itself an element. It belongs therefore, as 
 was stated at p. 45, to the class of compounds known as salt 
 radicals. It is not obtained by directly bringing nitrogen into 
 contact with carbon, but by the decomposition of animal com- 
 pounds in contact with metallic bases, as we will have occasion 
 to describe farther on. The gas is generally obtained for ex- 
 periment from its salts, by heating cyanide of mercury in a 
 retort. The mercury runs over in a metallic state, and the 
 cyanogen escapes as gas, and may be caught at the pneumatic 
 trough. Cyanogen combines with oxygen, and forms an acid 
 called cyanic acid, and this, combining with bases, forms 
 cyanates. 
 
 Cyanogen combines also with hydrogen, and forms an acid 
 termed hydrocyanic acid, or more commonly prussic acid, 
 which, like hydrochloric acid, does not combine with bases, as 
 C 2 N-f H, and although certain salts are termed prussiates, they 
 are properly cyanides. Some of them are highly important in 
 the arts, and will be noticed in their proper places. 
 
 Cyanogen also combines with the metals in the same man- 
 ner as chlorine and iodine, and forms that class of salts termed 
 cyanides* 
 
 * The distinction between the names ending in ate and ide must here be 
 borne in mind. 
 
MELLON. 
 
 Mellon. — Carbon combines with nitrogen in other propor- 
 tions besides that of cyanogen. There is one expressed by 
 N 4 C 6 , which is a solid substance of a lemon-yellow color, in- 
 soluble in water, but which acts the part of a salt radical, and 
 combines with hydrogen to form an acid which also combines 
 with several of the metallic bases. This salt radical is termed 
 Mellon, and the salts from it are termed mellonides ; but 
 these compounds are not so well known as the cyanides, and 
 they are less useful. 
 
 Carbon combines with hydrogen in various proportions, 
 forming different kinds of gases, such as light carbureted hy- 
 drogen = CH 2 ; olefiant gas = C 4 H 4 ; common coal gas, and 
 some other hydrocarbons consist of those gases as constitu- 
 ents. Carbon also combines with sulphur, and forms with it a 
 colorless, volatile, and inflammable liquid, possessing a most 
 putrid smell : this is sulphuret of carbon. In organic bodies, 
 carbon is combined with oxygen, hydrogen, and nitrogen, in 
 an endless variety of proportions. Some of these compounds 
 will be brought under notice when treating of the organic sub- 
 stances which fall within the scope of our subject. 
 
112 
 
 METALLIC SUBSTANCES. 
 
 General Properties of Metals. 
 
 We now proceed to consider that division of the elements 
 commonly known as metals. To define the peculiar properties 
 of a metal is somewhat difficult, for whichever property we 
 select, it is either absent in some metal, or it is possessed by 
 some non-metallic element. A few of the more prominent 
 physical properties may, however, be named. 
 
 1st. They all possess a peculiar lustre. 2d. They all reflect 
 light, which is the cause of that lustre. 3d. They are all 
 fusible by heat, and while in fusion retain their lustre. 4th. 
 They are all conductors of light and heat. 5th. They have 
 all to a certain degree the property of extension ; they are 
 malleable under the hammer; and laminahle under the roller; 
 and being capable of extension by drawing into wire, they are 
 termed ductile. 
 
 There are also chemical distinctions which are much more 
 universal. They are all basic, that is to say, capable of com- 
 bining with oxygen, and forming oxides; and with acids they 
 form a series of compounds termed salts, of which the metal 
 is termed the base. It is on account of the possession of these 
 general properties that hydrogen is regarded as a metal in a 
 gaseous state ; it is pre eminently basic. 
 
 When metals combine with one another, the compound is 
 termed an alloy. Brass is a chemical mixture of copper and 
 zinc; and German silver is a like mixture of copper, zinc, and 
 nickel ; both brass and German silver are therefore alloys. 
 Alloys retain most of the physical properties of the metals of 
 which they consist. A great many of the recently discovered 
 metals are very rare, and have only been found in certain 
 localities, and in minute quantities. The alkalies and earths 
 were long looked upon as elements ; they had never, indeed, 
 been decomposed till 1807. What was until that time known 
 as the element — 
 
 Potash, we now know to be the oxide of the metal Potassium. 
 
 Soda Sodium. 
 
 Lithia Lithium. 
 
 Lime Calcium. 
 
 Barytes or Baryta Barium. 
 
 Magnesia Magnesium. 
 
 Alumina Aluminum. 
 
POTASH. 
 
 113 
 
 Potassium (K 39.2). 
 
 Sir H. Davy decomposed potash by a powerful electric 
 current, and demonstrated it to be the oxide of a peculiar 
 metal which he termed potassium. This metal may be ob- 
 tained easily by roasting a quantity of bitartrate of potash 
 (cream of tartar) in a covered crucible : the immediate product 
 is what is termed black flux ; then mixing this matter with a 
 quantity of finely-ground charcoal, and putting the whole into 
 a wrought-iron bottle, and distilling it at a high heat, the metal 
 comes over, and is caught in a vessel containing naphtha, a 
 fluid that contains no oxygen. Only such a fluid can be used 
 for this purpose, as the attraction of potassium for oxygen is 
 so great, that it decomposes all substances which contain that 
 element. 
 
 Potassium is a white metal, with a lustre somewhat like 
 silver; at ordinary temperature it is soft, and may be flattened 
 between the fingers, but at 32° it is hard and brittle. It melts 
 at 136°. When exposed to the air, it becomes covered imme- 
 diately with a white crust of oxide. It is lighter than water, 
 and when thrown upon that fluid it swims, and instantly 
 bursts into flame, combining with the oxygen of the water so 
 rapidly as to produce heat sufficient to kindle the hydrogen as 
 it makes its escape. The metal not only fuses, but a small 
 portion of it goes off as vapor, and burning with the hydrogen 
 produces a beautiful red colored flame. In this experiment 
 potash is formed in the water. Pure potash is the oxide of 
 the metal potassium, but it is not prepared from the metal for 
 manufacturing purposes. 
 
 Potash. — Sometimes termed the vegetable alkali, takes its 
 name from being prepared for commercial purposes in iron 
 pots. When a piece of wood, or other vegetable substance, is 
 slowly burned until all inflammable matters are consumed, 
 there is left a white substance called ash. This ash consists 
 of the mineral ingredients of the vegetables, along with potash, 
 lime, and other earthy ingredients. The potash and other 
 soluble ingredients are extracted by treating the ash with 
 water. 
 
 The average quantity of ash pbtained from wood is about 
 one per cent. In America, where wood is an incumbrance, it 
 is felled, piled up in masses, and burned for the manufacture 
 of potash. The ashes of the wood are collected and put into 
 cisterns provided with false bottoms, and run-off plugs under- 
 neath. A quantity of water is thrown upon the ashes in a 
 cistern, and after stirring and settling a few hours, all the 
 8 
 
114 
 
 POTASH. 
 
 soluble matters are dissolved, and the liquor is drawn off, 
 evaporated to dryness, and the residue afterwards fused at a 
 red heat into compact masses, and in this state constitutes the 
 commercial black ash. As other matters besides the potash 
 are soluble in water, the black ash thus prepared contains 
 these substances as impurities. These are mainly sulphites, 
 sulphurets, and chlorides of potash, along with some earthy 
 matters. 
 
 Pearlash is prepared by calcining the black ash in a rever- 
 beratory furnace until all the carbonaceous matters and the 
 sulphur are driven off. The remaining mass is then dissolved 
 in water, and the solution evaporated to dryness in large iron 
 pans. Towards the conclusion of the process, the mass is 
 stirred to give it a lumpy granulation. This ash contains 
 much less extraneous matter than black ash, and is conse- 
 quently weaker as an alkali. It is more fully carbonated. 
 Dr. Ure states [Dictionary of Arts, &c.) that he found the 
 best pink-colored Canadian potash to contain 60 per cent, of 
 real potash, while the best pearlash contained only 50 per 
 cent. These are the two states in which potash is introduced 
 into the dye-house. The methods'for testing the quantity of 
 real alkali they contain will be given when we come to speak 
 of soda. 
 
 The principal use of potash is to destroy or take off any 
 grease or oil which may exist in or upon the fibre to be dyed, 
 and it does this by combining with these substances and form- 
 ing soap which, being soluble in water, is easily removed. 
 Dyers are often in the habit, when about to steep or boil their 
 goods, of simply adding to their solution or boiler, some pearl- 
 ash or potash, but as the alkali is in union with an acid (car- 
 bonic acid) forming a carbonate, its power of combining with 
 oil or grease is to a great extent neutralized. The white ob- 
 tained upon the fabric may be good enough, and as was before 
 remarked when speaking of chlorine, a good white can be got 
 without potash ; but it is not so permanent. If grease or oil 
 be present it is not removed, but only concealed, and the 
 dyer is often annoyed by large resist spots which he cannot 
 account for, and which are not so easily removed after the 
 goods are boiled as before. The alkali, whether pearl or 
 potash, before being used ought to be made caustic, that is, 
 deprived of its carbonic acid, and converted into oxide of 
 potassium. This is done by boiling the carbonated alkali with 
 newly slaked lime ; the lime combines with the carbonic acid 
 of the alkali, and falls to the bottom, while the caustic alkali 
 remains in solution. Without detailing the various methods 
 practised, some of which are not good, we shall rather give 
 
POTASH. 
 
 115 
 
 what we consider the best. The carbonate of potash ought to 
 be dissolved in not less water than six times its weight; it is 
 better, however, to use ten times its weight, as if a less quan- 
 tity of water be used, the potash is not deprived of all its car- 
 bonic acid. The reason assigned for this singular phenomenon 
 is, that both caustic potash and its carbonate have a strong 
 affinity for water, and when less than six times its weight is 
 used, there is sufficient water to supply the carbonate, but not 
 the caustic alkali, and hence the carbonate is not converted 
 into the caustic state. The exact quantity of lime is not ma- 
 terial, provided there be enough. The lime ought to be added 
 when the alkali is boiling, and from time to time, until, a little 
 of the solution being taken out, it does not effervesce by the 
 addition of a little dilute sulphuric acid. If strong acid is 
 used, care must be taken before adding it that the solution be 
 cold, for if not, it will spirt, and may injure the manipulator. 
 The best way is to take a little of the alkali and dilute it with 
 cold water, and then add the acid. When there is no effer- 
 vescence, the alkali is caustic. The boiling is then stopped, 
 and when the lime settles the clear is taken off and kept in an 
 iron vessel covered closely, as the potash readily takes up car- 
 bonic acid from the air. For bleaching, and other cleansing 
 operations, and also for many purposes in the dye-house, the 
 supply should be taken from this stock vessel. It will be 
 necessary, however, that the operator know the exact strength 
 of the solution, in order that he may know the proper quanti- 
 ties of it he ought to use for particular purposes. On this 
 point a pretty correct approximation is obtained by knowing 
 the percentage of pearl or potash used in making the solution, 
 and then calculating the quantity to each gallon ; but greater 
 exactness is attained by using the following table (drawn up 
 by Dr. Dalton), in which the specific gravity is supposed to be 
 known, and hence the quantity present of the alkali in solu- 
 tion : — 
 
116 
 
 POTASH. 
 
 Potash per cent, in 
 solution. 
 
 Specific gravity of 
 solution. 
 
 Specific gravity by 
 xwaaaen s. 
 
 Boiling point of 
 solution. 
 
 ' 72.4 
 
 2.000 
 
 200° 
 
 600° 
 
 63.6 
 
 1.880 
 
 176 
 
 420 
 
 56.8 
 
 1.780 
 
 156 
 
 360 
 
 51.2 
 
 1680 
 
 136 
 
 320 
 
 46.7 
 
 1.600 
 
 120 
 
 290 
 
 42.9 
 
 1.520 
 
 105 
 
 276 
 
 39.6 
 
 1-470 
 
 94 
 
 265 
 
 36.8 
 
 1.440 
 
 88 
 
 255 
 
 34.4 
 
 1.420 
 
 84 
 
 246 
 
 32.4 
 
 1.390 
 
 78 
 
 240 
 
 29.4 
 
 1.360 
 
 72 
 
 234 
 
 26.3 
 
 1.330 
 
 66 
 
 229 
 
 23.4 
 
 1.280 
 
 56 
 
 224 
 
 19.5 
 
 1.230 
 
 46 
 
 220 
 
 16.2 
 
 1.190 
 
 38 
 
 218 
 
 13. 
 
 1.150 
 
 30 
 
 215 
 
 9.5 
 
 1.110 
 
 20 
 
 214 
 
 4.7 
 
 1.060 
 
 12 
 
 213 
 
 / 
 
 In the first column of this table the percentage of alkali is 
 given by weight. Thus a gallon of water is 10 lbs. weight, 
 therefore a gallon of the caustic lye solution will have one- 
 tenth part of the potash indicated by the table according to 
 the specific gravity. Say the solution stands 30° by Twad- 
 dell — the percentage of this is 13, and this divided by 10 
 gives 1.3 lb. = 1 lb. 5 oz. nearly of caustic potash to a gallon 
 of the lye. The stock lye should not be made stronger than this. 
 
 In the last column the boiling points of the solution at dif- 
 ferent strengths are entered. These numbers are important, 
 and explain to some extent why boiling by steam is not so 
 effective as by fire ; for the steam heat as was stated at page 
 22, is not higher than 210°, whereas the lowest temperature 
 noted in the table is 213°. 
 
 Potash, as used in the dye-house, is never chemically pure. 
 Even when used as caustic, it generally contains lime and soda, 
 and often their sulphurets. Lime may be detected by adding 
 a little clear solution of carbonate of potash to a clear solution 
 of the caustic potash, when its presence will be known by the 
 milkiness produced. It is not, however, detrimental to the dyer 
 in the operations in which potash is commonly used. Sulphu- 
 rets may be detected by adding to a dilute solution of the 
 
SALTS OF POTASH. 
 
 117 
 
 potash some acetate of lead ; if a sulphuret is present, there 
 will be a blackish precipitate. Sulphurets are destructive to 
 gold ornaments on muslin and other cloths, for the metal is 
 rarely pure ; commonly it is an alloy of gold with copper, &c, 
 and sometimes the inferior metal is merely gilt. The sulphuret 
 acts upon all the inferior metals by contact, and at least black- 
 ens them. Potash containing sulphurets should therefore be 
 avoided for goods having such ornaments. 
 
 Caustic potash is evaporated to dryness, fused and poured 
 into moulds to form it into small cylinders; in this state it is 
 sold by druggists under the name of stick-potash. 
 
 Potash has a strong affinity for water, and deliquesces rapidly 
 when exposed to the air; this property is also possessed by 
 the carbonates. 
 
 The following table gives the average quantity of pure alkali, 
 &c, in the different sorts of commercial potash: — 
 
 Name of place from 
 which it is procured. 
 
 Real 
 potash. 
 
 Sulphate 
 
 of 
 potash. 
 
 Muriate 
 
 of 
 potash. 
 
 Carbonic 
 acid and 
 water. 
 
 Insoluble 
 ingredi- 
 ents. 
 
 Total. 
 
 Potash of Kussia, 
 
 772 
 
 65 
 
 5 
 
 254 
 
 56 
 
 1152 
 
 — America, 
 
 857 
 
 154 
 
 20 
 
 119 
 
 2 
 
 1152 
 
 American pearl, 
 
 754 
 
 80 
 
 4 
 
 308 
 
 6 
 
 1152 
 
 Potash of Treves, 
 
 720 
 
 165 
 
 44 
 
 199 
 
 24 
 
 1152 
 
 — Dantzic, 
 
 603 
 
 152 
 
 14 
 
 304 
 
 79 
 
 1152 
 
 — Vosges, 
 
 444 • 
 
 148 
 
 510 
 
 304 
 
 34 
 
 1440 
 
 Potassium combines with chlorine, and forms chloride of 
 potassium — more commonly termed muriate of potash ; which 
 may be prepared by adding hydrochloric acid to caustic potash, 
 or its carbonate. It combines also with iodine, and forms 
 iodide of potassium (page 104):- with bron^ide it forms bro- 
 mide of potassium ; and with sulphur it forms the sulphuret, or 
 sulphide of potassium. We have already noticed most of these 
 salts. 
 
 Sulphate of Potash. — When sulphuric acid is added to 
 potash, it forms a salt which has neither acid nor alkaline pro- 
 perties, and which is easily crystalized. This neutral salt is 
 produced abundantly in the manufacture of nitric acid from 
 nitre. It is not deliquescent*, and requires 15 times its own 
 weight of water to dissolve it. 
 
 Bisulphate of Potash. — This salt is also obtained like the 
 sulphate in the process of making nitric acid from nitre; but 
 it may be prepared by adding to the sulphate half its weight of 
 sulphuric acid, and bringing the mixture up to a red heat in a 
 
118 
 
 SALTS OF POTASH. 
 
 porcelain or platinum vessel. This salt has strong acid reac- 
 tions, is very soluble in water, melts easily with heat, and is 
 exceedingly useful for dissolving metals, many of which may 
 be dissolved by it easily, although of very difficult solution in 
 the pure acid. 
 
 Sulphite of Potash is prepared by passing a current of 
 sulphurous acid gas through a solution of carbonate of potash 
 till saturated. It crystallizes, and should be kept close, as it 
 rapidly passes to the state of sulphate by exposure to the air. 
 
 Nitrate of Potash may be prepared by saturating potash 
 with nitric acid ; but it is obtained abundantly in native beds 
 (page 62). It is prepared artificially in Germany and France, 
 by forming large beds of animal and vegetable refuse, in which 
 decomposition is effected by putrefaction. Potash is present 
 in the organic matters, and these also yield nitrogen and oxygen 
 to form nitric acid; and by combination the nitrate of potash 
 is formed. The chief uses of nitrate of potash are in the man- 
 ufacture of gunpowder and nitric acid. 
 
 Chlorate of Potash is prepared by passing chlorine gas 
 through carbonate of potash. When the solution is saturated, 
 crystals of this salt are formed (page 70). This salt, as already 
 stated, is advantageously used in several operations in the dye- 
 house, in which oxidation is required ; also with decoctions of 
 some of the woods. When mixed with substances containing 
 carbon, it gives them great combustibility. Thus, if a drop 
 of sulphuric acid is added to a mixture of chlorate of potash 
 and sugar, combustion instantly commences, and the mixture 
 burns with great rapidity. 
 
 Phosphate of Potash. — This salt is obtained by adding 
 carbonate of potash to a hot solution of phosphoric acid, until 
 the solution ceases to redden blue litmus paper. By careful 
 evaporation the salt may be crystallized. 
 
 If the carbonate of potash be added to the phosphoric acid 
 while cold, in sufficient quantity to saturate it, the solution, by 
 evaporation, gives crystals of a salt having two proportions of 
 acid — a biphosphate of potash. 
 
 Oxalate of Potash. — This salt is obtained by saturating 
 carbonate of potash with oxalic acid, and crystallizing. In this 
 state it contains one proportion of water. 
 
 The Binoxalate is obtained from wood-sorrel, in which it 
 exists ready formed. It is obtained by reducing the expressed 
 juice of the sorrel to the consistence of a syrup, and setting it 
 aside to crystallize. It is sold as salt of sorrel and essential salt 
 of lemons. The taste of the salt is acid; it is employed for re- 
 moving ink stains from goods, and recently formed iron moulds. 
 Its crystals are composed of 2 acid, 1 potash, and 2 water. 
 
FERROCYANIDE OF POTASSIUM. 
 
 119 
 
 Ferrocyanide of Potassium. — This salt is known as yellow 
 prussiate of potash. We have already referred to the corn- 
 pound salt radical termed cyanogen, and stated that it com- 
 bines with other bodies, and forms salts resembling the chlorides ; 
 but it is occasionally found that two such salts group together 
 and form a distinct compound. Thus, one proportion of the 
 protocyanide of iron == Fe Cy, combines with two proportions 
 of cyanide of potassium, =2 Cy K, and forms the ferrocyanide 
 of potassium. These two proportions of potassium may be re- 
 placed by another metal, but the iron and the three equivalents 
 of cyanogen maintain themselves together. It has, therefore, 
 been inferred that Fe Cy 3 is a distinct salt radical, which may 
 be termed ferro-prussic acid ; a theoretical deduction very in- 
 teresting to study, and which will be more fully developed as 
 we proceed. The salts formed by this acid are distinguished 
 by the prefix ferro. 
 
 The ferrocyanide of potassium, or prussiate of potash, is 
 prepared on a large scale by calcining together dried blood, 
 hoofs, horns, hides, old woollen rags, or similar materials, with 
 carbonate of potash, in an iron vessel ; commonly those sub- 
 stances are partly carbonized or burnt in large cast-iron cylin- 
 ders previously to being mixed with the potash. If the animal 
 matters are used without being subjected to this preliminary 
 process, they are mixed in the ratio of about 8 to 1 of pearlash ; 
 but if burned previously, one and a half of the charcoal is 
 mixed with one of pearlash. When the animal matters are 
 used without being charred, the calcining pot is left open to 
 allow the materials to be stirred and the noxious vapors to es- 
 cape ; after which the vessel is closed, and the heat is increased. 
 This is continued for some time, and, at intervals of half an 
 hour, the mouth of the vessel is uncovered for the purpose of 
 stirring the matter within. This process is continued until the 
 flame ceases to rise from the surface and the materials are re- 
 duced to a red semifluid mass, which generally takes place in 
 about eight hours after the pot is closed. From this descrip- 
 tion, the nature of the action is easily understood. The animal 
 matters which contain nitrogen and carbon abundantly are 
 decomposed by the heat ; but, on account of the presence of 
 the iron and potash, definite portions of the elements combine 
 and form cyanogen, which is simultaneously taken up by the 
 potassium and iron, and we have two proportions of cyanide 
 of potassium, with one proportion of cyanide of iron. The 
 molten mass is scooped out with iron ladles, and allowed to 
 cool. When the mass has cooled, it is dissolved in cold water, 
 and the solution is filtered through cloth. Lest any cyanide 
 of potassium should remain which had not received the pro- 
 
120 
 
 FERROCYANIDE OF POTASSIUM. 
 
 portion of iron, sulphate of iron (copperas) is added by degrees 
 to the solution, so long as the Prussian blue which is at first 
 formed on adding the iron salt is redissolved. The whole is 
 then evaporated to a proper consistency ; after which, pieces 
 of coarse cord are suspended throughout the liquid, upon which 
 crystals of ferro-prussiate are formed in regular bunches, of a 
 beautiful light citron-yellow. 
 
 Ferrocyanide of potassium crystallizes with three proportions 
 of water, which it loses at 212°. It dissolves in 4 parts of 
 cold and 2 parts of boiling water. From this salt all other 
 ferrocyanides are derived as precipitates ; those of the metals are 
 formed by adding a salt of the metal to a solution of the prus- 
 siate. The following are the appearances of a few of those 
 precipitates, corresponding to the metals employed: — 
 
 Protoxide of Manganese . White, turning to a deep red. 
 Peroxide of Manganese . Greenish-gray. 
 Oxide of Lead .... White, with a yellowish hue. 
 Peroxide of Iron . . . Deep blue. 
 
 Protoxide of Iron . . . White, turning blue by exposure. 
 Oxide of Copper .... Brown. 
 
 Each of these precipitates is a ferrocyanide of the metal 
 used, which has taken the place of the potassium ; they are all 
 insoluble in water, and where a color can be obtained by them, 
 they are suitable for a dye, although the colors dyed by the 
 yellow prussiate are fugitive. Every alkaline substance, such 
 as soap, destroys them, and they are easily affected by that 
 universal creator and destroyer of colors, the sun. 
 
 The principal use of the ferrocyanide salt in the dye-house 
 is for dyeing Prussian blue. To dye this color, the goods are 
 impregnated with a persalt of iron, and then passed through 
 a solution of yellow prussiate of potash; but this mode is ob- 
 jectionable for light shades and light goods, as it causes much 
 loss of the Prussian salt. The general method of dyeing light 
 Prussian blues upon cloths is, to put a little nitrate of iron into 
 a vessel full of water ; the cloth is wrought in this for about 
 ten or fifteen minutes, and then washed through two or three 
 tubs full of clean water, to take off all the superfluous acid 
 and iron. Whether the cause of the reception of the dye be 
 an attraction of the material of the cloth for the iron, or the 
 simple power of absorption of the fibres, we shall not stay to 
 examine here; but although the nitrate of iron is an exceed- 
 ingly soluble salt, a portion of the peroxide of iron remains 
 
 — Zinc 
 Protoxide of Tin 
 Peroxide of Tin 
 
 . White. 
 . White. 
 . Yellow. 
 
PRUSSIAN BLUE. 
 
 121 
 
 fixed in the fibres, having abandoned its acid, and this no wash- 
 ing will remove. The cloth, being well washed from the acid, 
 is put into the prussiate. A small quantity of acid must be 
 added to the ferrocyanide of potassium solution, to take up the 
 potassium, and to set the ferrocyanogen at liberty, to unite with 
 the iron upon the cloth ; this forms ferrocyanide of iron, or 
 Prussian blue, and constitutes the dye. Considerable care 
 ought to be taken in adding acid to the prussiate, otherwise 
 the color is liable to change, becoming gray or reddish when 
 dried. 
 
 The following mode of adding sulphuric acid to the prus- 
 siate/ when a considerable quantity of goods are to be dyed at 
 once, is commonly practised. What is considered the proper 
 quantity of yellow prussiate of potash is dissolved in just as 
 much boiling water as is necessary for solution. To this solu- 
 tion a quantity of sulphuric acid is added, sufficient to make 
 it strongly acid ; and the mixture thus prepared is added to the 
 prussiate tub as required. This method of adding the sulphuric 
 acid is exceedingly objectionable, as it causes the evolution of 
 prussic acid, which may be detected by the pungent smell it 
 excites; and in proportion to the escape of that gas, there is a 
 loss of the dyeing power of the prussiate. If three parts of 
 acid be added to seven of yellow prussiate, the loss would 
 amount to one-half, and the remaining half would be so changed 
 in its properties as to produce only a bad blue. Thus the 
 dyer must use an additional quantity of prussiate, and after 
 all he produces but an indifferent color. 
 
 The proper method of using the acid is to dissolve the prus- 
 siate in hot water, and to add the necessary quantity of this 
 solution to the water-tub in which the goods are to be dyed. 
 Previously to putting in the cloth, a few drops of sulphuric 
 acid are added, just sufficient to be perceptible to the taste; or, 
 what is a much better test, sufficient to redden blue litmus paper. 
 The goods being wrought for some time in this mixture, they 
 are washed in clean water, having a small quantity of alum in 
 solution. For light shades of sky-blue, they should not be 
 dried from the alum solution, as there is a great tendency to 
 assume a lavender hue. A better plan is to employ two tubs 
 of water, the one being touched with alum, and the other pure, 
 for washing from it. Cloths dyed by the prussiate should be 
 exposed to a very dry atmosphere when hung up to be dried. 
 
 Deep blue is dyed by passing the goods through strong ni- 
 trate of iron, then through potash lye, which fixes the oxide of 
 iron upon the cloth, and then through the prussiate. 
 
 Eoyal blue is dyed by adding protochloride of tin (salts of 
 tin) to the nitrate of iron ; entering the goods immediately, and 
 
122 
 
 FERRICYANIDE OF POTASSIUM. 
 
 passing them from the iron through the prussiate without wash- 
 ing. This method gives a rich deep blue, and is now much 
 practised. Some of the peculiarities of the process will here- 
 after be described ; meantime, it will be sufficient to observe, 
 that a peculiar purple bloom is given, by using hydrochloric 
 acid in the prussiate solution instead of sulphuric acid. 
 
 Ferricyanide of Potassium. — This is the red prussiate of 
 potash. If a current of chlorine gas be passed through a strong 
 solution of yellow prussiate of potash, till the solution changes 
 to a reddish color, and when a drop of it added to nitrate of 
 iron gives no precipitate, there is formed chloride of potassium, 
 and a salt differing materially from yellow prussiate. The solu- 
 tion being evaporated, this salt is obtained in beautiful ruby- 
 red crystals, termed, from their color, red prussiate of potash. 
 They are anhydrous, soluble in 4 parts of cold and a less 
 quantity of hot water. The red prussiate is well adapted for 
 many operations in dyeing, but it is too expensive for general 
 use. It yields the following colors with the salts of the differ- 
 ent metals undernamed : — 
 
 Bismuth Pale yellow. 
 
 Cadmium Yellow. 
 
 Cobalt Dark-brown red. 
 
 Copper Yellowish-green. 
 
 Protosalts of iron . . Deep blue. 
 
 Persalts of iron . . . No precipitate. 
 
 Manganese Brown. 
 
 Mercury Red -brown. 
 
 Nickel Yellowish-brown. 
 
 Tin White. 
 
 Zinc Orange-yellow. 
 
 It will be observed from this table, that the salts of iron, 
 which yield a blue with yellow prussiate of potash, give no 
 color with the red prussiate; and the protosalts of iron, which 
 give only a gray with yellow prussiate, yield a deep blue with 
 red prussiate. 
 
 The true constitution of this salt, or rather the arrangement 
 in which these elements unite, is still subject of hypothesis. 
 We have seen, in regard to the ferrocyanide, that the iron 
 exists as a protocyanide, with two cyanides of another metal ; 
 but in the ferricyanide we have iron as a percyanide, with 
 cyanides of other metals. Thus: — 
 
 Ferrocyanide . . Fe Cy + 2 Cy K = Protocyanide. 
 Ferricyanide . . Fe 2 Cy 3 + 3 Cy K == Percyanide. 
 
 Those who suppose that the compound Fe Cy 3 of the yellow 
 prussiate forms the salt radical of all the ferrocyanides, suppose 
 
SODIUM. 
 
 123 
 
 also that the red prussiate has Fe 2 Cy 6 , consisting of the same 
 number of elements combined together in double proportions, 
 corresponding to the pro and per oxides of iron. But whatever 
 may be the true relation in which the elements are united, the 
 two salts are distinct in their reactions, and we would suggest 
 to the dyer to give particular attention to the difference of the 
 salts, with reference to salts of iron, as they are important, and 
 will be referred to hereafter. 
 
 Cyanide of Potassium. — If yellow prussiate be dried at a 
 heat of about 220° to 300°, and 8 parts of this dried salt be 
 mixed with 3 parts of dry carbonate of potash and the mix- 
 ture put into a crucible, and fused until effervescence ceases, 
 then removed from the fire, and allowed to settle for a few 
 minutes ; by pouring off the clear into an iron vessel, it solidi- 
 fies into a white crystalline mass, which is cyanide of potas- 
 sium = Cy K. This salt has a strong alkaline reaction, and 
 is peculiar for its power of dissolving metals and giving pre- 
 cipitates which might be advantageously applied to some of the 
 operations of dyeing. 
 
 Cyanate of Potash. — This salt is prepared in the same 
 way as the last, but with the addition of some oxide of man- 
 ganese, or other oxide, which converts the cyanogen into 
 cyanic acid, and forms cyanate of potash = Cy O, KO. The 
 cyanates of the alkalies are all soluble in water, and in this 
 they differ from the cyanates of the other metals. 
 
 Sodium (Na 23). 
 
 Soda was not distinguished from potash till near the middle 
 of the eighteenth century, when their distinctive characters 
 were recognized. The potash was termed the vegetable, and 
 the soda the mineral alkali. In 1807, Sir H. Davy demon- 
 strated that soda, like potash, is the oxide of a metal which 
 he named sodium. It is a white metal, having much the 
 appearance of silver, but is sufficiently soft to yield to the 
 pressure of the fingers, and to be cut by the nail. It oxidates 
 spontaneously in the air, but not so rapidly as potassium. 
 When a small piece is thrown upon water, it floats ; the heat, 
 generated by combining with the oxygen of the water, melts 
 it, and it forms a silvery globe, which gyrates rapidly on the 
 surface of the water; but it does not inflame the hydrogen 
 unless it be kept stationary, and then an explosion takes place. 
 If, however, the temperature of the water is as high as 110° 
 Fah., the hydrogen burns as it is evolved, with a bright flame. 
 In these experiments, oxide of sodium is formed, and dissolved 
 
124 
 
 SODA. 
 
 in the water, which thus becomes a solution of caustic soda. 
 Sodium is a very abundant element in nature, but is always 
 found in combination, e. g. as nitrate of soda and chloride of 
 sodium (common salt). This last is the great source of soda 
 for manufacturing purposes; and since the process of making 
 soda from it was discovered, this alkali, owing to its cheapness, 
 has been used instead of potash in almost all the processes of 
 the arts that admit of the substitution. 
 
 Soda, as sold to dyers and bleachers, is in the state of a dry 
 white powder, or granular substance, termed soda-ash, which is 
 an impure carbonate prepared as follows: A quantity of about 
 600 lbs. of common salt is put upon the bottom of a reverbe- 
 ratory furnace, previously heated ; upon this is let down, from 
 an apparatus on the roof of the furnace, a quantity of sulphuric 
 acid, of the specific gravity 1.600; and the salt is decomposed. 
 The result is as follows: — 
 
 The hydrochloric acid passes off with the steam occasioned by 
 the dilute sulphuric acid. This operation, during which the 
 materials require to be stirred occasionally, lasts about four 
 hours; the charge is then withdrawn from the furnace. The 
 sulphate of soda thus prepared is reduced to powder, and 
 mixed with an equal weight of ground chalk, and half its 
 weight of coal, well ground and sifted. This mixture is intro- 
 duced into a very hot reverberatory furnace, about two hun- 
 dred weight at a time, and is frequently stirred until it is 
 uniformly heated. In about an hour it fuses; it is then well 
 stirred for about five minutes, and drawn out with a rake into 
 a cast-iron trough, in which it is allowed to cool and solidify. 
 This is called ball-soda, or British barilla, and contains about 
 22 per cent, of alkali. To separate the salts from insoluble 
 matter, the cake of ball-soda, when cold, is broken up, put 
 into vats, and covered by tepid water. In six hours, the so- 
 lution is drawn off' from below, and the washing repeated about 
 eight times, to extract all the soluble matter. These liquors 
 being mixed together, are boiled down to dryness, and afford 
 a salt which is principally carbonate of soda, with a little caustic 
 soda and sulphuret of sodium. For the purpose of getting rid 
 of the sulphur, the salt is now mixed with one-fourth of its 
 bulk of saw-dust, and exposed to a low red heat in another re- 
 verberatory furnace for about four hours, which converts the 
 caustic soda into carbonate, when the sulphur is carried off. 
 
 Common salt.. 
 Sulphuric acid 
 
 Hydrochloric acid. 
 
 Sulphate of soda. 
 
SODA-ASH. 
 
 125 
 
 This product, if the process is well conducted, contains about 
 50 per cent, of alkali, and forms the soda-ash of the best quality. 
 When it is to be converted into crystallized carbonate of soda, 
 it is dissolved in water, allowed to settle, and the clear liquid 
 boiled down until a pellicle appears on its surface. The solu- 
 tion is then run into shallow boxes of cast-iron to crystallize 
 in a cool place, and, after standing for a week, the mother 
 liquor is drawn off, and the crystals drained and broken up for 
 the market. This mother liquor is evaporated to dryness, and 
 yields a very impure soda-ash, containing about 30 per cent, 
 of alkali, which is often employed for making soap. 
 
 The common crystallized carbonate of soda of the shops is 
 very pure, but is crystallized with 10 equivalents of water. 
 When exposed to the air, these crystals lose a portion of their 
 water, and assume a chalky, white appearance; if they are sub- 
 jected to heat, they melt in their water of crystallization. We 
 have known these crystals used for the operations of bleaching 
 merely dissolved ; but they are neither good nor profitable, 
 used in this way. 
 
 They contain in 100 parts by weight, 
 
 Caustic soda 21.81 
 
 Carbonic acid 15.43 
 
 Water 62.76 
 
 100.00 
 
 Thus fully more than three-fifths of their weight is water. 
 
 The dry carbonate of soda of the shops, so much used for 
 domestic purposes, is the same as the crystallized soda de- 
 prived of its water of crystallization. 
 
 Soda-Ash. — Owing to various circumstances attending the 
 manufacture of this salt, its percentage is very uncertain, 
 varying from 40 to 50 per cent., and it is, therefore, generally 
 priced according to its percentage. The percentage may be 
 determined by some such means as we have described for 
 bleaching powder, that is, by having an acid exactly of the 
 strength at which 100 measures of it will saturate 100 grains of 
 caustic soda. To form the test acid, according to Professor Gra- 
 ham's directions, 4 ounces avoirdupois of oil of vitriol are 
 diluted with 20 ounces of water, or larger portions of acid and 
 water may be mixed in these proportions. About three-fourths 
 of an ounce of bicarbonate of soda is heated strongly by a 
 lamp for a few minutes to obtain pure carbonate of soda (or, 
 what will do, take some crystals of soda and dry in a basin 
 until all the water is given off; when boiling has ceased, make 
 the heat to about a dull red ; this will give the soda salt), of 
 
126 
 
 TESTING SODA-ASH. 
 
 which 171 grains are immediately weighed, that quantity con- 
 taining 100 grains of soda; this portion of carbonate of soda 
 is dissolved in 4 or 5 ounces of hot water, and the alkalimeter 
 is filled up to the highest graduation with the dilute acid. 
 The acid is poured gradually into the soda solution till the 
 action of the latter upon blue litmus test-paper ceases to be al- 
 kaline and becomes distinctly acid, and the measures of acid 
 necessary to produce that change are accurately observed; say 
 it requires 90 measures. A plain cylindrical jar, of which the 
 capacity is about a pint and a half, is graduated into 100 parts, 
 each containing 100 grain measures of water, or ten times as 
 much as the divisions of the alkalimeter. This jar is filled up 
 with dilute acid to the extent of 90, or whatever number of the 
 alkalimeter divisions of acid were found to neutralize 100 
 grains of soda, and water is added to make up the acid liquid 
 to 100 measures. This forms a test acid of which 100 mea- 
 sures neutralize and are equivalent to 100 grains of soda, or 
 one measure of acid to one grain of caustic soda. This acid 
 ought to be kept in a well stoppered bottle. By a curious coin- 
 cidence, strong oil of vitriol diluted with 11 times its weight 
 of water, gives this test acid exactly; but, as oil of vitriol 
 varies a little in strength, it is better to form the test acid in 
 the manner described, than to trust to that mixture. Twenty- 
 one measures of the test acid should neutralize 100 grains of 
 crystalized carbonate of soda, and 68.5 measures of it should 
 neutralize 100 grains of pure anhydrous carbonate of soda. 
 
 To test a sample of soda-ash, 100 grains are weighed and 
 dissolved in two or three ounces of hot water. The alkalime- 
 ter is filled with the test acid, which is gently poured into 
 this solution, stirring, as each drop is added, until a piece of 
 blue litmus-paper, which may be kept in contact with the 
 liquor, is turned red. The number of graduations taken to 
 effect this indicates the percentage of caustic alkali in the 
 sample. 
 
 Another method of using test acid is by weight. The 
 acid is made to such a strength as one 
 Fig. 11. or two grains by weight will exactly 
 
 neutralize one grain of pure alkali. 
 The vessel commonly used for this 
 purpose is of the annexed form, but 
 any convenient vessel will do. It is 
 filled with the test acid, and the whole 
 correctly weighed. The acid is then 
 dropped from the small orifice into a 
 weighed quantity of the carbonate 
 until a neutral sulphate is produced, 
 
TESTING SODA-ASH. 
 
 127 
 
 indicated as above by test-paper. The bottle with its contents 
 is then again weighed ; the loss of weight gives, by calculation, 
 the quantity of real alkali in the sample. Say that every two 
 grains of the test acid are equivalent to one grain of pure soda, 
 and that twenty-five grains of soda-ash require twenty grains 
 of acid to neutralize it, the real alkali present will be ten. 
 Now 25 being the fourth of 100, the 10 is multiplied by 4, 
 giving 40 as the percentage of the sample. This method of 
 testing carbonated alkalies, provided the operator has a good 
 balance, is more correct than that with the graduated tube, and 
 equally simple. 
 
 Another very ready method, sometimes recommended, is to 
 take a small flask and a test-tube that will go inside, and stand 
 nearly straight. Fifty grains of the soda-ash are dissolved in 
 a little water in the flask, and the tube, which is nearly filled 
 with sulphuric acid, is carefully placed in the position shown 
 in the figure. A small chloride of calcium tube is fitted into 
 the mouth of the flask, and the whole is 
 then carefully weighed; after which, by Fig. 12. 
 
 holding the flask a little on one side, the 
 acid is poured from the tube into the 
 soda solution. This should be done 
 gradually, that the effervescence may not 
 be too violent. When all effervescence 
 ceases, and the flask is well-shaken, the 
 cork is taken out, that the rest of the 
 carbonic acid may freely escape; it is 
 then put back, and the flask is again 
 weighed ; the loss of weight will of 
 course indicate the loss of carbonic acid, and by this the quan- 
 tity of soda present may be calculated. If the loss of weight 
 be ten grains, then as 22 the equivalent of carbonic acid, is to 
 31 that of soda, so is 10 to 14.09, which, being multiplied by 
 2, there being only 50 grains of soda used, gives 28.18 as the 
 percentage of alkali in the sample. This method, however, is 
 not much to be relied upon in testing the value of alkali. 
 
 There are a great many other modes of proceeding, all em- 
 bracing the same principles as those detailed, and also a great 
 variety of apparatus for the purpose, but it is needless to men- 
 tion them. 
 
 It will be observed that the same principle applies to pot- 
 ash as to soda. In the* process where the loss of carbonic acid 
 is made the criterion, the difference is in the equivalents. The 
 equivalent of potash being 47.2, the proportion becomes 
 22 : 47.2 : : 10 x 2 : 21.45 X 2 = 42.9 per cent. With the 
 test acid process, there may be obtained an acid of such 
 
128 
 
 TESTING SODA-ASH. 
 
 strength that one graduation will be equal to one grain of potash, 
 which will be found in the same way as for soda, namely, by 
 neutralizing a known weight of pure dry carbonate of potash. 
 
 The operation most frequently tried, is performed by neu- 
 tralizing a given quantity of acid, which does for either soda 
 or potash. — Prepare a little pure anhydrous carbonate of soda 
 as described for the soda test ; weigh 53 grains, which is an 
 equivalent, and dissolve in water ; then take dilute acid in 
 the alkalimeter, and add it to the soda until it is perfectly neu- 
 tral; mark the number of graduations it takes for this ; say it 
 takes 30 ; then to every 30 of the acid add 70 of water, and 
 thus we have a stock acid, of which 100 graduations is equal 
 to an equivalent of any alkali. Thus — 
 
 100 graduations is equal to 31 grains caustic soda, 
 
 47.2 " " potash, 
 17 " " ammonia, 
 28 " " lime. 
 
 To test by this method, take 100 graduations of the test acid, 
 and weigh 100 grains of the alkali, and dissolve in 100 mea- 
 sures of water ; add this solution to the acid till it is neutral- 
 ized, and mark how many measures have been necessary to 
 effect this ; then the percentage of alkali is easily calculated. 
 Say that 70 measures of the alkali solution have been necessary 
 to neutralize the acid ; if the alkali is soda, then the 70 grains 
 of soda-ash will contain 31 grains of caustic soda ; and the 
 percentage is found by the following calculation : — 
 
 70 : 31 : : 100 : 44.3 per cent. 
 
 If the alkali is carbonate of potash, the 70 grains will contain 
 47.2 grains of caustic potash ; and then the percentage is found 
 by the proportion : — 
 
 70 : 47.2 : : 100 : 67.45 per cent. 
 
 For commercial salts, either of potash or soda, the mode of 
 testing by neutralizing is preferable to that which depends on 
 calculating from the loss of carbonic acid, as there are some- 
 times portions of caustic alkali in the sample which the car- 
 bonic acid process will not indicate. 
 
 It may also be observed that the acid test for soda, derived 
 from a coincidence in their equivalents, will serve equally well 
 for potash, each graduation being about 1 of caustic soda, and 
 1J of potash. 
 
 The process for making caustic soda from soda-ash, is the 
 same as described for making caustic potash, namely, a quan- 
 tity of ash is boiled, and, when boiling, slaked lime is added 
 
SULPHATE OF SODA. 
 
 129 
 
 until a small portion taken out does not effervesce on adding 
 an acid ; but the equivalent of soda being less than that of pot- 
 ash, it requires more lime for a given weight. 
 
 The following table, constructed by Dr. Dalton, will be found 
 useful to the operative bleacher, showing the quantity of caustic 
 soda in his solutions, indicated by the hydrometer : — 
 
 Specific 
 
 Alkali 
 
 Twaddell's 
 
 Specific 
 
 Alkali 
 
 Twaddell's 
 
 gravity. 
 
 per cent. 
 
 hydrometer. 
 
 gravity. 
 
 per cent. 
 
 hydrometer. 
 
 2.00 
 
 77.8 
 
 200 
 
 1.40 
 
 29.0 
 
 80 
 
 1.85 
 
 63.6 
 
 170 
 
 1.36 
 
 26.0 
 
 72 
 
 1.72 
 
 53.8 
 
 144 
 
 1.32 
 
 23.0 
 
 64 
 
 1.63 
 
 46.6 
 
 126 
 
 1.29 
 
 19.0 
 
 58 
 
 1.56 
 
 41.2 
 
 112 
 
 1.23 
 
 16.0 
 
 46 
 
 1.50 
 
 36.8 
 
 100 
 
 1.18 
 
 13.0 
 
 36 
 
 1.47 
 
 34.0 
 
 94 
 
 1.12 
 
 9.0 
 
 24 
 
 1.44 
 
 31.0 
 
 88 
 
 1.06 
 
 4.7 
 
 12 
 
 The remarks (page 117) in reference to the presence of 
 sulphurets in potash-lye injuring the gold ornaments of light 
 muslins, &c, are equally applicable here; and the same tests 
 for ascertaining the presence of these impurities in potash may 
 be employed to detect their presence in soda solutions. With 
 respect to the solubility of soda: — 
 
 100 parts water, at 62° 
 100 " 90° 
 
 100 " 131° 
 
 100 " 158° 
 
 100 " 176° 
 
 Cold water, saturated with soda, and brought to a boil, attains 
 a temperature of 266° Fah. 
 
 The salts of soda are in general* the same in their chemical 
 characters as the corresponding salts of potash, but they are 
 not so generally used, on account, perhaps, of the disposition 
 which almost all soda salts have to effloresce when exposed to 
 the air. 
 
 Sulphate of Soda. — Soda saturated with sulphuric acid, 
 forms sulphate of soda, which crystallizes easily, and is known 
 by the name of Glauber Salts. A dry and impure sulphate 
 of soda is sold under the name of salt cake ; it is obtained by 
 heating common salt and sulphuric acid in making hydrochloric 
 acid. It commonly contains about one-third of its weight of 
 salt. A purer sort of salt cake is obtained by the makers of 
 
 Fah. dissolve 41 parts of caustic soda. 
 " 64 
 
 " 72 " 
 u 78 « 
 
130 
 
 LITHIUM. 
 
 nitric acid ; in this process, the nitrate of soda is acted upon 
 by sulphuric acid, and the product being valuable, considerable 
 care is taken to have the nitrate decomposed. We have seen 
 salt cake, from this source, containing as much as 98 per cent, 
 of sulphate of soda. 
 
 Chloride of Sodium. — Hydrochloric acid, added to soda, 
 forms hydrochlorate of soda (muriate of soda) — more properly 
 chloride of sodium (common salt). The action is as follows : — 
 
 Hydrochloric acid j H ; Water 
 
 This salt is sometimes employed with nitric acid to make 
 the aqua regia used for dissolving tin. It is often amusing to 
 see the care taken to mix the acid and the soda to form what 
 may be got so conveniently as common salt. 
 
 Nitrate of Soda.— Nitric acid, added to soda, forms nitrate 
 of soda. This salt, as already stated (page 62), is found 
 abundantly in nature, and is termed cubic nitre, from the shape 
 of its crystals, and to distinguish it from nitrate of potash 
 {nitre). When heated to redness, it is decomposed, and gives 
 off much oxygen gas ; it is often employed for this purpose, 
 and for oxidizing metals in a fused state. It is also occasion- 
 ally used for preparing some of the salts of tin for mordants, 
 along with hydrochloric acid. 
 
 Borate of Soda. — Boracic acid, with soda, forms borate 
 of soda [borax or tinkal). This, as we have before noticed, 
 (under Boron), is also a natural product; it is used as a blow- 
 pipe reagent for fluxing metals. 
 
 Phosphate of Soda. — Phosphoric acid, with soda, forms 
 phosphate of soda, also a useful salt, as a test for the presence 
 of magnesia in water solutions. 
 
 Soda, on account of its cheapness, has been substituted for 
 potash in the manufacture of some of the salts most extensively 
 used, such as ferrocyanides, chromates, alum, &c, but none 
 of these modified salts have come into common use, not that 
 they are less suitable in the dye-house, but for other reasons 
 which we need not here examine. 
 
 Soda, Na 
 
 Chloride sodium. 
 
 Lithium (L 6.5). 
 
 This is another alkaline metal, the oxide of which is termed- 
 Lithia. It has properties somewhat resembling those of soda 
 and potash, and combines with acids as a base in the same man- 
 
SOAP. 
 
 131 
 
 ner as these other alkalies. It is, however, very rare, and only 
 got in small quantities, from a mineral termed Lepidolite. It 
 has not, as yet, been used in any process of manufacture, and 
 has therefore no claim to our farther consideration. 
 
 Soap. 
 
 In connection with the alkalies, it will be necessary to direct 
 attention to Soap, an article of great importance in the dye- 
 house. If we take a quantity of oil, and add to it some caus- 
 tic alkali, a milk-white solution is obtained, which is found to 
 be soluble in water. This solution, boiled down to a proper 
 consistence and cooled, forms soap. All sorts of fats and oils 
 are used in soap-making ; they all contain certain acids, capable 
 of combining with the alkali, and giving a detersive character 
 to the compound. The soap made with soda is hard, that with 
 potash soft; and the degree of hardness, in either case, varies 
 according to the nature of the oil or fat employed. In manu- 
 facturing soap, care is taken to obtain a proper mixture of 
 these fats and oils, so as to produce a soap of proper consist- 
 ence. The following extract on this subject from Normandy's 
 Commercial Handbook of Chemical Science, is important: — 
 
 * Mottled soap has a marbled or streaky appearance ; that 
 is to say, veins of a bluish or slate color pervade its mass, 
 which is white or whitish; the size and number of these veins 
 depend on the more or less rapid cooling of the soap after it 
 has been transferred from the copper to the frames. The blue 
 or slate color of these streaks is chiefly due to the presence of 
 an alumino-ferruginous soap interposed in the mass, and fre- 
 quently, also, to that of sulphuret of iron, which is produced 
 by the reaction of the alkaline sulphurets, contained in the 
 soda-lye, upon the iron, derived from the iron, copper, and 
 utensils employed in this manufacture, or, which even is, at 
 times, introduced purposely as sulphate of iron. The veins 
 gradually disappear from the surface to the centre, by keeping, 
 by the oxidation of the sulphuret of iron. A well manufac- 
 tured mottled soap cannot contain more than 33, 34, or, at 
 most, 36 per cent, of water. The addition of water causes the 
 color to subside, and a white soap is produced. This addition 
 of water is made when the object is to give white soap ; so 
 that, with this additional quantity of water, white soap some- 
 times contains 55 per cent. It is therefore best to buy mot- 
 tled soap in preference to yellow or white soap, the mottling 
 being a sure criterion of genuineness, as the addition of water 
 or other matters would soon destroy the mottling." — This 
 
132 
 
 SOAP. 
 
 quality of soap is not much known in Scotland ; even the name 
 is not used. " To yellow or white soap," says Mr. Normandy, 
 i£ incredible quantities of water may be added. I have known 
 15 gallons of water added to a frame of already fitted soap (10 
 cwt.), so that the soap, after this treatment, contained upwards 
 of 60 per cent, of water. Common salt had been previously 
 dissolved in the liquor. 
 
 "Besides being surcharged with water, soap is sometimes 
 farther adulterated with gelatin, made by boiling bones, 
 sinews, hoofs, skins, fish, &c. ; in alkalies; also with dextrine, 
 potato-starch, pumice-stone, silica, plaster of Paris, clay, salt, 
 chalk, carbonate of soda, &c. &c." 
 
 Soft, or black soap, is the most useful of all the soaps. It is 
 made with fats or oils and a solution of potash, and always 
 contains a great excess of alkali' and much water ; also chlo- 
 rides, sulphates, and other impurities. Fish oil is also often 
 employed in the making of this soap, which gives it a very 
 disagreeable smell. Soft soap, which has a greenish color, is 
 best, although occasionally this color is given to a very inferior 
 article, by the addition of a little indigo. 
 
 The quantity of water in soap may be ascertained by taking 
 100 grains of the sample in thin parings, putting them into a 
 water-bath or oven, of which the heat does not exceed 212°, 
 and allowing them to stand as long as they continue to lose 
 weight, which is known by occasional weighing; the loss of 
 weight indicates the water evaporated. In mottled soap, it 
 should not exceed 35 per cent. ; in the white and yellow soaps, 
 it ought not to be more than 50 per cent. 
 
 The other impurities of soap may be detected by dissolving 
 100 grains in strong alcohol, and applying a gentle heat ; the 
 soap is thus dissolved, and the impurities remain as precipitate. 
 The best soap should not contain above 1 per cent, of matter 
 insoluble in alcohol. Good soap may be known by its com- 
 parative transparency. When cut thin, the purer the soap is 
 the more translucent. Dry soap is also more transparent than 
 wet. 
 
 The earths combine, also, with fats and form soaps, some of 
 which are difficultly soluble in water, so that if there be oil 
 or grease upon goods, and they are put into matters that form 
 an insoluble or difficultly soluble soap, these spots will be so 
 many white stains in the dyed goods ; and when ordinary soap, 
 made from fats, is put into water that has earthy matters or 
 salts in it, these salts are decomposed by the alkali of the soap 
 taking the acid, and greasy or insoluble soapy spots are pro- 
 duced. This is often experienced in washing with soap in hard 
 water; these spots are sources of annoyance to the dyer. 
 
SOAP. 
 
 133 
 
 When soap is dissolved in water, there should be no oily or 
 fatty matter visible on the surface, as this would indicate that 
 too little alkali had been used in the manufacture of the soap. 
 The following method of testing the quality of soaps is given 
 by M. Dumas, in the Chimie Appliquee aux Arts, tome vi. : — 
 
 "To determine the quantity of water, thin slices are^ut 
 from the edges and from the centre of the bars. A portion is 
 then weighed, about 60 to 70 grains, and exposed to a current 
 of air, heated at 212° F., or in an oil-bath, until it ceases to 
 lose weight. The dry substance is then weighed ; the difference 
 between the first and last weighing will indicate the quantity 
 of water evaporated. If it be a soft soap, it is weighed in a 
 counterpoised shallow capsule. In good soap, the amount of 
 water varies from 30 to 45 per cent., in mottled and soft soaps, 
 from 36 to 52 per cent. 
 
 "The purity of soap may be ascertained by treating it with 
 • hot alcohol ; if the soap be white, and without admixture, the 
 portion remaining undissolved is very minute, and a mottled 
 soap of good quality does not leave more than about 1 per 
 cent. 
 
 "If there should be a sensible amount of residue from white 
 soap, or more than 1 per cent, from mottled soap, some acci- 
 dental or fraudulent admixture may be suspected, silica, alu- 
 mina, gelatin, &c, the quantity and nature of which may be 
 determined by analysis. 
 
 "The quantity of alkali contained in the soap is easily de- 
 termined by means of the alkalimeter; a known quantity of 
 the soap is dissolved in water, and tried by the test acid. 
 
 "There is no difficulty in ascertaining in the same assay the 
 quantity of the fatty substance. For this purpose, 150 grains 
 of pure white wax, free from water, are added to the liquid 
 after saturation with the test acid, and the whole heated to 
 complete liquefaction ; it is then allowed to cool, and when it 
 has become solid, the cake of wax and fatty matter which have 
 united is removed and washed, dried, and weighed ; the aug- 
 mentation in weight beyond the 150 grains employed will give 
 the weight of the fatty matter. 
 
 " The liquid decanted from the solidified wax may after- 
 wards be tested to ascertain the purity of the base. 
 
 "The solution of the sulphate may also be evaporated, and 
 by an examination of its crystalline form, or by means of chlo- 
 ride of platinum, it may be ascertained whether the base be 
 soda or potash, or a mixture of the two. 
 
 " As to the nature of the fatty substance, it is ascertained, 
 with more or less certainty, by saturating the solution of the 
 soap with tartaric acid, collecting the fat acids, and taking their 
 
184 
 
 BARIUM. 
 
 point of fusion. It is possible, at least, by this to prove the 
 identity, or the absence of identity, with the sample in the soap 
 supplied ; for instance, whether it is made from oil or tallow, 
 &c. The odor developed by the fatty acids, at the moment 
 of the decomposition of the soap by acids assisted by heat, 
 will often indicate the nature of the fatty substance employed 
 in Its fabrication, or that at least of which the odor may 
 prevail. 
 
 " The soap is proved to contain an excess of fatty matter 
 not saponified, by separating the fatty acids by means of hy- 
 drochloric acid, washing with hot distilled water, then com- 
 bining them with baryta, and thoroughly washing the new 
 compound with boiling water. The non-saponified fatty mat- 
 ter is easily separated from the barytic soap by treating the 
 mass with boiling alcohol, which dissolves the fatty substance. 
 We can, moreover, assure ourselves that it has no acid reac- 
 tion on moistened litmus-paper, that it is fusible, and that it 
 possesses the general characters of a neutral fatty substance." 
 
 Barium (Ba 68.5). 
 
 This is a metal having a silver- white lustre, and considerable 
 ductility ; it is four times heavier than water, rapidly oxidates 
 when exposed to the air, forming Barytes, one of those sub- 
 stances termed earths, and which has strong alkaline properties. 
 This earth, which was decomposed and its metallic basis dis- 
 covered by Sir H. Davy in 1808, exists abundantly in nature, 
 in combination with sulphuric acid, forming sulphate of barytes 
 (heavy spar), and with carbonic acid forming carbonate of 
 barytes. The artificial salts are generally prepared from the 
 sulphate, which is ground fine, mixed with charcoal, and kept 
 at a strong red heat in a crucible for about an hour. Sulphuret 
 of barium is thus formed. This is now acted upon by nitric 
 or hydrochloric acid, to form the nitrate or chloride, according 
 as one acid or the other is used. These salts may also be ob- 
 tained from the carbonate without previous heating, by merely 
 digesting the mineral in the acid. 
 
 Chloride of Barium is a crystalline salt, of which 100 
 parts of cold water dissolve about 43 parts. 
 
 Nitrate of Barytes is also a crystalline salt, but not so 
 soluble in water ; 100 parts of cold water dissolve only about 
 8 J parts of it. The affinity of barytes for sulphuric acid is very 
 great ; it takes it from every soluble substance, and forms with 
 it an insoluble precipitate. Hence it is that barytes is pre-emi- 
 nently the test for sulphuric acid. 
 
STRONTIUM — CALCIUM. 
 
 135 
 
 The Acetate of Barytes is sometimes used to precipitate the 
 sulphuric acid of alum, and form an acetate of alumina; but 
 this use of the salt is not very extensive. 
 
 Strontium (Sr 43.8). 
 
 This is a metal very similar to Barium in appearance and 
 properties. Its oxide is termed Strontia. It is another of the 
 earths which has alkaline properties, and which occurs in na- 
 ture in combination with carbonic and sulphuric acids, although 
 not very abundantly. The artificial salts are prepared from 
 the carbonate, by acting upon it with nitric or hydrochloric 
 acid, by which is formed nitrate of strontia or chloride of 
 strontium, both crystallizable salts. Its solutions precipitate 
 sulphuric acid, but not so fully as the solutions of barytes. 
 The salts of strontium are not used in manufactures, except 
 indeed for fireworks; they have the property of communicating 
 a red color to flame. 
 
 Calcium (Ca 20). 
 
 This is a metal of which the oxide is Lime — one of the most 
 widely diffused of all the earths, and also one of the most gene- 
 rally useful. It exists in nature as a carbonate and as a sul- 
 phate. Ordinary limestone, chalk, marble, &c. are carbonates : 
 gypsum, plaster of Paris, &c. are sulphates. 
 
 Caustic Lime is obtained by heating the carbonate to red- 
 ness — which is the ordinary process of lime-burning in a kiln. 
 The carbonic acid is driven off, and caustic or burned lime 
 remains. The caustic lime combines rapidly with one equiva- 
 lent of water, and, becoming a hydrate, falls into a fine pow- 
 der, commonly termed slaked lime. During this operation, 
 much heat is evolved from the water as it passes from a fluid 
 to a solid state in combining with the lime, and gives out its 
 heat of fluidity. 
 
 Lime is soluble in water, producing lime-water, which has 
 an alkaline reaction, much valued in the dye house. It takes 
 78 gallons of water at 60° to dissolve one pound of lime ; 97 
 gallons at 130° ; and 127 gallons at 212°. 
 
 Thus we see that cold water dissolves more lime than hot 
 water ; so the practice of putting boiling water into lime, in 
 order to get a strong solution, is erroneous ; and when a boiler 
 is filled with cold lime-water, and brought to boil, as when 
 oranges are to be raised, we see why there is always a quantity 
 of powder deposited ; for, as the hot water does not hold the 
 
136 
 
 MAGNESIUM. 
 
 same quantity of lime in solution as the cold, the surplus is 
 deposited in fine crystalline grains. Lime-water, exposed to 
 the air, absorbs carbonic acid rapidly, forming a thin pellicle 
 on the surface, which, falling down from time to time, the lime 
 in the solution will ultimately be all deposited. Lime, in its 
 caustic state, is extensively used in the dye-house, and we will 
 hereafter have occasion to refer to it when describing the 
 operations of the trade. 
 
 Lime combines with the acids, forming a series of salts of 
 little practical use to the dyer. With hydrochloric acid it 
 forms the chloride of calcium — a very deliquescent salt, which 
 is sometimes on that account used in absorbing moisture from 
 gases, &c. It is formed in the spontaneous decomposition of 
 bleaching powder, which it makes damp. (See page 81.) 
 
 Sulphate of Lime is an insoluble substance, or nearly so, 
 the acid and lime having a strong affinity for each other. This 
 salt is formed in the common blue vat by the sulphate of iron. 
 It is held in solution in very minute quantities in some spring 
 waters. 
 
 Carbonate of Lime [Limestone) is soluble in water holding 
 carbonic acid, probably forming a bicarbonate of lime. 
 
 The best test for the presence of lime is a solution of oxalate 
 of ammonia, which gives with lime a white precipitate. 
 
 Magnesium (Mg 12). 
 
 This is a silver- white metal, ductile and hard, and oxidates 
 rapidly when exposed to moist air and in water. 
 
 Magnesia. — The oxide is the well-known alkaline earth 
 magnesia, which, having a low combining equivalent, is re- 
 markable for its great power of saturating acids. Magnesia is 
 abundant in nature, but it is found chiefly in the state of car- 
 bonate. There are immense beds of it in combination with 
 lime, termed magnesian limestone. The carbonate is soluble 
 in water, which contains free carbonic acid, and imparts to the 
 water a slightly alkaline reaction. Magnesia combines with 
 the acids, and forms with them a series of salts of considerable 
 importance in several manufactures and in medicine, but they 
 are not much used in dyeing. The salt principally used is 
 the sulphate (Epsom salt), which exists in certain springs, and 
 is easily prepared by saturating magnesia or carbonate of mag- 
 nesia, with sulphuric acid, and evaporating the solution to 
 crystallize the salt. Salts of magnesia in water are very bad 
 for delicate colors. The best test for its presence is phosphate 
 of soda, with which, after long stirring, it gives a white pre- 
 cipitate, even with very minute quantities. 
 
ALUMINUM. 
 
 137 
 
 The five elements — Glucinum or Beryllium, Yttrium, Tho- 
 rium, and Aluminum — have been termed the metals or bases 
 of the earths proper, to distinguish them from the four elements 
 we have just been considering; these, from having alkaline 
 properties, have been termed the alkaline earths. The first 
 named three elements of the earths proper are very rare, and 
 their characters have been studied by very few chemists; 
 accordingly, little is known about them, and as no practical 
 application has been made of any of them or their salts, we 
 may dismiss them with this brief notice. But the fourth, 
 namely, aluminum, is of vast importance, and consequently 
 demands special attention. 
 
 Aluminum (Al 13.7). 
 
 Aluminum is a white metal, very ductile and tenacious. Its 
 point of fusion is below that of silver. Remarkable by its 
 low specific gravity (2.56 to 2.67), this metal is little acted 
 upon by oxygen. Its true solvent is muriatic acid ; nitric and 
 sulphuric acid dissolve it only when hot and concentrated. 
 
 Alumina. — There is only one oxide of aluminum known, 
 which is a sesquioxide, Al 2 0 3 . This is termed alumina, 
 which is the pure plastic principle of clay, and is exceedingly 
 abundant in nature as such. It combines with acids, forming 
 salts, but it only combines in the proportions stated: thus ; by 
 dissolving alumina in hydrochloric acid there is formed — 
 
 Alumina ....... ^jj 
 
 3 Proportions hy- ( 3 H. 
 drochloric acid ( 3 CI 
 
 Alum. — Alumina is easily dissolved in sulphuric acid, form- 
 ing the sulphate of alumina, which crystallizes with much 
 difficulty ; but this salt has a strong affinity for the sulphate 
 of potash; so that when these two salts are mixed, or when a 
 salt of potash is added to a strong solution of sulphate of alu- 
 mina, they combine, and form common alum, which is easily 
 crystallized. That is what chemists denominate a double salt, 
 being composed of two sulphates — the sulphate of alumina 
 and the sulphate of potash. This salt has been known, and in 
 general use among dyers, since the earliest accounts we have 
 of their processes; but the true nature of its composition was 
 not known till the present century. The alchemists knew 
 that sulphuric acid was one of its constituents; and during the 
 last century, it was discovered that the precipitate which falls 
 
 3 Water. 
 
 Chloride of aluminum. 
 
138 
 
 ALUM. 
 
 when the acid is neutralized by an alkali, is a particular kind 
 of earth which chemists called alumina, because of its being 
 obtained from alum. Amongst other peculiar properties of 
 alumina, it has a strong attraction for organic matter, and 
 withdraws it from solutions with such force, that if the purest 
 water be not used when preparing it, the alumina is colored; 
 and when digested in solutions of vegetable coloring matters, 
 provided the alumina be in sufficient quantity, it will carry 
 down all the coloring matter from the liquid. By this means 
 the pigments called lakes are formed; and it is this that makes 
 it so valuable as a mordant. The fibre of cotton, when charged 
 with this earth, attracts and retains coloring matters. 
 
 A very pure alum is obtained in the Eoman States from 
 alum stone, a mineral which is continually produced at the Sol- 
 fatara, near Naples, and other volcanic districts, by the joint 
 action of sulphurous acid and oxygen upon some of the feld- 
 spathic rocks. This mineral contains an insoluble subsulphate 
 of alumina, with sulphate of potash ; but it is partially decom- 
 posed by heat; so that, for the preparation of alum, the 
 mineral is simply heated, till sulphurous acid begins to escape, 
 and is then treated with water, by which process a very pure 
 and excellent alum is procured — much superior to that manu- 
 factured in this country. The alum of this country is manu- 
 factured from a mineral termed alum shale, a kind of clay slate, 
 much impregnated with sulphuret of iron, which is essential to 
 the manufacture. The general composition of this alum ore, as 
 it is also called, is as follows, observing that the proportions of 
 the several components vary according to the depth from which 
 the ore is obtained ; the table is therefore to be considered as 
 giving only the average constitution : — 
 
 The ore is built up in large heaps, with alternate layers of 
 coal ; these heaps are set on fire, and allowed to burn for several 
 weeks. During this roasting process, a portion of the sulphur 
 is expelled, but the greater portion of it is converted first into 
 sulphurous acid, by taking an equivalent of oxygen from the 
 
 Sulphuret of iron . . 
 Oxide of iron . . . 
 
 Alumina 
 
 Silica 
 
 Lime 
 
 Magnesia, potash, soda 
 Coaly matter . . . 
 Water 
 
 26.5 
 3.1 
 
 18.3 
 
 10.5 
 3.0 
 1.4 
 
 28.7 
 8.5 
 
 100.0 
 
ALUM. 
 
 139 
 
 atmosphere, and finally into sulphuric acid, by taking a farther 
 proportion from the peroxide of iron contained in the mineral. 
 The sulphuric acid does not, however, remain isolated, but 
 combines with the iron and alumina, and forms sulphates with 
 these oxides. The roasting being completed, the material of 
 the heap is removed to large tanks or pits, into which water is 
 allowed to flow, and which dissolves out the sulphates formed 
 in the process. The solution is run into large tanks and evapo- 
 rated, generally by causing a current of dry heated air to pass 
 over the surface of the liquid. When the solution is in this 
 way sufficiently concentrated, the sulphate of iron crystallizes, 
 and is then removed ; the sulphate of alumina, being very diffi- 
 cult to crystallize, remains in solution. All the iron having by 
 this means been separated, the sulphate of alumina in solution 
 is removed to other vessels, where there is added to it sulphate 
 of potash, chloride of potassium, or other salts of potash. There 
 is then formed the double salt of potash and alumina, which is 
 alum, and which, after a few days' standing, crystallizes, and 
 is removed and packed for the market. There are some modi- 
 fications of this process adopted by different makers, but this 
 description exhibits the general practice of the manufacture, 
 and illustrates sufficiently the principle upon which the prac- 
 tice is necessarily based. 
 
 Soda may be used in the operation instead of potash, which 
 would give a soda alum, but, notwithstanding its being cheaper, 
 there are practical objections to it. Soda alum is not so easily 
 crystallized as common alum, and it effloresces when exposed 
 to the air, which makes it take the appearance of a dry powder. 
 Sulphate of ammonia may also be used instead of potash, 
 giving an ammonia alum, which, however, is expensive, and 
 possesses no corresponding advantage over the ordinary article.* 
 
 The following analysis, by Dr. Thomson, of the alum made 
 in this country, will be useful : — 
 
 Potash .... 9.86 1 G , , 
 
 Ai ii no i Symbols. 
 
 Alumina . . ii.ua l A 1 0 3 3 S0 3 + KO S0 3 + 24 HO. 
 Sulphuric acid . 32.85 f * 3 3 3 
 Water .... 46.20 J 
 
 100.00 
 
 Thus, every 100 lbs. of alum contain 46 lbs. of water. From 
 the nature of the processes by which the alum is manufactured, 
 we may expect it to contain small traces of sulphate of iron, a 
 substance very deleterious to its use as a mordant or alterant. 
 
 * Most of the alum now made is ammonia alum. 
 
140 
 
 ALUM. 
 
 Iron may be detected by dissolving a little of the salt in dis- 
 tilled water, and adding a few drops of a solution of red prus- 
 siate of potash ; or boiling a little, with the addition of a few 
 drops of nitric acid, and adding yellow prussiate of potash. In 
 both cases, a deep blue color is immediately produced, if iron 
 is present. The addition to a solution of alum of a few drops 
 of gallic acid will give a black color, if iron be present. Or, 
 if a little alum be put into a vessel, and caustic potash added 
 till the solution is strongly alkaline, then the whole boiled, and 
 set aside to cool and settle, the alumina will be dissolved, and, 
 if iron be present, it will subside to the bottom as a brownish 
 precipitate. When the proportion of iron is considerable, it is 
 better to reject the alum altogether, especially for bright light 
 shades. We have often experienced bad effects from the use 
 of such alum upon light shades of drab or fawn colors, when 
 dyeing to a particular pattern. Having obtained the particular 
 shade, on adding a little alum as raising, the iron, by combining 
 with the sumach upon the cloth, produced a color two or three 
 shades darker than required ; leaving no alternative but to take 
 off the color and dye anew — a process much more difficult, and 
 'which produces a color much less brilliant than the first. 
 
 Pure alum is soluble in water, and should give a colorless 
 solution. 
 
 One gallon of water at 54° Fahr. dissolves 1 lb. alum. 
 One " " 86 " " 2 " 
 
 One " " 140 " " 3 " 
 
 One " " 158 " " 9 " 
 
 One " " 212 " " 35 " 
 
 Alum forms but a weak mordant for cotton goods, owing to 
 the strong attraction which the' sulphuric acid has for the alu- 
 mina; and in this state there are three proportions of acid to 
 every two of alumina. But if we neutralize a portion of the acid, 
 so that no more remains than is necessary to hold the alumina 
 in solution, which, according to experiment is not above a third 
 of the acid contained in common alum, its properties as a mor- 
 dant are greatly improved. That the amount of acid admits 
 of being reduced, may be proved by taking a quantity of car- 
 bonate of soda, sufficient to neutralize the whole of the acid 
 contained in a given portion of alum, dividing the soda solu- 
 tion into three equal portions, and adding gradually to the 
 aluminous solution (stirring all the time) two of these portions ; 
 it will be found that, although the alumina is at first precipi- 
 tated, by keeping up the agitation for some time, the precipitate 
 again dissolves, forming an alum containing only a third of the 
 acid of common alum. In this state, alum is a more powerful 
 
ACETATE OF ALUMINA. 
 
 141 
 
 mordant for cotton, as the base is held more feebly by the sul- 
 phuric acid, and is readily detached by the superior affinity of 
 the cloth to form a mordant; and, thus prepared, it is perfectly 
 pure; any iron formerly present is precipitated in the process. 
 Alum in this state is known by the name of cubical or basic 
 alum, from the form in which it crystallizes. We have already 
 referred to Eoman alum being superior to other alums. For a 
 long time, the dyers considered this superiority to be wholly 
 owing to its purity ; but a chemical investigation shows it to 
 be caused by the small quantity of acid it contains in compari- 
 son with ordinary alum. 
 
 Sulphate of Alumina. — The useful principle of alum is 
 sulphate of alumina. Several attempts have been made to in- 
 troduce this substance in the practice of dyers, which have 
 failed on account of the sulphate of iron remaining, and es- 
 pecially in consequence of a large excess of sulphuric acid in 
 the sulphate, which it was necessary to neutralize, otherwise 
 the alumina would not have had enough affinity for the fibre. 
 At the present day, these defects have been overcome, and a 
 neutral sulphate of alumina is to be found in the market, which, 
 for a given weight, contains more alumina than alum. 
 
 Alum Cake is kaolin or pure clay treated by sulphuric acid, 
 and heated until dry. It is a mixture of silica and sulphate of 
 alumina. 
 
 Aluminate of Soda. — This substance, which begins to be 
 used as a mordant, is prepared directly from the mineral kryo- 
 lite, which is deprived of its fluorine by the addition of lime ; 
 or from another mineral, called bauxite, which is an aluminate 
 of iron. By a calcination with carbonate of soda, the iron is 
 eliminated, and the aluminate of soda is lixiviated, and evapo- 
 rated to dryness. 
 
 By a sufficient quantity of hydrochloric acid, the soda is 
 separated, and the hydrated alumina which is left is soluble in 
 acetic acid. It is therefore possible by this means to make a 
 very pure acetate of alumina. A sample of commercial alu- 
 minate of soda, from the bauxite contains: — 
 
 Acetate of Alumina. — The most common and, we believe, 
 the best method of using alumina as a mordant, is by substi- 
 tuting acetic acid for sulphuric acid as its solvent. The acetate 
 of alumina has several advantages over the sulphate : 1st, the 
 
 Soda 
 
 Alumina 
 
 Sulphate of soda and chloride of sodium . 
 
 43 
 48 
 9 
 
 100 
 
142 
 
 ACETATE OF ALUMINA. 
 
 acetic acid is not so hurtful in its action upon the vegetable 
 coloring matter; 2d, it holds the alumina with much less force 
 than sulphuric acid, and consequently yields it much more 
 freely to the cloth ; and, 3d, being volatile, a great portion of 
 the acid flies off during the process of drying. When strong 
 colors are wanted, and the mordant is of such a nature as will 
 admit of being dried, it is better to dry the cloth from the 
 mordant previous to dyeing. This last property of acetic acid 
 is very convenient, as it frees the cloth from any superfluous 
 acid which may have been in the mordant ; besides, it has been 
 found that, during the drying by heat, the soluble acetate is 
 converted into a less soluble subacetate. We may here put the 
 dyer in mind, that when goods containing volatile acids are 
 drying, no other goods should be allowed to be in the same 
 apartment, as the acid will be absorbed by them, and will affect 
 almost any color that either has been or may be put upon them. 
 Many unpleasant and also expensive consequences occur from 
 the neglect of these precautions. 
 
 The acetate of alumina is easily prepared by mixing a solu- 
 tion of acetate of barytes, lime, or lead with alum. When any 
 of these salts are added to alum, a double decomposition takes 
 place ; the sulphuric acid of the alum combines with the base 
 of the salt which falls to the bottom, and the acetic acid unites 
 * with the alumina, forming acetate of alumina, which remains 
 in solution mixed with sulphate of potash, which formed a 
 constituent of the alum. The acetate of lead is the salt ge- 
 nerally used for this purpose in the dye-house; the proportions 
 of the lead and alum vary according to the nature of the color 
 to be dyed and the peculiar taste of the dyer, for the prepara- 
 tion of this substance is one of those operations which every 
 one who practises it thinks he has the best method, but so far 
 as we have had an opportunity of knowing, the superiority only 
 existed in the mind of the individual, or, rather, in its being 
 kept secret. In the proportions used for the preparation of 
 this mordant, there is never a sufficient quantity of acetate of 
 lead to precipitate all the sulphuric acid in the alum. This 
 crystallized acetate of lead has an equivalent of 190, and that 
 of alum crystals of 475 ; but the alum having 4 equivalents of 
 sulphuric acid, would require 4 equivalents of acetic acid to 
 take its place. Thus : — 
 
 2 Al. 
 
 3S0 4 
 
 „Acetate of alumina. 
 
ACETATE OF ALUMINA. 
 
 143 
 
 So that the equivalent of acetate of lead 190 must be multi- 
 plied by 4, giving 760, to be equal to 475 of alum. These are 
 far from the proportions used, showing that the mordant is not 
 a pure acetate of alumina, but a mixture of salts, probably of 
 cubic alum with acetate of alumina and sulphate of potash. 
 
 The following method we have generally found to answer 
 very well : Into a boiler or pot put 20 lbs. of crystallized alum 
 with about nine gallons water, and boil till the alum is com- 
 pletely dissolved. In a separate vessel dissolve 20 lbs. of ace- 
 tate of lead in about three gallons of boiling water. This is 
 added to the alum while at a boiling heat, and well stirred. 
 The sulphuric acid combines with the lead, forming an insoluble 
 sulphate of lead, which falls to the bottom as a heavy white 
 precipitate; the soluble part constitutes the mordant. The 
 difference in the preparation of this mordant is in the propor- 
 tion of lead varying from one-half of the alum to equal weights. 
 There is also added to the alum and lead a quantity of carbon- 
 ate of soda, varying from four to eight ounces to the five pounds 
 of alum. This is added for the purpose of neutralizing a por- 
 tion of the acid ; but there are many dyers who will not use 
 soda or any other alkaline substance when light bright shades 
 are wanted, under the impression that the color is much brighter 
 without alkalies ; but the difference of hue is hardly percepti- 
 ble ; some use lime ; soda, however, is best. Without soda or 
 some other alkaline substance, the mordant is not so effective. 
 There are also some who object to the use of soda, as it throws 
 down the alumina ; but we have already noticed that a very 
 little acid holds the alumina in solution ; so that although soda, 
 when added to the acetate of alumina, appears to precipitate 
 the alumina, by a little agitation the precipitate is again dis- 
 solved, forming a mordant better adapted for strength of color. 
 From the following recipes, taken from a French work on dye- 
 ing, it will be observed that the quantities of the aluminous 
 mordants are similar both in England and France : — 
 
 60 gallons boiling water, ^ 
 100 pounds of alum, ! This mordant is best 
 
 100 pounds acetate of lead, [ adapted for reds. 
 
 10 pounds crystallized soda, J 
 
 80 gallons boiling water, \ 
 100 pounds alum, ( This is best for bright 
 
 50 pounds acetate of lead, j yellows. 
 
 „ 6 pounds soda, J 
 
 In addition to the above, Dr. Ure, in his Dictionary of the 
 Arts and Manufactures, article "Calico-Printing," gives another 
 proportion : — 
 
144 
 
 ACETATE OF ALUMINA. 
 
 50 gallons boiling water. 
 100 pounds alum. 
 75 pounds acetate of lead. 
 10 pounds soda. 
 
 The following curious phenomenon was observed by Gay- 
 Lussac, viz., that the solution of a pure salt of the acetate of 
 alumina may be boiled without decomposition ; but if sulphate 
 of potash, or any other neutral salt of an alkali be present, the 
 solution becomes turbid when heated, and a basic salt precipi- 
 tates, which dissolves again on cooling. Now the acetate of 
 alumina, prepared from the common alum, always contains 
 sulphate of potash. If by the presence of this salt a portion 
 of the acetate of alumina be thrown down when hot, and 
 incorporated with the sulphate of lead, which falls in a very 
 dense state, it may there be lost to the dyer. Whether this 
 be so we know not, as we have not, since we knew of this 
 phenomenon, had an opportunity of putting it to the test ; but 
 it would be advisable to stir the whole after becoming cold, 
 that if any of this basic salt should be bound up with the pre- 
 cipitate, it might be set at liberty and dissolved; but it must 
 be borne in mind, that if this be stirred when cold, it takes a 
 long time to settle. 
 
 Nearly all the acetate of alumina used in dyeing, is pre- 
 pared from pyroligneous acid, and is called by calico-printers 
 red liquor, but by dyers mordant. No other substance, what- 
 ever be its nature, is distinguished as a mordant. All other 
 mordants have their technical names. The pyroligneous acid 
 is one of the products of the destructive distillation of wood. 
 The hard woods, such as oak, ash, birch, and beech, alone are 
 used ; they are put into large cast-iron cylinders, so constructed 
 that a fire plays about them so as to keep them at a red heat, 
 and having openings through which all volatile matter escapes 
 by pipes, which lead into condensing vats. The products thus 
 obtained consist principally of pyroligneous acid, mixed jkith 
 a black tarry matter, having a very strong smell, from wfrlch 
 the acid had its name, although it has been long since known 
 that it is simply acetic acid (vinegar). There is a great variety 
 of other substances present, some of which have very singular 
 properties, and some of the continental chemists suppose, they 
 might be made available in dyeing. The products of the dis- 
 tillation of the wood are allowed to stand for some time, aftpr 
 which as much of the tarry matter as swims is skimmed off; 
 the remainder is filtered, after which it is put into a boiler and 
 heated a little, and lime added by degrees, till the acid is neu- 
 tralized ; then a quantity of lime is added in excess, and the 
 
♦ 
 
 ACETATE OF ALUMINA. 145 
 
 whole is made to boil; this throws up the tarry matter to the 
 top, where it is taken off. When it is purified as much as it 
 can be by this means, it is siphoned off into another boiler, 
 and a quantity of alum is added ; the acetate of lime, the sul- 
 phate of alumina and potash, mutually decompose each other; 
 the sulphate of lime falls to the bottom, and the acetate of alu- 
 mina remains in solution, which, when sent to the dyers, has 
 sometimes a specific gravity of 1.90 (18 Twaddell), although it 
 is often weaker, ranging from 12 to 18 Twaddell. It has a 
 dark-brown color, and a very strong pyromatic odor. When 
 the acetic acid is wanted pure, it passes through a number of 
 other .processes, which do not come within our province to 
 describe in this place. 
 
 There is a considerable difference in the quality of red liquor, 
 which the mere specific gravity does not indicate, as this can 
 be brought up by the addition of foreign matters, such as Bri- 
 tish gum, dextrine, and such like. A very simple method may 
 be adopted to test the effective quality of the mordant : Take 
 a little of the liquor, and evaporate it to dryness, then burn the 
 residue at a red heat until white in color ; put this into dis- 
 tilled water, which will dissolve out all but the alumina. 
 Another way is by digesting a little of the red liquor in nitric 
 acid, adding ammonia until the liquor smells of it, and then, by 
 filtering, the alumina is obtained upon the filter-paper. We 
 will add four varieties here, to show the variableness in quality 
 of the liquor as supplied to the dyer. The quantity given 
 refers to the percentage in solution. 
 
 ■ci v' i j v 1,10 m jj ( acState of alumina . . 15.8 
 
 English red liquor — 14° Twadd. < , t . « . ^ 
 
 G ^ ( sulphate of potash . . 8 
 
 16.1 
 
 q . i tsj -.o-io m aa f acetate of alumina . . 11.5 
 Scotch, No. 1 — 161° Twadd. < , , . „ ' , ' 
 ' A [ sulphate oi potash . . 2.6 
 
 13.8 
 
 acetate of alumina . . 14. 
 
 1.2 
 
 c j. i. at o i /( o m aa ( acetate of alumina 
 
 Scotch, No. 2 — 14° Twadd. < , , . Q . , 
 ' ( sulphate or potash 
 
 l ■ 
 
 Scotch, No. 3—15° Twadd 
 
 15.2 
 
 acetate of alumina . . 12.2 
 sulphate of potash . . 2.6 
 
 14.8 
 
 We have given these varieties to show how little reliance 
 ought to be placed on the indications of the hydrometer. No. 
 10 
 
146 
 
 ALUM MORDANTS. 
 
 3 is of a higher specific gravity than the English red liquor, 
 but far inferior as a mordant. Again, such a mordant as No. 
 1 has a tendency to make light spots upon goods dyed green 
 by fustic or bark, the alumina being the effective agent in the 
 red liquor. The above is an ample illustration of the necessity 
 of some better mode of testing than at present in use. 
 
 During the various applications of these aluminous mordants, 
 and the manipulations attending them, many curious and inter- 
 esting chemical phenomena are witnessed by the dyer, although 
 his familiarity with them often prevents any particular remark ; 
 we shall instance one or two of those attendant upon the pro- 
 cess of dyeing madder reds, by means of acetate of alumina. 
 This process, however, is more immediately connected with 
 calico printing, while our particular object in this work is dye- 
 ing yarns and cloth to be finished as such. The cloth to be 
 dyed is first thoroughly bleached and dried; it is then padded 
 or soaked in acetate of alumina, about the specific gravity of 
 40° (8 Twaddell), and passed at full breadth through nipping 
 rollers (squeezers). These are large rollers covered with cloth, 
 which revolve one upon another. The pressure upon the 
 piece, as it passes through for the purpose we are describing, 
 ought to be such that it will dry in five minutes, passing over 
 rollers in a stove heated to 160° Fah. Pieces mordanted with 
 acetate of alumina, and dried at a great heat, are highly 
 charged with electricity. If the hand be suddenly drawn along 
 the piece, a complete shower of fire is observed, with a sharp 
 crackling noise, at the same time a prickling sensation is felt. 
 Whether this has any effect upon the mordant, in its imme- 
 diately combining with other substances, we do not know ; but 
 cloth in this state is very ill to moisten; water runs off it as 
 off* a duck's wing, but as yet we offer no explanation. After 
 being dried, the goods are passed through a dung bath, made 
 up with about one part cow's dung to fifty parts water, at a heat 
 of 130° Fahrenheit; from this, they are well washed through 
 the dash-wheel. Into a boiler of cold water is put from one 
 to three pounds of madder, according to the color wanted, for 
 every pound of cloth. The cloth is put in, and a fire is kindled 
 under the boiler, and so regulated that it will boil in two hours, 
 during which the cloth is kept running over a winch, or wheel, 
 first in one direction and then the other, and kept spread as 
 much as possible, so that the whole surface may be equally 
 exposed to the dyeing operation. The boiler is kept at the 
 boil from twenty to thirty minutes; this, with washing first 
 through bran, and then water, completes the dyeing operation. 
 If a white pattern be wanted upon these reds, the pattern is 
 printed upon the goods with citric acid (about 25° of Twaddell, 
 
ALUM MORDANTS. 
 
 147 
 
 thickened with pipe-clay and gum), about twelve or twenty 
 four hours after being dried from the mordant. This decom- 
 poses the aluminous mordant upon these parts, so that no dye 
 adheres to them afterwards. It is of the utmost consequence 
 that the goods be thoroughly cooled previous to printing on the 
 resist, otherwise there is danger of its not being successful. 
 
 Now, from a difference in the manipulation, or a little varia- 
 tion upon some of these processes, several curious changes take 
 place upon the mordant. For example, were the pieces merely 
 washed with water from the mordant, previous to printing on 
 the resist acid, although the treatment be every way else the 
 same, v the discharge of the mordant is not effected ; those parts 
 upon which the citric acid is printed will be scarcely observa- 
 ble after the cloth is dyed, while in the other case they are per- 
 fectly white. 
 
 A somewhat similar result, in reference to the action of the 
 discharge acid, takes place, if the heat of the stove in which 
 the goods are dried from the mordant exceeds a certain tem- 
 perature, or if dried upon steam rollers.* No acid, printed 
 upon the cloth after this, will produce a white, except it be of 
 a strength that will destroy the fabric of the goods ; besides 
 this, the colors afterwards dyed upon mordants heated in this 
 manner are extremely bad, being heavy and dull. 
 
 Various opinions have been offered by practical men upon 
 the probable cause of these changes. Some suppose that, by 
 the excess of heat, the acetate of alumina is altogether decom- 
 posed, the acetic acid flying off, and the alumina left in the 
 goods adhering with such an affinity that it requires a stronger 
 Hcid than the cloth will bear to disengage it; but from the 
 similarity of the effects which take place, by merely washing 
 the piece from the mordant, this opinion is liable to objection, 
 lor the subacetate of alumina is not decomposed by washing 
 with water; however, different causes may produce the same 
 effects. If this opinion be correct, the circumstance of a bad 
 color resulting from the acetate being decomposed, will be a 
 proof that it is not the alumina alone which constitutes a mor- 
 dant, but its salt ; in this case, it is the subacetate of alumina — 
 the acetic acid being an essential ingredient to the dyeing pro- 
 cess. This we are inclined to believe, for in those mordants, 
 as we have already stated, where the acid can be separated by 
 washing, the proper color is not produced until some salt or 
 acid be added to the coloring matter as an alterant. It is sup- 
 posed by some writers that the dunging and washing extract 
 
 * Large metal cylinders into which steam is admitted, and the cloth 
 passed over the surface. 
 
148 
 
 SALTS OF ALUMINA. 
 
 the acid from the mordant, and leave the base upon the cloth. 
 This we conceive to be an error ; for although the part which 
 dung acts in these processes is not well understood, yet from 
 the analysis of this substance, and the nature of the saltswhich 
 are supposed to be useful in these operations, there is no proba- 
 bility of the aluminous salt being decomposed. One principal 
 use of the dung bath is to combine with and carry off any 
 loose or supernatant mordant which may be upon the cloth, 
 not combined, and which might affect the color, or more par- 
 ticularly the parts wanted to be white. 
 
 Alumina combines with all the acids, forming salts similar 
 to those already described, and all difficult to crystallize, ex- 
 cept as double salts, such as alum, which they form with other 
 salts beside those named ; but none of the others have been 
 introduced into the dye-house. 
 
 Alumina, as an earth, is of great value in many other arts, 
 as in pottery, brickmaking, &c. It also forms the bases of some 
 of the finest precious stones; the sapphire and ruby, for exam- 
 ple, are nearly pure alumina. 
 
 The salts of alumina, such as alum, act towards other salts 
 and reagents, as under: — 
 
 Potash White precipitate, which is redissolved 
 
 in an excess of the precipitant. 
 
 Ammonia .... White precipitate, insoluble in an ex- 
 cess of the precipitant. 
 
 Carbonate of potash . White precipitate, not soluble in an 
 
 excess of the precipitant, but soluble 
 in caustic potash. 
 
 Caustic soda and its carbonate act in the same way as caustic 
 potash and its carbonate. 
 
 Carbonate of ammonia and phosphate of soda act in the same 
 way as carbonate of potash. 
 
 All these precipitates are soluble in acids. 
 
 Oxalic acid ...... No precipitate. 
 
 Yellow prussiate of potash . Precipitate, after standing for 
 
 some time. 
 
 Eed prussiate of potash . . No precipitate. 
 
 All these precipitates of alumina have a bulky and a kind of 
 plastic appearance, easily recognized and distinguished. 
 
 When a substance containing alumina is heated to redness, 
 especially before the blowpipe, and is touched with a solution 
 of nitrate of cobalt, and then again heated, it takes a beautiful 
 blue color. In this way a very small portion of alumina may 
 be detected in any solid substance; but when the substance 
 
MANGANESE. 
 
 149 
 
 is in solution, it must be detected by the reaction of some of 
 the reagents given above. It may also be noticed, that when 
 operating to obtain a precipitate, it is necessary to be careful 
 that only pure water is used for washing the precipitate. If 
 the water is not pure, the precipitate will attract the impurity, 
 especially if it consists of any organic matters, and thus be- 
 come tinged, and assume an appearance as if iron were present. 
 
 The next general division of chemical elements consists of 
 the Metals Proper. These are very numerous, but a great 
 many of them are so rare as to have been seen by a very few 
 chemists, and are only obtained in particular localities; con- 
 sequently, their properties have not been much investigated, 
 and no practical applications have been made of them. Of these, 
 a very short description will suffice, so that our remarks may 
 be more extended upon those which have a known practical 
 value. The first of which is 
 
 Manganese (Mn 27.6). 
 
 This metal is not found in nature in a separate state, but 
 exists abundantly in combination with oxygen. From this cir- 
 cumstance it was long considered a species of earth like mag- 
 nesia, and was consequently called magnesia nigra ; but it was 
 discovered to be the oxide of a metal in 1774, by Scheele and 
 Gahn, and was then named manganese. 
 
 As a metal, it has a grayish-white lustre, resembling cast- 
 iron; it is very difficult to fuse, and it combines with oxygen 
 so quickly that it cannot be kept in the open air. It passes 
 into several states of oxidation. The one in which it generally 
 exists in nature is the peroxide having 2 proportions of oxygen 
 to 1 of metal = Mn 0 2 . When this oxide is heated at a low 
 red heat, it loses a part of its oxygen, and passes into the state 
 of sesquioxide = Mn 2 0 3 . When heated to bright redness, it 
 loses more oxygen, and becomes what is termed red oxide, or 
 a mixture of the protoxide Mn 0 and of the sesquioxide Mn 2 
 0 3 . The peroxide does not unite with either acids or alkalies. 
 When boiled with sulphuric acid, one proportion of the oxygen 
 is evolved, and the protoxide Mn 0 unites with the acid, and 
 forms sulphate of manganese, which is used in dyeing. 
 
 Peroxide, or black j° Oxygen gas. 
 
 oxide of manganese 
 
 Sulphuric acid. 
 
 Water. 
 
 Sulphate of manganese. 
 
150 
 
 MIXER A L CAME LEON. 
 
 When the peroxide is digested in hydrochloric acid, chlo- 
 rine is evolved, and chloride of manganese formed. This is 
 often done in houses for the purpose of fumigation. The re- 
 action is thus expressed : — 
 
 hydrochloric acid 
 
 [ CI.. Chlorine gas. 
 
 Two proportions of j CI.. 
 
 H.. 
 H.. 
 
 0.. Water. 
 Binoxide of manganese •< O .. y* Water. 
 
 (Mn X Chloride of manganese. 
 
 The oxide of manganese is extensively used in the manu- 
 facture of bleaching powder, for obtaining the chlorine from 
 common salt. (See page 79.) 
 
 Manganese combines with almost all the acids forming salts, 
 which in their crystallized or dry state have less or more of a 
 pinky hue. In making these salts from the peroxide, there is 
 always oxygen liberated ; they are therefore all what are termed 
 salts of the protoxide. But by removing the acid, the protox- 
 ide soon combines with more oxygen, and becomes brown. It 
 is this circumstance that has made it applicable in dyeing. In 
 preparing any of the salts of manganese for dyeing purposes, 
 care should be taken that the salt be free from iron, as that metal 
 is deleterious. The sulphate of manganese may be free from 
 iron by exposing it to a red heat, then dissolving the residue 
 in water. By this means the iron present is peroxidized ; it is 
 thus rendered insoluble, and consequently sinks to the bottom. 
 
 When cotton is passed through a solution of sulphate of 
 manganese, and then through a weak solution of an alkali, the 
 manganese oxide is left within the fibre, and by exposure be- 
 comes brown by attracting more oxygen. Or if the cloth be 
 immediately passed through a solution of weak bleaching liquor, 
 the protoxide is converted into peroxide without exposure. 
 This is the method generally adopted ; it gives a brown, which 
 is very dull and heavy, but also very permanent. 
 
 Mineral Cameleon. — When peroxide of manganese is fused 
 with carbonate or caustic potash, there is formed what has been 
 long known as the mineral cameleon. When this is first put into 
 water, it produces a deep green solution, but passes rapidly to 
 a red by absorbing oxygen. This compound is not used in 
 dyeing, but we think it contains properties worthy of exami- 
 nation. It illustrates very forcibly the effects of oxygen in 
 changing the colors of substances, and the rapidity with which 
 these changes take place ; accordingly teaching the necessity of 
 attending to every condition, no matter how apparently trifling, 
 
IRON. 
 
 151 
 
 as often the merest trifle* may be of the greatest consequence 
 in a process. 
 
 The salts of manganese, in solution, are affected by the fol- 
 lowing reagents. — 
 
 Potash Brown precipitate. 
 
 Soda and ammonia Brown precipitate. 
 
 Carbonates of potash and soda . Brown precipitate. 
 Yellow prussiate of potash . . Dirty-green precipitate. 
 Eed prussiate of potash . . . Brown precipitate. 
 
 Manganese is easily detected by this general property of 
 turning brown when exposed, and giving a brown with all the 
 alkaline reagents. 
 
 Iron (Fe 28). 
 
 This is one of the most useful, generally diffused, and abun- 
 dant of the metals. There is almost no substance, whether 
 organic or inorganic, quite free from iron. Its uses in the 
 various arts and purposes of life are innumerable. The most 
 common iron ores of this country are the clay iron-stones, of 
 which there are several varieties, and in which the iron exists 
 as a carbonate along with silica, alumina, carbon, and a little 
 sulphur. The ore is first calcined at a red heat, which expels 
 the carbonic acid and sulphur ; it is then mixed up with lime- 
 stone and coal, and put into a blast-furnace, and subjected to 
 intense heat, the effect of which is, that the silica and alumina 
 combine with the lime, and form a glass ; the coal takes the 
 oxygen from the iron, and passes off with it as carbonic acid ; 
 the metal meantime fuses, and in consequence of its superior 
 gravity, sinks to the bottom of the furnace, while the glass 
 and scorise float above it, and are run off separately when the 
 furnace is tapped. 
 
 Iron combines with oxygen in two proportions : — 
 
 Protoxide of iron Fe O. 
 
 Peroxide of iron ... . . . Fe 2 0 3 . 
 
 Both of these oxides unite with acids, and form with them 
 two classes of salts, distinguished from each other by affixing 
 pro and per to their names. Both salts are extensively used 
 in the dye-house. 
 
 M. Fremy gives the following statement of what he called a 
 third oxide of iron, which he had obtained in combination : — 
 
 "This oxide is obtained by igniting a mixture of potash and 
 peroxide of iron; a brown mass is the result, which, by diges- 
 
152 
 
 SULPHATE OF IRON. 
 
 tion in water, gives a beautiful violet-red colored solution. The 
 compound is very soluble in water. A large quantity of water 
 decomposes it in course of time. But it becomes insoluble in 
 very alkaline water, forming a brown precipitate, which readily 
 dissolves in pure water, and affords a fine purple-colored solu- 
 tion. A temperature of 212° dissolves it immediately ; all 
 organic substances decompose it; and hence it is impossible to 
 filter the solution. It is impossible to isolate this compound, 
 for when the red solution is treated by an acid, as soon as the 
 potash is saturated, oxygen is disengaged, and peroxide of iron 
 precipitated. If the acid be in excess, it dissolves the peroxide, 
 and gives rise to the formation of a persalt of iron. It is stated 
 to possess a powerful dyeing principle." 
 
 Protoxide of iron is very difficult to be obtained in an iso- 
 lated state, on account of its great affinity for oxygen, which 
 causes it to pass into the state of peroxide very rapidly. When 
 an alkali is added to a protosalt of iron, the protoxide is pre- 
 cipitated as a hydrate of a gray color, which, by exposure to 
 the air, soon becomes peroxide of an ochrey-red color, as is 
 seen almost daily in the dye-house during the dyeing of nan- 
 keen or buffs by a protosalt of iron or copperas. 
 
 The goods are dipped into the sulphate of iron solution, and 
 then passed through lime-water; the lime combines with the 
 acid, and leaves the hydrated protoxide precipitated within or 
 upon the fibre; the shade is then greenish, but a slight expo- 
 sure peroxidizes the iron, and produces the nankeen or buff. 
 This property of the protoxide of iron, of passing into the per- 
 oxide by its strong attraction for more oxygen, is beautifully 
 applied in some of the operations of dyeing besides the one 
 referred to, and which will be more fully described when treat- 
 ing of the blue vat. 
 
 Sulphate of Iron {green vitriol, or copperas). — This salt is 
 very easily prepared, merely by adding metallic iron to sul- 
 phuric acid, which has been diluted by 3 or 4 parts of water. 
 The iron quickly dissolves, with rapid evolution of hydrogen 
 gas. The reaction taking place may be thus represented : — 
 
 When as much iron is dissolved as the acid will take, the solu- 
 tion is evaporated by heat, until a pellicle or thin skin appears 
 on the surface. It is then set aside in a cool place, and in a 
 short time there is formed a quantity of green-colored crystals 
 of sulphate of iron. These crystals contain 7 proportions of 
 water of crystallization, or in iOO parts 
 
 Sulphuric acL 
 Iron 
 
 Fe.. 
 
 Sulphate of iron. 
 
 Hydrogen gas. 
 
SULPHATE OF IRON". 
 
 153 
 
 Sulphate of iron, Fe S0 4 54.5 
 
 Water 45.5 
 
 100.0 
 
 If these crystals are heated a little above the boiling point 
 of water to 238° Fah., they part with all this water except one 
 proportion, or about 10 per cent. The salt also loses its green 
 color, and becomes white. The crystals of sulphate of iron 
 require the following quantities of water to dissolve them: — 
 
 1 
 
 gallon water at 
 
 50° 
 
 Fah. dissol 
 
 ves 6 lbs. 
 
 cr 
 
 1 
 
 • (i 
 
 59° 
 
 ci 
 
 7 
 
 t< 
 
 1 
 
 it 
 
 75° 
 
 a 
 
 HI 
 
 u 
 
 1 
 
 ii 
 
 109° 
 
 a 
 
 15 
 
 u 
 
 1 
 
 a 
 
 115° 
 
 tt 
 
 22f 
 
 u 
 
 1 
 
 it 
 
 140° 
 
 a 
 
 261 
 
 a 
 
 1 
 
 ii 
 
 183° 
 
 u 
 
 27 
 
 a 
 
 1 
 
 ti 
 
 194° 
 
 tt 
 
 37 
 
 a 
 
 1 
 
 ci 
 
 212° 
 
 tc 
 
 33| 
 
 
 This table, which is of a similar character to tables of many 
 other substances dissolving at a certain temperature, is inte- 
 resting, and accounts for many of the circumstances occasion- 
 ally observed in the dye-house — that sometimes the same stuff 
 seems much more difficult to dissolve than at other times. Tt 
 also shows why crystallization may occur much more rapidly 
 at one time than at another. If we note the increase of heat 
 and solubility, we shall see how irregular they are: — 
 
 1st, an increase of 
 
 9° 
 
 dissolves 1 lb. 
 
 more than at 
 
 50° 
 
 2 
 
 16° 
 
 " 41 
 
 ii 
 
 59° 
 
 3 
 
 34° 
 
 " H 
 
 tt 
 
 75° 
 
 4 « 
 
 6° 
 
 " 7| 
 
 a 
 
 109° 
 
 5 " 
 
 25° 
 
 " 3J 
 
 t< 
 
 115° 
 
 6 " 
 
 43° 
 
 " 0| 
 
 u 
 
 140° 
 
 7 
 
 11° 
 
 " 10 
 
 ii 
 
 183° 
 
 8 « 
 
 18° 
 
 " 34 
 
 less than 
 
 194° 
 
 Ten gallons water, at 194°, will dissolve 100 lbs. more cop- 
 peras than the same quantity of water only 11° colder; a fact 
 quite sufficient to account for many of the phenomena which 
 exist in the practical operations of the dye-house. 
 . The sulphate of iron of commerce is not made by dissolving 
 metallic iron in acid, which would be too expensive a process, 
 but from the sulphureted ores of iron (iron pyrites).* 
 
 * Large quantities of copperas are produced by dissolving scrap iron in 
 refuse sulphuric acid from alum, petroleum, and oil works. 
 
154 
 
 SULPHATE OF IRON. 
 
 We have already, in treating of alum, given an account of 
 the manufacture of a great quantity of the copperas of com- 
 merce; but there are numerous and extensive places for manu- 
 facturing this salt alone, where no alum is made. The opera- 
 tions are, however, nearly the same as those described for 
 alum. 
 
 Iron pyrites is a bisulphuret of iron, Fe S 2 ; in 100 parts it 
 has 52 of sulphur and 48 of iron. This compound, when 
 obtained from the older geological formations, undergoes spon- 
 taneous decomposition by exposure to the air and moisture ; 
 the sulphur combines with the oxygen of the air, and forms 
 sulphurous acid, which again, in the presence of water and 
 oxide of iron, takes more oxygen, and becomes sulphuric acid, 
 which in turn combines with the iron. Generally, these pyrites 
 are made into large heaps and set on fire, in the same manner 
 as the alum-shale is treated in the preparatory process of the 
 alum manufacture. This roasting causes the rapid oxidation 
 of the sulphur, and consequent formation of the sulphate of 
 iron, which is all dissolved out, by passing water through the 
 heaps and collecting it into tanks. Owing to the excess of 
 sulphur over the iron, there is generally in the solution an ex- 
 cess of acid, with, also, some persalt of iron, and often small 
 quantities of copper, which would be deleterious. To get rid 
 of this, a quantity of old iron is put into the solution, which 
 takes up the excess of acid at the same time that it precipitates 
 the copper from the solution. Thus, 
 
 Old iron Fe Sulphate of iron. 
 
 It reduces all the persulphate of iron to the state of protosul- 
 phate: Thus, 
 
 The solution is then evaporated to a proper density and crys- 
 tallized. This method of adding old iron to produce the 
 changes described, not being in all cases adopted, gives rise to 
 some of the varieties of copperas found in the markets, concern- 
 ing which there is much prejudice in the minds of dyers. 
 
 M. Dumas ascribes the variations to the formation of a 
 double salt of the proto and per sulphate, during the decompo- 
 sition of the pyrites. M. BansdorfF [Records of General Science) 
 
 Sulphate of copper 
 
 Persulphate of iron { S0 4 
 
 Old iron 
 
SULPHATE OF 1KOX. 
 
 155 
 
 states, that there are three varieties of the protosulphate of iron ; 
 the first greenish-blue, formed from an acid solution free from 
 peroxide; the second, dirty-green, from a neutral solution with- 
 out peroxide; and the last, emerald-green, from a solution im- 
 pregnated with peroxide salt. This we know is consistent 
 with experience — that answering the description of his second 
 variety being the best for general use ; but the selection of this 
 particular quality of copperas has led dyers into a fatal preju- 
 dice. Sulphate of iron crystallized from a neutral solution, if 
 kept any time, assumes a rusty appearance by absorbing oxygen, 
 and forming a film of peroxide of iron. Now, good copperas 
 having generally this appearance, especially on the surface of 
 the cask w r hen opened, dyers pretty generally entertain the 
 opinion that it is to this redness it owes its superior quality. 
 This, we need hardly say, is an erroneous opinion, concerning 
 which, Mr. Parks mentions, in his Chemical Essays, that some 
 unprincipled dealers take the advantage to sprinkle lime on the 
 top of the cask to peroxidize the surface, and make the dyers 
 believe that they have got a lot of excellent old copperas. 
 
 As copperas is generally judged of by the color, the worst 
 colored copperas has sometimes a solution of common salt or 
 of lime sprinkled upon it to give it a dark tint; but although 
 this may deceive the eye, it does not improve its bad qualities. 
 
 Copperas, crystallized from solutions of sulphate of alumina, 
 will also have an acid reaction when used for some of the pur- 
 poses of the dye-house, such as the blue vat, and may be the 
 origin of the light-green colored copperas, by giving much more 
 water of crystallization than the other. The difference of value 
 between the light green watery-colored crystal and the dark- 
 green, is, by experience, about 14 per cent, in favor of the latter. 
 The effects of this will be noticed more fully under the blue vat. 
 But these results we believe to be the reason why a practical 
 dyer, in an excellent treatise upon his trade, states that there is 
 a bisulphate of iron, and warns the trade against its use.* 
 
 As this watery-looking bluish-green copperas, according to 
 Bansdorff, crystallizes from an acid solution, it is probable that 
 the extra proportion of acid which is found in it, is owing to a 
 portion of mother-liquor being mechanically combined with 
 the crystals, but not forming an essential ingredient in the com- 
 position of the salt. And if the salt has been crystallized from 
 sulphate of alumina, the excess of acid will be more apparent. 
 
 The result of experience upon the relative value of the light- 
 green watery-colored copperas over the dark-green, or what are 
 generally termed new and old, is as 21 to 24, or 100 lbs. of best 
 
 * Cooper's Treatise on Practical Dyeing. 
 
156 
 
 SULPHATE OF IRON. 
 
 old copperas is worth 114 lbs. of new light-green. In testing, 
 there is always an excess of acid, but not in quantity anything 
 like this difference. As the color of the crystals of sulphate of 
 iron depends upon the presence of water, may it not therefore 
 be inferred that the difference of color depends upon the pro- 
 portion of water present in the crystals, which, if this be the 
 case, will account for the different proportions of iron which we 
 have often found in the same weight of the salt. It has been 
 already noticed, that of the seven proportions of water which 
 copperas contains, it loses six at 238°. We took 20 grains of 
 each of the good and bad qualities of copperas, reduced them to 
 coarse powder, and submitted them to a heat of between 305° 
 to 400°, and taking the mean of several experiments, the bad 
 copperas lost 1J grains more than the other, or 1\ per cent., 
 a result which agrees with the experience of the dyer. It being 
 well known that copperas, being exposed to the air in a dry 
 place, loses water. 
 
 English copperas is considered superior to Scotch. The 
 former is mostly made from pyrites, while the latter is made 
 from alum shale, and is therefore very liable to contain small 
 portions of sulphate of alumina; and, being crystallized from a 
 strong solution of the sulphate of a salt of another metal, has 
 every chance of being inferior. 
 
 The presence of alumina may be detected by dissolving 
 some of the salt in water, and boiling the solution, during 
 which a few drops of nitric acid are added to peroxidize the 
 iron, which is known by the solution becoming a clear amber 
 color. Caustic potash is then added in considerable excess, 
 until the solution is alkaline, and the whole is then boiled 
 for some time and passed through a filter upon which the 
 peroxide of iron is retained. The solution contains the alumina. 
 The potash is neutralized by sulphuric acid, and on adding 
 ammonia to this solution, if alumina be present, a flocculent 
 white precipitate is obtained. Other tests for alumina are 
 given under that element. If ammonia be added to the iron 
 precipitate retained upon the filter, the solution passing 
 through will become blue, if copper be present. It is best to 
 test for the presence of copper separately ; this is done by 
 dissolving the copperas, as described, peroxidizing with acid, 
 adding ammonia instead of potash, and filtering; the slightest 
 trace of copper will tinge the solution blue. Or it may be 
 detected by dissolving a little of the crystals, and putting 
 into the solution a piece of clean polished iron, such as the 
 blade of a knife; when, if any copper be present, it will be 
 precipitated upon the iron in a metallic state. The presence 
 of zinc may be detected in copperas by taking the ammoniacal 
 
ACETATE OF IRON. 
 
 157 
 
 solution which has passed through the iron in testing for 
 copper, and, if no copper be present, pass a stream of the sul- 
 phuretted hydrogen gas through the solution ; the zinc, if there 
 be any present, will give a white precipitate. This metal is, 
 however, very seldom found in copperas. The effects of the 
 presence of these salts, in some of the operations where cop- 
 peras is used, will be considered when treating of the blue vat. 
 Magnesia is occasionally found in copperas, but its reactions 
 are not deleterious. 
 
 Chloride of Iron. — Iron is easily dissolved in hydrochloric 
 acid when treated in the same way as was described for dis- 
 solving the metal in sulphuric acid, and the product is chloride 
 of iron. 
 
 Hydrochloric acid | j^jj ^ drogen gas. 
 
 Iron Fe ^ - Chloride of iron. 
 
 This salt crystallizes in green-colored crystals, but with diffi- 
 culty. The crystals are very soluble in water, and pass rapidly 
 into the perstate. For some purposes in dyeing, this salt could 
 be used equally with copperas, but for others, such as the blue 
 vat, it would not do so well. Moreover, the expense of making 
 it precludes its extensive use in the arts. 
 
 Carbonate of Iron. — This salt, as we have already said, 
 exists as an ore ; but it is easily prepared, by adding to a solu- 
 tion of copperas, a solution of carbonate of potash or soda. It 
 is a whitish green colored precipitate, and is obtained by 
 double decomposition. 
 
 Carbonate of potash |g- ^\mLIT^ 
 
 Sulphate of iron . . \ ^ 4 ~ , , * . 
 
 1 (Fe.. -^-Carbonate of iron 
 
 (precipitate). 
 
 This precipitate cannot be dried in the air without losing its 
 carbonic acid, and passing into the state of peroxide; but it 
 is soluble in water impregnated with carbonic acid. This is 
 the state in which iron is generally held in solution in spring 
 waters. 
 
 Acetate of Iron. — Acetic acid, or vinegar, acts readily 
 upon iron, dissolving it, and forming the acetate, which crys- 
 tallizes in small green crystals, very rapidly acted upon by the 
 air. This salt is much used in dyeing in the liquid state; it 
 is known as iron liquor, and pyrolignite of iron, from its being 
 prepared on the large scale with crude wood vinegar. The 
 acetate of iron may be prepared by mixing together acetate of 
 lead and protosulphate of iron. The sulphate of lead is formed 
 
158 
 
 NITRATE OF IRON. 
 
 and falls to the bottom ; the acetate of iron remains in solu- 
 tion. The pyrolignite of iron is in general preferable. It is 
 prepared by allowing iron to steep in pyroligneous acid (im- 
 pure acetic acid) for several weeks. As this acid contains a 
 quantity of pyrogenous oils and other impurities, it preserves 
 the iron for a longer time in a state of protoxide than almost 
 any other solvent available in the arts; hence the decided 
 preference given to it by practical men. We shall often have 
 occasion to refer to this subject, as it is one which is too much 
 neglected, and which produces many serious evils. It may, 
 however, be in the meantime observed, that pyrolignite of 
 iron, used instead of copperas in dyeing black, gives a prefer- 
 able shade of color. 
 
 The value of this solution may be taken by evaporating a 
 known weight to dryness, and burning the residue until all 
 organic matters are consumed, when there remains only the 
 iron as a peroxide : every forty grains of the peroxide will be 
 equal to ninety-six of the acetate of iron in the solution. The 
 operation is very simple, and the percentage of acetate of iron 
 in the solution known. The average of good iron liquor ranges 
 about 13.5 per cent, of pure protoacetate of iron, the specific 
 gravity being about 1.085 = 17° Twaddell. The state of 
 oxidation in which a metal exists, when used as a mordant, 
 ought to be strictly attended to. 
 
 Iron combines in the protostate with oxalic acid, tartaric 
 acid, and, indeed, with all the acids, but these salts possess no 
 peculiar advantages over those before described to warrant any 
 extra expense in preparing them. 
 
 Persulphate of Iron. — Persalts of iron are also exten- 
 sively used in the dye-house. The persulphate of iron may 
 be easily prepared by boiling a solution of copperas, to which 
 a few drops of sulphuric acid have been added, and, while 
 boiling, adding a very small portion of nitric acid, or any ni- 
 trate ; red fumes are given off, and the solution becomes of a 
 beautiful amber color. It is then in the state of a persalt. 
 Chlorate of potash may be used instead of nitric acid or nitrates. 
 The persulphate of iron might be advantageously used for 
 many operations, and be cheaper than the nitrate of iron. 
 
 Nitrate of Iron. — This is the persalt of iron generally 
 used in the dye-house. It is made by putting clean iron into 
 nitric acid, by which it is very quickly dissolved. The iron 
 ought to be added as long as the acid continues to dissolve it; 
 but cautiously, otherwise the action will be so violent as to 
 cause it to boil over. When engaged in this process, care 
 ought to be taken not to breathe any of the fumes which come 
 off, as they are very destructive to health. The. reaction which 
 
NITRATE OF IRON. 
 
 159 
 
 takes place between the acid and the iron may be expressed 
 as in the table below — which we introduce by remarking that, 
 in dissolving iron in sulphuric or hydrochloric acid, there is 
 merely a substitution of the iron for the hydrogen (see p. 45); 
 but with nitric acid a different range of affinities takes place: 
 the elements of the acid are not held together so powerfully as 
 those of sulphuric acid ; so that one proportion of the nitric 
 acid is broken up, producing the following arrangement: — 
 
 The binoxide of nitrogen is the gas passing off; but it in- 
 stantly combines with more oxygen, and forms peroxide of 
 nitrogen. 
 
 The nitrate of iron alone dyes a buff or nankeen color, 
 which is probably the easiest dyed of any of the colors, and is, 
 at the same time, very permanent. The process only requires 
 that a little of this salt be put into water, and that the goods 
 be immersed in the solution for a few minutes, then washed in 
 clean water and dried. Passing them through a weak soap 
 solution softens the goods, and gives clearness to the tint. 
 But the particular use of this salt is for Prussian blue. The 
 goods are first dyed buff' by the salt of iron, then thoroughly 
 washed and put into a very dilute solution of ferroprussiate of 
 potash, made acid by a few drops of sulphuric acid ; they are 
 washed from this in clean water, to which a little alum has 
 been added. (This is only for light blues on cloth ; but for 
 dark blues, and for yarn, the proper methods will be given 
 hereafter.) We have known many attempts made to substitute 
 copperas for nitrate of iron in dyeing Prussian blue, but need 
 hardly say they were unsuccessful. A very little knowledge 
 of the nature of these salts would have told the experimenters 
 that protosalts of iron give only a grayish color with yellow 
 prussiate of potash; but, with red prussiate of potash, copperas 
 is a better mordant than nitrate of iron, as the red prussiate 
 gives a dark blue with the protosalts, and only a greenish 
 gray with the persalts of iron. 
 
 N.. 
 O.. 
 
 Binoxide of nitrogen. 
 
 One nitric acid 
 
 Three proportions 
 
 nitric acid 
 
 Two proportions of iron 
 
160 
 
 NITRATE OF IRON. 
 
 The preparation of nitrate of iron (killing iron) is apparently- 
 one of the most simple operations of the dye-house, as all that 
 is required is to place metallic iron into nitric acid; but the 
 practical dyer often experiences difficulties which he cannot 
 account for, and which alter materially his shades and colors. 
 Sometimes, as we have already noticed, the iron seems not to be 
 acted upon; at another time the action is so rapid that there 
 is a difficulty in preventing the liquid boiling over. When 
 the acid is a little diluted, and the iron is added in small pieces, 
 the action is violent, and there is formed a brown turbid 
 clay-looking solution. Colors dyed by the iron in this state 
 are never brilliant. We have seen solutions of this sort di- 
 luted largely with water, the brown mass allowed to settle, 
 and the clear only used, but this is tedious, and not good after 
 all. The best means of improving this mordant is to remove 
 all metallic iron, add a little nitric acid, and apply heat. 
 
 When the nitric acid is not diluted, and the iron dissolves 
 freely, and when the acid is saturated with iron, if the remain- 
 ing metallic iron is not removed, it continues to dissolve by 
 the reaction of the nitrate of iron upon it thus: — 
 
 Protonitrate. 
 ^Protonitrate. 
 
 One part nitrate of iron 
 
 One part iron .... Fe Protonitrate. 
 
 This protonitrate rapidly imbibes oxygen, passes into the per- 
 nitrate, and, in so doing, liberates a portion of oxide of iron, 
 which collects at the bottom of the vessel, and accumulates so 
 rapidly that the iron solution is soon converted into a brown 
 paste. This can be avoided by taking out the iron when the 
 acid is saturated, and before this deposit begins. The addition 
 of a little acid and heat redissolves this oxide; or a little sulphu- 
 ric or hydrochloric acid also dissolves it, and with it forms an 
 excellent mordant. 
 
 A still more remarkable circumstance often occurs: the iron 
 being placed in the acid, and action going on favorably, after 
 a few hours, particularly if the weather be cold, the solution is 
 observed to have a greenish-yellow color, and the vessel is 
 found to be half filled with crystals of a light yellow tint. 
 Although these crystals when dissolved in water, or the solu- 
 tion above the crystals, may be used for dyeing, they give 
 varieties of quality from the usual iron solution, which often 
 seriously destroy the method of the dye-house. The true 
 nature of the crystals is not well understood, and it is difficult 
 
PROTOSALTS. . , 161 
 
 to get at their examination, as they are very deliquescent, dis- 
 solve easily in water, and even in their own water of crystal- 
 lization, by a slight elevation of temperature above summer 
 heat. When put upon blotting-paper they are decomposed, 
 and the paper imbibes much of the iron. We long thought 
 that they were caused by the formation of ammonia in dissolv- 
 ing the iron, but experiments have failed to show the slightest 
 trace of ammonia. The analysis of these crystals, by J. M. 
 Ordway, gave 3 nitric acid, 1 peroxide iron, and 18 water =3 
 N0 5 + Fe 2 0 3 + 18 HO. The same author has examined nitrates 
 of iron of different qualities, and states that nitric acid combines 
 definitely with various proportions of peroxide of iron and 
 water, forming what he terms basic nitrates, varying from 3 
 acid, and 1 peroxide iron, to 3 acid, and 2, 3, 6, 8, 12, 15, 18, and 
 24 peroxide of iron, w T ith various definite quantities of water, 
 giving an interest to this salt of the highest sort, and amply 
 accounting for the great difference experienced in its use for 
 dyeing ; and also for the ease with which peroxide of iron is 
 fixed upon the fabric when put into this salt ; the basic salt 
 being decomposed, and a portion of the oxide of iron left upon 
 or within the fibre. There are many other phenomena ob- 
 served in working with these salts, which we shall yet have 
 occasion to notice. 
 
 Any other persalt of iron may be formed by adding ammo- 
 nia, soda, or potash to the nitrate of iron solution, so long as a 
 precipitate is formed, washing the precipitate, by repeatedly 
 filling the vessel which contains it with water, allowing it to 
 settle, and decanting off the clear, then adding to the precipi- 
 tate the acid of which the salt is wanted. The application of 
 heat assists the solution of the precipitate in the acid. By these 
 means peracetate, peroxalate, pertartrate, &c, may be obtained 
 either for practical use or experiments. 
 
 The following is the reaction of different substances upon 
 the pro and per salts of iron. 
 
 Protosalts. — Potash, soda, and ammonia give at first a 
 gray-white precipitate, passing into green, then bluish, and 
 which by exposure, finally becomes brown. 
 
 Carbonates of these alkalies produce precipitates, which pass 
 through the same changes as the alkalies themselves. 
 
 Yellow prussiate of potash . A gray-white precipitate, which, 
 
 by exposure, becomes blue. 
 
 Eed prussiate of potash . . An immediate dark-blue precipi- 
 tate. 
 
 Solution of galls A blue-black, not changed by 
 
 standing. 
 
 11 
 
162 
 
 COBALT 
 
 Persalts of Iron. — Alkalies, and carbonates of the alka- 
 lies, all produce dark-brown precipitates. 
 
 Yellow prussiate of potash . An immediate dark-blue precipi- 
 tate. 
 
 Bed prussiate of potash . . No precipitate, but the solution 
 
 becomes green. 
 
 Solution of galls .... Black, passing to brown by 
 
 standing. 
 
 The difference between the action of red and yellow prus- 
 siates will be remarked. 
 
 Cobalt (Co 29.5). 
 
 Cobalt generally occurs in nature in combination with ar- 
 senic and sulphur, and accompanied by other metals. The 
 mineral in which it occurs was long known to miners, and was 
 called by them kohalds, or evil spirit of the mines, because its ap- 
 pearance often deceived them by giving a favorable impression 
 of mines which turned out erroneous, the cobalt being taken 
 for something else. Its distinct character as a metal was dis- 
 covered in 1733. Its oxide has long been extensively used for 
 giving a blue color to glass and porcelain. As a metal it is 
 brittle, of a reddish-gray color, and little more flexible than 
 iron. It has two oxides similar to iron. 
 
 Protoxide Co 0 
 
 Peroxide Co 3 0 3 .* 
 
 But there is no persalt of cobalt known equivalent to the per- 
 oxide. 
 
 Cobalt is easily dissolved in either hydrochloric or nitric 
 acids, and forms pink-colored solutions which produce crystals 
 of a beautiful red color. Solutions of these salts form sympa- 
 thetic inks. By writing upon clean paper with one of these solu- 
 tions, the writing is invisible when partly dry ; but by heating 
 the paper before a fire, the writing becomes blue, and disappears 
 again on cooling. If the heat applied be too strong, the 
 writing becomes black and permanent, a significan|fcract to the 
 dyer. Cobalt does not dissolve easily in sulphuric acid ; but a 
 sulphate may be prepared by adding sulphuric acid to the 
 oxide or carbonate, which is formed by adding a carbonate or 
 caustic alkali to the nitrate or hydrochlorate of cobalt. The sul- 
 phate salt has also a pink color, but is not so generally used as 
 
 * These oxides appear to combine together in various proportions. 
 
NICKEL. 
 
 163 
 
 the others. Salts of any of the acids may be prepared by dis- 
 solving the oxide or carbonate. They are all affected by heat 
 in the manner described. 
 
 Some of these salts might be very usefully employed in dye- 
 ing, were they obtained at a sufficiently low cost ; but they are 
 progressively becoming cheaper, and may therefore ere long 
 be made available in the dye-house. 
 
 A preparation of cobalt is used in bleaching, as smalt blue. 
 It is a compound of oxide of cobalt and alumina, prepared by 
 mixing a solution of salt of cobalt and alum, and precipitating 
 them together by an alkaline carbonate, as carbonate of soda, 
 drying the precipitate, and subjecting it to a red heat. The 
 process gives a beautiful blue mass, which is ground to an im- 
 palpable powder, and mixed commonly with some carbonate 
 of lime (chalk). Salts of cobalt give the following reactions 
 with other substances : — 
 
 Potash, soda and ammonia . . A green color by a little 
 
 exposure. 
 
 Carbonates of the alkalies . . Reddish precipitates, which 
 
 become blue by boiling. 
 
 • Phosphate of soda Blue precipitate. 
 
 Yellow prussiate of potash . . Green precipitate, which 
 
 changes to gray. 
 Red prussiate of potash . . . Reddish-brown precipitate. 
 Sulphurets of the alkalies . . . Black precipitates. 
 
 The slightest trace of cobalt may be detected by the blow- 
 pipe, by fusing a little borax, and adding a little of the sub- 
 stance suspected to contain cobalt; if it be really present, it 
 communicates to the borax a blue color, more or less intense. 
 
 Nickel (Ni 29.6). 
 
 Nickel occurs in nature combined with arsenic, iron, cobalt, 
 and sulphur. It was discovered in 1751. Isolated, it is a 
 silver-white metal, ductile, and malleable, and requires a heat 
 nearly equal to that of iron to melt it. It is much used in the 
 arts for alloying with other metals. It is the principal con- 
 stituent of German silver. Nickel combines with oxygen in 
 two proportions. 
 
 Protoxide Ni 0. 
 
 Peroxide Ni 2 0 3 . 
 
 There are no persalts of nickel equivalent to the peroxide 
 known. 
 
161 
 
 ZINC. 
 
 Sulphate of Nickel. — Sulphuric acid dissolves nickel with 
 difficulty. When the sulphate is required, the acid is applied 
 to the carbonate or oxide of the metal ; in this state it is easily 
 dissolved, and forms a beautiful green-colored solution. 
 
 Chloride of Nickel. — Hydrochloric acid, when dilute, dis- 
 solves nickel, and forms a chloride; the solution is emerald 
 green. 
 
 Nitrate of Nickel. — Nitric acid dissolves nickel easily, 
 and may be called its true solvent; the product is the nitrate, 
 of which the solution is also emerald green. All these salts 
 crystallize. 
 
 Carbonate of Nickel. — This salt is prepared by precipi- 
 tating the nitrate by a carbonated alkali, as carbonate of soda 
 or potash. It is a greenish-colored precipitate. The common 
 means of preparing the salts of nickel is by dissolving in nitric 
 acid, then precipitating and washing the precipitate; by adding 
 the required acid the precipitate is dissolved. "The acetate, or 
 oxalate, or any of the other salts, may easily be prepared in this 
 way. The use of any of these salts in the dye-house is very 
 limited. Their solutions are precipitated as follows: — 
 
 Alkalies 
 
 Ammonia, in excess . 
 Carbonate of the alkalies 
 Yellow prussiate of potash 
 lied prussiate of potash 
 Solution of galls 
 Phosphate of soda 
 Sulphuret of the alkalies 
 
 An apple-green precipitate of 
 hydrated oxide, insoluble in 
 excess. 
 
 Blue solution. 
 
 Green precipitate. 
 
 Greenish-white precipitate. 
 
 Yellow-green precipitate. 
 
 No precipitate. 
 
 White precipitate. 
 
 Black precipitate. 
 
 Zinc (Zn 32.6). 
 
 Zinc was discovered in the sixteenth century. It is very 
 abundant in nature, in combination with sulphur, and with car- 
 bonic acid. With the former, it is the ore called blende or black 
 jack ; with the latter, it is calamine. Zinc is a white metal with 
 a shade of blue, brittle, and of a crystalline structure. When 
 heated from the boiling point of water to 300°, it is ductile, and 
 admits of being rolled into sheets, in which state it has become 
 a most useful metal in the arts. At a red heat it rises into 
 vapor, and takes fire in air, burning with a white flame. It is 
 much used along with copper for making the common alloy 
 known as brass. 
 
 Zinc combines with oxygen in several proportions; but the 
 
NITRATE OF ZINC. 
 
 165 
 
 only one of its oxides which has been studied is the protoxide 
 ==Zn O. The salts found are the protosalts, equivalent to this 
 oxide. 
 
 Protoxide of zinc may be obtained either by burning the 
 metal, or by precipitating it by an alkali from its acid solu- 
 tions. It forms a white powder, which is soluble in all the 
 caustic alkalies. 
 
 Chloride of Zinc. — Hydrochloric acid acts rapidly upon 
 zinc, evolving hydrogen gas, thus: — 
 
 Hydrochloric acid Hydrogen gas. 
 
 Zinc Zn "^^ Chloride of zinc. 
 
 It crystallizes in white crystals, which are very deliquescent, 
 and often used on account of this property for keeping sub- 
 stances damp. It is even said to be employed by tobacconists 
 for keeping snuff and tobacco moist, a dangerous and most 
 reprehensible practice, if true. It is now very extensively used 
 for soldering instead of rosin. 
 
 Sulphate of Zinc. — This salt is easily prepared by acting 
 upon zinc with sulphuric acid slighty diluted: the action is 
 
 Sulphuric acid . . I |Fq* Hydrogen gas. 
 
 Zinc Zn.. Sulphate of zinc. 
 
 It crystallizes in white-colored crystals, which contain seven 
 proportions of water of crystallization, and dissolve in two and 
 a half times their weight of cold water. It is known in com- 
 merce as white vitriol, white copperas, and is produced in great 
 quantities in the soldering of platinum vessels. Articles of 
 this kind are soldered by the flame of the oxyhydrogen blow- 
 pipe, for which the hydrogen required is prepared by zinc and 
 sulphuric acid, and thus the sulphate becomes a product. 
 
 Nitrate of Zinc. — This salt is easily prepared by acting 
 upon the metal with nitric acid; it is a crystalline salt very 
 deliquescent, but not much used. 
 
 Acetates, oxalates, and salts of such milder acids, may be 
 prepared either by digesting the metal in the acids, or by act- 
 ing upon the oxide or carbonate found as a precipitate. The 
 salts of zinc are not much used in the dye-house; the pre- 
 cipitates formed from them are nearly white ; the sulphate 
 is used in several operations, where its elements may act an 
 important part without affecting the tint, as in the operations 
 of dyeing chrome yellows, &c. It is also used by calico-printers 
 in some of the operations of discharging. 
 
 The salts of zinc act towards other substances as follows: — 
 
166 
 
 CADMIUM. 
 
 Potash, soda, and ammonia . White precipitate, easily dis- 
 solved in an excess of the 
 alkali. 
 
 Carbonates of the alkalies . . White precipitate, not soluble 
 
 in excess, but soluble in 
 caustic alkalies. 
 
 Yellow prussiate of potash . . White precipitate. 
 Eed prussiate of potash . . . Yellowish-precipitate; fades 
 
 in the air. 
 
 Solution of galls No precipitate. 
 
 Sulphurets of alkalies White precipitate. 
 
 Chromic acid A purple-brown precipitate. 
 
 Cadmium (Cd 56). 
 
 This metal was discovered in 1818; it is found only in small 
 quantities, and often combined with zinc. The metal some- 
 what resembles tin in color; it is also soft and flexible, and 
 makes a crackling noise when bent. It melts easily, and passes 
 off as a gas at a heat of about 600°. It combines with oxygen 
 in equal proportions, forming the protoxide (Cd O), which has 
 an orange color, and is easily obtained by burning the metal 
 in air, er by precipitation from acid solution by a caustic alkali. 
 Prepared in this way, it is a white hydrate, and has one pro- 
 portion of water combined with it. This oxide is soluble in 
 ammonia, but not in soda or potash. 
 
 Cadmium is acted upon like zinc, both by sulphuric and 
 hydrochloric acids ; and forms crystallizable salts. Nitric acid 
 acts readily upon the metal to form the nitrate, which is crys- 
 tallized with difficulty. All these salts give white-colored 
 crystals. The salts of the milder acids, as the acetate, the 
 oxalate, &c, may be obtained by dissolving the precipitated 
 oxide or carbonate in the particular acid. 
 
 Potash and soda, and their carbonates, give white precipi- 
 tates, not soluble in an excess of reagent. 
 
 Ammonia — white precipitate soluble in excess. (The oxide 
 and carbonate, precipitated by the fixed alkalies, are all soluble 
 in ammonia.) 
 
 Yellow prussiate of potash . . White precipitate. 
 
 Eed prussiate of potash . . . Yellow precipitate. 
 
 Solution of galls No precipitate. 
 
 Sulphurets of the alkalies . . Beautiful yellow precipitate. 
 
PROTOXIDE OF COPPER. 
 
 167 
 
 Copper (Ou 31.7). 
 
 This is a very abundant and useful metal, and was known 
 in the earliest times. It is found in nature in great quantities, 
 in combination with sulphur, oxygen, and carbonic acid ; and 
 is separated from these combinations by various processes of 
 roasting and fusing. Copper is of a red color; is very malle- 
 able and ductile, and only inferior to iron in tenacity. It 
 requires a heat of about 1900° to fuse it. It combines with 
 oxygen in two proportions, namely: — 
 
 Suboxide or dinoxide Cu 2 0. 
 
 The suboxide is of a reddish brown color, which is not changed 
 by the air. If acted upon by dilute acids, a protosalt is 
 formed, and in strong hydrochloric acid there is formed a 
 subchloride=Cu 2 CI. This is a greenish or nearly colorless 
 solution, which undergoes decomposition by dilution; and if 
 precipitated by an alkali, oxygen is absorbed, and protoxide is 
 formed. If a portion of suboxide be put into a stoppered bottle 
 with ammonia, it is dissolved, and the solution is colorless at 
 first, but by admitting air it is oxidized, and the solution be- 
 comes blue. 
 
 Protoxide of Copper is black, and is formed upon the 
 surface of metallic copper when brought to a red heat, and 
 exposed to the air ; or it may be obtained by exposing the 
 carbonate, acetate, or nitrate, to a red heat. Alkalies added to 
 solutions of copper, precipitate the oxide as a hydrate of a blue 
 color, which becomes black by boiling. Oxide of copper dis- 
 solves readily in ammonia, and gives a deep blue-colored solu- 
 tion. 
 
 Copper combines with nearly all the acids, and the salts 
 produced are generally blue or green. Sulphuric acid, when 
 cold, does not dissolve copper, but at a boiling heat it acts 
 upon it readily, a portion of the acid suffering decomposition, 
 as under: — 
 
 Protoxide 
 
 Cu 0. 
 
 fS... 
 0... 
 
 One proportion of sulphuric , 0... 
 acid decomposed j 0... 
 
 Sulphurous acid 
 gas. 
 
 O... 
 H.. 
 
 One proportion of sulphuric ( S0 4 
 acid (H.. 
 One proportion of copper Cu. 
 
 .Water. 
 
 Water. 
 
 Sulphate of copper 
 
168 
 
 NITRATE OF COPPER. 
 
 Sulphate of Copper yields deep blue crystals, containing 
 five proportions of water, four of which are given off by heat- 
 ing the crystals to 212°, at which temperature they become 
 white. They are soluble in four times their weight of cold 
 water, and in twice their weight of boiling water. The salt is 
 prepared on the large scale, in the same manner as the sulphate 
 of iron ; that is, from the sulphurets of the metal. Great quan- 
 tities of it are produced by the metal workers in Birmingham 
 and elsewhere, in their cleaning and bronzing operations, 
 which are effected by the action of acids upon copper or its 
 alloys. As obtained in commerce, it is often impure, and is 
 often contaminated with iron, a very injurious ingredient for 
 most of the purposes to which this salt is applied in the dye- 
 house. This impurity can be detected by dissolving a little 
 of the salt in pure water, and adding ammonia in excess ; on 
 filtering through water, and washing the filter, the iron will be 
 obtained as a brown precipitate of peroxide. If the salt con- 
 tains much iron, it ought to be rejected. Zinc is often present, 
 but it has no deleterious effects farther than in lessening the 
 value of the salt. Sulphate of copper is known in commerce 
 and in the dye-house as blue vitriol, Roman vitriol, and blue- 
 stone. 
 
 Nitrate of Copper. — Nitric acid dissolves copper easily, 
 forming the nitrate ; the action is similar to that by which the 
 nitrate of iron is produced. 
 
 1 proportion of nitric acid < 
 
 N... 
 0... 
 O... 
 
 o... 
 
 0... 
 0... 
 0 .. 
 H... 
 
 3 proportions of nitric acid 
 
 3 proportions of copper 
 
 | 3Cu. 
 
 Binoxide of nitrogen. 
 
 Water. 
 3 Water. 
 
 3 Nitrate of copper. 
 
 Nitrate of copper crystallizes in deep blue crystals, which 
 deliquesce in the air, and are accordingly very soluble in water. 
 The salt acts rapidly upon tin; if a small crystal be crushed, 
 slightly moistened, and wrapped in tin foil, combustion takes 
 place by the rapid oxidation of the tin. The salts of copper 
 are very useful for oxidizing vegetable matters in solution, and 
 are often used for that purpose in the dye-house. 
 
 Chloride of Copper is made by digesting oxide of copper 
 
LEAD. 
 
 169 
 
 in hydrochloric acid, by which a double decomposition takes 
 place, as follows: — 
 
 Hydrochloric acid 
 Oxide of copper 
 
 Water. 
 
 Chloride of copper. 
 
 The solution of this salt is green, but it crystallizes from this 
 solution in blue-colored crystals. 
 
 Acetate of Copper {verdigris) is prepared by exposing sheets 
 of copper to the action of acetic acid {vinegar), sometimes in 
 solution, but more commonly in vapor. The salt is obtained 
 in beautiful dark-green crystals ; in this state it is a subacetate, 
 having one acetic acid to two of copper. Acetic acid combines 
 with copper in various proportions, and the verdigris of com- 
 merce is often composed of several salts, not by adulteration, 
 but formed in the process of manufacture. 
 
 Oxalate of Copper is of a light-green color, and is prepared 
 by digesting oxide of copper in oxalic acid. 
 
 Arseniate and the Arsenite of Copper are salts of a light- 
 green color, formed during the dyeing of arsenic greens — blue- 
 stone sages or ScheeWs green — for which the goods are passed 
 through strong solutions of arsenic and copper, and alkalies. 
 That these greens are still dyed argues little for mercantile 
 morality. This process of dyeing is dangerous, and the wind- 
 ing of the yarns, and other operations that follow, are more so, 
 and produce much serious mischief to the operatives. 
 
 Copper salts produce the following reactions: — 
 
 Potash and soda Greenish-blue precipitates, be- 
 come black with boiling. 
 
 Ammonia 
 
 Carbonate of alkalies 
 Yellow prussiate of potash 
 Red prussiate of potash . 
 Solution of galls . . . 
 Sulphurets of alkalies . 
 
 Deep-blue liquid. 
 Green precipitate. 
 Dark-brown precipitate. 
 Yellow-green precipitate. 
 Brow r n precipitate. 
 Black precipitates. 
 
 Lead (Pb 103.6). 
 
 This metal exists abundantly in nature, mostly in combina- 
 tion with sulphur, from which it is separated by exposing the 
 ore to a gentle heat; the sulphur becomes oxidized, and passes 
 off as sulphurous acid, and the lead melts, and runs off by a 
 channel prepared for it. 
 
 Lead has a bluish-gray color, is soft, and very malleable ; it 
 
170 
 
 PROTOXIDE OF LEAD. 
 
 does not oxidate readily in the air, except at the water-line 
 when it is partially immersed in that fluid, and more rapidly 
 still when the water is soft and pure. Hence lead vessels should 
 not be used to hold water for domestic use, as the oxides of 
 lead are all very poisonous. 
 
 Lead combines with oxygen in various proportions. 
 
 Suboxide of lead is the grayish-blue crust, formed upon 
 the surface of lead exposed to the air, and consists of two 
 equivalents of lead and one of oxygen, Pb 2 O. It may be 
 prepared artificially, by burning oxalate of lead in a retort; 
 the suboxide remains as a dark gray powder. 
 
 Protoxide of. Lead consists of lead and oxygen in equal 
 proportions, = Pb 0. It may be obtained by exposing metallic 
 lead at a red heat to a current of air ; the oxygen of the air 
 combines with the lead, and forms with it a semifluid mass. 
 As it cools, it crystallizes in concretions of a greenish-yellow 
 color. It is obtained on the large scale by cupellation — a 
 process of fusion to which lead is subjected in the process of 
 extracting the small admixture of silver it commonly contains. 
 The process is conducted as follows : A quantity of lead is put 
 upon a flat vessel made of bone-ashes (burned bones) placed in 
 a furnace ; when the lead is melted, a strong current of air is 
 blown upon the surface, which rapidly oxidates the metal ; at 
 the same time, the force of the current blows the oxide off, 
 which runs over the side of the vessel like water. The silver, 
 not being capable of oxidation, by this means is ultimately left 
 pure upon the bottom of the vessel. Lead is continually added, 
 until the silver remaining nearly fills this bone-ash vessel, which 
 is technically termed a cupel. 
 
 When the protoxide of lead is kept for some time, it falls 
 into a brick-red scaly crystalline powder, known in commerce 
 as litharge. This is the principal oxide from which the salts 
 of lead are prepared for the dye-house ; but it is generally to 
 some extent contaminated with iron, copper, and red lead, and 
 is also subject to much intentional adulteration. Litharge, of 
 good quality, possesses a crystalline lustre, and is completely 
 soluble by digestion in nitric acid. The amount of adultera- 
 tion, if it be brickdust, may thus be ascertained, as it remains 
 insoluble, and, by adding ammonia to the solution, the lead is 
 precipitated; if iron be present, the precipitate will have a brown 
 color ; if copper, the solution will be blue, but none of these 
 are deleterious to the dye. The protoxide of lead is also ob- 
 tained by adding a caustic alkali to a solution of a salt of lead ; 
 the oxide is precipitated as a white powder, soluble in an excess 
 of caustic alkali, and also in solutions of the alkaline earths, as 
 lime, with which it forms compounds more or less soluble. 
 
ACETATE OF LEAD. 
 
 171 
 
 Peroxide of Lead consists of two equivalents of oxygen 
 and one of lead = Pb 0 2 . It may be obtained by digesting 
 litharge in a boiling solution of chloride of lime {bleaching 
 powder). It is a powder of a dark brown color, and is not used 
 for preparing any salts of lead. 
 
 What is termed the fourth oxide of lead, consists of Pb 3 0 4 ; 
 but this is not generally considered to be a direct combination 
 of oxygen and lead in these proportions, but a mixture of the 
 second and third oxide just described, in the proportion of two 
 of the protoxide to one of the peroxide, 2 Pb O + Pb 0 2 , which 
 may be separated by digestion in dilute nitric acid ; the acid 
 combining with the protoxide, and liberating the peroxide which 
 remains undissolved. Whether the view we have stated of its 
 constitution be correct or not, is not very important, as this 
 oxide is not much used in the dye-house. It is known in com- 
 merce as red lead, or minium. 
 
 Carbonate of Lead ( White had) is prepared on the large 
 scale by exposing thin sheets of lead to the vapors of vinegar ; 
 the acid is decomposed and forms carbonic acid, which combines 
 with the lead. This salt is sometimes used for preparing salts 
 of lead, by dissolving it in the acid the salt of which is required. 
 
 Nitrate of Lead is prepared by dissolving litharge, or 
 metallic lead, in nitric acid, and evaporating the solution, which 
 leaves a crystalline mass, the crystals of which are white and 
 generally opaque, and soluble in 7| parts of cold water. The 
 nitrate of lead, when prepared in this way, contains one propor- 
 tion of oxide, and one of nitric acid ; but by boiling the salt for 
 some time over litharge, the acid combines with two, three, or 
 even six proportions of lead, forming what are termed basic 
 salts. This fact has been known to practical dyers for many 
 years, and is made available for the purpose of dyeing orange 
 color and dark shades of yellow. 
 
 Acetate of Lead (Sugar of Lead) may be obtained by ex- 
 posing metallic lead to the action of acetic acid, either as a 
 liquor or as a vapor, and to the air ; a portion of the acid is 
 decomposed, and carbonate of lead is formed, which is then 
 easily decomposed by another portion of the acid; the latter 
 combining with the lead, forms acetate of lead, and the car- 
 bonic acid is evolved. 
 
 Acetate of lead is prepared extensively by a variety of 
 modes. The first is by immersing a number of sheets of lead 
 in vinegar, so arranged that the uppermost sheets are exposed 
 to the action of the air. When they become covered with the 
 crust of carbonate, they are shifted to the bottom of the vat, 
 where the acid decomposes the carbonate aud forms acetate, 
 
172 
 
 ACETATE OF LEAD. 
 
 while the succeeding sheets are being exposed to the same 
 course of action. 
 
 Another process is to expose sheets of lead to the vapor of 
 vinegar ; the carbonate formed is collected and immersed in 
 strong vinegar. In both these processes, when the acid 
 appears to be saturated, or when it ceases to decompose the 
 carbonate, the solution is drawn into proper vessels and allowed 
 to crystallize. 
 
 Another process is to dissolve litharge in strong vinegar to 
 saturation. This is done by gradually sprinkling the litharge 
 in a vessel of vinegar subjected to a boiling heat ; the vinegar 
 is constantly stirred, to prevent the adhesion of the litharge to 
 the bottom and sides of the boiler. When a sufficient quan- 
 tity is dissolved, a moderate quantity of cold water is poured 
 into the solution, reducing it a little below the boiling point, 
 and it is allowed to settle; the clear fluid is then drawn off 
 into a separate vessel and allowed to crystallize. If the solu- 
 tion be colored, it is whitened by filtration through bone-black. 
 Common unrectified wood vinegar, or pyroligneous acid, is 
 much used for the preparation of acetate of lead for the dye- 
 work. It is known in the dye-house by the appellation of 
 brown sugar. 
 
 Basic salts or subacetates, are made by boiling common 
 acetate of lead with litharge. The tribasic acetate, a combina- 
 tion of three of lead to one of acid, is the best salt for dyeing 
 orange, deep yellow, and amber. It is prepared in the dye- 
 house by boiling a solution of sugar of lead with litharge ; and 
 adding to this a little lime. The proportions, however, vary 
 in different dye-houses. Those which ought to be employed 
 to produce the tribasic acetate, are six parts' of crystallized 
 acetate of lead, eight of litharge, and thirty of water, boiled 
 till the litharge is dissolved. The addition of small quantities 
 of lime causes a loss, as the lime combines with part of the 
 acetic acid forming acetate of lime, which, if these proportions 
 have been used, would prevent some of the litharge from being 
 dissolved. If the mixture be not long enough boiled, or if the 
 proportion of litharge be too small, the addition of lime insures 
 the conversion of the acetate of lead into the tribasic state, 
 though it is to be observed that this will be at the expense of 
 a portion of the lead intended for producing the color. We 
 have experienced much annoyance from this source ; and it 
 is well known in the trade, that when the lead is hastily 
 prepared for orange, it is a cause of great anxiety, and the 
 color obtained is frequently defective. As this is rather an 
 important point in the economy of the dye-house, we shall ex- 
 plain our view of the matter. If the proportions recommended 
 
CHLORIDE OF LEAD. 
 
 173 
 
 above be used, the following is the result — and we must bear 
 in mind that while the oxide of lead forms the basis of the dye, 
 the acid merely holds the lead in solution : The six pounds of 
 acetate of lead are composed of 4 lbs. oxide of lead, and 2 lbs. 
 acetic acid ; but when the 8 lbs. of litharge are dissolved, or, 
 as dyers say, taken up, the tribasic salt will consist of 12 lbs. 
 of oxide of lead and 2 lbs. of acetic acid ; that is, every ounce 
 of acid holds in solution 6 ounces oxide of lead. Now, if a 
 little lime, as we have often remarked, be put in along with 
 the litharge, the result will be as follows : Suppose that 50 lbs', 
 of cotton are to be dyed orange, and that if consumed the 6 lbs. 
 acetate of lead prepared as now stated, to give it a good color. 
 If 1J ounces of lime be mixed in, they will combine with 3 
 ounces of acid ; in this way 18 ounces of oxide of lead are not 
 taken up, and are therefore ineffective in the production of the 
 color ; while at the end of the process, the dyer is surprised to 
 find his color poor. We may notice that lead in the basic 
 state is not held in combination by a very great affinity, and 
 thus a very little counteractive influence precipitates it. The 
 presence of sulphates or carbonates in the water, which almost 
 all water contains, precipitates the lead ; hence the reason that 
 often, when the clear acetate solution is poured into a tub of 
 water ; the contents become milk-white by the formation of an 
 insoluble carbonate or sulphate. The lead is all lost for the 
 time, as it is rendered insoluble and useless as a dye. Every 
 ounce of carbonate renders useless five ounces of lead. The 
 softest water should be used for the lead solution, as, for ex- 
 ample, the condensed steam from an engine. When much lime 
 is added, it dissolves the lead, and forms a mordant quite as 
 good, if not superior, to that described, as we will have occa- 
 sion more fully to indicate when we come to treat of the pro- 
 cesses for dyeing oranges and yellows. Alkaline salts of lead 
 and oxide of lead, dissolved in alkalies, are now becoming 
 more generally used than the acid salts, and are superior for 
 most purposes. 
 
 Sulphate of Lead. — Sulphuric acid, when hot and con- 
 centrated, dissolves lead ; but the sulphate is precipitated by 
 dilution. It is an insoluble white powder, easily formed by 
 adding a solution of a soluble sulphate, as that of an alkali, to 
 any salt of lead. 
 
 Chlokide of Lead. — Lead dissolves slowly in hydrochloric 
 acid, forming a chloride which requires 135 times its weight 
 of cold water to dissolve it. Several sub-chlorides of lead are 
 also capable of being formed, but they are nearly all insoluble 
 in water. 
 
 All the soluble salts of lead are poisonous, and have a sweetish 
 
174 
 
 BISMUTH. 
 
 taste, except the sulphate, which is inert. Their reactions with 
 other substances are as follows: — 
 
 Soda and potash, give . . 
 
 Lime 
 
 Ammonia 
 
 Carbonates of alkalies . . 
 
 Oxalic acid 
 
 Yellow prussiate of potash 
 Eed prussiate of potash . . 
 Solution of galls .... 
 Chromates of potash . . . 
 Iodide of potassium . . . 
 Sulphurets of the alkalies . 
 
 Testing the Value of Lead Salts. — A very simple 
 method of testing the value of salts of lead, that is, of ascer- 
 taining the quantity of lead in a solution, is to dissolve say 10 
 grains of bichromate of potash (red chrome) in hot water, and 
 put the solution into a tall glass jar; then take a given weight, 
 say 100 grains of the lead salt, whether acetate or nitrate, and 
 dissolve in 100 measures (by the alkalimeter) of water ; add 
 this gradually to the chrome solution until the liquor above 
 the precipitate becomes colorless, or until a drop of the liquor 
 added to a drop of the lead solution on a glass plate is not 
 turned yellow\ The number of graduations taken to effect this 
 is noted ; then, as every 148.6 of bichromate of potash is equal 
 to 379.4 acetate of lead, or 830 nitrate of lead, the quantity 
 required by the 10 grains chrome is easily calculated — being 
 for acetate 25.6, and for nitrate 23 grains. All the solution 
 required above these measures will indicate impurities. The 
 average of 
 
 Commercial nitrate requires 24 grains. 
 " white sugar, 27 " 
 
 " brown sugar, 28 " 
 
 The quantity of lead in a solution is tested in the same way. 
 
 Bismuth (Bi 213 or 106.5). 
 
 This metal occurs in nature in the metallic state, and also in 
 combination with other substances. When found in the me- 
 
 White precipitates, soluble in ex- 
 cess. 
 
 White precipitate, soluble in ex- 
 cess. 
 
 White precipitate, insoluble in ex- 
 cess. 
 
 White precipitates, insoluble in ex- 
 cess, but soluble in caustic alkali. 
 White precipitate. 
 White precipitate. 
 No precipitate. 
 White precipitate. 
 Yellow precipitates. 
 Yellow precipitate. 
 Black precipitates. 
 
TIN". 
 
 175 
 
 tallic state, it is separated from the earths, through which it is 
 diffused, by a melting heat — the metal sinking to the bottom 
 of the crucible, and the earthy matters floating on the surface. 
 It is a white metal, with a reddish hue, very crystalline in 
 structure, volatilizes at a white heat, and burns in the air with 
 a pale blue flame, forming oxide of bismuth. The metal does 
 not tarnish by exposure to the air. It combines with oxygen 
 in several proportions, the principal of which are: the protox- 
 ide Bi 2 0 3 , formed by combustion, or calcination of the sub- 
 nitrate, and the bismuthic acid Bi 2 0 5 . These oxides appear to 
 combine together in several proportions. 
 
 Sulphate of bismuth may be prepared by dissolving the 
 oxide in concentrated sulphuric acid, and chloride of bismuth by 
 dissolving in hydrochloric acid. These salts are decomposed 
 by dilution. 
 
 Nitrate of Bismuth. — Nitric acid dissolves bismuth easily, 
 forming the nitrate, which crystallizes in beautiful white crys- 
 tals. This salt is also decomposed by water; indeed, all the 
 neutral salts of bismuth are precipitated by adding water to 
 their solutions, there being formed salts with the oxides. 
 
 The action of reagents upon the solutions of bismuth is as 
 follows : — 
 
 Potash, soda, and ammonia . 
 
 Carbonates of the alkalies . 
 
 Yellow prussiate of potash . 
 
 Eed prussiate of potash . . 
 
 Solution of galls . . . . 
 
 Iodide of potassium . . . 
 
 Chromates of potash . . . 
 
 Sulphurets of the alkalies . 
 
 . White precipitates, not soluble 
 
 in excess. 
 . White precipitates, not soluble 
 
 in excess. 
 . White precipitate. 
 . Pale-yellow precipitate. 
 . Orange-yellow precipitate. 
 . Brown precipitate. 
 . Yellow precipitates. 
 . Black precipitates. 
 
 Tin (Sn 59). 
 
 This metal has nearly the c*olor and lustre of silver ; it is one 
 of the few metals which were known to man at a very early 
 period of his history, and was extensively used in all countries, 
 both east and west, having any pretensions to civilization. 
 This was probably owing to the ores of the metal being easily 
 reduced to the metallic state, these being in general oxides ; so 
 that by merely fusing them with carbonaceous matter, such as 
 wood or coal, which combines with the oxygen, the metal is 
 fused, and sinks in the melted state to the bottom of the fur- 
 nace. 
 
176 
 
 TIN. 
 
 The principal localities for obtaining tin, are Cornwall in 
 England, Bohemia, Mexico, and the East Indies ; in the former 
 country, the metal has been wrought for many ages, and may 
 almost be said to be the first nucleus of civilization in this 
 country, as it formed the great mart where the civilized and 
 commercial Phoenicians obtained the tin which was so abun- 
 dantly used by them. The ore is found in Cornwall both in 
 veins traversing the primary rocks, and in small rounded 
 grains in the neighborhood of these rocks, imbedded in what 
 geologists term the alluvial deposit, signifying the deposit 
 formed by the washing away of the fragments of the primary 
 rocks with water. This gives the purest tin, and is distin- 
 guished by the name of stream tin. The ore obtained from 
 the veins is generally contaminated with other metals, such as 
 iron, copper, arsenic, and the like, but is partially purified by 
 roasting, washing out the decomposed foreign substances, and 
 smelting in a kind of cupola. Several other operations of re- 
 fining follow this, which need not be detailed ; but there are 
 always some few of the impurities remaining in a portion of 
 the tin. That portion which contains these impurities is termed 
 block tin. The pure grain tin is heated till it becomes brittle, 
 and is then let fall from a height, which splits it into small bars 
 or prisms, and in this state it is found in commerce. These 
 bars, in bending, make a peculiar crackling noise, and become 
 heated ; phenomena probably owing to the separating of their 
 parts, and the sudden fracture caused by bending. 
 
 Tin is very extensively used in dyeing and printing both 
 cotton and woollen. Its introduction as a mordant may be con- 
 sidered as forming an era in the art of dyeing, and, like many 
 other important improvements in this art, was the result of ac- 
 cident, an account of which is given by Berthollet as follows : 
 " A little while after the cochineal became known in Europe, 
 the scarlet process by means of the solution of tin was disco- 
 vered. It is stated that about the year 1630, Cornelius Dreb- 
 bel observed, by .an accidental mixture, the brilliancy which 
 the solution of tin gave to the infusion of cochineal. He com- 
 municated his observation to his son-in-law, Kuffelar, who was 
 a dyer at Leyden. He soon improved the process, kept It a 
 secret in his work shop, and brought into vogue the color which 
 bore his name." 
 
 Soon afterwards, a German chemist found out the process of 
 dyeing scarlet by means of the solution of tin. He brought 
 his secret to London in 1643 ; it became known to others, was 
 soon afterwards diffused over Europe, and its applications be- 
 came more extended, as, whenever a new dye-drug was intro- 
 
PROTOCHLORIDE OF TIN. 
 
 177 
 
 ducecl into the art, the solution of tin was universally applied, 
 by which means it became a standard mordant for the various 
 dyewoods, such as logwood, Brazil-wood, and the like. 
 
 Copper boilers, used for dyeing woollens and silks, have gene- 
 rally a part covered jvith or made of tin, which is intended to 
 prevent the acid mordant from acting upon the copper, and 
 this it does by a galvanic action, the tin being slowly acted 
 upon, while the copper is protected. 
 
 Tin combines with oxygen in three different proportions : — 
 
 Protoxide Sn O. 
 
 Sesquioxide Sn 2 0 3 = Sn 0, Sn 0 2 . 
 
 Peroxide So 0 2 . 
 
 There are salts of tin corresponding to these oxides, all more 
 or less useful in dyeing. 
 
 Protoxide of Tin is formed by precipitation from a solu- 
 tion of the protochloride of tin by carbonate of potash or soda. 
 It is obtained as a white powder, wh^ch is a hydrate of the 
 oxide, and which, if heated to 176°, loses its water of combina- 
 tion, and becomes black, and may be kept in this state; but 
 if brought to a red heat, or into contact with a redhot body, it 
 takes fire, and in burning passes into the state of peroxide. 
 The white hydrated oxide is easily dissolved in acids, and also 
 in solutions of the alkalies, but these alkaline solutions are not 
 permanent ; for if diluted with water, a portion of the tin is 
 precipitated, and another portion passes into the state of per- 
 oxide. Also, when brought into contact with other oxides 
 which yield their oxygen freely, such as peroxide of iron, a 
 reaction takes place ; the iron is reduced to a lower state of 
 oxidation, and the tin is raised to a higher. These reactions 
 and properties are taken advantage of in many of the opera- 
 tions in dyeing. 
 
 The protoxide of tin and its protosalts all come under the 
 denomination of stannous salts; and it may be remarked of 
 them, as a general characteristic, that they all absorb oxygen 
 from the air by exposure. 
 
 Protochloride of Tin (Salts of Tin). — This salt is pre- 
 pared by dissolving tin in strong hydrochloric acid, with the 
 assistance of heat, the solution evaporating and crystallizing in 
 the ordinary way. The crystals were formerly said to contain 
 three proportions of water, about 22 per cent.; but according 
 to a recent investigation by Dr. Penney, they contain only two 
 proportions. The crystals dissolve in a small portion of water; 
 but if put into a large quantity, the whole becomes milky, and 
 a white powder separates, which is an oxychloride of tin. A 
 complete and clear solution of salts of tin in water cannot be 
 ,12 
 
178 
 
 DEUTOXIDE OR SESQUIOXIDE OF TIN. 
 
 retained for any length of time on account of the great attrac- 
 tion which this salt has for oxygen. A little hydrochloric acid 
 put into the water, however, has the effect of greatly retarding, 
 and, indeed, of almost wholly preventing this decomposition. 
 In establishments where the dyers prepare their own salts of tin, 
 they do not crystallize it, and as there is nearly always an ex- 
 cess of acid, some of the phenomena mentioned may not have 
 been observed. 
 
 On adding potash to salts of protochloride of tin, a double 
 salt is formed of chloride of tin and chloride of potassium, 
 which may be crystallized. 
 
 Protosulphate of Tin. — Sulphuric acid dissolves tin 
 slowly, and forms a thin, pasty-looking mass, which, by evapo- 
 ration, yields crystals. This salt is not used in the dye-house ; 
 it is, indeed, immediately decomposed by aqueous dilution. 
 
 Protonitrate of Tin. — Protoxide of tin dissolves easily in 
 dilute nitric acid, but it cannot be concentrated, from its liability 
 to pass into the state of^peroxide. When nitric acid of specific 
 gravity 1.114 = 23 of Twaddell, is poured upon the metal, it 
 dissolves it rapidly, and much heat is evolved, which ought 
 to be kept down by placing the vessel containing the acid in 
 cold water. If this be properly done, a protonitrate of tin is 
 formed, the action being 
 
 Nitric acid ^ Hydrogen gas. 
 
 Tin ... . Sn.. — - Nitrate of tin. 
 
 But should the heat be allowed to rise too high, the nitric acid 
 is also decomposed, and the tin passes into a higher state of 
 oxidation. Also, if the action is very rapid, ammonia is formed 
 between the hydrogen and nitrogen, and consequently a double 
 salt of tin and ammonia; but the greater proportion of the tin 
 is precipitated as a white pasty mass of peroxide. 
 
 Tartrate of Potash and Tin is prepared by dissolving 
 protoxide of tin in bitartrate of potash (tartar or cream of tar- 
 tar). This forms a very soluble salt, occasionally used in dye- 
 ing woollens; but in this case the tartar is added to the salts 
 of tin. 
 
 A combination of the protoxide of tin, arsenic, and soda, has 
 been patented as a salt in calico-printing, under the name of 
 Stanno-Arsenite of Soda. 
 
 Deutoxide, or Sesquioxide of TiN=Sn 2 0 3 , can be pre- 
 pared by adding to a saturated solution of protochloride of tin 
 some newly-precipitated peroxide of iron; a double decomposi- 
 tion takes place as follows : — 
 
PEROXIDE OF TIN. 
 
 179 
 
 2 proportions proto- (2 CI 
 
 chloride of tin (2 Sn 
 1 proportion of per- f 2 Fe. 
 oxide of iron "^3 0.. 
 
 2 Protochloride of iron in 
 solution. 
 
 Sesqnioxide of tin preci- 
 pitated. 
 
 Strong hydrochloric acid dissolves this oxide, and forms with 
 it a sesquichloride, thus: — 
 
 The other salts corresponding to this oxide have not been 
 examined; but the distinctive character of the oxide itself may 
 be made evident by the two following reactions : Ammonia 
 dissolves this oxide, but does not dissolve the protoxide ; and 
 hydrochloric acid dissolves this oxide, but does not dissolve the 
 peroxide. There can be little doubt but that an investigation 
 into the sesquioxide and its salts would explain many of the 
 hitherto unexplained phenomena of dyeing; -and that it is highly 
 probable that the formation of salts of this class plays a con- 
 siderable part in many dyeing operations ; such as those pro- 
 cesses in which chloride of tin is mixed with pernitrate of iron, 
 as for royal blues, &c. 
 
 Peroxide of Tin. — The ores of tin, termed tinstone, are 
 mostly peroxide. They are black, shading to brown ; in this 
 state, the oxide is not soluble in acids, but becomes so by pre- 
 vious ignition with an alkali. 
 
 When metallic tin is put into dilute nitric acid, and the action 
 allowed to proceed rapidly, or when heat is applied, there is 
 formed a hydrated peroxide, as a white mass, which contains 
 11 proportions of water. Dilute hydrochloric acid dissolves 
 this oxide slightly, but it is not soluble in nitric or sulphuric 
 acids. If acted upon by hydrochloric acid, and allowed to 
 stand for some time, and the supernatant liquor then poured 
 off, the remaining insoluble oxide is soluble in water. If this 
 hydrated peroxide be dried with heat, it loses its water, and 
 passes into the same state as the ore. Boiling water, poured 
 upon it, will effect similar changes. 
 
 The peroxide of tin is obtained easily by precipitation from 
 a solution of bichloride, by adding an alkaline carbonate. 
 Thus prepared, and in this condition, the peroxide is easily dis- 
 solved in hydrochloric acid, either strong or dilute; but if 
 this oxide be heated in any way, as by pouring boiling water 
 upon it, strong hydrochloric acid will not dissolve it, and dilute 
 acid only partially. The oxide has now indeed every property 
 
 1 Sesquioxide of tin | 
 3 Hydrochloric acid | 
 
 3 Water. 
 
 1 Sesquichloride of tin. 
 
180 
 
 PERCHLORIDE OF TIN. 
 
 that it has when formed by the nitric acid process. It is also 
 soluble in pure water, after being made into a paste with 
 strong hydrochloric acid, but the addition of a little of this 
 acid to the watery solution will precipitate it. 
 
 The changes effected upon this oxide by heat or applying 
 boiling water, are supposed to be owing to its state of hydra- 
 tion; but be that as it may, these peculiarities ought to attract 
 the attention of the practical dyer; as the annoyances to which 
 they give rise are very considerable, and only require the 
 exercise of a little care to be avoided. The hydrated peroxide 
 of tin is very soluble in caustic alkalies. 
 
 The peroxide of tin has been termed stannic oxide and stan- 
 nic acid, as it has certain acid properties. It combines with 
 alkalies, and forms salts. y 
 
 Perchloride of Tin {Per muriate of Tin). — When tin is dis- 
 solved in a mixture of hydrochloric and nitric acids, the salt 
 formed is generally the perchloride = Sn Cl 2 , and is conse- 
 quently that most generally used in the dye-house, where 
 almost all salts are prepared by a mixture of the acids. But 
 from what has been stated in reference to the separate oxides 
 and salts, it will be evident that this subject stands in need of 
 farther investigation ; the modes of preparation are so varied 
 in the proportions of each acid, in the qualities of tin used, and 
 in the manner of adding the tin ; all and each of these circum- 
 stances, it will be observed, make a difference. If tin is added 
 too rapidly, the action and heat may be so violent as to pre- 
 cipitate some of the oxide in an insoluble state; if added too 
 slowly,and at a temperature too low, there may be protochlorides 
 formed, or mixtures of the different salts, in very varied pro- 
 portions; and hence the cause of the irregularity both in 
 quality and kind of color produced by tin mordants. Per- 
 chloride of tin is generally formed by dissolving crystals of 
 the protochloride in a small portion of water, adding nitric 
 acid, and applying heat, or by passing a steam of chlorine gas 
 through a solution of salts of tin. These are termed in the 
 dye-house oxychlorides of tin. 
 
 Dr. Penney, in a recent communication to the Chemical 
 Society, has recommended a simple means of testing the quan- 
 tity of tin present in a solution of salt in the proto-state, founded 
 upon the reduction of chromic acid to oxide of chromium, by 
 protoxide of tin. The method recommended for salts of tin is 
 the following: 100 grains of the crystals are put into a vessel 
 with 20 oz. of water, and half an ounce of hydrochloric acid ; 
 83 J- grains bichromate of potash are dissolved in warm water, 
 and placed in an alkalimeter, the whole measuring 100 gradua- 
 tions; this solution is added by degrees to the solution of tin, 
 
SPIRITS OF TIN". 
 
 181 
 
 which takes a rich green color. The solution of chrome is 
 added, until a drop taken out and put upon a drop of acetate 
 of lead, on a glass or paper surface, gives yellow. If the tin 
 solution is more dilute, and put into a large glass jar, the green 
 tint, whenever the chrome is in excess, is perceptibly yellow. 
 A little experience renders the operation simple. The quantity 
 of bichromate (83J grains) is« equal to 100 grains of pure 
 metallic tin; hence every graduation of the chrome solution 
 taken to effect the change described, is equal Jbo one grain of 
 tin. As 83 J grains of bichromate of potash may not be soluble 
 in one measure of the common alkalimeter, two measures may 
 be taken; in that case, two graduations will indicate one grain 
 of tin in the salt tested. 
 
 Solutions of tin, such as are sold to calico-printers under 
 /the term single and double muriates, may be tested by taking a 
 measured quantity of the solution and treating it in the same 
 manner. Or, as recommended by Dr. Penney, by taking a 
 weighed quantity of the solution of tin, say 500 grains, and 
 making up with water to fill the alkalimeter ; then dissolve 
 41.6 grains of bichromate of potash in warm water, and add 
 the solution of tin to this very cautiously, as long as the tint 
 remains of an olive-green color, or until a drop taken out and 
 added to a drop of lead in solution gives a yellow color. 
 Whenever the yellow ceases to be obtained, the operation is 
 complete. Finally, by dividing 1000 by the number of gradua- 
 tions taken of the tin solution, the percentage of the tin is 
 ascertained. Thus, say that 41.6 of bichromate of potash re- 
 quired 38 graduations of tin solution to reduce the chromic 
 acid, then 
 
 38)1000(26.3 = percentage of tin in solution.* 
 
 This test only applies to tin in solution in the proto-state, 
 but gives no change in the persalts of tin, and is therefore not 
 applicable to many of the spirits used in the dye-house. 
 
 Spirits. — The solutions of tin, in the technical language of 
 the dye-house, are termed spirits, with an affix to each mode of 
 preparation, to denote their special application, such as red 
 spirits, yellow spirits, plumb spirits, &c. The preparation of 
 these spirits is a matter of much pride amongst dyers, and each 
 has some little peculiarity which he keeps to himself, and on 
 the virtue of which he supposes all his success depends. These 
 peculiarities are generally in the proportion of the acids and 
 the tin, and the manner of mixing them. However, as may be 
 supposed, they are not equally answerable for all the purposes 
 
 * Journal of Chemical Society, for 1851. 
 
182 
 
 SPIRITS OF TIN. 
 
 to which they are applied; hence the reason that we find one 
 dyer best at reds, another at purples, another at blacks, and 
 another at browns. 
 
 We will here give a few practical methods of preparing these 
 several spirits, reserving our remarks upon their varieties and 
 effects to our general observations on mordants, to which we 
 will devote a separate chapter, in order that we may be able to 
 go fully into the subject. 
 
 The first process in preparing spirits is, to feather the tin. 
 This is done by melting it in an iron ladle, and pouring it, when 
 in a melted state, into a vessel filled with cold water, the 
 hand to be held as high as possible, so that it may pour more 
 in drops. The appearance of the tin in this state is beyond 
 description beautiful. By this process of feathering, a very 
 extended surface of metal is exposed to the acid, which facili- 
 tates its solution very much. 
 
 Eed Spirits. — If red spirits be wanted, that is, a mordant for 
 dyeing red upon cotton by Brazil-wood, the general method is 
 to take three measures of muriatic acid, and one of nitric acid, 
 then add the tin by degrees to this mixture so long as the acids 
 continue to dissolve the metal ; care ought to be taken not to 
 add it too rapidly, but bit by bit, adding one piece just as the 
 other is dissolved. We know that this is not generally 
 attended to, as one handful of the metal is put in after another, 
 at certain and too often irregular intervals of time, giving very 
 annoying results. When the metal is put in too rapidly, or 
 too much at once, the action becomes violent, the solution gets 
 heated, the nitric acid is decomposed, ammonia is formed in the 
 solution, and, when the solution cools, a quantity of peroxidized 
 tin falls to the bottomas a gelatinous precipitate, creating much 
 loss. When spirits thus prepared are used for a brilliant red 
 upon cotton by Brazil-wood, the proper hue is never obtained, 
 the color being always more or less brownish. The propor- 
 tions of the acids for preparing the red spirits are not invariably 
 three to one ; the mixture varies from half and half to five to 
 one, depending upon the taste and experience of the dyer. 
 Some dyers only dissolve a given quantity of the metal to the 
 pound weight of the mixed acids, varying from one and a half 
 to three ounces to the pound ; but according to our experience, 
 the acids, in whatever proportions they are mixed, ought to be 
 saturated, at least so far as they will become saturated, observ- 
 ing the precautions described above. We have also found that 
 when much nitric acid is used, the reds are generally deeper in 
 color, and have a very great tendency to turn brown, especially 
 if the goods be dried by heat; but when the muriatic acid pre- 
 
OXALATE OF TIN. 
 
 183 
 
 vails, the color obtained has more of the crimson or rose tint, 
 and is not so liable to become brown in drying. 
 
 Plumb Spirits.— This solution is prepared by dissolving tin 
 in hydrochloric acid, diluted with about a seventh of water, 
 adding two ounces of tin to every pound weight of acid. The 
 tin, as in other cases, ought to be added gradually. Some, 
 however, add nitric acid, and prefer it thus mixed, and others 
 add as much tin as the acid will dissolve when cold. 
 
 Barwood Spirits. — The method given for the preparation 
 of this solution is six measures muriatic and one of nitric acid, 
 adding tin gradually until white bubbles begin to rise to the 
 surface, allowing the solution to stand for twelve hours before 
 using it, a rather uncertain test of quantity of tin, and of the 
 quality of the spirits. 
 
 Yellow Spirits.— This solution is now seldom used ; it was 
 applied as a mordant for the dyeing of yellow by quercitron 
 bark, and was merely the substitution of sulphuric acid for 
 the nitric acid of the common red spirits. It was proposed by 
 Dr. Bancroft as a question of cheapness in the preparation of 
 scarlet spirits, and was afterwards much used, as stated, for 
 dyeing yellows, as its name implies. By this method of pre- 
 paration, the tin was generally in the proto-state, which gave it 
 a peculiarity in relation to the common red spirits, as it afforded 
 bluer tints with red woods when used as a raising or alterant. 
 The tin spirits, as double and single muriates, the salts of tin 
 dissolved in water and muriatic acid, and the metallic tin dis- 
 solved in hydrochloric acid {plumb spirits), all have the same 
 effect. Some dyers, however, use the red spirits for alterants 
 and dyeing yellows. 
 
 Instead of using hydrochloric acid for preparing spirits, many 
 woollen dyers use sal-ammoniac or common salt, adding it to 
 nitric acid in the proportion of 6 lbs. nitric acid to 1 of water 
 in which 1 lb. sal-ammoniac is dissolved, and then adding 10 
 oz. of tin. 
 
 Acetate of Tin is prepared by adding a solution of acetate 
 of soda to protochloride of tin ; common salt is formed and 
 acetate of tin; the former is not hurtful to the dyer. 
 
 Oxalate of Tin may be formed in the same way, by using 
 oxalate of soda, or by dissolving precipitated protoxide of tin 
 in oxalic acid. 
 
 In dissolving tin in hydrochloric acid, it is often observed 
 that towards the end of the process, when the tin is in the solu- 
 tion, parts of the metal seem to dissolve, while other parts 
 become coated with a crystalline substance, soluble only with 
 much difficulty, and occasioning both annoyance and loss. 
 This is caused by one portion of the solution becoming denser 
 
184 
 
 TITANIUM. 
 
 than other portions, a galvanic action being induced between, 
 those parts of the tin in the weaker portion of the solution, 
 and the parts in the stronger, consequently depositing the tin 
 upon the metal in the strongest parts of the solution. This 
 evil can be prevented by occasionally stirring the solution. 
 
 The following is the reaction of solutions of other substances 
 on the protosalts of tin : — 
 
 Potash and soda . . . White precipitates, soluble in excess. 
 
 Ammonia ditto, insoluble in excess. 
 
 Carbonates of the alkalies ditto, soluble in caustic alkali. 
 Yellow prussiateof potash, White precipitate. 
 Red prussiate of potash, ditto. 
 Galls in solution . . . Slight yellow precipitate. 
 Chloride of gold . . . Deep purple precipitate (purple of 
 
 Cassius). 
 
 Sulphurets of alkalies . Brown precipitates. 
 With the persalts of tin : — 
 
 Potash and soda . . . White precipitates, soluble in excess. 
 
 Ammonia ditto, ditto. 
 
 Carbonates of the alkalies ditto, soluble in caustic alkali. 
 Yellow prussiate of potash No precipitate. 
 Red prussiate of potash ditto. 
 Solution of galls . . ditto. 
 
 Sulphurets of the alkalies Yellow precipitates, soluble in caus- 
 tic potash. 
 
 Titanium (Ti 25). 
 
 This metal was discovered in 1791. It is generally found in 
 nature in combination with iron; a great number, indeed, of 
 the iron ores of this country seem to contain traces of this 
 metal. It regularly makes its appearance in the blast-furnace, 
 combined with cyanogen and nitrogen, in the form of copper 
 colored cubes. Titanic acid is soluble in concentrated muriatic, 
 and better still, sulphuric acid, but becomes precipitated by 
 diluting and boiling the solution. It combines in three propor- 
 tions with oxygen, forming: — 
 
 Protoxide =Ti 0. 
 
 Sesquioxide . = Ti 2 0 3 
 
 Peroxide =Ti 0 2 . 
 
 The latter oxide, on account of its combining with the alkalies, 
 and forming soluble salts with them, has been termed titanic 
 acid. 
 
CHROMIUM. 
 
 The salts formed by the action of acids upon this metal "have 
 not been much studied; those which have been investigated' 
 most carefully are the salts formed by the peroxide or titanic 
 acid. Solutions of these salts give a brown precipitate with 
 galls ; but all the compounds of this metal are very intractable, 
 and being besides very scarce, they are of little use in the arts. 
 
 Chromium (Or 26.2). 
 
 This metal is found in considerable quantities in nature, 
 combined with lead and iron. The latter (chrome iron) is its 
 principal ore. It is found in America and in different parts of 
 the Continent of Europe; also in Shetland, and in Fifeshire in 
 Scotland. The composition of the ore is Fe 0 + Cr 2 0 3 . 
 
 The metal was discovered in 1797 by Vauquelin. It ap- 
 proaches to cast-iron in appearance, but has only been obtained 
 in the state of powder. It is very difficult to fuse, and does 
 not undergo oxidation by exposure to the air. The metal is 
 not acted upon directly by the common acids; but may be ob- 
 tained in combination with acids, by decomposing some of its 
 salts or oxides, of which there are two, namely — 
 
 Peroxide Cr 2 0 3 . 
 
 # Chromic acid Cr 0 3 . 
 
 The last (chromic acid) forms the acid of the salts named chro- 
 mates. The oxide of chromium exists combined with iron in 
 the ore, as stated above ; it is not, however, obtained from the 
 ore, but by acting upon some of the salts of chromic acid. It 
 is of a beautiful green color, and may be prepared by various 
 methods ; e. g. take 
 
 1 part bichromate of potash, 
 
 1J part sal-ammoniac, 
 
 1 part carbonate of potash, 
 
 and ignite this mixture in a crucible; the chromic acid is de- 
 composed, and the oxide formed. By digesting what remains 
 in water, the oxide is obtained as an insoluble powder. An- 
 other and more easily-practised method for the dye-house, is 
 that adopted on the Continent, and is as follows: Take 9 lbs. 
 of bichromate, of potash, and dissolve in 5 gallons of boiling 
 water; then, into a boiler containing 23 gallons of boiling 
 water, put 10 lbs. of the white oxide of arsenic; boil for ten 
 minutes, and allow the liquor to settle. The clear is then 
 mixed with the solution of bichromate of potash, stirring all 
 the time, when very soon the hydrated oxide of chrome is 
 
186 
 
 SULPHATE OF CHROMIUM. 
 
 formed and precipitated. After the whole is cool, it is put 
 upon a filter, and the oxide which remains upon the filter is 
 washed with boiling water. If a little hydrochloric acid be 
 added, the chrome oxide is obtained as a green solution. This 
 oxide has long been used to give a green color to glass and 
 porcelain, and has lately been introduced and is now exten- 
 sively used in calico printing. It is also partially used in the 
 dye-house for dyeing colors of various tints, all of which have 
 the valuable property of permanency. 
 
 Chloride of Chromium. — The oxide of chromium dissolves 
 readily in hydrochloric acid, and forms a chloride, which has a 
 deep green color and a strong acid reaction. Evaporated nearly 
 to dryness, there are produced red-colored scales, which give a 
 green solution with water. The following method for the pre- 
 paration of the chloride has been recommended : Hydrochloric 
 acid is diluted with water until the acid no longer gives off 
 fumes; it is then heated, and, when hot, as much of the oxide 
 of chromium, prepared by the arsenic solution, is added as the 
 acid will dissolve : the whole is then left to settle, and the clear 
 is taken off. This contains some free acid, which would act 
 upon the cotton fibre ; to remove it, and obtain the salt in a 
 neutral state, potash lye is poured in gradually,* until the oxide 
 of chromium begins to be precipitated. The solution thus 
 prepared has a dark-green color, and is used for several opera- 
 tions in dyeing. Preparations of this salt, or rather mixture 
 of salts, have been long used in calico printing. These are 
 made by mixing together chromate of potash, hydrochloric 
 acid, and tartaric acid, in a great variety of proportions, giving 
 green tints of various depths, according to the mixture used. 
 
 Sulphate of Chromium. — Sulphuric acid added to oxide 
 of chromium dissolves it, and forms a green-colored solution, 
 which does not crystallize. If evaporated to dryness, it loses 
 its solubility in water; but by adding sulphate of potash or a 
 solution of potash, taking care not to precipitate any of the 
 oxide, there is formed a double salt, termed chrome alum. The 
 solution of this double salt is a bluish-purple; it crystallizes 
 easily, giving dark purple colored crystals; but care must be 
 taken that the solution is not heated to the boiling point, as it 
 is thereby turned green, and yields no crystals. 
 
 Oxalate, acetate, tartrate, &c, of chromium, may be ob- 
 tained by dissolving the oxide in any of these acids; they all 
 give green colored solutions. If we mix together one part of 
 bichromate of potash, two of crystallized oxalic acid, and two 
 of binoxalate of potash, and dissolve the mixture in boiling 
 water, a salt is formed, which crystallizes in nearly black-co- 
 lored crystals. It is a double-oxalate of chromium and potash. 
 
CHROMIC ACID. 
 
 187 
 
 Chromic Acid. — Salts of this acid are prepared directly 
 from the chrome iron ore; and the acid is obtained by de- 
 composing these salts. Chromic acid is of a beautiful deep 
 orange color, approaching to scarlet, and may be obtained in a 
 crystalline form. Various methods have been proposed for 
 preparing it; the following, by Mr. Robert Warrington, is 
 probably the most simple: "Take 100 measures of a cold 
 saturated solution of bichromate of potash (prepared by boil- 
 ing, and then allowing the solution to cool, and deposit the ex- 
 cess of the salt), and add to this from 120 to 150 measures of 
 concentrated sulphuric acid; the latter should be free from 
 sulphate of lead, as otherwise it would fall as chromate and 
 sulphate of lead with the chromic acid on dilution with the 
 bichromate. The mixture is then allowed to cool, and the 
 chromic acid gradually crystallizes in beautiful dark crimson 
 needles. Decant the fluid part, and place the crystals with the 
 adhering sulphuric acid on a thick flat tile of biscuit porcelain ; 
 another tile is then to be placed upon the crystals, and the 
 whole submitted to a pressure for a considerable time. On re- 
 moving the chromic acid, it will be found in a perfectly dry 
 state, and yielding a mere trace of sulphuric acid on examina- 
 tion."* 
 
 Chromic acid may also be prepared from the chromate of lead, 
 which results from the mixture of a salt of lead and bichromate 
 of potash at the bottom of the chrome tubs used in dj^eing 
 yellows. Two parts of strong sulphuric acid being added to 
 one part of dry chromate of lead slightly heated, and allowed 
 to stand for about twelve hours, water is then added, when the 
 lead is precipitated as a sulphate, and the chromic acid, mixed 
 with a little sulphuric acid, remains in solution. The liquid is 
 decanted and evaporated at a boiling heat; on cooling, the 
 greater portion of the chromic acid separates in beautiful car- 
 mine-red crystals. If the process be carefully conducted, a 
 great portion of what is now little better than thrown away, 
 might be made useful by a trifling addition of expense. 
 Another method of preventing waste is to add potash to the 
 solution, so as to form chromate and sulphate of potash, which 
 may afterwards be separated by crystallization. 
 
 Chromic acid combines with the different bases, and forms 
 a series of important salts. With potash it combines in two 
 proportions, forming what is termed the yellow and the red 
 chromate of potash. The yellow chromate of potash may be 
 prepared by adding to two pounds of red chromate one pound 
 of caustic potash ; it crystallizes in small crystals of a rich 
 
 * Proceedings of the Chemical Society, vol. i. 
 
183 
 
 BICHROMATE OF POTASH. 
 
 deep lemon color, composed of one proportion of acid and one 
 of potash. This salt is not much used in the arts. 
 
 Bichromate (Red Chromate) of Potash. — This salt may- 
 be prepared from the yellow chromate by adding a little sul- 
 phuric acid, which combines with a portion of the potash, 
 leaving two proportions of chromic acid in union with one pro- 
 portion of potash which crystallizes in large square tabular 
 crystals of a rich orange-red color. This is the salt used in 
 the arts, not only for dyeing, but for the preparation of other 
 chrome compounds, and is prepared on the large scale in the 
 following manner: Chrome iron ore, after being finely ground 
 and sifted, is mixed with a quantity of dried nitrate and car- 
 bonate of potash. This mixture is thrown into a reverberating 
 furnace, and subjected to a powerful heat, being occasionally 
 stirred. When perfectly calcined, the mass is raked out and 
 dissolved in water. It is then boiled for several hours, after 
 which the insoluble portion is allowed to settle, and the solution 
 decanted; this is evaporated, and leaves the yellow chromate 
 of potash crystallized. The chemical changes which take place 
 in the furnace, are these: First, the decomposition of the nitre, 
 giving off oxygen, which combines with the oxide of chromium, 
 and forms chromic acid; this unites with the potash of the 
 nitrate and of the carbonate, and forms the yellow salt, which 
 is soluble in water, and afterwards separated as described. It 
 contains also soluble impurities, such as caustic potash, silicate 
 and aluminate of potash, which are separated by the succeed- 
 ing operations of boiling and crystallization. 
 
 The bichromate, which is the salt used in dyeing, is pre- 
 pared from the yellow salt obtained as above. Into a concen- 
 trated solution is poured acetic or sulphuric acid. The latter 
 acid, though often used, is not well adapted for the purpose, 
 as the sulphate of potash formed is very difficult to separate 
 from the chromate, and constitutes a serious adulteration. 
 Acetic acid is preferable, and is now generally employed. The 
 quantity of the acid is so regulated, that it combines with the 
 one-half of the potash in the yellow salt, leaving two propor- 
 tions of chromic acid in union with the other half; this process 
 may be expressed thus: — 
 
 f Chromic acid — ^^-^ Bichromate of 
 2 prop, yellow chro- J Chromic acid-^^^^ potash, 
 mate of potash Potash . . . 
 
 [ Potash . . . - 
 
 1 prop! acetic acid . . Acetic acid . — Acetate of potash. 
 
 The solution of yellow chromate being concentrated before the 
 addition of the acetic acid, the bichromate formed has not so 
 
CHROME YELLOW. 
 
 189 
 
 much water as will hold it in solution, and is therefore thrown 
 down as an orange-colored powder ; this is carefully collected, 
 dissolved in water, and crystallized by slow evaporation. 
 
 When the bichromate of potash has been prepared by 
 sulphuric acid, as we stated above, it is very liable to contain 
 sulphate of potash, and that often to a great extent. This 
 salt may be detected by dissolving a small quantity of the 
 chromate in distilled water, adding to it a little pure nitric 
 acid, and then nitrate of barytes, which will giye a white pre- 
 cipitate if a sulphate be present. The solution used in testing 
 should be much diluted. If any chloride of potassium be 
 present, it may be detected by adding a little nitrate of silver 
 to a solution of the chromate, similarly prepared by having a 
 little nitric acid added to it; in this case a white precipitate 
 results. 
 
 Soda has been tried in the preparation of this salt to form 
 a bichromate of soda, which might be equally useful to the 
 dyer, but this base is not used for the reasons already assigned 
 at page 129. 
 
 Chromate of Lead. — The chromates of other bases or 
 metals are obtained by adding solutions of their salts to solu- 
 tions of either the yellow or red chromate of potash. For 
 example, when a salt of lead, e. g. the acetate or nitrate, is 
 added to a solution of bichromate of potash, the chromate of 
 lead is formed and precipitates as a yellow powder, constituting 
 the chrome yellow dye. If this yellow precipitate is digested 
 in hot caustic lye, a basic salt of lead and chromium is formed, 
 having two proportions of lead and one of chromic acid : it is 
 therefore a subchromate of lead. This is a deep orange pre- 
 cipitate, approaching to a scarlet, and constitutes the orange 
 dye. If a little chromate of lead (the grounds of the chrome 
 tub) be dried, and added to some fused nitre in a crucible as 
 long as effervescence and red fumes are observed, and the 
 melted mass is then poured out, there will be at the bottom 
 some subchromate of lead, which may be washed out by 
 w T ater; it is of a* 7 rich vermilion red, far superior to anything 
 we have ever seen as a dye. We would recommend it for 
 trial. 
 
 Chrome Yellow. — The chromate of lead has almost com- 
 pletely superseded the use of vegetable dyestuffs in dyeing 
 yellow, orange, and green upon cotton fabrics. To dye a yellow, 
 the goods are immersed or wrought through a solution of either 
 acetate or nitrate of lead, from which, after being tightly 
 wrung or pressed, they are passed through a solution of bi- 
 chromate of potash, by which the chromate of lead is formed 
 upon and within the fibre. The goods are put several times 
 
190 
 
 CHROME YELLOW. 
 
 through this operation when deep shades are required; or, 
 what is now more generally practised, the lead is added to 
 lime as long as the precipitate formed is redissolved, and the 
 goods are wrought through this solution, and then passed 
 through the bichromate solution ; or the lead may be dissolved 
 in potash or soda. Other qualities of yellow are also obtained 
 by adding hydrochloric acid to the solution of bichromate of 
 potash, distinguished as acid yellow. When dyeing yellows 
 with the acid gait of lead, and passing into the chrome solu- 
 tion, there is a great quantity of chromateof lead formed which 
 is not in the fibre : this precipitates to the bottom, and causes 
 considerable loss. We have already shown that this chromate 
 of lead may be used for making chromic acid ; it is very solu- 
 ble in alkalies, and may be made useful in that way also in the 
 dye-house. When this method of dyeing is practised, there is 
 a liability to inequality of tint. The chromate solution is not 
 •renewed each time, only a little addition of the chrome salt 
 made for each parcel of goods passing through the dye, and 
 therefore there follows an accumulation of free acid in the 
 solution, which reacts upon the color, varying the tint of 
 different lots. So well are these circumstances known in prac- 
 tice, that if yellow of a red tint is required, or what is termed 
 amber, nitrate of lead is used in preference to the acetate in 
 proportion to the depth of redness. This gives free nitric acid 
 in the dye, which acts more than the acetic acid upon the 
 bichromate solution. The same effects are produced by adding 
 a little nitric acid to the chrome solution. The action of the 
 nitrate of lead added to bichromate of potash may be thus 
 stated. Suppose that 100 lbs. of cotton goods are to be dyed 
 yellow, and that they get 165 ounces nitrate of lead, which 
 is all taken up by the cotton: this will require 74 ounces of 
 bichromate of potash. For, taking their equivalents, 
 
 ATM. a f i i ( 1 103 Pb Chromate of lead. 
 
 165 Nitrate of ead \ x , Q ^ Ni ^ f 
 
 one equivalent |£ | N0 » 31 
 
 14 or one-half equi- ( | f 50^ Cr0 3 ' 
 valent of bichro- ■< \ (50| Cr0 3 
 
 mate of potash (J 23|KO.. — ^-Nitrate of potash 
 
 All the lead used is not imbibed by the cotton, therefore much 
 less bichromate is required than that given here, but the action 
 is not altered in relation to the lead really fixed upon the 
 goods. The same reaction takes place when acetate of lead is 
 used, but the free acetic acid does not act so powerfully upon 
 the chromate of lead forming the dye. When subsalts of lead 
 are used, the action is more regular, as no acid is liberated — 
 
CHROME ORANGE. 
 
 191 
 
 hence the decided preference now given to these salts in dye- 
 ing. The action is represented thus: — 
 
 ^ Acetic acid Acetate of potash. 
 
 Subacetate of lead . . . •< Lead ... 
 
 Lead .... 
 ( Potash. 
 
 Bichromate of potash ■< Chromic acid Chromate of lead. 
 
 ( Chromic acid Chromate of lead. 
 
 Were we dyeing 100 lbs. of cotton in different parcels, one 
 after the other, without changing the liquor, the last parcel 
 would have the same chance as the first of being uniform in 
 the color, but not so when each parcel is accumulating free 
 acid, which reddens the color. These formulae also enable us 
 to appreciate the use of alkaline solutions of lead — a practice 
 now often adopted. 
 
 Chrome Greens are dyed in the same manner as the yellow, 
 the goods being previously dyed blue by means of the blue 
 vat. For dyeing green, nitrate of lead is never used, the free 
 nitric acid would destroy the indigo; besides, anything that 
 tends to redden the hue is carefully avoided, so that the goods 
 are not allowed to stand for any time out of the solution of 
 the bichromate ; yet with the greatest amount of care, there is 
 much difficulty in avoiding brown blotches and light parts 
 when acid salts of lead are used ; but there are fewer of these 
 difficulties experienced when the lead is either in a subacetate 
 state, or in the state of an alkaline solution. 
 
 Chrome Orange is obtained by fixing upon the goods the 
 subchromate of lead, as already described. This is effected by 
 dyeing the goods a deep yellow, and passing them through a 
 strong hot alkaline solution, which combines with a portion of 
 the chromic acid, and leaves the subchromate of lead upon the 
 cloth. We have also already alluded to the preparation of the 
 sub or basic salts of lead, and to the proper proportions, and 
 the method of obtaining them, with their use in dyeing. The 
 alkaline solution commonly used for converting the chromate 
 of lead into the subchromate is lime. The reaction taking 
 place may be thus stated : — 
 
 [Lead Subchromate of lead. 
 
 2 Chromate of J Lead .... 
 lead on cloth j Chromic acid' 
 [ Chromic acid- 
 
 Lime Lime Chromate of lime. 
 
 The following receipt will produce a good orange upon a 
 hundred pounds' weight of cotton: — 
 
 Thirty lbs. of brown sugar of lead, and seventeen lbs. of 
 
192 
 
 CHROME AS A MORDANT. 
 
 litharge are put into a boiler with about 12 gallons of water 
 and boiled together for an hour or so, until the litharge is 
 dissolved ; then a quantity of lime, from one to two pounds, is 
 added, any sediment formed is allowed to settle, and the clear 
 fluid drawn off' and put into a tub ; 12 lbs. bichromate of 
 potash are dissolved in another tub. Two other tubs, capable 
 of allowing 10 lbs. of yarn to be wrought in them with free- 
 dom, are rilled, one with water, to which a little of the lead 
 solution is added, and the other with lime-water; 10 lbs. of 
 the yarn (a bundle) is now wrought for some time through the 
 tub containing the lead, wrung out, and put through the lime- 
 water ; a little more lead is added, another bundle is passed 
 through the same tub, renewing the lime-water each time. The 
 whole are passed two or three times through this operation, 
 according to the depth of orange wanted. The bundles are 
 next wrought through a tub of water, to which is added some 
 of the solution of the bichromate of potash, then passed through 
 the lead solution, and again through the chrome. A satu- 
 rated solution of newly slaked lime is brought to the boiling 
 point ; in this the yarn is wrought, either by drawing some off 
 in tubs, or by the most convenient method that circumstances 
 will allow, until the color is changed to a deep orange or 
 scarlet. It is then taken out, passed through another tub 
 filled with boiling water, to which is added a small quantity of 
 solution of soap, soda, and oil ; afterwards, it is wrung out 
 and dried at a high temperature. The raising of the orange, 
 as the hot liming is termed, is the most trying operation. If 
 the lead has not been properly prepared, or if there be any 
 mismanagement in the operation of fixing it upon the fibre, 
 the hot lime will take all the color off, leaving but a red salmon 
 shade. Or if the goods are unequally dyed, the color will 
 come off in parts; and what is still more frequently the case, 
 the chromate of lead being entirely soluble in lime-water at a 
 temperature a little under boiling, if the lime solution is 
 allowed to become too cold, the color will be discharged. The 
 lime-water ought to be at the spring of the boil, and, as we have 
 seen (page 135), the higher the temperature, the less lime is 
 held in solution, consequently less risk of failure. Great care 
 is necessary, for an orange being once wrong, it is very diffi- 
 cult to recover. 
 
 Bichromate of potash has been very extensively used of late 
 as a mordant for a variety of .colors upon woollen, and is 
 entirely superseding several of the old processes for dyeing 
 many of the ordinary shades, which are very tedious in manipu- 
 lation. It is also extensively used for dyeing catechu browns 
 upon cotton. We may mention that working much with solu- 
 
VANADIUM. 
 
 193 
 
 tions of chrome and lead is very injurious to the hands, espe- 
 cially if there be any part of the skin broken, producing often 
 very severe sores; a solution of guttapercha applied over the 
 sore, forming an artificial skin, has the effect of preventing 
 this annoyance. 
 
 Tests for Bichromate of Potash. — Tests for the strength 
 and quality of bichromate of potash may easily be formed, 
 thus: Take pure nitrate of lead, say 165 grains > and dissolve 
 in 200 measures of water; this ought to precipitate 74 grains 
 of bichromate; so that it is merely required to dissolve 74 
 grains of bichromate of potash, and adding the nitrate of lead 
 solution as long as any precipitate takes place : if all the lead 
 is requisite, the chrome is good, but every three graduations 
 of the lead solution left, after precipitating all the chrome, will 
 represent about one per cent, impurity of the bichromate ; or 
 the same method maybe taken as described for lead (page 174). 
 These operations are easy, and may be performed by any prac- 
 tical dyer, although little acquainted with chemical manipula- 
 tions. 
 
 The following is the reaction of salts of oxide of chromium 
 with other substances in solution : — 
 
 Potash and soda • . . . . 
 
 Ammonia 
 
 Carbonates of the alkalies . . 
 Yellow and red prussiates of 
 
 potash 
 
 Solution of galls ...... 
 
 Greenish precipitates solu- 
 ble in excess. 
 Grayish blue precipitate. 
 Light green precipitates. 
 
 No precipitates. 
 Greenish precipitate. 
 
 The reaction of bichromate upon reagents is as follows : — 
 
 Solutions of lead Yellow precipitates, soluble 
 
 in potash. 
 
 Silver salts Bed brown. 
 
 Zinc Forms with these salts a 
 
 double salt, which is 
 brown, and crystallizes. 
 
 Vanadium (V 68.6). 
 
 This metal was discovered in 1830. It is found in nature 
 combined with lead and iron, but is exceedingly rare. Small 
 samples of its oxide, termed Vanadic Acid, were sold at Is. 6d. 
 a grain. It has a strong resemblance to chromium in many 
 of its chemical characters, and combines with oxygen in three 
 proportions: — 
 13 
 
194 
 
 TUNGSTENUM. 
 
 Protoxide =V0. 
 
 Binoxide ..... =V0 2 . 
 Vanadic acid =V0 3 . 
 
 There is no combination of vanadium with an acid corre- 
 sponding to the protoxide, but there are salts corresponding 
 with the binoxide ; these, in solution, produce with 
 
 Ammonia .... Brown precipitate. 
 
 Yellow prussiate of potash . Yellow precipitate. 
 
 Eed prussiate of potash . . Green precipitate. 
 
 Galls ..... Blue-black precipitate. 
 
 Sulphurets of the alkalies . Brown-black precipitate. 
 
 Vanadic acid combines with the alkalies, and forms a variety 
 of colored salts, nearly all soluble in water. All the reactions 
 of the compounds of this metal give strong hopes that, were it 
 found plentifully, it would become a useful substance in the 
 hand of the dyer; although in the mean time, from its price, 
 it is of no importance to him. 
 
 TlJNGSTENUM, OR WOLFRAM (W 92). 
 
 This metal has the appearance of iron, and exists in nature 
 chiefly in combination with lime. It was formerly the dearest 
 metal next to gold and platinum. It combines with oxygen 
 in two proportions : — 
 
 Binoxide of Tungsten, . . . . =¥0 2 , 
 Tungstic acid =W0 3 . 
 
 Binoxide of tungsten is a brown-red powder, which does not 
 dissolve in acids, and there are, therefore, no salts of tungste- 
 num corresponding to this oxide. The oxide passes readily 
 into the state of tungstic acid by combining with more oxygen; 
 and it is in this state that it is found in nature forming a 
 tungstate of lime. By dissolving this mineral in hydrochloric 
 acid, the lime is dissolved, and the tungstic acid remains as a 
 yellowish powder, which combines with alkalies, and forms 
 soluble salts. Acids added to these salts, give yellow precipi- 
 tates, whereas salts of lead, lime, and barium produce white 
 precipitates. 
 
 If tungstic acid is dissolved in the sulphuret of potassium 
 or of sodium, and an acid is added, the tungstenum is precipi- 
 tated in the state of sulphuret, of a deep-brown color, nearly 
 black. 
 
 Tungstate of soda has been proposed for dyeing. Textile 
 fabrics, impregnated with it, are not inflammable. 
 
MOLYBDENUM. 
 
 195 
 
 Molybdenum (Mo 46). 
 
 This metal is obtained in nature combined with sulphur. 
 The ore has much the resemblance of plumbago ; but the metal 
 itself is white, resembling silver, and difficult to fuse. It is 
 not soluble in dilute acids, but dissolves readily in aqua regia. 
 It combines with oxygen in three proportions : — 
 
 Protoxide .... =MoO. 
 
 Peroxide .... = Mo0 2 . 
 
 Molybdicacid .... =Mo0 3 . 
 
 Th§ protoxide is of a black color; is difficultly soluble in 
 acids, giving a black solution, not crystallizable. 
 
 Peroxide of Molybdenum is obtained by digesting molyb- 
 dic acid with hydrochloric acid and copper; the solution has 
 a deep-red color, and by adding to it an excess of ammonia, 
 the copper is dissolved, and the peroxide of molybdenum is 
 precipitated. This oxide dissolves in acids, forming salts which 
 are red when crystallized, owing to the presence of water ; but 
 when rendered anhydrous, they become black. 
 
 Oxalic acid dissolves this oxide, and forms with it a salt 
 which crystallizes in bluish-black crystals. These crystals are 
 soluble in water, and give a red-colored solution, from which, 
 if ammonia be added, a red-brown precipitate is obtained. 
 
 Molybdic Acid is obtained by roasting the native sulphuret 
 in the air until all the sulphur is evolved; the acid remains 
 as a powder. When required pore, this powder is dissolved 
 in ammonia, and the solution is evaporated in order to crystal- 
 lize the acid. The crystals obtained are then submitted to a 
 moderate heat to drive off the ammonia, and the acid remains 
 pure. It is slightly soluble in water, but combines readily 
 with the alkalies, forming salts, which are all soluble in water, 
 and all crystallizable. By adding an acid to the solution of 
 these salts, the molybdic acid is precipitated. They act towards 
 reagents as follows : — 
 
 Salts of lead . . . White precipitate. 
 Nitrate of silver . . White precipitate. 
 Persalts of iron . . . Yellow precipitates. 
 
 The salts formed by dissolving the peroxide in an acid, act 
 towards reagents as follows : — 
 
 Solution of galls . . Yellowish-red precipitate. 
 
 Eed prussiate of potash 1 . , 
 
 ■' i * , i > Brown precipitates. 
 Yellow prussiate oi potash j r r 
 
 Potash and soda . . Brownish-black precipitates. 
 
 Carbonates of the alkalies . Light-brown precipitates. 
 
 Sulphurets of the alkalies . Brownish-yellow precipitates. 
 
196 
 
 TELLURIUM — ARSENIC. 
 
 Similar precipitates may be obtained from the salts of molybdic 
 acid, by adding, along with the reagents, a little hydrochloric 
 acid, to take up the alkali of the salt. 
 
 Tellurium (Te 64.2). 
 
 This is a metal which is found in combination with silver, 
 bismuth, and lead. Its color is silver-white, its structure 
 crystalline and brittle; it volatilizes at a high heat, and burns 
 in air with a blue flame. It combines with oxygen in two 
 proportions, both of which have acid properties : — 
 
 Tellurous acid .... =Te0 2 . 
 Telluric acid .... =Te0 3 . 
 
 Tellurous Acid is a light, white, earthy powder, soluble • 
 in acids, and also in the alkalies, with which it forms salts 
 (tellurites), which are very soluble in water, and easily decom- 
 posed. 
 
 Telluric Acid may be obtained by first fusing tellurous 
 acid with nitre, which gives tellurate of potash ; then, by dis- 
 solving this salt and adding a solution of barytes, there is 
 formed an insoluble tellurate of barytes, which is again decom- 
 posed by digestion in sulphuric acid ; the sulphuric acid takes 
 up the barytes, and the telluric acid remains in solution, and 
 may be afterwards crystallized. A tellurate of soda and potash 
 may be formed by dissolving these alkalies in the acid ; the}?' 
 are soluble in water. 
 
 The action of reagents upon the salts of tellurium is as 
 follows : — 
 
 Alkalies . . . White precipitates, redissolved. 
 Yellow and red prussiate No precipitate. 
 Solution of galls . . Yellowish precipitate. 
 Sulphureted alkalies . Brownish precipitates. 
 
 Arsenic (As 75). 
 
 This metal is very abundantly distributed in nature, and is 
 found in various states of combination. It is chiefly, however, 
 associated with iron, nickel, and cobalt. Arsenic has a gray- 
 steel lustre, is brittle, crystalline, and very easily sublimed, 
 rising in vapor at a heat of about 356°, and is thus easily sepa- 
 rated from its ores. It combines with oxygen in three dif- 
 ferent proportions: First, a grayish oxide, probably suboxide, 
 
ARSENIOUS ACID. 
 
 197 
 
 which forms upon the surface of the metal by exposure to air; 
 and 
 
 Arsenious acid .... =As0 3 . 
 Arsenic acid . . . . =As0 5 . 
 
 Arsenious Acid. — This is plentiful in commerce as white 
 oxide of arsenic; it is a heavy white opaque mass as sublimed, 
 although generally sold in the market as a powder and in 
 crystals. This acid is dissolved by boiling water, in the pro- 
 portion of about 1 part to 10 of water; but on cooling, the 
 solution deposits nearly three-fourths of this quantity. It has 
 little, if any, taste, but is notoriously a deadly poison.* 
 
 It dissolves in hydrochloric acid in much greater quantity 
 than in water, but does not combine with the acid (see Chlo- 
 rine). It is rapidly dissolved in hot solutions of bitartrate of 
 potash, and forms a crystallizable salt. 
 
 It is dissolved also in great quantity by solutions of potash 
 and soda, and also, but not so effectually, by the carbonates of 
 these alkalies. 
 
 This acid, as before mentioned (page 169), is used in the 
 dye-house for dyeing Scheele's green {arsenic sages)] but we 
 are convinced that similar colors might be produced by other 
 means ; and there cannot be a doubt but that any process which 
 would supersede its use would benefit all who are engaged in 
 the preparation of such goods. Common humanity, indeed, 
 dictates its complete abandonment as a dye. Nor is the evil so 
 much in the operations of dyeing, as in those that succeed: 
 persons who have occasion to work with the yarns after they 
 are dyed, suffer more severely than the dyers. The color being 
 merely a precipitate of the arsenite of copper (a most deadly 
 poison) upon the fibre of the yarn, to which it but loosely 
 adheres, it is readily disengaged as dust in the dry state, and in 
 the process of winding, especially, much of it is unavoidably 
 inhaled by the unfortunate operative. The result is, as might 
 be expected, that health is seriously impaired, and not unfre- 
 quently the consequences are fatal. It is, in fact, consistent 
 with our knowledge, that individuals of this class have never 
 
 *The best antidote for arsenic, when taken into the stomach, is newly 
 precipitated peroxide of iron. This can always be obtained in a very few 
 minutes in the dye-house, by adding to the nitrate, or any other /?er-solutions 
 of iron, a little potash or soda ; the iron is immediately precipitated. The 
 precipitate ought first to be washed with water, and then taken in the gelati- 
 nous state. The arsenious acid in the stomach receives oxygen from the 
 peroxide of iron, and is converted into arsenic acid, which combines with the 
 protoxide of iron, which is not poisonous. Should arsenic be taken into the 
 stomach in the state of arsenic acid, protoxide of iron will serve the same 
 purpose as the peroxide, and is obtained by precipitating some copperas, by 
 means of an alkali. 
 
198 
 
 SULPHURETS OF ARSENIC. 
 
 recovered from the effects of winding a quantity of arsenic sage 
 yarn, for which they were paid one shilling ! Warpers also are 
 subjected to the same baneful evil, although in a less degree, 
 and even the weaver is not exempt from it. Altogether, indeed, 
 the injury to the community by the use of this dye outweighs 
 a hundredfold that arising from the unrestricted sale of poisons, 
 against which so loud a protest was lately raised. We are con- 
 vinced, moreover, that it is a gratuitous evil, and that dyers 
 would very soon, under the pressure of a little public opinion, 
 find means of avoiding it, and producing the color innocuously, 
 and of an innocuous character. 
 
 Arsenic Acid. — This acid is made by heating arsenious acid 
 with about its own weight of water, and when at the boiling 
 point adding nitric acid, as long as red fumes are given off: the 
 whole is then evaporated to dryness, to expel any excess of 
 nitric acid that may be present. The heat of the mass, when 
 dry, must not be high, otherwise the arsenic acid will be de- 
 composed. Arsenic acid is milk-white, deliquesces, and is solu- 
 ble in water: its solution having a sour taste, and strong acid 
 reactions. 
 
 When an equivalent of arsenic acid is ignited with an excess 
 of carbonate of soda or potash, a subsalt is formed, which is 
 soluble in water, and easily crystallized. Salts of the alkalies 
 are also formed by adding arsenic acid to hot solutions. These 
 salts crystallize, and their solutions in water give white precipi- 
 tates with the solutions of the earths and their salts. Solu- 
 tions of the salts of lead also give white precipitates ; nitrate of 
 silver a precipitate of a brown color ; and salts of copper pro- 
 duce green precipitates. These salts can all be made available 
 in the dye-house, although, for the reasons above stated, it 
 would be well if substitutes were used. 
 
 Sulphurets of Arsenic. — There are two compouuds of sul- 
 phur and arsenic, which are, or rather were, occasionally used 
 in the dye house. These are — 
 
 The first of these can be prepared by fusing arsenic, or arse- 
 nious acid, with sulphur; it is transparent, and of a fine ruby 
 color. 
 
 The latter may be prepared by adding to a solution of arse- 
 nious acid in hydrochloric acid, a sulphuret of an alkali, either 
 potash or soda; it is precipitated of a rich yellow color, and is 
 much used in painting, under the name of king's yellow. 
 
 Both of these sulphurets are found native. Their principal 
 use in the dye-house was in the blue vat. 
 
 Realgar 
 Orpiment 
 
 = As S 2 . 
 = As S 3 . 
 
ANTIMONY. 
 
 199 
 
 Arsenic combines readily with hydrogen, and forms a gas, 
 arseniureted hydrogen, which is very poisonous. When arsenic 
 is present in any solution from which hydrogen is being given 
 off, arseniureted hydrogen is formed, and therefore care ought 
 to be taken not to breathe any of the gas. Sulphuric acid (see 
 page 98) often contains arsenic. 
 
 Antimony (Sb 129). 
 
 This metal is found in considerable abundance associated 
 with sulphur, which is separated from it by roasting. Anti- 
 mony is a bright and white metal, of a crystalline structure, 
 very brittle, and not oxidized by exposure to the air. It vol- 
 atilizes at a high heat, and oxidizes or burns at a red heat, 
 when exposed to the air ; it then passes off in white fumes. 
 Antimony combines with oxygen in two principal proportions, 
 forming — 
 
 Oxide of antimony =Sb 2 0 3 . 
 
 Antimonic acid ...... =Sb 2 0 5 . 
 
 Oxide of Antimony may be prepared either by sublimation, 
 as already stated, or by precipitation from a solution of any 
 of its salts, by an alkali. 
 
 When the sulphuret of antimony (the common ore) is di- 
 gested in strong hydrochloric acid, the metal dissolves, and 
 forms a chloride of antiinony ; or rather, a sesquichloride, as 
 follows: — 
 
 Sulphuret of antimony { & Z^^tt^' 
 
 Three proportions of 
 
 hydrochloric acid \3C1. ::::: ^Chioride of antimony. 
 
 The clear solution being poured off, and heated to the boil- 
 ing point, carbonate of potash or soda is then added, and the 
 antimony is precipitated in the state of oxide as a white pow- 
 der. Both potash and soda dissolve this oxide. 
 
 Sulphate of Antimony may be prepared by digesting the 
 sulphuret in strong sulphuric acid with the aid of heat; or the 
 metal may be substituted for the sulphuret. 
 
 All the acid salts of antimony are decomposed by aqueous 
 dilution: an insoluble oxychloride is thereby formed and pre- 
 cipitated as a white powder. There are, however, several dou- 
 ble salts of antimony with other substances, which are soluble, 
 and not precipitated by dilution. Thus, when a strong solution 
 of binoxalate of potash is heated, and oxide of antimony added, 
 a salt is formed, which is soluble in water, and from which the 
 
 i 
 
200 
 
 URANIUM. 
 
 antimony is not precipitated by dilution. Again, when oxide 
 of antimony is boiled in water, and tartrate of potash added, 
 a double salt (tartar emetic) is formed, which crystallizes, and 
 is not precipitated by dilution. 
 
 Some chemists recognize an Antimonious Acid, which is 
 obtained by oxidating or acting upon, metallic antimony with 
 nitric acid. It is also formed when sulphate of antimony is 
 roasted. Some doubts exist as to the true nature of this com- 
 pound; it is probably a mixture of oxide of antimony with an- 
 timonic acid (thus Sb 2 0 3 +Sb 2 0 5 ), having the same elements as 
 two proportions of antimonious acid =2Sb 2 0 4 . The combina- 
 tions of this acid have not been studied. 
 
 Antimonic Acid is prepared in the same manner as described 
 for arsenic acid, that is, by acting upon the oxide with nitric 
 acid, and expelling any excess of the acid by heat. Antimonic 
 acid is a pale-yellow powder, not soluble in water, but soluble 
 in potash and soda, with which it forms antimoniates, which, 
 however, are not stable, and are decomposed by almost any 
 other acid or salt. 
 
 The precipitates formed by reagents with salts of antimony 
 are nearly all white, but when a sulphuret of any of the alka- 
 lies is added to a solution of antimony, a beautiful golden yel- 
 low precipitate is formed. 
 
 Uranium (U 60). 
 
 This rare metal is a component of the mineral named pitch- 
 blende, which contains several other metals. Its metallic cha- 
 racteristics have only been recently ascertained; indeed, one of 
 its oxides was, till lately, regarded as an element. It is a white- 
 colored metal very like silver, but is peculiar in being very in- 
 flammable, burning with great brightness at a low red heat. 
 It combines with oxygen in several proportions, but only two 
 of its oxides are soluble in acids, and form corresponding salts, 
 These are the 
 
 Protoxide =U0. 
 
 Peroxide = U 2 0 3 . 
 
 Protoxide of Uranium is obtained by acting upon the min- 
 eral above named, by aqua regia, and separating it from the 
 various other metals with which it is associated, by precipita- 
 tion. When a solution of uranium in an acid is precipitated 
 by an alkali, and the alkali is well washed out, the remainder 
 is in the state of protoxide. This oxide dissolves with diffi- 
 culty in hydrochloric acid, but more freely in dilute sulphuric 
 
CEKIUM. 
 
 201 
 
 acid with the aid of heat, and gives a green solution, which 
 yields similarly colored crystals. It is very soluble in nitric 
 acid, forming a nitrate. These salts give the following reac- 
 tions: — 
 
 Carbonates of the alkalies . . Greenish precipitates. 
 Yellow prussiate of potash . . Eeddish-brown precipitate. 
 Eed prussiate of potash . . . Eeddish-brown precipitate, 
 
 after a time. 
 
 Sulphurets of the alkalies . . Black precipitates. 
 
 Peroxide of Uranium is obtained by precipitation from a 
 solution of the mineral by means of an alkali; the precipitate 
 is collected, but the alkali is not washed out, and the residue is 
 then exposed to a red heat; the presence of the alkali prevents 
 the metal, which is present as a peroxide, from passing into 
 the protoxide state. When thus treated the oxide is stable. 
 Ammonia, however, will not serve as the precipitant in this 
 case, as, on account of its volatile nature, it would be dissipated 
 by the heat to which the precipitate must be exposed. 
 
 The peroxide of uranium has a beautiful yellow color, and 
 is soluble in all the acids, and forms persalts. The solutions 
 of these salts act towards reagents as follows: — 
 
 Alkalies and their carbonates . . Yellow precipitates. 
 Yellow prussiate of potash .... Eeddish-brown precipitate. 
 
 Eed prussiate of potash No precipitate. 
 
 Solution of galls Dark brown precipitate. 
 
 Sulphurets of the alkalies .... Brown precipitates. 
 
 It may be inferred from these reactions that, could this metal 
 be obtained in sufficient quantity, it would form a valuable ad- 
 dition to the dyer's coloring matters. At present, however, it 
 is too scarce to be regarded as of any practical importance. 
 
 This metal is obtained in small quantities from several mine- 
 rals, found chiefly in Sweden and Greenland. These are acted 
 upon by aqua regia, and the metal is separated by reagents. 
 Hitherto, it has been obtained only as a powder of a brownish- 
 black color, which is rapidly decomposed in water. With oxy- 
 gen it forms 
 
 Alkalies 
 
 Brownish precipitates. 
 
 Cerium (Ce 47). 
 
 Protoxide 
 Peroxide 
 
 = Ce O. 
 
 = Ce 2 0 3 . 
 
202 
 
 MERCURY. 
 
 The oxides and salts of cerium are mostly white, but have not 
 been subjected to any close investigation. Eeagents generally 
 give white precipitates with solutions of the salts. 
 
 Mercury (Hg 100). 
 
 This metal is found abundantly both in the metallic state and 
 in combination with sulphur, forming the mineral cinnabar, 
 from which the metal is distilled, by heating it with iron and 
 lime. Mercury at ordinary temperatures is liquid; hence its 
 popular name of quicksilver ; it has a high metallic lustre, be- 
 comes solid at 40° below zero, and gaseous at 662°. It com- 
 bines with oxygen in two well-known proportions: — 
 
 Suboxide = Hg 2 0. 
 
 Protoxide = Hg O. 
 
 Suboxide of Mercury is a black powder, and is obtained 
 by precipitation from a cold solution of subnitrate of mercury 
 by potash or soda. It dissolves in acids, and forms a series of 
 salts of great use in medicine. The common calomel of the 
 druggists is a subchloride of mercury = Hg 2 CI. The subsalts 
 of mercury give the following reactions: — 
 
 Alkalies 
 
 Carbonates of the alkalies . . 
 
 Yellow prussiate of potash . 
 Eed prussiate of potash . . 
 
 Solution of galls 
 
 Bichromate of potash . . . 
 Sulphurets of the alkalies . . 
 
 Black precipitates. 
 
 White precipitates, which be- 
 come black by heating. 
 White precipitate. 
 Reddish-brown precipitate. 
 Light yellow precipitate. 
 Red precipitate. 
 Black precipitates. 
 
 Protoxide of Mercury, Peroxide of Mercury. — This 
 oxide is obtained by heating mercury in contact with oxygen, 
 or by exposing nitrate of mercury to heat until all the acid is 
 expelled. Its color is a deep red, and hence it is known in 
 commerce as red precipitate. 
 
 When mercury is acted upon by an acid, persalts are gene- 
 rally formed. These salts may also be formed by dissolving 
 the red oxide in the acids. Thus the perchloride (corrosive sub- 
 limate) may be prepared by dissolving the red oxide in hydro- 
 chloric acid. There are a great variety of salts of mercury, 
 nearly all poisonous, and all less or more used in medicine. 
 None of them are used in dyeing, but some are useful as tests. 
 The following are their reactions with other substances: — 
 
SILVER. 
 
 203 
 
 Potash and soda Yellow precipitates. 
 
 Ammonia White precipitate. 
 
 Carbonates of the alkalies. . Reddish-brown precipitate. 
 
 Carbonate of ammonia . . . . White precipitate. 
 
 Yellow prussiate of potash . White precipitate. 
 
 Eed prussiate of potash . . . Yellow precipitate. 
 
 Solution of galls No precipitate. 
 
 Iodide of potassium Red precipitate. 
 
 Bichromate of potash .... Red precipitate. 
 Sulphurets of the alkalies . . Black precipitates. 
 
 These colors are not generally permanent upon cotton, but 
 are destroyed when exposed to a moderate heat. 
 
 Silver (Ag 108). 
 
 This metal is found in considerable abundance in nature, and 
 is very widely diffused; it is generally in combination with 
 sulphur, along with other metals, particularly with lead. It is 
 obtained from the lead ores of this country, and is extracted 
 from them by cupellation, as was described under the head of 
 Litharge (page 170). It is also extracted from its sulphurets, 
 and from some other ores which are found abroad, from which 
 the greater quantity of the silver is obtained, by roasting the 
 ore, after mixing with it a quantity of common salt, which 
 converts the silver into a chloride. The ore is next put into 
 large barrels with water and scraps of metallic iron and mer- 
 cury, and the barrels are kept revolving, in order thoroughly 
 to mix their contents. The iron decomposes the chloride of 
 silver, and becomes a chloride of iron, and the mercury takes 
 the liberated silver, and forms with it an amalgam. The reac- 
 tions may be thus represented: — 
 
 Chloride of silver 
 
 f Ag ; Amalgam of silver. 
 
 (01. 
 
 Mercury . . . 
 
 Iron Fe. Chloride of iron, soluble. 
 
 The amalgam is collected and subjected to a high heat in a re- 
 tort; the mercury is thereby distilled over, and the silver re- 
 mains behind. 
 
 Silver is the whitest of all the metals; it is also highly duc- 
 tile and malleable, and does not combine with oxygen by ex- 
 posure to the air, but is very soon tarnished by the fumes of 
 sulphur, which always exist to some extent in localities where 
 coal is burned. Silver combines with oxygen in three propor- 
 tions: — 
 
204 
 
 SILVER. 
 
 Suboxide 
 Protoxide 
 Peroxide 
 
 = Ag 2 0. 
 = Ag O. 
 
 The first and last of these oxides are little known; the prot- 
 oxide is of the most importance, and is obtained as a deep 
 brown powder, by adding an alkali to the solution of any 
 soluble salt of silver. This oxide dissolves in acids, and forms 
 protosalts. 
 
 Nitrate of Silver. — Nitric acid, diluted, dissolves silver by 
 the aid of heat with great ease; and the nitrate formed is the 
 salt commonly used in the laboratories. It is very corrosive, 
 blackens the skin, and constitutes the permanent marking-ink 
 for linen, which, by the way, may be easily obliterated by dip- 
 ping the cloth in chlorine water. The chlorine converts the 
 silver into a chloride, which is washed out by passing the cloth 
 through liquid ammonia. 
 
 Sulphate of Silver. — Silver is dissolved by hot sulphuric 
 acid, and forms a sulphate of silver. This salt crystallizes, and 
 is very corrosive, but it is little used. 
 
 The attraction of silver for chlorine is so great that hydro- 
 chloric acid, or any chloride, added to a salt of silver, instantly 
 decomposes it, and converts the silver into an insoluble chlo- 
 ride. Hence it is that chlorides are the best tests for silver, 
 and that silver is in turn the best test for chlorine. 
 
 Oxide of silver is soluble in acetic acid, and many of the 
 milder acids; and several of its salts are now extensively used 
 for photographic purposes. 
 
 Chloride of silver is soluble in hyposulphite of soda, forming 
 a salt, which is also much used in obtaining pictures by means 
 of light; the study of the action of light upon these salts is 
 indeed well worthy the attention of dyers (page 29), as the 
 phenomena are highly suggestive of practical application. 
 
 When experimenting with salts of silver, it is, of course, im- 
 portant that none of the metal be lost; and it may be all re- 
 covered by converting it into chloride, or evaporating the solu- 
 tion in the case of hyposulphites, and when dry, mixing with 
 three times its weight of dry carbonate of potash, putting this 
 into a crucible, and fusing for fifteen minutes: when the cruci- 
 ble cools, the metallic silver will be found as a button of metal 
 at the bottom. 
 
 The salts of silver have the following reactions with other 
 substances: — 
 
GOLD. 
 
 205 
 
 Potash and soda 
 Ammonia . . 
 
 Carbonates of the alkalies , 
 Yellow prussiate of potash 
 Eed prussiate of potash . 
 Solution of galls . . . 
 Bichromate of potash 
 Sulphurets of the alkalies 
 
 Brown precipitates. 
 
 Brown precipitate, very soluble 
 
 in excess. 
 White precipitates. 
 
 White precipitate. 
 
 Red-brown precipitate. 
 
 No precipitate. 
 
 Crimson-red precipitate. 
 
 Black precipitates. 
 
 The necessary expense of this metal prevents its introduction 
 to the dye-house; and we are afraid that its property of be- 
 coming black by light would destroy its general usefulness, 
 even could it be had sufficiently cheap. 
 
 Gold (Au 197 or 98.5). 
 
 This metal is commonly found in the metallic state, and nearly 
 pure, but sometimes it is associated with other metals; it is ex- 
 tensively diffused through nature. When it is found along 
 with silver, the ore is treated in the same way as the other ores 
 of silver, and the two metals are obtained together in alloy ; 
 but when the metal is diffused through the rock, in the metal- 
 lic state, the rock is stamped to fine powder, and then submit- 
 ted to a current of water, which carries away the light earthy 
 portion, and the gold falls to the bottom from its superior 
 weight. This residuum is mixed with metallic mercury, to form 
 an amalgam with the gold, which is afterwards distilled in the 
 same manner as was described for silver. 
 
 Gold and silver are separated by subjecting the alloy to nitric 
 or strong sulphuric acid, which dissolves the silver and leaves 
 the gold. The silver is precipitated as a chloride, and reduced, 
 by fusion with carbonate of potash, an operation which is termed 
 parting. 
 
 Gold is the only yellow metal known; it is the most ductile 
 as well as the most malleable of the metals, and does not oxi- 
 date or tarnish by exposure to the air, which gives it an intrin- 
 sic value over most of the other metals. It does not dissolve 
 in any single acid, but is readily acted upon by aqua regia, 
 forming a perchloride. It combines with oxygen in two pro- 
 portions: — 
 
 Suboxide =Au 2 O. 
 
 Peroxide = Au 2 . 0 3 . 
 
 The first of these oxides is obtained by adding a solution of 
 potash to subchloride of gold: it is a green powder. 
 
206 
 
 PLATINUM. 
 
 The peroxide is obtained by precipitating the solution of gold 
 in aqua regia by magnesia, and washing the precipitate by a 
 little nitric acid. This oxide is of a brown color. 
 
 Subchloride of Gold is prepared by evaporating a solution 
 of gold in aqua regia to dryness, and heating the residue to 
 about 400°, until all smell of»chlorine has ceased, stirring all 
 the while. The product is the subchloride, and is decomposed 
 by water. 
 
 Perchloride of Gold. — This is the salt obtained by dis- 
 solving the metal in aqua regia; but which may be had purer 
 by dissolving the peroxide in hydrochloric acid. Thus: — 
 
 Peroxide of gold . . { £ u ; - Perchloride of gold 
 
 ( 3C 
 
 3 Hydrochloric acid ^ g Water _ 
 
 This salt is yellow, but when it touches the skin it dyes it of 
 a deep purple. Its reactions are as follows : — 
 
 Potash and soda . . . No precipitate. 
 Ammonia .... Yellow precipitate. 
 Oxalic acid .... Dark-greeri precipitate. 
 Yellow prussiate of potash . Light-green precipitate. 
 Eed prussiate of potash . No precipitate. 
 Protosalts of iron . . . Brown (metallic gold) pre- 
 cipitates. 
 
 Protosalts of tin . . Purple precipitates. 
 
 Solution of galls . . . Black precipitate, which be« 
 
 comes brown (metallic gold) 
 
 Salts of this metal, on account of their expense, can only 
 be used as reagents in the laboratory, not in manufacturing 
 operations. 
 
 Platinum (Pt 98.7). 
 
 This metal is found in a native state in the debris of rocks 
 belonging to the earliest igneous formation. It was first dis- 
 covered in the auriferous sands of some rivers in America, but 
 is now found in various localities; and comes principally from 
 Siberia. Platinum is a white metal, very ductile, and also malle- 
 able ; it is the densest metal known, and is not acted upon by 
 exposure to the air, nor oxidized by heat. No single acid 
 affects it, on which account it is exceedingly useful in many 
 chemical processes. Aqua regia dissolves it with the aid of 
 heat, and forms with it a perchloride. It combines with oxygen 
 in two proportions: — 
 
PALLADIUM. 
 
 207 
 
 Protoxide =Pt 0. 
 
 Peroxide =Pt 0 2 . 
 
 The protoxide is obtained by digesting the protochloride in 
 potash ; it is a black powder, soluble in excess of potash, yield- 
 ing a green solution, from which the platinum may be precipi- 
 tated. 
 
 The protochloride is obtained in the same manner as the 
 protochloride of gold ; it is a greenish powder, slightly soluble 
 in strong hydrochloric acid. 
 
 The peroxide of platinum is obtained by adding to a solution 
 of sulphate of platinum some nitrate of barytes; the sulphuric 
 acid is precipitated, and nitrate of platinum is formed, which 
 remains in solution. By adding to this solution a little soda, 
 peroxide of platinum is precipitated as a reddish-brown powder. 
 This oxide dissolves in acids, forming salts, which are mostly 
 of a brownish-red color, and has a strong attraction for the 
 earthy bases. 
 
 The sulphate is prepared by adding to a solution of plati- 
 num in aqua regia, drop by drop, a solution of sulphuret of 
 potassium, which forms a bisulphuret of platinum; by expo- 
 sure to the air, the sulphur extracts oxygen, and becomes 
 sulphuric acid, which combines with the metal. 
 
 Bichloride of platinum is the salt formed when the metal is 
 dissolved in aqua regia; it has a deep-red color. This salt 
 combines with chloride of potassium, and forms with it a 
 double salt, which crystallizes in beautiful reddish-yellow crys- 
 tals. The persalts of platinum are all more or less red in color, 
 and have the following reactions with other substances: — 
 
 Potash, soda, ammonia, and ) y n . . 
 
 their carbonates . . . j r r 
 
 Yellow prussiate of potash Yellow precipitate. 
 Bed prussiate of potash . Yellow precipitate. 
 Solution of galls .... No precipitate. 
 
 " A reddish brown colored solu- 
 tion, the tin being rendered 
 Protochloride of tin . . . -{ a perchloride, the platinum 
 
 a protochloride ; but there is 
 no precipitate. 
 
 Sulphurets of the alkalies Beddish-brown precipitates. 
 
 Palladium (Pd 53.3). 
 
 This metal is found associated with platinum ; its appearance 
 is very similar, except that it has a slightly reddish tint, and 
 
208 
 
 IRIDIUM. 
 
 only about half the density. It is nearly as infusible, but its 
 surface slightly tarnishes by exposure to air, and it is soluble 
 in nitric acid. Like platinum, it combines with oxygen in two 
 proportions : — 
 
 Protoxide =Pd 0. 
 
 Peroxide =Pd 0 2 . 
 
 The protoxide is a dark-brown powder, and is obtained by 
 dissolving the metal in nitric acid, evaporating to dryness, and 
 heating the residue to drive off the acid ; or it is precipitated 
 from the acid by an alkaline solution. 
 
 The protochloride of palladium is formed by dissolving the 
 metal in hydrochloric acid, to which a few drops of nitric acid 
 have been added. The former acid acts upon the metal slowly 
 when alone, but this addition quickens the action. The solution 
 is evaporated to dryness, to expel any excess of acid, and 
 yields a compound of a dark-brown color, which is protochlo- 
 ride. This salt combines with chloride of potassium and 
 sodium, and forms double salts, which deposit yellow-colored 
 crystals from their solutions. 
 
 The peroxide of palladium is obtained by first dissolving the 
 metal in strong aqua regia ; this gives a solution of a dark- 
 brown color, which is a bichloride of the metal. To this solution 
 is added, gradually, either potash or soda, which precipitates 
 the metal as a hydrated peroxide of a reddish-brown color. 
 The salts corresponding to the peroxide are little known. 
 Solutions of the protosalts of palladium act towards reagents 
 as under: — 
 
 Brownish precipitates. 
 No precipitate. 
 Brown precipitates. 
 
 No precipitates. 
 
 Black precipitate. 
 Brown precipitate. 
 Black precipitates. 
 
 Iridium (Ir 99). 
 
 This metal is found combined with platinum, which, like 
 palladium, it also resembles in appearance. It is more infusi- 
 ble than platinum, and, if pure, resists the action of all the 
 acids; but when alloyed with platinum, it is soluble in aqua 
 regia. It is known to combine with oxygen in four propor- 
 tions, forming — 
 
 Potash and soda 
 Ammonia . 
 
 Carbonates of potash and soda . 
 Yellow and red prussiates of ) 
 potash j 
 Protochloride of tin . 
 Phosphate of soda 
 Sulphurets of the alkalies . 
 
OSMIUM— RHODIUM. 
 
 209 
 
 Protoxide =IrO. 
 
 Sesquioxide ..... =lr 2 0 3 . 
 
 Binoxide =Ir 0 2 . 
 
 Peroxide = Ir 0 3 . 
 
 To all of which there are corresponding chlorides known. The 
 salts of this metal are mostly of a rose color, and insoluble, or 
 nearly so, in water. They are of no practical value. 
 
 Osmium (Os 99.6). 
 
 This metal is always found associated with iridium in pla- 
 tinum, and is obtained in a pulverulent state. It dissolves, 
 when alone, in strong nitric acid' and aqua regia — in both cases 
 forming osmic acid. It combines with oxygen in five propor- 
 tions: — 
 
 Protoxide . . . . . =OsO. 
 
 Sesquioxide ..... =Os 2 0 3 . 
 
 Binoxide. ..... =Os0 2 . 
 
 Peroxide =Os0 3 . 
 Osmic acid . . . . . =OsO,. 
 
 These oxides are nearly all brown. There are also correspond- 
 ing chlorides, which are generally colored. 
 
 Ehodium (E 52.2). 
 
 This is another metal found alloyed with platinum, which 
 it resembles in appearance, but is brittle and hard. If pure, 
 it is not acted upon by any of the acids, but when alloyed with 
 another metal, as with platinum, it readily dissolves in aqua 
 regia. Soda precipitates both metals from this solution ; but 
 the platinum precipitate is soluble in alcohol, and is thus easily 
 separated. The rhodium in this state is of a beautiful rose 
 color, and combines with oxygen in two proportions: — 
 
 Protoxide . . . . . =EO. 
 Peroxide ...... = E 2 0 3 . 
 
 The protoxide has not been isolated ; the peroxide is a black 
 powder. The salts are all less or more colored, and generally 
 give colored precipitates with reagents. Ehodium has been 
 introduced into the arts on account of its giving great hard- 
 ness to metals alloyed with it. It is used for tipping metallic 
 (gold and silver) writing pens, &c. 
 14 
 
 4 
 
210 
 
 LANTHANIUM. 
 
 Lanthanium (La 48). 
 
 This metal has been but recently discovered in a mineral 
 from which cerium is obtained. Its oxide has a brick-red color, 
 and dissolves ip acids, giving red-colored salts. 
 
 Along with this metal another has been detected by the same 
 discoverer ; it is named Didymium, and very much resembles 
 Lanthanium in its chemical properties. 
 
 Within these few years, discoveries of several other metals 
 have been announced ; these are all of course rare, and their 
 properties have not yet undergone any very extensive exami- 
 nation. Their names are 
 
 Erbium — Niobium — Pelopium — Ruthenium — Terbium. 
 
 Some of these may yet be found to be peculiar combinations of 
 other known metals, but until that is proved, we must look upon 
 them as metallic elements. 
 
 In the preceding sketch of the elements, we have treated 
 very briefly all those which have not yet had any practical ap- 
 plication to the art of dyeing, and also those that are rare and 
 expensive. Of those elements, we have noticed merely the 
 features and reactions which seemed to us best calculated to 
 attract attention, or which might suggest experiments, with a 
 view to their application in the trade. And although many of 
 the metallic elements, which give indications of available pro- 
 perties, are at present too rare to be employed, yet we know 
 not how soon the rarest of them may be discovered in abun- 
 dance; and it is a law, quite as certain as gravitation itself, that 
 if a demand be created, exertion will follow to satisfy it. When 
 chromium was first discovered, it was considered a rare metal, 
 but, as the demand grew, other ores were found to contain it in 
 great abundance, and so it may be with some of those metals 
 now considered the most rare and the most unlikely ever to be- 
 come abundant. ^ q. ~ Vb^^<jLi>4A*vvv * 
 
I 
 
 211 
 
 TEXTILE FIBRES. 
 
 As the processes, the mordants, and the coloring substances 
 employed in dyeing often vary with the nature of the fabric 
 or stuff to be dyed, it is necessary to examine briefly the corn- 
 position, nature, and properties of the textile fibres. 
 
 These fibres are generally divided into two classes : the vege- 
 table,' and the animal. 
 
 The first class, among quite a variety of substances, com- 
 prises cotton, flax, and hemp, which are mostly composed of 
 lignine. 
 
 The second class, not so numerous, contains silk and wool. 
 
 Cotton. — This substance (Gossypium) forms the filaments 
 which envelope the seeds of plants and trees belonging to the 
 botanical family of Malvaceae, and growing in many parts of 
 the globe, in Northern and Central America, Brazil, Egypt, 
 Persia, India, &c. 
 
 There are a great many varieties, distinguished by the 
 length of their staple, their fineness, and their color. 
 
 Cotton is white, yellow, or reddish. The composition of the 
 coloring matter is not entirely known; it is associated to some 
 pectine and resinous substances, which can be removed by 
 treatment with diluted alkaline solutions. The long staple 
 cotton is generally finer, more elastic, and stronger, than the 
 short staple. 
 
 Viewed under the microscope, cotton appears like a tube, 
 which is the more flattened and twisted as the fruit was more 
 ripe at the time of the gathering of the crop. Unripe and 
 desiccated cotton is also flattened, but the tubes appear split 
 throughout their length. This kind of cotton is sometimes 
 called " dead cotton." 
 
 Flax. — This plant (Linum usitatissimum), of annual growth, 
 had its birth in Central Asia, and has been naturalized in near- 
 ly every civilized country. Several varieties are cultivated, 
 and are distinguished by the difference in coarseness of their 
 fibres. The finest qualities are gathered four or five weeks be- 
 fore the ripening of the seeds. 
 
 The analysis of the flax plant desiccated at 212° Fah., shows 
 95 per cent, of organic matter, and 5 per cent, of mineral sub- 
 stances, composed of potassa, soda, lime, and phosphoric acid. 
 Irish flax contains much silica ; that of Holland and Belgium 
 scarcely any. 
 
212 
 
 TEXTILE FIBRES. 
 
 Its fibres are agglutinated by a mixture of resin, vegetable 
 wax, gum, pectine, sugar, albuminoid and nitrogenized sub- 
 stances, &c, which it is necessary to remove by a kind of 
 spontaneous fermentation in water. It is important that the 
 water should be free from calcareous and ferruginous sub- 
 stances. By fermentation, the foreign matters are destroyed 
 and dissolved, with the evolution of ill-smelling gases. 
 
 This process, which is tedious and noxious, if made in the 
 neighborhood of habitations, can be effected much more rapid- 
 ly (in 48 hours) in vats with tepid water. There is also an 
 advantage in the quality and quantity of the products. 
 
 The fibre of flax is composed of a series of hollow, cylin- 
 drical, and rigid tubes, whose surface is quite smooth, and 
 shows some black spots. 
 
 Hemp. — This plant (Cannabis sativa) does not bear on the 
 same stem the male and female flowers. The male sterns are 
 slender, and become ripe sooner than the female ones. 
 
 There is a great analogy (not for botanists, however), be- 
 tween hemp and flax. The process of culture, fermentation, 
 and mode of treatment are quite the same. But the fibres of 
 hemp are twice as coarse as those of flax, and its tubes are 
 accompanied at their junction with small filaments. 
 
 Silk. — This animal fibre is the fine and strong thread secre- 
 ted by the mouth of the silkworm (bombix) when building its 
 cocoon. The silk thread is formed of two filaments exuded 
 from two orifices near the mouth of the worm, and which 
 become agglutinated as soon as formed. 
 
 Silk, viewed under the microscope, is an exceedingly fine 
 tube, which is, not twisted like cotton, and is not divided into 
 compartments like flax. 
 
 The exterior of the silk fibre proper is covered with an 
 organic substance, which may be dissolved by an alkaline solu- 
 tion, while above this are other substances soluble in water. 
 This kind of varnish contains nitrogenized matters, a sort of 
 wax, and a yellow pigment. 
 
 Silk differs from wool by the absence of sulphur; and from 
 the vegetable fibres because it contains nitrogen. 
 
 Wool, or the fur of sheep, goats, &c, appears under the 
 microscope like a series of thimbles, inserted one into another, 
 and covered with curved filaments. The fibre is coarser, and 
 more or less wiry according to the nature of the sheep. It 
 contains also a canal filled with a liquid, which is sometimes 
 colored. 
 
 Wool is covered with a great quantity of fatty substances, 
 some of them forming a kind of potassa soap, soluble in water, 
 while the others have to be removed by alkaline solution. 
 
 / 
 
TEXTILE FIBRES. 
 
 213 
 
 Deprived of its impurities, wool is a compound of oxygen, hy- 
 drogen, nitrogen, and sulphur. 
 
 • Generalities on Textile Fibres— It is often necessary 
 to distinguish textile fibres, one from the other; we now give 
 some examples. 
 
 A boiling solution of caustic potassa, into which threads of 
 cotton and flax have been steeped during two minutes, gives a 
 dark yellow coloration to flax, while cotton is white or slightly 
 yellow. 
 
 Mr. Mercer, by passing cotton fabrics through cold and con- 
 centrated alkaline solutions, then washing in water, passing into 
 diluted sulphuric acid, and finally rinsing, obtained tissues, 
 which had contracted in every direction, and were much 
 stronger than before. At the same time they absorbed more 
 coloring matter and were dyed more evenly. 
 
 We distinguish wool from cotton, flax, and hemp, by boiling 
 a sample of the suspected mixture in a solution of caustic soda, 
 (8° B.), during two hours. If all is wool, all will be dissolved, 
 the vegetable substances resisting the operation. 
 
 Nitric acid colors wool yellow, after exposure of a few 
 minutes to a moderate temperature; cotton remains white. 
 
 The bichloride of tin, with the help of heat, will blacken 
 cotton and flax, while wool is not affected. 
 
 Boiling and weak muriatic acid dissolves cotton easily, and 
 does not attack wool. 
 
 A mixture of wool and silk is detected by a solution of 
 oxide of lead in caustic soda, which colors the wool brown, 
 and has no action on the silk. 
 
 These reactions require that the samples should not be dyed; 
 if they are colored, it will be necessary to remove the color 
 by successive treatments with acids and alkalies. 
 
 Cold nitric acid dissolves silk, while wool remains unaffected. 
 
 Cotton, flax, and hemp, are easily soluble in a cupro- 
 ammoniacal liquor, made by placing in contact with the air 
 aqua ammonia and copper turnings, and which appears to be 
 a basic nitrate of copper and ammonia.* 
 
 Textile fibres plunged into a solution of alloxane, then wrung 
 out and dried, have acquired the following shades: — 
 
 Wool — a dark red purple (amaranth); 
 
 Silk — a light pink yellow; 
 
 Cotton and Flax — a light , yellow tinge, which is easily re- 
 moved by washing. 
 
 * Silk is also affected by this solution, but more slowly than the vegetable 
 fibres. 
 
214 
 
 MORDANTS. 
 
 If the various coloring matters used in dyeing had an affinity 
 for the fibre in its natural state, the process would be very sim- 
 ple ; it would only be necessary to make a solution of the dye- 
 drug, and immerse the goods in it to insure their being dyed. 
 But so far from this being the case, if we except indigo and 
 safflower, there is scarcely a dyestuff that imparts its own color 
 to goods; nay, the greater part of the dye drugs used have so 
 weak an affinity, for cotton goods especially, that they impart 
 no color sufficiently permanent to deserve the name of a dye. 
 The cause of this is obvious. If, for example, we take a decoc- 
 tion of logwood, the coloring matter is held in solution by the 
 water ; by putting a quantity of cotton into this solution the 
 fibres become filled with the colored solution, but if the cotton 
 has no power to render that coloring matter insoluble within 
 its fibres, it is plain that, by taking out the cotton and putting 
 it into water, the coloring matter within it will be diffused in 
 the water ; in other words, the dye having no attraction for the 
 fibre, is washed out. This primary want of affinity makes dye- 
 ing sufficiently intricate, and renders it more dependent upon 
 science; indeed, it is only by the nicest arrangement of a few 
 chemical laws, that the dyer is enabled to turn to advantage 
 the various coloring matters of which he is in possession. 
 When the dyer finds that there is no affinity between the goods 
 and any coloring substance which is put into his possession, he 
 endeavors to find a third substance, which has a mutual attrac- 
 tion for the cloth and coloring matter, so that by combining 
 this substance with the cloth, and then- passing the cloth through 
 the dyeing solution ; the coloring matter combines with the sub- 
 stance which is upon the goods, and constitutes a dye. This 
 third substance used, which acts as a mediator, combining two 
 inimical bodies, is termed a mordant, from the French mordre, 
 to bite, from an idea which the old dyers had that these sub- 
 stances bit or opened a passage into the fibres of the cloth, 
 giving access to the color. And although the theory of their 
 action is now changed, the term is still continued, and perhaps 
 farther investigation will prove the term applicable. 
 
 All the mordants, with one or two exceptions, are found 
 among the metallic oxides. It may be supposed from this that 
 as metals are the most numerous class of elements, mordants 
 are also very numerous ; it is not so, however. In order that 
 
MORDANTS. 
 
 215 
 
 the substance may act as a mordant, it must possess certain 
 properties ; it must have an attraction for the coloring matter, 
 so as to form with it an insoluble colored compound; and it 
 must be held easily in solution. It may also have an affinity 
 for the fibre, a tendency to unite with it ; but this property is 
 not essentially necessary ; only the first two properties are so, 
 and they limit the mordants almost wholly to what are termed 
 the insoluble bases — that is, substances which are not by them- 
 selves soluble in water. 
 
 The bases or oxides which are in general use as mordants, 
 and which appear to succeed best, are alumina, and the oxides 
 of tift and iron ; the first two are colorless, and the peroxide of 
 the latter is a light brown, and imparts to white goods a buff or 
 nankeen color, which in many cases affects to a considerable 
 extent the color of the cloth, a circumstance which must also 
 be attended to by the dyer. Indeed, the principal part of all 
 dyeing operations is the proper choice and application of mor- 
 dants ; there being a chemical union between them and the 
 coloring matter a new substance is formed, not only differing 
 in properties, but differing in color, from any of the originals; 
 consequently a very little alteration in the strength or quality of 
 a mordant gives a decided alteration in the shade of color. 
 However, it gives the dyer a much wider field for variety of 
 shades; and at the same time a less number of coloring sub- 
 stances are required; as, for example, logwood alone gives no 
 color to cotton worthy the name of a dye ; yet by the judicious 
 application of a few different kinds of mordants, all the shades, 
 from a French white to a violet, from a lavender to a purple, 
 from a blue to a lilac, and from a slate to a black, are obtained 
 from this substance. 
 
 Before any chemical union takes place between bodies, they 
 must not only be in contact, but they must be reduced to their 
 ultimate molecules ; hence, mordants that are insoluble of them : 
 selves must be dissolved in some appropriate menstrua before 
 their particles can enter the fibres of the goods, or combine with 
 the coloring matter. In doing this, the- dyer must attend to 
 the degree of affinity between the solvent and the mordant, to 
 determine what force it will exert against the mordant com- 
 bining with the fibres of the cloth, should there exist an affinity 
 between them, otherwise a powerful mordant may be weakened 
 by the attraction of its solvent ; as, for example, common alum, 
 even though much concentrated, is but a weak mordant for 
 cotton goods, owing to the great attraction between the sul- 
 phuric acid and the alumina. But if acetic acid, which has 
 comparatively a weak affinity for the alumina, be substituted 
 for the sulphuric acid, it becomes a very powerful mordant. 
 
216 
 
 MORDANTS. 
 
 From these things having to be attended to, the dyer has many 
 beautiful illustrations of the relative attraction of different sub- 
 stances for each other. In some cases, the attractions are so 
 nicely balanced that the mordant and coloring matter may be 
 kept mixed, and the goods, when immersed in this solution, 
 having a kind of reciprocal affinity, only receive their share, 
 and do not extract the coloring matter from the solvent, but the 
 depth of color upon the cloth corresponds with the color of the 
 solution. In other cases, the attraction between the mordant 
 and coloring matter is so powerful, that, if the least quantity of 
 the mordant solution be upon the cloth when put into the dye, 
 it seizes the coloring matter, which is instantly precipitated or 
 rendered insoluble, and therefore unfit to combine with the 
 goods, and what coloring matter may have combined with the 
 cloth before being all precipitated, will be uneven ; that is, the 
 resulting color will be light and dark. From these circum- 
 stances, the close alliance of the art of dyeing to the science of 
 chemistry, is evident; but an individual from experience may 
 know these effects, and, though ignorant of the cause, may often 
 guard against their consequences ; knowledge, however, pro- 
 cured only by routine practice, is purchased at a very great cost, 
 and attended with many unpleasant circumstances. In cases 
 where the base has no affinity for the fibre, there exists the same 
 difficulty as with the coloring matter, the fibre being filled with 
 the solution of the base ; should the goods so filled be passed 
 through water, the base will be washed out ; and should they 
 be put into the dyeing solution, immediately and directly a great 
 quantity of the coloring matter will be precipitated upon the 
 fibre, not within it, and will thus be left merely adhering to the 
 surface, and, when dry, much of it will of course come off as 
 dust, which is so much loss. Thus, the salts of lead have little 
 or no affinity for the fibre, and if cotton, impregnated with 
 nitrate or acetate of lead, be washed several times, nearly the 
 whole lead is dissolved out. If put through the bichromate of 
 potash solution directly from the lead, a great quantity of 
 chromate of lead will fall to the bottom of the tub, and be lost ; 
 but by passing the goods from the lead solution through a little 
 lime-water, the lime takes away the acid, the lead is fixed with- 
 in the fibre as an oxide, and when put into the chrome solu- 
 tion, combines with the chromic acid, and no chromate of lead 
 is precipitated. Nevertheless, there are colors that require a 
 little of the free mordant to be added to bring out the color. 
 Thus, a piece of cotton passed through red spirits, and then 
 well washed in water, will not lose all the tin. Let the cotton 
 be put into a solution of logwood; this will combine with the 
 base or oxide of tin, and leave the water nearly colorless, giving 
 
MORDANTS. 
 
 217 
 
 a reddish-brown color to the goods, very imperfect, indeed, and 
 not suitable as a dye ; but by adding a small quantity of spirits 
 to this exhausted water, and then immersing the dyed cotton 
 again, instantly the true violet or purple color is brought up. 
 The substances thus added to the colored liquor to change and 
 fix the colors are termed alterants, and the operation, in the 
 language of the dye-house, raising, because it brightens the 
 color. Alterants and mordants are often spoken of as two 
 distinct substances ; but the only distinction is in the mode of 
 applying them. In some instances distinct substances are used. 
 In the process detailed above, a little alum would do as well 
 as the tin : or if a particular bluish shade were wanted, a little 
 pyrolignite of alumina ; but in almost all cases the mordant 
 may also be used as the alterant. This shows that in some in- 
 stances the dye may require some of the acid in the salt, which 
 constituted the mordant, to bring it out ; and must be applied 
 after the color is fixed. If in the above operation the cloth 
 had been passed through the hot logwood solution directly from 
 the spirit tub,, the logwood would have been precipitated ; and, 
 except the decoction had been very strong, the color upon the 
 fibre would have been weak and unequal. Other matters are 
 often added as a sort of alterant in some colors, not to effect 
 the required change of the color, but to take up some sub- 
 stance that may have a tendency to retain the coloring matter, 
 and prevent its uniting with the mordant. Thus it may be 
 necessary with lead mordants, where the acid of the lead is taken 
 away, to add some acid to the chrome solution, to combine with 
 the potash, in order to liberate the chromic acid, and allow it 
 more freely to take the lead. This is particularly the case with 
 Prussian blue. If the goods are washed from the nitrate of 
 iron solution, or passed through an alkali, a little acid must be 
 added to the Prussiate solution, to take the potash and liberate 
 the prussic acid. 
 
 It is with the vegetable coloring matters, however, that the 
 greatest attention must be paid to the many conditions and 
 properties of mordants; some of these may be shortly noticed. 
 
 The mordant, or solvent of the base constituting the mordant, 
 should not be capable of injuring or destroying immediately, 
 or by prolonged action, either the coloring matter or the fabric. 
 Thus acids do not serve as mordants, as they generally either 
 destroy the fabric or the coloring matter; and in cases where 
 destructive acids are used, care has to be taken that they are 
 washed off or neutralized before they have had time to act upon 
 the tissue or upon the color. The principle here stated opens 
 a very wide field of inquiry, embracing the whole range of 
 dyeing operations. The action of bases upon colors, and the 
 
218 
 
 MORDANTS. 
 
 condition of those best adapted to give beauty and permanency, 
 are most important subjects, and deserve that we should here 
 consider them a little in detail. 
 
 1st. The base being insoluble in water, has to be rendered 
 soluble by combining it with an acid, so as to allow the base 
 to combine with the coloring matter. What becomes of that 
 acid which holds the base in solution when the coloring matter 
 combines with the base? Will it act upon the color formed? 
 We have already discussed this point, as regards lead and chrome 
 (page 190) ; we will now take another color, which, although 
 strictly speaking it does not embrace the action of a mordant, 
 will serve very well to illustrate the point of inquiry. Indigo 
 is dissolved in strong sulphuric acid, and is used in this state 
 for dyeing green upon light cotton cloths. The goods are first 
 dyed yellow by bark or fustic, and then dyed blue by means 
 of sulphate of indigo, which gives green. Now, were the yellow 
 dye passed through the sulphate of indigo, the acid would 
 destroy the yellow, and spoil the color ; the acid has, therefore, 
 to be neutralized, and soda or potash is employed for this 
 purpose, according to ordinary practice. We have then the 
 sulphate of the alkali held in solution w r ith the indigo; and, 
 although the acid will not now destroy the yellow, there is 
 another consideration, namely, the effect of this sulphate of the 
 alkali upon the color ; and if there be an effect, it becomes a 
 question how to avoid it. Thus every circumstance produces 
 a new feature, and should be fully studied. 
 
 2d. We must consider the nature and properties of the base 
 constituting the mordant, and its reaction upon the coloring 
 matter, both when combining, and afterwards under exposure. 
 Thus we have stated, when treating of the oxides of iron and 
 tin, that these substances, under various circumstances, are un- 
 stable, the protoxide having a strong attraction for oxygen, 
 and the peroxide, when in contact with organic matters, readily 
 yielding oxygen. 
 
 In one or other of these conditions, these bases combine with 
 the coloring matter. How, then, will the above properties 
 affect the compound ? The action of the peroxide in contact 
 with organic matters, seems to supply an answer to the ques- 
 tion, because in all cases in which peroxides give up their 
 oxygen to the organic coloring matter and become protoxides, 
 the protoxide is the proper condition of applying the mordant. 
 On any other supposition it would be necessary to prove that, 
 when peroxide is applied, the giving up of the oxygen pro- 
 duces a reaction favorable to the resulting color ; but this is 
 seldom if ever the case. The reaction of the peroxide is gene- 
 rally the combination of a part of the oxygen with the hydro- 
 
MORDANTS. 
 
 219 
 
 gen of the coloring matter, which thus becomes partially de- 
 composed. This will be seen by attempting to dye common 
 black with a persalt instead of a protosalt of iron ; or, by 
 adding a persalt of iron to a solution of galls or sumach, and 
 allowing them to stand, the color will be greatly deteriorated. 
 Supposing cloth from sumach put into a solution of persul- 
 phate of iron, there will be a decomposition ; the persulphate 
 being three acid and Voiron, some of the hydrogen of the vege- 
 table color will produce one proportion of free acid by the re- 
 duction of the per to the proto sulphate. When peroxide of 
 iron is fixed upon the cloth free from acid, and put into the 
 colorihg matter, water is formed by the oxygen of the peroxide 
 and the hydrogen of the coloring matter. We then have — 
 
 So that one-third of the coloring matter will be destroyed, and 
 a more imperfect dye will result, as will be more fully illus- 
 trated when we come to describe the composition of the vege- 
 table dyes. 
 
 It is this principle which prevents the use of many oxides 
 of metals that might otherwise be valuable, such as oxide of 
 silver, mercury, &c, which are easily reduced by organic 
 matters. When any of these bases combine with coloring 
 matters as mordants, they are gradually reduced, and pass 
 into the metallic state, the oxygen taking the hydrogen or the 
 carbon of the coloring matter, and thus the color fades away. 
 Still this property of giving up oxygen is often of great value 
 in other operations, as in working with substances that require 
 oxidation to give a color, as in the case of catechu ; salts of 
 silver, mercury, &c, would serve the purposes for which cop- 
 per salts are at present applied to this dye-drug; whereas per- 
 salts of iron cannot be used with this substance for oxygen- 
 izing purposes, as its protosalt blackens the tannin of the 
 catechu, and affects the production of other shades of color ; 
 but where modified tints are required, iron furnishes the 
 means of obtaining them to a great extent. Thus, by a care- 
 ful study of the conditions of the mordants, their relations to 
 the coloring matter, the reactions that will take place under 
 all the varied circumstances of application, and what kind of 
 reaction is required to obtain the results sought, the dyer will 
 find his trade easy, interesting, and pleasant. When the mind 
 
 Peroxide . . . . <{ 0 
 0 
 
 .0 
 
 Hydrogen 
 
220 
 
 MORDANTS. 
 
 guides the hand, labor ceases to be felt either as a curse or 
 degradation. 
 
 In connection with mordants, Dr. Bancroft, in his work on 
 the Philosophy of Permanent Colors, arranges all colors in two 
 classes. He says : — 
 
 "To me, coloring matters seem to fall naturally under two 
 general classes. The first including those matters which, when 
 put into a state of solution, may be fixed with all the perma- 
 nency of which they are susceptible, and made fully to exhibit 
 their colors in or upon the dyed substance, without the inter- 
 position of any earthy or metallic basis. The colors of the 
 first class I shall call substantive, as denoting a thing solid, by 
 or depending only on itself; and colors of the second class I 
 shall call adjective, as implying that their lustre and permanency 
 are acquired by their being adjected upon a suitable basis. 
 
 "Earthy and metallic substances, when thus interposed, 
 serve not only as a bond of union between the coloring mat- 
 ter and the dyed substance, but they also modify as well as 
 fix the color. Some of them, particularly the oxide of tin 
 and the earth of alum, exalting and giving lustre to most of 
 the coloring matters with which they are united ;. whilst 
 others, and especially the oxide of iron, blacken some, and 
 darken almost all such matters, if made to combine with 
 them."* 
 
 This clear definition will remove many erroneous impressions 
 of the meaning of these terms, adjective and substantive. We 
 have often heard an adjective color defined as one that required 
 to be previously mordanted; but this definition is ambiguous, 
 and seems to ground the distinction more upon the mode of 
 dyeing than upon the nature of the color. Thus, by passing a 
 piece of cotton through alum, and then through a solution of 
 logwood, we produce an adjective color, having been previously 
 mordanted ; but if the solutions of the alum and logwood be 
 mixed together, and the piece be passed through this mixture, 
 the same color is produced. Yet, by the above definition, it 
 would be a substantive color, not being previously mordanted, 
 and not because the color produced is neither that of the log- 
 wood nor of the alum, but of the compound formed between 
 them. Again, if we pass a piece of cotton through a solution 
 of copperas, and then through lime-water, there is first produced 
 a light-greenish color, which, by exposure to the air, becomes 
 nankeen or buff; and notwithstanding its thus taking two 
 operations, equivalent to mordanting and dyeing, the color pro- 
 duced is substantive, being the pure peroxide of iron fixed 
 
 * Bancroft on Dyeing, vol. i. page 118. 1813. 
 
MORDANTS. ; v 221 
 
 ■<y. ft •/ 
 
 within the fibre. Another fallacy, we have often heard of 
 identifying substantive and adjective with fast : f^tjitive. 
 The impropriety of this application of the term is show-ii- by 
 simply referring to the two colors, indigo blue and safflower 
 pink ; both are eminently substantive, yet the one is fast and 
 the other fugitive. 
 
 The property which the fibre possesses of fixing portions of 
 the dyestuff within its pores, will have to be often referred to, 
 as ijb bears a very important relation to mordants. Astringent 
 substances, in combining with the fibres of cotton goods, have 
 a strong relation to this action. A piece of cotton, put into a 
 hot solution of sumach, and remaining in it until cool, there is 
 a quantity of the astringent principle fixed upon the fibre, 
 which no washing will remove. We have seen goods thus 
 treated passed afterwards through all the regular operations of 
 bleaching, and still retaining so much of these substances as 
 was sufficient to impart a black tint on passing them through 
 protosulphate of iron. Hence the astringent matters in many 
 vegetable dyes act a very important part in the dyeing opera- 
 tions. Whether such substances as galls and sumach, which 
 are used only for their astringent principle, may be termed 
 mordants, is a question we need not discuss; but they are 
 essentially necessary for fixing within the fibre such quantities 
 of the metallic base or mordant as are required to give depth 
 and permanency to the color ; and as these astringent matters 
 produce tints with the bases, they give us a wider scope for 
 variety of color. Thus, if we pass a piece of cotton through 
 a solution of protochloride of tin, and then wash it in water, 
 we will have a great quantity of oxide of tin fixed within the 
 fibre by the operation of washing (page 177); and by passing 
 this cloth through a decoction of Brazil-wood, and then raising 
 with a little spirits, there is a fine, though not very permanent, 
 rose-red produced. If we pass the cotton through bichloride 
 of tin, and then wash, there is little of oxide of tin fixed ; for 
 the bichloride is not decomposed, as the protochloride is, by 
 water. If, then, it be passed through the Brazil-wood in the 
 same manner as the other, a color of less depth is produced; 
 but if the cloth be previously steeped in sumach, and be then 
 passed through the tin solution, even the bichloride, the astrin- 
 gent principle of the sumach combines with the tin, and forms 
 an insoluble compound ; and there is thus fixed a great quantity 
 of the metallic base, which gives the color with the Brazil-wood, 
 so that when immersed into the wood decoction, there is ob- 
 tained a color of great depth and permanency. But the com- 
 pound of tin and sumach gives a yellow; thus, therefore, 
 peculiar tints of the color are obtained, and instead of having 
 
222 
 
 MORDANTS. 
 
 a rose color, a deep rich red, between rose and scarlet, is pro- 
 duced. Thus sumach, galls, &c, are extensively used in con- 
 nection with metallic bases, to fix, modify, and impart depth 
 to colors for which these bases are applied. The nature of 
 these astringent substances will be given under the distinctive 
 names of the matters which contain them. 
 
 The strong attraction which animal fabrics, as silks and 
 woollens, have for coloring matters is well known, and makes 
 the dyeing of these matters more simple than that of cotton. 
 The mordants used are often of a class that does not act the 
 part of mordants in cotton. From this cause, means were 
 sought to impart to cotton something of the property of animal 
 tissues. Thus, in analyzing a piece of silk, there were found : — 
 
 Composition of Neapolitan silk . . 
 
 Fibres of silk 53.37 
 
 Gelatin 20.66 
 
 Albumen 24.43 
 
 Cerin 1.39 
 
 Fat and resin .10 
 
 Coloring matter .05 
 
 100.00 
 
 It was considered that, in all probability, the substances giving 
 the property to silk to imbibe and fix colors more easily than 
 cotton, were such matters as albumen, &c, which might be 
 imparted artificially. This led to the new process of animal- 
 izing cotton, as it is termed. Upon this subject we extract 
 from the Chemical Gazette, vol. viii. page 384, an excellent 
 article, translated from the Journ. de Chim. et de Pharm., vol. 
 xvii. page 271 : — 
 
 " When an egg is boiled in a color-bath, the color immedi- 
 ately fixes itself to the shell. Egg-shells contain, like bones, 
 an organic tissue and mineral salts. If it is attempted to dye 
 these mineral salts — the phosphate or carbonate of lime — sepa- 
 rately, it fails, and, therefore, neither of these salts can be 
 regarded as the mordant. If, on the contrary, it is attempted 
 to color* the organic tissue of egg-shells or of bones, this im- 
 mediately becomes dyed ; hence it follows that the organic 
 matter of the bones and egg-shells is the mordant. 
 
 "Now, in the same manner as mineral mordants have hither- 
 to been employed to fix coloring matters upon cotton, organic 
 mordants may be used, and Broquette has already employed 
 casein for this purpose. The coating of vegetable fibres with 
 animal substances was first carried out by M. Hausmann, as 
 
MORDANTS. 
 
 223 
 
 observed by M. Barreswil, in this article; but is said never to 
 have attained to any importance. The casein must, of course, 
 be first dissolved, in order that the tissues may be permeated 
 by the solution, but it must then be rendered insoluble in the 
 tissues. Now it has been shown by Braconnot that casein 
 furnishes a soluble compound with ammonia, which is again 
 decomposed by boiling. Broquette, therefore, impregnates the 
 goods with a solution of casein in ammonia, then heats them 
 to expel the ammonia, upon which the casein remains in an 
 insoluble state in the tissues. 
 
 " Cotton goods, after this treatment, are saturated with ani- 
 mal matter, and may now be dyed in the same color-baths as 
 those used for woollen tissues. 
 
 "Frequently the dyes are alkaline; they then dissolve the 
 casein, instead of being fixed by it. But since Bachelier used 
 as a cement a mixture of lime and casein, it is known that 
 this mixture hardens and becomes fixed. Broquette therefore 
 employs the caseine sometimes with lime alone, sometimes 
 with ammonia and lime together, and saturates the goods with 
 this caseate of lime, which soon sets in a warm atmosphere, 
 and then resists the alkalies and rinsing with alkaline liquids. 
 
 "By this treatment the cotton acquires a peculiar stiffness; 
 so that, although its capacity for dyes has become nearly equal 
 to that of wool, it is far behind the latter, owing to want of 
 lustre. But this evil can also be remedied by mixing the 
 mordant with oil. Oil, casein, and lime, form a mordant 
 which fixes the colors with a perfectly remarkable lustre. 
 
 "When the goods to be dyed consist of wool and cotton, a 
 different plan has to be followed; the mordant in this case is 
 not adapted for the two materials; the wool is deprived of its 
 natural lustre, and the cotton tissues are not sufficiently pene- 
 trated. For such goods Broquette employs the mordant be- 
 fore the weaving ; it is applied to the cotton in the spinning, 
 when it can afterwards be woven and bleached like wool, with- 
 out the mordant experiencing any injury. When threads thus 
 prepared are woven, the tissues can be dyed just like woollen 
 stuffs, without further treatment. 
 
 "By means of the solution of caseate of lime, mineral colors 
 which are insoluble in water can be adapted to the dyeing of 
 stuffs; they are mixed in a state of very fine powder with the 
 solution. These liquid colors, which can be prepared, for 
 instance, with ultramarine, ochre, &c, can again be removed 
 with water, "unless they have been dried; but as soon as they 
 coagulate, they adhere firmly to the tissues inclosing the color- 
 ing principle. 
 
 "A farther application of the mordant of casein, oil, and 
 
224 
 
 MORDANTS. 
 
 lime, is in the printing of stuffs: in this case we are not limited 
 merely to mineral colors, which by its aid may be fixed upon 
 the goods, but the numerous vegetable colors may be likewise 
 very well applied, by first converting them into lakes by means 
 of alumina or protoxide of tin, and then using these lakes in 
 the same manner as the powdered mineral colors. After being 
 printed, the goods are wrapped in moist linen, and left for 
 about half an hour in the moist vapor in a warm atmosphere. 
 Daring this time the impressed color does not dry superfi- 
 cially, but is absorbed into the interior of the fibres, and is then 
 completely fixed in the subsequent drying. 
 
 u This new method of mordanting has already had consider- 
 able influence upon several pigments, for instance upon archil, 
 which has only been used for dyeing exceptionally; according 
 to Broquette's process, some very beautiful colors are obtained 
 from it, modifications of the peculiar color of the archil by 
 lime. 
 
 "It will be evident, from what has been above stated, that 
 in this process of dyeing it is requisite to pass the goods 
 through a lime-bath, which will not do for many dyes, as the 
 colors have their tints altered by such treatment. In such 
 cases magnesia is to be substituted for the lime. 
 
 " When goods are printed with the mineral colors or lakes, 
 according to the above process, very full colors are obtained, 
 which, in the case of many patterns, is not desirable. To 
 bring out the shades and half-colors in the full-colored impres- 
 sions, the printed goods are placed with their colored surface 
 upon an absorbing ground, cotton stuff, and the forms pressed 
 on the back. The printed cotton pressed upon the absorbing 
 surface is deprived of some of its color, and numerous patterns 
 can be produced in this manner." 
 
 The preparation of the salts which constitute mordants has 
 been given under the particular element constituting the base 
 of the salt ; but we mentioned that different methods of pre- 
 paring such salts are practised by different dyers, every one 
 preferring his own method, from some real or supposed pecu- 
 liarity or advantage it possesses; although in some cases this 
 difference is difficult to appreciate, both because the acids used 
 are not regularly tested, and also because it is a common cus- 
 tom to take the acids by measure; so that when a dyer says 
 he prefers 4 to 1, he as often means 4 jugs as 4 lbs. Now, 
 nitric acid having a specific gravity much above that of hydro- 
 chloric acid, recipes, in which the proportions are given in 
 volume, will of necessity differ very essentially from those in 
 which they are given in weight. 
 
 Bed Spirits. — These are named from being used in dyeing 
 
MORDANTS. 
 
 225 
 
 red by means of Brazil and other red woods. They are some- 
 times termed nitromuriate of tin, from being prepared by a 
 mixture of these acids. Mix together 
 
 1 lb. Nitric acid, 
 
 3 lbs. Hydrochloric acid. 
 
 Add feathered tin, in small quantities at a time, until the acid 
 ceases to dissolve more ; pour off the clear, and preserve in a 
 dark cool place. This is a spirit for a deep, heavy red. 
 If a red of a bluer or crimson hue be required, then — 
 
 1 lb. Nitric acid, 
 
 5 lbs. Hydrochloric acid, 
 
 dissolving the tin as above, will be a better quality of mor- 
 dant. The proportion of nitric acid gives brown or depth to 
 the red ; but some sorts of woods contain more of the yellow 
 or browning principle than others. Attention ought to be 
 paid to this circumstance, and to prepare the spirits suitably 
 to the character of the wood which is to be used as the dye. 
 This difference of tints is occasionally regulated by the quan- 
 tity of tin dissolved; hence some dyers give a definite quantity 
 of tin, generally from 2 ounces to 2 J ounces to the pound of 
 mixed acids; this is, indeed, not far from what is generally 
 dissolved when tin is added to saturate the acid. Whichever 
 method is adopted, it is necessary that there should always be 
 a knowledge of the quantity of tin which the spirit contains ; 
 and, moreover, as this is commonly prepared in the open air, 
 the quantity of tin dissolved will depend somewhat on the 
 season of the year, on account of the influence which tempera- 
 ture has on the action of the acid. When red spirits are used 
 with logwood, the influence of the proportions of nitric acid is 
 very apparent, causing the purples, or such colors dyed, to dry 
 brownish — a result which the dyer is often called upon to ob- 
 tain or avoid. The spirit-tub in which the yarn is wrought 
 should stand from 2° to 2|° Twaddell. 
 
 Barwood Spirits. — These are named from being used as the 
 mordant for dyeing with that wood. They are prepared with 
 
 1 lb. Nitric acid, 
 
 6 lbs. Hydrochloric acid, 
 
 adding gradually, as dissolved, If ounce of tin to the pound of 
 the mixture; or — 
 
 1 Nitric acid, 
 
 4 Hydrochloric acid, 
 
 2 ozs. of tin per lb. 
 
 This spirit should not be used within at least twelve hours after 
 15 
 
226 
 
 MORDANTS. 
 
 its preparation. There are also other variations in the prepa- 
 ration of this spirit; they vary generally from 4 to 7 hydro- 
 chloric acid. Excess of tin in this mordant is avoided. The 
 same principle regulates the tint more or less. Nitric acid 
 gives the red a brown or crimson hue. The working solution 
 is 2J-° Twaddell; but this dye requires some experience and 
 attention to manage it well. 
 
 Plum Spirits, so called from being used with a decoction of 
 logwood to prepare a dye solution of a deep wine or plum color, 
 sometimes termed a French tub — 
 
 7 lbs. Hydrochloric acid, 
 1 lb. Nitric acid, 
 
 adding by degrees, as dissolved, 1J ounce tin to the pound of 
 mixture; or, 
 
 1 Nitric acid, 
 5 Hydrochloric, 
 
 1J ounce tin to the pound of acid, 
 
 Some prepare it by dissolving the tin in hydrochloric acid alone. 
 In that case, the vessel containing the acid should be placed in 
 a hot situation; it is generally, indeed, placed in another ves- 
 sel containing boiling water. The spirits are also prepared by 
 dissolving some of the salts of tin in hydrochloric acid. For 
 1J to 2 lbs. of logwood used, 1 lb. of the spirits is added. 
 
 Yellow Spirits, as before mentioned (page 183), were pre- 
 pared with sulphuric instead of nitric acid, but they are not 
 now used. 
 
 The above embraces, with very little modification, almost all 
 the qualities of spirits used for cotton. That termed oxymuriate 
 of tin, used often for woollens and silks, is prepared by adding 
 to a solution of the salts of tin in hydrochloric acid, some ni- 
 tric acid, which causes effervescence, and an escape of red fumes 
 of nitrous oxide, in consequence of the peroxidizing of the tin. 
 The same result is often observed in the preparation of the 
 spirits named above, when the tin is added too rapidly, and 
 heat is developed; there is then a rapid solution, and fumes of 
 nitrous oxide are given off, producing what the dyers call firing. 
 Fired spirits, or spirits thus peroxidized, give brownish, dull, 
 and unsatisfactory colors. 
 
 Several qualities of spirits are used forw r oollens and also for 
 silk, by adding sal ammoniac, or common salt, to nitric acid, 
 along with the tin — the former most commonly — by this method 
 a double salt of chloride of tin and ammonia is produced. The 
 proportions of the acid and the sal ammoniac and tin are also 
 varied for different objects ; but spirits prepared in this way 
 are seldom if ever used for cotton. 
 
MORDANTS. 
 
 227 
 
 Nitrate of Iron is prepared by taking a quantity of nitric 
 acid, and adding clean iron (generally old hoops with the rust 
 beaten off) as long as the metal will dissolve. The acid is best 
 to be diluted in the proportion of about one part to six of water; 
 and after it has ceased to act upon the iron, all the metal not 
 dissolved ought to be removed, otherwise the nitrate will con- 
 tinue to dissolve more of it, and precipitate oxide of iron, and 
 thereby produce a thick insoluble mass at the bottom (see page 
 160). Some prefer to add only a small quantity of iron for 
 light shades, but we have never seen any advantage in such a 
 mode of proceeding. The iron and nitric acid ought, however, 
 to be weighed, and have a fixed relation to each other. This 
 solution of iron should be kept in the dark. 
 
 Nitric acid, mixed with much sulphuric or muriatic acid, 
 does not answer well for this solution, as the salts of these acids 
 being crystallizable, require more water than the acids generally 
 have to hold them in solution. Hence the presence of these 
 acids in quantity may cause a confused crystalline mass to be 
 formed at the bottom of the vessel in which the iron is dis- 
 solved. But the small quantities of these acids, often present 
 in commercial nitric acid, are not of material importance. 
 
 Acetate of Iron and Alumina. — This mordant is now sel- 
 dom used; but it is useful for dyeing wine colors, &c, with log- 
 wood. It is prepared by dissolving equal parts of copperas 
 and alum in boiling water, then adding a solution of acetate of 
 lead as long as a precipitate is formed. Allowing this to set- 
 tle, the clear solution is the double acetate. But a better and 
 cheaper mode of preparing is to mix black iron and red liquor 
 together, which form the mordant in question. 
 
 Acetate of Alumina, or Pyrolignite of Alumina (see page 
 144 for an account of its preparation, and the mode of testing 
 it). It is not, however, prepared by the dyer. We may men- 
 tion, as this mordant is often dried upon the cloth in stoves at 
 a high heat, that care should be taken not to allow two pieces 
 of the cloth to hang too closely together, which prevents a free 
 circulation of air; nor ought the stove to be too close, otherwise 
 the warm vapor of the acetic acid will react upon the mordant 
 in the cloth, and give an unequal dye, full of dark parts, thus 
 rendering the color cloudy. 
 
 Black Iron Liquor. — This is pyrolignite of iron prepared 
 by allowing iron to steep in pyroligneous acid. It is not pre- 
 pared by the dyer. We have also given a method of testing 
 it (page 158). 
 
 Iron and Tin for Eoyal Blue. — This is not prepared to 
 stand in reserve, but only when about to be used. The iron 
 used for this color should be well killed, that is, the acid should 
 
228 
 
 MORDANTS. 
 
 be well saturated with iron, and produce a solution of a deep 
 dark red. Some dyers add. a little muriatic acid to the iron 
 when it is to be used along with the tin. The crystals of tin 
 should be added to the iron liquor immediately before entering 
 the goods, and the liquor should be well stirred to prevent in- 
 equality. 
 
 Acetate of Copper. — This is sometimes prepared in the dye- 
 house in the same manner as acetate of alumina, viz., by adding 
 to a hot solution of sulphate of copper (blue-stone) a solution 
 of acetate of lead; the clear liquor is acetate of copper. It is 
 better, however, to purchase it in the crystallized state; this 
 forms a good alterant for logwood blues, but it is not much 
 used in cotton dyeing. 
 
 Bichromate of potash has of late been introduced as a mor- 
 dant for cotton with considerable success, especially in mixed 
 fabrics of cotton and wool. 
 
 There are a variety of other mordants used in woollen and 
 silk dyeing, but. these we do not particularize here, but proceed 
 to enumerate a few theoretical considerations concerning the 
 action of mordants generally, upon silk, cotton, or wool. 
 
 Cream of tartar, or bitartrate of potash, is a very feeble mor- 
 dant alone, still it is universally employed in dyeing woollen 
 fabrics. When used along with alum, sulphate of iron, or 
 chloride of tin, it is a strong mordant, probably owing to de- 
 composition; the sulphuric acid of the alum and iron, and the 
 chlorine with the tin, may take the potash from the tartar, and 
 the alumina, iron, or tin, be converted into a tartrate, and in 
 that state combine more readily with the wool, and be much 
 less destructive of the fabric. Woollen goods seem to require 
 certain thermal and acid conditions of the mordant ; and it is 
 known that a portion of the wool dissolves, and an equivalent 
 of the mordant takes its place ; this has been especially demon- 
 strated of alum mordants. 
 
 For silk, the alum mordant is always used cold, otherwise 
 the lustre of the silk is destroyed; and alum, having the least 
 quantity of acid, is the best and most effective mordant. This 
 explains why the Roman alum is always preferred. It may 
 also be remarked that silk, in relation to alum, comes closest to 
 cotton. 
 
 We copy the following theory of the action of mordants, 
 by M. Dumas, from the Pharmaceutical Times (vol. ii. p. 63): — 
 
 "Cream of tartar, or bitartrate of potash, constitutes by 
 itself a feeble mordant, but which is very often used in dyeing 
 light woollen stuffs, to which we may wish to give a delicate 
 but brilliant shade. It is also employed in the dyeing of ordi- 
 nary woollen goods, but here it is associated with alum, sul- 
 
MORDANTS. 
 
 I 
 
 229 
 
 phate of iron, chloride of tin, &c. Its influence, under these 
 circumstances, consists evidently in determining a double 
 decomposition, from which we have produced a sulphate of 
 potash or chloride of potassium, whilst the tartaric acid com- 
 bines with the alumina, the peroxide of iron, or the oxide of 
 tin. Now it is very probable that the coloring matters remove 
 the alumina, the peroxide of iron, or the oxide of tin, more 
 readily from tartaric than from sulphuric acid. Moreover, 
 the presence of free sulphuric acid would certainly prove 
 injurious, as well to the stuff as to the coloring matter, whilst 
 free tartaric acid can exercise no unfavorable action over them. 
 
 "The operation of subjecting wool to the alum mordant is 
 always effected at the boiling point; the mixture used in this 
 process is a compound of alum and of cream of tartar. One 
 of the objects of this addition is to free the bath of the car- 
 bonate of lime which the water generally retains in solution, 
 and which, acting on the alum, would determine its partial 
 decomposition by producing an insoluble subsulphate of alu- 
 mina and potash, and this accumulating on the stuff, and 
 becoming unequally fixed upon its surface, would lead to 
 stains or blotches on passing the material through the dye- 
 bath. But, independently of the above effect, which might be 
 produced by any acid, cream of tartar appears to be capable 
 of effecting a farther object, by inducing a double decomposi- 
 tion, which transforms the alum into a tartrate of alumina. 
 However this may be, after one or two hours' boiling in the 
 alum-bath, the cloth, which should be constantly agitated so as 
 to cause a more equal application of the mordant, is withdrawn 
 from the copper, and, after thoroughly draining, it should be 
 put aside for two or three days, when we wish to dye it with 
 any full-bodied color. Experience has proved that this repose 
 after the use of the mordant greatly favors the union of the 
 latter with the stuff. In applying the tin mordants, we also 
 make use of cream of tartar. It is, moreover, an indispensable 
 addition where we desire to fix the salts of iron previously to 
 dyeing in black. 
 
 "Woollen cloth, on being dipped into a cold aqueous solu- 
 tion of alum, appropriates to itself a part of this salt, but with- 
 out undergoing any very sensible alteration. MM. Thenard 
 and Board have, indeed, proved that cloth, when thus treated 
 by a cold solution of alum, gives up this salt to boiling water, 
 and that, after a few washings performed at the boiling point, 
 it will have parted with the whole of the alum which it had 
 received in the cold bath. When, however, cloth is boiled in 
 a solution of alum, it yields to this liquid a portion of its organic 
 
230 
 
 MORDANTS. 
 
 matter, which becomes dissolved ; but, at the same time ; It 
 absorbs an equal amount of the alum. 
 
 u We have now merely to show the action which wool under- 
 goes when brought into contact with alum and cream of tartar 
 at one and the same time. It is very possible that there may 
 be in this case a simultaneous fixation of alum, as well as of 
 the double tartrate of alumina and potash, and of tartaric acid. 
 The presence of alum in the cloth when taken from the boiling 
 solution is very evident; that of the tartrate of alumina and 
 potash and of free tartaric acid is only presumable. 
 
 "Silk, in like manner, unites itself with alum when placed 
 in a cold solution of this salt, and afterwards parts with it to 
 boiling water ; it may be reproduced from this liquor by evapo- 
 ration. The action of silk on acetate of alumina is identical 
 with that of wool. It at first absorbs this salt in its pure form ; 
 then by desiccation it loses some acetic acid, and retains a 
 mixture of the acetate together with alumina in its free state ; 
 it gives up a farther portion of this acetate to boiling water. 
 
 "The alum mordant is always used cold with silk; if em- 
 ployed hot, it would destroy its lustre. The bath should not 
 contain cream of tartar when it is intended for this material; 
 on the contrary we here have recourse to a variety of alum of 
 as neutral a character as possible. 
 
 "The theory of the action of mordants is connected in the 
 closest manner with that of dyeing. It may, in fact, be viewed 
 under two very different aspects. Sometimes we admit that 
 there exists a true combination between the stuff and the color- 
 ing matter — a combination which can only be determined by a 
 veritable affinity between these two bodies, and which will 
 present a condition analogous to that which occurs in all chemi- 
 cal combinations ; that is to say, a state of saturation, beyond 
 which the union of these bodies becomes of a very unstable 
 character ; at other times, on the contrary, we regard the dye- 
 ing of stuffs as produced by a nearly mechanical phenomenon, 
 by virtue of which the coloring matters become imprisoned in 
 the meshes of the organic filaments contained in the material 
 to be dyed. This latter opinion is evidently the better founded. 
 It approximates the theory of dyeing to some analogous 
 phenomena which we find manifested by animal charcoal on 
 colored solutions ; for, as the animal charcoal seizes upon the 
 coloring matters contained in an aqueous solution, and renders 
 them insoluble by fixing them in a purely mechanical manner 
 within its own pores ; so may the wool, the silk, and the cotton, 
 appropriate the coloring matters held in solution, and, by fix- 
 ing them in their pores, render them more or less insoluble to 
 water. Experience, however, shows that dyeing thus produced 
 
MORDANTS. 
 
 231 
 
 is wanting both in intensity and in fixity — two qualities which 
 it derives by the previous application of a mordant. Now, we 
 can readily see that the mordants themselves may become fixed 
 in the tissues by similar causes to those which determine the 
 fixation of the coloring matters by animal charcoal. We know, 
 in fact, that this latter body possesses the property of removing 
 from water not only the coloring matters, but also certain salts. 
 There will, therefore, be no difficulty in imagining that silk, 
 wool, and cotton may, in their character of porous bodies, purely 
 and simply seize upon the alum, and that this salt, when once 
 imprisoned in the meshes of the tissue, may, subsequently, 
 react* upon the coloring matter according as this latter, in its 
 turn, penetrates the interior of these materials. 
 
 " We may then refer the phenomena of absorption, which 
 characterize the fixation of the mordants and the penetration 
 of the coloring principles into the tissues, to the same cause 
 as that which determines the action of animal charcoal on 
 certain soluble salts and coloring matters. But, if one of these 
 stuffs be impregnated with alum and then dipped into a bath of 
 soluble coloring matter, it acquires a very deep tint, which 
 appears to be essentially produced by a kind of lac, formed by 
 means of the coloring matter and the base of the mordant. 
 On the other hand, in a great number of cases, the mixture of 
 the above mordant with the dye-bath fails in producing an 
 insoluble precipitate. Thus, when we mix together alum and 
 a decoction of Brazil-wood, no precipitate is formed; and, to 
 obtain a lac from this liquor, we are obliged to add some alkali 
 or alkaline carbonate, such as ammonia; in a word, we must 
 render the alumina free. While admitting, then, in accord- 
 ance with the experiments of MM. Thenard and Board, that 
 the stuffs fix the alum in its natural state, we must acknow- 
 ledge, at the same time, that, by some special action, the 
 tissue subsequently determines the union of the base of the 
 mordant with the coloring matter. This special action is equi- 
 valent to that of the alkali. 
 
 "Now, it is certain that the above-mentioned stuffs possess, 
 in a high degree, the faculty of seizing upon the insoluble 
 coloring matters when these are presented to them in their 
 nascent state. It is thus that cotton becomes dyed of a rose 
 color in a liquor which contains carthamic acid in suspension, 
 arising from the decomposition of carthamate of soda by an 
 acid. In like manner we find wool acquire a black color, 
 when placed in a boiling solution of a salt of iron and tannin, 
 by attracting to itself the black precipitate resulting from their 
 admixture. Consequently, although the dyer generally endea- 
 vors to produce the insoluble compound, on which the color- 
 
 * 
 
232 
 
 MORDANTS. 
 
 ing of the stuff depends, within the very pores of the tissue, 
 still we may affirm that, in many cases, the cloth or other 
 material, when placed in presence of the nascent precipitate, 
 has the property of seizing upon it, and thus acquiring a shade 
 of greater or less intensity. 
 
 "It is to this property (which is due to some hitherto unde- 
 termined cause) that we must undoubtedly refer the reaction 
 which takes place between the alum and the soluble coloring 
 matters, as well as some of those more mysterious phenomena 
 which are manifested in dyeing. How else, indeed, are we to 
 account for the fact that wool so readily takes a scarlet color, 
 while cotton and silk are unable to fix it? How explain the 
 cause of wool so easily appropriating the black precipitate 
 formed by tannin and the salts of iron, while silk, under the 
 same circumstances, acquires a black color only by great 
 trouble and expense ? How, in one word, can we understand 
 why certain colors should fix themselves better on certain 
 materials than on others, unless it be by virtue of some 
 special action, wrongly designated by the name of affinity, but 
 which does not the less constitute a force, or rather a conse- 
 quence of diverse forces of which we must take full account 
 during the operations of dyeing? To confound, in fact, a 
 chemical affinity properly so called, such as is evidenced in 
 ordinary chemical combinations when produced in definite pro- 
 portions, with the phenomena of dyeing, is certainly to mix 
 together two very distinct ideas. The union of silk with 
 Prussian blue, or of wool with indigo, is quite a different thing 
 .to the combination of sulphur with lead. But to consider the 
 tissue as a simple filter, capable of retaining in its pores certain 
 precipitates, and of receiving from them peculiar colors, is to 
 go equally far in an opposite direction ; nor would this sup- 
 position at all explain the mode in which the colored lac is 
 formed in most of the operations of dyeing, operations which 
 are effected by an aluminous salt and a coloring bath, altoge- 
 ther incapable of producing any lac, except by the addition of 
 an alkali for the purpose of setting the alumina at liberty, or 
 of a stuff which has the power of taking up the lac as quickly 
 as it is formed. 
 
 " Among the reasons which induce us to regard the insoluble 
 coloring matters and the stuffs as capable of uniting together 
 by virtue of some special force, we must mention the facts eli- 
 cited by the recent experiments of M. Chevreul, who has found 
 that the stuffs and colors, when once united, form products 
 which are endowed with properties differing, according to the 
 nature of the stuff, in the same given color. The properties 
 
 4 
 
MORDANTS. 
 
 233 
 
 of the dyeing matter are, then, greatly modified by the pecu- 
 liar action of the tissue on the dye. Numerous examples place 
 the truth of this assertion beyond all question. It becomes, 
 therefore, perfectly clear that it is only by an attentive and sys- 
 tematic study of the specific properties of the stuffs, in their 
 relation to the various dyeing matters which we may desire to 
 fix upon them, that we can hope to direct the future progress 
 of the art of dyeing." 
 
234 
 
 VEGETABLE MATTERS 
 
 USED IN DYEING. 
 
 INTRODUCTORY REMARKS. 
 
 In entering upon this division of our subject, we may men- 
 tion that it is not our intention to go through a systematic 
 course of vegetable chemistry, but to confine ourselves to those 
 vegetable substances which are used in dyeing, giving their 
 composition and reactions with bases and other matters used in 
 the dye-house. We may however give, in a few introductory 
 remarks, a general outline of the nature of vegetable bodies. 
 Let us then begin with the consideration of the chemical 
 changes which are supposed to take place in nature, under the 
 influence of light, giving rise to the various colors presented 
 to us in the vegetable kingdom, which will probably aid us in 
 describing the artificial means of imitating nature in these colors, 
 although as yet there is comparatively little known concerning 
 the nature of these changes. For a long time chemists con- 
 sidered iron to be the coloring principle of all animals and vegeta- 
 bles, being almost universally diffused, and capable of assuming 
 a variety of colors either as oxides or solutions; but it was af- 
 terwards demonstrated that the iron present in any vegetable, 
 even in those where it existed most abundantly, was altogether 
 inadequate to produce the splendid colors which vegetables as- 
 sume. Several other hypotheses were proposed to account for 
 the colors of vegetables ; but these hypotheses, not being founded 
 upon inquiry and proof, died at their birth. It is only within 
 these few years that the true method of ascertaining the nature 
 and cause of vegetable colors has been adopted ; that is, by the 
 ultimate analysis of vegetable substances in all their stages of 
 existence; and since then a number of important facts have 
 been made known respecting this interesting subject, and new 
 ones are daily being added ; and we hope that these discoveries 
 will be speedily made available to the practical man. 
 
 The principal elements of vegetable substances are oxygen, 
 hydrogen, carbon, and nitrogen; the last exists in such a mi- 
 nute quantity, that in many cases it is scarcely appreciable ; 
 but, according to the opinion of Liebig, who stands at the head 
 
VEGETABLE SUBSTANCES. 
 
 235 
 
 of this department of chemistry, it is never absent. It is to 
 be remarked, however, that none of the coloring matters of the 
 dye-woods contain nitrogen. There is also a variety of earthy 
 substances in vegetables, such as lime, iron, magnesia, soda, 
 potash, &c. ; but the whole of these never exist in the same 
 vegetable — some of them seem indispensable to the existence 
 of a plant; but they differ according to the nature of the plant, 
 and the soil on which it grows. The three elements, oxygen, 
 hydrogen, and carbon, enter very abundantly into the com- 
 position of vegetables, forming from 95 to 99 per cent. ; but it 
 must not be supposed from this, that all vegetables are alike 
 in their chemical properties ; they may be, and are more varied 
 than the mineral kingdom, considering the few elements which 
 compose them, and are beautifully illustrative of the law of 
 definite compounds (page 35). The following table showing 
 the composition of a few substances which constitute the great 
 mass of all vegetables, will serve to illustrate this point : — 
 
 Carbon. Oxygen. Hydrogen. 
 
 Woody fibre ... 15 10 10 
 
 Gum .... 12 11 11 
 
 Starch .... 12 10 10 
 
 Sugar .... 12 11 11 
 
 It will be observed from the table how little change is 
 necessary to produce an entirely different compound. It will 
 also be observed that gum and sugar are the same in compo- 
 sition, which at first sight appears to contradict the law of 
 definite compounds ; but in analyzing substances such as are 
 named in the table, they are reduced to their elements, and 
 although we obtain the same weight of elements, we have no 
 positive information how these elements may have been united 
 together in the plant. All those bodies which differ in proper- 
 ties, and at the same time give the same number and weight 
 of elements, are termed isomeric, signifying equal parts. The 
 discovery of bodies having the same number of elements, and 
 differing in their chemical properties, excited much interest 
 among chemists, and has led to much careful study and investi- 
 gation; the result has been rather unfavorable to the doctrine 
 of isomerism ; there are substances which our neighbors on the 
 other side of the water would designate the same with a differ- 
 ence — the difference is supposed to be in the numerical arrange- 
 ment of the elements. As, for example, hydrogen and carbon 
 will combine in the proportion of two and two, four and four, 
 and eight and eight, forming three substances, differing con- 
 siderably in chemical properties, although the elements are 
 combined in the same relation ; but, interesting as this subject 
 
236 
 
 VEGETABLE SUBSTANCES. 
 
 is, we cannot in the mean time enter into any lengthened 
 details — it shows us, however, the extensive means employed 
 by nature for giving us a variety of substances. Another point 
 to be observed from the above table is, that the oxygen and 
 hydrogen in each of these compounds are in the same propor- 
 tion, or in that relative proportion in which they unite to form 
 water. Now, it may be stated as a general rule, that when 
 oxygen and hydrogen are united to carbon, in the proportion 
 in which they form water, the resulting compounds are of a 
 saccharine or mucilaginous character; and when vegetable 
 compounds have hydrogen united to carbon without oxygen, 
 or when there is less of that element than would be required 
 to convert the hydrogen present into water, the resulting com- 
 pounds are generally oily, resinous, or alcoholic. A table of 
 the composition of a few of these substances will illustrate 
 this : — 
 
 Oxygen. 
 1 
 
 5 
 5 
 
 2 
 2 
 1 
 
 When the proportion of oxygen united to carbon is in 
 greater quantity than the hydrogen, or when no hydrogen is 
 present, the resulting compounds have generally an acid cha- 
 racter ; green fruits are in this state, which gives them their 
 sour taste, and makes them deleterious to health, either by 
 giving too much acid to the stomach, or the acid being of a 
 directly poisonous nature; but, as the fruit ripens, it takes in 
 or assimilates more hydrogen, and the acid, or at least part of 
 the acid, is converted into a saccharine compound. The follow- 
 ing table will show the composition of a few of the most 
 common acids found in vegetables: — 
 
 Acetic acid (vinegar) 
 Tartaric acid . 
 Citric acid (lemon juice) 
 Gallic acid 
 Tannic acid . 
 
 There are also a number of alkalies, alkaloids or bases, formed 
 in plants, which unite with the acids, constituting a very im- 
 portant feature in the. study of vegetable chemistry, but which 
 
 
 Carbon. 
 
 Hydrogen. 
 
 Oil of turpentine . 
 
 . 10 
 
 8 
 
 Oil of potatoes 
 
 . 5 
 
 6 
 
 Oil of cloves . 
 
 . 23 
 
 14 
 
 Eesin of gamboge . 
 
 . 20 
 
 14 
 
 Caoutchouc . 
 
 . 4 
 
 4 
 
 Beeswax 
 
 . 37 
 
 39 
 
 Pyroxilic spirit 
 
 . 2 
 
 4 
 
 Alcohol . 
 
 . 2 
 
 3 
 
 Carbon. 
 
 Oxygen. 
 
 Hydrogen 
 
 4 
 
 3 
 
 3 
 
 4 
 
 5 
 
 2 
 
 4 
 
 4 
 
 2 
 
 7 
 
 5 
 
 3 
 
 18 
 
 12 
 
 8 
 
VEGETABLE SUBSTANCES. 
 
 237 
 
 we will not in the mean time enter upon farther than to state 
 that they almost all contain nitrogen as an ingredient. 
 
 These being the nature and composition of the principal 
 vegetable compounds, we shall now inquire into the cause of 
 their assuming certain colors, and the effects which acids have 
 upon these colors. 
 
 In our remarks upon light (page 25), we mentioned that 
 colors depend wholly upon the reflection and absorption of 
 light, by the apparently colored substance; but it was also 
 mentioned, that this result depends upon the chemical consti- 
 tution of the particular substance; hence, the inquiry into the 
 cause ^of vegetable colors becomes a chemical one; and, from 
 the chemical laws above described, these colors must have a 
 definite constitution; and when any change of color takes place, 
 there must also be a change of chemical constitution. In 
 prosecuting this inquiry, or rather, in collecting the inquiries 
 of the most eminent chemists upon this subject, we shall begin 
 with the paramount color of the vegetable kingdom, namely, 
 green. 
 
 Green is well known to be a compound color produced by 
 yellow and blue, and is always produced upon cloth by dyeing 
 it, first the one color and then the other. It is not always the 
 yellow that is dyed first, according to the description in chemi- 
 cal books; but sometimes the blue, according to the nature of 
 the dyeing agent, which will be explained in its proper place. 
 Speaking of vegetable green, Berthollet says: "The green of 
 plants is undoubtedly produced by a homogeneous substance, 
 in the same way as the greater number of hues which exist in 
 nature. This color owes, then, its origin sometimes to simple 
 rays and sometimes to a union of different rays ; and some 
 other colors are in the same predicament. Were the green of 
 plants due to two substances, one of which is yellow and the 
 other blue, it would be extraordinary if we could not separate 
 them, or at least change their proportions by some solvent." 
 This idea of Berthollet, that the green of plants is a distinct 
 substance, existing in the plant, has since been verified. It is 
 obtained by bruising green leaves into a pulp with water, press- 
 ing out all the liquid, and boiling the dry pulp in alcohol; 
 when the alcohol is evaporated, there remains a deep-green 
 matter, which, by digesting in water, is dissolved, and freed 
 from a little brown coloring matter with which it was mixed. 
 This substance has been named chlorophyllite. The formation 
 of the chlorophyllite seems to depend entirely upon the action 
 of the solar rays. "It is known that the function of the leaves, 
 and other green parts of plants, is to absorb carbonic acid, 
 and, with the aid of light and moisture, to appropriate its car- 
 
238 
 
 VEGETABLE SUBSTANCES. 
 
 bon. These processes are continually in operation; they com- 
 mence with the formation of the leaves, and do not cease with 
 their perfect development." But when light is absent, or during 
 the night, the decomposition of carbonic acid does not proceed ; 
 it is evident, then, that a plant kept always excluded from the 
 light, must have a difference in its composition. u No one 
 can have failed to observe the difference between vegetables 
 thriving in the full enjoyment of light, and those which grow in 
 obscure situations, or which are entirely deprived of its agency ; 
 the former are of brilliant tints — the latter dingy and white. 
 Numerous familiar instances might be cited, especially among 
 our esculent vegetables; the shoots of a potato produced in a 
 dark cellar are white, straggling, and differently formed from 
 those which the plant exhibits under its usual circumstances 
 of growth. Celery is cultivated for the table by carefully ex- 
 cluding the influence of light upon its stem ; this is effected by 
 heaping the soil upon it, so as entirely to screen it from the 
 solar rays ; but if suffered to grow in the ordinary way, it soon 
 alters its aspect, throws out abundant shoots and leaves, and, 
 instead of remaining white and of little taste, acquires a deep- 
 green-color, and a peculiarly bitter and nauseous flavor. The 
 heart of the common cabbage is another illustration, and the 
 rosy colored aspect of the sides of fruit is referable to the same 
 cause. Changes yet more remarkable have been discovered in 
 plants vegetating entirely without exposure to light. In visit- 
 ing a coal-pit, Professor Robinson found a plant with a large 
 white foliage, the form and appearance of which were quite new 
 to him; it was left at the mouth of the pit, when the subter- 
 ranean leaves died away, and common tansy sprung from the 
 roots."* 
 
 Some very curious and interesting results have been obtained 
 by Mr. Hunt and others, respecting the effects of the different 
 rays of light upon vegetable substances, all going to prove the 
 great influence exerted by that agent over the vegetable king- 
 dom, and that to it we are indebted for the beauty of our fields 
 and gardens. 
 
 From these facts we see that the green color of vegetables is 
 owing to a peculiar approximate element existing in the vege- 
 table, not invariably, nor altogether essential to the plant, but 
 depending upon circumstances; these circumstances being at 
 the same time the best for the health and existence of the plant. 
 This color differs from the other colors of vegetables in the 
 time of its appearing. Flowers of plants do not appear till the 
 plant has reached a certain state of maturity ; but whenever a 
 
 * Braude's Manual of Chemistry. 
 
VEGETABLE SUBSTANCES. 
 
 239 
 
 plant rises above the soil, it immediately begins to assume the 
 green hue, and this hue is continued till the object of the leaves 
 is completed. When a chemical change takes place, the green 
 passes away, and another color, reddish-yellow, takes its place. 
 These changes are effected in different degrees, and in different 
 lengths of time, just according as the leaves have the property 
 of absorbing oxygen gas. Those leaves which continue longest 
 green absorb oxygen slowest. The leaves of the holly will 
 only absorb a small fraction of oxygen, in the same time that 
 the leaves of the poplar and beech will absorb eight or nine 
 times their bulk. These last are remarkable for the rapidity 
 and e&se with which the color of their leaves changes. That 
 leaves do absorb oxygen gas when they change color in autumn, 
 and that it is owing to the absorption of this gas, may be veri- 
 fied by placing some green leaves of the poplar, the beech and 
 the holly under the receiver of an air-pump, drying them 
 thoroughly, and keeping them excluded from light; when taken 
 out, wet them with water, and place them immediately under a 
 glass globe full of oxygen gas, when they will change color; 
 and it will be found that the change of color is just in propor- 
 tion to the quantity of oxygen each absorbs. The consequence 
 of this absorption is the formation of an acid ; in accordance 
 with the law mentioned before. This acid changes the chloro- 
 phyllite, or green principle, from green to yellow, and then to 
 a reddish hue. If we treat green leaves with an acid, the same 
 changes of color take place, and if we macerate a red leaf in 
 potash it becomes green. 
 
 The green of leaves, and the colors of flowers, are common 
 to all vegetables under the influence of light; but there are a 
 number of coloring substances in vegetables which are pecu- 
 liar to certain orders, and which exist as proximate elements 
 sometimes in the leaves, in the woody part, in the juice, in the 
 bark, in the flower, in the seeds, and in the roots. Several of 
 these have been made subservient to our use in the art of dye- 
 ing, and will be noticed separately. 
 
 The various and beautiful colors of flowers are produced by 
 a somewhat different process from that of the green of the 
 leaves, in so far as they do not appear until the plant has at- 
 tained a certain state of maturity. "The leaves of the plant 
 being fully developed, they take in more nourishment from the 
 atmosphere than what is necessary for the existence of the plant. 
 This extra nourishment takes a new direction ; a peculiar trans- 
 formation takes place; new compounds are formed, which fur- 
 nish constituents of the blossoms; fruit, and seed."* 
 
 * Liebig's Agricultural Chemistry. 
 
210 
 
 VEGETABLE SUBSTANCES. 
 
 Many attempts have been made to transfer the coloring 
 matter of flowers to cloth, but without success. In general, 
 they are so fugitive as to change the moment they are brought 
 into contact with the atmosphere, and such of them as can be 
 extracted have no affinity for the cloth. If a third substance 
 be used to give this affinity, it destroys the original color of 
 the vegetable. 
 
 It is very probable that all the colors of flowers depend upon 
 only a few proximate elements formed in the vegetable, in the 
 manner already described, and that their various hues are the 
 consequence of the presence of acids affecting more or less this 
 coloring substance. This is the most probable hypothesis that 
 has been framed, and with which we must rest satisfied till 
 more accurate experiments verify its truth, or give us a better. 
 The following summary of experiments will give some idea of 
 the views held upon this subject: "The expressed juice of 
 most red flowers is blue; hence it is probable that the coloring 
 matter in the flower is reddened by an acid, which makes its 
 escape when the juice is exposed to the air. The violet is well 
 known to be colored by a blue matter, which acids change to 
 red; and alkalies and their carbonates first to green and then 
 to yellow. The coloring matter of the violet exists in the petals 
 of red clover, the red tips of the common daisy of the field, of 
 the blue hyacinth, the hollyhock, lavender, in the inner leaves 
 of the artichoke, and numerous other flowers. The same sub- 
 stance made red by an acid, colors the skin of several plums; 
 probably, also, gives the red color to the petals of the scarlet 
 geranium, and of the pomegranate-tree. The leaves of the red 
 cabbage, and the rind of the long radish, are also colored by 
 this principle. It is remarkable that these, on being merely 
 bruised, become blue, and give a blue infusion with water. It 
 is probable that the reddening acid in these cases is the car- 
 bonic, which, on the rupture of the vessel which incloses it 
 (being a gas), escapes into the atmosphere. If the petals of the 
 red rose be triturated with a little water and chalk, a blue liquid 
 is obtained. Alkalies render this blue liquid green, and acids 
 restore its red color."* 
 
 We need hardly mention that the influence of light in pro- 
 ducing colors, and changing them when produced, is regulated 
 to a great extent by the vitality of the plant ; so that the effects 
 vary in intensity according to the season of the year. When 
 leaves or flowers are taken from a plant, they are both very 
 soon affected by light ; but it has been observed by Sir John 
 Herschel, that flowers plucked at an early period, as when 
 
 * Thomson's Vegetable Chemistry. 
 
GALLS. 
 
 241 
 
 newly formed, are much more sensitive to light than at a later 
 period of flowering, showing that flowers have a period of 
 maturity; and if pulled at maturity, the coloring compound is 
 much more stable, and resists the action of light much more 
 powerfully than when pulled before. This law of development 
 and maturity is universal, and may be the cause of many of the 
 varieties — the superiority or inferiority of many vegetable dyes 
 even of the same kind. 
 
 The vegetable substances used in dyeing may be divided into 
 two classes: first, those which are used not on account of their 
 possessing coloring properties, but because they possess matters 
 that have a strong attraction for the fibre, which they fill, and 
 also form insoluble compounds with the bases, and so enabling 
 them to act the part of mordants to the substances which are 
 afterwards to be applied ; and, second, those substances that 
 are applied or used for the coloring matter they contain. 
 
 The substances comprised in the first class of these are 
 termed astringent, from their producing a roughening or cor- 
 rugating effect upon the mouth, when tasted. All the vege- 
 tables that produce these effects are found to contain certain 
 acids, to which this property of astringency is referable ; and 
 the presence of these acids gives them their value in the dye- 
 house. These acids are gallic acid and tannic acid, or tannin. 
 
 It has been found, from the extensive researches of Dr. Sten- 
 house on the vegetables containing these acids, that the tannin 
 exists in them in a great variety of modified forms, or rather 
 that they give certain modified reactions with chemical agents, 
 the cause of which, analysis has not yet been able to define. 
 For our purpose, we will divide these substances thus acted 
 upon into two: — 
 
 1. Those which give a black precipitate with the salts of iron 
 — for a proper type of which may be cited galls and sumach ; 
 and, 
 
 2. Those which give a dark-olive precipitate with iron — 
 the type of which is catechu. The latter is much more stable 
 in its composition, and less liable to change by standing. 
 
 Galls. 
 
 Upon certain species of oak there grow excrescences which 
 originate in punctures, made by a peculiar insect, for the pur- 
 pose of depositing her eggs. A kind of juice exudes from this 
 puncture, and gradually forms round these ova hard round 
 bodies, varying in size from one-fourth of an inch to an inch 
 in diameter. These substances, from their resemblance to nuts, 
 16 
 
242 
 
 GALLS. 
 
 and from their bitter taste, are called gall-nuts* By the 
 repeated experiments of many excellent chemists upon this 
 substance, it is considered to contain two peculiar principles. 
 One of these, a crystallizable substance, is obtained from a 
 macerated solution of galls, after standing in the air for a long 
 time. This, from its possessing many acid properties, is termed 
 gallic acid. The other is that substance which combines with 
 skins during the process of tanning, changing them into 
 leather, and is termed tannin, or, from its having some acid 
 properties, tannic acid. 
 
 The best galls, according to Sir H. Davy, contain 26 per cent, 
 tannin and 6.2 of gallic acid, but from the circumstance of 
 these two compounds being generally found together in the 
 same vegetable and in variable proportions, it was thought 
 probable that the one produced the other. This supposition 
 was verified to a great extent by M. Pelouze, 
 Fig. 13. particularly as respects the tannin of galls. 
 
 The method for abstracting tannin from galls 
 is as follows: To a vessel, such as that repre- 
 sented in the annexed figure, is fitted by means 
 of a cork, g, a funnel-shaped tube, and the neck c 
 is kept corked, air-tight, during the process. At 
 the bottom of the tube is placed a little clean 
 cotton, as shown at /. Above the cotton is placed 
 a quantity of nut-galls in fine powder, as shown 
 at e. Over this is poured a quantity of common 
 sulphuric ether, sufficient to fill the rest of the 
 tube, as seen at d. A cork is then fitted tightly 
 to the opening at the top of the tube, and the 
 whole set aside. Next day, two layers of liquor 
 are found in the vessel a, one very light and 
 limpid, occupying the upper part, the other 
 having a light amber color, and the consistence 
 of a syrup, occupying the lower part. These liquids are poured 
 into a dropping tube, upon which the finger is kept, and after 
 remaining at rest for a few minutes, they again separate; the 
 heavy liquid is then allowed to fall out into a capsule, and 
 the light liquid retained so that it may be distilled for the sake 
 of recovering the ether. The dense liquid which is in the. 
 capsule is next to be washed two or three times with sulphuric 
 ether, and afterwards dried by a very gentle heat ; the matter 
 left has a spongy appearance, is very brilliant, and generally 
 
 * The excrescences are produced by the cynips (gall-wasp) upon the tender 
 shoots of the quercus infectoria, a species of qak which is common in Asia 
 Minor. When the maggot is hatched, it eats its way out of the nidus. The 
 best galls are those brought from Aleppo and Smyrna. 
 
GALLS. 
 
 243 
 
 of a yellow tint. This is tannin in a state of purity. By this 
 process, from 35 to 40 per cent, can be extracted from nutgalls. 
 
 M. Pelouze found that if a solution of tannin be kept closely 
 corked from the atmosphere, no change takes place; but if left 
 in contact with oxygen, the tannin undergoes a change, and 
 gallic acid is formed. Hence he concludes that gallic acid does 
 not exist except in very minute quantity in vegetables, and 
 that the error of supposing that these two acids existed toge- 
 ther in vegetables, arose from the method adopted to procure 
 gallic acid, which was by allowing the macerated vegetable 
 matter to stand in contact with the air, till the gallic acid crys- 
 tallized from the solution, this being nothing more than a pro- 
 cess for converting tannin into gallic acid by the absorption of 
 oxygen. 
 
 This discovery is of great importance to the dyer, as it 
 points out the evil of allowing liquids, which contain tannin, 
 to stand exposed to the air for any length of time; for although 
 gallic acid and tannin act in a somewhat similar manner with 
 metallic oxides, yet the gallates are much more fugitive than 
 the tannates. For example, if we precipitate tannic acid and 
 gallic acid by a persulphate of iron, they are both dark blue, 
 bordering on black; excepting a slight change of shade, the 
 tannate remains permanent ; but if the gallate be allowed to 
 stand a few hours, it is dissolved in the supernatant liquid, 
 and becomes almost colorless; the sulphuric acid resumes its 
 attraction for the iron, and crystallizes as a protosulphate (cop- 
 peras), and the gallic acid is partly decomposed and partly 
 crystallized. These changes take place in a few minutes, if 
 the liquor containing the precipitate be boiled. Now, if galls, 
 or, what is more commonly used instead, sumach, be allowed 
 to stand until after fermentation takes place, which is very 
 soon, a great portion of the tannin is converted into gallic 
 acid; and, although the cloth dyed in sumach that is thus 
 altered should be, as some dyers affirm, equally dark, it will 
 not be equally fast; but from personal experience, we can say 
 that it is neither equally dark nor equally beautiful. It can- 
 not be so dark, for gallic acid being much more insoluble than 
 tannin, falls to the bottom whenever it is formed, and conse- 
 quently leaves the supernatant liquid much weaker in its dye- 
 ing properties. 
 
 More recent discoveries have shown that tannin is converti- 
 ble into gallic acid by other and much more rapid means than 
 being left to absorb oxygen : these are by the common processes 
 of inducing fermentation. It is well known that fermentation 
 is simply a derangement of the elements of certain complex 
 compounds, and the rearrangement of these elements in differ- 
 
244 
 
 GALLS. 
 
 ent positions and proportions, giving rise to new and altogether 
 different compounds of a more simple nature, that is, having a 
 smaller number of elements. The primary compounds are 
 formed under the unknown influence of the vital principle ; 
 but whenever this is withdrawn, they seem but passively to 
 retain their chemical conditions. The attraction of their ele- 
 ments seems too weak to enable them to resist any marked 
 change of circumstances. Even a slight elevation of tempera- 
 ture is sufficient to overpower their affinities and induce change. 
 As in the case of fermentation, if they are brought into con- 
 tact with a body which is in the act of derangement, that body 
 excites the same derangement in them, and, the equilibrium 
 being disturbed, the elements are left to arrange themselves 
 according to their different attractions. If, for example, we 
 dissolve a little sugar of grapes, which is composed of 12 car- 
 bon, 12 hydrogen, and 12 oxygen, in a little water, and raise 
 the solution to a temperature of about 80° Fah. ; and if to this 
 we add a little yeast, which is a substance whose atoms are in 
 the act of transposition, the yeast does not combine chemically 
 with the sugar, but it communicates to it by contact the action 
 of transposition, and thereby deranges the arrangement which 
 the atoms had assumed to form sugar ; and the atomic elements 
 being thus set at liberty, begin to arrange themselves differ- 
 ently ; every three atoms of the hydrogen combine with two 
 of the carbon and one of the oxygen, forming four atoms of 
 alcohol. The remaining eight atoms of oxygen unite with the 
 remaining four of carbon in the relation of one to two, forming 
 four atoms of carbonic acid gas. Thus the whole sugar is 
 converted into two different substances, of which the yeast 
 forms no part. It only acts the part of a bold revolutionizer, 
 breaking up existing combinations, that new ones may be 
 formed from their elements. Now tannin is found to undergo 
 the same sort of change as the sugar, when brought into con- 
 tact with certain substances; and one of the new compounds 
 formed from this transposition is gallic acid. M. Antoine has 
 indeed directly shown that a very small quantity of nutgalls 
 is capable of converting a large quantity of tannin into gallic 
 acid, and that galls contain a substance capable of producing 
 fermentation amongst the elements of the tannin. The com- 
 position of tannin, as compared with that of gallic acid, is as 
 follows : — 
 
 TANNIN. 
 
 GALLIC ACID. 
 
 7 Carbon. 
 5 Oxygen. 
 3 Hydrogen. 
 
 18 Carbon. 
 12 Oxygen. 
 8 Hydrogen 
 
GALLS. 
 
 245 
 
 The action which is considered to take place during the fer- 
 mentation of tannin by exposure to the air is, that it absorbs 
 or combines with eight proportions of oxygen from the atmos- 
 phere : — 
 
 One proportion of 
 tannin 
 
 Oxygen imbibed 
 
 18 C == equal to j 1 * 
 12 0 = equal to f 1 ® 
 8 H = equal to | ^ 
 8 | 8 
 
 2 proportions 
 gallic acid. 
 
 Water. 
 
 Carbonic 
 acid. 
 
 Now, in proportion as gallic acid is inferior to tannin in its 
 dyeing properties, will be the extent of the evil of allowing 
 liquors which contain tannin, and which depend upon it for 
 their dyeing properties, to stand till fermentation begins. In 
 some liquors this commences in the course of three or four 
 days ; much, however, depends upon the temperature. 
 
 But although galls thus contain within them the property of 
 a ferment, it may justly be asked whether sumach, which has 
 in many operations of the dye-house superseded the use of 
 galls, possesses the same property ? The affirmative — that it 
 does possess the property of exciting fermentation in other sub- 
 stances — has not yet been determined; but from a number of 
 experiments upon the action of various substances on tannin, 
 it would seem either to induce or facilitate fermentation ; and 
 further, we venture to say, that the tannin in sumach is more 
 readily converted into gallic acid than the tannin of gall nuts. 
 If the liquor of galls be allowed to stand exposed to the air, it 
 requires a considerable time before its tannin is converted into 
 gallic acid, but there are a number of substances which, if put 
 into it, cause the formation of gallic acid to proceed much 
 more quickly. Among others, the tartaric and malic acids 
 possess this property in a high degree. Now sumach, accord- 
 ing to some recent analyses, contains a great quantity of malic 
 acid, which, were we allowed to reason from analogy in chemi- 
 cal science, places it under very favorable circumstances for 
 fermentation. Indeed, in certain seasons of the year, we have 
 known it to ferment in forty-eight hours. Whether this fer- 
 mentation was induced first by the tannin or by the coloring 
 matter which it contains — for sumach contains a distinct color- 
 ing matter — we cannot certainly in the meantime determine. 
 But this we well know, that a very short exposure to the air 
 makes it lose its coloring matter. 
 
 It was found by the author quoted above, that a little sul- 
 
246 
 
 GALLS. 
 
 phuric, hydrochloric, or nitric acid, added to a solution of galls, 
 makes it less liable to ferment by exposure. 
 
 The following table, abridged from Brande's Manual of 
 Chemistry, will give some idea of the action of some metallic 
 salts upon a solution of galls or sumach : — 
 
 Names of Salts used. Color of Precipitates. 
 
 Protochloride of manganese . . Dirty yellow. 
 Protosulphate of iron (copperas) . Purple tint. 
 Persulphate of iron .... Black. 
 Chloride of zinc (muriate of zinc) Dirty yellow. 
 Protochloride of tin .... Straw color. 
 
 Perchloride of tin Fawn color. 
 
 Sulphate of copper (blue-stone) . Yellow-brown. 
 
 Nitrate of copper Grass-green. 
 
 Nitrate of lead . . . . . . . Dingy yellow. 
 
 Tartrate of antimony and potash Straw color. 
 
 Tartrate of bismuth and potash . Copious yellow, or orange. 
 
 Sulphate of uranium .... Blue-black. 
 
 Sulphate of nickel Green. 
 
 Protonitrate of mercury . . . Yellow. 
 
 In attempting to draw a practical inference from some of 
 these results, we would, for example, conclude that persulphate 
 of iron is much better adapted for dyeing blacks than protosul- 
 phate, as the former is mentioned as producing a deep black, 
 while the latter gives only a purple tint. It is much to be 
 regretted that in making out these tables, care is not taken to 
 give the results in all their bearings. What is mentioned of 
 these two salts is correct, at the instant the mixtures are made : 
 but in the course of twenty minutes the black from the persul- 
 phate becomes a brownish slate, whereas the purple tint of 
 the protosulphate changes during the same time to a deep 
 black ; and these changes continue till the former has become 
 a light-yellowish slate, and the latter a perfect ink black. 
 
 "W hen trying the difference of effect produced by the per- 
 sulphate and protosulphate of iron upon pure tannin and gallic 
 acid, it may further be observed, that the changes produced 
 with tannin are somewhat similar to those which occur in a 
 solution of galls. With gallic acid the persulphate gives at 
 first a black precipitate, not so dark as the tannate, but in a 
 few minutes it changes to an olive, and continues changing 
 till it becomes almost colorless. With the protosulphate, at 
 first the color is scarcely visible, but after an hour's exposure, 
 it assumes a rich violet. From these facts, it may be concluded 
 that tannin is superior to gallic acid as a dyeing agent for black ; 
 moreover, the compound formed is more insoluble. 
 
GALLS. 
 
 247 
 
 Another circumstance which modifies the results of these 
 experiments in their application to dyeing, is the quality of 
 the water used. If the experiments be performed with dis- 
 tilled water, it will be found on repeating them with common 
 spring water, that one-half of the quantity of stuffs will give 
 the same depth of color ; and that the colors, in this instance, 
 have more of a purple hue, and are much more permanent. 
 This may be illustrated by a very simple experiment. Take 
 two glass jars of equal size, fill them half full with distilled 
 water, and add an equal quantity of a solution of galls, or 
 sumach; put into each an equal number of drops of a solution 
 of protosulphate of iron (copperas) ; the change of color is 
 scarcely perceptible. But fill up one to the brim with spring 
 water, and it almost instantly becomes a dark reddish black. 
 Allow both jars to stand for an hour, the solution with the 
 distilled water will have become a deep violet, while the other, 
 notwithstanding the double quantity of water, is so dark that 
 no light is transmitted ; and it will require one-half more water 
 to reduce it to the same shade as the other, but still retaining 
 more of the reddish hue — which, by the way, makes it superior 
 for black. It will also be found to be much more insoluble, 
 and to require a greater proportion of acid to decompose it. If 
 soft or filtered river water be used instead of distilled water, 
 the distinction is not so great, but still the difference is equal 
 to one-half. The best water which we have used for dye- 
 ing black, and other saddened colors* gave, by analysis, sul- 
 phuric, muriatic, and carbonic acids, lime, a trace of silica, and 
 iron. The whole solid contents did not exceed one grain in a 
 fluidounce, or 160 grains per gallon, which, we may remark, 
 is a large quantity (see page 51). These ingredients probably 
 existed in the water as sulphate, carbonate, and muriate of lime, 
 and carbonate of iron. The iron was in very small proportion ; 
 the carbonic acid and lime greatest. 
 
 Now a dyer, learning his trade in a work-shop where such 
 water was used, could not fail to become a successful dyer of all 
 saddened colors ; but were he taken from this work to another 
 where soft filtered water was used, what would be the result? 
 When he attempted to dye a black with the same quantity of 
 dyestuff he formerly used, he would only produce a dark-slate 
 color; and if he wished to obtain a slate color, he would pro- 
 duce a gray. In this dilemma, the dyer adds stuff till he comes 
 to the desired shade ; but fancy-dyes, bolstered up with stuffs, 
 are not so pretty; besides, the employer, in consequence of 
 
 * A technical name for colors that are darkened by sulphate of iron, which 
 includes drabs, fawns, slates, gray, some kinds of browns, blacks, &c. 
 
248 
 
 GALLS. 
 
 this extra stuff, must either submit to a loss, or discharge the 
 dyer; who, no doubt, considering himself ill-used, talks loudly 
 of his ability in dyeing such colors, and offers to prove that 
 the fault is not in him, but the water. Were this wholly a 
 supposed case, we would pause here, and make an apology to 
 our brethren for these remarks; but not being so, we will 
 rather endeavor to show that the fault is the dyer's. Dyeing 
 being an art wholly dependent upon chemistry for its develop- 
 ment and successful practice, he who practises it, without study- 
 ing chemistry, is like a boy learning to repeat a number of 
 choice sentences from an author, without knowing his letters. 
 Had the dyer alluded to known the principles of chemistry, so 
 far as they are applicable to his trade, he would, on finding 
 that the same quantity of stuffs did not yield the same results, 
 have examined the water to discover where lay the difference, 
 and in this particular case he would find, that instead of add- 
 ing an extra quantity of sumach, copperas, and logwood, to 
 get a good black, a little chalk and hydrous gypsum (sulphate 
 of lime) added to the water, would so qualify it as to render 
 it equally effective with that to which he had been accustomed. 
 
 There are several kinds of galls, but the three following 
 kinds occur in commerce — Aleppo galls, Smyrna galls, and 
 Bast Indian galls. These three kinds consist, according to the 
 ripeness of the apples, of black, green, and white galls. When 
 the galls occur in commerce mixed, they are termed "natural;" 
 and are sorted into the following kinds: picked black, natural 
 black (consisting of black and dark-green galls), dark-green, 
 light-green, natural white (light-green and white galls), and 
 picked white. Aleppo galls are the best; but under this name 
 must be reckoned not only such as come from Aleppo, but 
 also, those derived from Mosul in Natalia, and which are there- 
 fore called in Constantinople and Smyrna lists, not Aleppo, but 
 Mosul galls. This gall recommends itself by its heaviness, and 
 the lighter-colored kinds (white and light-green galls) are fre- 
 quently remarkable from their large size; but the best dis- 
 tinguishing character between the Mosul and Smyrna galls, is 
 the darker kind of the Mosul galls having as it were a bluish 
 bloom, while the Smyrna are of a grayish color. The Mosul 
 gall, moreover, has not so many tubercles as the Smyrna kind. 
 The first is exported from Constantinople and Smyrna, the 
 latter principally from Smyrna. The chief markets are Trieste, 
 Leghorn, Marseilles, and London. The fourth kind of nutgall 
 is the marmorated one, which is brought from Puglia ; the 
 chief staple places are Naples and Trieste. It consists generally 
 of large apples, which have fewer tubercles, and these not 
 acute. They are generally of a whitish-red and greenish color, 
 
SUMACH. 
 
 2-19 
 
 sometimes also darker. Istria produces a very inferior kind of 
 galls ; they are small, commonly of a reddish color, and are 
 much tuberculated. Place of export, Trieste. These are the 
 principal kinds, not to mention others of rare occurrence ; for 
 instance, a kind of gall is brought from Asia Minor and Dal- 
 matia, which is hollow, not heavy, and of a reddish color. 
 Analysis of galls by M. Guibourt: — 
 
 Woody fibre 10.5 ^| The luteo gallic acid 
 
 Water 11.5 ' is applied to the yel- 
 
 Tannin 65.0 j low coloring matter of 
 
 Gallic acid 2.0 J the galls. 
 
 Ellagic acid and luteo gallic 
 
 acid 2.0 Sometimes white 
 
 Extractive matter 2.5 galls are dyed by a 
 
 Gum 2.5 little iron water being 
 
 Starch 2. )- put upon them ; which 
 
 Chlorophylle 0.7 darkens them, and 
 
 Sugar 1.8 makes them appear of 
 
 a better quality. 
 
 100.0 
 
 Sumach. 
 
 Called by botanists rhus coriaria, is a native of Syria. It is 
 diligently cultivated in Spain, Portugal, and in some parts of 
 Italy and Sicily, and known in the market as Sicily, Malaga, 
 Trieste, and Verona; the first is the best quality. A quantity 
 of about 60,000 tons of this dye is used annually in this coun- 
 try. The sumach tree, or rather shrub, grows to a height of 
 about eight or ten feet; the stems are ligneous, and divide at 
 the bottom into many irregular branches ; the bark is hairy 
 and of a brown color. The leaves are winged, have seven or 
 eight pair of jagged lobes, and terminate in an odd one. The 
 leaves are placed alternately upon the branches, which are sur- 
 mounted by flowers of a greenish-white color. The shoots of 
 the shrub are cut down every year close to the roots, and after 
 being dried, are reduced to powder by means of a mill ; the 
 very fine stems are often cut into small pieces, and put amongst 
 the powder. 
 
 We have already referred to the use of sumach in the dye- 
 house ; we speak of it simply as a fit substitute for galls, pos- 
 sessing similar properties, and seemingly passing through simi- 
 lar decompositions by exposure. A little sulphuric acid added 
 to sumach retards fermentation, but it is not a good addition 
 when dark shades are required, and should only be used for 
 
250 
 
 SUMACH. 
 
 sumach which is to stand for some time, or which is to be used 
 for very light drabs. In this case the color obtained is more 
 pleasant — technically more sweet; bat either the addition of 
 acid, or by standing exposed to the air, very soon destroys the 
 coloring matter which sumach contains, and also the depth of 
 shade of dye obtained from it. It is, therefore, always advisa- 
 ble to use the sumach newly boiled. The comparative advan- 
 tages of using it newly boiled and after it has been kept for 
 some time, can easily be ascertained by taking a given quan- 
 tity, boiling it, and allowing it to stand over a few days ; then 
 taking the same quantity, boiling it the same length of time, 
 heating the old solution to the same temperature as the new, 
 and adding to each the same weight of cotton ; the effects pro- 
 duced will be very different, and will, more than any written 
 description, show the importance of attending to this circum- 
 stance. 
 
 Sumach is generally used when the metallic base, or mordant, 
 is iron or tin, and is therefore the bottom? of blacks, reds, &c. 
 Sicilian sumach has a greenish-yellow color. When bright 
 colors of red are to be dyed it is best; also for barwood, an<|| 
 all colors that require clearness. Verona sumach when com- 
 pared with Sicily has a fawn tint ; it is best for deep reds, 
 browns, and blacks. When used for barwood reds the color 
 is heavy, and to use Sicilian sumach for the purposes that Vero- 
 nian is most suitable, would require about one half more in 
 quantity for the same weight of cloth. 
 
 The following process for dyeing black will enable us to 
 illustrate some of the reactions of this substance in connection 
 with the metallic bases : — 
 
 The goods are allowed to steep in a decoction of sumach for 
 twelve hours ; they are then wrought through lime-water, 
 which gives them a beautiful bluish-green color, becoming very 
 dark with a short exposure to the air. If allowed to stand for 
 half an hour, the green color passes off, and the goods assume 
 a greenish-dun shade. When they are at the darkest shade of 
 green, they are put through a solution of copperas ; after 
 working some time in this, and allowing them to stand exposed 
 to the air, they become a black. But if dried from this, it is 
 only a slate or dark gray. They are therefore again put 
 through lime-water, which renders them brown, and then 
 wrought through a decoction of logwood till the color of the 
 wood has nearly disappeared. A little copperas is added, 
 which throws off the reddish hue of the wood, giving them a 
 
 * Bottom is a technical term applied to the preparation of cotton by sumach 
 and the like, for colors. 
 
SUMACH. 
 
 251 
 
 V' < . 
 
 blue shade. This is termed raising the color. The goods are 
 washed from this in cold water, and dried in the shade. When 
 a deep blue-black is wanted, the goods are dyed blue previous 
 to steeping in the sumach. 
 
 The passing of the goods from the sumach through lime, 
 before introducing them into the iron solution, is not essen- 
 tially necessary for producing the color, but is very useful in 
 facilitating the operation, and in giving depth of hue by the 
 iron. This metal is held by the strong affinity of the acid, but 
 the goods, impregnated with lime, being put into the copperas, 
 the lime takes the acid, and the iron, liberated immediately and 
 in greater quantity, takes to the tannin of the sumach. The 
 passing through lime-water from the copperas solution, is for 
 the purpose, also, of neutralizing the acid of the iron upon the 
 goods, which, as a salt, would act upon the logwood, and injure 
 the operation. Washing out of the copperas answers equally 
 well, and for fine goods, where a soft tint of black is necessary, 
 is even preferable. When the goods are passed through the 
 lime, the presence of the alkali is hurtful to the logwood ; there- 
 fore it is best to pass the goods through water before entering 
 tl^m into the logwood. The action of the iron upon this sub- 
 stance is the same as we have described for galls ; a persalt of 
 iron, added or used, gives an immediate black, but not perma- 
 nent; the oxygen seeming to affect the decomposition of the 
 color in some way. When a protosalt of iron, as copperas, is 
 used, the blackening is slower, but more permanent ; showing 
 that it is the most suitable salt to use. It is, however, to be 
 remarked, that the combination of iron and tannin, forming the 
 black color, seems to depend on a state of oxidation of the iron 
 a little higher than the protoxide, and much lower than the 
 peroxide ; that the peroxide, when used, is reduced in oxida- 
 tion, and causes change and loss in reduction, and that the 
 protoxide imbibes oxygen as required* Upon this important 
 inquiry we quote the following from an article by M. Barreswil 
 in the Chemical Gazette, translated from the Comptes Bendus : — 
 
 " When a solution of gallic or of tannic acid, which are 
 colorless, and generally form colorless salts or of the color of 
 the bases, is poured into a solution of the persulphate of iron, 
 an intense blue precipitate is formed, which remains suspended 
 in the liquid. This anomalous fact has frequently excited the 
 attention of chemists; MM. Berzelius and Chevreul have even 
 expressed some doubts respecting the simplicity of the reaction. 
 
 " It has long been known that tannin and gallic acid do not 
 
 *An opinion urged several years ago by the author in the Practical 
 Mechanics' and Engineers' Magazine. 
 
252 
 
 SUMACH. 
 
 precipitate the protosalts of iron when protected from contact 
 with the atmosphere. Berzelius, Chevreul, and Persoz have, 
 moreover, observed that when gallic acid or tannin is conveyed 
 into a salt of the peroxide of iron, it is always reduced to the 
 state of a protosalt. This fact is easily proved by adding to 
 the blue solution produced by the persulphate of iron in a 
 solution of gallic acid, an excess of acetate of lead or of carbo- 
 nate of lime, which precipitates the blue combination, and at 
 the same time the sulphuric acid. A colorless liquid is 
 separated by filtration, in which the presence of iron may be 
 demonstrated in the state of protoxide. 
 
 " These experiments are insufficient to explain this curious 
 reaction. It is not improbable to admit, as MM. Berzelius and 
 Chevreul have done d priori, that the oxygen combining with 
 the gallic acid or the tannin converts them into a new acid of 
 a blue color ; but positive experiments were wanting to decide 
 the point. 
 
 "When a solution of tannin or of gallic acid is poured by 
 drops into a solution of persulphate of iron in excess, no blue 
 coloring is obtained; if there is one produced it is only mo- 
 mentary. Nor is there one formed with the same salt in mifi- 
 mum in presence of chlorine, nor with a protosalt of iron and 
 gallic acid oxidized in various degrees by chlorine, by a salt of 
 silver, or lastly, by the atmosphere in an alkaline solution. 
 
 " When a solution of gallic acid in excess is conveyed into 
 persulphate of iron, and the liquid thrown down by acetate of 
 lead, a blue paste is obtained, which, treated with oxalic acid, 
 forms soluble oxalate of iron ; the blue color disappears en- 
 tirely, and is restored by acetate of soda. The solution of the 
 oxalate, diluted very much with water, treated cautiously with 
 the two prussiates and sulphureted hydrogen, presents all the 
 characters of the salts of iron in the state of peroxide and 
 protoxide. 
 
 " It appears to me that we may conclude from the above 
 facts that, if we start with a protosalt of iron, it is requisite to 
 add oxygen, and, if we set out with a persalt, some oxygen 
 must be removed, in order to produce the blue compound, and 
 that this compound contains the two oxides. In the first case 
 the protoxide of iron combines with the oxygen of the atmos- 
 phere ; in the second, a portion of the oxygen of the peroxide 
 destroys a corresponding portion of the gallic acid or of the 
 tannin, converting it into a brown substance. This substance 
 does not enter into the constitution of the new compound, 
 which must be considered as a salt formed of tannin or gallic 
 acid and of an intermediate oxide of iron, probably of a blue 
 
SUMACH. 
 
 253 
 
 color, the tint of which is slightly altered by this brown sub- 
 stance. 
 
 "To prove in the most evident manner that the blue coloring 
 is not to be ascribed to a blue acid, but to a particular oxide, 
 I endeavored to obtain other blue salts with mineral acids, for 
 instance with sulphuric acid. For this purpose I prepared 
 some mixtures in variable proportions of the protosulphate of 
 iron and of the persulphate, and to avoid an inevitable separa- 
 tion of the two salts from their different degrees of solubility. 
 I removed immediately the water by adding to the solution 
 concentrated sulphuric acid in large excess, taking care to pro- 
 duce &s little heat as possible. In this manner I obtained a 
 thick paste of a deep blue, the tint of which was more or less 
 pure according to the proportions of the two salts of iron ; I 
 likewise produced a blue sulphate, but of very ephemerous 
 existence, by evaporating rapidly a mixture of the two salts of 
 iron; the blue tint appeared at the moment when the mass was 
 nearly dry. On substituting phosphate of soda for the sulphuric 
 acid, I obtained a deep-blue phosphate of iron and some sul- 
 phate of soda, w T hich removed the water immediately. I en- 
 deavored, but without success, to prepare combinations with 
 other salts; the hyposulphite of soda alone afforded an intense 
 blue coloring, but of remarkable instability. This is not sur- 
 prising; there are many instances in chemistry of bases which 
 prefer combining with certain acids and refuse to unite with 
 others; such, for instance, among others, is the protoxide of 
 copper. 
 
 "I made numerous experiments to obtain the blue oxide in 
 a free state ; I succeeded several times, but under circumstances 
 which I was not able to produce at will. It is, however, a well- 
 known fact that, when a protosalt of iron is precipitated with 
 ammonia in contact with the atmosphere, the white precipitate 
 of the protoxide soon becomes green, passing first, however, 
 through blue. 
 
 " The impossibility of obtaining the blue sulphate of iron 
 in a crystalline state, and of isolating the acid of the blue gal- 
 late compound, prevented me from having recourse to analysis 
 in order to arrive at the formula for these intermediate salts; 
 I was forced to proceed by synthesis, which, I confess, is far 
 from being accurate ; and it is with some doubts that I publish 
 the results. 
 
 "Of all the mixtures of protosulphate and persulphate 
 which I experimented on, that which afforded the most pure 
 blue with sulphuric and gallic acids and with the phosphate of 
 soda, contained precisely 3 equivalents of protosalt to 2 of the 
 
254 
 
 CATECHU. 
 
 persalt — proportions which correspond to the cyanide Fe 7 O g , 
 prussian blue. 
 
 " If, as I hope, I have rendered probable the existence of 
 two intermediate oxides of iron, capable of forming salts and 
 of entering into the salts with their peculiar color, I shall have 
 thrown some light on the various tints produced by the differ- 
 ent kinds of astringent substances, morphine, salicylic acid, 
 and some other organic principles ; and likewise on the pro- 
 duction of violet, black, brown, and green tints, with red and 
 yellow-coloring principles, in presence of salts of peroxide of 
 iron. I have convinced myself that all the yellow-coloring 
 substances (for instance curcuma) do not produce green ; that 
 the red-coloring principles (among others aloetic acid) do not 
 give a violet ; and that when there is a production of green (as 
 with the Persian berries and the Quercitron), or of violet (as 
 with madder, logwood, &c), the phenomena are identical with 
 those which occur with tannin and gallic acid. These obser- 
 vations agree, moreover, perfectly with the suppositions of M. 
 Thenard, with the facts published by M. Koechlin-Schouch, and 
 by M. Schlumberger, and which M. Stackler informs me he 
 has found confirmed in his establishment, that the iron mor- 
 dants should be at a fixed degree of oxidation to produce beau- 
 tiful dyes." — Comptes Bendus. 
 
 Catechu. 
 
 This is another substance containing much tannin. We 
 have already noticed some of its peculiarities, but may state 
 further that it is a dry extract prepared from the wood of a 
 species of sensitive plant, named acacia catechu. It was long 
 considered an earthy substance, and termed terra Japonica. 
 The plant is indigenous to Hindostan, and flourishes abundantly 
 in mountainous districts. It grows to about twelve feet in 
 height; the trunk is about a foot in diameter, and covered with 
 a thick dark-brown bark. The extract which is obtained from 
 the tree is made from a decoction of the wood. As soon as 
 the trees are felled, all the exterior white wood is carefully cut 
 away, the interior, or colored wood, is then cut into chips ; 
 narrow-mouthed unglazed pots are nearly filled with these, and 
 water is added to cover them. Heat is applied, and when half 
 the water is evaporated, the decoction, without straining, is 
 poured into a shallow earthen vessel, and farther reduced two- 
 thirds by boiling. It is then set in a cool place for a day, and 
 is afterwards evaporated by the heat of the sun, care being 
 taken to stir it occasionally during that process. When it is 
 
CATECHU. 
 
 255 
 
 reduced to considerable thickness it is spread upon a mat or 
 cloth, which has been previously covered with the ashes of 
 cow-dung, and this mass divided by a string into quadrangular 
 pieces, is completely dried in the sun, and is then fit for sale. 
 
 It is a brittle compact substance, of a dark-brown or choco- 
 late color; has no smell, but a very astringent taste; is soluble 
 in water; contains a great amount of tannin, and a peculiar 
 acid, which has been named catechuic acid. It is the reactions 
 of these ingredients with oxygen and other chemical agents, 
 that constitute its dyeing properties. A solution of catechu 
 in water is a beautiful reddish-brown color, which ought to be 
 kept in miud in perusing the following summary of the re- 
 actions of other substances upon it : — 
 
 Acids brighten the color of the solution ; alkalies darken it, 
 and the shade deepens by standing; protosalts of iron give 
 olive-brown precipitates ; persalts of iron also give olive brown 
 precipitates, but with more green than those of the protosalts ; 
 salts of tin give yellowish-brownish precipitates; nitrate and 
 sulphate of copper, yellowish-brown ; acetate of copper, a 
 brown precipitate; salts of lead, brick-colored precipitates; 
 bichromate of potash, a deep red brown. These reactions alone 
 indicate how very important an agent catechu may be in the 
 hands of the dyer, and how very extensive its applications in 
 the processes of his art. 
 
 There are various qualities of catechu in the market, differ- 
 ing considerably in their value as a dye. The Bombay catechu 
 is met with in square masses, of reddish brown color, and 
 which, when broken, exhibit a uniform texture. Its composi- 
 tion is as follows: — 
 
 " Extractive matter" is a sort of indefinite term, applied to 
 designate a brown matter extracted from vegetables when 
 boiled; its true nature is not known, but the part it may play 
 in the reactions of catechu is probably important, and is at 
 least not to be overlooked. 
 
 Bengal catechu is met with in flattish round lumps, of a 
 light brown color outside, but dark internally. It gives: — 
 
 Tannin .... 
 Gum .... 
 
 Extractive matter 
 Impurities .• . 
 
 52 
 7 
 
 34 
 7 
 
 100 
 
256 
 
 CATECHU. 
 
 Tannin 49.5 
 
 Gum 7.0 
 
 Extractive matter 36.5 
 
 Impurities 7.0 
 
 100.0 
 
 Malabar catechu is imported in large masses, of a light- 
 brown color outside, dark within, and covered with leaves. It 
 
 gives: — 
 
 Tannin 45.8 
 
 Gum 8.0 
 
 Extractive matter 39.9 
 
 Impurities 6.3 
 
 100.0 
 
 There is a sort of catechu brought to this country from 
 India in small cubical masses, about an inch in size. This is 
 a very inferior quality, and, as imported, is easily known from 
 genuine catechu. Sometimes, however, means are resorted to 
 to alter the color of this spurious article, and make it more 
 difficult to be detected. It is often said to contain a great 
 quantity of roasted starch, or British gum, termed dextrine. 
 
 Catechu is often adulterated by other vegetable extracts, 
 and also by sand, clay, and ochre. These last impurities may 
 be readily detected by dissolving a portion of the catechu in 
 water, when any of them contained in it will be precipitated ; 
 or by burning a little of it in a crucible until all organic mat- 
 ter is consumed, when the latter adulterants will remain. We 
 have examined samples of catechu of good color, having 8J 
 per cent, of clay and' sand mixed with them. Good catechu is 
 all soluble in cold water, and gives a clear solution. 
 
 The tannin which is in catechu is not converted into gallic 
 acid by exposure so easily as that in galls; but it is subject to 
 oxidation. When a portion is dissolved in water, the solution 
 has a gummy character, and goods put into it would be affected 
 as by a weak solution of gum ; the threads of yarn, for exam- 
 ple, adhere when dried out of it. The addition of a metallic 
 salt destroys this vicious quality, and those salts answer best, 
 or are most effectual for that purpose, which yield their oxygen 
 most easily. Accordingly the salts of copper are most com- 
 monly used, and they are added to the dissolved catechu before 
 putting in the cotton. The chemical changes which catechu 
 undergoes in the operations of dyeing are not yet well under- 
 stood. The action has been explained in this way : The 
 
CATECHU. 
 
 257 
 
 copper salt oxidizes a portion of the catechu, which, although 
 insoluble in water, is soluble in deoxidized catechu, therefore 
 the whole is held in solution in the bath; the goods become 
 impregnated with this solution, and as the whole of the catechu 
 upon the cloth becomes oxidized, it becomes also dark. This 
 explanation does not account for all the phenomena occurring 
 during the dyeing of browns, &c, with this substance; for if 
 we take two portions of a solution of catechu, and to the one 
 add a salt of copper, to the other a salt of zinc, pass the cloth 
 from these through a solution of lime and expose to the air, 
 the piece treated with the zinc will become dark brown, but 
 not that treated with the copper. The above explanation 
 would lead us to expect the opposite, as copper yields its oxy- 
 gen more easily than zinc. When catechu is oxidized, there 
 is formed an acid nearly of the composition of gallic acid, 
 which has a deep brown color. This is formed when catechu 
 in solution is treated with alkaline matters. The lime, there- 
 fore, in the above experiment may have acted the principal 
 part; but cotton from catechu solution, put through acetate 
 of lead, also gives a deep brown color without alkali. When 
 goods impregnated with catechu are passed through bichro- 
 mate of potash, there is obtained a deep brown ; an oxidation 
 of the catechu takes place at the expense of the chromic acid. 
 Whether the oxide of chromium may act as a base on any 
 part of the dye, we cannot positively affirm; but on burning 
 cotton dyed brown by this means, there is obtained in the ash 
 the oxides both of chrome and of copper; showing that both 
 the copper and chrome used play a part in forming the dye, 
 and that the dye by this method is something more than mere 
 oxidation of the catechu, as in passing the cloth from the 
 catechu through bleaching liquor. 
 
 The reactions of catechu are so varied, that it is now used 
 for almost all compound colors, blacks, browns, greens, drabs, 
 and fawns ; and its permanency renders it of high estimation in 
 'the market. 
 
 The following is the analysis of a sample of catechu by Mr. 
 Cooper, giving a wider range to the matters contained in it, and 
 which will serve to give some better idea of the varieties of this 
 substance; for from its mode of preparation, probably no two 
 samples will give the same proportions: — 
 
 17 
 
258 VEGETABLE SUBSTANCES CONTAINING TANNIN. 
 
 Resinous matter 
 Gummy matter 
 Insoluble matter 
 Water . . . 
 
 Tannin 
 
 Extractive, or coloring matter . 
 
 62.8 
 8.2 
 2.0 
 8.5 
 4.4 
 
 12.3 
 
 98.2 
 
 Valonia Nuts. — These are the cups of the acorn from the 
 valonia oak, which grows in the Dardanelles and the islands of 
 the Archipelago, and throughout all the maritime ports of Asia 
 Minor. They are imported in great quantities from Smyrna 
 and its neighborhood. These contain a great quantity of tannin, 
 and also gallic acid ; 'but they are inferior to sumach or galls for 
 dyeing cotton, and for giving depth of color with the salts of 
 iron. For silk, however, they possess some peculiarities 
 exceedingly valuable for blacks, giving a permanency not ob- 
 tained with the ordinary galls; and, moreover, the production 
 of the proper black with valonia nuts upon silk requires a cer- 
 tain treatment which few dyers have attained, particularly in 
 Scotland. We cannot, for instance, furnish a black upon silk 
 which will withstand unchanged all the operations which a hat 
 undergoes in the process of manufacture — a purpose for which 
 we understand the valonia black is applied. 
 
 Divi Divi, or Libi Davi, is the pod of a leguminous shrub, a 
 native of South America; it has been tried as a dye instead of 
 galls or sumach, but is not much used, now, if at all. 
 
 Myrobalans. — This is the fruit of a tree which grows in 
 India ; it is imported into this country in various forms, has a 
 pale yellow color when new, but becomes darker by age, and 
 then resembles dried plums. It contains tannin, and is some- 
 times used on that account for the operations of dyeing. Its 
 reactions with iron, tin, and alum, are similar to those of sumach, 
 but of less value. 
 
 Oak bark contains a great quantity of tannin, and is used 
 on that account for tanning skins, but it is not much employed 
 in the dye-house, although it may be used for similar purposes 
 as sumach. The bark of the mangrove tree also contains 
 tannin in considerable quantity; there are, indeed, very few 
 vegetables which have not in their composition more or less 
 of tannin, and which may not be used in virtue of this property 
 instead of galls or sumach ; but the quantity in them being 
 much less than in sumach, they are not cultivated for that pur- 
 pose. The bark of the ash, willow, hazel, birch, broom, &c, 
 are often used for dyeing woollens by country people ; and 
 
TESTS FOR TANNIN. 
 
 259 
 
 some of these substances possess peculiar dyeing properties. 
 The husks of several nuts also contain much tannin. The 
 walnut, for instance, has long been used and much esteemed 
 by the French dyers for woollen stuffs ; it gives very fast shades, 
 without previous mordanting, although alum is sometimes used 
 to give variety. The outer peel of this nut is collected for the 
 dyers; they are put into large casks, with water poured over 
 them, and kept for a year or more, as they improve while this 
 process of maceration is prolonged. The roots of the walnut 
 tree are also used for dyeing browns. The husks of the horse- 
 chestnut likewise possess dyeing qualities, and might be ap- 
 plied "advantageously for some purposes. Mahogany sawdust, 
 although not affected much by mordants, possesses dyeing 
 properties of considerable value, yielding with iron a variety 
 of shades of great permanence and beauty. 
 
 Many of the dye-woods which are used for their coloring 
 matter contain tannin, the action of which upon the mordants 
 is often very injurious to the tint. Many varieties of the dif- 
 ferent woods, giving the same color, depend much upon the 
 presence of tannin. The whole woody matter being boiled to 
 extract the coloring matter, the tannin is also dissolved, and it 
 is sure to act upon the mordant in the process of dyeing, pro- 
 ducing an effect very similar to that of adding a little sumach 
 to the coloring matter. In many cases this is done beneficially, 
 but in other cases it would deteriorate the tint required. In 
 such cases the presence of tannin in the coloring matter obtained 
 from the wood does not suit. Mr. Warrington proposed as a 
 practical means of ascertaining the quantity of tannin in any 
 matter, the following test : Premising that a solution of gelatin, 
 isinglass, or glue precipitates tannin ; making a given quantity 
 of this solution by adding drop by drop to a given quantity of 
 the substance to be tested for tannin, also in solution, as long 
 as a precipitate is formed, and marking in the alkalimeter the 
 quantity of gelatin used ; every three grains of pure gelatin is 
 equal to two grains tannin, and accordingly it is easy to arrive 
 at a near approximation of the quality of these dyestuffs. This 
 operation will, no doubt, require a little experience, but it is 
 easily performed, and well deserves attention. 
 
260 
 
 INDIGO. 
 
 In the few introductory remarks we made upon vegetable 
 colors, we mentioned that, besides the green of leaves and the 
 colors of flowers, which we considered common to all vegeta- 
 bles, there were other coloring matters, which existed only in 
 certain kinds of vegetables, and in particular parts of the vege- 
 table. Indigo is one of these ; it belongs to a genus of legu- 
 minous plants found in India, Africa, and America, named 
 indigofera. Botanists have described about sixty species of 
 this genus. These all yield indigo; but the species from which 
 it is usually extracted are the /. anil., the /. argentea, and the 
 /. tinctoria. It is also extracted from a tree very common in 
 Hindostan (the nerium tinctorivm of botanists), and from the 
 woad plant (isatis tinctoria), which is a native of Great Britain, 
 and of other parts of Europe. The coloring matter of these 
 plants is wholly in the cellular tissue of the leaves, as a secre- 
 tion, or juice, not, however, in the blue state in which we are 
 accustomed to see indigo, but as a white substance, which, as 
 we shall presently see, remains white, so long as the tissue of 
 the leaf remains perfect. When this tissue is by any means 
 destroyed, the indigo absorbs oxygen from the atmosphere and 
 becomes blue. 
 
 Of the early history of indigo little is known ; neither is it 
 known when it was first used as a dyestuff. The Greeks and 
 Eomans used it as a paint under the name of indicum. Its 
 value as a dyestuff' was not known in Europe till nearly the 
 close of the sixteenth century, when it was imported from India 
 by the Dutch; but our legislators, for a long time, prohibited 
 its use in England under severe penalties. These prohibitions 
 continued in force till the reign of Charles II., and the reason 
 assigned was that it is a corrosive substance, destructive of the 
 fibres of the cloth, and therefore calculated to injure the cha- 
 racter of the dyers of this country. This opinion, no doubt, 
 sprung from the strong and interested opposition to its use by 
 the cultivators of the woad, which was then regarded as an 
 important branch of national industry. 
 
 "When indigo was first introduced, only a small quantity 
 was added to the woad, by which the latter was much im- 
 proved; more was afterwards gradually used, and, at last, the 
 quantity became so large, that the small admixture of woad 
 served only to revive the fermentation of the indigo. Ger- 
 
MANUFACTURE OF INDIGO. 
 
 261 
 
 many thus lost a production by which farmers, merchants, 
 carriers, and others, acquired great riches. In consequence of 
 the sales of woad being so much injured, a prohibition was 
 issued against the use of indigo in Saxony, in the year 1650; 
 and in the year 1652, Duke Ernest the Pious caused a proposal 
 to be made to the diet by his envoy, that indigo should be 
 entirely banished from the empire, and that an exclusive privi- 
 lege should be granted to those who dyed with woad. This 
 was followed by an imperial prohibition of indigo on the 21st 
 of April, 1654, which was enforced with the greatest severity 
 in his dominions. The same was done in France; but in the 
 well-known edict of 1669, in which Colbert separated the fine 
 from the common dyers, it was stated, that indigo should be 
 used without woad, and in 1737, dyers were left at liberty to 
 use indigo alone, or to employ a mixture of indigo and woad." 
 — Barloitfs Manufactures and Machinery of Great Britain. 
 
 The plant which yields the indigo in Bengal is a small 
 straight plant furnished with thin branches, which spread out 
 and form a sort of tuft; the average height is four feet, but on 
 good ground it sometimes attains a height of even seven feet. 
 The leaves are soft, and somewhat like those of the common 
 clover, and the blossoms are of a light-reddish color. The plant 
 is at its greatest perfection, and yields the greatest quantity of 
 indigo, when in full blossom. 
 
 There are two methods of extracting the coloring matter 
 from the leaves : the first is by fermentation and beating. This 
 process is conducted in two large brick cisterns or vats, built 
 in relation to one another, like two steps of a stair. The upper 
 one is termed the steeper, because in it the fermentation is 
 conducted. At the bottom of this cistern there is a plug-hole 
 through which, when the process of fermentation is finished, 
 the fluid is run off into the lower cistern, denominated the 
 beater, because in it the process of beating the fluid by paddles, 
 to separate the fecula from the water, is performed. The plant, 
 when cut, is tied up in bundles about five feet in circumference, 
 and conveyed as quickly as possible to the vat; for, were it 
 kept but a short time in heaps, the indigo in the plant would 
 be destroyed. The upper vat is filled to about five or six inches 
 from the top with these bundles laid in regular tiers. To pre- 
 vent the throwing up of the herb by the swelling and agitation 
 caused by the fermentation, there are irons built in the two side 
 walls, opposite to one another, to which are fastened beams of 
 wood, which traverse the whole length and breadth of the vats. 
 When the vat is sufficiently filled with the vegetable, a strong 
 grating of bamboo, large enough to cover the whole surface, is 
 laid over the plant, and fastened down by the cross-beams. 
 
262 
 
 INDIGO. 
 
 These precautions being completed, cold water is poured as 
 quickly as possible into the vat, till the surface rises within 
 three or four inches of the upper edges. In a short time fer- 
 mentation commences, and is completed in from nine to twelve 
 hours. Towards the end, the action is very brisk, swelling and 
 throwing up frothy bubbles, which sometimes rise like pyra- 
 mids. These bubbles are white at first, but after a little expo- 
 sure to the air, they become blue, and then purple. This part 
 of the operation requires great skill. If the fermentation be too 
 long, the indigo will be much damaged ; and, if too short, the 
 quantity is much diminished. When the liquor ceases to swell \ 
 it is let out into the second or beating vat, and is then of a 
 light-green color. 
 
 The liquor being now in the lower or beating vat, a number 
 of men enter it,. furnished with oar-shaped paddles, about four 
 feet in length ; they continue to walk backwards and forwards, 
 agitating or beating the liquor with these paddles. At the com- 
 mencement of this agitation, the liquor begins to froth; but 
 this is prevented, provided the fermentation has not gone on 
 too long, by a few drops of oil. In the course of an hour and 
 a half, the liquor begins to granulate, and assume the appear- 
 ance of agitated water, full of wood grounds or sawdust This 
 part of the process also requires considerable care and manage- 
 ment; for, if the beating be stopped too soon, the indigo will 
 not be all separated from the liquor, occasioning a proportionate 
 loss ; if continued too long, the granulated particles are broken, 
 and dispersed through the liquor, and do not readily fall to the 
 bottom. When the beating is completed, the vat is allowed to 
 settle ; the grains which constitute the indigo fall to the bottom, 
 and the supernatant liquor is let off* by plug-holes in the side 
 of the vat. The precipitate is then removed to a copper boiler, 
 to which there is a fire kept till the liquor becomes as thick as 
 oil. Some manufacturers bring it to this state by causing the 
 liquor to boil; others by keeping it at a moderate temperature. 
 The former process produces lighter indigo than the latter. In 
 this state it is put into a large flat vessel, furnished at the one 
 end with a cloth filter. After most of the liquor has filtered 
 through, the indigo remains in the vessel about the consistence 
 of butter. It is then put on proper frames, and subjected to 
 considerable pressure by a sort of screw-press ; and is now ready 
 to be cut into small cakes, which are placed upon boards in a 
 drying stove; when dry, these cakes are packed up, and in 
 this state form the indigo of commerce. 
 
 The other method of extracting the indigo from the plant 
 differs from that described, only in the first operations. In- 
 stead of putting the plant into the vat when newly cut, it is 
 
MANUFACTURE OF INDIGO. 
 
 2H3 
 
 spread out, to dry in the sun for two days, and then thrashed 
 to separate the leaves from the stems. The leaves are then 
 kept until they have changed from a green to a bluish gray, 
 or lavender color; they are then put into the first vat with 
 warm water, and kept stirring till the leaves are so completely 
 wetted as to sink. The liquor is then instantly let off into the 
 beating vat, where it is treated as already described. 
 
 The chemical changes which take place during these opera- 
 tions are not well understood, and the various opinions ex- 
 pressed by chemists concerning them are not very easily recon- 
 ciled. Berthollet, in his Elements of Dyeing, while describing 
 the process of the first or fermenting vat, says: u In the first a 
 fermentation is excited, in which the action of the atmospheric 
 air does not intervene, since an inflammable gas is evolved. 
 There probably results from it some change in the composition 
 of the coloring particles themselves, but especially the separa- 
 tion or destruction of a yellowish substance, which gave to the 
 indigo a greenish tint, and rendered it susceptible of suffering 
 the chemical action of other substances. This species of fer- 
 mentation passes into a destructive putrefaction, because the 
 indigo, as we shall see, has a composition analogous to that of 
 animal substances." 
 
 Dr. Ure, in his Dictionary of the Arts and Manufactures, says, 
 that from some experiments made upon the gases given off 
 during fermentation, they were found to be composed, when 
 taken about the middle of the operation, of 27.5 of carbonic 
 acid gas, 5 8 of oxygen, and 66.7 of nitrogen, in the 100 parts ; 
 and towards the end of the operation, they consisted of 40.5 of 
 carbonic acid gas, 4.5 of oxygen, and 55 of nitrogen. No car- 
 bureted hydrogen is disengaged. " The fermenting leaves," 
 using the Doctor's words, " apparently convert the oxygen of 
 the air into carbonic acid, and leave its nitrogen free. They 
 also evolve a quantity of carbonic acid spontaneously. It will 
 be observed that these two opinions are decidedly contradictory ; 
 the one says that the action of the atmosphere does not inter- 
 vene, and that an inflammable gas is evolved ; the other, that 
 there is no inflammable gas evolved, and that the air is appa- 
 rently the principal agent in effecting the various changes. 
 But when we recollect that the leaves are all under the liquor, 
 and kept so by the fixed position of the beams, there can be 
 little contact between the fermenting leaves and the air, except 
 that held by the water, and among the leaves, and of the plants 
 themselves ; hence the conversion of its oxygen into carbonic 
 acid gas must be very limited." 
 
 Sir Eobert Kane says of this process : " After some time, a 
 kind of mucous fermentation sets in; carbonic acid, ammonia 
 
INDIGO. 
 
 and hydrogen gases are evolved, and a yellow liquor is ob- 
 tained, which holds the indigo dissolved. The theory of this 
 action is, that by the putrefaction of the vegeto-animal matter 
 of the leaves, the indigo is kept in the same white soluble con- 
 dition in which it exists in the plant." 
 
 Dr. Thomson, in his Vegetable Chemistry, supposes that the 
 indigo exists in the plant in union with another substance, and 
 during fermentation that substance is decomposed, and carbonic 
 acid gas consequently evolved. But we will give his. own 
 words : " The leaves of the indigofera yield a green infusion to 
 hot water, and a green powder may be precipitated from it; 
 but unless a fermentation has taken place, neither the color 
 nor the properties have any resemblance to those of indigo. 
 There is little doubt that in the leaves it exists in the state of 
 white or deoxygenated indigo, and that during the fermentation, 
 it combines with the requisite quantity of oxygen to convert it 
 into blue indigo. The evolution of carbonic acid gas renders it 
 not unlikely that the white indigo was in combination with 
 some principle (probably of an alkaline nature) which was de- 
 composed during the fermentation." 
 
 These discrepancies of opinion relative to the nature of the 
 changes which take place during fermentation, show that pro- 
 per investigations have not yet been made into this part of the 
 process; and it is obvious that until this be done, any hypo- 
 thesis founded upon statements concerning the* gases evolved, 
 must be unsatisfactory. The supposition hazarded by Dr. 
 Thomson certainly appears to us the most consistent; for as 
 deoxidized indigo combines readily with alkaline substances, 
 and as the vegetable alkalies almost always contain nitrogen, 
 we can easily conceive of that gas being evolved either free or 
 in combination with hydrogen, forming ammonia. It may yet 
 be found that indigo, like gallic acid, does not exist in the liv- 
 ing vegetable, but is the result of a decomposition of some 
 more complicated compound. 
 
 The chemical action w T hich takes place in the second vat in 
 which the beating process is conducted, is apparently much 
 more easily explained, and therefore the discrepancies among 
 writers on the subject are not so great. We shall give only- 
 two quotations. Berthollet says : " Hitherto, the coloring par- 
 ticles have preserved their liquidity. In the second operation 
 the action of the air is brought into play, which, by combining 
 with the coloring particles, deprives them of their solubility, 
 and gives them the blue color. The beating serves at the same 
 time to dissipate the carboni^ acid formed in the first operation, 
 which action is an obstacle to the combination of the oxygen." 
 Dr. Ure's opinion is thus expressed: "The object of the 
 
MANUFACTURE OF INDIGO. 
 
 265 
 
 beating is threefold ; first, it tends to disengage a great quantity 
 of carbonic acid present in the fermented liquor; secondly, to 
 give the newly-developed indigo its requisite dose of oxygen 
 by the most extensive exposure of its particles to the atmos- 
 phere ; and thirdly, to agglomerate the indigo in distinct flocks 
 or granulations. In order to hasten the precipitation, lime- 
 water is occasionally added to the fermented liquor in the 
 progress of beating; but it is not indispensable, and has been 
 supposed to be capable of deteriorating the indigo." 
 
 That the liquor in the beating vat absorbs oxygen from the 
 air, as the indigo separates from it, has, we believe, been 
 ascertained by direct experiment; and it is also known to 
 manufacturers, that the sunshine assists in the separation of the 
 indigo from the liquor. But, though these facts may have 
 been ascertained, it does not give us any positive information 
 respecting the nature of the change which takes place in the 
 vat ; neither can we expect such information till it be ascer- 
 tained what keeps the indigo in solution previous to the opera- 
 tion of beating. Both oxygenized and deoxygenized indigo 
 are insoluble in water ; there must therefore be some substance 
 in the liquor capable of holding the indigo in solution previous 
 to being beaten. According to our present knowledge of the 
 nature of white or deoxidized indigo, there is no other substance 
 which can hold it in solution except the alkalies and alkaline 
 earths. But during such a generation and emission of carbonic 
 acid gas, the existence of any known alkali capable of holding 
 the indigo in solution in those vats is next to impossible, and 
 the results prove the contrary ; for while the acid is liberated, 
 the indigo becomes more insoluble — a result which is just the 
 opposite of what we conceive would take place were an alkali 
 present — except we suppose that the carbonic acid is the result 
 of the decomposition of the alkali, or alkaloid, or is evolved 
 as already hinted, from the decomposition of a substance which 
 is resolving itself into indigo. 
 
 Having given the opinions of several chemists upon the 
 chemical nature of the manufacture of indigo, and hinted at 
 the difficulties which some of these theories involve, we shall 
 now consider the nature of indigo ; and, whatever be the 
 chemical changes which take place in the beating operation, we 
 are certain that the indigo is precipitated in union with vari- 
 ous other substances, rendering it very impure. The best indigo 
 of commerce, according to several analyses, contains only 75 
 per cent, of pure indigo, while some of the inferior kinds do 
 not contain above 29 or 30 per cent. Part of these impurities 
 may be dissolved in water, by alcohol, by dilute acids, and by 
 alkaline lyes. Berzelius found those impurities to consist, 
 
266 
 
 INDIGO. 
 
 besides a little iron, of clay, lime, magnesia, and silica, of a 
 substance resembling vegetable gluten,* which may be obtained 
 by digesting indigo in dilute sulphuric acid (vitriol); also a 
 brown matter, which he terms indigo brown, and which he ob- 
 tained by digesting the indigo in strong potash lye after the 
 gluten had been extracted. He found likewise a red resinous 
 substance, which he termed indigo red; it was obtained by 
 boiling the indigo in alcohol, after digestion in the acid and 
 alkali. Several experiments have been made upon the color- 
 ing properties of these substances, but the results have shown 
 that they are incapable of being used as a dye. On the con- 
 trary, as we shall afterwards have occasion to remark, some of 
 them being more soluble than the pure indigo, and much more 
 easily decomposed, their presence is very hurtful, especially 
 when the indigo is to be used as sulphate of indigo. 
 
 From the great differences in the quality of the indigo, it 
 would be of the utmost importance to the dyer to have an easy 
 method of ascertaining its true value. This, so far as we are 
 aware, has not yet been obtained; the various methods pro- 
 posed generally imply formal analyses, which, however im- 
 portant they may be to the dyer, are too delicate and tedious 
 to be generally adopted. The method universally practised in 
 the dye-house is that of comparison— putting several samples 
 together, and breaking and comparing their clean surfaces. 
 The best indigo generally is of the deepest violet blue, and the 
 finest grain, and if scratched by the nail, it presents a copper 
 hue; but, notwithstanding great care and long practice in 
 judging of the value of indigo in this way, it often happens 
 that the lot -chosen turns out to be of inferior quality — a fact 
 which is not discovered until it is in the vats. 
 
 The process of Berzelius, just alluded to, is to take a weighed 
 quantity of the indigo of commerce in very fine powder, and 
 after digesting it in dilute sulphuric acid, to filter and wash it ; 
 then digest what remains on the filter in strong potash or am- 
 monia ; filter and wash again ; then boil the remainder in strong 
 alcohol ; what remains is pure indigo, and, by weighing it, we 
 find the percentage of real indigo in the sample. 
 
 Another process, somewhat similar, was recommended by 
 Chevreul. He treated the powdered indigo first with water, 
 then with alcohol, and afterwards with muriatic acid. The 
 following is the result of his experiment, taking a hundred 
 parts : — 
 
 * Gluten is the substance which gives wheat, flour, starch, &c. the pro- 
 perty of paste. It is a distinct vegetable substance, composed of oxygen, 
 hydrogen, nitrogen, and carbon, and it is the most nutritive of all vegetable 
 compounds. 
 
TESTING INDIGO. 
 
 267 
 
 Treated with 
 water. 
 
 Treated with 
 alcohol. 
 
 Treated with 
 muriatic acid. 
 
 There* 
 remained, 
 
 f Green matter united to ammonia "] 
 ' A little deoxidized indigo 
 
 Extractive matter .... 
 
 Gum J 
 
 Green matter ) 
 
 Eed resin I 30 
 
 A little indigo ) 
 
 Eed resin 6 
 
 Carbonate of lime ..... 2 
 
 Eed oxide of iron 2 
 
 Alumina 3 
 
 Silica 3 
 
 Pure indigo 45 
 
 12 parts. 
 
 103 — 
 
 Although these processes give a much nearer and more 
 certain approximation to the true value of indigo than the 
 mere comparison of samples by the eye, still they are not 
 direct enough, and require too much nice management to be 
 resorted to generally in the dye-house. Those, indeed, who 
 are most affected by a bad bargain, and ought to be most in- 
 terested in any process that would enable them to avoid loss, 
 and who have the requisite time and means to try such experi- 
 ments, do not seem impressed with the importance of such 
 inquiries. 
 
 Another method has been proposed by Dr. Dana, of Lowell, 
 United States, for ascertaining the real value of commercial 
 indigo. He directs that ten grains of indigo reduced to a very 
 fine powder, be put into a small glass flask, with two and a 
 half ounces, by measure, of a solution of carbonate of soda, of 
 from 30° to 35° of strength by Twaddell's hydrometer ; after 
 boiling for a few minutes, 8 grains of crystals of chloride of tin 
 are to be added, and the whole boiled for half an hour. By 
 this means the indigo is dissolved, and the liquor appears of a 
 yellow color. Six grains of bichromate of potash (red chrome) 
 are dissolved in six ounces of water ; and when the flask is with- 
 drawn from the lamp, this solution of chrome is added, which 
 precipitates the indigo blue, along with a trace of the indigo 
 red, leaving the other ingredients in solution. The whole is 
 next to be poured upon a double (weighed) filter, and the pre- 
 cipitate washed with 1 ounce of muriatic acid diluted with 3 
 ounces of boiling water, and afterwards with hot water, till 
 nothing but water returns. Then separate, dry, and weigh the 
 filters, and make a note of the weight of the precipitate ; burn 
 one filter paper against the other, and their difference in weight 
 is the quantity of silica contained in the indigo. This deducted 
 
268 
 
 INDIGO. 
 
 from the weight of the precipitate, gives the quantity of pure 
 indigo. Mr. Walter Crum, who communicated the above to 
 the British Association, in 1841, added that carbonate of soda 
 with protoxide of tin, dissolves indigo, and forms a yellow 
 solution, but so slowly, that he doubts if all the 10 grains are 
 acted upon. He thinks Dr. Dana must mean soda-ash, which 
 contains a notable quantity of caustic soda, but a much weaker 
 solution of caustic soda would answer the purpose. 
 
 Pure indigo, besides its great importance as a dye-drug, 
 possesses some most important and interesting chemical pro- 
 perties, but which are as yet not very well understood. Some 
 of these we shall notice before entering upon its practical 
 value. If pure indigo be heated to about 550° Fah., it sub- 
 limes, producing a beautiful transparent vapor of a reddish- 
 violet color, which adheres to the sides of the vessel in which 
 it is sublimed, or on the top of the cinder left, in long needle- 
 shaped crystals. Mr. Crum whose investigations have thrown 
 great light upon the chemical nature and properties of indigo, 
 employed for its sublimation the covers of two platinum cruci- 
 bles, about three inches diameter, and of such a form that, 
 when placed with their concave sides inwards, they were about 
 three-eighths of an inch distant in the middle. About the 
 centre of the lower lid were placed thinly about ten grains of 
 indigo, precipitated from the dyer's vat, in small lumps about 
 a grain each; then, having put on the cover, the flame of a 
 spirit lamp was applied beneath the cover containing the indigo. 
 The indigo immediately began to melt with a hissing noise, 
 which, when it had nearly ceased, the lamp was withdrawn, 
 and the whole allowed to cool. On removing the cover, the 
 sublimed indigo was found planted on its inner surface and a 
 little remained upon the charred matter, and was easily re- 
 moved. In this way he obtained from 18 to 20 per cent, of 
 the indigo employed.* 
 
 As few workingmen have access to platinum crucible covers 
 to repeat this experiment, we may state, that it may be suc- 
 cessfully repeated by taking a thin porcelain plate, or a sheet 
 of iron or copper, with the indigo placed upon it, and covering 
 it with a pretty large watch-glass ; when the plate under the 
 indigo is heated by a lamp, the vapors very soon make their 
 appearance; and, towards the close, the glass appears black, 
 owing to the coating of indigo which adheres to its inner 
 surface. To obtain pure indigo for this experiment, the easiest 
 method is to take a little of the yellow solution of the indigo 
 vat. On adding to this a few drops of muriatic acid, to dis- 
 
 * Annals of Philosophy for January, 1823. 
 
TESTING INDIGO. 
 
 269 
 
 solve the salts of lime, the blue indigo falls to the bottom, 
 and may readily be collected upon a filter, then washed and 
 dried. 
 
 Another method has been described by T. Taylor, Esq., 
 which is as follows: "Any quantity of indigo is to be reduced 
 to powder, and mixed with about half its weight of plaster of 
 Paris. To these materials, so much water is to be added as 
 will bring the whole to a thin paste. This is to be spread 
 evenly upon an iron plate to the depth of the eighth of an 
 inch, and allowed to remain exposed to the air, or to a gentle 
 heat, until it is tolerably dry. If the heat of a large spirit- 
 lamp 'be now applied to the under surface of the plate, the 
 indigo begins to smoke, emits a disgusting odor, and in a few 
 minutes is covered over with a dense purple-red vapor, which 
 condenses into brilliant flattened prisms, or plates of an intense 
 copper color, forming a thick velvety coating over the surface- 
 immediately exposed to heat. When this ceases to appear, the 
 heat is of course to be withdrawn ;■ and when cold the sub- 
 limed crystals may be readily lifted or swept off, without in 
 the slightest disturbing the subjacent mass. The operation is 
 exceedingly beautiful to look at, is effected in a few minutes, 
 and any quantity of materials might be acted upon. For 
 ultimate analysis, the sublimed indigo must be previously 
 washed with alcohol or ether. The object of the plaster is to 
 prevent the indigo from cracking during drying.* 
 
 We have tried this experiment repeatedly, but the results 
 did not promise favorably for the process being of practical 
 value in the dye-house. 
 
 Another method, and of much easier practice in the dye- 
 house than any of those given, is by Henry Schlumberger :— 
 
 " This test consists in dissolving the indigo in fuming sul- 
 phuric acid, and decolorizing the solution, which has been 
 diluted with much water, by means of chloride of lime. As 
 this acts only on the blue coloring substance, and not at the 
 same time on the various other bodies which indigo contains, 
 the quantity of chloride of lime requisite to produce decoloriza- 
 tion agrees, as will be subsequently seen, accurately with the 
 amount of coloring matter. 
 
 " The operations in this experiment are as follows: I pre- 
 pare, in the first place, a portion of pure indigo or indigo blue 
 by removing the scum which is continually formed on the blue 
 vat, treating it with an excess of dilute hydrochloric acid, 
 washing the deposit until all soluble parts have been removed, 
 then drying it and preserving the indigo in well-closed bottles, 
 
 * Chemical Gazette, vol. i. page 115. 
 
270 
 
 INDIGO. 
 
 in order to protect it from all changes in the moist state: In 
 all my experiments this pure indigo serves as a standard, and 
 for comparison with the results which the various kinds of in- 
 digo submitted to the test afford. Suppose the quantity of 
 coloring matter in the purfe indigo to be 100°, I express the 
 value of the tested indigo by numbers which indicate the per- 
 centage of pure coloring matter. In each experiment I employ 
 the standard indigo for comparison with that of commerce, as 
 it is then not requisite to determine previously the amount of 
 chloride of lime in solution ; besides which, the experiment is 
 more accurate. In this case the causes of the differences in the 
 results depend on circumstances, which always remain the same 
 whether the standard indigo is employed, or the indigo the 
 degree of purity of which is to be ascertained. Twenty grains 
 of each kind of indigo are weighed off, which must be pulver- 
 ized and finely ground ; half an ounce of fuming sulphuric acid 
 is added, and the mixture is now rubbed together, the dish 
 containing it being placed for four hours at a temperature of 
 from 122° to 140°. 
 
 " Meantime as many glasses, containing about a quart, are 
 filled with distilled water as there are sulphate solutions, and 
 to each solution of indigo is added its equal volume of water 
 from the glass. The liquid becomes warm, upon which they 
 are rubbed again ; water is then gradually added until the dish 
 is full, when the whole is poured into the glass, and the dish 
 washed with a portion of the water. Hereupon a solution of 
 chloride of lime is prepared of 2° Twad. in strength, and a given 
 quantity taken, say 10 graduations of an alkalimeter. 
 
 u The well-stirred blue solution of the sulphate of indigo is 
 now measured in an alkalimeter, a tube divided into 100°, and 
 a portion poured into a dish, well stirred, and the entire quan- 
 tity of the chloride of lime contained - in the measure added at 
 once. If the liquid immediately assumes a yellow color, it is 
 a sign of an excess of chloride of lime, and now sulphate of 
 indigo is added by degrees until a faint olive-green coloring 
 has been obtained. The experiment is now repeated, and the 
 quantity of chloride of lime which had been found necessary 
 in the first case added to the quantity of sulphate of indigo; so 
 that with one single mixing, there being neither an excess of 
 chloride of lime nor of sulphate of indigo, the liquid acquires 
 that tint at once. But when, after the first mixture, the liquid 
 has retained a blue color, which is a sign of an excess of the 
 sulphate of indigo, fewer degrees of it are taken until the requi- 
 site tint has likewise been attained with a single mixing. 
 
 " When the several indigoes have been treated in this man- 
 ner, the following calculation is made to obtain the true value 
 
TESTING INDIGO. 
 
 271 
 
 of the indigo which has been examined ; the goodness of the 
 indigo is in inverse ratio to the quantity of sulphate of indigo 
 employed in decolorizing. 
 
 " Suppose, for instance, it were found that pure indigo re- 
 quired 54 parts of its sulphate solution to be decolorized by 
 the fixed quantity of chloride of lime, and that, on the other 
 hand, the indigo under examination required 64 parts of its 
 sulphate solution, then according to the proportion — 
 
 100x54 
 
 64 : 54=100 : cc, =cc, or equal to 84.5, which 
 
 64 
 
 indicates the quantity of indigo blue contained in 100 parts of 
 the ftidigo examined. 
 
 " It is important for the accuracy of the experiment that the 
 pure indigo, and the kinds of indigo submitted to the test, 
 should be equally moist, and it is therefore requisite to inclose 
 all the samples as soon as they are taken out of the chests in 
 glass phials, to prevent any attraction of moisture or desiccation 
 previous to weighing. When a chest contains several kinds 
 of indigo which exhibit slight differences in their tints, some 
 pieces are selected which are separated into several lots ; these 
 are then powdered together, and the mean result taken as the 
 correct one. But when, as often happens, a chest contains 
 pieces of indigo of entirely different tints, it is best to examine 
 the mixed sorts separately. 
 
 "I also dilute the solution both of the sulphate of indigo 
 and of that of the chloride of lime, since the experiment in this 
 manner is less exposed to error than with concentrated solutions. 
 Besides, it is easier when the liquid is only faint blue to distin- 
 guish the degree of decolorization, when it must be discontinued. 
 
 " Impure water, or such as contains salts of lime, produces 
 a more or less considerable precipitate of the blue-coloring sub- 
 stance mixed with sulphate of indigo ; it is therefore necessary 
 to employ rain or distilled water. 
 
 u The last stage of decolorization, or the point at which it is 
 best to discontinue it, is the more easily ascertained, the purer 
 the indigo, and the more complete its solution ; and in this 
 case it is evident how sensitive the reaction of the chloride of 
 lime is on the indigo; for a yellow solution of indigo, to which 
 chloride of lime has been added, in which, therefore, there is 
 an excess of chloride of lime, is rendered blue by a single 
 degree of the indigo solution, a proof that this method will 
 indicate a half per cent. In the commercial kinds of indigo it 
 is less easy to fix the point at which decolorization must be 
 discontinued, for in this case the decolorized liquid assumes an 
 
272 
 
 INDIGO. 
 
 olive color, and from 2° to 3° of the indigo solution must be 
 added to change the yellow color into the blue. 
 
 "I have preferred the method of taking a fixed quantity of 
 the chloride of lime and varying that of the sulphate of indigo, 
 to that of making the sulphate of indigo a fixed quantity, and 
 allowing the decolorizing agent to be diminished or increased, 
 from its being possible to dilute the indigo solution with much 
 water, which has the advantage of rendering the degrees 
 greater." 
 
 Another method, and of much easier practice in the dye- 
 house, is thus given by M. Reinsh : — 
 
 Reinsh tried various modes of determining the goodness of 
 indigo — such as the external appearance ; the intensity of 
 color imparted to yarn by the cold vat; the quantity of ifdigo 
 blue obtained by sublimation; the quantity of indigo blue 
 deposited from the cold vat ; and the specific weight. Not one 
 of these methods, however, gave results to be relied on. 
 
 "At last," he says, "I resorted to fuming sulphuric acid, 
 and obtained the most satisfactory results. It is necessary, 
 however, that the indigo should be pounded very fine, and the 
 acid should be as concentrated as possible. I must also 
 observe, that the solution of the Java indigo, and of that indigo 
 which I prepared in a chemical way, by treating it with acid, 
 caustic potash, spirit of wine and water, did not possess the 
 pure blue color like that of the Bengal sort, although I repeated 
 the experiments several times, and could not, therefore, deter- 
 mine anything with regard to the purified indigo. A dyer of 
 great experience informed me, that for solution in sulphuric 
 acid he prefers Bengal to the Java sort, as the latter is burnt 
 by the acid, which is always the case when the indigo does not 
 dissolve with a pure blue color, but assumes a crimson hue on 
 the sulphuric solution being poured in water. 
 
 " The mode in which I proceed is as follows : 2 grains of each 
 sample of indigo are well pounded, mixed with four or five 
 drops of fuming sulphuric acid, and rubbed with it until the 
 whole forms a brown uniform mass. To this, 15 grains of 
 sulphuric acid are added, and triturated till it produces a clear 
 green solution, whereupon other 15 grains of fuming sulphuric 
 acid are added; lastly, this solution is gradually mixed with 
 150 grains of water. Two glass cylinders of equal length and 
 width are now divided each into twenty equal parts, and 15 
 grains of the sulphuric solution (which is best measured by a 
 glass tube closed at one end) poured into one and mixed with 
 water, till the solution is of a light-blue color and transparent ; 
 if 15 grains of the solution do not produce sufficient coloriza- 
 tion, a small quantity more of it is added, till the cylinder is 
 
TESTING INDIGO. 273 
 
 filled with the light-blue solution. I generally commence with 
 the apparently best indigo. After this, the second cylinder is 
 filled in the same way with an equal quantity of sulphuric 
 solution of the same indigo sample and water, in order to see 
 whether the two solutions are equal in color. If this be the 
 case, one of the cylinders is emptied, and an equal quantity of 
 sulphuric solution of an inferior sample poured into it and 
 gradually diluted with water, till the solutions in both cylinders 
 are perfectly alike in color. Care is to be taken that the 
 coloration be not too intense nor too light, it being in either 
 case difficult to obtain both solutions of the same hue. For 
 discovering this equality the eye will also be much assisted if 
 the relative position of the cylinders is changed from the right 
 to the left, or by placing them alternately before or behind one 
 another. As soon as the color of both is thus found to be 
 equal, the quantity of water is examined which has been poured 
 into the second cylinder. Supposing now that 15 grains of 
 sulphuric solution have been employed in either of the cylinders, 
 but the quantity of water which produced the equal color was 
 in the first or standard cylinder 20 parts, and in the second 
 only 15 parts, then the sample of which the latter solution was 
 made will contain 2 5 o^ ns ? or one quarter less of coloring matter. 
 
 "This method is so easy and convenient that everybody can 
 avail himself of it. All that is required is to keep ready 
 a certain quantity of indigo solution of a known quality as 
 standard solution, and then to prepare a sulphuric solution of 
 the indigo to be tested. 
 
 u The above-described method may even be made more 
 accurate, if longer glass cylinders are used, so that the per- 
 centage quantities may be indicated. The glasses must then 
 be divided in 100 parts. The larger the degrees are, the more 
 accurate will the results be. 
 
 "I have yet to add some observations with regard to an 
 adulteration practised on the indigo, and which is of import- 
 ance to the druggist. Each large indigo-chest contains a 
 quantity of dust, which is said to amount sometimes to eight 
 or ten pounds. This dust is an artificial product, composed of 
 starch or white lead and powdered indigo, and is put in the 
 chest in order to increase its weight." 
 
 Another process of testing the value of indigo has been re- 
 commended by Dr. Bolley, depending also upon the decoloriz- 
 ing by chlorine, by a method which insures the constancy of the 
 chlorine; this is done by using hydrochloric acid and chlorate 
 of potash. A given quantity of indigo, say 100 grains, is 
 ground into powder, and converted into sulphate of indigo by 
 adding to the 100 grains about 2J ounces of the strongest sul- 
 18 
 
274 
 
 INDIGO. 
 
 phuric acid, and allowing it to stand for six or eight hours. 
 The whole is now put into an evaporating basin or flask, with 
 about one pint of water, and one quarter of an ounce, by mea- 
 sure, of hydrochloric acid, and brought to boil. A solution of 
 chlorate of potash is now made in 100 measures of water by 
 alkalimeter (which is added to the indigo solution), the blue 
 liquor passes into green, brownish-green, and lastly into red, 
 when the operation is finished. A little experience will show 
 the exact time to stop. The amount of chlorate solution taken 
 to effect this is noted, and a standard solution being made, the 
 relative value of indigo will be easily ascertained. 
 
 Another method of testing the value of indigo has been re- 
 cently recommended by Dr. Penney, of the Andersonian Univer- 
 sity, Glasgow, based upon the circumstance that indigo blue, 
 in presence of hydrochloric acid, is decolorized by bichromate 
 of potash. Ten grains of the sample, in very fine powder, are 
 dissolved in 2 drachms, by measure, of fuming sulphuric acid, 
 forming sulphate of indigo. After standing several hours, to 
 insure complete solution, it is diluted with a pint of water, and 
 the whole well stirred, after which there is added f of a volume 
 ounce of hydrochloric acid. Seven and a half grains of dry 
 and pure bichromate of potash are now dissolved in water — 
 the whole solution to be equal to 100 measures of an alkalime- 
 ter; this is added drop by drop to the sulphate of indigo, until 
 the blue color disappears, and the color of a drop of the solu- 
 tion put on a white plate or paper be orange-brown, having no 
 green or blue tint. The number of graduations required to 
 effect this is noted. Dr. Penney found that 7| grains bichro- 
 mate of potash were equal to 10 grains pure indigo, so that 
 every ten graduations of the solution taken to decolor the sul- 
 phate, are equal to one grain of pure indigo, or one graduation 
 to a per cent, of indigo. 
 
 Commercial Indigoes. — The following description of com- 
 mercial indigoes is taken from Dumas' Lectures upon Agricul- 
 culture : — 
 
 " Indigoes of Commerce. — The indigoes of commerce have 
 been described in a very able manner by M. Chevreul. The 
 following details are extracted from his work: They are some- 
 times in small, light pieces, of a violet-brown color, and some- 
 times in cubical loaves. These loaves may be considered good, 
 when they assume a copper-colored aspect on friction with any 
 hard and smooth body — when there are no cavities found in 
 their interior, presenting a series of brown or whitish-colored 
 streaks — and, lastly, when they are free from fissures externally. 
 If they are of a blue instead of a violet color, it is a proof 
 that they contain more or less of the yellow matter. The 
 
COMMERCIAL INDIGOES. 
 
 275 
 
 presence of this matter in large proportions, tends by its ad- 
 mixture to convert the blue into a green, and also neutralizes 
 the color of the red matter of indigo. An obscure dark-brown 
 or dirty-green color indicates, in general, that the indigoes have 
 undergone some deterioration in their preparation or during 
 their transport. Indigo is destitute of odor, provided it has 
 undergone no alteration by heat and moisture. Indigoes are 
 classified into different kinds, according to the country in which 
 they are prepared, or according to their color. 
 
 " First, Indigoes prepared in Asia — they are from Bengal, 
 Coromandel, Madras, Manilla, and Java: — 
 
 " Bengal Indigoes. — The trade in this indigo is chiefly carried 
 on in Calcutta, and through the medium of the East India 
 Company; its varieties are very .-numerous. The principal, 
 commencing with those of the best quality, are: 1° The super- 
 fine or light blue. This is im a cubical form, light and friable, 
 soft to the touch, of a clean fracture, and giving a beautiful 
 copper color on being rubbed with the nail. 2° Superfine 
 violet. 3° Superfine purple. 4° Fine violet, in color a little 
 less brilliant than the superfine, and rather heavier. 5° Fine 
 purple violet. 6° Good violet, somewhat heavier than the fine 
 violet. 7° Violet red. 8° Common violet. 9° Fine and good 
 red, heavier than the preceding, color bordering decidedly on 
 red. 10° Good red, of a firmer and more compact structure. 
 11° Fine copper-colored, redder and more compact still. 12° 
 Middling copper-colored. 13° Ordinary and low copper- 
 colored ; this is of a copper-colored blue or red, somewhat diffi- 
 cult to break. 
 
 " Coromandel. — Those of the best quality correspond to the 
 middling Bengal indigoes, and are met with in square masses, 
 having an even fracture, but are more difficult to break. The 
 inferior indigoes are heavy, of a sandy feel, having a blue color 
 bordering on green or gray, or even black ; often in very large 
 squares, and covered with a slight crust or rind of a greenish- 
 gray color. These are the most difficult to break of all the 
 indigoes of commerce. 
 
 "Madras. — They have a grained rough fracture, and are of a 
 cubical figure. The superior qualities have no rind ; in figure 
 they somewhat resemble a hat, and are more light and friable 
 than those of Coromandel. These indigoes, when of the best 
 quality, have great lightness, but are not equal to the superfine 
 blue of Bengal. The middling qualities have a very slight 
 copper-color. The color of the inferior qualities is a dark or 
 muddy blue, black, or even gray, and greenish. 
 
 64 Manilla. — These present the mark of the rushes upon which 
 they have been dried. They are of a finer consistence and 
 
276 
 
 INDIGO. 
 
 lighter color than are the indigoes of Madras, but not so fine 
 as the indigoes of Bengal. The better qualities are often in flat 
 and elongated masses, somewhat porous, and consequently light. 
 The middling qualities are of a violet color, but they are infe- 
 rior to the violet of Bengal. 
 
 " Java. — In flat, square masses, sometimes of a lozenge shape. 
 The superior qualities appear to the sight as fine as the blue, 
 violet, or red indigoes of Bengal ; but they are not so in 
 reality. 
 
 " Second, Indigoes prepared in Africa. They are from 
 Egypt and Senegal : — ■ 
 
 " Egypt. — The superior qualities of Egyptian indigo are su- 
 perfine and fine violet blues. They are light, but their struc- 
 ture is not very fine, and they often contain sand. The squares 
 are rather flatter than those of Bengal. 
 
 " Senegal. — They are of good quality, but they contain more 
 earthy matter than any other indigoes in the trade. 
 
 " Third, Indigoes from America ; those of Guatimala, Carac- 
 cas, Mexico, Brazil, Carolina, and the Antilles: — 
 
 " The indigoes of Guatimala, of the Garaccas, and of Mexico, 
 are of various kinds. The best are of a bright blue color, 
 remarkably light and fine. These indigoes are esteemed equal 
 to the best Bengal. The inferior qualities are of a violet color, 
 but, in general, are more mixed than the Bengal kinds. 
 
 " Brazil. — These indigoes are in small rectangular parallel- 
 opiped masses, or in irregular lumps, of a greenish-gray color 
 externally, and having a smooth fracture, a firm consistence, 
 and a copper-colored tint of greater or less brilliancy. 
 
 " Carolina. — In small square masses, having a gray exterior. 
 The best qualities have a dull copper color, bordering on violet 
 or blue. The common qualities are almost always of a green- 
 ish-blue ; they are rarely found of a copper color. 
 
 "The principal varieties of indigo in commerce are the 
 Bengal, the Caraccas, the Guatimala, the Madras, and the 
 Manilla. 
 
 "Besides the numerous shades already described, we should 
 also be on our guard against certain defects of greater or less 
 consequence, and which depend on causes acting either on the 
 indigo when already prepared, or else occurring during its 
 preparation. The following are some of the characters to be 
 borne in mind : The large or small fracture ; squares of indigo 
 reduced, by accident, into lumps of variable size. Fragments: 
 squares reduced into irregular pieces, and fine enough to be 
 passed through a sieve. Sometimes, also, we meet with squares 
 which are readily broken, and which present a whitish kind of 
 mouldiness in their interior. Gritty lumps, throughout which 
 
CHARACTERISTICS OF INDIGO. 
 
 277 
 
 are points presenting the appearance of granite. Streaky 
 masses, in which are layers of various shades of blue, placed 
 one above the other, in the same square. Pieces of a scorched 
 appearance, which, on being sharply rubbed between the 
 hands, are ground into small fragments, nearly black in color. 
 Sandy lumps, in the interior of which the eye can detect 
 shining specks, which are nothing more than sand." 
 
 Pure indigo, whether obtained by sublimation or other 
 chemical means, is of a deep blue approaching to violet. If 
 scratched or rubbed, it has a strong copper hue, and a metallic 
 lustre. It has neither taste nor smell, and is remarkable for 
 its neutral properties. It is insoluble in water, alcohol, ether, 
 alkalies, and dilute acids. Strong sulphuric acid dissolves 
 indigo readily, and forms with it a purple-blue solution. Its 
 chemical composition is, according to Mr. Crum and M. 
 Da mas : — 
 
 16 Carbon. 
 5 Hydrogen. 
 2 Oxygen. 
 1 Nitrogen. 
 
 or double, 
 
 r 
 
 32 Carbon. 
 10 Hydrogen. 
 
 4 Oxygen. 
 
 2 Nitrogen. 
 
 The double proportion is preferred, as it agrees better with 
 some of the reactions to be hereafter explained. 
 
 The chemical qualities, and some of its reactions have been 
 extensively studied. If blue indigo be brought into contact 
 with substances having a strong attraction for oxygen in the 
 presence of an alkali, the indigo is reduced to the white state, 
 and becomes soluble in the alkali ; this, as is well known, is 
 the principle of the blue vat. The following matters all reduce 
 blue indigo to whiter- 
 
 Protoxide of tin, 
 Protoxide of iron, 
 Sulphuret of arsenic, 
 Phosphorus, 
 The phosphites, 
 Sulphites, 
 
 The sulphurets of potassium, 
 
 Sodium, 
 
 Calcium, 
 
 Sugar, 
 
 Starch, 
 
 Tannin. 
 
 Salts which yield oxygen, as those of copper, turn white 
 indigo to blue, and the copper is reduced to the suboxide. 
 Water having carbonic acid, also oxidizes white indigo. In- 
 digo white is a crystalline solid, having a fibrous silky lustre, 
 tasteless, without smell, and heavier than water; it is insoluble 
 in water, but soluble in alcohol and ether. 
 
 White indigo, well dried, may be kept in the air for several 
 days without change, but if moist it soon becomes blue ; when 
 heated it becomes purplish-blue. The composition of white 
 
278 
 
 INDIGO. 
 
 indigo is still, to some extent, an unsettled question. According 
 to the most generally received opinion, white indigo is blue 
 indigo with less oxygen, sometimes called deoxidized indigo, 
 but Dumas considers it as blue indigo, with an equivalent more 
 of hydrogen ; thus we have 
 
 By the Common Theory. By Dumas 's Theory. 
 
 Carbon 16 Carbon 16 
 
 Nitrogen 1 Nitrogen 1 
 
 Hydrogen 5 Hydrogen 6 
 
 Oxygen 2 Oxygen 2 
 
 Dumas supports his view of the matter by reference to 
 many vegetable organic substances which he thinks comport 
 themselves in a similar manner, and gives a series of formulae 
 of compounds, which by analogy he connects with indigo. 
 Thus:— 
 
 
 c. 
 
 H. 
 
 0. 
 
 H. 
 
 N. 
 
 Blue indigo (double atom) . 
 
 32 
 
 10 
 
 2 
 
 0 
 
 2 
 
 "White indigo . . 
 
 32 
 
 10 
 
 2 
 
 2 
 
 2 
 
 Acetyle .... 
 
 8 
 
 6 
 
 2 
 
 0 
 
 0 
 
 Aldehyde .... 
 
 8 
 
 6 
 
 2 
 
 2 
 
 0 
 
 Benzole .... 
 
 28 
 
 10 
 
 2 
 
 0 
 
 0 
 
 Oil of bitter almonds . 
 
 28 
 
 12 
 
 2 
 
 2 
 
 0 
 
 Cinnamole .... 
 
 36 
 
 14 
 
 2 
 
 0 
 
 0 
 
 Oil of cassia 
 
 36 
 
 14 
 
 2 
 
 2 
 
 0 
 
 Here we observe a series of compounds differing more widely 
 from each other than white and blue indigo, and only caused 
 by having two proportions more of hydrogen. A like analogy 
 is carried out between compounds of indigo with other bodies, 
 and compounds of other organic substances, which, however, 
 we must pass over. 
 
 Liebig's view of the reaction of indigo, and its relations to 
 other bodies, differs from that of Dumas. He considers, as 
 the result of careful and extensive investigation, that indigo 
 contains a salt radical (page 45) which he terms anyle , and 
 which is composed of C 16 H 5 N. This, it will be observed, is 
 indigo without any oxygen. He then considers that white 
 indigo is the hydrated protoxide of this base or radical, and 
 that blue indigo is the peroxide. Thus: — 
 
 C. H. ST. 0. Water. 
 
 Anyle 16 5 1 0 0 
 
 White indigo . . 16 5 1 1 1 
 
 Blue indigo. . . . 16 5 1 2 0 
 Taking double proportions for comparison: — 
 
 Anyle 32 10 2 0 0 
 
 White indigo . . . 32 10 2 2 2 
 
 Blue indigo. . . . 32 10 2 4 0 
 
INDIGO. 279 
 
 This view of the matter, which we think most consistent 
 with fact, and to which we may have occasion to return in 
 describing the vat, can be supported by analogies in the same 
 manner as the other view. Indeed, most of the coloring prin- 
 ciples of vegetables, such as madder, annotta, archil, &c, exist 
 in the plants as colorless bases, and become colored by the 
 absorption of oxygen. 
 
 M. Pressier, who has been very fortunate in his researches 
 into vegetable coloring matters and bases, thinks that he has 
 found a decisive argument in favor of Liebig's view, in the 
 fact that blue indigo, sugar, and potash react together, and 
 form white indigo. He therefore considers it very improbable 
 that indigo should extract hydrogen from water, at the same 
 time that the oxygen of the water would combine with the 
 hydrogen of the sugar to reproduce water. Dumas, however, 
 observed upon this, that there is no necessity for supposing 
 water to be decomposed, as the hydrogen of the sugar may 
 combine directly with the indigo blue and form indigo white. 
 These views of the question show that the subject is still one 
 of difficulty, and is full of interest; and that the daily expe- 
 rience of the dyer, were the results carefully observed, might 
 afford important aid towards the solution of some of those 
 vexed questions of chemical science. 
 
 If indigo be thrown into fused hydrate of potash, its blue 
 color disappears; it dissolves, and is partly decomposed along 
 with the water of the alkaline hydrate; hydrogen and ammo- 
 niacal gases are evolved, while carbonic acid, and another acid,, 
 named valerianic acid, having properties similar to acetic acid, 
 are formed, and combine with the potash. By digesting this 
 mixture with a little sulphuric acid, the alkali combines with 
 it, and the new acid crystallizes. This acid combines with 
 alkalies and other bases, and forms a very interesting series of 
 salts. 
 
 If indigo, in fine powder, be added to nitric acid, diluted 
 with seven or eight times its weight of water, and a gentle 
 heat be applied, it dissolves with effervescence, forming a yel- 
 low liquid. After standing a little, this liquid may be decanted 
 from any resinous matter formed during the process, and con- 
 centrated by evaporation, and speedily there will be found 
 deposited a quantity of yellowish- white crystals, having a 
 sourish-bitter taste, and requiring about 100 parts of cold 
 water for their solution. This was formerly termed indigotic 
 acid, but is now called anilic acid, from the species and name 
 of one of the plants which yield indigo. It combines with all 
 known bases, forming salts, which have generally a yellow 
 
280 
 
 INDIGO. 
 
 color. It gives a blood-red color to solutions of the persalts 
 of iron. 
 
 If indigo be added to strong nitric acid, and heat be applied, 
 it quickly dissolves, evolving a great quantity of nitrous gas. 
 On allowing the liquid to cool, a large quantity of semi-trans- 
 parent yellow crystals is formed having a very bitter taste. 
 This is what was, till lately, called carbazotic acid ; but this 
 name has been changed to picric acid. At the present time 
 picric acid is manufactured from carbolic acid, found in coal 
 tar. 
 
 To procure it in a purer state, the crystals obtained by the 
 above operation are to be washed in cold water, and then 
 boiled in water sufficient to dissolve them ; next filtering the 
 liquid and allowing it to cool. The acid again crystallizes in 
 brilliant yellow prisms. The acid may also be obtained by 
 the action of nitric acid upon anilic acid. 
 
 Picric acid is very permanent in its constitution. When 
 fused in chlorine or w T ith iodine it is not decomposed, nor does 
 a solution of chlorine affect it. Cold sulphuric acid has no 
 action upon it, but dissolves it when hot. Boiling hydro- 
 chloric acid does not act upon it, but nitromuriatic acid (aqua 
 regia) dissolves it with difficulty. It acts like a strong acid 
 upon metallic oxides, dissolving them and forming peculiar 
 crystallizable salts. These are yellow; they detonate strongly 
 when sharply heated, and also by percussion, particularly the 
 salt formed with potash. When a little of it is gradually 
 heated in a glass tube, it first fuses and then suddenly ex- 
 plodes, breaking the tube to pieces. Care is necessary in 
 making this experiment, as the fragments of glass may injure 
 the face. 
 
 This acid is an excellent test for the presence of potash in 
 any fluid ; a solution of it in alcohol producing a bright yellow 
 crystalline precipitate even in a diluted solution of the alkali. 
 It is thus more sensible than the chloride of platinum, com- 
 monly employed for the detection of potash ; for that re-agent 
 does not produce a precipitate in dilute solutions. 
 
 When indigo is acted upon by very diluted fuming nitric 
 acid, it unites with two atoms more of oxygen, and is conse- 
 quently converted into a new substance, which has received 
 the name of isatine. This substance, under the influence of 
 alkalies, absorbs one equivalent more of water, and assumes 
 an acid character, and is termed isatinic acid. This acid com- 
 bines with other substances, forming a series of compounds 
 the nature of which is not yet very well known. 
 
 Chromic acid has a similar action upon indigo as nitric acid. 
 
 When indigo in the dry state is brought into contact with 
 
INDIGO DYEING. 281 
 
 dry chlorine, no chemical action is observed; but when indigo 
 suspended in water is subjected to the action of chlorine, 
 several new products are formed. When the fluid thus acted 
 upon is distilled, a fluid product in minute quantity passes 
 over with the distilled water, and collects under it in the re- 
 ceiver in the form of white scales, which has been termed 
 chlorindoptin. It is sparingly soluble in water, but copiously 
 in alcohol. The substance which remains in the retort is found 
 to be a mixture of several new products. On being dissolved 
 in boiling alcohol, it yields, on cooling, red prismatic crystals 
 of a bitter taste and very insoluble in water; this has been 
 named chlorisatin. It dissolves in a solution of caustic potash, 
 producing a red color. The salts of lead give with this solu- 
 tion a yellow precipitate, which becomes a fine scarlet by 
 standing. The salts of copper (bluestone), &c, give a brown, 
 which becomes blood-red by exposure to the air. In the alco- 
 holic solution another substance is found, having an equiva- 
 lent more of chlorine than that named above; this is termed 
 bichlorisatin. Its properties, however, are analogous to those 
 of chlorisatin ; its solution in potash gives a yellow precipitate 
 with the salts of lead, but does not alter by exposure to the 
 air; and with the copper salts it gives a yellowish-brown, 
 which passes to blood-red. When chlorine is passed through 
 a solution of chlorisatin, another substance named chloronile is 
 formed. This crystallizes in scales of a brass-yellow color, and 
 when dissolved by potash gives a beautiful purple color. 
 
 If indigo in powder be added to a solution of caustic potash 
 of specific gravity 1.35 (70° Twaddell) and boiled, an orange- 
 yellow salt is formed. The solution of the boiled mass becomes 
 blue in the air from absorption of oxygen, like a solution of 
 white indigo, and blue indigo precipitates. 
 
 Besides the compounds resulting from the action of nitric 
 acid and chlorine upon indigo, there are several others which, 
 from their true characters being still little known, we have 
 not thought it necessary to enumerate. Some practical dyer 
 may indeed be inclined to ask what those already noticed have 
 to do with dyeing? We are sorry that, with respect to some 
 of them, we cannot give any satisfactory answer to the ques- 
 tion ; but the same question was asked when chemists first 
 intimated that chromic acid produced yellow salts when com- 
 bined with lead; yet this simple hint has completely revolu- 
 tionized various departments of dyeing, and the action of 
 chrome acid upon indigo, as already observed, has been both a 
 source of annoyance and advantage to the dyer. Previous to 
 the use of alkaline solutions of lead, dyers seldom could get 
 an evenly chrome green; the chromic acid being set at liberty 
 
282 
 
 INDIGO. 
 
 acted upon the indigo which was upon the yarn, destroying in 
 part the blue color, after which the green was all light-yellow 
 blains. These annoyances are still felt where the new process 
 of working the lead solution with an alkali is not practised. 
 But this same action of chromic acid upon indigo has been 
 taken advantage of by calico-printers, when they want a white 
 pattern on a blue ground. 
 
 Previous to the introduction of bichromate of potash for 
 this purpose, the calico-printers were ; to a certain extent, 
 limited. Thus : — 
 
 The pattern is printed upon the cloth with the oxide of a 
 metal which yields its oxygen easily to other substances, such 
 as copper and zinc; the goods are afterwards dyed blue by 
 passing them through the vat ; but the parts upon which these 
 metallic salts are printed, resist the dye, by yielding their 
 oxygen to the indigo, a process which will afterwards be de- 
 scribed, so that the piece when finished is a blue ground with 
 a white pattern. But after the blue vats have been wrought 
 for some time, they cannot be used for this purpose, owing to 
 the weakness of the dye, and the consequent length of time ne- 
 cessary to produce the required shade. So that these resist 
 pastes are in a manner washed off, and the pattern spoiled. 
 Now, in place of throwing out as useless vats thus exhausted, 
 as was formerly done, the cloth is dyed blue without resists, 
 and after being slightly scoured and washed, it is passed 
 through a strong solution of chromate of potash, and dried in 
 the shade ; the required pattern is then printed on the cloth 
 with a mixture of oxalic and tartaric acids made into a paste 
 by gum or clay. The potash in union with the chromic acid 
 is taken up by these acids, and the chromic acid being set at 
 liberty, acts on the indigo, and a white pattern is produced. 
 This ingenious process was discovered by a German chemist. 
 
 The following table exhibits the composition of those sub- 
 stances which we have briefly described as resulting from the 
 action of nitric acid and chlorine upon indigo. It may be 
 required for reference : — 
 
 Name. 
 
 c. 
 
 H. 
 
 0. 
 
 sr. 
 
 c. 
 
 Water. 
 
 Indigo .... 
 
 16 
 
 5 
 
 2 
 
 1 
 
 0 
 
 0 
 
 Isatine .... 
 
 16 
 
 5 
 
 4 
 
 1 
 
 0 
 
 0 
 
 Isatinic acid . 
 
 16 
 
 5 
 
 4 
 
 1 
 
 0 
 
 l 
 
 Anilic, or indigotic acid . 
 
 14 
 
 4 
 
 9 
 
 1 
 
 0 
 
 i 
 
 Picric, or carbazotic acid 
 
 12 
 
 2 
 
 13 
 
 3 
 
 0 
 
 i 
 
 Chlorindoptin 
 
 16 
 
 4 
 
 2 
 
 0 
 
 4 
 
 0 
 
 Chlorisatin 
 
 16 
 
 4 
 
 3 
 
 1 
 
 1 
 
 0 
 
 Bichlorisatin . 
 
 16 
 
 4 
 
 3 
 
 1 
 
 2 
 
 0 
 
 Chloranile 
 
 6 
 
 0 
 
 2 
 
 0 
 
 2 
 
 0 
 
 Valerianic acid 
 
 10 
 
 9 
 
 3 
 
 0 
 
 0 
 
 1 
 
SULPHO-PURPURIC ACID. 
 
 283 
 
 The only substance which dissolves indigo, without destroy- 
 ing its color and composition, is highly concentrated sulphuric 
 acid. For this purpose the fuming acid of Nordhausen is pre- 
 ferable (page 96), as when other acid is used, a greater quan- 
 tity of it is required. The substance formed is popularly 
 known by the names of sulphate of indigo, Saxon blue, China 
 blue, and extract of indigo. The action of sulphuric acid upon 
 indigo is found to be something more than a mere solution ; a 
 chemical combination, in definite proportions, results, forming 
 two distinct substances, differing considerably from each other 
 in their properties. These two compounds were discovered 
 and described by Mr. Crum, and called by him cerulin and 
 phinacin t from their colors — the former blue, and the latter 
 purple. They have since been named sulph-indylic acid, and 
 sulpho-purpuric acid. The former, which constitutes the blue 
 principle of Saxon blue, is formed most abundantly when the 
 sulphuric acid is sufficiently strong and abundant, and other 
 proper means attended to. Its composition is found to be one 
 atom of indigo combined with two of sulphuric acid. The 
 other is the principal product when the indigo preponderates. 
 
 It is of a purple color ; and when the solution is diluted with 
 water, it precipitates. Its composition is found to be equal to 
 one atom of indigo to one of sulphuric acid. 
 
 From the nature and properties of these two substances, it 
 is evident that every care should be taken to convert the in- 
 digo into sulph-indylic acid, and to avoid the formation of 
 sulpho-purpuric acid. The circumstances under which this 
 latter acid is formed are — first, too little acid in proportion to 
 the indigo, and secondly, too little time allowed for digestion. 
 The general proportions used by dyers vary from three to five 
 pounds of acid to the pound of indigo. This is by far too lit- 
 tle, and occasions a considerable loss of indigo by the precipi- 
 tation of the sulpho-purpuric acid, when the solution is diluted 
 with water. Close observation shows that it requires from six 
 to eight pounds of concentrated sulphuric acid to convert a 
 pound of indigo into blue sulph-indylic acid. From some in- 
 vestigations lately made by M. Dumas, indigo requires even a 
 larger proportion of acid to convert it into sulph-indylic acid. 
 He recommends no less than fifteen parts of acid to one of in- 
 digo. This quantity, however, we have found to be of no 
 advantage in practice, but rather the opposite, particularly when 
 the acid is to be neutralized before the indigo solution is used, 
 which is the general custom in dyeing cotton. 
 
 We have said that the second circumstance under which 
 sulpho-purpuric acid is formed is that of too short time being 
 given for the indigo and acid to digest. When indigo is first 
 
284 
 
 INDIGO. 
 
 put into the sulphuric acid, there seems to be an immediate 
 solution ; but if a drop be spread upon a window-pane, it 
 appears of a dirty-green color ; and if allowed to stand for a 
 little upon the glass, a yellowish-colored liquid begins to run 
 from the blue mass, occasioned, no doubt, by the acid absorb- 
 ing moisture, and separating itself from the indigo, and clearly 
 showing that the change upon the indigo by the acid is not an 
 immediate effect. The more impure the indigo, the darker and 
 greener appears the substance when put upon the glass. After 
 the mixture has stood two or three hours, and being tried in 
 the same manner, it appears of a reddish-purple color — the 
 principal compound existing now in the solution being sulpho- 
 purpuric acid. As the liquid stands, it begins to assume a 
 violet shade, and finally passes to a deep rich blue. But dyers 
 seldom obtain it in this state ; in their hands it generally has a 
 reddish tinge. Mr. Crum found that when the solution is 
 diluted with water, after the color has become of a bottle-green, 
 the action of the acid is stopped, and sulpho-purpuric acid only 
 is formed. But there are other means by which the action of 
 sulphuric acid upon indigo may be stopped, than by directly 
 diluting the solution with water. As already intimated, it is 
 only the highly concentrated sulphuric acid which converts in- 
 digo into sulph-indylic acid. Now, dyers not unfrequently 
 alter the strength of their acid by the process of mixing and 
 preparing their chemtc (the technical name for sulphate of in- 
 digo). This is very generally done in an open wide-mouthed 
 vessel, which is allowed to stand uncovered, probably in the 
 midst of the steam and vapors of the dye-house ; or, in some 
 cases, the vessel is put into a boiler, or tub with boiling water. 
 By these injudicious means, the sulphuric acid which absorbs 
 water very rapidly, is diluted below the necessary strength 
 for dissolving indigo ; and the result is the formation of sulpho- 
 purpuric acid, instead of sulph-indylic acid, which is the real 
 substance wanted. 
 
 Another cause of the stopping of the action of the acid by 
 dilution is from the indigo. Ground indigo absorbs a quan- 
 tity of moisture; and if it be not thoroughly dried previous to 
 putting it in the acid, the acid is too much weakened to effect 
 the formation of the substance required. 
 
 There are other causes by which the preparation of chemic is 
 injured. Sometimes the acid and indigo are mixed together 
 at once, and by this means the heat evolved is sufficient to de- 
 compose the impurities of the indigo. Part of the acid also 
 suffers decomposition, and a great quantity of sulphurous acid 
 gas is given off — so much, indeed, that the head cannot be 
 held above the vessel for any length of time without injury. 
 
SULPHATE OF INDIGO. 
 
 285 
 
 Another practice is, for the sake of quickening the operation, 
 to place the vessel upon the flue in the stove, and keep the 
 solution for hours at a heat upwards of 300° Fah. The gas 
 given off in these cases is sometimes so great as to destroy the 
 colors of goods hanging in the stove. Indigo submitted to such 
 treatment is seldom found good ; often its appearance on white 
 paper or glass (which is a general method of testing the quality 
 of sulphate of indigo) is a blackish-green — sometimes a dirty 
 purple — seldom the fine blue violet — scarcely ever the beau- 
 tiful blue. 
 
 Although the sulpho-purpuric acid is precipitated when 
 water is mixed with the solution of sulphate of indigo, and is 
 insoluble in dilute acids, it is, when freed from the sulphuric 
 acid, soluble in distilled water; but if any substance be in 
 the water — and common spring water is never pure — it is less 
 soluble. It dissolves in alkalies, and in solutions of the alka- 
 line earths, giving a blue color, of greater or less purity, ac- 
 cording to the nature of the solvent. 
 
 We have found the following method of preparing sulphate 
 of indigo, in quantities for use, very satisfactory : The indigo 
 is reduced to an impalpable powder, either by grinding in a 
 mortar or a mill, and completely dried, by placing it upon a 
 sand-bath or flue for some hours, at a temperature of about 
 140° or 150° Fah. For each pound of indigo, six pounds of 
 highly concentrated sulphuric acid are put into a large jar, or 
 earthen pot, furnished with a cover. This is kept in as dry a 
 part as possible, and the indigo is added gradually, in small 
 quantities. The vessel is kept closely covered, and care taken 
 that the heat of the solution does not exceed 212° Fah. When 
 the indigo is all added, the vessel is placed in such a situation 
 that the heat may be kept at about 150° Fah., and allowed to 
 stand, stirring occasionally, for forty-eight hours. These pre- 
 cautions being attended to, we have uniformly found that any 
 failure occurring was clearly traceable to impurity of the indigo 
 or weakness of the acid used. 
 
 The dyer now very seldom prepares his own sulphate of in- 
 digo; it is manufactured for him, and sold in the market as 
 indigo extract, which, when properly prepared, is a superior 
 article to that prepared by himself. The following is the pro- 
 cess of its manufacture: The indigo is dissolved in the sul- 
 phuric acid as described ; it is then diluted with hot water — 
 distilled water is best; the whole is put upon a filter of woollen 
 cloth, by which means the insoluble impurities of the indigo 
 are separated. The blue solution which has passed through 
 the filter is transferred to a leaden vessel, and evaporated till 
 reduced to about three gallons for every pound of indigo used. 
 
286 
 
 INDIGO. 
 
 There is then added about 4 lbs. of common salt to the pound 
 of indigo, and the whole is well stirred. The sulpho indylic 
 acid is thus precipitated, and the whole is again thrown upon 
 a similar filter of woollen cloth; the extract remains upon the 
 filter, and, when sufficiently drained, is ready for the market. 
 Some makers add a little potash or soda, which may be ad- 
 vantageous, and a little ammonia gives the extract a beautiful 
 bloom. A pound weight of good indigo should yield 14 lbs. 
 of extract. The adulterations in this solution are various. 
 Some of the insoluble matter is occasionally added, bat not 
 often, as it deteriorates the appearance of the extract. The ad- 
 dition of a little lime or barytes gives an insoluble precipitate, 
 which adds weight to the extract; but all practices of that 
 kind react upon the maker ; for, although the dyer may not 
 have methods of testing his stuff, he very soon ascertains its 
 working value by experience. 
 
 The extract of indigo is used in the dye-house in the same 
 way as the sulphate was used before this method of preparation 
 was adopted. The general term of chemic is applied to both, 
 and chemic blue is used in various operations. For dyeing 
 silks and woollens blue, the extract is simply diluted, and the 
 goods merely passed through it ; but this method cannot be 
 adopted with cotton, as its fibres have no affinity for sulphate 
 of indigo. But although not used for dyeing blue upon cot- 
 ton, it is extensively used for dyeing green upon light goods 
 of that material. When the cloth is dried from the sulphate 
 of indigo solution, the acid of the chemic must be neutralized ; 
 for this purpose the chemic is prepared differently. The ex- 
 tract is put into hot water — the exact quantity is not material — 
 and well stirred ; to this solution a quantity of pounded chalk 
 or whiting is added gradually, until the acid is exactly neu- 
 tralized ; this is a nice operation, and requires great care on the 
 part of the operator; for, were the acid property to prevail in 
 the least, it would destroy the yellow upon the cloth to be dyed 
 green; and were the alkaline matter predominant, it would 
 brown the yellow, and the green would assume a blackish- 
 olive shade. Thus the beauty of the colors depends upon the 
 dyer being careful to stop just at the turning point. The only 
 method employed by dyers for determining the point of neu- 
 trality is the taste; and this, from many circumstances which 
 we need not enumerate, is liable to error; and when the dyer 
 is deceived, the results are very annoying, and also expensive. 
 Were very delicately prepared blue and red litmus-papers 
 used, the results would be much more certain. However, the 
 reader may be astonished when we inform him, that the failures 
 from this source are very seldom. Some dyers use carbonated 
 
THE BLUE VAT. 
 
 287 
 
 alkalies, such as soda and potash, to neutralize their acid ; and 
 no doubt when any of these are used, the sediment at the bot- 
 tom is much less; but we have always thought that owing to 
 the salts formed by these alkalies being dissolved in the blue 
 solution, the green color is not so good, especially when bark 
 is the yellowing substance. 
 
 The process of dyeing greens by this sort of prepared chemic 
 is as follows: The goods, after being well boiled and washed, 
 are put through a dilute solution of pyrolignite of alumina of 
 specific gravity 1.035, that is 7° of Twaddell, and washed from 
 this through hot water; they are then wrought through a de- 
 coction of quercitron bark, or jlavine. When sufficiently yellow 
 for the shade of green required, they are then wrought through 
 a quantity of chemic mixed with cold water, wrung from this 
 and dried. If fustic is the yellowing substance used, alum is a 
 better mordant. 
 
 The greater portion of the indigo imported is used for dye- 
 ing blue by means of the blue vat. We have already men- 
 tioned that indigo is insoluble, except in strong sulphuric acid; 
 but if it be by any means deprived of an atom of oxygen (ac- 
 cording to the common theory), it is soluble in alkalies. It 
 may be said that, according to the law of definite proportions 
 described in our first article, it cannot be indigo with an atom 
 less of oxygen. Neither is it; and we see that it has different 
 properties from common indigo, for it is soluble even in weak 
 alkalies; has a powerful attraction for oxygen; and is of a white 
 color. This substance has been termed indigogen, and it may 
 be observed, that the nature of the blue vat depends upon the 
 introduction of substances capable of extracting oxygen from 
 the indigo, and converting it into indigogen. The substances 
 generally used for this conversion are the protoxides of iron 
 and tin, orpiment (sulphuret of arsenic), and organic substances. 
 These last produce the desired effect by their decomposition, 
 such as in the woad vat, where, by the fermentation of the 
 woad and madder, the oxygen is extracted from the indigo, 
 which is thus converted into indigogen. The indigogen is dis- 
 solved, as it forms, by the potash put into the vat. 
 
 What is termed the common blue vat, or lime vat, is made 
 up with indigo, lime, and sulphate of iron (copperas). But 
 before describing the nature of this vat it will be necessary, at 
 the risk of a little repetition, to refer to the properties of oxide 
 of iron (page 152). 
 
 The protoxide of iron, especially when in contact with mois- 
 ture, has a strong attraction for more oxygen so as to pass into 
 the peroxide. When the sulphuric acid of copperas is neutral- 
 ized by an alkali, the iron is left in the state of a protoxide. 
 
288 
 
 INDIGO. 
 
 The blue vat is made up by putting lime, copperas, and indigo 
 into a vessel filled with water, and stirring occasionally for a 
 day or two, when the indigo is dissolved. Thus: When finely 
 ground indigo is put into a vat with a mixture of lime and 
 sulphate of iron, the first action which takes place is the de- 
 composition of the metallic salt; the acid, which is in union 
 with the iron, combining with a portion of the lime, forms sul- 
 phate of lime and oxide of iron. The detached oxide of iron 
 extracts more oxygen from the indigo, converting it into indi- 
 gogen (white indigo), and the peroxide of iron and the sulphate 
 of lime thus formed are precipitated, forming what is technically 
 termed sludge. The remaining portion of lime dissolves the in- 
 digogen, and forms with it the solution required. The follow- 
 ing diagram represents this action and the result more clearly, 
 and gives one view of the theory of the blue vat: — 
 
 J Indigogen 
 (Oxygen 
 
 Indigo, composed of 
 
 f Oxide of iron - 
 J Oxide of iron 
 Sulphuric acid 
 Sulphuric acid 
 
 ( Lime 
 
 3 Lime •< Lime 
 
 2 Copperas 
 
 Dyeing solution. 
 
 Peroxide of iron. 
 
 ( Lime . 
 
 Sulphate of lime. 
 Sulphate of lime. 
 
 It will be observed that this theory of the vat is founded on 
 blue indigo being an oxide; but, according to the view which 
 Dumas takes of the constitution of indigo, the action which 
 takes place in the vat will be somewhat different from that 
 given above. When the lime combines with the acid of the 
 copperas, the iron decomposes a portion of water, combining 
 with the oxygen, and the hydrogen combines with the indigo 
 forming indigogen, which may be represented as follows: — 
 
 Indigo . 
 Water . 
 
 3 Lime. 
 
 2 Copperas. 
 
 . Indigo 
 
 J Hydrogen. . . . 
 
 (Oxygen 
 
 (Lime 
 
 -< Lime 
 
 (Lime 
 
 [ Oxide of iron. 
 J Oxide of iron. 
 J Sulphuric acid 
 [ Sulphuric acid 
 
 Indigogen, forming dyeing 
 solution. 
 
 Peroxide of iron. 
 Sulphate of lime. 
 Sulphate of lime. 
 
 This theory is equally, if not more beautiful, than the former, 
 but in some cases it is scarcely reconcilable with our chemical 
 experience. When the goods are put into the vat, the dissolved 
 
THEORY OF THE BLUE VAT. 
 
 289 
 
 indigogen combines with them, and when brought into contact 
 with the air, according to the former theory, the indigogen 
 combines with oxygen, for which it has a strong affinity 
 and blue indigo is formed, and remains combined with the 
 cloth; but, according to the latter theory, the blue indigo is 
 left in combination with the cloth by the hydrogen combining 
 with the oxygen of the atmosphere, and forming water. The 
 supposition that hydrogen should combine with the free oxygen 
 of the air, and form water so rapidly under such circumstances 
 as mere exposure, is somewhat anomalous, but this is no reason 
 for rejecting it. If a mixture of copperas and lime be put 
 into a bottle with distilled water, the water is not decomposed ; 
 the lime combines with the acid, which, along with the iron, is 
 precipitated, and if the air be completely excluded, the iron 
 remains as a protoxide, for days ; indeed, the change from a 
 protoxide to a peroxide is so slow, that a long time elapses 
 before it is appreciable; but if indigo be added, even after the 
 mixture has stood for some time, the action of the common vat 
 proceeds. This, according to Dumas's theory, gives a beautiful 
 illustration of relative affinities. Before the indigo is introduced, 
 the attraction of the iron for oxygen is about equal to that of 
 the hydrogen, which holds it in combination as water, but when 
 the indigo is introduced, although its attraction for hydrogen 
 must be very weak, as it requires the nicest management to get 
 that compound isolated, still it is sufficient to disturb the equi- 
 librium with which the oxygen was held by the iron and hydro- 
 gen, giving the former the mastery. Whether the presence of 
 an alkaline substance has any effect of inducing, if we be 
 allowed the term, the formation of indigogen, we cannot pre- 
 tend to determine; but it is never formed in the vat without 
 the presence of some alkaline substance to dissolve it the 
 moment it is formed. This circumstance also explains that the 
 alkali having also an affinity for indigogen, may assist the 
 reaction in the vat. 
 
 We would recommend the reader to reperuse the remarks 
 upon the salts of iron, in connection with these on the blue vat, 
 in order that he may be better able to appreciate them, and 
 especially to understand what ought to be the properties of 
 good copperas from the part it is required to play in the vat; 
 also why it is that the quality of the copperas makes so great 
 a difference in the working of a blue vat. 
 
 There is one serious annoyance often experienced in working 
 the vat, technically called swimming ; that is, the precipitate 
 not settling down, the goods come in contact with it to the 
 serious injury of the color. This may be occasioned by several 
 circumstances. Should the copperas have an excess of acid, 
 19 
 
290 
 
 INDIGO. 
 
 either from its being crystallized out of an acid solution, or from 
 its having sulphate of alumina in it (as described at page 155), 
 it will form a sulphate of lime, which will not precipitate so 
 quickly as that formed by the decomposition of the copperas ; 
 but the prevailing cause of a floating vat is excess of iron and 
 lime. Let the dyer take a solution of copperas or protosul- , 
 phate of iron, and one of persulphate, and add to each a suffi- 
 cient quantity of lime to precipitate the iron, he will find that 
 the peroxide of iron will precipitate rapidly and completely, 
 and that the protoxide will precipitate slowly and incompletely. 
 The same phenomenon takes place in the vat when lime and 
 copperas are added ; sulphate of lime and protoxide of iron 
 are formed, and if there be not enough of indigo to convert 
 the protoxide of iron to the state of peroxide — in which state 
 it precipitates easily — the protoxide will remain floating for a 
 long time. Hence the floating vat — the only cure for which 
 is the addition of a little indigo, or of a substance that will 
 peroxidize the iron. When vats become weak, great care 
 should be taken not to add an excess of copperas. We have 
 seen a little soda added to a floating vat as a cure, and if the 
 evil consisted in the quantity of the copperas, this mode of cure 
 might be successful, but not otherwise. A floating vat is 
 sometimes caused by using improper lime. When slaked lime 
 lies exposed for a short time to the air, and more especially in 
 a work such as a dye-work, it absorbs carbonic acid, and be- 
 comes converted into chalk, and this put into the vat is very 
 deleterious in other respects, besides causing swimming. The 
 lime used for the vat should always be newly slaked. This is a 
 necessary precaution, as the practice is too often otherwise that 
 is here recommended. 
 
 When the paucity of indigo in the last stages of a vat causes 
 floating, a small portion of a copper salt may be of service, as 
 this oxide will give up a part of its oxygen to the iron, becom- 
 ing a suboxide; or it will oxidate a portion of the indigo in 
 solution, and this would react in turn upon the iron. The 
 property of this and some other metals for neutralizing the 
 effects of iron in the vat has already been noticed ; but it may 
 be more apparent by thus referring to it- here, and it may be 
 still farther enforced in connection with that branch of calico- 
 printing called resist work, indicated at page 282, and which 
 may be thus further described : A certain preparation, the best 
 we believe is the sulphate of copper or zinc, is mixed either 
 with flour paste, with gum, or w r ith pipe-clay and gum, and 
 printed on the calico, of any pattern that may be desired ; when 
 this is sufficiently dry, the goods are dyed in the blue vat ; 
 
THE BLUE VAT. 
 
 291 
 
 those parts of the piece which are printed with the copper or 
 zinc will not be dyed blue, because the deoxidized indigo be- 
 comes oxygenated the moment it touches the copper, which 
 yields its oxygen to the indigo, and occasions it to become 
 insoluble, and consequently incapable of forming a dye. Ac- 
 cording to Dumas's theory, the hydrogen, in combination with 
 the indigo, unites with the oxygen of the copper and forms 
 water — the results are alike in both. 
 
 Before concluding this article, we may inform the general 
 reader that, in print-works and dye-houses, where piece-goods 
 are dyed blue, the vats are necessarily large, being generally 
 about three feet wide by five feet long, and eight feet deep, 
 made of iron, but sometimes of stone; and are sunk into the 
 ground about half their depth. The goods to be dyed are 
 stretched upon a frame, when the whole is lowered into the vat. 
 Sometimes these frames are furnished with rollers, when, instead 
 of fixing the piece on hooks, it is passed over these rollers while 
 in the vat, by which means long pieces are dyed perfectly 
 regular in color. 
 
 The vats for yarn or skein are small, being generally old 
 wine or oil-pipes ; these are also sunk about half their depth 
 into the ground. Wooden pins are put through the skein, and 
 rest upon the edge of the vat; the skein is then turned over, 
 the one half dipping in the liquor, the other half over the pins. 
 The time of this operation varies according to the strength of 
 the vat. The operation being continued some time, the skein 
 is taken out, wrung, and exposed to the air, dipped again, and 
 so on, alternately dipping and exposing, till the requisite shade 
 is obtained. 
 
 To prepare the vat, it is filled to within a few inches of the 
 mouth with water ; the dyeing ingredients are then added. The 
 proportions given in most chemical books are 1 part (by weight) 
 indigo, 2 parts sulphate of iron, and 3 parts lime: but this pro- 
 portion of lime is too much ; the practical dyer does not con- 
 sider his vats in good condition when this proportion is used. 
 The following proportions are considered proper for preparing 
 one of these small vats — assuming all the ingredients good : 8 
 pounds of indigo, 14 pounds of copperas, and from 18 to 20 
 (not above 20) of lime. If the copperas be bad, a pound or 
 even 2 pounds more of it may be required, together with 2 or 3 
 additional pounds of lime, to produce the same result. These in- 
 gredients being put in, the whole is well stirred every two or 
 three hours during the day, and, after settling for twelve hours, 
 the vat is ready for use. 
 
 The chemical equivalents of lime may be calculated from the 
 
292 
 
 INDIGO, 
 
 table of elements, and also the rate of combination. Thus, 
 slaked lime is the hydrated oxide of calcium: — 
 
 Lime 
 Water 
 
 Ca 
 
 = 20 
 
 0 
 
 = 8 
 
 H 
 
 
 0 
 
 = 8 
 
 
 37 
 
 Fe 
 
 = 28 
 
 And again we have — 
 
 C °PP eras Is6 4 =48 
 Water of crystallization 7 HO = 63 
 
 139 
 
 Thus by equivalents, 37 lbs. of slaked lime should neutralize 
 139 lbs. of crystals of copperas; but, as 77 gallons of water at 
 60° can dissolve only one pound of lime, it is easy to see how 
 few pounds are required above the equivalent for copperas to 
 form the lime solution of the vat to dissolve the indigogen. 
 How it is that practice dictates such a quantity of lime to be 
 used, is deserving of inquiry ; we merely hint that it may be 
 that the compound of indigogen and lime is more soluble than 
 lime alone. 
 
 Woad and Pastel. — We have already alluded to these 
 vegetables as yielding a variety of indigo which has been long 
 used for dyeing woollen goods. It is still extensively used for 
 that purpose, especially on the continent ; and as a description 
 of the process as it is there followed out may be interesting to 
 many of our readers, we extract the following from Dumas's 
 Lectures on Dyeing, slightly altered from the translation in the 
 Pharmaceutical Times :— 
 
 " Indigo Blue. — We give a solid dye of indigo blue to wool 
 by plunging it into an alkaline solution of indigo white, and 
 then exposing it to contact with the air. The solution of in- 
 digo white is prepared in a vessel usually from eight to nine 
 feet in depth, and six to seven feet in diameter. This size is 
 very convenient for the requisite manipulations, and presents a 
 large volume of water, which, when once heated, is capable of 
 preserving a high temperature for a long time. This vessel 
 should be made of wood or copper. It always bears the name 
 of vat. These vats are covered with a wooden lid, divided 
 into two or three equal segments. Over this lid are spread 
 some thick blankets. Without this precaution the bath would 
 come in contact with the atmospheric air; a portion of the 
 
WOAD AND PASTEL. 
 
 293 
 
 indigo would absorb oxygen and become precipitated. There 
 would also be a great waste of heat. 
 
 " A most necessary operation, and one which has to be fre- 
 quently repeated, consists in stirring up the deposit of vegetable 
 and coloring matter which is formed in the vat, and intimately 
 mixing it in the bath. For this purpose we employ a utensil 
 called a rake, which is formed of a strong square piece of wood, 
 set on a long handle. The workman takes hold of this with 
 both hands, and, dipping the flat surface into the deposit at the 
 bottom of the vessel, he quickly draws it up until it nearly 
 reaches the surface, when, giving it a gentle shake, he dis- 
 charges the matter again through the liquor of the bath. This 
 manoeuvre is repeated until the whole of the deposit seems to 
 be removed from the bottom of the vessel. Before the tissue 
 is dipped into the dye-bath, it should be soaked in a copper 
 full of tepid water; it is then to be hung up and beaten with 
 sticks. In this state it is plunged into the vat ; it thus intro- 
 duces less air into the bath, while it is more uniformly pene- 
 trated by the indigo solution. The cloth is now kept at a 
 depth of from two to three feet below the surface of the liquid, 
 by means of an open bag or piece of network fixed in the in- 
 terior of an iron ring, which is suspended by cords, and fixed 
 to the outside of the vat by means of two small iron hooks ; 
 the bag is thus drawn backwards and forwards without permit- 
 ting it to come in contact with the air. When this operation 
 has been continued for a sufficient length of time, the cloth is 
 wrung and hung up to dry. 
 
 " Flock wool is also, for the purpose of dyeing, inclosed in 
 a fine net, which prevents the least particle from escaping, and 
 which is fixed in the bath in the same way as in the foregoing 
 case. 
 
 "The many inconveniences attending the use of wooden 
 baths, which necessitate the pouring of the liquor into a copper 
 for the purpose of giving it the necessary degree of heat, have 
 led to the general employment of copper vessels. These are 
 fixed in brickwork, which extends half way up their surface, 
 whilst a stove is so constructed at this elevation that the flame 
 shall play around their upper part. By this means the bath 
 is heated and kept at a favorable temperature without the 
 liquor being obliged to be removed. 
 
 u The potash vats are usually formed of conical -shaped cop- 
 pers, surrounded by a suitable furnace. These may be con- 
 structed with less depth, inasmuch as there is less precipitation 
 induced in the liquor. By using steam for heating the vats, 
 we might dispense with the employment of copper vessels, and 
 so return to those of wood. 
 
29i 
 
 INDIGO. 
 
 u The vats employed for dyeing wool are known under the 
 names of the pastel vat, the woad vat, the potash vat, the Tartar 
 lee vrat, and the German vat. 
 
 " The pastel is cultivated in France, Piedmont, England, and 
 Saxony. It is distinguished into several varieties, according 
 to the localities in which it is grown. We have already stated 
 that the pastel contains a blue coloring matter identical with 
 indigo, and a fawn-colored yellow matter, which may easily be 
 separated by treating the pastel balls by hot water before the 
 fermentative process is established. The woad is cultivated in 
 Normandy ; it contains less coloring matter, whether blue or 
 yellow, than the pastel ; its durability is also inferior to that 
 of the last named substance. M. Chevreul has given an analy- 
 sis of the pastel, which will tend to throw some light upon 
 its use. 
 
 "When the leaves are subjected to the action of the press, 
 we obtain, on the one hand, a residue of a ligneous nature, and, 
 on the other, a juice which holds in suspension sundry matters 
 which give it a cloudy appearance. Thrown on a filter, it 
 leaves a greenish matter or fecula, which is formed of chloro- 
 phylle, wax, indigo blue, and an azotized* substance. The 
 clear liquid, after passing through the filter, contains an azot- 
 ized substance coagulable by heat; an azotized substance non- 
 coagulable by heat; a red matter, resulting from the union of 
 the blue coloring principle with an acid; a yellow principle; 
 gummy matter; some liquid sugar; a fixed organic acid; free 
 acetic acid and acetate of ammonia; the odorous principle of 
 the cruciferae; a volatile principle, having the odor of osma- 
 zome; citrate of lime; sulphates of lime and potash; phosphates 
 oflime; magnesia, iron, and manganese; nitre, and chloride of 
 potassium. 
 
 U M. Chevreul has not discovered in these products any body 
 possessed of the power of seizing upon oxygen in an energetic 
 manner, and which would explain the action of the pastel in 
 the indigo vat. Still we cannot doubt that the principles fur- 
 nished by this matter intervene, to a certain extent, as combus- 
 tibles, and that we must refer at least a part of their effect. to 
 this mode of action. The indigo should itself be selected with 
 care. The Guatimala variety is preferred for the urinary or 
 Indian vat, and the Bengal indigo for the pastel vat. 
 
 "Pastel Yat. — The first care of the dyer in preparing the 
 vat should be to furnish the bath with matters capable of com- 
 bining with the oxygen, whether directly or indirectly, and of 
 giving hydrogen to the indigo. We must, however, be careful 
 
 * Azote is a synonyme of nitrogen. 
 
THE PASTEL VAT. 
 
 295 
 
 to employ those substances only which are incapable of impart- 
 ing to the bath a color which might prove injurious to the in- 
 digo. These advantages are found in the pastel, the woad, and 
 madder. This latter substance furnishes a violet tint when 
 brought into contact with an alkali, and by the addition of in- 
 digo it yields a still deeper sha^e. 
 
 M In preparing the Indian vat, we ordinarily employ one 
 pound of fine madder to two pounds of indigo. The madder is 
 here especially useful, by reason of the avidity of some of its 
 principles for oxygen. 
 
 " The pastel vat, when prepared on a large scale, ordinarily 
 contains from 18 to 22 lbs. of indigo; 11 lbs. of madder would 
 suffice for this proportion, but we must also bear in mind the 
 large quantity of water which we have to charge with oxidiza- 
 ble matters. I have invariably seen the best results from em- 
 ploying 22 lbs. to a vat of this size. Bran is apt to excite the 
 lactic fermentation in the bath, and should therefore not be 
 employed in too large a quantity; 7 to 9 lbs. will be found 
 amply sufficient. 
 
 "The weld is rich in oxidizable principles; it turns sour, 
 and passes into the putrid fermentation with facility. Some 
 dyers use it very freely; but ordinarily we employ in this bath 
 an equal quantity of it to that of the bran. Sometimes weld 
 is not added at all. 
 
 "In most dye-houses the pastel is pounded before introducing 
 it into the vat. Some practical men, however, maintain that 
 this operation is injurious, and that it interferes with its dura- 
 bility. This is an opinion which deserves attention. The effect 
 of the pastel, when reduced to a coarse powder, is more uniform ; 
 but this state of division must render its alterations more rapid. 
 When the bath has undergone the necessary ebullition, the 
 pastel should be introduced into the vat, the liquor decanted, 
 and, at the same time, 7 or 8 lbs. of lime added, so as to form 
 an alkaline lye which shall hold the indigo in solution. Hav- 
 ing well stirred the vat, it should be set aside for four hours, 
 so that the little pellets shall have time to become thoroughly 
 soaked, both inside and out, and thus be prepared for fermen- 
 tation. Some think coverings are to be spread over the vat, 
 so as to preserve it from contact with the atmosphere. After 
 this lapse of time, it is to be again stirred. The bath at this 
 moment presents no decided character; it has the peculiar odor 
 of the vegetables which it holds in digestion ; its color is of a 
 yellowish-brown. 
 
 Ordinarily, at the end of twenty-four hours, sometimes even 
 after fifteen or sixteen, the fermentative process is well marked. 
 The odor becomes ammoniacal, at the same time that it retains 
 
296 
 
 INDIGO. 
 
 the peculiar smell of the pastel. The bath, hitherto of a brown 
 color, now assumes a decided yellowish-red tint. A blue froth, 
 which results from the newly liberated indigo of the pastel, 
 floats on the liquor as a thick scum, being composed of small 
 blue bubbles, which are closely agglomerated together. A 
 brilliant pellicle covers the bath, and beneath we may perceive 
 some blue or almost black veins, owing to the indigo of the 
 pastel which rises towards the surface. If the liquor be now 
 agitated with a switch, the small quantity of indigo which is 
 evolved floats to the top of the bath. On exposing a few drops 
 of this mixture to the air, the golden yellow color quickly dis- 
 appears, and is replaced by the blue tint of the indigo. This 
 phenomenon is due to the absorption of the oxygen of the air 
 by the indigogen from the pastel ; in this state we might even 
 dye wool with it without any further addition of indigo; but 
 the colors which it furnishes are devoid of brilliancy and 
 vivacity of tone, at the same time that the bath becomes 
 quickly exhausted. 
 
 "The signs above described announce, in a most indubita- 
 ble manner, that fermentation is established, and that the vat 
 has now the power of furnishing to the indigo the hydrogen 
 which is required to render it soluble — that contained in the 
 pastel having been already taken up; this, then, is the proper 
 moment for adding the indigo, which should be previously 
 ground in a mill. 
 
 "We stated above that the liquor of the vat should be pre- 
 viously charged with a certain quantity of lime; we also find 
 in it ammonia generated by the pastel; but a part of these 
 alkalies become saturated by the carbonic acid gas along with 
 the proper acids of the madder and of the weld, as well as by 
 the lactic acid produced by the bran during fermentation. 
 The ordinary guide of the dyer is the odor, which, according 
 to circumstances, becomes more or less ammoniacal. The vat 
 is said to be either soft or harsh ; if soft, a little more lime 
 should be added to it. The fresh vat is always soft; it exhales 
 a feeble ammoniacal odor accompanied with the peculiar smell 
 of the pastel; we must, therefore, add lime to it along with 
 the indigo; we usually employ from five to six pounds, and, 
 after having stirred the vat, it is to be covered over. The 
 indigo, being incapable of solution except by its combination 
 with hydrogen, gives no sign of being dissolved until it has 
 remained a certain time in the bath. We may remark that 
 the hard indigoes, as those of Java, require at least eight or 
 nine hours, whilst those of Bengal do not need more than six 
 hours, for their solution. We should examine the vat again 
 three hours after adding the indigo. We ordinarily remark 
 
WOAD VAT. 
 
 297 
 
 that the odor is by this time weakened ; we must now add a 
 further quantity of lime, sometimes less, but generally about 
 equal in amount to the first portion; it is then to be covered 
 over again, and set aside for three hours. 
 
 u After this lapse of time, the bath will be found covered 
 with an abundant froth and a very marked copper-colored 
 pellicle; the veins which float upon its surface are larger and 
 more marked than they were previously; the liquor becomes 
 of a deep yellowish-red color. On dipping the rake into the 
 bath, and allowing the liquid to run off at the edge, its color, 
 if viewed against the light, is of a strongly-marked emerald- 
 green, which gradually disappears, in proportion as the indigo 
 absorbs oxgen, and leaves in its place a mere drop rendered 
 opaque by the blue color of the indigo. The odor of the vat 
 at this instant is strongly ammoniacal; we also find in it the 
 peculiar scent of the pastel. When we discover a marked 
 character of this kind in the newly-formed vat, we may with- 
 out fear plunge in the stuff intended to be dyed ; but the tints 
 given during the first working of the vat are never so brilliant 
 as those subsequently formed ; this is owing to the yellow- 
 coloring matters of the pastel, which, aided by the heat, become 
 fixed on the wool at the same time as the indigo, and thus give 
 to it a greenish tint. This accident is common both with the 
 pastel and the woad vats ; it is, however, less marked in the 
 latter. 
 
 " When the stuff or cloth has been immersed for an hour in 
 the vat it should be withdrawn; it would, in fact, be useless to 
 leave it there for a longer time, inasmuch as it could absorb no 
 more of the coloring principle. It is, therefore, to be taken 
 from the bath and hung up to dry, when the indigo, by attract- 
 ing oxygen, will become insoluble and acquire a blue color. 
 Then we may replunge the stuff in the vat, and the shade will 
 immediately assume a deeper tint, owing to renewed absorption 
 of indigo by the wool. By repeating these operations, we suc- 
 ceed in giving very deep shades. We must not, however, 
 imagine that the cloth seizes only on that portion of indigo 
 contained in the liquor required to soak it. Far from such 
 being the case, experience shows that, during its stay in the 
 bath, it appropriates to itself, within certain limits, a gradually 
 increasing quantity of indigo. We have here, then, an action 
 of affinity, or perhaps, a consequence of porosity on the part 
 of the wool itself. 
 
 " Woad Vat. — These vats are extensively employed at Lou- 
 viers, and in the manufactories of the north of France. The 
 bath is prepared in the same manner as in the foregoing case; 
 the finely-cut root is introduced into the copper along with 2 
 
298 
 
 INDIGO. 
 
 lbs. of pounded indigo, 9 lbs. of madder, and 15 J lbs. of slaked 
 lime. The liquor is, after the necessary ebullition, poured 
 upon the woad. This substance contains but a very small 
 quantity of coloring principle ; we must, therefore, add some 
 indigo when preparing the vat, so as to indicate the precise 
 instant when the mixture arrives at the point of fermentation 
 so necessary for imparting hydrogen to the coloring principle, 
 and for rendering it soluble. We must also use a larger quan- 
 tity of lime, since the woad contains no ammonia resulting from 
 previous decomposition, such as we find to be the case with 
 the pastel of the south. When the vat is in a suitable state of 
 fermentation, a rusty color becomes manifest, in addition to 
 the signs already described in speaking of the pastel vat; be- 
 sides the ammoniacal odor, the bath always retains the peculiar 
 smell of the woad. The pounded indigo is now added, and we 
 proceed, in the manner already detailed, to reduce it to a state 
 of solution fit for dyeing. 
 
 " The vats prepared by means of pastel have greater dura- 
 bility than those made with the woad ; but it is thought that 
 the colors given by the latter are more brilliant than those 
 obtained from the former dye. 
 
 " Modified Pastel Vat. — This vat is about 7 feet in depth, 
 and 6| feet in diameter. It is made of copper, and heated by 
 steam. The lid is composed of three segments, each of which 
 is formed of two planks, about an inch thick, and strongly 
 secured together by bolts. 
 
 u The beating is performed in the usual way, with sticks, 
 before the first dipping, after having moistened the cloth in 
 tepid water. This operation is not subsequently repeated. 
 
 "This vat is prepared with 13 lbs. of indigo, 17 J lbs. of 
 madder, 4J lbs. of bran, 9 lbs. of lime, and 4J lbs. of potash. 
 Having filled the vat, we heat it to about 200° Pah., and, as 
 soon as the water is tepid, introduce 441 lbs. of pastel. The 
 liquor becomes of a yellowish-brown color; small bubbles ap- 
 pear upon its surface, ordinarily at the end of four hours if the 
 vat be heated by steam, but not until after eight or twelve 
 hours where heat is applied by the common fire ; in the latter 
 case the mixture should be stirred every three hours. When 
 the liquor displays the signs of fermentation, we add the above- 
 mentioned ingredients, and cover the vat over ; it is then to 
 be set aside, stirring it every three hours, or oftener if the fer- 
 mentative action be very rapid. Each time that it is stirred 
 we are to add from 2 to 4 lbs. of lime; if fermentation proceed 
 quickly we even use more, but in the contrary case less. After 
 about eighteen hours, we plunge into the vat three pieces of 
 common cloth, measuring from twenty to twenty-five ells in 
 
INDIAN VAT. 
 
 299 
 
 length each; when they have received six or seven turns, they 
 are to be taken out again. The object of this is to remove the 
 excess of lime from the bath. The vat is then set aside for 
 three hours, when it is to be stirred, and 13 lbs. of indigo, with 
 2 lbs. of madder, added to it. We now again apply heat to 
 the mixture. 
 
 " If the vat contains a superabundance of lime, it will be un- 
 necessary to add more ; otherwise we throw in a further quan- 
 tity. During the night it should be covered with a cloth, and 
 a workman left to watch it. It is usually stirred once before 
 the morning; but if it be deficient in lime, it will require this 
 manipulation to be more frequently repeated, and also fresh 
 lime added to it. On the following day the stirring should be 
 continued every three hours, and so on for the next thirty 
 hours, taking care to heat the vat from time to time. On the 
 morning of the fourth day the dyeing may be commenced. 
 
 "The temperature should be maintained at a pretty uniform 
 point; if it be too hot, the blue takes a red reflection, by rea- 
 son of the madder contained in the liquid. A vat thus pre- 
 pared will last three months; we may even work it for double 
 that period, but after the third month it appears to lose some 
 of its indigo. 
 
 "We maintain the power of the vat by introducing every 
 night 2J lbs. of madder. Some indigo is also added twice or 
 three times a week. These additions are made in the evening. 
 After the former, the vat is left at rest for forty-two hours ; 
 with the latter only for twenty-four, at the same time observing 
 the precautions already indicated. At the end of three months, 
 or sooner when we wish to stop the working of the vat, we 
 exhaust the indigo ; for this purpose we continue to charge it 
 every night for the space of a month with madder, and dip 
 into it white cloths, or more particularly woollen tissues, which 
 become more or less loaded with the indigo. We must con- 
 tinue this plan until these matters take up no further color. 
 The dippings are to be performed twice a-day at first, but once 
 only towards the termination. Many dyers make use of this 
 bath for preparing a new vat, but it is better to throw this 
 away and make it up afresh with common water. 
 
 "Indian Vat. — These vats are of more simple and of more 
 ready construction than the pastel or woad vats. We are to 
 boil in water a quantity of madder and of bran, proportioned 
 to the weight of indigo which we wish to employ. After two 
 hours' ebullition, we turn into this bath some tartar-lees, which 
 are also to be boiled for an hour and a-half or two hours, so as 
 to charge the bath with whatever soluble matter they may 
 contain ; after this ebullition the bath should be allowed to 
 
300 
 
 INDIGO. 
 
 cool, and the indigo, which has been previously ground, is then 
 to be introduced. Supposing that we wish to employ 21 lbs. 
 of indigo, the following would be the proportions used in pre- 
 paring this vat: 41 lbs. of tartar lees, 13 lbs. of madder, and 
 5 lbs. of bran. These vats are usually mounted in coppers of 
 a conical shape; a small fire should be kept up around them, 
 so as to maintain a moderate and uniform heat. The indigo 
 will usually be found dissolved at the end of twenty-four hours, 
 often even after twelve or fifteen hours. The liquor has a 
 reddish color in the new vats, and a green tint in those which 
 are in a working state. The frothy surface, as well as the 
 brilliant-colored pellicle, becomes manifested in this as in all 
 other preparations of a like kind. 
 
 "This species of vat has to be renewed much more frequently 
 than the woad and pastel vats, from the indigo being more diffi- 
 cult to dissolve after a certain lapse of time. A moderate heat 
 should be maintained in all these vats. 
 
 "Potash Vat. — This species of vat is extensively employed 
 at Elbeuf for the dyeing of wool in the flock. It presents in 
 all respects a perfect analogy with the Indian vat ; in fact, the 
 action of the tartar-lee in the latter preparation depends entirely 
 on the carbonate of potash which it contains. The ingredients 
 used in the preparation of the potash vat are — bran, madder, 
 and the subcarbonate of potash of commerce. 
 
 "We obtain the deep shades in this species of vat with 
 greater celerity than in all others, a fact which undoubtedly 
 depends on the greater power which potash has of dissolving 
 indigo than is possessed by lime. Experience proves that the 
 potash vat has the advantage in point of celerity of nearly a 
 third ; but this is balanced by the inconvenience resulting from 
 the darker shade, which we must attribute to the large quantity 
 of coloring matter of the madder dissolved by the alkaline lee, 
 and which becomes fixed on the stuff with the indigo. 
 
 "To render this vat in its most favorable state, the indigo 
 should be made to undergo a commencement of hydrogenation 
 before turning it into the mixture ; for this purpose we prepare 
 in a small copper a bath analogous to that in the vat, to which 
 the pounded indigo is added. This bath is maintained for 
 twenty-four hours at a moderate heat, taking care to stir it 
 from time to time. The indigo assumes a yellowish color, be- 
 comes dissolved, and in this state is turned into the vat ; we 
 thus avoid many delays and losses in its preparation, and, in- 
 deed, it would be desirable if a similar plan were adopted with 
 all these compounds. 
 
 "German Vat. — This vat is of nearly similar dimensions to 
 that used for the woad, being three times the size of the potash 
 
GERMAN VAT. 
 
 301 
 
 vat. Its diameter is about 6| feet, and its depth 8 J feet. 
 Having filled the copper with water, we are to heat it to 200° 
 Fah.; we then add 20 pailsful of bran, 22 lbs. of carbonate of 
 soda, 11 lbs. of indigo, and 5J pounds of lime, thoroughly 
 slaked, in powder. The mixture is to be well stirred, and then 
 set aside for two hours; the workman should continually watch 
 the progress of the fermentation, moderating it more or less 
 by means of lime or carbonate of soda, so as to render the vat 
 in a working state at the end of twelve, fifteen, or, at the most, 
 eighteen hours. The odor is the only criterion by which the 
 workman is enabled to judge of the good state of the vat, he 
 must therefore possess considerable tact and experience. 
 
 " In the process of dipping we introduce 84 lbs., 106 lbs., 
 or even 130 lbs. of wool, in a net bag, similar to that used in 
 the woad vat, taking care that the bag is not allowed to rest 
 against the sides of the copper. When the wool has sufficiently 
 imbibed the color, we remove the bag containing it, and allow 
 it to drain for a short time over the vessel. We operate in this 
 way on two or three quantities in succession ; we then remove 
 the vat, and set it aside for two hours ; we must be careful, 
 from time to time, to replace the indigo absorbed by the wool, 
 as also to add fresh quantities of bran, lime, and crystallized 
 carbonate of soda, so as constantly to maintain the fermentation 
 at a suitable point. 
 
 " The German vat differs, then, from the potash vat by the 
 fact that the potash is replaced by crystallized carbonate of 
 soda and caustic lime, which latter substance also gives to the 
 carbonate of soda a caustic character. It presents a remark- 
 able saving as compared to the potash vat ; hence the frequency 
 of its employment ; but it requires great care, and is more 
 difficult to manage. It also offers considerable economy of 
 labor; one man is amply sufficient for each vat. 
 
 u The army cloth is usually dyed by means of the pastel vat, 
 which gives the most advantageous results. We here make 
 use of vats about 8 J feet in depth, and 5 feet in diameter, into 
 which we introduce from 361 lbs. to 405 lbs. of pastel or of 
 woad, after previous maceration. The vat is to be filled with 
 boiling water, and we then add to the bath 22 lbs. of madder, 
 17^ lbs. of weld, and 13 lbs. of bran. The mixture is to be main- 
 tained in a state of ebullition for about half an hour; we next 
 add a few pailsful of cold water, taking care, however, not to 
 lower the temperature beyond 130° Fah.; during the whole of 
 this time a workman, provided with a rake, keeps incessantly 
 stirring the materials of the bath. The vat is then accurately 
 closed by means of a wooden lid, and surrounded by blankets, 
 so as to keep up the heat. It is now put aside for six hours ; 
 
302 
 
 INDIGO. 
 
 after this time it is again stirred by means of a rake, for the 
 space of half an hour ; and this operation should be repeated 
 every three hours until the surface of the bath becomes marked 
 with blue veins; we then add from six to eight pounds of 
 slaked lime. 
 
 " The color of the vat now borders on a blackish-blue. We 
 immediately add the indigo in a quantity proportioned to 
 the shade which we wish to obtain. The pastel in the fore- 
 going mixture may last for several months ; but we must renew 
 the indigo in proportion as it becomes exhausted, at the same 
 time adding both bran and madder. In general we employ — 
 
 " 11 to 13 lbs. of good indigo for 100 lbs. of fine wool. 
 
 "9 to 11 lbs. of good indigo for 100 lbs. of common wool. 
 
 u 9 to 11 lbs. of good indigo for 131 yards of cloth dyed in 
 the piece. 
 
 "Management of the Vats. — A good condition of the vat 
 is recognized by the following characters : The tint of the bath 
 is of a fine golden-yellow, and its surface is covered with a 
 bluish froth and a copper colored pellicle. On dipping the rake 
 into the bath, there escape bubbles of air, which should burst 
 very slowly; when they vanish quickly, it becomes an indica- 
 tion that we must add more lime. The paste which is found 
 at the bottom of the vat, green at the moment of its being 
 drawn up, should become brown in the air ; if, however, it re- 
 mains green, this is a further sign that more lime is required. 
 Lastly, the vat should exhale the odor of indigo. We usually 
 complete the assurance of the vat being in a good state by 
 plunging into it, after two hours' respite, a skein of wool, which, 
 on being withdrawn after the lapse of half an hour, should 
 present a green color, but change directly to blue. We then 
 once more mix the materials of the vat, and two hours after, it 
 may be considered ready for dyeing. 
 
 "These vats, like those already described, are provided with 
 a large wooden ring, the interior of which is armed with a kind 
 of network, for the purpose of preventing the objects which are 
 intended to be dyed coming in contact with the materials at the 
 bottom of the vat; we, moreover, take the precaution of in- 
 closing the wool or cloth in bags. These tissues, when plunged 
 into the bath, should remain there for a longer or shorter time, 
 according to the shade which we wish to obtain; one dipping, 
 however, will never suffice for this object; usually we leave in 
 the stuff for half an hour only ; it is then to be taken from the 
 bath, wrung, and exposed to the air. This operation is repeated 
 until we have succeeded in procuring the desired shade ; we 
 ordinarily suffer three hours to elapse between each dipping. 
 The heat ot the vat should never be allowed to fall below 130° 
 
MANAGEMENT OF THE VATS. 
 
 303 
 
 Fah. After each operation the bath must be well stirred, and 
 fresh lime added ; generally speaking, a pound a day will 
 suffice. We re-establish the indigo about every second day. 
 When once this vat is well mounted, and we are careful to 
 examine its working, we may dye from two to four batches a 
 day with it. 
 
 " When the stuffs have acquired the desired shade, they are 
 first to be washed in common water, and then in a very weak 
 solution of hydrochloric acid (about one part in a thousand) ; 
 after this they are again rinsed in pure water. 
 
 u The Indian vat is much more easily managed than the fore- 
 going; it presents less danger of failure, from the fact that it is 
 quickly exhausted, and also from the fermentative process, which 
 is so difficult to govern in the pastel vat ; this vat not having 
 time to change in character. It is prepared by first introducing 
 an equal quantity of madder and of bran, and a triple quantity 
 of potash ; this is to be gradually heated until it reaches a 
 temperature of 167° Fah., and we then add to it the indigo, 
 thoroughly agitating the matters for half an hour. The vat is 
 maintained at a temperature of 86° to 100° Fah., by keeping 
 it closely covered, and at the same time the mixture is to be 
 stirred occasionally at intervals of twelve hours. It should by 
 this time present a beautiful green shade, the liquor being sur- 
 mounted by a copper-colored pellicle and a purplish froth. We 
 may now commence the dyeing, following the same course 
 as with the pastel vat; but the stirrings being here repeated 
 much more frequently than with the other mixture, we can dye 
 a larger quantity of wool within a given time. When the vat 
 ceases to give a brilliant blue, we must altogether renew it; if 
 it be merely weakened, we add to it a small quantity of freshly- 
 prepared liquor containing a few pounds of potash, and a little 
 less bran and madder. In giving the dark and the clear sky- 
 blues, we must be careful to employ a quantity of indigo pro- 
 portioned to the color which we wish to obtain, or, better still, 
 we may use the previously exhausted vat for the dark blue. 
 
 "When exposed to the influence of the putrid fermentation, 
 indigo is decomposed and loses its color. If rendered soluble, 
 it obeys the impulse communicated to theazotized matters with 
 which it is brought into contact, although, if macerated in pure 
 water at the ordinary temperature, it is itself decomposed with 
 great difficulty. 
 
 " The pastel and the woad are very prone to the putrid fer- 
 mentation, by reason of the large quantity of azotized matters 
 which they contain, as do all the cruciferae ; they require, 
 therefore, considerable care in their employment. 
 
 " When a vat is mounted, if the fermentation be allowed to 
 
304 
 
 INDIGO. 
 
 continue unchecked, after the appearance of the blue froth and 
 the other signs already indicated, the liquor will acquire a yel- 
 low color similar to that of beer; the froth will become white; 
 it will give out a stale smell and lose its ammoniacal odor ; after 
 a few days it will turn whitish, and exhale a smell at first simi- 
 lar to that of putrefied animal substances; then it will acquire 
 the odor of rotten eggs, and set free sulphureted hydrogen. 
 The lime in the pastel and the woad vats, and the tartar-lee 
 and potash in the other mixtures, are used for the purpose of 
 preventing these accidents. 
 
 " Besides the oxygenated compound, which is formed by 
 the combinaiion of oxygen with the extractive matters of the 
 plants held in digestion, there is a production of carbonic acid 
 which saturates the alkaline lee, and forms a carbonate of lime 
 in the pastel vat. We find this attached to the sides of the 
 vat in such quantity, that the inside of these vessels becomes 
 incrusted with it to a considerable depth. It is this product 
 which dyers call the tartar of the vat; it effervesces with acids, 
 and gives on analysis carbonic acid, lime, and a few particles 
 of indigo. In the potash vat the solubility of the carbonate 
 of potash prevents its deposition; but it is very probable that 
 we have even here a formation of some carbonated products, 
 perhaps in part formed at the expense of the carbonic acid of 
 the air. 
 
 "The soluble extractive principle being the only matter 
 which remains in solution in the bath with the indigo, the 
 lime, &c., we have formed deposits which, varying both in their 
 volume and in the greater or less facility with which they are 
 precipitated during the various periods of fermentation, lead to 
 a more or less considerable waste of time. If we plunge a 
 piece of woollen tissue into a vat which has been recently 
 stirred, it will acquire a dark color, and will be found covered 
 with brown stains which are with difficulty removed. When 
 the woad or paste vat has been stirred, it need be left two or 
 three hours only before plunging in the stuff, at least during 
 the early months of its working, inasmuch as the pastel, being 
 but slightly divided and attenuated, is readily precipitated; but 
 when, by reason of its extreme division, in consequence of 
 repeated operations, it is thrown down with less facility, the 
 dipping should not be performed oftener than three times in the 
 day. 
 
 "The Indian vat requires less time than the others; we may 
 even dye with it an hour after stirring the mixture. The 
 potash, being soluble, forms no precipitate; while the ligneous 
 fibre of the madder and the pellicles of the bran become de- 
 
INDIGO. 
 
 305 
 
 posited with great facility. We can also dip with these vats 
 much oftener than with those made by pastel or woad." 
 
 We here give three compositions for the copperas vat: — 
 
 Dark Blue. Medium. Light Blue. 
 
 Water (buckets), 600 600 600 
 
 Caustic lime (lbs.), 88 83 13.5 
 
 Copperas (lbs.), 77 22 5.0 
 
 Ground indigo (lbs.) 33 11 2.2 
 
 Soda ash (lbs.), 2.2 
 
 Receipts and formulas require in their application not only 
 that the figures should be followed, but also that the quality of 
 the ingredients should not vary too much. The want of suc- 
 cess in many indigo vats is often caused by employing poor 
 materials, too far from a good average. Indigo is a substance 
 which contains from 35 to 75 per cent, of true indigo. With 
 such a wide range, analyzing indigo by sight only, may lead to 
 incorrect results, and great trouble in the management of the 
 vats. 
 
 If the indigo is too poor, and the regular proportion of lime 
 and copperas is added, the protoxide of iron will swim if it 
 does not precipitate part of the indigo, which is probable, when 
 we consider that the deposit of the vats often contains a com- 
 pound of iron and indigo. Lime is to be considered also; 
 American limes are always mixed with more or less magnesia. 
 The sulphate of lime formed goes to the bottom, but the sul- 
 phate of magnesia is very soluble; and by successive additions 
 of magnesia and lime, the specific gravity of the liquid may be 
 increased to a point when the insoluble substances will have 
 difficulty to reach the bottom, and hence they will swim. It 
 would be better to employ limes free from magnesia. White 
 marble lime, and especially oyster lime, do not contain mag- 
 nesia. 
 
 Copperas suspected of having in it too much peroxide can be 
 transformed into sulphate of protoxide by boiling it in a vessel 
 lined with lead, with clean iron scraps or turnings. A small 
 addition of oil of vitriol, if the copperas is not already very 
 acid, will help the transformation. After boiling, if the solu- 
 tion is not immediately used, it should be covered with boards. 
 
 Carmine of indigo has been recently manufactured with a 
 refined indigo, treated by strong muriatic acid, which dissolves 
 the lime, iron, and amylaceous substances ; and subsequently by 
 a weak solution of caustic soda, which dissolves other organic 
 impurities. The result is a great brilliancy of shades. 
 20 
 
306 
 
 LOGWOOD. 
 
 Logwood. 
 
 Logwood is the Boisde Campeche and Boisbleu of the French, 
 and the Blavhoh of the German dyers. This wood is brought 
 to us from Jamaica and from the eastern shores of the Bay of 
 Campeachy; on this account it is distinguished in commerce 
 by the names of Campeachy and Jamaica logwood. The former 
 is considered much superior to the latter, and brings always a 
 higher price in the market. Among botanists, the logwood 
 tree is known by the name of Hcematoxylon Campechiacum. In 
 a favorable soil it grows to a very great size ; its bark is thin 
 and smooth, but furnished with thorns ; its leaves resemble 
 the laurel; the wood is hard, compact, and capable of taking 
 a fine polish ; its specific gravity is much higher than water, in 
 which it consequently sinks. 
 
 We are not aware who first introduced logwood as a dyeing 
 agent; but its nature, and the art of using it as such, seem to 
 have been but little understood in the reign of Queen Eliza- 
 beth; for we find her government issuing an enactment entirely 
 forbidding its use. The document is curious, and affords a 
 good proof of the absurdity of a government interfering with 
 the industry of its subjects. The act is entitled "An Act for 
 the abolishing of certeine deceitful stuffe used in dyeing of 
 clothes and it goes on to state that, "Whereas there hath 
 been brought from beyond the seas a certeine kind of stuffe 
 called logwood, alias blockwood, wherewith divers dyers," &c, 
 and "Whereas the clothes therewith dyed, are not only solde 
 and uttered to the great deceyte of the Queene's loving sub- 
 jects, but beyond the seas, to the great discredit and sclaunder 
 of the dyers of this realme. For reformation whereof, be it 
 enacted by the Queene our Soveraygne Ladie, that all such log- 
 wood, in whoes handes soever founde, shall be openly burned 
 by authoritie of the maior."* This act was put forth in the 
 23d year of the Queen's reign, and was renewed again in the 
 39th, with the addition that the person so offending was liable 
 to imprisonment and the pillory. Upwards of eighty years 
 elapsed before the real virtues of this dyeing agent were ac- 
 knowledged ; and there is no dyewood we know now so uni- 
 versally used, and so universally useful. 
 
 Like many other valuable substances, logwood was long used 
 before anything was known of the real nature of the coloring 
 principle. Chevreul made a chemical examination of the wood, 
 and found it to contain a distinct coloring substance, which he 
 called hasmatine, a name which has since been changed to haema- 
 
 * Parkes, Chemical Essays, 8vo. vol. i. page 632. 
 
COLORING MATTERS. 
 
 307 
 
 toxylin,to avoid any confusion with a substance having a simi- 
 lar name, contained in blood. Logwood contains, besides this 
 coloring matter, resin and oil, acetic acid, and a double salt of 
 potash and lime, with a vegetable acid. It sometimes contains 
 also sulphate of lime, a little alumina, peroxide of iron, and 
 oxide of manganese. These ingredients, however, vary; some 
 woods having more than others, and others wanting some of 
 them altogether. These varieties of constitution probably 
 arise from the varying qualities of the soil on which the wood 
 is grown. 
 
 We have frequently tried pieces of logwood as imported, and 
 the average ash left after burning was 1.5 per cent., half of 
 which was lime, with a trace of iron, and the remainder con- 
 sisted of magnesia, alumina, and silica. 
 
 Chevreul's process for procuring the coloring matter is by 
 subjecting logwood, after grinding, to digestion for a few hours 
 in water at 120° or 130° Fah., afterwards filtering the liquor 
 and evaporating to dryness ; what remains is put into strong 
 alcohol for a day; this is again filtered, and the clear liquor 
 evaporated till it becomes thick ; to this is added a little water, 
 and evaporated anew ; it is then left to itself, and the coloring 
 matter crystallizes. 
 
 An improvement on this method has been recommended by 
 Erdmann. The extract of logwood being evaporated to dry- 
 ness, is pulverized, and mixed with a considerable quantity of 
 pure silicious sand, to prevent the agglutination of the extract, 
 and the whole allowed to stand several days with five or six 
 times its volume of ether ;. the mixture being often shaken, the 
 clear solution is poured off and distilled, until there is only a 
 small syrupy residue. By this means most of the ether is saved ; 
 and this residue being mixed with a certain quantity of water, 
 is allowed to stand for some days, when the hematoxylin crys- 
 tallizes out, and may be dried between folds of blotting paper. 
 
 We are afraid both of these processes will be too tedious for 
 adoption in a dye-house. We have seen some very good speci- 
 mens of the hsematoxylin obtained by evaporating a strong 
 decoction of logwood nearly to dryness, and allowing it to 
 stand for several days; a solid matter settles to the bottom, 
 having a syrupy fluid above it; large crystals of hematoxylin 
 appear to grow from the crust, giving it, when removed, a 
 most beautiful velvety appearance. The crystals vary in length 
 from one-fourth to five-eighths of an inch. They dissolve rea- 
 dily in hot water, but very slowly in cold ; they are also soluble 
 in alcohol. When dissolved in distilled water, the solution has 
 a beautiful rich wine color ; but when the least trace of lime or 
 
308 
 
 LOGWOOD. 
 
 iron is present in the water (and very few waters are free from 
 these), its color is materially altered. The action of reagents 
 is very powerful. Potash, when first put in, colors the solution 
 violet ; but this speedily passes into a purple, becoming brown- 
 ish-yellow; and, in a little time, the mixture becomes almost 
 colorless. The reason of this final change is, that a quantity of 
 oxygen is absorbed; the hematoxylin is thereby destroyed, 
 and the caustic alkali converted into a carbonate from the de- 
 composition of the coloring matter. Caustic soda has a similar 
 effect; but the carbonate of soda is much more mild in its 
 action than carbonate of potash. 
 
 An extract of logwood is sold in France in a crystalline form, 
 and is obtained from a decoction of the wood. The crystals 
 are dark-red, nearly black; it is hematoxylin, with several im- 
 purities, but yields a very considerable quantity of color. 
 
 The action of ammonia on hematoxylin is similar to that of 
 potash and soda, but much more powerful in regard to its 
 changing color, and less destructive upon the substance. Some 
 beautiful and also amusing experiments may be performed 
 with ammonia and the coloring matter of logwood. If a jar 
 full of distilled water be taken, and a few drops of a solution 
 of hematoxylin be added, not so much as to give a perceptible 
 coloring to the water; on adding a few drops of ammonia, the 
 water instantly takes a reddish tint, and changes so rapidly, 
 that in two minutes, if the jar is large, the color is so dark a 
 violet shade that the light can hardly be transmitted ; in a 
 little it becomes redder, and gradually passes away. This ex- 
 periment may be repeated by placing the jar simply in the 
 fumes of ammonia ; the water begins to color at the top, and, 
 as the absorption goes on, the color passes gradually down, so 
 that when it is dark at the top, it is slightly tinged at the bot- 
 tom, and so on till the whole is converted into a dark violet, 
 seemingly by magic. 
 
 Erdmann has been able to collect this compound of hema- 
 toxylin and ammonia, and finds that the coloring matter ab- 
 sorbs three equivalents of oxygen under the influence of the 
 ammonia, and is converted into a substance which he names 
 hwmatein. This hematein combines with ammonia, and forms a 
 violet-black powder, which is soluble in water, giving it an 
 intense purple color, which spontaneously fades, and passes 
 away by keeping. 
 
 The action of alkalies upon logwood is similar to those de- 
 scribed upon its coloring matter, and suggests the cause why 
 those who add a little alkali to their logwood liquor while dye- 
 ing black, on purpose to give the color of the logwood a rich- 
 ness, and prevent the action of the iron upon it, invariably 
 
COLORING MATTERS. 
 
 309 
 
 have a bad grayish-black. Stale urine, indeed, which is most 
 generally used for this purpose, if not used cautiously, pro- 
 duces the same bad color from the ammonia which it contains. 
 For this reason, also, we always wash off the lime, when it is 
 used to pass the cloth through it after being impregnated with 
 iron, otherwise the lime on the cloth causes the coloring mat- 
 ter to undergo similar changes with the other alkaline sub- 
 stances, and gives the blacks thus dyed a grayish appearance. 
 Indeed, so delicate is the action of all earthy and alkaline salts 
 upon logwood, that it has been proposed as a test for the pre- 
 sence of lime in water. 
 
 In the chemical investigation of logwood, the coloring mat- 
 ter has been obtained in two conditions, differing in chemical 
 composition only in one having more water than the other; 
 but these researches have led to some curious and interesting 
 speculations upon the relation which it has to other blue color- 
 ing matters of vegetables, particularly those of indigo and 
 orceine (the coloring matter of archil). There is, however, 
 this difference, that hematoxylin has no nitrogen, the others 
 have; but instead of nitrogen it has water. Their compara- 
 tive compositions are as follows: — 
 
 Orceine 
 Indigo blue . 
 Indigo white 
 
 Protohydrate hematoxylin 
 Perhydrate heematoxylin 
 
 These analogies, in connection with the relations of color, 
 are striking; and if we could, by some transformation, obtain 
 in the other two matters the permanence of indigo, the acqui- 
 sition would be highly worthy of attention. 
 
 The action of metallic oxides upon the coloring matter of 
 logwood is somewhat similar to the action of these oxides on 
 logwood itself, varying considerably with the dissolving men- 
 strua of the oxide, and the particular state of oxidization. 
 
 Pjotosalts of iron give Blue-black precipitates, permanent. 
 Persalts of iron Jet-black precipitates, which be- 
 come brown. 
 
 Protosalts of tin Kich wine-color precipitates, per- 
 manent. 
 
 Persalts of tin Deep wine-color precipitates, which 
 
 • become brown. 
 
 Acetate of lead Brownish-black precipitate, which 
 
 passes to gray. 
 
 Acetate of copper . . . Greenish-black, passing to brown. 
 Salts of alumina .... Wine-color precipitates, permanent. 
 
 c. 
 
 H. 
 
 0. 
 
 N. 
 
 Water, 
 
 32 
 
 18 
 
 7 
 
 2 
 
 
 32 
 
 10 
 
 4 
 
 2 
 
 
 32 
 
 10 
 
 2 
 
 2 
 
 2 
 
 32 
 
 14 
 
 i 6 
 
 0 
 
 1 
 
 32 
 
 14 
 
 6 
 
 0 
 
 3 
 
310 
 
 LOGWOOD. 
 
 These are the principal metallic salts used with logwood, 
 and their effects. The acid in which the oxides are dissolved 
 affects materially the results obtained; the iron is used in the 
 state of sulphate or acetate; the tin as chloride, with free acid ; 
 lead and copper as acetates. The protosalts give, with log- 
 wood, the most brilliant, and also the most permanent colors; 
 this should be constantly attended to. The iron protosalts, if 
 exposed to the air, pass very readily into the state of persalts, 
 especially if the salts be neutral — that is, have no more acid 
 than is combined with the oxide. A little free acid prevents 
 this change, but generally produces bad effects upon logwood. 
 However, where the use of a protosalt of iron is necessary, any 
 persalt in the mordant may be reduced to the proto-state by 
 the immersion in it of a piece of clean iron, a few hours pre- 
 vious to using the solution. When an iron salt becomes peroxi- 
 dized by exposure to the air, every third atom is precipitated 
 as an insoluble oxide — the acid leaving this atom, and com- 
 bining with two atoms iron, and three oxygen, to form a per- 
 salt (page 154). When a piece of iron is put into a persalt 
 solution, the following reaction takes place: — 
 
 Persalt of iron composed 
 
 Iron .Protosalt, 
 
 Iron .... -^^^p r otosalt. 
 
 Oxygen- 
 Oxygen- 
 Oxygen s 
 Acid.. 
 Acid.. 
 Acid.. 
 
 Piece of clean iron ^ Protosalt. 
 
 This operation ought to be performed just previous to using 
 the solution, which should be as little exposed as possible; for 
 when the salt is all converted into the proto-state ; the atmo- 
 sphere again speedily destroys it. 
 
 Decoctions of logwood are prepared in the dye-house either 
 by boiling or by scalding ; if the logwood is chipped or cut, 
 it requires to be boiled for two or three hours. This generally 
 gives the purest and finest colors for plumb tabs. When the 
 wood is ground, the decoctions are generally made by pouring 
 boiling water upon it. Some dyers put the quantity required 
 into a tub; fill this with boiling water; allow the grounds to 
 settle, and decant the solution; but the best method is to use 
 a basket, lined with cloth; the logwood is put into the basket, 
 and boiling water is poured upon it ; the clean decoction filters 
 through. No more logwood should be taken than what is to 
 be used at the time, as it loses its dyeing properties by stand- 
 
PREPARATION OF DECOCTIONS. 
 
 311 
 
 ing; the color passes from a rich wine hue to a yellow-brown, 
 and assumes a syrupy appearance ; and colors dyed by it after 
 this change takes place are always wanting in brilliancy; be- 
 sides, it takes a greater quantity of stuff* to produce the same 
 depth of shade. This may be caused by a partial decomposition 
 of the coloring matter, or of the other ingredients of the wood 
 reacting upon the coloring matter. 
 
 Parkes, in his Chemical' Essays, has the following observa- 
 tions bearing upon this subject: ''Considerable advantage is 
 derived by the woollen dyers from the use of water in the 
 preparation of rasped logwood. As the wood is cut into chips, 
 they sprinkle it abundantly with water, and in that moistened 
 state it is thrown into large heaps, and sometimes into bins of 
 great size, where it is suffered to lie as long as is convenient. 
 By this treatment the chips become heated, or they ferment, as 
 the dyers call it, and thus undergo a very remarkable change ; 
 for, after having lain a few months in this state, they give out 
 the coloring matter in the dyeing copper much more easily ; 
 and any given quantity of such chips will produce a more in- 
 tense dye than could have been obtained from an equal quan- 
 tity of chips which had not been thus heated. It is difficult to 
 account for this, unless we suppose that the water becomes in 
 part decomposed, and that its oxygen, uniting with the vege- 
 table coloring matter, renders it more intense." We have found 
 that, by damping the wood with boiling water a little before' 
 pouring the necessary quantity of boiling water upon it, the 
 wood, in the language of the dyer, is much better bled ; but we 
 consider this to result from softening the particles of wood, and 
 so making the coloring matter more easily dissolved by the 
 water afterwards applied. Whether anything more is effected 
 by the practice noticed by Mr. Parkes, or if any decomposition 
 takes place, we cannot say. If by fermentation is meant the 
 formation of acids, we know that acids do not produce the effects 
 stated ; but if it is a fermentation caused by the decomposition 
 of any substance having nitrogen as a constituent, the result 
 would be the formation of ammonia, a substance, as we have 
 already noticed, which has a powerful influence upon the color- 
 ing matter of logwood, and extracts it very rapidly — a property 
 possessed, indeed, by all alkalies and alkaline earths. This is 
 well known to dealers in logwood, who occasionally sprinkle it 
 with water containing a little lime, which gives the wood a 
 richness in color, so that the poorest woods, thus doctored, appear 
 equal to those of the finest quality. Such wood, however, 
 never produces good light shades. The presence of an alkali 
 may be detected in logwood, by taking a little in a tumbler, 
 and allowing it to steep for a few hours in distilled water, and 
 hen trying the solution with delicate test-papers. 
 
312 
 
 LOGWOOD. 
 
 This practice of putting lime-water upon the ground logwood 
 may be one reason why decoctions of ground logwood lose 
 their coloring power so rapidly by standing ; as all alkaline 
 matters in connection with logwood, although they give, in 
 the first place, a richness of color, soon pass into a brown, and 
 the color decays. 
 
 There is yet no simple and accurate process for testing log- 
 wood which could be introduced into the dye-house, although 
 there are few substances of apparently greater variety. The 
 differences, however, often consist only in the moisture and in 
 the doctoring. 
 
 The method generally adopted for judging of the value of 
 logwood consists in comparing the color of samples of yarn 
 dyed by different specimens of it. A given weight of each of 
 the logwood samples is macerated in boiling water and then an 
 equal quantity of mordanted cotton is dyed by each of the 
 several decoctions; the depth and kind of color produced are 
 the test of the quality. With care this method is very satis- 
 factory for practical purposes; but an oversight is often made 
 in these trials in not taking the quantity of water which is in 
 the sample. It is necessary that ground logwood should be a 
 little damp, to prevent it flying away as dust, but it is also 
 requisite to avoid paying for the water put into it at the same 
 rate as for logwood ; care ought therefore to be taken not only 
 to dry the»samples, but also to ascertain the water contained in 
 them. This will be rendered more apparent by stating the 
 results of some experiments directed to this point. Samples 
 of w r ood, as imported, before being ground or chipped, kept at 
 a temperature of 212°, as long as it decreased in weight, gave 
 a loss ranging from 9 to 16 per cent.; average 12 per cent. 
 The moisture in ground logwood, as supplied to the dver, 
 ranges from 88 to 46 per cent. ; average 42 per cent. ; so that 
 the amount of water added averages 30 per cent. 
 
 The moisture may be tried by putting a weighed sample of 
 the ground wood upon a piece of paper, or on a plate for some 
 hours in the drying-stove, when no wet goods are in it. In 
 the experiments, of which the results are given above, we used 
 a water-bath, which is preferable. Samples to be tried ought 
 all to be previously submitted to the drying process. 
 
 Water is not the only thing added to logwood; a little lime 
 is occasionally added to the water, which gives the logwood a 
 bloom, and makes it appear better than it really is. In burn- 
 ing samples of ground logwood, and deducting the water that 
 had been added, we have found the ash to vary from 2 to 2.3 
 per cent. 
 
 Were the usual mode of testing, by trying the depth of color 
 
THE PLUMB TUB. 
 
 313 
 
 to be applied with a doctored sample, and one not doctored, say 
 half an ounce of each, the ground wood in each case put into 
 a small basin, and filled with boiling water, and the decoction 
 used to dye a skein of cotton, the doctored sample will be found 
 to yield its color immediately to boiling water, and the other 
 slower — in which case the former, having yielded all its color 
 at once, may give a deeper dye than the other, and yet actually 
 contain less coloring matter. The proper way of proceeding 
 is to take 100 grains of each sample, put the whole quantity 
 upon a filter, and pour boiling water upon it as long as the 
 water passing through is colored, then use all the liquor with 
 cotton so mordanted as to take up all the color. The remain- 
 ing logwood thus exhausted should be nearly colorless; and by 
 drying and weighing it, an approximation to the quantity of 
 color may be obtained. Good logwood loses about 12.5 per 
 cent, in this way after deducting all water. 
 
 We have already referred to the plumb tub and plumb 
 spirits, and stated that if a salt of tin be put into a hot solu- 
 tion of logwood, there is a precipitate formed. If the neutral 
 salt of tin be added to logwood, cold, there is a precipitate 
 formed of a beautiful wine color; but this precipitate is solu- 
 ble in dilute muriatic acid — hence the reason why so much 
 acid is used for the tin in the preparation of the plumb spirits. 
 
 The plumb tub is prepared as follows: A decoction of log- 
 wood is made by boiling, continuing the ebullition until the 
 specific gravity is 8° of Twaddell. This decoction is allowed, 
 to stand till it is perfectly cold; a quantity of tarry matter pre- 
 cipitates in the cooling, so that the clear liquor requires to be 
 decanted. There is then added to it a quantity of plumb 
 spirits, sufficient to raise the specific gravity to about 14° of 
 Twaddell. After standing twenty-four hours, it; is fit for use 
 — which consists simply in immersing the goods for a short 
 time, then taking them out and washing them. As this com- 
 pound of tin and logwood is held in solution by the free acid 
 of the spirits, whenever the cotton impregnated with it is put 
 into water, the dye is rendered insoluble; the repeated wash- 
 ing is necessary to carry oft* all free acid. Occasionally in pre- 
 paring the plumb tub, it happens from some cause, as want of 
 care in making the spirits or the decoction, that the logwood 
 gets all precipitated. This precipitate may all, or the greater 
 part of it, be dissolved by adding hydrochloric acid; but then 
 the tint of color produced upon the goods will not be so blue; 
 it will be more red, with a tendency to brown. Hydrochloric 
 or nitric acid added to a cold solution of logwood, will make a 
 plumb tub without tin; but there being no base, and the solu- 
 tion being soluble in water, it does not form a good dye, being 
 
3U 
 
 BRAZIL-WOODS. 
 
 nearly all removed by washing. But if the goods be previously 
 prepared with a base, colors of various tints may be obtained 
 by this means — which may be resorted to when a plumb tub is 
 not at hand. 
 
 Brazil-Woods. 
 
 The Bois de Pernambouc of the French, and the Brazilien- 
 holz of the German dyers. There are several varieties of this 
 wood, which are distinguished from each other by the name of 
 the locality where they are obtained, such as Pernambuco, 
 Japan, &c. In the dye-house they are often all named peach- 
 wood, from an inferior sort often used, and obtained from 
 Campeachy. 
 
 The Brazil-wood tree, called by botanists Csesalpinia crista, 
 is an American production, and, according to some authorities, 
 gave the name to the country in which it grows,* Brazil, The 
 Portuguese government discovered the value of the wood, and 
 made it an object of royal monopoly; hence it came by the now 
 nearly forgotten name of Queen-wood. It grows mostly in dry 
 places and amongst rocks; its trunk is large, crooked, and full 
 of knots. 
 
 The following paragraph upon these woods is taken from 
 Bell's Geography: u The ibiripitanga, or Brazil wood, called in 
 Pernambuco the pao da rainha (Queen's- wood), on account of 
 its being a government monopoly, is now rarely to be seen 
 within many leagues of the coast, owing to the improvident 
 manner in which it has been cut down by the government 
 agents, without any regard being paid to the size of the tree 
 or its cultivation. It is not a lofty tree. At a short distance 
 from the ground, innumerable branches spring forth and ex- 
 tend in every direction in a straggling, irregular, and unpleas- 
 ing manner. The leaves are small and not luxuriant; the 
 wood is very hard and heavy, takes a high polish, and sinks in 
 water; the only valuable portion of it is the heart, as the out- 
 ward coat of wood has not any peculiarity. The name of this 
 wood is derived from brasas, a glowing fire or coal — its botani- 
 cal name is Gsesalpinia brasileta. The leaves are pinnated; the 
 flowers white and papilionaceous, growing in a pyramidal 
 spike; one species has flowers variegated with red. The 
 branches are slender, and full of many prickles. There are 
 nine species." 
 
 The species brasileto is inferior to the crista; it grows in 
 great abundance in the West Indies. The demand for this 
 
 Southey's History of Brazil, vol. i. 
 
BREZILIN. 
 
 315 
 
 wood a few years ago was so great, owing to its being a little 
 cheaper than the other, that nearly the whole of the trees in 
 the British possessions were cut down and sent home — which 
 Mr. Bell very justly terms improvidence. It is not now so 
 much used, and is consequently scarcer in the market. 
 
 The wood known in commerce as Pernarnbuco is most es- 
 teemed, and has the greatest quantity of coloring matter. It is 
 hard, has a yellow color when newly cut, but turns red by ex- 
 posure to the air. That kind termed Lima-wood is the same in 
 quality. Sapan-wood grows in Japan, and in quality is next 
 to the two named above. It is not plentiful, but is much valued 
 in the dye-house for reds of a certain tint; it gives a very 
 clear and superior color. The quantity of ash that these two 
 qualities of wood contain is worthy of remark. Lima-wood, 
 as imported, gives the average of 2.7 per cent., while Sapan- 
 wood gives only 1.5 per cent.; in both the prevailing earth is 
 lime. The quantity of moisture in the wood averages about 
 10 per cent. That in the ground wood in the market about 20 
 per cent. 
 
 Peach-wood, or Nicaragua, and sometimes termed Santa 
 Martha-wood, is inferior to the other two named, but is much 
 used in the dye-house, and for many shades of red is preferred, 
 although the coloring matter is not. so great. It gives a bright 
 dye. The means of testing the quality of these goods by the 
 dyer is similar to that described for logwood, with the same 
 recommendations and precautions. 
 
 The world is much indebted to the French chemists for their 
 valuable researches into the coloring matters of the dye-woods. 
 M. Chevreul long since obtained the coloring matter from Bra- 
 zil-wood by the following process: 41 Digest the raspings of the 
 wood in water till all the coloring matter is dissolved, and 
 evaporate the infusion to dryness, to get rid of a little acetic 
 acid which it contains. Dissolve the residue in water, and agi- 
 tate the solution with litharge, to get rid of a little fixed acid 
 which it contains. Evaporate again to dryness, digest the 
 residue in alcohol, filter and evaporate to drive off the alcohol. 
 Dilute the residual matter with water, and add to the liquid a 
 solution of glue, till all the tannin which it contains is thrown 
 down; filter again and evaporate to dryness, and digest the 
 residue in alcohol, which will leave undissolved any excess of 
 glue which may have been added. This last alcoholic solution 
 being evaporated to dryness, leaves brezilin, the coloring matter 
 of the wood, in a state of considerable purity." 
 
 Brezilin is very soluble both in water and alcohol, but, from 
 the hardness of the wood, the coloring matter is not completely 
 extracted except by boiling; even the method recommended 
 
316 
 
 BRAZIL-WOODS. 
 
 for logwood does not dissolve all the brezilin. The decoction 
 when boiled has a deep-red color, but passes into a rich yellow- 
 red by standing. Acids give this solution a yellowish color, 
 but render it unfit for dyeing operations. Alkalies communi- 
 cate a violet color which is very fugitive: — 
 
 Protosulphate of iron . . Dark purple, not changed by 
 
 standing. 
 
 Persulphate of iron I . . Blackish-brown, permanent. 
 Chloride of tin .... Changes to a deep crimson. 
 Chloride of tin . . . With warmed liquor, a deep- 
 red precipitate. 
 Acetate of copper .... Dark purple. 
 
 Since these researches by Chevreul, M. Preisser has investi- 
 gated these substances with great minuteness, and gives it as 
 his opinion that the coloring matter of these, as well as of the 
 other woods, are oxides of a colorless base. Thus brezilin is 
 the oxide of a base which is without color, and which he terms 
 brezilein. Their compositions are : — 
 
 C. H. O. 
 
 Brezilein — Colorless base . . . =36 14 12 
 Brezilin — Colored substance . . =36 14 14 
 
 It will thus appear that the one is converted into the other by 
 absorbing two proportions of oxygen, and that the reactions 
 are allied to those of indigo and logwood already described. 
 
 The action of chromic acid, and of the chromates upon bre- 
 zilin, is remarkable; they decompose each other, and produce 
 a beautiful reddish-brown. The action of bichromate of potash 
 with the decoction of Brazil-wood has long been taken advan- 
 tage of in calico printing, and, by proper modifications, may 
 also be applied in the dye-house. The remarks upon the pure 
 coloring matter are applicable to the decoction of the wood ; 
 but the wood contains other matters (small portions of astrin- 
 gent substance), which are also soluble in the water, and which, 
 accordingly, modify to a great extent the results produced by 
 the combined action of the decoction and the pure coloring 
 principle — a circumstance which should be constantly borne in 
 mind by the dyer. It is known that decoctions of Brazil-wood 
 improve by standing, often to the extent of giving a half more 
 effect as a dye; which issupposed to be owing to the oxidation 
 and deposition of the tannin, and other foreign matters injurious 
 to the color. 
 
 The nitrates of the metals almost all destroy the red color of 
 Brazil-wood, turning it into a dirty yellow. The salts of potash, 
 soda, and ammonia, change the decoction into a rose color, 
 
SANTAL-WOOD — BARWOOD. 
 
 317 
 
 which soon passes away by standing. Alum throws down a 
 bulky red precipitate. This substance, and the chloride of tin, 
 are considered the proper mordants for Brazil-wood; but all 
 the colors obtained by this wood are exceedingly fugitive, 
 losing their brilliancy on a short exposure to the air. The sun 
 has a very powerful influence upon colors d)^ed by this wood. 
 By a short exposure, the red color assumes a blackish tint, 
 passes into a brown, and fades away into a light dun color. 
 These changes are supposed to be from the coloring matter 
 being decomposed into water and some other volatile sub- 
 stance, leaving a part of the carbon free, which produces the 
 black ; heat is also very destructive to this color; nevertheless, 
 the consumption of this species of wood is very great, espe- 
 cially for dyeing what are termed fancy reds. 
 
 Santal or Sandal-Wood, 
 
 Commonly called saunders-wood, is a native of the East 
 Indies. It differs from Brazil-wood in many of its properties ; 
 it is very hard, and gives but a weak decoction in water. 
 The coloring matter of this wood is different from that of 
 Brazil-wood ; its composition is — 
 
 Carbon. Hydrogen. Oxygen. 
 
 16 8 32 
 
 and is termed santaline. It reacts with the salts of alumina, 
 and gives red precipitates, which have more of a violet tint 
 than those of brezilin ; but it does not react in the same man- 
 ner with the chromates. Santaline is much more soluble in 
 solutions of the astringent substances than in water ; it is, 
 therefore, boiled along with sumach, and is frequently used for 
 woollens in dyeing browns and other mixed colors containing 
 red. According to the investigations of the French chemists, 
 this wood is a variety of barwood, at least the coloring matter 
 y is of trfe same composition. 
 
 Barwood. 
 
 This wood is brought principally from Sierra Leone. Its 
 coloring matter has been examined by MM. Girardin and 
 Preisser, who considered it the same as santaline. MacCulloch, 
 in his (commercial Dictionary, makes a distinction between bar- 
 wood and camwood ; but they are found to be the same in 
 chemical composition, only coming from two different places. 
 
 The following is MM. Girardin and Freisser's description of 
 this wood : — 
 
818 
 
 BARWOOD. 
 
 " This wood, in the state of a coarse powder, is of a bright- 
 red color, without any savor or smell. It imparts scarcely any 
 color to the saliva. 
 
 "Cold water, in contact with this powder, only acquires a 
 fawn tint after five days' maceration ; 100 parts of water only 
 dissolve 2.21 of substances consisting of 0.85 coloring matter 
 and of 1.36 saline compounds. Boiling water becomes more 
 strongly colored of a reddish-yellow, but on cooling it deposits 
 a part of the coloring principle in the form of a red powder. 
 100 parts of water at 212° dissolve 8.86 of substances consist- 
 ing of 7.24 coloring principle and 1.62 salts, especially sulphates 
 and chlorides. On macerating the powder in strong alcohol, 
 the liquid almost immediately acquires a very dark vinous-red 
 color. To remove the whole of the color from fifteen grains of 
 this powder, it was necessary to treat it several times with 
 boiling alcohol. The alcoholic liquid contained 0.23 of color- 
 ing principle and 0.004 salt; barwood contains, therefore, 23 
 per cent, of red-coloring matter, whilst saunders-wood, accord- 
 ing to Pelletier, only contains 16.75. ^ 
 
 16 The alcoholic solution behaves in the following manner 
 towards reagents : — 
 
 Produces a considerable yellow 
 opalescence. The precipitate 
 is redissolved by the fixed 
 alkalies, and the liquor ac- 
 quires a dark vinous color. 
 
 Fixed alkalies Tarn it dark crimson or dark 
 
 violet. 
 
 Lime-water Ditto. 
 
 Sulphuric acid Darkens the color to a cochineal 
 
 Distilled water, added in great 
 quantity 
 
 Sulphureted hydrogen 
 Salt of tin 
 
 red. 
 
 Acts like water. . 
 Blood-red precipitate. 
 
 Chloride of tin Brick-red precipitate. 
 
 Acetate of lead Dark-violet gelatinous precipi- 
 tate. 
 
 Salts of the protoxide of iron Very abundant violet precipi- 
 tates. 
 
 Copper salts Violet brown gelatinous preci- 
 pitates 
 
 . . An abundant precipitate of a 
 
 brick-red color. 
 . . Gives a light and brilliant 
 
 crimson red 
 . . Bright red flocculent precipi- 
 tate. 
 
 Chloride of mercury 
 Nitrate of bismuth 
 Sulphate of zinc 
 
DYEING WITH BARWOOD. 319 
 
 Tartar-emetic Abundant precipitate of a dark 
 
 cherry color. 
 
 Neutral salts of potash . . Act like pure water. 
 Water of barytes .... Dark violet-brown precipitate. 
 Gelatin Brownish-yellow ochreous pre- 
 cipitate. 
 Brings back the liquor to a 
 light yellow, with a slight 
 
 Chlorine \ yellowish brown precipitate, 
 
 resembling hydrated perox- 
 ide of iron. 
 
 "Pyroxylic spirit acts on barwood like alcohol, and the 
 strongly-colored solution behaves similarly towards reagents. 
 Hydrated ether almost immediately acquires an orange-red 
 tint, rather paler than that with alcohol. It dissolves 19.47 
 per cent, of coloring principle. Ammonia, potash, and soda, in 
 contact with powdered barwood, assume an extremely dark 
 violet red color. These solutions, neutralized with hydro- 
 chloric acid, deposit the coloring matter in the form of a dark 
 recldish-brown powder. Acetic acid becomes of a dark-red 
 color, as with saunders-wood." 
 
 The difficulty of its slight solubility in water is overcome by 
 a very ingenious arrangement. The coloring matter, while hot, 
 combines easily with the proto-compounds of tin, forming an 
 insoluble rich red color; the goods to be dyed are impregnated 
 with protochloride of tin combined with sumach ; the proper 
 proportion of barwood for the color wanted is put into a boiler 
 with water and brought to boil ; the goods thus impregnated 
 are put into this boiling water containing the rasped wood, and 
 the small portion of coloring matter dissolved in the water is 
 irrvmediately taken up by the goods. The water thus exhausted 
 dissolves a new portion of coloring matter, which is again 
 taken up by the goods, and so on, till the tin upon the cloth 
 has become, if we may so term it, saturated ; the color is then 
 at its brightest and richest phase. 
 
 A good deal of attention and skill is necessary to know the 
 exact point to take the goods out of the bath, otherwise the 
 dyer may either have the color poor, or, by being in too long, 
 give it a brown color. It is not, therefore, every dyer who can 
 dye a good barwood red. 
 
 In dyeing with this wood, it must be in contact with the 
 goods; the particles of the wood must mix with the fibre. To 
 have the wood in a bag, even, does not answer ; and therefore 
 great care is necessary in putting the mordanted goods into the 
 dyeing bath, that there be no loose mordant upon them ; for if 
 
320 
 
 CAMWOOD. 
 
 there is, the wood (being in the bath) will take up this mordant 
 and become dyed, and so retain a corresponding portion of the 
 coloring matter, and to that extent cause loss. Inattention to 
 this precaution is, moreover, frequently the cause of great ir- 
 regularity in the shades; and even with the greatest care, the 
 wood- grounds come out of the bath richly dyed. Barwood is 
 not used along with other matters for compound colors, in the 
 same way as the other red woods are for dyeing cotton ; but 
 it is occasionally so used in dyeing woollens. The dyer has 
 no means of testing the value of this dyewood, owing to its 
 insolubility in water. In a piece of wood as imported, we 
 found moisture 11 per cent, and only .0.5 per cent, of ash. In 
 ground samples, the moisture ranges about 20 per cent, and 
 the ash 1.2. The coloring matter is very soluble in dilute 
 ammonia. By passing ammonia water through a weighed 
 quantity upon a filter, until all soluble matters are dissolved 
 out, then drying the residue, the average of good barwoods 
 gives — 
 
 Wood remains 73.4 
 
 Water at 212° 18.2 
 
 Coloring matter 8.4 
 
 100.0 
 
 By neutralizing the ammonia, the color is precipitated as a 
 lake. 
 
 It is recommended in some works upon dyeing as a general 
 rule, that as all colors that are dyed in boilers begin to take on' 
 the dye when the solution is lukewarm, the goods should be 
 put in at that heat, and kept in till boiling. This may be best 
 in the case of woollens, and even with some colors, such as 
 barwood and madder, upon cotton ; but it is not good as a rule 
 for cotton. Generally, indeed, the quicker cotton is dyed the 
 better, and when there is a mixture of coloring matters used, 
 long working causes that color which has the greatest attrac- 
 tion for the mordant to prevail at the expense of the others, 
 even although the attraction when the goods were newly put 
 into the mixture may have been simultaneously equal and 
 mutual. 
 
 Camwood 
 
 Is another species of red-wood sometimes used in the dye- 
 house, imported from Sierra Leone. The color obtained from it 
 is more permanent, and in many instances much more beautiful 
 than from those termed Brazil-woods. The precipitates from 
 a decoction of the wood are more yellow than those afforded 
 by the Brazil-woods — which explains why the colors dyed by 
 
FUSTIC, OR YELLOW WOOD. 
 
 821 
 
 It have a certain degree of richness not obtained with the other 
 woods. It is not so easily affected by alkaline substances, and 
 appears to contain more tannin than the Brazil-woods. With 
 it — 
 
 Protosulphate of iron . . . 
 
 Persulphate 
 
 Protosalts of tin 
 
 Lead salts . . . . . . 
 
 Acetate of copper . . . . 
 
 Nitrate of silver 
 
 Perchloride of mercury . . 
 Alum 
 
 Gives a brownish-black precipi- 
 tate. 
 
 A reddish-brown. 
 
 Give the solution a very bright 
 
 carmine-red color, but little 
 
 precipitate. 
 A rich orange precipitate after 
 
 standing some time. 
 A light reddish-brown. 
 A reddish-yellow precipitate. 
 Light orange, by standing. 
 Gives the solution a beautiful 
 
 red color. 
 
 This wood may also be used for browns and other composi- 
 tion colors where Brazil-wood is commonly used ; it is more 
 soluble in water, has other advantageous properties, and may 
 be used as a substitute for many other purposes in which the 
 best Brazil-woods are employed. 
 
 Fustic, or Yellow- Wood. 
 
 This dyestuff has been long known. It is uncertain when it 
 was introduced as a dye-drug, but mention is made of it in a 
 book published in 1692. The botanical name of the tree which 
 produces this drug is Morus tinctoria. It grows spontaneously 
 in Brazil, and in several of the West Indian Islands, where it 
 attains to a great height. The wood is of a sulphur color, with 
 orange veins, and contains two coloring matters; the one resi- 
 nous, and not soluble in water; the other very soluble in this 
 menstruum, producing a deep-yellow color, having a light 
 orange cast. This substance has been long used for dyeing 
 yellow, is still extensively employed for producing that color 
 upon woollens and silk, and is the principal ingredient in dyeing 
 greens upon these substances; but it is seldom used for cotton. 
 
 The coloring matter of this wood has been studied by M. 
 Chevreui, who has given it the name of morin. If we take one 
 pound of ground fustic and boil it for a short time in a gallon 
 of distilled water, and then pass the solution rapidly through a 
 filter, to separate the woody particles; as the solution cools it 
 becomes turbid, and a quantity of the coloring matter is pre- 
 21 
 
322 
 
 YOUNG FUSTIC. 
 
 cipitated. If allowed to stand for several days, a goodly quan- 
 tity of morin may be obtained in a crystalline form. Every 
 practical dyer who has used fustic, knows that if his decoction 
 of this wood stand over, it loses its coloring properties, and that 
 therefore it should be used immediately after boiling. The 
 yellow decoction of this wood gives with the following re- 
 
 agents: — 
 
 Alkalies An orange color with a green 
 
 tint. 
 
 Protochloride of tin ... A reddish-yellow. 
 
 Perchloride of tin .... A rich yellow. 
 
 Alum A canary yellow. 
 
 Acetate of lead An orange-yellow, but dirty. 
 
 Acetate of copper .... A brown tint. 
 
 Protosalts of iron .... A greenish-olive tint ; which 
 
 darkens by standing. 
 
 Persalts of iron The same. 
 
 Sulphuric acid A red precipitate, by standing. 
 
 Nitric acid A red precipitate. 
 
 The morin precipitated from the solution, is soluble in water 
 with difficulty, but dissolves freely in a weak alkali, from which 
 it may be pi*ecipitated. The coloring matter is often found 
 crystallized in veins of the wood. The base of this coloring 
 substance is also considered to exist in the white state ; but it 
 passes into yellow by absorbing oxygen. 
 
 This dyewood was partially superseded for the dyeing of 
 yellows upon cotton by quercitron bark, and both are now 
 almost totally displaced by bichromate of potash and lead. 
 There are still, however, some greens dyed by fustic upon 
 cotton yarn. The yarn is first dyed blue by the blue vat, and 
 then passed through a little pyrolignite of alumina ; it is next 
 wrought in a hot decoction of fustic, which communicates a 
 beautiful rich shade of green. 
 
 Light cotton fabrics, as gauzes and muslins, are also occa- 
 sionally dyed green by fustic. For this purpose, the wood is 
 used in the same manner as the quercitron bark. Fustic is 
 also used with other woods for compound shades, as drabs, 
 fawns, olives, &c, and is much used with logwood in dyeing 
 black, as well on cotton as upon silks and woollens. 
 
 Young Fustic, 
 
 Called also Venetian sumach, was long used in France under 
 the name of fustet, for giving a yellow dye. These names 
 
BARK, OR QUERCITRON. 
 
 323 
 
 caused a good deal of confusion, which is to some extent ob- 
 viated by the prefix young to this wood, the yellow-wood being 
 old fustic. Young fustic is a shrub (rhus cotinus) which grows 
 principally in Italy and the South of France, where it is culti- 
 vated for the purposes of dyeing. When cut down, it is strip- 
 ped of its bark and broken into small pieces, in which state it 
 is met with in commerce. This wood contains a large quantity 
 of yellow-coloring matter named fusteric. It is soluble in water, 
 and in that state gives the following reactions with other sub- 
 stances: namely, with — 
 
 Tin salts An orange-yellow precipitate. 
 
 Iron salts An olive-green color. 
 
 Acetate of lead .... A yellowish-white. 
 
 Alkalies in solution . . Change the color to red. 
 
 This coloring matter has a strong attraction for oxygen, a 
 property which affects its use as a dye. The colors being 
 fugitive, it is seldom used alone as a dye, but as an assistant 
 to strike some particular tint. It is not used in cotton dye- 
 ing. 
 
 Bark, or Quercitron, 
 
 Is the inner bark of a tree (the quercus nigra of botanists) 
 which grows spontaneously in North America. Its dyeing 
 properties were first made known to the public by Dr. Ban- 
 croft, in 1784, and w T ere very soon appreciated. Two years 
 after he obtained an act of Parliament, vesting in him the ex- 
 clusive use and application of it for a certain term of years. 
 
 A decoction of quercitron bark has a yellow-orange color. 
 If the decoction be made very strong, it deposits a portion of 
 the coloring matter in cooling. It contains a great quantity of 
 tannin, which is always dissolved in the decoction, and which 
 gives the solution of bark a greater variety of uses. A de- 
 coction of the bark gives the following reactions with other 
 matters : — 
 
 Alkalies Deepen the color of the solution. 
 
 Lime A precipitate of a yellowish-red 
 
 color. 
 
 Protochloride of tin . . A yellowish-red precipitate. 
 
 Alum A slight precipitate cold, but 
 
 more when hot. 
 
 Acetate of alumina . . . A bulky reddish-yellow precipi- 
 tate. 
 
 Acetate of lead .... A reddish-yellow precipitate. 
 
324 
 
 BARK, OR QUERCITRON". 
 
 Acetate of copper ... A greenish-yellow precipitate. 
 
 Salts of iron Dark olive-green precipitates, 
 
 passing into brown. 
 
 Hydrochloric acid and } -r> t -n * • « « 
 
 J . A . . }• Keddish-yellow precipitates, 
 
 nitric acid . . . . ) J r r 
 
 The pure coloring matter of bark has been extracted and 
 investigated by Chevreul and Bolley. It is termed quercilrine, 
 is a crystalline substance of a sulphur-yellow color, and, like 
 the other extractive coloring matters, is considered to be the 
 oxide of a colorless base. The composition of quercitrine is 
 given as follows: — 
 
 Carbon. Hydrogen. Oxygen. Water. 
 
 16 8 9 1 
 
 A decoction of bark standing until it becomes stale, loses much 
 of its dyeing properties. The yellow matter is deposited, and 
 what remains in solution is of a darker hue, and gives a dull 
 color when used for dyeing. 
 
 Bark was extensively used in the dye house for many years 
 for the purpose of dyeing yellow, and almost completely super- 
 seded the use of fustic, both from its beauty and also its cheap- 
 ness; but its use for that purpose has been superseded by the 
 bichromate of potash. Its principal use now in the cotton dye- 
 house is to form the ground for certain browns, and for dyeing 
 green upon light muslin cloth ; but catechu has now nearly 
 superseded it for browns. The quantity of tannin combined 
 with it makes it very useful for olives; goods impregnated 
 with iron, and passed through a decoction of bark, take a beau- 
 tiful olive. When used for dyeing green, the mordant em- 
 ployed is acetate of alumina; but for yellow, which is now 
 only dyed upon yarn for particular purposes, the mordant used 
 is chloride of tin (spirits). 
 
 When bark is used for brown upon yarns, it is done thus: 
 The goods are dyed a deep yellow by being steeped in sumach, 
 and then passed through the spirits, out of which they are 
 wrought in a boiling decoction of bark, raised with spirits ; that 
 is, having a quantity of spirits put into the bark solution. 
 The goods are washed from this, and afterwards passed through 
 a mixture of logwood and Brazil-wood, according to the shade 
 of brown required. And we would here draw attention to a 
 very interesting fact, observed first by Mr. Thorn, of Manches- 
 ter, namely, that amongst the coloring matters and bases there 
 is an elective affinity, which, if not studied, will lead to several 
 errors. We quote on this subject from ParnelTs Applied Che- 
 mistry : — 
 
 u But the combinations of alumina, &c, with soluble color- 
 
FLA VINE. 
 
 325 
 
 ing matters seem to be cases of true chemical combination, 
 taking place in definite proportions, and under the influence of 
 different degrees of attractive force for different coloring prin- 
 ciples. Thus, alumina has a stronger attraction for the coloring 
 principle of madder than for that of logwood, and a stronger 
 attraction for that of logwood than for that of quercitron. 
 When a piece of cloth impregnated with alumina is immersed 
 into a decoction of quercitron bark, it acquires a fast yellow 
 color; if the same cloth is washed for some time and kept in 
 a hot decoction of logwood, the alumina parts with the color- 
 ing principle of quercitron to combine with that of logwood, 
 and the color of the cloth becomes changed from yellow to 
 purple. If the same cloth is next immersed for a few hours in 
 a hot infusion of madder, the alumina parts with the coloring 
 principle of logwood to unite with that of madder, the color 
 of the cloth changing from purple to red. The quantity of 
 alumina on the cloth does not appear to diminish while these 
 substitutions are taking place. These interesting facts were 
 communicated to me by Mr. John Thorn, of the Mayfield Print 
 Works." 
 
 Now, the same law is applicable when the mordant is tin ; 
 so that a quantity of goods being dyed yellow as described, 
 and then put into a hot solution of logwood, a quantity of the 
 yellow is displaced by the coloring matters of the logwood and 
 Brazil-wood. Every dyer knows when he has browns of a 
 deep shade, how difficult it is to bring them up, should he fail 
 to strike the proper tint at the first dip ; if he is necessitated 
 to continue working in the logwood and Brazil-wood, he is 
 very apt to run his color poor in yellow by dissolving it off; 
 and to remedy this evil he next adds fustic or bark, with very 
 questionable success. We have often experienced these diffi- 
 culties when dyeing browns by the process described above, 
 with an aluminous mordant upon the cloth instead of tin. 
 
 Flavine. 
 
 Within these few years a vegetable extract bearing this name 
 has been introduced into the art. It is brought from America 
 in the state of an impalpably fine powder, very light, and of a 
 dun color. It is used in the dye-house as a substitute for quer- 
 citron bark, to which, for some purposes, it is superior. The 
 mode of preparing it is by dissolving it in hot water, with 
 which it gives a sort of turbid solution. It should be used 
 when newly dissolved ; for if allowed to stand, it deposits a 
 brownish-yellow mass, in consequence of its not being all com- 
 
326 
 
 WELD, OR WOLD. 
 
 pletely soluble in water. If boiled in distilled water until all 
 the soluble matter is taken up, and the clear solution decanted, 
 it soon yields a deposit. The color produced by flavine is 
 never good until raised. A color dyed by it weakens gradually 
 when a little sulphuric acid has been added; but what remains 
 retains its brilliancy by raising, and in respect of this property 
 it differs from bark. 
 
 The quantity of coloring matter in flavine is very great ; its 
 value as compared with bark is as 16 to 1, or one ounce of 
 flavine is equal to one pound of bark. A portion burned left 
 4.4 per cent, of ash; and a solution of it gives the following 
 reaction with salts: — 
 
 Persalts of iron . . . Olive-black precipitates. 
 
 Protosalts of iron . . . Deep greenish-black precipitates. 
 
 Protosalts of tin . . . Lemon-yellow precipitates. 
 
 Persalts of tin . . . . Orange-yellow precipitates. 
 
 Alumina A rich yellow precipitate. 
 
 Acids lighten the color of the solution, and alkalies deepen 
 it, rendering it redder. 
 
 Extracts of Woods. 
 
 In order to save the cost of transportation, and at the same 
 time give more regular and more easily applied products, the 
 coloring matter of dye-woods has for many years been sold in 
 the form of liquid and solid extracts. The latter are obtained 
 by drying in vacuo the colored solutions. 
 
 The decoctions of Brazil wood, according to Dingier, are 
 considerably improved by removing a fawn substance, by 
 means of a small quantity of milk without cream added to the 
 boiling liquors. The caseine of the milk coagulates and falls 
 to the bottom of the pan with the impurity. 
 
 It is also said, that ground logwood or Brazil wood, damp- 
 ened with a water holding in solution some gelatine (2 per cent, 
 of the weight of the wood), -and allowed to rest for several 
 days, will give colored solutions, much better in quality and in 
 amount of dyeing power, than woods treated with water alone. 
 
 Weld, or Wold. 
 
 This vegetable is extensively cultivated in France, and many 
 other parts of Europe, for the purpose of dyeing yellow. It is 
 found in commerce in small dried bundles. The more slender 
 the stem is, the better is it considered for dyeing. Both the 
 
WELD, OR WOLD. 
 
 327 
 
 seeds and the stems are used, as they both contain the coloring 
 matter; bat the seeds are considered to contain it in greater 
 quantity. The coloring matter approaches very nearly to that 
 of quercitron in chemical properties; and of all the vegetable 
 dyes it is least acted upon by acids and alkalies, which gives 
 to the dye, so far as these substances are concerned, great per- 
 manence. But it has this counteracting disadvantage, that 
 the color rapidly fades or passes away when exposed to the 
 action of air and light; it then becomes oxidized, and in con- 
 sequence has been abandoned for almost all purposes where 
 bark can be used. It is still, however, occasionally used as a 
 yellow dye for silks and woollens, and also for some mixed 
 colors. A decoction from weld is made in the same way as 
 that of most other vegetable dyes; the wood, whether in bunches 
 or chipped, is merely put into a boiler with water and boiled. 
 Sometimes the bunches are put into a bag of coarse cloth. 
 This decoction is of a yellow color, with a reddish tint, and has 
 a bitter taste and a peculiar odor: — 
 
 Alkalies .... Change it to a brighter yellow. 
 
 Acids Darken the yellow. 
 
 Alum A yellow precipitate. 
 
 Protochloride of tin A yellow precipitate. 
 
 Acetate of lead . . A yellow precipitate. 
 
 Sulphate of iron . A yellowish-olive precipitate. 
 
 The coloring matter of this dye has been obtained in needle- 
 shaped crystals by sublimation, and is then termed luteoleine. 
 We have referred to a use to which weld is applied in the 
 making up of pastel and woad vats (page 297). The weld was 
 long used as a dye for woollens and silk before it was used for 
 cotton; its introduction as a dye for this substance is connected 
 with a clever fraud. "In the year 1773, the sum of £2000 
 was granted by act of Parliament to a Dr. Williams, as a re- 
 ward for his discovery of a fast green and yellow dye upon 
 cotton-yarn and thread. This supposed fast dye was given by 
 the combination of weld with a certain mordant, the composi- 
 tion of which the patentee was permitted to conceal, that foreign- 
 ers might not enjoy the benefit of his discovery; while he on 
 his part engaged to supply the cotton and thread dyers with 
 his dye at a certain fixed price. The mordant used was sup- 
 posed by chemists to be a solution of tin alone, or of tin and 
 bismuth, which gives to weld-yellow the power of resisting the 
 action of acids and of boiling soapsuds, although it is not proof 
 against the continued action of the sun and air. This defect, 
 however, was not easily discernible, in consequence of the in- 
 genious method which, according to Dr. Bancroft, the -inventor 
 
328 
 
 TURMERIC — PERSIAN BERRIES. 
 
 employed to obtain a favorable testimony of the dyers upon 
 the subject. He caused his specimens of dyed yarn to be 
 woven into pocket-handkerchiefs, and gave them to be worn in 
 the pockets of those who were afterwards to attest to the good- 
 ness of his dye; and, as handkerchiefs worn in pockets were 
 not exposed to the action of the sun and air, this want of per- 
 manence was not discovered until some time after the reward 
 had been paid for an invention which proved of little or no 
 value." 
 
 Turmeric. 
 
 This is another substance formerly used in dyeing. It is 
 principally brought from the East Indies and from China. It 
 is the roots of a plant named curcuma langa, and resembling 
 ginger; it is reduced to powder, and in this state is met with 
 in the market. The coloring matter is extracted by boiling in 
 water; and decoctions of it have a peculiar smell and bitter 
 taste. The color is very fugitive, fading rapidly in the air; 
 and there is no proper mordant for it. We have occasionally 
 seen it used for giving a peculiar tint to greens and light browns; 
 but this only could serve for a short time. The coloring prin- 
 ciple of this vegetable has also been extracted, and is known 
 in chemistry under the name of curcumme. A decoction of 
 turmeric, or paper dyed with it and kept from exposure, is 
 much used in testing for the presence of alkalies^ which give 
 to the dye a red-brown color. 
 
 Persian Berries. 
 
 These berries are the root »of the rharnnus tinctoria, a plant 
 growing in the Levant and South of France, &c. They yield 
 a bright-yellow color, used by artists and occasionally by dyers ; 
 but the dye is very fugitive. There are two kinds of Persian 
 berries; one large, plump, and clear in color, the other small, 
 wrinkled, and brown. The coloring matter of each kind has 
 also certain distinctive properties, caused, it is believed, by the 
 one being in full maturity, the other unripe. The large and 
 mature berries are the best, giving a greater quantity of dye, 
 and a superior quality of color. The coloring matters ex- 
 tracted from the two varieties are named ckryso-rhamnine and 
 xantho-rhamnine. These have some interesting reactions with 
 bichromate of potash, and other oxidizing agents. 
 
SAFFLOWER, OR CARTHAMUS. 
 
 S29 
 
 Safflower, or Carthamus. 
 
 This is an annual plant, cultivated in Spain, Egypt, and the 
 Levant. There are two varieties of it, one having large leaves, 
 and the other smaller ones ; the latter is the best. It is only the 
 flower of this plant that is used for dyeing. When the flowers 
 are gathered, they are squeezed between two stones to express 
 their juice; they are afterwards washed with spring water; 
 next taken in small quantities and pressed between the hands 
 and laid out upon mats to dry. These cakes are covered up 
 during the day to prevent the sun from shining upon them — 
 which would not only destroy the color, but dry the cakes too 
 much, and thereby cause further deterioration. They are kept 
 exposed to the dews of night, and turned over occasionally, 
 till dried to the proper point, when they are packed up for the 
 market. It is in this state they are procured by the dyer. 
 
 Safflower contains two coloring substances. The one is yel- 
 low, very soluble in water, and of no use to the dyer. To free 
 the safflower from this yellow-coloring substance is a particular 
 part in the manipulation of this dyestuff. The other coloring 
 substance is red, and is extracted from the vegetable after the 
 yellow substance has been washed away, by means of alkaline 
 carbonates. This substance is used very extensively for dye- 
 ing the various shades of pinks, crimsons, roses, &c, upon silk, 
 and also for the same colors upon cotton, with lavender, lilac, 
 and pearl-white. The mode of preparing safflower for the pur- 
 pose of extracting the red matter from it, was for a long time 
 that recommended by Berthollet, and followed by all other 
 writers upon the subject; namely, putting a quantity into a 
 fine bag, "tramping" it with the feet in water until the yellow 
 color was dissolved and washed away; the mass left was then 
 treated with an alkali to extract the red matter. But although 
 this red-coloring matter is insoluble in water, it will be found 
 that the bag in which it is tramped becomes a deep crimson- 
 red, which can only be produced by its imbibing this red mat- 
 ter. It proceeds, we think, from a very fine powder, probably 
 carthamine, adhering to the stuff like the pollen of the flower, 
 and which floats away in the water. It is much heavier than 
 the ordinary carthamine, and collects as a sediment at the bot- 
 tom of the vessels used to hold the safflower; but when tramped 
 in bags, this powder is expressed and imbibed by the bag, 
 which becomes strongly dyed, thereby causing a loss of the 
 dye. To avoid this, the safflower is now put into a tub with- 
 out any bag, with as much water as will cause the whole to 
 float freely. A very little tramping or agitation is sufficient to 
 
330 
 
 SAFFLOWER, OR CARTHAMUS. 
 
 reduce the cakes to a soft flocculent mass, which is the sole use 
 of tramping. It is next removed to a cask or tub, provided 
 with a false bottom, covered with fine haircloth. In the lower 
 or true bottom, is a plug-tap. This vessel is filled with clean 
 water, which is let out by the ping at the bottom; it is filled 
 again, and so on, until the water passing through is not colored 
 yellow. After this, there is put into it a measured quantity of 
 pure water — about three gallons to the pound of safflower — in 
 which is dissolved a little carbonate of soda, or carbonate of 
 potash (pearlash does well), about an ounce to the pound of 
 safflower. Some kinds require less than others ; but care ought 
 to be taken that too much is not used, as it destroys the bright- 
 ness of the color. This, being dissolved in water, is put into 
 the tub containing the safflower, well stirred, and allowed to 
 stand for about seven hours; the ping is then taken out, and 
 the clear liquor drawn into a proper vessel. This liquor con- 
 tains the red dye which has been extracted by the alkali. The 
 remaining safflower is afterwards washed by pouring upon it a 
 little more water made slightly alkaline, and allowed to steep 
 a short time; but if fine light colors are to be dyed directly 
 from the solution, this second extract does not answer so well, 
 as the shade is not so pure. This second extract is commonly 
 kept and used instead of clear water for the next parcel of 
 safflower; or, if it is not wanted for this purpose, a little acid is 
 added to the liquor, and a piece of old cotton is allowed to 
 steep in it until it has extracted all the coloring matter, which 
 is afterwards recovered for use, as will presently be described. 
 
 The liquor extracted from the safflower contains both red 
 and yellow-coloring matter. For this reason silk goods are 
 not dyed directly by this extract, as the silk takes up a por- 
 tion of the yellow, which renders the color more of a brick hue 
 than is due to the rose and pink. To dye silks, any old cot- 
 ton yarn is dyed first by the safflower extract; the cotton takes 
 up nothing except the red. This cotton is then thoroughly 
 washed in cold water till the water coming from it is perfectly 
 clear; it is then steeped for a little in water made slightly alka- 
 line by carbonate of soda or potash, which extracts the red 
 from the cotton, and forms the dyeing solution for silk. The 
 silk to be dyed pink, generally receives a bottom, or ground, by 
 passing it through a weak solution of cudbear or archil, so as 
 to form a flesh or light lavender color — the depth being regu- 
 lated according to the shade of pink wanted. It is then put 
 through the safflower solution, which must previously be ren- 
 dered acid by a little lemon-juice, vinegar, or sulphuric acid. 
 When the safflower liquor is exhausted, the silk is washed in 
 cold water, and finished by passing through a little water made 
 
SAFFLOWER, OR CARTHAMUS. 
 
 331 
 
 acid by lemon-juice or tartar; neither vinegar nor sulphuric 
 acid should be used in the finishing process. 
 
 To dye cotton pink, the liquor is used as extracted from the 
 vegetable; the goods require no previous preparation, except 
 to be well bleached. The quantity of liquor used varies accord- 
 ing to the shade required; one pound of safflower to the pound 
 of cotton gives a dark rose; and the other shades in propor- 
 tion, according to the tint required. 
 
 The goods are first wrought in the alkaline solution for five 
 or six minutes, and then taken out, and vitriol added to the 
 solution until it tastes decidedly sour; the goods are again im- 
 mersed, and kept working in this till the solution is perfectly 
 exhausted. The ascertaining of this point requires a little ex- 
 perience, as exhaustion is known by the operator holding a 
 little between him and the light; when, if there is no tinge of 
 red, the solution is spent. The goods are now to be well washed 
 by passing them through three or four tubsful of clear cold 
 water; they are then finished by passing them through a little 
 water, with just sufficient tartar to make the liquid taste sour. 
 
 It must be borne in mind that, in dyeing with saffiower ; the 
 water ought to be pure and always cold ; a very little heat 
 destroys the beauty of the color; the goods ought also to be 
 dried cold, and preserved carefully from sunshine. The colors 
 obtained by safflower are the prettiest that can be had upon 
 cotton, but they are fugitive. 
 
 The most beautiful lilacs, puces, and lavenders, are obtained 
 by safflower and Prussian blue; but it is one of the most diffi- 
 cult colors to produce of equal shade. The goods are generally 
 first dyed a blue by nitrate of iron and prussiate of potash (see 
 page 159), and then put through the safflower solution, previously 
 made acid ; but the rapidity with which the cloth takes up the 
 red, renders it almost impossible to get a perfectly even dye. 
 Another method is to dye the cloth in the first instance pink, 
 and then to dye it blue. This method gives a more equal dye, 
 but it is liable to serious objections. The nitrate of iron used 
 acts upon the coloring matter, oxidizing and destroying its 
 beauty and depth, thus causing loss, and making this color ex- 
 ceedingly expensive. Persulphate of iron may be used instead 
 of the nitrate, as it is not so corrosive, and will preserve the 
 tint of the safflower much better. 
 
 We mentioned in our introductory remarks that one essen- 
 tial condition in all dye-drugs, before they could be used as 
 such, was that they should be in solution ; but carthamus is an 
 exception to this rule; when it is in a soluble state, it is not a 
 dye, and must be rendered insoluble before it will act as such. 
 Although the cotton is generally passed through the alkaline 
 
332 
 
 SAFFLOWER, OR CARTHAMUS. 
 
 solution before acid is added, still this will not produce the dye, 
 but merely secures an equalized color under the rapid action 
 with which the fibres imbibe the solid coloring matter after 
 acid is applied. 
 
 This fact favors the opinion that the cotton imbibes the 
 coloring matters in the same way as they are imbibed by char- 
 coal — the fibres of the cotton, like those of silk and wool, being 
 hollow. 
 
 This action is not merely a capillary attraction, such as 
 shown with glass tubes. When very small glass tubes are 
 placed with their ends dipping into a solution, the fluid is 
 observed to rise in them to a great height inversely as the hol- 
 low diameters of the tubes, and then remain stationary; but 
 if such tubes are placed in a vessel containing the carthamus 
 in suspension, although they become filled with the liquor, 
 they do not exhaust the liquor of the suspended coloring mat- 
 ter; whereas the fibres of the cotton, put 
 into this fluid, extract all the coloring mat- 
 ter from the water, and become literally 
 filled with it. Thus, if we take a vessel 
 filled with water, having in it carthamus 
 rendered insoluble by an acid, and suspend 
 a skein of cotton in it for a few hours, the 
 cotton will absorb the whole coloring mat- 
 ter, and leave the solution clear — indicating 
 thereby a distinct power of attraction ex- 
 ercised between the fibre and coloring par- 
 ticles, and also a circulation of the fluid 
 through the fibre or tubes of the cotton, which indeed is true, 
 more or less, of any solid substance so finely divided as the 
 carthamus, and diffused in water along with fibres of cotton. 
 In the case of precipitates, the more dense they are the smaller 
 is the quantity of solid matter imbibed by the fibre. 
 
 When a little safflower solution has an acid put into it, and 
 is allowed to stand for a time, the red carthamine precipitates 
 as a fine red lake, and is sold as such, adhering to saucers, for 
 dyeing ribbons, &c. An extract of safflower has also been 
 recently introduced into the market for the use of dyers, but 
 we have, as yet, had too little experience of its use to speak of 
 it with confidence. 
 
 Although safflower colors may be the most simple and easily 
 dyed of all kinds, still, from their delicate reactions with other 
 matters, there are few substances subject to so much risk of 
 being destroyed. If the water is not pure they will dry brown. 
 A little acetic acid, cream of tartar, or tartaric acid, is generally 
 added to the last water from which they are finished to preserve 
 
 Fig. 14. 
 
MADDER. 
 
 333 
 
 the tint; but too much or too little of these will produce per- 
 ceptible effects upon the shades. Great care has to be taken 
 in the drying; it should be done in a perfectly dry stove, not 
 hot, and having ample space between each parcel, as a very 
 little steam produces a yellow surface. The goods are generally 
 dried in the cold; but care is necessary that no sun rays touch 
 them ; also that they are not injured by steam or smoke enter- 
 ing the sheds where they are drying. If all necessary pre- 
 cautions are not taken, the dyer has the mortification, as well 
 as expense, of putting the goods through at least the last acid 
 solution, and if they are much touched, he is obliged to redye 
 them. 
 
 The view that carthamine, or the red-coloring matter of saf- 
 flower, is the oxide of a colorless base, as in the case of the woods 
 we have referred to, has been objected to by many investiga- 
 tors, whose experiments and reasoning bear evidence of care 
 and judgment; thus adding an interest to the subject of vege- 
 table coloring matters, and showing the practical man that 
 there is yet before him much to be discovered, and that a care- 
 ful observation of all the reactions and circumstances connected 
 with his operations will stand a fair chance of being rewarded 
 with success. 
 
 Madder. 
 
 This vegetable rivals indigo as a dye-drug, both from the 
 beauty and permanence of the colors it produces, and also 
 from the variety of shades which it is capable of furnishing by 
 the combinations of its coloring matters. It is the root of a 
 plant or shrub called rubia tinctorum, cultivated in the Levant, 
 and in several western countries of Europe, especially in France 
 and Holland. The East Indies also furnish a quantity of it, 
 and within a few years past a large importation has taken place 
 of a species termed rubia memsgista, which contains much more 
 coloring matter than the best madders of Europe. Its culture 
 has often been attempted in England, but without success. In 
 the Levant the madder is collected only once in five years ; but 
 in France it is gathered every three years. It is only the root 
 of the plant that is used for dyeing. In removing the root 
 from the ground, it is carefully cleaned, and, when the season 
 is favorable, it is spread out in the air to dry. French madder 
 is generally more imperfectly dried than that from the Levant, 
 and consequently contains more water of vegetation, and to 
 , that extent it is comparatively less valuable. It is sometimes 
 dried in a stove, to allow it to pulverize. The dryness of the 
 
334 
 
 MADDER. 
 
 article is judged of by the fracture when a piece of the root is 
 broken transversely by bending it. 
 
 When the roots are perfectly dry, if they are broken or cut 
 with a knife, they present to the eye a reddish-yellow color, 
 which passes to a dense brownish-red when the piece is mois- 
 tened ; but the more yellow the root appears when dry, the 
 more coloring matter does it yield. Madder, when fresh, and 
 after being cut or ground to powder (in which state it is gene- 
 rally used by the dyer), has a heavy sweet smell, with a some- 
 what earthy flavor. The product of grinding is generally of 
 three kinds. The first is formed of the epidermis, or skin of 
 the roots, and comes off in fine filaments by slight pressure. 
 This is collected separately, and forms what is termed the mull 
 — which is of very inferior quality. The second consists of the 
 annular portion of the root; and the third of the ligneous or 
 centre portion ; but generally these two qualities are mixed. 
 
 The varieties of madder in commerce are distinguished by 
 the name of the country from whence they are brought, and 
 by the appearance they receive in the preparatory process 
 through which they pass previous to their reception at the dye- 
 house. 
 
 Levant Madder is in the form of shoots or fibres, of greater 
 or less length, and very slender; brown externally, and pale 
 orange-red internally. It is merely cleaned of earth and dried, 
 and is imported from Smyrna, Cyprus, &c. 
 
 Dutch Madder is ground, but so very coarsely as to enable 
 the buyer to judge of the nature of the root from which it is 
 prepared. It has a greasy feel, and a strong nauseous odor. 
 Its color varies from a brown to an orange-red ; the brown is 
 inferior. It becomes damp when exposed to the air, a property 
 which can be taken advantage of to judge of its quality; if a 
 little of it is exposed in a damp place, when good, its color 
 passes from the brownish-orange tint to a deep red. 
 
 The madder of Holland is said to be cropped or uncropped, 
 according as the barky matter of the root is separated or not, 
 from the ligneous part in the process of pounding through 
 which it passes. This madder is never employed fresh, but is 
 kept at least a year, and it is better to be kept three years 
 before it is used. It may be kept several years longer without 
 being impaired. During the first years it is kept, it undergoes 
 some internal change, and becomes much brighter in color; 
 the powder adheres together, forming a mass very difficult to 
 remove from the cask, and swells so that the bottom of the 
 cask often assumes a convex form. If kept for too long a time 
 it becomes deteriorated ; the portion in contact with the cask 
 loses its brilliancy, and becomes brown, and this change grad- 
 
MADDER. 
 
 335 
 
 ually extends through the whole mass. After this change has 
 taken place, it is unfit for dyeing fine reds or light tints, and 
 can be used only for dark colors. 
 The marks of Dutch madder are — 
 
 Alsace Madder. — This madder is met with in commerce in 
 a state very similar to that of Dutch madder ; but although 
 the operation of cropping is generally performed upon it, that 
 term is not used in designating it. It readily absorbs mois- 
 ture from the air, and also acquires a deep-red tint when ex- 
 posed in a damp atmosphere, as that of a cellar. Like Dutch 
 madder, it is not employed fresh ; it is in its best condition 
 when about two years kept, but it deteriorates much sooner by 
 keeping, and also agglomerates into a mass, and swells. It is 
 inferior to the madder of Holland ; its odor is more penetrating, 
 and its taste less sweet, but with an equal degree of bitter ; its 
 color is more yellow, passing into brown, with much less of 
 the orange tint. A little experience in comparing the two 
 sorts soon enables the dyer to distinguish the one sort from the 
 other. 
 
 Madder of Avignon. — This madder is deservedly much 
 esteemed. There are several varieties of it, some due merely 
 to the modes of preparation, and others to the soil on which 
 the plant grows. It is ground into a fine powder, which feels 
 dry to the touch, and does not absorb moisture so readily as 
 the other kinds of madder; but when exposed to a humid at- 
 mosphere, it also undergoes a change. Its odor is very agree- 
 able; the taste a mixed sweet and bitter, the last predominat- 
 ing; and its color varies from a pink or rose hue to a deep 
 red, or reddish-brown. The best qualities are obtained from 
 those roots which grow in marshy or swampy ground, and 
 places enriched by admixture of animal or vegetable matters. 
 The roots from such a soil are generally of a deep red color, 
 while those from less favorable grounds are of a rose or pink 
 tint. It is by mixing these kinds in different proportions that 
 the variety of madders from this locality are obtained. The 
 several qualities have various marks, besides the ordinary 
 marks, as — 
 
 P. to signify . . . Palus (marshy). 
 
 R. — ... Roseate, 
 
 P.P. — ... Pure palus (marshy). 
 
 R. P. P. — ... Purest red pa lus (marshy). 
 
336 
 
 MADDER. 
 
 The actual commercial marks, according to the order of their 
 quality, are — 
 
 S. F. for superfine — containing all the matter of the root. 
 S. F. F. for fine superfine — containing all the ligneous matter 
 of the root, the mull or bark, or outside portion 
 being separated. 
 E. S. F. F. for extra fine fine — containing the heart, or centre of 
 the root, and the internal part of the oily ring 
 which surrounds it; being also twice sifted so as 
 to separate completely from the mull, &c. 
 
 These three varieties may themselves vary according to the 
 nature of the roots, and the manner in which they are dried, 
 and otherwise prepared ; but it is from these that all the va- 
 rious mixtures are made ; and the tact of the manufacturers 
 consists in mixing them so as to produce the qualities required 
 by the consumer. 
 
 Avignon madder can be used fresh, although it is better to 
 be kept for twelve months. It does not cake or agglomerate 
 in the cask, but when kept too long it becomes deteriorated in 
 quality, undergoing the same kind of decomposition as the 
 other madders. 
 
 Madder is often adulterated by mixing with it brickdust, 
 red or yellow ochres, sand, and clay, or by adding sawdust of 
 certain woods, as mahogany, logwood, sandal-wood, &c. &c. 
 The mineral adulterations may be detected by putting some of 
 the suspected madder in a large glass vessel, and adding to it 
 a quantity of pure water; the madder floats, and the mineral 
 adulterations sink to the bottom. We thus readily obtain an 
 approximate idea of the quantity of adulterating matters pre- 
 sent, and by carefully removing the floating madder, and then 
 filtering the liquor, the mineral substances may be separated 
 and weighed. We may also proceed by burning a small por- 
 tion of the madder and seeing the ash that remains; we have 
 in this way tried various samples, having 8J per cent, of ash. 
 
 When the adulterants consist of sawdust or other ground 
 vegetable matters, their detection is much more difficult; in- 
 deed, the only means likely to be at all successful, is to weigh 
 a portion of the suspected madder, and to try its coloring pow- 
 ers by a piece of prepared cotton; except where chemical skill 
 can be applied, the coloring matter of the madder can be ex- 
 tracted, and compared with other known qualities. 
 
 Some of the French d^ers use a colorimeter for judging of the 
 quality of their madder. It depends upon a principle similar 
 to that of Mr. Crum's chlorimeter for testing the strength of 
 bleaching powder (see page 87). A weighed quantity of mad- 
 
ALIZARIN. 
 
 337 
 
 der of known quality is boiled, and the decoction is put into 
 a glass vessel; similar quantities of the madders to be tried 
 are treated in the same manner, and placed in a glass vessel of 
 similar size and form, and the tint of color is judged by com- 
 parison. Of course, the test solution may be diluted by a 
 measured quantity of water, and by using a graduated glass, 
 their comparative values, estimated by the rate of dilution, &c, 
 may be easily ascertained. But this method is subject to many 
 errors, as when any adulteration has been practised on the 
 madder by addition of other vegetable coloring matters, such 
 as sapan-wood, &c. 
 
 Madder has been the subject of a great many chemical in- 
 vestigations, the study of which is highly useful to those who 
 use this dye-drug in their operations.* The first investigation 
 into the chemical properties of madder led to the discovery of 
 two distinct coloring matters — one yellow, which is very solu- 
 ble in cold water, and named xanthin ; the other red, mode- 
 rately soluble in hot water, is called alizarin. Several methods 
 of extracting alizarin by sulphuric acid have been proposed, 
 but the following is probably the most simple in practice : 
 "One pound weight of madder is mixed up with an equal 
 weight of concentrated sulphuric acid, the vessel so closed up 
 that no heat is evolved, and allowed to stand in a cool place 
 for three or four days ; by this process all the constituents of 
 the madder are converted into charcoal, except the alizarin. 
 When this charring process is completed, the mixture is care- 
 fully dried, and then digested in alcohol, which dissolves the 
 alizarin and leaves the charcoal. The solution may now be 
 diluted with water, and put into a retort, and kept at a heat of 
 170° Fah. ; the beak of the retort being connected to a receiver, 
 the alcohol distils over and is recovered. Water and alizarin 
 remain in the retort, which being poured out and filtered, the 
 alizarin remains upon the filter in a state of great purity. It 
 is of a beautiful red color, and gives the same color to boiling 
 water." 
 
 Alizarin is soluble in turpentine, naphtha, and fat oils; 
 chlorine turns it into a yellow-brown ; sulphuric acid dissolves 
 it, and, at the same time enlivens the color ; muriatic and 
 nitric acids both dissolve it, changing the color from red to 
 yellow. 
 
 Alkalies . . . .A violet color. 
 
 Alumina .... A deep red-brown precipitate. 
 
 Oxides of tin . . . Precipitates of the same appearance. 
 
 * See 2d, 5th, and 6th vols. Chemical Gazette ; 1st vol. of Pharmaceutical 
 Times ; 33d vol. Phil. Magazine, &c. ; Thomson's Vegetable Chemistry. 
 
 22 
 
338 
 
 MADDER. 
 
 Phosphates have a very powerful attraction for alizarin, so 
 much so, that when animals take any madder into their system, 
 the bones, which contain a considerable quantity of phosphates, 
 become colored red. This fact is well known to dyers who 
 are in the habit of using madder in their operations, and neces- 
 sarily often tasting it. When taken in quantity, the urine is 
 colored by it. 
 
 From the above reactions of alizarin with other substances, 
 it was supposed that it constituted the true coloring of madder ; 
 and means were soon adopted to separate this coloring matter 
 from the vegetable, and use it pure ; but it was afterwards 
 found that a fixed dye could not be obtained by pure alizarin, 
 and therefore it did not constitute all that was required in giv- 
 ing the dye. This led to further investigations, productive of 
 further discoveries respecting these coloring matters. It finally 
 appeared that madder has five different coloring matters, which 
 have been named — 
 
 Madder purple, 
 Madder red, 
 
 Madder orange, 
 Madder yellow, 
 
 Madder brown ; 
 
 each of which may be obtained by the following operations : — 
 Madder Purple. — The madder is washed in water at about 
 summer heat, then boiled in a strong solution of alum for an 
 hour; the clear liquor is afterwards decanted, and sulphuric 
 acid added, which precipitates the madder purple along with a 
 number of impurities. These are removed by washing with 
 boiling water, then with pure muriatic acid, and afterwards 
 dissolving in alcohol. Madder purple is soluble in hot water; 
 and if pure it gives the water a dark-pink color. If the water 
 contains lime, a great part of the coloring matter is precipi- 
 tated as a reddish-brown substance. Cotton, saturated with 
 the acetate of alumina, is dyed a bright red, provided the 
 quantity of madder purple be not too great for the aluminous 
 base, but if so, the color will have more of a purple tint. A 
 boiling solution of alum forms with the madder purple a 
 cherry -red solution ; caustic potash forms with it a fine yel- 
 lowish red color; the carbonates of potash and soda have a 
 similar effect ; and sulphuric acid produces a bright red or rose 
 color. 
 
 Madder Eed is separated from madder purple in conse- 
 quence of its not being soluble in a strong solution of alum. 
 It is obtained by boiling madder in a weak solution of alum, 
 by which a reddish-brown precipitate is obtained. This pre- 
 cipitate is repeated and boiled in pure muriatic acid, then 
 
COLORING- MATTERS. 
 
 339 
 
 washed carefully with water and boiled in alcohol. This dis- 
 solves both madder red and madder purple ; but, by gently 
 evaporating the alcoholic solution until it is very much con- 
 centrated, and then allowing it to cool, an orange-colored pre- 
 cipitate is formed, which is collected and repeatedly boiled in a 
 strong solution of alum, as long as the alum solution comes off 
 colored ; the insoluble portion is madder red. It is a yellow- 
 ish-brown powder, and imparts to cotton, impregnated with 
 acetate of alumina, a dark-red color, when in excess; but if the 
 mordanted cotton be in excess, a brick-red color is produced. 
 Caustic potash gives a violet, carbonate of soda a red, and sul- 
 phuric acid a brick-red solution. 
 
 Madder Orange is distinguished from the former two colors 
 by its slight solubility in alcohol. It is prepared by macera- 
 ting madder for twenty-four hours in distilled water, the infu- 
 sion being strained off and allowed to repose a few hours. The 
 liquor is carefully decanted and filtered through a paper filter, 
 upon which the madder orange remains. It may be washed 
 with cold water, and afterwards purified by spirits of wine, in 
 which it is not soluble. It is a yellow powder, soluble in boil- 
 ing water, and imparts to cotton impregnated with an aluminous 
 mordant a bright orange color, when in excess. A boiling solu- 
 tion of alum forms with madder orange a yellow solution ; 
 caustic potash gives a dark rose, carbonate of soda an orange, 
 and sulphuric acid an orange-yellow color. 
 
 Madder Yellow is characterized by its great solubility in 
 water. It is a yellow gummy mass, communicates to mor- 
 danted cotton a pale-nankeen color, but does not of itself form 
 a true dye. Madder which contains much of this ingredient 
 is of inferior quality, as the yellow becomes so incorporated 
 with the other colors as materially to deteriorate them, and to 
 require several operations to free the goods from it afterwards. 
 
 Madder Brown is a brownish-black dry mass, obtained in 
 the preparation of the other coloring matters. It is neither 
 soluble in water nor alcohol, is of no importance as a dye-drug, 
 and does not enter into any of the colors dyed by madder. 
 
 ' Madder Acids. — Besides these five coloring matters, mad- 
 der contains two acid substances, named madderic and rubiacic 
 acids. They have no known dyeing properties, and are, only 
 mentioned here to show the intimate knowledge which chemists 
 possess of this agent. Indeed, so important were any investiga- 
 tions in madder considered, that the Societe Industrielle de 
 Mulhouse for several years offered 2000 francs as a premium 
 for the best analytical investigation of this substance. 
 
 Useful Products. — It will be observed in this brief outline 
 of the coloring matters of madder, that only three of them are 
 
340 
 
 MADDER. 
 
 of importance to the dyer, viz., the red, purple, and orange. It 
 will also be observed that these three coloring substances have 
 a similarity of action towards mordanted cottons. Taken singly, 
 not one of them forms a good dye ; but they constitute the 
 elements which together produce the richest and most perma- 
 nent reds which the modern dyer possesses. Indeed, prac- 
 tically, it is only necessary to consider madder as containing 
 no more than two coloring matters, as was formerly supposed ; 
 viz., the dun, or yellow, which constitutes the impurity of the 
 madder, and which the dyer endeavors to get rid of, and the 
 red-coloring matter. The former, or yellow, does not combine 
 with the cloth alone, and probably not at all; but it has a 
 strong affinity for the other coloring matters, and combines 
 with them when they are upon the cloth, and has to be sepa- 
 rated from them by after processes. The latter, or red, which 
 is a combination of all the three, the red, the purple, and the 
 orange, unites with the cotton as one, and is known to the dyer 
 only in the aggregate state. This coloring matter is difficultly 
 soluble in water, and therefore no strong decoction of it can 
 be obtained by boiling, so that it is not very applicable for 
 compound colors, and therefore of little avail in the fancy dye- 
 house. Many extensive fancy dyers, indeed, do not consider 
 madder as even belonging to their province. They use it very 
 seldom, except to give a peculiar tint to some light compound 
 colors, and for fast salmon colors, pinks, &c. When deep colors 
 are to be dyed by madder, the goods must be put into the dye- 
 bath or boiler along with the madder, in a way nearly similar 
 to that described for barwood. 
 
 Madder in the hands of the skilful operator can be made to 
 produce a vast variety of colors and tints, by corresponding 
 changes of his mordants, and the colors are all characterized 
 by a degree of permanency which no other vegetable dyew r ood 
 produces. The operations, however, are generally much more 
 tedious than those for ordinary fancy colors ; and much skill 
 is also required in preparing and applying the proper mordants 
 for madder colors, and also in the preparation of the cloths for 
 the different mordants. 
 
 Madder Preparations. — There are two coloring substances 
 prepared from madder, which are now being much used in dye- 
 ing and calico printing, and which seem to embrace all those 
 different coloring principles we have been describing ; these are 
 garancine and colorine. The former was first formed and de- 
 scribed by MM. Eobiquet and Colin, as far back as 1828 ; but 
 it was long before it was introduced generally to\he trade. 
 Garancine is a chocolate-colored powder having no taste or 
 smell ; but from differences in the modes of preparation, and 
 
MADDER PREPARATIONS. 
 
 341 
 
 also in the qualities of the madders from which it is prepared, 
 it varies very much in quality, which is probably the reason 
 why it has been repeatedly taken up and abandoned by dyers. 
 Ultimately, however, means of testing its quality, &c, were 
 devised, and have proved favorable to its more constant em- 
 ployment. The manner of forming garancine, as given by 
 MM. Eobiquet and Colin, is to take one part of madder, and 
 five or six parts of cold water, and allow the mixture to mace- 
 rate till the following day ; the whole is then thrown upon a 
 cloth-filter, and when drained is subjected to pressure. It is 
 then to be steeped again in cold water and pressed, and so on 
 for the third time. When these operations are completed, 
 almost half as much sulphuric acid (by weight) as there was 
 of the madder in its first state, is to be diluted with water, so 
 as to raise the temperature as much as possible, and this is 
 added to the pressed madder while hot, and stirred as rapidly 
 as possible ; the temperature is then raised and kept at 212° 
 for about an hour. A quantity of water is then added, and 
 the whole is thrown upon a filter ; water is poured over the 
 residue until it passes through the filter without taste of acid, 
 and the matter collected is then pressed and dried, and passed 
 through a sieve. This constitutes garancine. The sulphuric 
 acid used is not altered in character, but seems only to have 
 carbonized some of the impurities in the roots, without affect- 
 ing the red-coloring matter. There are several other methods 
 of preparing the substance, but not differing essentially from 
 that described; as throwing the rough madder into water, and 
 heating it to the boiling point, then adding the sulphuric acid, 
 after which the whole is filtered, washed, and dried, and reduced 
 to powder, &c. During the last few years the consumption, 
 and consequently the manufacture of garancine, has greatly in- 
 creased. The mode of testing garancine is similar to that 
 described for madders; either by the depth of dye produced 
 on mordanted cotton, or by means of the colorimeter. In 
 1843, a patent was taken for extracting garancine from the 
 waste madders of the dye-house, and we believe has been pro- 
 ductive of great saving and advantage. The substance of the 
 process thus patented is: — 
 
 "The invention consists in manufacturing a certain coloring 
 matter called garancine from refuse madder, or madder which 
 has been previously used in dyeing, such madder having 
 ordinarily been thrown away as spent and of no value, and the 
 said coloring matter called garancine having been produced 
 heretofore from fresh or unused madder. A large filter is 
 constructed outside the building in which the dye-vessels are 
 situated, formed by sinking a hole in the ground, and lining 
 
342 
 
 MADDER. 
 
 it at the bottom and sides with bricks without any mortar to 
 unite them. A quantity of stones or gravel is placed upon 
 the bricks, and over the stones or gravel common wrappering, 
 such as is used for sacks. Below the bricks is a drain to take 
 off the water which passes through the filter. In a tub adjoin- 
 ing the filter is kept a quantity of dilute sulphuric acid, of 
 about the specific gravity of one hundred and five, water being 
 one hundred. Hydrochloric acid will answer the several pur- 
 poses, but sulphuric acid is preferred as more economical. A 
 channel is made from the dye- vessels to the filter. The madder 
 which has been employed in dyeing is run from the dye-vessels 
 to the filter ; and while it is so running, such a portion of the 
 dilute sulphuric acid is run in and mixed with it as changes 
 the color of the solution and the undissolved madder to an 
 orange tint or hue. This acid precipitates the coloring matter 
 which is held in solution, and prevents the undissolved madder 
 from fermenting or otherwise decomposing. When the water 
 has drained from the madder through the filter, the residuum 
 is taken from off the filter and put into bags. The bags are 
 then placed in an hydraulic press to have as much water as 
 possible expressed from their contents. In order to break the 
 lumps which have been formed by compression, the madder or 
 residuum is passed through a sieve. To 5 cwt. of madder in 
 this state, placed in a wood or lead cistern, 1 cwt. of sulphuric 
 acid of commerce is sprinkled on the madder, through a lead 
 vessel similar in form to the ordinary watering-can used by 
 gardeners. An instrument like a garden spade or rake is next 
 used, to work the madder about so as to mix it intimately with 
 the acid. In this stage, the madder is placed upon a perforated 
 lead-plate, which is fixed about five or six inches above the 
 bottom of the vessel. Between this plate and the bottom of 
 the vessel is introduced a current of steam by a pipe, so 
 that it passes through the perforated plate and the madder 
 which is upon it. During this process, which occupies from 
 one to two hours, a substance is produced of a dark-brown 
 color approaching to black. This substance is garancine and 
 insoluble carbonized matter. When cool, it is placed upon a 
 filter and washed with clear cold water until the water passes 
 from it without an acid taste. It is then put into bags and 
 pressed with an hydraulic press. The substance is dried in a 
 stove and ground to a fine powder under ordinary madder- 
 stones, and afterwards passed through a sieve. In order to 
 neutralize any acid that may remain, from four to five pounds 
 of dry carbonate of soda for every hundred weight of this sub- 
 stance is added and intimately mixed. The garancine in this 
 state is ready for use." Sealed, August 8, 1843. 
 
COLORINE. 
 
 343 
 
 The following is the action of garancine when put into dif- 
 ferent qualities of water and with reagents: — 
 
 Distilled water, cold ... A pale yellow in about 24 hours. 
 Distilled water, boiling . . A pale reddish-yellow tint. 
 Spring water, cold .... Less colored than with cold distilled 
 
 water. 
 
 Boiling spring water . . Less colored than with boiling dis- 
 tilled water. 
 
 Cold lime-water .... Paler than with either cold distilled 
 
 or spring water. 
 Water with a little sul- ) Greenish-yellow tint after some 
 
 phuric acid ... J hours. 
 Water with H CI . . . . The same, but darker in tint. 
 Water with NO 5 .... Still darker tint, passing into a 
 
 brownish-blue. 
 Water with acetic acid . Faintly yellow. 
 Strong acetic acid .... Acquires a beautiful reddish-yellow 
 
 color. 
 
 f Becomes red immediately, and after 
 
 Cold alum water .... Chrome-red color. 
 Boiling alum water ... A dark-red color. 
 
 The mordants used for dyeing with garancine are the same 
 as for dyeing with madder. It only yields its color to the 
 mordanted cloth at a boiling temperature, and the water of the 
 bath or boiler does not become colored. A little sumach is 
 often used along with the garancine for reds. 
 
 If the water used in dyeing be a calcareous spring, a little 
 sulphuric acid, just enough to give the water a sour taste, 
 should be added; but when sumach is used, the acid is not re- 
 quired. The dye obtained by garancine is generally more 
 brilliant and lively than from madder. In printing, the color 
 is not so liable to run upon the white, and the goods are con- 
 sequently more easily cleared that when madder is used. 
 
 Colorine is the residue left by distilling the alcoholic tinc- 
 ture made by treating garancine with spirits of wine. It is 
 considered to be impure alizarine. When this product is taken 
 from the retort, it is in the form of an extract; but diluted 
 with water, separated, subjected to pressure, and then dried and 
 
 Water with ammonia 
 
 Ammonia 
 
 a few hours so deep as not to be 
 transparent. 
 Beautiful red color. 
 
 Dark red-brown. 
 
 Bright reddish color. 
 
344 
 
 MADDER. 
 
 pulverized, it resembles yellow ochre. It leaves a deep stain 
 on the fingers if moistened by it. It is prepared in France at 
 a cheap rate, and used in calico printing by being dissolved in 
 ammonia, thickened with gum, and applied to the cloth pre- 
 viously mordanted. 
 
 The mordants used for madder and the coloring preparations 
 obtained from it, are the acetate of alumina, acetate of iron, and 
 mixtures of these; the chlorides of tin, acetate of lead, and 
 acetate of copper, and sometimes ammoniuret of copper. The 
 last two are often used as alterants. In using iron mordants it 
 is of the utmost consequence that they be the proto-salts ; 
 hence, iron liquor is more frequently used than sulphate of 
 iron, which salt is more apt to become peroxidized. 
 
 In dyeing with madder, there are many operations not prac- 
 tised in the fancy dye-house, such as dunging, &c. 
 
 Coloring Principles of Madder. — The true composition 
 of the coloring substances contained in madder has been more 
 recently a subject of study by many chemists. Dr. Schunck 
 calls rubian the coloring principle of madder, which, under the 
 action of a special ferment named erythrozym, or of acids or 
 alkalies, would be converted into alizarine by losing water. 
 Thus:— 
 
 Rubian. Alizarine. 
 
 C i6 H 34 O 30 - 4 (C 14 H 5 0 4 ) + 14 HO. 
 
 The xanthine of Mr. Kuhlmann was the yellow coloring prin- 
 ciple of madder, which, under the influence of the atmosphere, 
 produced the various coloring substances extracted from this 
 root. 
 
 Mr. Decaisne, when examining under the microscope the cel- 
 lular tissue of madder, found that when the root was fresh, the 
 coloring matter contained in it was yellow, but turned red by 
 exposure to the air, and that old roots presented also the red 
 coloration. This experiment exhibits a coloring principle 
 which may be transformed into different colors by oxidation, 
 and by different chemical operations. 
 
 Mr. P. Schiitzenberger, working with the pure products, ob- 
 tained from madder by the process of Mr. E. Kopp, found the 
 following substances : — 
 
 2* Pu^urhie 1 Which are red, or orange red, and 
 
 o ur P^ rme? . ( dye red with alumina mordants. 
 
 3. Pseudo-purpunne. ) J 
 
 4. An orange substance, which dyes red with mordants of 
 alumina. 
 
 5. A yellow substance {Xanthopurpurine), distinct from xan- 
 thine, and which dyes yellow with mordants of alumina. 
 
COLORING PRINCIPLES OF MADDER. 845 
 
 Alizarine gives with alkalies a violet solution, and is nearly 
 insoluble in a boilinsr solution of alum. 
 
 o 
 
 Purpurine gives with alkalies a red solution, which does not 
 stand exposure to the atmosphere. It is also very soluble in an 
 alum solution, which becomes pink. 
 
 Some years ago, Mr. B. Kopp produced alizarine by sublima- 
 tion, by means of superheated steam passing through pulver- 
 ized madder. Another process by the same chemist, and 
 employed with advantage by Messrs. Shaaff and Lauth, of Stras- 
 bourg, consists in macerating madder for several hours in a 
 solution of sulphurous acid. After maceration, the liquors are 
 acidulated with sulphuric acid, and heated to about 100° or 
 110° Fahr., when purpurine precipitates. The liquors being 
 then made to boil for several hours, green alizarine is also 
 precipitated. The green coloring matter may be removed by 
 treatment with 15 to 20 times its weight of petroleum, and 12 
 per cent, of a solution of caustic soda (1 part soda for 12 of 
 water). After saturation by sulphuric acid, the yellow aliza- 
 rine is collected, and is ready for use for printing steam colors. 
 
 Green alizarine is as good as commercial alizarine, better than 
 the flowers of madder, and requires ten per cent, less mordant 
 than when the latter are employed. It should be wetted with 
 boiling water before using, otherwise it will swim on top of 
 the bath. Calcareous waters are to be avoided. 
 
 The purpurine is equal in coloring power to sixty times its own 
 weight of powdered madder, is soluble in ammonia, acetic acid, 
 alkaline carbonates, and even water. 
 
 When used for dyeing silk, it is well to neutralize it with 
 about 1 per cent, of chalk or carbonate of soda. The cotton 
 yarns are to be mordanted as usual, with the addition of a little 
 tannin. 
 
 For calico printing, the paste is made of f oz. purpurine in 
 one quart of water, and 20 per cent, of carbonate of soda. The 
 whole is boiled, filtered, and thickened. 
 
 For wool dyeing, the stuff is mordanted with alum and cream 
 pf tartar ; or tartar and. oxymuriate of tin prepared as follows : — 
 
 300 parts nitric acid ; 
 100 " water ; 
 
 50 " sal ammoniac ; and 
 
 50 " tin gradually added to the cold liquid. 
 
 This solution is allowed to rest several days, and is filtered 
 before it is ready for use. The mordanted wool is then dyed 
 in a solution of purpurine, beginning at a temperature of 86°, 
 and raising afterwards to the boiling point. 
 
 With cream of tartar and tin for mordants, the color is a scarlet 
 
346 
 
 MADDER. 
 
 red, nearly as fine as that from cochineal. Alum and cream of 
 tartar give a crimson red. For red orange, add to the above 
 mordants some fustic or Cuba wood, heat the whole in a tinned 
 kettle, and then dye with purpurine. 
 
 For silk printing, the stuff is mordanted with acetate of alu- 
 mina (5° B.), with a little chalk added to the water, dried, and 
 passed through a weak solution of gum tragacanth (| oz. per 
 quart). The printing paste is made with 1J oz. purpurine per 
 quart of water, and J oz. of soda crystals. After filtration add 
 J lb. roasted starch, heat the whole, and print with it when 
 cold. The cloth is then steamed, washed, passed through 
 soap, &c. 
 
 Purpurine does not give purples with iron mordants. 
 
 The madder left as residue, after the treatment by sulphu- 
 rous acid, may be transformed into garancine, but its dyeing 
 power is only one-half that of ordinary garancine. 
 
 Flowers of Madder. — This product, introduced into the trade by 
 Messrs. Julian and Roquer, consists of madder, which, by fermen- 
 tation, has been deprived of most of its mucilaginous and sac- 
 charine matters. The extra expense of this process is more 
 than paid by the alcohol resulting from the fermentation, and 
 the increased coloring power of madder flowers, which is double 
 that of common madder. 
 
 Commercial Alizarine or Pincoffineis due to Messrs. Schunck and 
 Pincoffs, of Manchester. It is a garancine, entirely free from 
 acid, and which has been submitted to high pressure or super- 
 heated steam. The substances which interfere with the purple 
 dyeing properties of alizarine are destroyed or modified by the 
 process. This commercial alizarine, gives a beautiful violet 
 with calcareous waters, and no raising is required. 
 
 Tests for Madder. — Madder is frequently adulterated with 
 foreign substances, which have been found to consist of: — 
 
 I. Brick-dust, sand, ochre, and clay ; 
 
 II. Saw dust from oakwood and mahogany, bran, and pow- 
 dered logwood, sapan, Brazil wood, &c. 
 
 The impurities of the first class are easily detected by the 
 calcination of a certain amount of the suspected powder. Pure 
 and well prepared madder does not contain more than 5 per cent, 
 of ashes. Some sorts, which have not been prepared very 
 carefully, may give 9 per cent, of ashes. But above this latter 
 proportion, all excess of ashes results from a fraudulent mix- 
 ture. The sample on trial ought to have been well desiccated 
 at 212° Fahr., because the proportion of water in madder is 
 also exceedingly variable. 
 
 The adulterations of the second class are not so easily detect- 
 ed. Mr. Pernod, of Avignon, has proposed the following rapid 
 
TESTS FOR MADDER. 
 
 347 
 
 process: A sheet of white paper, six inches square, is dipped 
 for one minute into a weak solution of bichloride of tin, put 
 afterwards upon a glass or porcelain slab, and covered by means 
 of a sieve with the madder on trial. After one-half hour, the 
 paper will show at the places touched by the foreign matters : — 
 
 Crimson-red points with Brazil wood ; 
 
 Purple spots with logwood ; 
 
 A yellow coloration with Lima or Cuba woods; while 
 Madder produces a very light yellow. 
 
 For discovering the tannin of oak and bark, another paper 
 is impregnated with an old solution of copperas, dried, and 
 then wetted with alcohol. If there are substances holding tannin, 
 the paper, after 15 minutes, shows blue-black spots, while mad- 
 der stains only a light-brown. 
 
 Good flowers of madder impart scarcely any coloration to 
 the distilled water in which they have been allowed to macerate. 
 The filtered water is neutral to the test papers, does not precipi- 
 tate by nitrate of baryta, becomes slightly pink-colored when 
 heated with oil of vitriol, and turns yellowish by hydrochloric 
 acid. 
 
 When the flowers of madder are of a bad quality, the water 
 is colored and acid, gives a precipitate by nitrate of baryta, 
 and becomes green after heating with sulphuric or muriatic 
 acids. 
 
 All these processes, while they permit the detection of fraudu- 
 lent impurities, do not indicate the coloring power of madder. 
 For this latter purpose, the only effective way consists in dyeing 
 several pieces of calico of the same size, mordanted with one 
 or several mordants, and comparing the result with that of a 
 madder of good quality. The operation is performed in glass 
 vessels heated over a water bath, the temperature of which is 
 slowly raised from 85° to 167° Fahr., during one hour and a 
 half, and then rapidly carried up to the boiling point, which is 
 kept on for 15 minutes. The calico samples, which have been 
 constantly stirred in order to dye them evenly, are rinsed in 
 ' cold water and dried. 
 
 The samples are then cut in two. One half is retained, and 
 the other is submitted to the following operations : A passage in 
 a solution of bleaching powder (J of 1 degree B.), at the tem- 
 perature of 95°, during five minutes; two washings, each 
 of 5 minutes, in weak soapsuds, heated at 100° and 120° ; 
 rinsing in clear water ; a raising in weak soapsuds with some 
 bichloride of tin ; and. lastly another passage in a soap bath, 
 whose temperature of 140° is raised to 212°. After washing, 
 rinsing, and drying, the samples are compared. 
 
 These numerous and somewhat tedious operations are neces- 
 
348 
 
 MUNJEET — ANNOTTA. 
 
 sary to obtain a true knowledge of the coloring power and 
 quality of the madder. Indeed, this substance will stand all 
 these operations, while the impurities will not. 
 
 Calcareous waters were thought to impart certain qualities to 
 the dyed products of certain localities ; on the other hand they 
 were accused of doing harm. Purpurine is not affected by 
 lime, while alizarine may be precipitated by it. These two 
 opinions are correct to a certain point, when we come to con- 
 sider the nature of the various kinds of madder, and products 
 of madder, used in the arts. The madders from Holland and 
 Alsace, grown in argillaceous soils, have generally an acid re- 
 action, which requires a certain quantity of base, lime, or soda, 
 to be neutralized. The madders from Avignon, on the con- 
 trary, are grown in calcareous soils, are perfectly neutral, and 
 an excess of lime would be rather prejudicial. The same rea- 
 soning will apply to certain commercial products of madder 
 which, like the garancine, often contain an excess of acid. In 
 such cases, calcareous waters are useful. 
 
 Munjeet 
 
 Has been tried as a substitute for madder. It contains more 
 coloring matter, and is found in commerce in bundles consist- 
 ing generally of thick and thin stalks; the thin-stalked variety 
 contains less coloring matter than the thick, and has the bark 
 on ; whereas the thick stalks are barked. The stalks of the 
 munjeet are very dry, light, and porous; the fracture exhibits 
 a congeries of empty tubes. The powdered munjeet is com- 
 posed of the thin and thick stalks mixed. 
 
 Eeds dyed with munjeet are very brilliant, but fugitive, being 
 destroyed by a short exposure to light and air. This vegetable 
 cannot, therefore, be a proper substitute for madder. 
 
 Annotta, or Arnotto. 
 
 This substance, the Roucou of the French dyers, is obtained 
 from a shrub originally a native of South America, and now 
 cultivated in Guiana, St. Domingo, and the East Indies. 1 It is 
 termed the annotta- tree, or bixa orellana, and seldom exceeds 
 twelve feet in height. The leaves are divided by fibres of a 
 reddish-brown color, and are four inches long, broad at the 
 base, and tending to a sharp point. The stem has likewise 
 fibres, which in Jamaica are converted into serviceable ropes. 
 
 u The tree produces oblong bristled pods, somewhat resem- 
 bling those of a chestnut. These are at first of a beautiful rose 
 
ANNOTTA, OR ARNOTTO. 
 
 349 
 
 color, but, as they ripen, change to a dark-brown, and bursting 
 open, display a splendid crimson or farina pulp, in which are 
 contained from thirty to forty seeds, somewhat resembling 
 raisin-stones. As soon as they arrive at maturity these pods 
 are gathered, divested of their husks, and bruised. Their pulpy 
 substance, which seems to be the only part which constitutes 
 the dye, is then put into a cistern, with just enough water to 
 cover it, and in this situation it remains for seven or eight days, 
 or until the liquor begins to ferment, which, however, may 
 require as many weeks, according to circumstances. It is then 
 strongly agitated with wooden paddles or beaters to promote 
 the separation of the pulp from the seeds. This operation is 
 continued until these have no longer any of the coloring matter 
 adhering to them; it is then passed through a sieve, and after- 
 wards boiled, the coloring matter being thrown to the surface 
 in the form of scum, or otherwise allowed to subside; in either 
 case, it is boiled in coppers till reduced to a paste, when it is 
 made up into cakes and dried."* 
 
 Another and more preferable mode of extracting the color- 
 ing matter from these seeds, is by rubbing them one against 
 another under water, so that the mucilaginous and other impure 
 matters contained in the interior of the seed are not mixed in 
 it. The coloring matter is allowed to settle, the water drawn 
 off, and the annotta left to dry. When prepared in this manner, 
 it has a fatty feel, is very homogeneous, and of a deep-red 
 color, which changes to dark-brown by drying. It has no 
 taste, but generally a disagreeable smell, when brought into 
 commerce. This smell, however, is not natural, but is owing 
 to stale urine having been added to it, in order to improve its 
 color, and keep it moist. 
 
 The Carribee Indians prepare the annotta, which they em- 
 ploy for painting their bodies, by smearing their hands with 
 oil, and then rubbing the seeds until the pulp is separated 
 under the form of a paste, which adheres to their fingers, and 
 which they remove with a knife and dry in the sun. 
 
 Annotta of good quality is of a lively red color when just 
 taken from the seeds, and before it has undergone any change. 
 It was found by Mr. John to contain the following ingre- 
 dients: — 
 
 * Annales de Chimie, tome 47. 
 
350 
 
 ANNOTTA, OR ARNOTTO. 
 
 Coloring and resinous matters . . . . 
 
 Vegetable gluten 
 
 Lignine 
 
 Extractive coloring matter 
 
 Matter resembling gluten and extractive . 
 Aromatic and acidulous matters . . . 
 
 28.0 
 26.5 
 20.0 
 20.0 
 4.0 
 1.5 
 
 100.0 
 
 Boiling water dissolves annotta, giving a thick decoction of 
 a yellow color. Alkalies form with it a white precipitate, giving 
 the liquor a clear orange color, which acids make redder. 
 
 Muriatic acid has no action upon annotta; chlorine destroys 
 its color. Nitric acid completely decomposes it, forming several 
 compounds, which have not yet been sufficiently examined. 
 Sulphuric acid poured upon solid annotta gives it a deep-blue 
 color, not unlike indigo, but it soon changes to a dark dirty- 
 green, and then to a darkish-purple. 
 
 The coloring matters of annotta are easily soluble in alka- 
 lies, and in this condition they are generally used in the dye- 
 house. The alkali used is either carbonate of soda or potash; 
 and when light shades upon silks and fine cottons are wanted, 
 soft soap is used. Sometimes a quantity of annotta is prepared 
 and kept as a stock liquor; but the practice is bad, as the 
 liquor soon becomes stale, and loses a great portion of its dye- 
 ing properties. It is best when newly prepared. A good 
 method of preparation is the following: Into a boiler, capable 
 of containing 10 to 12 gallons of water, are put 10 pounds' 
 weight of annotta, 2 lbs. of carbonate of soda, and 2 lbs. of 
 soft soap, and the mixture is boiled until the annotta is all dis- 
 solved. 
 
 Cloth put into this solution is dyed a dark orange ; but every 
 shade, from an orange to a cream color, can be dyed with it, 
 by merely using it in a proper state of dilution with water. 
 The cloth requires no previous preparation ; but for fine light 
 shades the color is improved by dissolving a little white soap 
 in the water used for diluting it. The goods are merely passed 
 through the solution, and dried from it; but where the color 
 is strong, the cloth must be washed in water containing a little 
 soap, to free it from the strong alkali in the coloring solution. 
 The addition of acids turns the color of cloths dyed by annotta 
 to a yellowish-red, so that by passing a piece of cloth dyed 
 orange through water, slightly acidulated, it assumes a scarlet 
 or salmon color, according to the quantity of coloring matter 
 used. But all the colors dyed by annotta are exceedingly fugi- 
 tive, and although neither acids nor alkalies can completely re- 
 move the colors dyed by it, still, they are constantly changing 
 
AXNOTTA, OR ARNOTTO. 
 
 851 
 
 and fading by exposure to the air and light. On this account 
 annotta is now very seldom used in the cotton dye-house, and 
 then it is used only as an auxiliary. It is, however, still used 
 for silks and woollens, as the objections to its use for cotton do 
 not apply so strongly in its relations to those substances. It 
 may also be used with propriety for mixed fabrics, such as 
 silk and cotton, silk and woollens, &c. 
 
 Annotta was considered to contain two distinct coloring mat- 
 ters, a yellow and red, till it was shown by M. Preisser that 
 the one is the oxide of the other, and that they may be obtained 
 by adding a salt of lead to a solution of annotta, which precipi- 
 tates the coloring matter. The lead is separated by sulphuret- 
 ed hydrogen; and the substance being filtered and evaporated, 
 the coloring matter is deposited in small crystals of a yellow- 
 white color. These crystals consist of bixine; they become yel- 
 low by exposure to the air, but by dissolving them in water 
 this change is prevented. 
 
 Sulphuric acid gives ... A yellow, which does not turn 
 
 When ammonia is added to bixine with free contact of air, 
 there is formed a fine deep-red color, like annotta, and a new 
 substance is produced, termed bixeine, which does not crystallize, 
 but may be obtained as a red powder ; this is colored blue by 
 sulphuric acid, and combines with alkalies, and is bixine with 
 addition of oxygen. When annotta, in the form of paste, is 
 mixed from time to time with stale urine for its improvement, 
 it is more than probable that this improvement consists in the 
 formation of bixeine from the bixine, by the ammonia of the 
 urine. This is rendered the more probable by finding the inte- 
 rior of the annotta yellow, while the red color is much more 
 developed upon the surface where the air has free access to it. 
 This naturally suggests the mixing of annotta with a little 
 ammonia, and exposing it to the air as much as possible pre- 
 vious to its being prepared for dyeing, as a much richer color 
 is thereby obtained. 
 
 The adulterations of annotta are oxide of lead and ochre. 
 These may be detected by burning a small quantity of it in a 
 china crucible; if pure, no residue will be left; but if oxide of 
 lead be the adulterant, by keeping the crucible at a red heat, a 
 small button of lead will be obtained ; and if ochre be present, 
 a red powder will be left. 
 
 The liquid sold in shops under the name of Scott's nankeen 
 dye, is a solution of annotta and potash in water. 
 
 Annotta is often used for coloring butter and cheese. 
 
 Nitric acid 
 Chromic acid 
 
 blue as it does with annotta. 
 A yellow shade. 
 A deep orange tint. 
 
352 
 
 ALKANET ROOT— AKCHIL. 
 
 Alkanet Root. 
 
 This is the root of a plant (Lithospermum tinctorium) which 
 grows in the Levant, and several other warm countries. It 
 was introduced as a dye a few years ago, but with little success. 
 The coloring matter is slightly soluble in water, but is rendered 
 soluble by alkalies, to which it gives a blue color, also by oils 
 and fatty substances, which it colors red. It has the following 
 reactions: — 
 
 Salts of lead Blue precipitates. 
 
 Salts of tin Crimson precipitates. 
 
 Salts of iron Violet-colored precipitates. 
 
 Salts of alumina Violet precipitates. 
 
 A variety of shades of lavender, lilac, violet, &c. are dyed by 
 this coloring matter, but caution and experience are necessary 
 to insure success, and the colors obtained are easily affected by 
 light, which, in our opinion, is the greatest barrier to its use. 
 Colors formerly were generally dyed with it by giving the 
 cloth an oil or soap preparation, the soap being combined with 
 alumina to serve as the base. 
 
 Akchil. 
 
 This coloring matter is prepared from lichens, a species of 
 sea-weed. The most/ esteemed is that denominated Lichen 
 roccella. The best sort comes from the Canary and Cape de 
 Verd Islands; but it is also found abundantly on the coasts of 
 Sweden, Scotland, Ireland, and Wales, and the people have 
 from time immemorial used it for dyeing cloths. The color- 
 ing matters prepared from these lichens have been long known 
 in commerce in the following forms: — 
 
 1st. As a pasty matter, called archil. 
 
 2d. A mass of a drier character, called persis ; and, 
 
 3d. As a red powder, called cudbear. 
 
 The details of the mode of preparing archil have been kept 
 a secret, and are but imperfectly known even yet. The fol- 
 lowing is what is known: The lichens are first ground between 
 two stones to a pulp, with the addition of water, and afterwards 
 put into a wooden trough, having a tightly-fitted cover; upon 
 the moist pulp is sprinkled a mixture of urine and ammonia, 
 and the vessels being then covered, fermentation soon begins. 
 The whole is occasionally stirred, and more ammonia and urine 
 are added from time to time. After a few days, the color be- 
 
ARCHIL. 
 
 353 
 
 gins to develop itself, but about six weeks are required to 
 complete the operation. The whole is then removed from the 
 trough and placed in casks, and may be kept for years. The 
 keeping is considered to improve the intensity of the color, 
 which should be of a deep reddish-violet. 
 
 Acids change the color to . Bright red, and 
 
 Alkalies to A blue. 
 
 Sea-salt gives it .... A crimson tint. 
 
 Sal ammoniac A ruby-red tint. 
 
 Alum throws down ... A brownish-red precipitate. 
 
 Salts of tin Bed precipitates. 
 
 Salts of iron Eed-brown precipitates. 
 
 Salts of copper Cherry-brown precipitates. 
 
 There are no mordants required for dyeing with archil. It 
 is not used for cotton dyeing, but extensively for silk and 
 woollens, imparting very beautiful tints, which, however, are 
 not permanent. It is often used as a bottom color for reds 
 which are to be dyed by safflower, cochineal, &c, and gives 
 depth and a beautiful rich tint to the colors so dyed. 
 
 The coloring principle of these lichens, and especially that 
 producing the archil, has been the subject of extensive inves- 
 tigation with some of the first chemists both in this and other 
 countries. The results of these researches are, that the color- 
 ing matter of these lichens depends upon the oxidation of a 
 colorless base, or compound existing in the plant. That of 
 archil is termed orcine, and the oxidized color is known as 
 orceine. Dr. Stenhouse has given very simple methods of ob- 
 taining these matters from the lichens. Could this color be 
 obtained of a permanent character, and fixed upon cotton, its 
 value would be inestimable. 
 
 The process of Mr. Stenhouse consists in picking and wash- 
 ing the impurities from the lichens, which are afterwards ground 
 in a mill to a liquid paste. By successive washings of this 
 paste, the ligneous bodies remain on the filter, and a liquor is 
 obtained, into which is poured some bichloride of tin, which 
 precipitates all the coloring matter. 
 
 The latter is well washed, put into vats with a certain pro- 
 portion of ammonia, and frequently stirred for a few days ; the 
 purple coloration gradually appears, and the maximum is 
 obtained after one month of such treatment. It is sold in 
 paste, or in the dried state. 
 
 Archil improves by being kept for two years; at the third 
 year it begins to deteriorate. It raises considerably the shade 
 of indigo. 
 
 In 1857, Mr. Marnas, of Lyons, discovered a process to make 
 26 
 
354 
 
 ARCHIL. 
 
 with archil a color remarkable alike for its beauty and fastness ; 
 it is the French purple. It is produced in the following man- 
 ner : — 
 
 Powdered lichens are macerated with a milk of lime, in order 
 to render soluble the coloring matter, which combines with the 
 lime. After filtration, hydrochloric acid is added, which satu- 
 rates the lime, and causes the coloring substance to separate 
 in a gelatinous state, which is washed and dissolved in hot am- 
 monia. The solution is very slow, as it requires 20 to 25 
 days, and a temperature of about 153° Fahr. The ammoniacal 
 liquid, which has become violet, is then precipitated by chloride 
 of calcium ; a purple lake is thus produced, which is the French 
 purple. 
 
 An aluminous lake may be obtained by au aluminous rea- 
 gent. . This last preparation is considered preferable for print- 
 ing. 
 
355 
 
 PROPOSED NEW VEGETABLE DYES. 
 
 There are occasionally papers, of great value to the dyer, 
 appearing in periodicals and the reports of scientific societies, 
 that are not seen by practical men, and their value to a great 
 extent is consequently lost. We have selected a few in proof 
 of this statement, and trust it will stimulate to a more active 
 research after such articles, which cannot fail to be productive 
 of good results. 
 
 SOORANJEE. 
 
 This substance was investigated lately by Professor Ander- 
 son, from whose paper we give the following account: — 
 
 " The subject of these experiments was imported into Glas- 
 gow, some time since, under the name of Sooranjee, with the 
 intention of introducing it as a substitute for madder in the 
 art of dyeing. For this purpose it was, on its arrival, sub- 
 mitted for trial to some of the most experienced and skilful 
 calico printers in Glasgow, all of whom concurred in declaring 
 it not to be a dye at all, and to be totally destitute of useful 
 applications. My friend, Professor Balfour, happening to hear 
 of this circumstance, was so good as to obtain for me a quantity 
 of the root, which has enabled me to submit it to a chemical 
 investigation. 
 
 " Sooranjee is the root of the plant, and is imported cut up 
 into pieces from one to four inches in length, and varying in 
 diameter from a half down to nearly an eighth of an inch. On 
 the small pieces the bark is thick, and forms a large propor- 
 tion of the whole root, but on the larger fragments it is much 
 thinner. Its external color is pale grayish-brown ; but when 
 broken across, it presents colors varying from fine yellow to 
 brownish-red, and confined principally to the bark. The wood 
 itself has only a slight yellowish shade, deepest in the centre, 
 and scarcely apparent close to the bark ; but it is colored dark- 
 red by alkalies, indicating the presence of a certain quantity 
 of coloring matter in it. The bark is readily detached and 
 its inner surface, as well as that of the wood, has a peculiar 
 silvery appearance, most apparent on the large pieces and al- 
 most entirely absent in the smaller. Boiled with water, it gives 
 a wine-yellow decoction, and with alcohol a deep-red tincture. 
 
356 
 
 SOORANJEE. 
 
 "Solution of morindine gives with subacetate of lead a pre- 
 cipitate, depositing itself in crimson flocks, which is extremely 
 unstable, and cannot be washed without losing coloring matter. 
 With solutions of baryta, strontia, and lime, it gives bulky-red 
 precipitates sparingly soluble in water. Perchloride of iron 
 produces a dark-brown color, but no precipitate. When its 
 ammoniacal solution is added to that of alum, the alumina pre- 
 cipitated carries down with it the morindine as a reddish-lake, 
 and when added to perchloride of iron, a brown precipitate is 
 thrown down, which cannot be distinguished from pure per- 
 oxide of iron, but which contains morindine, as the supernatant 
 fluid is colorless. 
 
 "The formula thus ascertained brings out an interesting re- 
 lation between morindine and the coloring matters of madder, 
 and more especially that one which is obtained by the sublima- 
 tion of madder purple. From his analysis of this substance, 
 Schiel* deduces the formula C 7 H 4 0 4 . As this, however, is 
 no more than the simplest expression of the analytical results, 
 and as all the other madder-coloring matters examined con- 
 tained 28 equivs. of carbon, we are justified in supposing its 
 real constitution to be represented by quadruple of that for- 
 mula, or C 28 Hj 6 0 16 , which differs from that of morindine by 
 a single equivalent of water only. The unsublimed madder- 
 purple is also connected, though more remotely, with morindine, 
 and differs only by containing 5 equivs. of hydrogen less, its 
 formula according to Schiel being C 28 H 10 0 15 . 
 
 "This similarity, however, does not extend itself to their 
 properties as dyes, in which respect they differ in a very re- 
 markable manner. I have already mentioned that the calico- 
 printers had entirely failed in producing a color by means of 
 sooranjee, and this I have fully confirmed as regards the com- 
 mon mordants. I digested morindine, for a long time, in a 
 gradually increasing heat, with small pieces of cloth mordanted 
 with alumina and iron; but nothing attached itself; and the 
 mordants, after boiling for a minute or two with soap, were 
 found to be unchanged. Even with the root itself alum mor- 
 dant only acquired a slight reddish-gray shade, and iron became 
 scarcely appreciably darker in color. The case was different, 
 however, when cloth mordanted for Turkey red was employed. 
 I obtained from Glasgow pieces of calico prepared for Turkey- 
 red both by the old and new processes; and I found that both 
 acquired with morindine, in the course of a couple of hours, 
 or even less, a dark brownish-red color, devoid of beauty, but 
 perfectly fixed. These observations agree with the account 
 
 * Chemical Gazette, vol. v. p. 77. 
 
SOORANJEE. 
 
 357 
 
 given by Mr. Hunter, of the method of dyeing with the M. 
 citrifolia employed by the Hindoos. The cloth is first soaked 
 in an imperfect soap, made by mixing the oil of the Sesamum 
 orientate with soda-lye. After rinsing and drying, it is treated 
 with an infusion of myrobalans (the astringent fruit of the 
 Terminalia chebula), and exposed for four or five days in the sun. 
 Ifr is then steeped in solution of alum, squeezed, and again 
 exposed for four or five days. On the other hand, the powdered 
 roots of the Morinda are well rubbed with oil of sesamum, and 
 mixed with the flowers of the Lythrum fruticosum (Roxburgh), 
 or a corresponding quantity of purwas (the nut-gall of a species 
 of Mimosa). The whole is introduced along with the cotton 
 into a large quantity of water, and kept over a gentle fire for 
 three hours, when the temperature is brought to the boiling 
 point. The red color so obtained is, according to Mr. Hunter, 
 more prized for its durability than its beauty. This is simply 
 a rude process of Turkey-red dyeing. He also mentions, that 
 by means of an iron mordant, a lasting purple or chocolate is 
 obtained; but, in this case, the color is probably affected by 
 the tannin of the astringent matters employed in the process. 
 
 Ct Morindine is a true coloring matter, and is capable of at- 
 taching itself to common mordants. It gives, with alumina, a 
 deep rose-red, and with iron, violet and black; but the colors 
 are not very stable, and it has a strong tendency to attach itself 
 to the unmordanted parts of the cloth, and to degrade the white. 
 Morindine, after treatment with sulphuric acid, is capable of 
 attaching itself to ordinary mordants. 
 
 " The discovery of a peculiar coloring matter, capable of fix- 
 ing itself exclusively on Turkey-red mordant, is of interest, as 
 establishing the existence of a peculiar class of dyes hitherto 
 totally unsuspected — a class which maybe extensive, and may 
 yield important substances. It may serve also, in some respects 
 to clear up the rationale of the process of Turkey-red dyeing, 
 which has long been a sort of opprobrium on chemistry. 
 Although that process has been practised for a century in 
 Europe, and has undergone a variety of improvements, no clear 
 explanation of it was for a long time given ; but it was sup- 
 posed that by the action of the dung, of which large quantities 
 are employed, the cloth underwent a species of animalization, 
 as it was called, bj which it acquired the property of receiving 
 a finer and more brilliant color than could be attached to it by 
 purely mineral mordants. Eecent experiments have, however, 
 shown that the oil, which is largely employed in the process, 
 undergoes decomposition by long exposure to the air in con- 
 tact with decomposing animal matter, and is converted into a 
 sort of resinous matter, which constitutes the real mordant for 
 
358 
 
 CARAJURU, OR CHICA. 
 
 Turkey-red. This has been pretty clearly made out by the 
 experiments of Weissgerber * He found that when cloth had 
 been treated with oil, so as to give when dyed a fine rose-red 
 color, he could, by digestion with acetone, extract from it the 
 altered oil ; and, as it was removed, the cloth gradually lost 
 the power of attracting the coloring matter of madder, until, 
 when it was entirely separated, the cloth passed through tbe 
 dye without acquiring any color. On the other hand, he found 
 that, by applying the substance extracted by acetone in suffi- 
 cient quantity to cloth, he could obtain the richest and deepest 
 colors with madder, without the addition of any other sub- 
 stance whatsoever. These observations receive additional con- 
 firmation from the experiments detailed in the present paper, 
 as it must be sufficiently obvious that the dark-red color 
 obtained on Turkey-red mordant, with morindine, must be 
 entirely irrespective of the alumina, on which that substance is 
 incapable of fixing. 
 
 " I fully agree with the opinion expressed by Persoz, that 
 the use of alum mordant, which is at present always employed 
 in Turkey-red dyeing, will be entirely abandoned as soon as 
 calico printers have learned the method of modifying at will 
 the oil which they employ, so as to bring it at once into the 
 state in which it acts as a mordant. Some steps have been 
 made in this direction by making use of some chemical agents, 
 as nitric acid and chloride of lime, for the purpose of acting on 
 the oil; but the improvements which have been effected stop 
 far short of what I believe will eventually be effected when the 
 system of pure empiricism, which has been all along employed 
 in this particular process of dyeing, is abandoned, and the sub- 
 ject submitted to really scientific investigation. It is under- 
 stood that M. Chevreul has entered upon the inquiry, and in 
 his hands there is little doubt but that it will meet with a 
 satisfactory solution." — From the Transactions of the Royal 
 Society of Edinburgh. 
 
 Carajuru, or Chica 
 
 Is a vegetable substance known by these names, and is 
 obtained from America, where it is used by the natives as a 
 dye. The following short extracts from a paper by J. J. Virey , 
 will show its character and properties: — 
 
 u M. de Humboldt has described in the Annales de Ghimie et 
 de Physique (vol. xxvii. p. 315), under the name of Chica, a 
 vegetable product of a brick-red color, obtained by macerating 
 
 * Persoz, sur Tlmpression des Tissus, vol. iii. p. 176. 
 
WONGSHY. 
 
 359 
 
 in water the leaves of Bignonia chica, a shrub of the family of 
 the Bignoniacece from equinoctial America. 
 
 " As we have obtained from Para in Brazil, under the de- 
 nomination Crajuru, or Carajuru, a substance not only analo- 
 gous in its physical and chemical characters to the Chica, but 
 of a red-brown violet tint much more beautiful and rich, and 
 like vermilion, while the other appeared duller and much 
 inferior, it may be useful to give fresh details about this pro- 
 duct, which has been imported to be tried in dyeing. 
 
 "The Crajuru, or Carajuru (Carucuru, according to others), 
 is a kind of powder, or fecula, in pieces somewhat light, inodor- 
 ous, insipid or slightly bitter, not soluble in water, but soluble 
 in alcohol, ether, and the oils and fats, without being com- 
 pletely resinous, burning with a flame, but leaving a quantity 
 of gray cinders. It is wholly dissolved by alkalies, and acids 
 precipitate it without greatly altering its color, if they are not 
 concentrated. 
 
 "The Crajuru now brought into Europe must furnish a 
 rather strong and beautiful dye, the brilliancy of which appears 
 quite superior to that of Orleans."* 
 
 WONGSHY 
 
 Ts another vegetable substance. An investigation of its 
 properties was made by W. Stein, from whose paper we ex- 
 tract the following account: — 
 
 u Towards the end of last year, a new material for dyeing 
 yellow, called wongsky, was exported on experiment from 
 Batavfa to Hamburg, for a sample of which I am indebted to 
 the kindness of M. Vollsack, merchant. Whether it has 
 hitherto been applied as a dyeing material, and with what 
 results, could not be ascertained. The following notice, there- 
 fore, will probably not be without interest : — 
 
 "The new dyeing material consists of the seed-vessels of a 
 plant, which, according to the information from M. Reichen- 
 bach, belongs to the family of the Gentianeaa. The form of 
 the unilocular capsules is longish-ovate, drawn out to a point 
 next the end of the peduncle, and crowned upon the opposite 
 
 * " The drink called chica, which is so much used among the people of 
 South America, must not be confounded with the subject of the present 
 notice. This drink, in fact, is prepared with pods of algaroba, (Mimosa 
 algaroba), which are nearly as sweet as the carouba of the Ceratonia Siliqua, 
 and with the bitter stalks of the Schinus molle. It said that old women are 
 employed to chew these Algarobce and the Schinus, and then to spit them 
 into a vessel ; water is added ; the whole soon ferments, and affords a kind 
 of intoxicating beer." 
 
360 
 
 WONGSHY. 
 
 and more obtuse one with the dried six-lobed calyx. They 
 vary in size; but on an average their length is 1.5 to 2 inches, 
 and the diameter at the thickest part 0.5 ; the color is not uni- 
 formly reddish-yellow, but at some places darker, at others 
 lighter. The surface is more or less irregularly waved with 
 six to eight longitudinal ribs. The odor resembles saffron, and 
 subsequently honey. The shell is pretty hard and brittle, but 
 becomes quickly mucilaginous when chewed, imparting a yel- 
 low color to the saliva, with a slightly bitter taste; it swells 
 up considerably in water. Inside the capsules there are a 
 number of dark reddish-yellow seeds (in one specimen I 
 counted 108); they are not attached to the sides, but are im- 
 bedded in a hardened pulp, and so connected one with the 
 other. These seeds are tolerably hard, soften but slowly when 
 chewed, have no particular taste, but after some time produce 
 at the point of the tongue a slight but peculiar sourish-sweet 
 pungency, resembling the action of Paraguay rue. The pulp, 
 on the other hand, cementing them together, has a strong bit- 
 ter taste, which is particularly perceptible at the back part of 
 the palate. 
 
 "The wongshy, especially when pounded, readily gives up 
 to water, both at the usual temperature as well as on boiling, 
 a coloring principle, which possesses such an enormous divisi- 
 bility that two parts of the pounded capsules furnish 128 parts 
 of a liquid, which placed in a cylindrical vessel of white glass 
 with a diameter of three inches still appears of a bright wine- 
 yellow color. The concentrated extract is very mucilaginous, 
 and has a fiery-red color, which, on large dilution, passes into 
 a golden-yellow, the red disappearing. % 
 
 " Protochloride of tin produces no change at the ordinary 
 temperature, or after a long time; on boiling, a dark orange- 
 colored precipitate results. 
 
 "Acetate of lead produces no change. 
 
 " Basic acetate of lead causes a turbidness at the ordinary 
 temperature, and an orange-colored precipitate on boiling. 
 
 "Protosulphate of iron changes the color into a dark brown- 
 ish-yellow, without, however, a precipitate resulting either in 
 the cold or on ebullition. 
 
 "Alum, acetate of alumina, and acetate of zinc, produce 
 yellow precipitates only on boiling. 
 
 "Barytic water causes a yellow precipitate at the ordinary 
 temperature, which on boiling acquires a reddish tint. 
 
 "Lime-water gave a pure yellow precipitate; solutions of 
 gypsum and chloride of calcium are not precipitated by it even 
 on boiling; well water, with a considerable amount of carbon- 
 ate of lime, does not precipitate the coloring principle even 
 
WONGSHY. 
 
 361 
 
 with the assistance of heat; it is, consequently, not able to 
 decompose the combinations of lime with acids. 
 
 "To ascertain the value of the wongshy coloring matter for 
 the purposes of dyeing, 1 part of the pounded capsules was 
 digested for twelve hours with 20 parts of lukewarm water, 
 being frequently stirred, and the liquid then strained. The 
 coloring matter is most quickly extracted in this manner with- 
 out its becoming gelatinous from the formation of paste, as 
 would happen were the liquid boiled. Properly prepared 
 samples of woollen cloth, some without any mordant, others 
 mordanted with alum, protochloride of tin, acetate of alumina, 
 and basic acetate of lead, were dyed with this extract at a 
 temperature of about 104° Fah. ; the color does not turn out 
 so pure at a higher temperature. The unmordanted cloth was 
 dyed a beautiful and uniform orange color by one immersion ; 
 of the mordanted samples, those with alum and acetate of 
 alumina were better than those with protochloride of tin ; the 
 least satisfactory was that in which basic acetate of lead had 
 been used as mordant. The tone of the color was not altered 
 by the first three mordants, but it was less intense, and the 
 stuffs were not uniformly penetrated by the coloring matter. 
 However, the samples with alum mordant gave perfectly satis- 
 factory results after a second immersion. The coloring matter 
 likewise combines readily and uniformly with silk, communi- 
 cating to it a very glowing golden color, so that in this case I 
 also prefer not having recourse to mordants. Cotton, as was 
 to be expected, can only be dyed with the assistance of mor- 
 dants, and the best results appeared to be obtained with tin 
 mordants ; the color was orange, of a very agreeable tint. 
 
 "The color, both upon wool, silk, and cotton, resists soap 
 perfectly ; but alkalies give it a yellow, acids and tin salt, a red 
 tint. By this behavior it differs from the color of annotta, with 
 which, as will subsequently be seen, it possesses in other 
 respects great resemblance, a resemblance which unfortunately 
 exists as regards the action of light. When exposed to light, 
 the color very soon fades upon cotton, less quickly upon wool; 
 and in this case it is more permanent upon the unmordanted 
 samples. It resists the light longest upon silk; and, in this 
 respect, when compared with the other known yellow colors, 
 may be reckoned among the best. 
 
 U I obtained a beautiful yellow, with a faint tint of red, by 
 mordanting the woollen cloth with lime water, and immersion 
 in the boiling vat ; it resists the soap perfectly, and the action 
 of light much better than the orange. It is altered in a similar 
 manner to the orange by alkalies, acids, and tin salt, only less. 
 Several very beautiful shades of yellow may be obtained by 
 
862 
 
 WOXGSHY. 
 
 adding pearlash or caustic potash to the dye, and immersing 
 the unmordanted fabric at the ordinary temperature. The 
 union of the color with the fibre takes place very quickly and 
 very uniformly. By the addition of 1 part pearlash to 30 
 parts dye liquor, a yellow was obtained with a remarkable 
 glow from a slight admixture of red. By the addition of twice 
 the quantity of pearlash, a lively yellow, with a faint tint of 
 green, was obtained. A still larger amount of pearlash cannot 
 be used, as it renders the color dull and impure. With caustic 
 potash, instead of pearlash, I obtained, in the first place, a pure 
 brilliant yellow, with less red than with the pearlash ; in the 
 latter case, a beautiful Canary-yellow with a shade of green. 
 Ammonia acts in the same manner, but the color, under all 
 circumstances, contains more red. The color also appears of a 
 somewhat different shade when the fabrics are first immersed 
 in the dye liquor, and then, after being washed, placed in an 
 alkaline bath. 
 
 "In the case of silk and cotton, the effect of alkalies is similar, 
 but less apparent, because the silk and cotton fibres imbibe less 
 of the coloring substance than those of wool. 
 
 "That this color resists the soap is self-evident, but it also 
 suffers less from the action of light than the orange ; and when 
 fabrics so dyed are passed through a vinegar or muriatic acid 
 bath, a brilliant aurora color is obtained. This interesting 
 behavior, which the wongshy coloring matter has in common 
 with that of annotta, is explained by the chemical character of 
 the former, which is a weak acid ; it combines with the alkalies 
 and with the alkaline earths, as evident by the precipitation 
 with baryta and lime-water. Its combinations with the former 
 possess a pure yellow color, and are decomposed by stronger 
 acids, when the liberated coloring matter separates of a brilliant 
 vermilion color. But the coloring matter thus separated is no 
 longer the same as that which was originally contained in the 
 aqueous solution, for it is now perfectly insoluble in water, and 
 is only dissolved in small quantity, and of a golden-yellow 
 color, by absolute alcohol, ether, and spirit of 0.863 spec. grav. 
 In the moist state, it has a vermilion color; when dry and in 
 the purest state it is brown-red, like Eatanhia extract, and is 
 easily reduced to powder ; but if it still contains sugar and fat, 
 it has a beautiful yellowish-red color, in thick layers, whilst in 
 thin layers it is yellow and transparent, and becomes moist in 
 the air. On heating the pure substance upon platinum, at first, 
 yellow vapor is given off, and at some spots the color becomes 
 pure yellow; it subsequently turns black, fuses, and chars. 
 The residual cinder is difficult to burn ; the yellow vapors con- 
 dense, when the experiment is made in a glass tube, into yellow 
 
ALOES. / • 
 
 oily drops. Concentrated sulphuric acid renders it scarcely 
 perceptibly blue, and the acid acquires the same color, which 
 quickly passes into violet and brownish-red, whilst the coloring 
 matter slowly dissolves. Water separates from this solution a 
 dirty yellowish-gray flocculent substance. 
 
 "The reaction of the wongshy coloring matter which has 
 just been mentioned, has no resemblance with the reaction of 
 sulphuric acid upon annotta, for the liquid never acquires a 
 pure blue color, as is the case with annotta, but is violet from 
 the first, and only for a minute. 
 
 "It dissolves readily in caustic ammonia and caustic soda, 
 with a golden yellow color." 
 
 Aloes. 
 
 Dr. Bancroft, in his work on the Philosophy of Permanent 
 Colors, recommended this substance as a dyeing agent. He 
 proposed to digest it in nitric acid, by which means he obtained 
 aloetic acid, a substance capable of being used as a dye. This 
 matter has been the subject of extensive investigation by many 
 chemists, and has been occasionally more or less used as a dye- 
 ing agent. A patent, however, has recently been taken out 
 for certain applications of aloes to dyeing. The following is 
 the proposed method of preparation: — 
 
 "The mode of preparing the coloring matter from aloes is 
 as follows : Into a boiler or vessel, capable of holding about 
 100 gallons, the patentee puts 10 gallons of water, and 132 lbs. 
 of aloes, and heats the same until the aloes is dissolved; he 
 then adds 80 lbs. of nitric or nitrous acid, in small portions at 
 a time, to prevent the disengagement of such a quantity of 
 nitrous gas as would throw part of the contents out of the 
 boiler. When the whole of the acid has been introduced, and 
 the disengagement of gas has ceased, 10 lbs. of liquid caustic 
 soda, or potash of commerce, of about 80° are added, to neutral- 
 ize any undecomposed acid remaining in the mixture, and to 
 facilitate the use of the mixture in dyeing and printing. If 
 the coloring matter is required to be in a dry state, the mixture 
 may be incorporated with 100 lbs. of China clay, and dried in 
 stoves, or by means of a current of air. In preparing the 
 coloring matter from extract of logwood, the materials are used 
 in the manner and proportions above described; the only dif- 
 ference being, that the extract of logwood is substituted for the 
 aloes. 
 
 "The coloring matter is used in dyeing by dissolving a suffi- 
 cient quantity in water, according to the shade required, and 
 
364 
 
 PITTACAL — BARBARY ROOT. 
 
 adding as much hydrochloric acid or tartar of commerce as will 
 neutralize the alkali contained in the mixture, and leave the 
 dye-bath slightly acidulated. The article to be dyed is intro- 
 duced into the bath, which is kept boiling until the desired 
 shade is obtained. 
 
 "When the coloring matter is to be used in printing, a suffi- 
 cient quantity is to be dissolved in water, according to the shade 
 required to be produced; this solution is to be thickened with 
 gum, or other common thickening agent; and hydrochloric 
 acid, or tartar of commerce, or any other suitable supersalt is 
 to be added thereto, for the purpose before mentioned. After 
 the fabrics have been printed with the coloring matter, they 
 should be subjected to the ordinary process of steaming, to fix 
 the color."— Sealed, Jan. 27, 1847. 
 
 Pittacal. 
 
 This substance is obtained from beech tar. It is dry and 
 hard, very brittle, and resembles indigo in appearance. It has 
 no taste or smell, and does not dissolve in water. Sulphuric 
 acid dissolves it, producing a violet-colored solution. Muriatic 
 acid gives a red-purple solution, from which alkalies precipi- 
 tate the pittacal. Acetate of lead, salts of tin, sulphate of cop- 
 per, acetate of alumina, all give deep-blue precipitates, not 
 readily changed. This color is easily fixed upon cotton by tin 
 and alumina.* It is sometimes used for blueing linens. 
 
 Barbary Eoot. 
 
 The plant from which this is obtained grows in almost every 
 part of the world; great quantities of it are obtained from India, 
 where it grows in great abundance and perfection. The color- 
 ing matter is found in the whole of the root. In the stem it is 
 found around the pith and near the bark. This coloring sub- 
 stance is much used in dyeing or staining leather; but it is not 
 much used in the dyeing of cotton. Mr. Edward Solly has 
 made some investigations of this root. See Journal of the 
 Royal Asiatic Society, 
 
 * Records of General Science. 
 
365 
 
 ANIMAL MATTERS 
 
 USED IN DYEING. 
 
 The coloring substances of this chapter, belonging to the 
 animal kingdom, are but few in number, and are used especi- 
 ally for dyeing animal fibres. They are employed to a certain 
 extent for calico printing. 
 
 Cochineal. 
 
 This is a small insect called the coccus cacti, and is much 
 sought after for its tinctorial qualities. It furnishes the finest 
 known shades of crimson, red, purple, scarlet, &c, for woollens 
 and silk. The insects are reared in great abundance in Mexi- 
 co. They feed upon a cactus plant, which the natives cultivate 
 around their dwellings for that purpose. The insects attach 
 themselves to the leaves of the plant, and increase rapidly in 
 number. The females live about two months, and the males 
 only about one month. The season of rearing and gathering 
 lasts about seven months,; during this period the insects are 
 gathered three times. After each gathering, some of the branches 
 and leaves containing females and their young are preserved 
 under shelter, and on the return of the proper season they are 
 distributed over the plantation. A few females are put into a 
 small nest made of some downy substance, and the young in- 
 sects quickly spread themselves out upon the leaves, to which 
 they attach themselves. They are gathered by brushing them 
 off the leaves with the feather end of a quill into boiling hot 
 water, in which they are kept a few seconds. This not only 
 kills them instantly, but causes them to swell to twice their 
 natural size. When taken out the hot water, they are spread 
 out and dried, and then packed for the market. Some culti- 
 vators instead of hot water use steam, and others again place 
 them in an oven or upon a hot plate. The difference in the 
 appearance of the cochineal is caused by these different modes 
 of killing the insects and heating them. They shrivel in dry- 
 ing, and assume the appearance of irregular formed grains, 
 fluted and concave. The best sorts seem as if dusted with a 
 
366 
 
 COCHINEAL. 
 
 4. Saline matters, as 
 
 white powder, and are of a slate-gray color ; but these appear- 
 ances are often imparted by means of powdered talc, to deceive 
 the purchaser. 
 
 There are several kinds of cochineal in commerce. The finest 
 is known by the name of mistic, from the name of the place in 
 which the insects are reared, La Mistica, in the province of 
 Honduras. Another is called wild, because they are collected 
 from plants growing in a state of nature; but this variety is 
 inferior to the former. The third is a mixture of these two, or 
 rather the debris or fragments, and varies in quality according 
 to the proportion of the mixture. 
 
 Cochineal has been the subject of several chemical investi- 
 gations, the results of which are not very satisfactory. The 
 following are instances of these. The cochineal contains: — 
 
 1. Carmine, which may be termed the coloring matter. 
 
 2. A peculiar animal matter. 
 
 A fatty matter, composed ( gi^e^and 
 
 ( Volatile fatty acids. 
 Phosphate of lime. 
 Carbonate of lime. 
 Chloride of potassium. 
 Phosphate of potash. 
 Combination of potash with 
 organic acids. 
 
 Mr. John gives the following as the result of his analysis : — 
 
 Ked-coloring matter 50.0 
 
 Gelatin 10.5 
 
 Wax 10.0 
 
 Debris of skin, &c 14.0 
 
 Gummy matter 13.0 
 
 Phosphate of lime, of potash, and iron, and chloride ) 
 of potassium f 
 
 Carmine, or the coloring matter of cochineal, may be obtained 
 by macerating finely ground cochineal with ether, which dis- 
 solves out the fatty matter, and then dissolving the carmine by 
 the application of hot alcohol, and leaving the solution to cool; 
 by evaporating, the carmine is deposited as a beautiful red 
 crystalline substance, which dissolves freely in water. It is 
 affected by the following reagents as under: — 
 
 Tannin « Gives no precipitate. 
 
 Most acids Change its color from a bright 
 
 to a yellowish-red. 
 Boracic acid Does not change the color, but 
 
 rather reddens it more. 
 
TESTS FOR COCHINEAL. 
 
 367 
 
 Potash, soda and ammonia . Change it to a crimson-violet. 
 Baryta and strontia . . . Produce the same effect. 
 
 Lime Gives a crimson- violet precipi- 
 tate. 
 
 Alumina Combines with it and precipi- 
 tates it as a beautiful red ; 
 but if boiled, it passes to violet- 
 red. 
 
 A little potash, soda, or am- 
 monia added prevents this 
 change, and preserves the 
 stability of the red. 
 Protoxides of tin . . . . Change it to crimson-violet. 
 
 Peroxide of tin .... Changes it to yellowish-red. 
 Salts of iron Turn it brown ; no precipi- 
 tate. 
 
 Salts of lead Change it to violet; no precipi- 
 tate. 
 
 Salts of copper Change it to violet; no precipi- 
 tate. 
 
 Nitrate of mercury . . . Gives a scarlet-red precipitate. 
 Nitrate of silver .... Has no action upon it. 
 Chlorine Turns it yellow. 
 
 " As may be supposed, the result of all these contrary opinions 
 is, that it is perfectly impossible to judge of the goodness of a 
 cochineal by its physical character. In order to ascertain its 
 value, we must have recourse to comparative experiments. We 
 are indebted to MM. Eobiquet and Anthon for two methods of 
 determining the quality of cochineals, according to the quan- 
 tity of carmine they contain. The process of M. Eobiquet 
 consists in decolorizing equal volumes of decoction of different 
 cochineals by chlorine. By using a graduated tube, the quality 
 of the cochineal is judged of by the quantity of chlorine em- 
 ployed for decolorizing the decoction. The process of M. An- 
 thon is founded on the property which the hydrate of alumina 
 possesses of precipitating the carmine from the decoction so as 
 to decolorize it entirely. The first process, which is very good 
 in the hands of a skilful chemist, does not appear to us to be 
 a convenient method for the consumer: in the first place, it is 
 difficult to procure perfectly identical solutions; in the next 
 place, it is impossible to keep them a long time without altera- 
 tion. We know that chlorine dissolved in water reacts, even 
 in diffused light, on this liquid, decomposes it, appropriates its 
 elements, and gives rise to some compounds which possess an 
 action quite different from that of the chlorine solution in its 
 
368 
 
 COCHINEAL. 
 
 primitive state. The second process seems to us to be prefera- 
 ble, as the proof liquor may be kept a long while without 
 alteration. A graduated tube is also used ; each division repre- 
 sents one-hundredth of the coloring matter. Thus, the quan- 
 tity of proof liquor added exactly represents the quantity in 
 hundredths of coloring matter contained in the decoction of 
 cochineal which has been submitted to examination. 
 Another process is: — 
 
 "The coloring matter of cochineal being soluble in water, 
 I have used this solvent for exhausting the different kinds 
 which I have submitted to examination in the colorimeter. I 
 operated in the following manner : I took a grain of each of 
 the cochineals to be tried, dried at 122° Fah. ; I submitted 
 them five consecutive times to the action of 200 grains of dis- 
 tilled water at water-bath heat, each time for an hour ; for every 
 200 grains of distilled water I added two drops of a concen- 
 trated solution of acid sulphate of alumina and of potash. This 
 addition is necessary to obtain the decoctions of the different 
 cochineals exactly of the same tint, in order to be able to com- 
 pare the intensity of the tints in the colorimeter.* 
 
 u In order to estimate a cochineal in the colorimeter, two 
 solutions obtained, as described above, are taken ; some of these 
 solutions are introduced into the colorimetric tubes as far as 
 zero of the scale, which is equivalent to 100 parts of the supe- 
 rior scale; these tubes are placed in the box, and the tint of 
 the liquids inclosed is compared by looking at the two tubes 
 through the eye-hole, the box being placed so that the light 
 falls exactly on the extremity where the tubes are. If a differ- 
 ence of tint is observed between the two liquors, w T ater is added 
 to the darkest (which is always that of the cochineal taken as 
 type) until the tubes appear of the same tint.f The number 
 of parts of liquor which are contained in the tube to which 
 water has been added is then read off; this number, compared 
 with the volume of the liquor contained in the other tube, a 
 volume which has not been changed, and is equal to 100, indi- 
 cates the relation between the coloring power and the relative 
 quality of the two cochineals. And if, for example, 60 parts 
 of water must be added to the liquor of good cochineal, to 
 bring it to the same tint as the other, the relation of volume of 
 
 * Care must be taken not to add to the water, which serves to extract the 
 coloring matter from the different cochineals, more than the requisite quantity 
 of acid sulphate of alumina and solution of potash, because a stronger dose 
 would precipitate a part of the coloring matter in the state of lake. 
 
 | For diluting the liquors, the same water must always be used which has 
 served to extract the coloring matter of the cochineals under examination, 
 otherwise the darkest decoction would pass into violet as water was added to 
 it to bring back the tint to the same degree of intensity as that of the decoc- 
 tion to which it is compared. 
 
COCHINEAL. 
 
 369 
 
 the liquids contained in the tubes will be in this case as 160 is 
 to 100, and the relative quality of the cochineals will be repre- 
 sented by the same relation, since the quality of the samples 
 tried is in proportion to their coloring power." 
 
 Another adulteration of cochineal consists in taking part of 
 the coloring substance by a rapid ebullition in water, then 
 steeping the insects into a concentrated logwood or peachwood 
 liquor, drying, and covering them with ground chalk or talc. 
 
 This adulteration is detected by means of lime-water, which 
 completely precipitates the coloring matter of cochineal, and 
 leaves the solution clear. If logwood or peachwood be pre- 
 sent, the solution remains purplish red after the addition of 
 lime-water. 
 
 Alumina mordants produce with cochineal solutions, crimson 
 colors which are very fine and fast; tin mordants give a 
 scarlet color, remarkable for its beauty and fastness. Pink is 
 obtained with an alumina mordant, but the cochineal is boiled 
 with ammonia and water, instead of water alone. The affinity 
 of cochineal is greater for wool than for silk. 
 
 Some of the German chemists, supposing that the plant upon 
 which the insect feeds might be the source of the coloring mat- 
 ter, instituted a series of experiments to determine that point, 
 but without success. The conclusions they came to were, that 
 the animal economy plays a prominent part in the formation of 
 the coloring matter. 
 
 Carmine is manufactured extensively in France, and is used 
 for superior red inks, paints, and for coloring artificial flowers. 
 It is prepared on a large scale by boiling a quantity of cochi- 
 neal in water with soda, and then adding to it a little alum, 
 cream of tartar, and the white of eggs, or isinglass — which 
 separates the carmine as a fine flaky precipitate. This precipi- 
 tate is carefully collected. 
 
 There is something in the production of good carmine which 
 is not yet fully understood. It has not yet been prepared in 
 this country in the same perfection as in France (page 80). It 
 is found also, that, with a coal fire, a smaller quantity of it is 
 produced than when a wood fire is employed; and there are 
 many other little points which show the delicacy of its pre- 
 paration. 
 
 The residue of the carmine, and some portions of the pre- 
 cipitate from the cochineal, when first taken from the fire, are 
 collected and boiled in water; to this mixture is added a solu- 
 tion of alum and chloride of tin, by which a beautiful red- 
 colored precipitate or lake is formed. This constitutes the 
 beautiful pigment known as carmine lake. 
 24 
 
370 
 
 LAKE LAKE, OR LAC. 
 
 Lake Lake, or Lac, 
 
 Ts a concrete juice which exudes from several kinds of plants. 
 It appears, however, to be determined that it is caused by an 
 insect named coccus jicus, or ccecus loco, and may therefore be 
 regarded as of animal origin. There are several varieties of 
 this product under the names of stick-lac, seed-lac, and shell-lac. 
 There are also brought from India two other products dis- 
 tinguished as lac-lac and lac-dye — which are the kinds mostly 
 used in dyeing, but their composition is not very well known. 
 They however contain a goodly quantity of resinous matter, 
 which must be destroyed before they are put to use as a dye. 
 Lac-lac is obtained fit to use as a dye by boiling the gum-lac 
 with alkaline water, which dissolves the coloring matter along 
 with some of the resinous. To this is added some alum, which 
 precipitates the whole as an aluminous product, in which state 
 it is used. 
 
 Dr. Bancroft discovered that acids destroyed the resinous 
 matter of lac dye, and rendered the coloring matter soluble, 
 and this is the mode generally adopted in working with this 
 substance. 
 
 The following may be taken as the ordinary means of pro- 
 ducing this color: Add to four pounds of lac dye three 
 pounds of strong sulphuric acid, and set the mixture aside for 
 two days; pour over it half a gallon of boiling water ; stir the 
 whole well, and leave it to settle for twenty-four hours , the 
 clear liquor is then to be decanted into a leaden vessel, and 
 the residue washed with water until all the coloring matter is 
 dissolved. The washings may be added to the liquor in the 
 leaden vessel. There is then added to this liquor a quantity 
 of lime-water, until the solution barely tastes acid, which pre- 
 cipitates the sulphuric acid ; the whole is then thrown upon a 
 filter, and the clear liquor passing through the filter forms the 
 dye. 
 
 Some dyers take about 32 parts of lac dye, and rub it down 
 fine in 10 parts of strong sulphuric acid; then add three times 
 the quantity of the mixture of water, and set aside for two 
 days ; it is then ready for use, requiring merely to be diluted 
 as required. 
 
 The French dyers generally take 32 parts of lac dye, rubbed 
 down in 12 parts of hydrochloric acid of 30° Twaddell ; when 
 well mixed, it is diluted with about an equal quantity of water, 
 set aside for twenty-four hours, and stirred from time to time ; 
 it is then ready for use. Many dyers treat the lac-lac in the 
 same way as the lac dye, using one pound of sulphuric acid 
 
KERMS — MUREXIDE. 
 
 371 
 
 to two pounds of lac-lac ; in other respects the process is the 
 same. 
 
 The mordants employed for dyeing with the lacs are termed 
 lac spirits ; the lac and spirits are mixed previous to using. 
 Lacs are employed as substitutes for cochineal, and most of 
 the colors obtained by the one are producible by the other ; 
 but for fine reds the lac is much inferior. This dye is only 
 used for silk and woollens. 
 
 This is also an animal substance — the dried bodies of another 
 species of the coccus insect. This insect is supposed to have 
 been known as a dye so early as the time of Moses ; it was 
 used in India at a very early age, and was highly valued both 
 by the Eomans and Spaniards for dyeing purples, but after the 
 cochineal dye was discovered, the latter was used in preference, 
 on account of the superior beauty of the colors. Accordingly, in 
 many countries where the kerms insect was reared and enriched 
 the people, the remembrance of it is lost. 
 
 Good kerms is of a full deep-red color, having a pleasant 
 smell, and sharp sour taste; the red-coloring matter is soluble 
 in wates and in alcohol. It possesses properties similar to 
 cochineal. 
 
 Acids render it Yellowish-brown. 
 
 Alkalies Crimson-violet. 
 
 Iron salts turn it Black. 
 
 Alum renders it Blood-red. 
 
 Salts of tin A bright red. 
 
 For a red with tin it requires about 12 times the quantity of 
 kerms as of cochineal, and the color is a little inferior. As a 
 dye, it is not much used, and only for silk or woollens. There 
 is but little affinity between cotton and the coloring matters of 
 cochineal, lacs, and kerms. 
 
 Kerms, or Kermes. 
 
 Gray-color. 
 
 . Olive-green. 
 
 . Cinnamon-brown, 
 
 Sulphate of copper and tartar . 
 Tin salts and tartar . . . . 
 
 MUREXIDE. 
 
 This fine color, which is considered as a purpurate of am- 
 monia, had a great success, as long as aniline colors were not 
 
372 
 
 MUREXIDE. 
 
 known ; the greater cheapness of the latter caused murexide to 
 fall into oblivion. 
 
 Murexide is extracted from uric acid, after the transformation 
 of the latter into alloxane; and the operation requires a great 
 deal of care and precision. 
 
 The uric acid, which is cheaply obtained from Peruvian 
 guano, is gradually thrown into nitric acid, taking care to pre- 
 vent a too great elevation of temperature ; the mixture is then 
 allowed to cool. After 24 hours the alloxane crystallizes, and 
 after separation from the excess of acid, is made to crystallize 
 a second time in water. The formula of anhydrous alloxane 
 is C 8 H 4 N 2 O 10 . A solution of alloxane reddens litmus, imparts 
 a purple-red color to wool, and colors copperas an indigo blue. 
 
 Carbonate of ammonia is then added drop by drop to a boiling 
 solution of alloxane, until the liquor has a slight smell of am- 
 monia. Carbonic acid is evolved, and soon after there is a 
 deposit of crystals of murexide = C 12 H 6 N 5 O g . This substance 
 is very slightly soluble in water, although it colors it a deep 
 red; it is also insoluble in alcohol and ether. Alkaline solu- 
 tions dissolve it, and are colored blue; but the murexide is 
 soon decomposed if heat is applied. Its aqueous solution gives 
 with 
 
 Nitrate of soda — red precipitate, ^ 
 
 Nitrate of potassa — brown- red precipitate, ! Both solutions 
 
 Chloride of calcium — red, turning purple, f being boiling. 
 
 precipitate, J 
 Chloride of barium — dark-red precipitate ; 
 Zinc salts — gold-yellow precipitate ; 
 Bismuth — orange precipitate; 
 Bichloride of mercury — purple-red precipitate; 
 
 Fabrics mordanted with mercury or lead salts, and plunged 
 into tepid solutions of murexide, become dyed a fine purple-red, 
 which may be changed to violet by soap or alkalies. With zinc 
 mordants, yellow and orange shades are obtained. These colors 
 are beautiful, but without fastness. 
 
 no precipitate. 
 
373 
 
 COLORS DERIVED FROM COAL TAR. 
 
 The last ten years have been fruitful in the discovery and 
 the application to dyeing and calico printing, of a great many 
 new dyes derived from coal tar, and known under the cognomen 
 of Aniline Colors. 
 
 Production of Coal Tar. — The distillation of bituminous 
 coals in closed vessels gives rise to a variety of products, which 
 may be classified as follows : — 
 
 I. Gaseous substances, forming what we know under the 
 name of illuminating gas, and which is a mixture of bicarburet 
 and protocarburet of hydrogen, carbonic oxide and acid, sul- 
 phureted hydrogen and hydro-sulphide of ammonium. These 
 latter impurities are more or less removed by water, lime, and 
 copperas, in the process of purifying illuminating gas. 
 
 II. Water, holding in solution ammonia and its carbonate, 
 hydrosulphide and sulpho-cyanide of ammonium ; and from 
 which most of the ammoniacal salts used in the arts are 
 extracted. 
 
 III. Coal tar, which is a black, thick, and ill-smelling sub- 
 stance, generally heavier than water, and from which all the 
 colors which form the subject of this chapter are extracted 
 after various chemical transformations. 
 
 IV. Coke, or nearly pure carbon, which is left as a residue 
 in the retort or furnace, and the specific gravity of which is 
 variable with the quality of bituminous coal employed, and the 
 process of carbonization. 
 
 Composition of Coal Tar.— The carbonization of many or- 
 ganic matters, such as wood, peat, shales, &c, also produces tar ; 
 but these kinds of tar are poor in color-giving substances, and, 
 at the present time, coal tar from bituminous coals is the only 
 source from which the aniline dyes are extracted. Coal tar 
 is also variable in its composition ; the temperature at which 
 the carbonization has been effected has a great influence on 
 the products. Indeed, coal carbonized at a low temperature 
 may give a tar lighter than water, but which will contain less 
 benzole and naphthaline than the same coal carbonized at a high 
 temperature. 
 
 Taking as a standard the coal tar produced in the gas works, 
 we find it a very complex body, formed of a great many sub- 
 stances having acid, neutral, and alkaline properties, among 
 
874 
 
 COLORS DERIVED FROM COAL TAR. 
 
 which we will notice those employed for our subject, color- 
 making. 
 
 Boiling 
 
 Names. Formulae. Specific gravities. points (Fahr.). 
 
 Acids of coal tar : — 
 
 Carbolic or Phenic, C 12 H 6 0 2 1065 370 
 
 Cresylic, C 14 H 8 0 2 397 
 
 Kosolic, C 24 H l2 0 6 
 
 Neutral substances of coal tar : — 
 
 o 
 
 Benzole or Benzine, 
 
 C 12 H 6 
 
 850 
 
 177 
 
 Toluole, 
 Xylole, 
 
 C U H 8 
 
 C 16 H 10 
 
 870 
 
 230 
 
 867 
 
 164 
 
 Cumole, 
 
 C isH 12 
 
 870 
 
 299 
 
 Cymole, 
 
 861 
 
 341 
 
 Naphthaline, 
 
 C 20 H 8 
 
 1153 
 
 428 
 
 Alkaloids of coal 
 
 tar: — 
 
 
 
 Picoline, C 12 H 7 N 961 271 
 
 Aniline, C 12 H 7 N ' 1080 360 
 
 Toluidine, C 14 H 9 N 388 
 
 Xylidine, C 16 H U N 418 
 
 Cumidine, C 18 H 13 N 952 437 
 
 Cymidine, C 20 H 15 N 482 
 
 Chinoline, C 18 H 7 N 1081 462 
 
 The acid substances can be removed by caustic solutions of 
 soda or potassa, and the alkaloids or basic substances by di- 
 luted muriatic or sulphuric acids. The neutral bodies are sepa- 
 rated by fractional distillations. 
 
 Among all these substances, the most useful for the manu- 
 facture of dyes, are carbolic acid, benzole, toluole and naphtha- 
 line ; the others are found mixed with them in greater or less 
 quantity, and their action is comparatively little known. 
 
 We see also that aniline, toluidine, &c., are already formed 
 in the coal tar ; but their percentage is so small that it has been 
 found more advantageous to manufacture them directly from 
 the benzole and toluole, which are found comparatively in large 
 proportion, and are extracted by the following processes : — 
 
 Distillation of Coal Tar. — The tar is first distilled in 
 iron boilers, and the distillate is separated into two portions, 
 one lighter, and the other heavier than water, and known under 
 the name of light oil, and heavy or dead oil. ' What remains in 
 the still, is a pitch, which is soft or brittle, according to the 
 amount of dead oil distilled over, and which is used for water- 
 proof cements, rough varnishes, the covering of roofs, &c. Cer- 
 tain kinds of oils, called green oils, on account of their color, 
 
ANILINE. 
 
 375 
 
 pass at the end of the distillation, at about 700° Fahr., and are 
 used for the manufacture of carriage grease. 
 
 The dead oils are rich in naphthaline, and when newly pre- 
 pared, or separated from the solid naphthaline, are used mostly 
 for the preservation of timber, railroad ties, &c, under the not 
 very appropriate name of creosote. The solid naphthaline may 
 be purified by expelling by pressure the liquid hydro-carbons 
 which contaminate it, and subliming it with the addition of 
 some sand and lime, which retain the last impurities. Purified 
 naphthaline is in the form of white and pearly scales, and is 
 submitted to various operations for its transformation into 
 several dyes. 
 
 The light oils contain the benzole, toluole, and part of the 
 carbolic acid of the coal tar, mixed with other oils and impu- 
 rities, which it is necessary to remove by several fractional dis- 
 tillations by means of steam or fire. By the first operation, light 
 oils are separated into crude naphtha, which contains the ben- 
 zole, toluole, &c, and into other oils rich in carbolic acid. 
 The crude naphtha is then purified by treatment with oil of 
 vitriol and soda, which precipitate and dissolve the tarry mat- 
 ters, and are afterwards distilled by steam, in order to separate 
 the benzole and the toluole. What remains is the solvent 
 naphtha, used for making varnishes and dissolving India rubber. 
 
 The oils containing carbolic acid may be distilled over again, 
 collecting what passes between 300° to 400° Fahr. By shaking 
 it with a caustic solution of soda (1.08 sp. gr.), carbolic acid 
 will be dissolved, forming carbolate of soda, and the neutral 
 oils will float at the surface, and will be removed. The solution 
 of carbolate of soda is then neutralized by sulphuric or muri- 
 atic acid, forming sulphate, or muriate of soda (Na CI), and 
 the separated carbolic acid is purified by oil of vitriol and ano- 
 ther distillation. Carbolic acid is a powerful antiseptic, and is 
 used for the manufacture of several dyes. 
 
 We have briefly seen how benzole, toluole, carbolic acid, and 
 naphthaline, which are the most important elements of coal tar 
 colors, are obtained. We shall pass now to the production of 
 aniline. 
 
 Aniline. — This alkaloid extracted first from indigo, ^till 
 bears a name derived from anil, the Portuguese name of in- 
 digo. Some years ago, it was thought that pure benzole alone 
 would produce the best aniline ; but impure benzoles having 
 given better results in the manufacture of aniline dyes, it has 
 been ascertained that a certain proportion of toluole in com- 
 mercial benzoles or benzines was advantageous, and those con- 
 sidered as such contain from one-fourth to one-third of toluole. 
 We shall therefore consider under the name of aniline a mix- 
 ture of aniline and toluidine. 
 
376 
 
 ANILINE. 
 
 The first step in the manufacture of aniline, consists in trans- 
 forming the mixture of benzole and toluole into nitro-benzole 
 and nitro-toluole, by the action of fuming nitric acid or a 
 mixture of nitric and sulphuric acids. The proper proportion 
 of acid is put into a stoneware or cast-iron vessel, which can be 
 cooled off at will, and the hydro-carbons are run slowly into 
 it, stirring occasionally. The reaction may be represented by 
 the following formulas: — 
 
 Benzole. Nitric acid. Nitro-benzole. 
 
 C 12 H 6 + HN0 6 = C 12 H 5 N0 4 + 2H0 
 
 Toluole. Nitric acid. Nitro-toluole. 
 
 "CJ3? + HN0 6 - C^ 4 H 7 N0 4 + 2HO 
 where one equivalent of hydrogen of the hydro-carbon unites 
 with one of the oxygen of the nitric acid, and the remaining 
 peroxide of nitrogen combines with the hydro-carbon. It is 
 what is called a transformation by oxidation. 
 
 The nitro-benzole and nitro-toluole produced are separated 
 from the acid by a large quantity of water, washed thoroughly 
 with a diluted solution of carbonate of soda, and form the 
 commercial nitro-benzine or nitro-benzole. 
 
 It is heavier than water, yellow, has the odor of bitter al- 
 monds, and is soluble in alcohol and ether. 
 
 The other operation consists in reducing or deoxidizing the 
 nitro-benzine or nitro-toluidine, that is to say, by replacing 
 their oxygen by a certain amount of hydrogen, as may be seen 
 by these chemical figures : — 
 
 Nitro-benzole. Aniline. 
 
 C 12 H 4 N0 4 + 6H = C 12 H 7 N + 4HO 
 
 Nitro-toluole. Toluidine. 
 
 C 14 H 7 N0 4 + 6H = C 14 H 9 N + 4HO 
 
 This reduction can be effected by several processes ; for in- 
 stance, by sulphide of ammonium, and by nascent hydrogen. 
 But; iron turnings and strong acetic acid, as devised by Mr. 
 Bechamp, have been found the most advantageous in practice. 
 The reaction may be expressed thus: — 
 
 Nitro-benzole. Aniline. 
 
 c7 2 H 5 NO^ + 4Fe + 2HO = C^H.N + 2(Fe 2 0 3 ) 
 
 Nitro-toluole. Toluidine. 
 
 c7 4 H 7 N0 4 + 4Fe + 2HO = C^N" + 2(Fe 2 0 3 ) 
 
THEORY OF ANILINE COLORS. 
 
 377 
 
 One part of commercial nitro-benzole is mixed with one part 
 of strong acetic acid, to which is added 1^ part of iron turnings. 
 The operation is made in an iron cylinder, furnished with a 
 stirring apparatus, and a condenser. When the transforma- 
 tion is complete, heat is applied, and the whole is distilled, ex- 
 cept the peroxide of iron which remains in the retort. The 
 crude aniline is treated with a little soda or lime, and distilled 
 over again. 
 
 The aniline thus produced is a mobile oil, colorless when 
 pure, and difficult to freeze. Its specific gravity is 1.020, and 
 it boils at 360° Fahr. It emits vapors at the ordinary tem- 
 perature of the atmosphere, and burns with a large smoky 
 flame. Slightly soluble in water, its true solvents are alcohol, 
 ether, &c. It forms salts with acids. 
 
 Much of what we have said about aniline may be applied to 
 toluidine. 
 
 Aniline is also considered as an amide of the organic radical 
 phenyl, as may be seen by this equation : — 
 
 Aniline. Phenyl amide. 
 
 c^n = cwiy* 
 
 Theory of Aniline Colors. — Although the remarkable 
 researches of MM. *A. W. Hofmann, Grirard, and de Laire, &c, 
 have shed much light on the composition of aniline colors, we 
 cannot say that there is at the present day a true theory of 
 these colors, that is to say, a theory which answers entirely all 
 cases, and explains satisfactorily all the transformations. 
 
 Three opinions are now held : 1st, aniline or toluidine alone 
 cannot produce colors, while their mixture will ; 2d, aniline or 
 toluidine will each of them give colors; 3d, toluidine alone is 
 the source of the colors, but requires the presence of aniline 
 for their production. 
 
 All the aniline colors appear to be due to various degrees of 
 oxidation of this alkaloid, when submitted to oxidizing agents. 
 For instance, a solution of hypochlorite of lime (bleaching 
 powder) gives it a bluish-purple color. Bichromate of potassa 
 or peroxide of manganese, &c, and some sulphuric acid, pro- 
 duce in a solution of sulphate of aniline, green, blue and black 
 colors. Nascent oxygen, as produced by the galvanic decom- 
 position of water, will also act on aniline. For this experiment, 
 the aniline is dissolved in water acidulated with a little sulphuric 
 acid, and at the platinum pole, where oxygen is evolved, will 
 be seen a green coloration, which will turn blue, violet, and 
 finally red, showing the influence of more or less oxidation. 
 
 The processes employed, as well in experimental researches, 
 
378 
 
 THEORY OF ANILINE COLORS. 
 
 as in the manufactures, for the production of aniline or coal 
 tar colors, are all based on methods of oxidation, reduction, and 
 substitution, of the organic substances under treatment. 
 
 We have already seen examples of oxidation, where the sub- 
 stance acted upon is made to gain a certain amount of oxygen, 
 or more generally to lose part of its hydrogen ; and of reduc- 
 tion, in the transformation of nitro-benzole and nitro-toluole 
 into aniline and toluidine. 
 
 The methods of substitution consist in replacing certain or- 
 ganic groups by other groups called organic radicals, such as 
 phenyl, methyl, &c. 
 
 A great many substances occasion transformations by oxi- 
 dation and reduction. The following are employed in the 
 manufacture of coal tar colors. 
 
 I. Oxidizing agents : — 
 Oxygen, air, ozone ; 
 
 Nitric acid, nitrous oxides, nitrates ; 
 
 Chlorine, bleaching powders or liquids, chlorates ; 
 
 Bromine, iodine ; 
 
 Cyanoferride of potassium (red prussiate) ; 
 
 Arsenic acid, arseniates ; 
 
 Ammonia, with oxygen or air ; 
 
 Chromic acid, bichromates with sulphuric acid ; 
 
 Permanganic acid, permanganates; 
 
 Peroxides of manganese, lead, antimony, &c. ; 
 
 Sulphide of copper, &c. &c. ; 
 which give up part of their oxygen, or attract this gas, or cause 
 its production. 
 
 II. Eeducing agents : — 
 
 Nascent hydrogen, sulphureted hydrogen ; 
 Sulphurous acid, sulphites and hyposulphites; 
 Cyanides, sulpho-cyanides ; 
 Salts of protoxide of iron ; 
 
 tin ; 
 
 Aldehyd, &c. &c. ; 
 which have a great attraction for oxygen, or fix a certain 
 amount of carbon or hydrogen on organic molecules. 
 
 We shall see further on, that by varying the proportion of 
 these reagents, the length of the operation, and the tempera- 
 ture, various shades, or if we may say so, various degrees of 
 oxidation or reduction, may be obtained. 
 
 By their transformation into colors, the alkaloids we have 
 examined, aniline, toluidine, &c, form different bases, which 
 have been examined by MM. A. W. Hofmann, Girard,de Laire, 
 and Chapoteaut, and whose composition and hypothetical mode 
 of formation are as follows : — 
 
THEORY OF ANILINE COLORS. 
 
 379 
 
 Violaniline. Aniline. 
 
 c" 36 H 15 N^= 3(C 12 H 7 N)-6H 
 
 Mauvaniline. Aniline. Toluidine. 
 
 C 3S H 17 N^ = 2(C I2 H 7 N) + CJH^-6H 
 
 Rosaniline. Aniline. Toluidine. 
 
 'cj^N, - C^N + 2(C^iXn)-6H 
 
 Chrysotoluidine. Toluidine. 
 
 G^PJH, - 3(O^N)-6H 
 
 These bases unite with acids, and form well crystallized salts 
 which have a great tmctorial power. 
 
 Under the influence of reducing agents, such as nascent 
 hydrogen, the base rosaniline dissolved in muriatic or sulphuric 
 acid, in which some zinc is added, is transformed into 
 
 Leucaniline, Rosaniline. 
 
 C 40 H 21 N 3 = C 40 H 19 N 3 + 2H 
 
 which is colorless itself, and gives colorless salts. Exposure to 
 the air will, by means of oxidation, restore the original colored 
 salt of rosaniline. Leucaniline is soluble in alcohol, and 
 scarcely in cold water. 
 
 Another base extracted from the waste product of rosaniline 
 is chrysaniline = 0 40 H 17 N 3 , and is freely soluble in water, when 
 combined with hydrochloric acid. 
 
 The aniline blues and violets present examples of substitu- 
 tion, where three atoms of typic hydrogen are replaced by the 
 organic radicals, phenyl, methyl, ethyl, &c. 
 
 For instance, aniline blue is a triphenylic rosaniline — 
 
 — C! i ^" l6 1 1ST • 
 
 - 0 « }3(C 12 H 4 ) r»' 
 
 Aniline violet (blue shade) is a diphenylic rosaniline — 
 
 = c « {2(0%}^; 
 
 And aniline violet (red shade) is a monophenylic rosaniline — 
 
 Until now, we have examined substances which accord with 
 the rules of our theory ; but the base, mauveine, discovered by 
 Mr. W. H. Perkin, has a composition quite different, as may be 
 
880 
 
 ANILINE REDS. 
 
 seen by its formula — C 54 H 24 N 4 , and which does not agree with 
 the above rules. This base, which has been obtained perfectly- 
 pure in the crystallized state, is different from all aniline bases 
 by forming a salt with carbonic acid. 
 
 Aniline Eeds. — We begin with these dyes, because they 
 are the salts of rosaniline, from which we derive most aniline 
 colors. We cannot help seeing a certain analogy in the pro- 
 cesses of manufacture of these colors and those of the compounds 
 of carbon and iron. To make steel we partially decarburize 
 pig-metal, or carburize iron to a certain point ; here, in many 
 cases, we also partially deoxidize rosaniline, or oxidize aniline 
 to a certain point. We mix pig-metal with iron in order to 
 produce a certain steel, we also mix rosaniline salts with aniline 
 to make a certain color. Pig-iron is the most carburized iron; 
 rosaniline is the most oxidized aniline. 
 
 Aniline red, under the name of fuchsine, or magenta, was ob- 
 tained first, on a practical scale, by heating together aniline and 
 anhydrous bichloride of tin ; a hydrochlorate of rosaniline is 
 thus formed. Sulphate of aniline and binoxide of lead, nitrate 
 of peroxide of mercury and aniline were also used ; but, at the 
 present day, aniline is peroxidized or dehydrogenated by means 
 of arsenic acid. Into a cast-iron vessel, which can be heated 
 on a paraffin bath, is poured a mixture of 20 parts by weight 
 of syrupy arsenic acid, containing 76 per cent, of the solid 
 acid, and 12 parts of commercial aniline. An arseniate of 
 aniline is formed, w r hich, by an elevation of temperature is 
 transformed into rosaniline and arsenious acid. During the 
 whole operation the mass is constantly stirred. The molten mass 
 is then mixed with some water, run into a boiler, boiled with 
 steam to remove the impurities, and filtered. By adding lime 
 to the solution, rosaniline is precipitated with the insoluble ar- 
 senite of lime produced, and may be dissolved in acetic acid. 
 This being expensive, it is better to add common salt to the 
 solution ; hydro-chlorate of rosaniline and'arsenite of soda are 
 formed, by double decomposition, and the former salt being 
 insoluble in a concentrated saline solution, rises to the surface 
 and is collected. By re-crystallization a very pure hydro- 
 chlorate of rosaniline is formed, which can be used in this state. 
 
 Rosaniline may be precipitated by saturating the hydro- 
 chloric acid by caustic soda or lime, and, if pure, is colorless. 
 It is not very soluble in water, and is used for making other 
 salts. 
 
 Azaleine, rubine, often designated under the name of magenta, 
 are nitrates of rosaniline, 
 
 Roseine is the acetate of the same base. 
 
 Eosaniline is not the only base produced during the treat- 
 
ANILINE BLUES AND VIOLETS. 
 
 381 
 
 ment with arsenic acid ; other basic substances are formed, and 
 found in the residues; such are: Mauvaniline, chrysaniline, 
 and chrysotoluidine, of which we have given the formulae. 
 
 Aniline Blues and Violets. — An aniline violet was the 
 first aniline color manufactured. Discovered by Mr. Perkin, 
 in 1857, it is a sulphate of mauveine, known under the name 
 of Mauve, Indisine, &c, and produced by oxidizing sulphate of 
 aniline by bichromate of potassa. Tarry substances are formed 
 at the same time, which are removed by dissolving them in 
 hydrocarbons, such as naphtha. This violet or purple is hardly 
 soluble in water, but easily so in alcohol and sulphuric acid. 
 
 Chloride of lime made to oxidize a salt of aniline, produces 
 also this same color, taking care to stop the operation when 
 the desired shade has appeared. Chlorine, peroxide of manga- 
 nese, &c, with a salt of aniline, give similar results. The varia- 
 tions in the quality and the quantity of product, result from the 
 proportion of reagents employed, the length of the operation, 
 and the temperature applied. 
 
 In the above processes, aniline has been partially oxidized ; 
 in the following ones, the most oxidized compounds are brought 
 to a lesser degree of oxidation. 
 
 The Imperial purple of MM. Girard and de Laire is obtained 
 by heating together a salt of rosaniline, magenta, for instance, 
 with its own weight of aniline, at a temperature of 350° Fah., 
 and for several hours. All the unaffected aniline is removed 
 by weak acids, and the purple remains. 
 
 The Regina purple of Mr. Nicholson is magenta heated to a 
 temperature of 390° to 420° Fah.; the substance melts, evolves 
 ammonia, and the new color is produced. 
 
 Blues can be obtained from these violets, by washing them 
 several times with diluted hydrochloric acid, in order to dis- 
 solve all the aniline and magenta undecomposed, and also a 
 violet color. Aniline blues generally contain some violet, and 
 the violets some red shades in them. 
 
 We find in the trade, blues with violet shades, and violets 
 with red or blue shades. Repeated washings will remove the 
 violet, which is more soluble than the blue. But we must not 
 consider the violets as simple mixtures of blue and red; the 
 different shades are, as we have already seen, salts of rosani- 
 line in which part of the hydrogen has been replaced by the 
 radical phenyl. By varying the proportions of magenta and 
 aniline, and also the temperature, various shades of violet are 
 obtained. 
 
 A true blue is prepared, by adding to the mixture of magenta 
 and aniline, an organic acid or salt, such as benzoic, acetic acid, 
 or acetates. The blues thus obtained, are called Bleu de nuit, 
 
882 
 
 ANILINE YELLOWS. 
 
 Night blue, Bleu lumilre, on account of remaining blue under 
 artificial light. 
 
 Hofmanrfs blues and violets, known also under the name of 
 Iodine blues and violets, have been obtained by this chemist in 
 replacing three equivalents of hydrogen in rosaniline by the 
 radical ethyl = C 4 H 5 in the presence of iodine. 
 
 The blue color formed is a tri-ethylic rosaniline, whose 
 formula 
 
 To manufacture this salt— one part of magenta, two parts of 
 iodide of ethyl, and about two parts of strong methyl or ethyl 
 alcohol are heated in a close vessel (cast iron enamelled, or lined 
 with lead), at a temperature a little above 212° Fah., for three 
 to four hours. 
 
 These blues and violets are soluble in alcohol, not in water ; 
 but they may be rendered soluble in water by withdrawing 
 the iodine. An alkali heated with the dye, dissolves the iodine, 
 and the insoluble coloring matter, after washing, is dissolved in 
 muriatic acid. By this operation, there is a double gain : 
 first, saving the iodine; secondly, avoiding the use of alcohol 
 for dyeing. 
 
 For aniline blues and violets, a certain mixture of aniline 
 and toluidine is not so indispensable as in the manufacture of 
 aniline reds. In these substitution compounds, toluidine gives 
 blues by another radical, tolyl = C 14 H 7 , taking the place of 
 three equivalents of hydrogen. The toluidine blues are more 
 soluble than those of rosaniline. 
 
 The iodides of methyl, amyl, propyl, &c, may be used instead 
 of the iodide of ethyl. 
 
 Eeducing agents, such as nascent hydrogen, will transform 
 the salts of ethyl or phenyl-rosaniline, into colorless salts of 
 ethyl or phenyl-leucaniline. 
 
 Aniline Yellows. — Under the name of phosphine, aniline 
 yellows, victoria orange, chrysaniline yellow, the chrysaniline, which 
 we have already noticed in the secondary products of the 
 manufacture of aniline reds, is employed for dyeing, combined 
 with muriatic or acetic acid. 
 
 Mr. Vogel discovered a new dye, which he calls zinaline, by 
 treating a solution of magenta in water, by nitrous acid (N0 3 ). 
 
 We have also chrysotoluidine yellow, which is found associated 
 with violaniline and, mauvaniline, in the manufacture of hydro- 
 chlorate of rosaniline. 
 
 Aniline Orange has been extracted from the residues of the 
 manufacture of nitrate of rosaniline. 
 
ANILINE GREENS. 
 
 383 
 
 Aniline Greens. — Those who have worked the aniline salts 
 in laboratories, have frequently seen green efflorescences on 
 vessels containing these salts. The coloration was generally 
 due to atmospheric oxidation, and great difficulty has been 
 experienced in fixing that color; happily, chance helped the 
 constancy of the investigators. 
 
 Aldehyd green, aniline green, night green, vert lumifoe, &c, are 
 obtained by treating 4 parts of magenta, by 6 of oil of vitriol, 
 and 2 of water. Then 16 parts of aldehyd are added, and 
 the whole is kept at the temperature of boiling water, until a 
 few drops of the liquid give a blue color to a weak solution 
 of sulphuric acid. The liquid is then poured into a solution of 
 hyposulphite of soda, and the green is "fixed," as photographers 
 say. 
 
 This green bath can be used directly for dyeing; it does not 
 keep very long, but the color may be precipitated by tannin or 
 acetate of soda. The insoluble compound is employed for calico 
 printing, or forming new dye baths. 
 
 An iodide of ethyl green is produced by boiling Hofmann's 
 violet with water and carbonate of soda. The filtered liquor 
 is treated by picric acid, a green precipitate is formed which 
 is washed, dried, and sold in powder. It is soluble in alcohol, 
 &nd we believe in water, after trituration of the powder with 
 two or three times its weight of sal ammoniac. 
 
 There are also rosaniline and toluidine greens. 
 
 By the aldehyd process, rosaniline, or the most oxidized pro- 
 duct of aniline, has been "reduced" to green. The emeraldine of 
 MM. F. C. Calvert, Lowe and Clift, is, on the other hand, a pro- 
 cess of oxidation of aniline by chlorate of potassa. This new 
 process has what is remarkable, in common with aniline black, 
 which we shall examine further on, that the production of the 
 color, or the oxidation of the aniline salt, is effected upon the 
 dyed or printed fibre itself, and that it succeeds better on cotton 
 goods; while all other aniline colors have a greater affinity 
 for animal fibres, than for vegetable ones. 
 
 To produce emeraldine, the cotton fabric is prepared with 
 113 grains of chlorate of potassa per imperial gallon, and printed 
 with a mixture of 3 lbs. of tartrate or hydrochlorate of aniline, 
 6 lbs. of starch-paste, and 1 of chlorate of potassa. The salt of 
 aniline is added to the cold mixture of the two other substances. 
 
 After a few hours in the ageing room, a bright green gradu- 
 ally appears, which is then washed. If the green fabric is 
 passed through a solution of bichromate of potassa, the color 
 is transformed into a dark indigo blue, called azurine, and which 
 is the result of a further oxidation of the green color. This 
 green turns blue by the action of soap or alkalies, but acids 
 restore the primitive color. 
 
384 ANILINE BLACKS AND GRAYS. 
 
 Aniline Blacks and Grays. The same as for emeraldine 
 green, these colors are developed upon the cotton fibre itself. 
 Mr. Lightfoot, who discovered the aniline black, if black is a 
 color, used a paste composed of chlorate of potassa, hydro- 
 chlorate of aniline, sulphate or chloride of copper, and starch 
 enough to thicken. By the mutual oxidizing reaction of chlorate 
 of potassa and chloride of copper, the aniline is oxidized to the 
 degree of black. This paste was open to the objection of destroy- 
 ing rapidly the steel scrapers of the printing rollers, on account 
 of the presence of a large quantity of a salt of copper. 
 
 Further experiments made by MM. Cordillot, C. Kcechlin 
 and Lauth, led to these important facts, viz: that the hydro- 
 chlorate or nitrate of aniline are the only aniline salts which 
 can produce a black ; that the best aniline ought to be a mix- 
 ture of aniline and toluidine; that the presence of copper is 
 indispensable; and that a sulphide of copper, prepared by 
 precipitation, will not corrode the steel parts of the printing 
 machine, and will gradually absorb the quantity of oxygen for 
 its transformation into sulphate. 
 
 If a tartrate or acetate of aniline is used, it is necessary to 
 add to the mixture a certain quantity of sal ammoniac, which 
 will furnish the muriatic acid necessary for the transformation 
 of the tartrate or acetate of aniline into a hydrochlorate. With 
 these data, a good printing paste is made by mixing together, 
 when cold, the two following mixtures, made separately : — 
 
 I. — Heat and digest in water . 
 
 Starch 
 
 Precipitated sulphide of copper 
 
 II. — Water . . . . . 
 
 Torrefied starch 
 Solution of gum tragacanth . 
 Hydrochlorate of aniline 
 Sal ammoniac . , . 
 Chlorate of potassa 
 
 For dyeing cotton or silk, M. Cam. Kcechlin proposes a bath of 
 
 Water .... 20 to 30 parts. 
 Chloride of potassa . . . 1 " 
 
 Sal ammoniac . . . . . 1 u 
 Chloride of copper . . . . 1 " 
 
 Aniline 2 " 
 
 Hydrochloric acid . . . . 2 " 
 
 The drying is made in ageing rooms, and the color appears 
 at its true shade only after washing. 
 
 The oxidation is such, that if the goods dyed or printed were 
 
 50 
 
 parts. 
 
 100 
 
 U 
 
 25 
 
 (( 
 
 185 
 
 it 
 
 120 
 
 u 
 
 100 
 
 a 
 
 80 
 
 « 
 
 10 
 
 u 
 
 30 
 
 u 
 
COLORS DERIVED FROM CARBOLIC OR PHENIC AGID. 385 
 
 A> 
 
 left wet andTolded, or in heaps, there would be danger of spon- ^ 
 taneous combustion. Hence the necessity of drying immedi- 
 ately. 
 
 Aniline grays are obtained by diminishing the proportion of 
 the black producing substances of the above receipts, but keep- 
 ing as much free acid as in the primitive mixture for black. 
 
 The Mauveine gray of Mr. J. Castelhaz is mauveine blue 
 "reduced" by aldehyd in the presence of sulphuric acid. 
 
 Mureine grays of different shades are produced by MM. F. 
 Carves & Thirault, of St. Etienne, by treating, in various 
 proportions, hydrochlorate of aniline by a mixture of bichro- 
 mate of potassa, an iron salt, water, and sulphuric acid. These 
 grays are soluble in boiling water, and are employed in the 
 same way as the majority of aniline colors. 
 
 Aniline Browns and Maroons. — The brown maroon of Mr. 
 de Laire is made by melting 4 parts of anhydrous hydrochlo- 
 rate of aniline with 1 of dry aniline oil, the temperature being 
 slowly raised up to 465° Fah. The operation is over when 
 yellow vapors begin to appear, and the mass is suddenly trans- 
 formed into brown. The color is soluble in water. 
 
 Leucaniline brown is obtained by Mr. Horace Koechlin in the 
 following way: A salt of rosaniline is transformed into leu- 
 caniline by zinc powder. The leucaniline is separated from 
 the zinc by alcohol, and this being evaporated, a tartrate of 
 leucaniline may be formed, which is afterwards transformed 
 into brown by the oxidizing action of a mixture of sulphide of 
 copper and chlorate of potassa. 
 
 Another aniline brown is made by boiling a concentrated solu- 
 tion of chromate of ammonia with aniline, and adding formic 
 acid. This operation is somewhat expensive. 
 
 Colors Derived from Carbolic or Phenic Acid. 
 
 We have already seen how carbolic or phenic acid wa£ ex- 
 tracted from coal-tar. If aniline is an amide of the radical 
 phenyl, and is sometimes called phenylamine, phenic acid is also 
 closely related to.it, being an oxide of phenyl=C 12 H 5 0. More- 
 over, the aniline found already formed in the coal-tar, proceeds 
 from the reaction of phenic acid upon the ammonia which is 
 always produced by the decomposition of bituminous coals. 
 The reaction takes place by an elevation of temperature, or 
 pressure, or both, and is as follows: — 
 
 Ammonia. Phenic Acid. Aniline. Water. 
 
 NH 4 0 + C 12 H 5 0 = C ]2 H 7 N + 2H0. 
 
 25 
 
386 COLORS DERIVED FROM CARBOLIC OR PHENIC ACID. 
 
 For these reasons, we prefer the name of phenic acid to that 
 of carbolic, which does not bear any relation to the radical 
 phenyl=C 12 H 5 . > 
 
 Phenic acid, partially oxidized, gives rise to 
 
 The operation is performed by MM. Guinon, Mamas & Bon- 
 net of Lyons, by heating together 23 parts of phenic acid with 
 10 to 20 of oxalic acid, and 7 to 14 of oil of vitriol. The rosolic 
 acid produced is insoluble in water, and affords only very fugi- 
 tive red shades upon fabrics. 
 
 The Peonine or Coralline, discovered by Mr. J. Persoz, is the 
 product of the reaction of ammonia on rosolic acid, heated 
 together in closed vessels at a temperature of 300° Fah. This 
 red dye is soluble in alcohol, alkaline solutions, acetic acid, &c. 
 It is not very fast, and is acted upon by sulphurous acid. 
 
 Azuline is a blue dye formed by heating together 5 parts of 
 coralline with 6 to 8 of aniline. 
 
 Picric acid, Carboazotic acid or Trinitrophenic acid is the result 
 of the oxidation of picric acid by nitric acid, and has for its 
 formula : — 
 
 It dyes animal fibres yellow, with a slight green tinge. The 
 picrates sold under the name of picric acid or that of aniline 
 yellow should be discarded, as they are highly explosive, and 
 do not dye as well or so much as pure picric acid. It is suffi- 
 ciently soluble in water for dyeing. 
 
 Isopurpuric acid is made by adding, gradually, a solution of 
 picric acid to another solution of cyanide of potassium. Am- 
 monia and prussic acid are evolved, and purpuric acid crystal- 
 lizes when the liquor is cold. Under the name of soluble ruby, 
 are sold isopurpurates of potassa, or ammonia, which dye red 
 like murexide. The latter salt dyes silk and wool mordanted 
 with corrosive sublimate a magnificent purple, and a beautiful 
 yellow with zinc mordants. The colors are fast, except against 
 sulphurous acid fumes. 
 
 All the salts formed by isopurpuric acid detonate freely 
 when dry ; they should therefore be sold and kept in paste ; 
 with an addition of glycerin for greater security. 
 
 Picric acid greens are made by dyeing with a mixture of ani- 
 line blue and picric acid, which appears grayish under artificial 
 light; by picric acid and carmine of indigo ; and by picric acid 
 and Prussian blue, which remains green under artificial light. 
 
 Phenicienne, or Rothine, from the discoverer, Mr. J. Roth, is 
 
 Rosolic Acid. Phenic Acid. 
 
 C 24 H l2 O a = 2(C 12 HA) + 20. 
 
COLORS DERIVED FROM NAPHTHALINE. 387 
 
 the result of the action of azoto-sulphuric acid upon phenic 
 acid. It is a brown color, little soluble in water, but very 
 soluble in alcohol, acetic acid, and alkalies. It dyes fast colors, 
 whose shade varies with the mordants employed, but does not 
 bear well the steaming process. 
 
 Aniline or, Picric acid broivn,\s obtained by Mr. E. Jacobsen, 
 by gradually heating up to 302° Fah. 1 part of picric acid and 
 2 of aniline. Ammonia is evolved. This color is soluble in 
 alcohol with an addition of sulphuric acid or glycerine. 
 
 Colors Derived from Naphthaline. 
 
 We have seen at the beginning of this chapter how naphtha- 
 line may be extracted from coal tar. This substance, which has 
 been the subject of such profound study by Laurent, and was 
 suggested by that chemist as being a source of coloring sub- 
 stances, has been again submitted to many experiments since 
 the success of aniline colors. A quantity of dyes have already 
 been discovered, but most of which, not being fast, have been 
 abandoned. This is to be regretted, because naphthaline can 
 be had much cheaper than benzole or toluole. Nevertheless, 
 we think, this want of success will be overcome. A very near 
 approach to the artificial production with naphthaline of alizarin, 
 the coloring principle of madder, has been made by Mr. Z. 
 Eoussin. 
 
 Naphtha lamine, or Naphthylarnine, is to naphthaline what ani- 
 line is to benzole, and is obtained by similar processes. Heated 
 with arsenic acid, or nitrate of mercury, it produces fine purples, 
 which are insoluble in water, but soluble in alcohol, and would 
 have been used in dyeing, had they been fast. 
 
 Blue colors have also been obtained. 
 
 No phthylamine yellow — JauneoVor — Manchester yellow, is a mag- 
 nificent yellow prepared by treating the hydrochlorate of naph- 
 thylamine by nitrite of soda, and afterwards with nitric acid. 
 Dr. C. A. Martius, the discoverer, considers this substance as 
 an acid analogous to picric acid, and calls it binitro-naphthylic 
 acid. It is superior to picric acid, the shades being pure yel- 
 low, and supporting well the steaming process. 
 
 Chloroxynaphihalate of ammonia, according to Mr. Perkin, 
 dyes silk a gold yellow, which stands light very well. This 
 salt is very soluble in water. 
 
 Chloroxynaphthalic acid=C 10 H 5 C10 3 is sufficiently soluble in 
 boiling water for dyeing purposes. It dyes wool a deep red ? 
 without mordants. It is too acid to be used for cotton. If 
 the wool has been previously dyed with sulphate of indigo, a 
 fine black will appear. The sulphate of indigo, may also be 
 mixed directly, with the chloroxynaphthalic acid. 
 
388 REMARKS IN GENERAL ON COAL TAR COLORS. 
 
 Eemarks in General on Coal Tar Colors. 
 
 As a general thing, all the aniline colors are very little solu- 
 ble in water; the blues are the most insoluble, and the violets 
 or purples next. At the temperature of boiling water, 
 however, the reds are rendered sufficiently soluble for dyeing, 
 and the more so, when we consider that the bath should not 
 contain too much coloring matter. 
 
 The true solvents of these dyes are alcohol, methylic alcohol 
 or wood spirit, acetone, acetic and tartaric acid, sulphuric acid, 
 &c. "Wood spirit, when not perfectly pure, will turn aniline 
 reds violet or blue; this is probably due to essential oils con- 
 tained in this methylic alcohol, and which have a reducing 
 action similar to that of aldehyd. 
 
 When alcohol is used as a solvent, its proportion is variable 
 with the substance it has to dissolve. 
 
 50 parts of alcohol for 1 of blue. 
 30 " " " " 1 of violet, 
 
 are good proportions. The iodine blues and violet, where the 
 iodine has been left, require less alcohol. 
 
 The solution is effected in copper or glazed vessels, which 
 can be heated, and are provided with condensing worms, in 
 order to save the alcohol which distils over. The solution is 
 allowed to stand, filtered, and thrown into about eight times 
 as much of boiling water, to which some tartaric or acetic acid 
 has been added. For economy's sake, sulphuric acid may be 
 used instead of the organic acids, which, however, are to be 
 preferred, if very fine shades are required. It is this " con- 
 centrated solution" which will be made use of for gradually 
 coloring the dye bath. 
 
 All aniline colors precipitate by the addition of a solution 
 of tannin (pure, or decoctions of sumac or of gall nuts). The 
 tannate formed is soluble in alcohol, acetic acid, or diluted 
 sulphuric acid. 
 
 They are also insoluble in concentrated solutions of alkaline 
 salts, such as chloride of sodium (common salt), acetate and 
 sulphate of soda, &c. This property is frequently made use of 
 for recovering the color from old baths, or purifying these dyes 
 in course of manufacture. 
 
 The expenses resulting from the employment of alcohol for 
 their dissolution, has caused several methods for rendering these 
 colors soluble in water. Decoctions of certain roots have been 
 proposed, and have not been very successful. 
 
 Concentrated sulphuric acid, with or without the aid of heat, 
 dissolves the aniline blues and violets, and by subsequent re- 
 
DYEING WITH COAL TAR COLORS. 
 
 389 
 
 precipitation of the color by the addition of a large volume of 
 water, it is rendered sufficiently soluble in hot water. This 
 process succeeds better with the blues than for the violets, the 
 shade of which is not so pure as before. Even for the blues, 
 part of their fastness is taken off, principally when the solu- 
 tion has been made in hot sulphuric acid. 
 
 Soluble Blues or Violets are those colors treated by sulphuric 
 acid. Too much solubility would be a defect in dyeing ; all that 
 is required is that the bath should dissolve enough of the color 
 to replace that taken by the stuff, and that the color should not 
 fall to the bottom. 
 
 It is at present rare, to find impure aniline colors in the trade; 
 the impurities consist generally of resinous and tarry substances, 
 formed during the manufacture, and which can be removed by 
 several washings with coal naphtha, coal oil, and other hydro- 
 carbons, which do not dissolve the color. 
 
 If the dye is soluble in boiling water, an addition of fine and 
 sharp sand will cause the impurities to stick to it. Filtration 
 terminates the operation. 
 
 The colors derived from phenic acid and naphthaline are often 
 more soluble than those from aniline. 
 
 Eemarks in General on Dyeing with Coal Tar Colors. 
 
 It is generally more easy to dye with coal tar colors, than 
 with the other dyes hitherto used; at least, as regards animal 
 fibres. Nevertheless certain precautions are necessary. 
 
 The animal fibres, wool and silk, have such an affinity for these 
 colors, that they will immediately deprive a bath of its coloring 
 matter, and be unevenly dyed. This points to a constant work- 
 ing of the stuff while in the bath, and to a gradual addition of 
 the coloring substance to the vat. The more soluble the color 
 is, the more these conditions should be attended to. 
 
 The addition of some acid, generally sulphuric, tends to make 
 the color more soluble. In the case of certain blues rendered 
 too soluble, the bath should not contain any acid; sometimes 
 a small quantity of alkali will be found useful. 
 
 The degree of acidity, and the temperature of the bath, have 
 an influence on the shade. Indeed, many shades of the same 
 color are produced by varying the temperature. The hotter 
 and the more acid a bath is, the bluer are the shades. On the 
 other hand, a bath cold and with little acidity gives red shades. 
 Nevertheless, the goods will be dyed faster if the temperature 
 has been raised near the boiling point; and if red shades are 
 desired, the goods are allowed to rest in the bath until it has 
 cooled off. 
 
390 
 
 DYEING WITH COAL TAB COLORS. 
 
 The temperature for dyeing wool is generally greater than 
 that for silk. 
 
 The color being dissolved, as we have explained previously, 
 is gradually added to the bath, the temperature of which is 
 about 120° Fah. at the beginning of the operation, and is gra- 
 dually raised up to 185°, and even to the boiling point. In 
 the meantime the goods are worked or drawn several times, in 
 order to be dyed evenly. 
 
 Vegetable fibres, except in the case of emeraldine green or 
 aniline black, are without affinity for aniline colors. On that 
 account it is necessary to "animalize" them, that is to say, to 
 impregnate them with certain organic mordants, which will 
 impart to them the property of attracting and fixing these dyes. 
 
 The mordants employed for this purpose are : Albumen from 
 eggs or from the blood, the latter only for dark shades; 
 lactarine or caseine (curd of milk), dissolved in caustic soda or 
 acetic acid; gluten, in the same solvents; gelatine, and tannate 
 of gelatine; tannin pure, or decoctions of sumach or gall nuts; 
 soap and the transformed oils, as for Turkey red ; stannate of 
 soda and other metallic salts, &c. The best of all, if it were 
 not for its cost, would be the albumen of the white of egg. 
 The color attracted and fixed by this substance, becomes fast 
 on the fibre by the coagulation of the albumen during the 
 steaming process. 
 
 If gelatine is employed, the further addition of tannin will 
 form an insoluble compound, which will retain the color al- 
 ready fixed upon the fibre. Tannin and metallic salts form, also, 
 insoluble tannates. 
 
 Steaming makes the colors more fast, and is also a test of 
 the solidity of many dyes. At the beginning, the steam is let 
 out under a small pressure, which is afterwards gradually in- 
 creased, but is never very high. 
 
 Tannin alone, does not give very fast colors; the fabric had 
 better be mordanted previously with a metallic salt; it succeeds 
 better with blues than with magenta, and even violets. 
 
 For instance, a good process for dyeing cotton consists in 
 passing the cloth through a decoction of sumac, or any other 
 substance holding tannin, for one hour or two, and afterwards 
 through a weak solution of stannate of soda. After being 
 worked there for one hour, it is wrung out, and dipped into 
 weak sulphuric acid and well rinsed. It is then ready to be 
 dyed in an aniline color bath, slightly acidulated. 
 
 For calico printing, the cotton may have been previously 
 mordanted, as we have said, and then printed, steamed and 
 washed. The mordant and the color are sometimes printed at 
 the same time, as with albumen for instance; or the color may 
 
COLORING POWER AND NATURE OF ANILINE COLORS. 391 
 
 be printed first, and passed through the mordanting bath; the 
 first process seems preferable. • 
 
 For raising the shades, a passage through an acidulated liquor 
 is sometimes resorted to. 
 
 The discharges are made by means of powder of zinc, which 
 transforms the salts of rosaniline into white leucaniline. This 
 substance being little soluble, the washings are often insuffi- 
 cient to remove it entirely, and what remains on the cloth will 
 be oxidized by the air, and transformed again into colored 
 salts of rosaniline. By the use of the permanganate of potassa 
 or lime, on the contrary, the aniline color is destroyed. The 
 permanganic acid is set at liberty by sulphuric acid, which 
 unites with its base. Inorganic substances, such as kaolin, 
 freshly precipitated silica and alumina, are added to it, in order 
 to form a paste, and the mixture is printed. The destroyed 
 aniline color is replaced by an oxide of manganese, which is 
 removed by washing with sulphurous acid, or by a mixture of 
 hydrochloric acid and protochloride of tin, if the remaining 
 color, like coralline, is acted upon by the sulphurous acid. 
 
 Many more colors, and processes of dyeing and calico print- 
 ing could here be described ; but we must remain within 
 the limits of this work, the object of which is to explain the 
 chemical phenomena of the art of dyeing, rather than to be a 
 book of receipts. We shall finish this article by the description 
 of a simple process to ascertain the coloring power and the 
 nature of aniline colors, which we borrow from M. Riemann's 
 book on aniline. 
 
 Determination of the Coloring Power and Nature of 
 Aniline Colors. 
 
 Dissolve 10 grains of the color in 1 fluidounce of alcohol, 
 in a vessel heated by a water bath. The liquid is well 
 shaken, next allowed to settle, decanted into a graduated 
 tube, and what remains undissolved treated again in the 
 same manner with another fluidounce of alcohol. All the 
 color being dissolved, a tube graduated into 100 parts, is 
 filled with the whole of the alcoholic solution, plus some alco- 
 hol to fill up entirely to the last graduation. The tube, there- 
 fore, should be of a capacity to hold at least the quantity of 
 alcohol used for the solution. 
 
 In a china basin a sufficient quantity of water is heated, until 
 it is too hot to put the finger in. Then 20 grains of fleecy 
 wool are weighed, put into the warm water, and moved about 
 with a glajs rod until the wool is thoroughly wetted. It is then 
 
392 
 
 IDENTIFICATION OF ANILINE COLORS. 
 
 taken out, and 4 divisions of the colored solution are added and 
 well mixed. The wool is then*once more cautiously immersed. 
 It will now be dyed by the solution, and when all the color is 
 fixed, a fresh portion of the solution is added to the bath, until 
 all the wool is dyed of the desired shade. 
 
 The value of the coloring matter under examination is in 
 inverse ratio to the quantity of the solution consumed. If 10 
 divisions of the standard solution a were necessary to dye 20 
 grains of the same fleecy wool a certain shade, and 14 divisions 
 of the color under examination b produced the same effect, the 
 proportion is 14 : 10 :: a : b. Hence b is f of a. 
 
 Identification of Aniline Colors. 
 
 Aniline colors may be distinguished from one another, and 
 for this purpose Mr. J. J. Pohl uses fuming hydrochloric acid, 
 and a dilute acid consisting of one part strong acid to three 
 parts of water. 
 
 The effects of the fuming acid are observed at the ordinary 
 temperature at the time of application, after 5, and after 15 
 minutes; also the effect of dilution is then observed. Next, 
 the effects of the dilute acid are observed at first and after 15 
 minutes. Finally, the same test is repeated after a considerable 
 dilution with water. 
 
 The following table shows the results of observations made 
 upon the several aniline colors: — 
 
IDENTIFICATION OF ANILINE 
 
 COLORS. 
 
 393 
 
 P. £ 
 
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 .2 2 
 
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 3 M 
 
 S ^ EM H 
 
 £ d > 
 
 o fl S . 
 
 5 * g 
 
 £ « ° 
 
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 5 .rH T3 
 
 i-o £ 
 
 Hi 
 
 d 
 ft 
 
 ce o 
 
 o ce 
 
 O o3 
 
 £ BS 
 
 fa w 
 
 t= fa 
 Hi 
 
 s £ 
 
 si 4 
 
 a t3 
 
 £ o3 
 
 2^ 
 
 s -*j 
 
 <=> * ^ 
 03 2 
 
 fa .2 ^ 
 
 j| > £ 
 
 ~rd 3 
 
 c3 <r> 
 
 rd e3 aa 
 
 Eh 
 
 drd 
 
 o 
 
 03 
 
 ft 
 
 O 03 
 
 III 
 
 " o £ 
 c3^~ 
 
 Q 
 
 rd r-j • 
 
 So 
 
 2^ ^21 
 I d£ 2 
 
 r> 03 gj S 
 
 I .ll *2 
 
 ft U 
 
 rS I 
 
 CI 
 
 <D 3 
 
 rH O 
 8 5 
 
 ^1 
 3 rH ^ 
 rC 
 
 fa r* "~ 33 
 krl ^ M 
 
 *** aS rH 
 
 £ ? rt ® 
 'h a n 'o 
 
 P 5 - -2 
 
 • rH J) O 
 
 Sal f & 
 
 ft O 
 
 2 1 
 
 <U 03 
 
 r2S 
 
 PQ 
 
 r2 
 
 rd cr 1 
 3 
 
 m 
 
 rd . 
 
 o 
 
 .2 ►» 
 ^ d 
 
 d © CO 
 
 IS g 
 
 5i > B 
 
 ft ^ 
 
 ft 
 
 < 
 
 d d 
 ■2 g 
 
 S d 
 
 o> o 
 
 H O . 
 
 ft Q « 
 
 6- 5 S> 
 Ph X g 
 
 2 oi w 
 SOW 
 
 h3 c3 
 
 So 
 
 fa 55 
 
 O O 
 
 'o 'd 
 
 a* 
 
 3 s 
 
 c3 ? 
 
• 
 
APPENDIX. 
 
 DYEING AND CALICO PRINTING AS SHOWN IN THE UNIVERSAL 
 EXPOSITION, PARIS, 1867. 
 
 Extracts from the Reports of the International Jury* and from 
 
 other Sources. 
 
 It is well known that silk, by the process of dyeing, can have 
 its weight increased 10 to 40 per cent., and yet give products 
 of a good quality. The competition and the dearness of silk 
 have been so great of late years, that, often, the weight of silk 
 is increased 150 to 200 per cent, by dyeing, especially for 
 blacks. 
 
 Such silk is rough to the touch, without lustre, easily cut, 
 and will not last. Heated to about 230° Fah., it will fall to 
 pieces. 
 
 By this process of over adulteration, silk increases much in 
 volume, and the fibres, viewed under the microscope, are 
 swollen. The swelling is also sensibly in proportion with the 
 increase of weight. 
 
 With mordants of tannin, tin, and oily substances, nearly all 
 the new coal-tar colors have been fixed on vegetable fibres. 
 
 Mr. Eeimann, of Berlin, dyes cotton yarn with aniline colors, 
 and without mordant, by effecting the operation in closed ves- 
 sel^ heated up to about 300° F. The shades, on leaving the 
 apparatus, are said to be fast, but not bright. They are raised 
 by another dyeing operation conducted in the open air. 
 
 Such a process requires costly apparatus, does not allow an 
 easy dyeing to a given shade, and, granting that the dyed 
 ground is fast, it does not appear that the raising given after- 
 wards will be faster than by the ordinary process. Neverthe- 
 
 * Rapports du Jury International, publies sous la direction de M. Michel 
 Chevalier, Membre de la Commission Imperiale. 13 vols. 8vo. Paris, 1868. 
 
396 
 
 APPENDIX. 
 
 less, the application of dyeing under pressure in closed vessels, 
 is a curious one, and might be used to advantage in other cases. 
 
 Since Messrs. Tessie du Motay and Mardchal have succeeded 
 in producing cheaply alkaline permanganates, these salts begin 
 to be used for bleaching goods. By the decomposition of the 
 permanganate, its oxygen destroys or modifies the substances 
 foreign to the cloth, which are washed out. At the same time, 
 oxide of manganese is precipitated upon the cloth, and is re- 
 moved by washing in a dilute sulphurous acid solution. The 
 solution of permanganate of soda is also to be employed in 
 a dilute state. 
 
 Feathers may be bleached by the process of Messrs. Viol and 
 Duflot, as follows : Steep the feathers for from three to four 
 hours in a tepid and diluted bath of bichromate of potassa with 
 nitric acid, then pass through another bath holding a very weak 
 solution of sulphurous acid, and rinse. 
 
 Dyeing aniline black on wool has not been entirely success- 
 ful, notwithstanding the chlorine process of Mr. Lightfoot. 
 Some recent experiments, however, permit us to hope that ani- 
 line black will be employed for wool as well as for cotton. 
 
 Casein (curd of milk), as a mordant, is better dissolved in 
 crystallizable acetic acid, or in a milk of lime. In the latter 
 case, the colors are said to be faster than when using casein 
 dissolved in ammonia water, or even than with albumen. 
 But printing should be effected rapidly, because the paste 
 loses its fluidity very rapidly, especially with ultramarine. 
 
 By means of a metallic engraving in relief, which distributes 
 drops of colored and melted resin on silk goods, Mr. Petitdidier 
 imitates embroideries and tapestry work. 
 
 Light tissues, like tulle or bobbinets, are also covered with 
 drops of gelatin, or gum, which fall from rows of pins, variously 
 arranged, according to the processes of Messrs. C. Depouilly, 
 Meyer, and Agnelet brothers. 
 
 By printing, in a peculiar way, silk warps previous to weav- 
 ing, various combinations of figures and designs may be effected 
 on the loom, without the expense of the cartoons of the 
 Jacquart loom. 
 
 The various aniline blacks, prepared whether by the bichro- 
 mate of potassa, or by the chlorate, are soluble in a mixture of 
 
APPENDIX. 
 
 397 
 
 alcohol and sulphuric a6id. This solution, thrown into a large 
 quantity of water, dyes animal fibres a fast gray. 
 
 For dyeing black on cotton, Messrs. Paraf and Javal, pass the 
 cloth through a bath containing a mixture of sulphate of ani- 
 line and bichromate of potassa. The color appears on the 
 fabric immediately after it leaves the bath, the temperature of 
 which must be kept a little below the freezing point, not above. 
 
 Another method consists in mordanting the cotton cloth 
 with chromate of lead, and then passing it through an acidu- 
 lated bath of oxalate of aniline. In this case, the reaction 
 taking place only on the cloth, the temperature has not to be 
 so strictly low as in the former method. 
 
 Mr. Dumas frees indigo from its red and brown coloring 
 substances by aniline. Indigo thus purified gives very good 
 results when used in printing on cotton. 
 
 One of our cotemporaries speaks of chloroform as being a 
 solvent of indigo. Not having tried the process, we can but 
 believe that the chloroform may be a solvent of the impurities 
 of indigo, rather than of indigo itself. 
 
 From the same source we find for dyeing animal fibres a 
 silver gray color : Boil 10 pounds of wool in a bath containing 
 4 ozs. of sulphuric acid, and 4 ozs. of glauber salts (sulphate of 
 soda). Then dye to the shade by means of iodine violet and 
 some carmine of indigo. 
 
 There are many recipes for the preparation of the printing 
 paste for aniline black ; they can be summed up into a com- 
 position of tartrate of aniline, sulphide of copper, chlorate of 
 potassa, and sal-ammoniac, the whole thickened with a mix- 
 ture of starch and torrefied starch, with enough water to make 
 the volume of the aniline about one-tenth of the whole. 
 
 Aniline black succeeds very well when printed with or under 
 chrome orange. In this case the lead mordant is basic. 
 
 Mr. Horace Koechlin has succeeded in printing aniline greens 
 on silk and wool by adding alkaline sulphites to the color. 
 
 For cotton goods, besides the sulphite, some tannin is neces- 
 sary. 
 
 The following are the values in coloring power of several 
 madder extracts: — 
 
 That of Professor Eochleder, of Prague, is dry and equal to 
 140 times its weight of madder ; that of Messrs. Pernod and 
 Picard, of Avignon, is in paste and equal to 16 to 20 times its 
 
398 
 
 APPENDIX. 
 
 weight of madder; that of Mr. Schutzenberger, manufactured 
 by Mr. C. Meissonnier, is also in paste and equal to 30 times 
 its weight of madder. 
 
 These extracts are free from resinous matters, and therefore 
 can be thoroughly mixed with water, but they require a nice 
 adjustment in the proportion of mordants. The steaming pro- 
 cess lasts two or three times as long as with ordinary steam 
 colors. The shades are also to be raised by drawing the 
 printed goods through soap baths. No mixture of acids, 
 oxidizing agents, or ageing is necessary. The principal mor- 
 dants still used are those of alumina and iron. 
 
 On the other hand, some persons assert that it is possible to 
 print with these extracts, on tissues which have not been mor- 
 danted. 
 
 Rosin soap, for bleaching cotton goods, has been used for 
 several years, instead of ordinary soaps. Besides its cheap- 
 ness, the action of this soap is more effective, removing entirely 
 the resinous substances of the cotton goods, probably in accord- 
 ance with the rule that "like dissolves like." Soda ash is also 
 used in connection with rosin soap, and its action is facilitated 
 when the goods have been previously submitted to the liming 
 process. Rosin soap, combining with the soap made by the 
 alkali and the fatty matters on the goods, prevents the decom- 
 position of the latter soap, which often takes place in presence 
 of saline matters, and produces blotches on the bleached goods. 
 
 One of the main improvements in bleaching calicoes, has 
 been that of effecting the operation under high pressure, by 
 forcing the scouring liquor to circulate through the cloth. 
 
 Another improvement consists in transforming the starch, 
 which enters into the composition of sizing for the warps, into 
 dextrine or sugar, easily removed. For this purpose, the 
 pieces are soaked in water at the temperature of 140°, to 
 which a small quantity of malt is added, and causes the above- 
 named transformation. 
 
GLOSSARY OF TECHNICAL TERMS 
 
 USED IN THE DYE-HOUSE, 
 
 WITH THE CHEMICAL NAMES : 
 
 A FULL EXPLANATION OF WHICH MAY BE OBTAINED IN THE VOLUME. 
 
 Adjective. A term applied to a color depending on a base for its pro- 
 duction. 
 Aqua-fortis. Nitric acid. 
 
 Aqua-regia. A mixture of hydrochloric and nitric acids, generally In 
 
 the proportion of 2 of the former to 1 of the latter. 
 Alkali root. Alkanet root. 
 
 Alterant. A substance added to a color to give it brightness, same as 
 " raising." 
 
 Argol. Bitartrate of potash, formed by deposit in wine casks. 
 Am otto. Annotta. 
 
 Barilla. The name of an impure soda imported from Spain and the 
 Levant. 
 
 Black ash. Carbonate of potash in fused masses, as imported. 
 Black lead. Carburet of iron, Plumbago. 
 Black iron liquor. Acetate of iron, or pyrolignite of iron. 
 Bleed. To extract the coloring matter from a dye drug. 
 Bleaching 'powder. Chloride of lime. 
 
 Block tin. Commercial tin cast into ingots or blocks, not so pure as 
 
 grain tin. 
 Borax. Borate of soda. 
 Blue copperas. Sulphate of copper. 
 Blue-stone. Sulphate of copper. 
 Blue vitriol. Sulphate of copper. 
 
 Bottom. Applied to the base of a color such as sumach, galls, &c. 
 Brimstone. Sulphur. 
 
 Brown sugar. Acetate of lead, or pyrolignite of lead. 
 Bucking. Boiling goods in alkalies, sometimes Bowking. 
 Bundle. Ten pounds of cotton yarn. 
 Calomel. Protochloride of mercury. 
 
 Carmine. Coloring matter of cochineal, extracted and dried. 
 Chamber lye. Urine. 
 
 ChemiCj or chemic blue. Sulphate of indigo. 
 Chrome. Bichromate of potash. 
 
400 
 
 GLOSSARY. 
 
 Common salt. Chloride of sodium. 
 Copperas, Protosulphate of iron. 
 
 Corrosive sublimate. Bichloride of mercury. • 
 Cream of tartar. Bitartrate of potash, purified. See argol. 
 Crofting. Exposing goods upon the grass for bleaching. 
 Crude tartar. See argol. 
 
 Dip. Generally applied to immersing goods in the blue vat. 
 Doctored. To adulterate, generally applied to giving an appearance 
 
 of strong color to dyewoods, by adding water to them. 
 Double muriate of tin. Bichloride of tin. 
 Epsom salts. Sulphate of magnesia. 
 Essential salt of lemons. Binoxalate of potash. 
 Extract of Indigo. Sulphate of indigo. 
 Fast Color. Permanent color. 
 Fancy Color. Colors subject to fade, fugitive. 
 Feathering. To granulate a metal. 
 
 Firing spirits. When tin by dissolving too rapidly or by heat, be- 
 comes converted into a bichloride. 
 
 Fluery of a vat. The froth of oxidized indigo floating on the surface 
 of a blue vat. 
 
 Flowers of zinc. Oxide of zinc. 
 
 French tub. Protochloride of tin and logwood, plump tub. 
 
 Glauber salts. Sulphate of soda. 
 
 Grain tin. Metallic tin in prismatic pieces. 
 
 Green vitriol. Sulphate of iron, copperas. 
 
 Hartshorn. Ammonia. 
 
 Kelp. Ashes left on burning sea-weed. 
 
 Killing. Dissolving any substance in an acid, as iron in nitric acid, 
 
 killing iron. 
 King's yellow. Sulphuret of arsenic. 
 
 Lactine. A curd of milk used for annualizing cotton, lactarine. 
 
 Lemon juice. Citric acid. 
 
 Lye. Solution of an alkali, as potash or soda. 
 
 Lime shell. Caustic lime. 
 
 Limestone. Carbonate of lime. 
 
 Litharge. Protoxide of lead. 
 
 Lunar caustic. Nitrate of silver. 
 
 Magnesia nigra. Manganese. 
 
 Marine acid. Hydrochloric acid. 
 
 Mineral alkali. Soda. 
 
 Mordant. Generally applied only to acetate of alumina. 
 Muriatic acid. Hydrochloric acid. 
 Muriates. Chlorides. 
 
 Nitromuriate of tin. A solution of tin in nitric and hydrochloric 
 
 acids, forming a persalt. 
 Nitre. Nitrate of potash. 
 Oxymuriate of tin. Perchloride of tin. 
 Oxymuriate of potash. Chlorate of potash. 
 Oxymuriatic acid. Chlorine. 
 Oil of vitriol. Sulphuric acid 
 
GLOSSARY. 
 
 401 
 
 Orpiment. Sulphuret of arsenic. 
 
 Oxygen of the bleachers. Chlorine, chloride of lime, bleaching pow- 
 der. 
 
 Pearlash. Carbonate of potash. 
 
 Permuriate of tin. Perchloride of tin. 
 
 Prussiate of potash. Ferrocyanide of potassium. 
 
 Queen-wood. Brazil-wood. 
 
 Quicksilver. Mercury. 
 
 Raising. See alterant. 
 
 Realgar. Sulphuret of arsenic. 
 
 Red chrome. Bichromate of potash. 
 
 Red liquor. Acetate of alumina. 
 
 Rot steep. Steeping cloth in old lyes to soften the paste; fermenta- 
 tion takes place, hence the name. 
 Roman vitriol. Sulphate of copper. 
 
 Saddening. Making a color darker by means of a salt of iron. 
 Sal ammoniac. Chloride of ammonium. 
 Sali nixon. Bisulphate of potash. 
 
 Sal prunella. Fused nitrate of potash cast into balls, or cakes. 
 
 Sal volatile. Sesquicarbonate of ammonia. 
 
 Salt of lemons. Citric acid. 
 
 Salt of saturn. Acetate of lead. 
 
 Salt of soda. Carbonate of soda. 
 
 Salt of sorrel. Binoxalate of potash. 
 
 Salt of tartar. Carbonate of potash. 
 
 Salt of vitriol. Sulphate of zinc. 
 
 Salt perlate. Phosphate of soda. 
 
 Saltpetre. Nitrate of potash. 
 
 Salt sedative. Boracic acid. 
 
 Salts of tin. Crystallized protochloride of tin. 
 
 Salt cake. Sulphate of soda. 
 
 Saxon blue. Sulphate of indigo. 
 
 Scalding. Extracting a coloring matter by boiling water. 
 
 Smalt blue. Ground glass, made of alumina, silica, potash, or soda, 
 
 colored blue by oxide of cobalt. 
 Slaked lime. Hydrate of lime. 
 Sludge. Sediment of the blue vat. 
 Single muriate of tin. Protochloride of tin. 
 Sour. Water made acid by sulphuric acid. 
 Soda ash. Carbonate of soda. 
 Spirits. Solutions of chlorides of tin. 
 Spirits of salt. Hydrochloric acid. 
 Spirits of hartshorn. Ammonia. 
 Spirits of wine. Alcohol. 
 Spent. Exhausted of color. 
 Stoveing. Hanging goods in the stove to dry. 
 
 Stock tab. Vessel filled with strong solution of a substance to be kept 
 for use. 
 
 Sugar of lead. Acetate of lead. 
 26 
 
402 
 
 GLOSSARY. 
 
 Substantive color. A color fixed in the fibre without base or com- 
 pound. 
 
 Supertartrate of potash. See argol. 
 
 Sweeten. To pour water upon goods, from a sour, as a partial wash. 
 
 Tartar. See argol. 
 
 Test blue. Sulphate of indigo. 
 
 Tincal. Borate of soda, borax. 
 
 TumbulVs blue. Ferrocyanide of iron, Prussian blue. 
 
 Vegetable alkali. Potash. 
 
 Verdigris. Acetate of copper. 
 
 Verditer. Acetate of copper. 
 
 Vinegar. Acetic acid. 
 
 Vitriol. Sulphuric acid. 
 
 Volatile alkali. Ammonia. 
 
 White vitriol. Sulphate of zinc. 
 
 White copperas. Sulphate of zinc. 
 
 White lead. Carbonate of lead. 
 
 Whiting Carbonate of lime. 
 
 White zinc, Oxide of zinc. 
 
 ERRATA. 
 
 On Page 386, twentieth line from top, for 'picric read phenic. 
 On Page 46, fourth line from top, for cynogen read cyanogen. 
 
 I 
 
INDEX. 
 
 Abstracting tannin from galls, 242 
 
 Acacia catechu, 254 
 
 Acetate of alumina, 141, 227 
 
 of barytes, 135 
 
 of copper, 169, 228 
 
 of iron, 157 
 
 of iron and alumina, 227 
 
 of lead, 171 
 
 of tin, 183 
 Acetic acid combines with copper, 169 
 
 acid, composition of, 236 
 Acid, anilic, 279, 282 
 
 antimonic, 199, 200 
 
 binitro-naphthylic, 387 
 
 boracic, 106 
 
 bromic, 105 
 
 carboazotic, 386 
 
 carbazotic, 280 
 
 carbolic, 375 
 
 carbonic, 108 
 
 chloric, 70 
 
 chloroxynaphthalic, 387 
 
 chromic, 185 
 
 citric, for printing, 146 
 
 colors from carbolic or phenic, 385 
 
 compounds, 236 
 
 ferro-prussic, 119 
 
 fluosilicic, 105 
 
 gallic, 242 
 
 gallic, small quantity in vegetables, 
 243 
 
 hydrobromic, 105 
 hydrofluoric, 105 
 hydriodic, 104 
 hydrochloric, 70 
 hydrocyanic, 110 
 hypochloric, 69 
 hypochlorous, 69 
 hyposulphuric, 101 
 hyposulphurous, 100 
 indigotic, 279, 282 
 isatinic, 280, 282 
 isopurpuric, 386 
 iodic, 104 
 luteo-gallic, 249 
 molybdic, 195 
 
 Acid — 
 
 muriatic, 70 
 nitric, 61 
 nitrous, 61 
 oxalic, 109 
 oxymuriatic, 68 
 picric, 280, 386 
 pyroligneous, 144 
 silicic, 106 
 stannic, 180 
 sulphindylic, 283 
 sulpho- purpuric, 283 
 sulphuric, 95 
 sulphurous, 94 
 tannic, 242 
 telluric, 196 
 tellurous, 196 
 trinitrophenic, 386 
 tungstic, 194 
 valerianic, 279, 282 
 vanadic, 193 
 uric, dye from, 372 
 yellow, 190 
 
 action on Brazil wood, 316 
 Acids, effect on catechu, 255 
 
 of arsenic, 197 
 
 of coal-tar, 374 
 
 of phosphorus, 103 
 
 prevent fermentation in galls, 246 
 
 madder, 339 
 Acorns, cups of, 258 
 Act against use of logwood, 306 
 Actino-chemistry, 28 
 Action of agents upon annotta, 350 
 
 of alumina salts on others, 148 
 
 of bases upon colors, 218 
 
 of catechu in dyeing, 256 
 
 of chemicals on hematoxylin, 308 
 
 of chemicals on indigo, 277 
 
 of metallic salts on galls or su- 
 mach, 246 
 
 of light on nitric acid, 63 
 
 of mordants, 228 
 Adjective colors, 220 
 Adulteration in indigo, 273 
 
 of catechu, 25b" 
 
404 
 
 INDEX. 
 
 Adulteration — 
 
 of cochineal, 369 
 
 of litharge, 170 
 
 of silk, 395 
 Adulterations in indigo extract, 286 
 
 of annotta, 351 
 
 of soap, 132 
 
 of madder, 336, 346 
 Affinity, 41 
 
 elective, in dyeing, 324 
 
 for coal-tar colors, 389 
 
 for dyes, 214 
 
 of cochineal, 369 
 Africa, iudigoes from, 276 
 Agates, 106 
 Agnelet process, 396 
 Air, oxygen in, 47 
 Albumen as a mordant, 390 
 Alcohol as a solvent for aniline, 388 
 
 composition of, 236 
 
 with barwood, 318 
 Aldehyd green, 383 
 Algaroba liquor, 359 
 Alizarin, 337 
 
 attraction of phosphates for, 338 
 
 extraction of, 337 
 
 naphthaline of, 387 
 
 reaction of, 337 
 Alizarine, 345 • 
 
 impure, 343 
 Alkalies, action on Brazil wood, 316 
 
 action on indigo, 277 
 
 contain nitrogen, 236 
 
 effect on catechu, 255 
 Alkalimeter, 82 
 Alkaline earths, 137 
 
 permanganates, 396 
 
 salts of lead for dyeing, 173 
 
 sulphites for printing, 397 
 Alkaloids of coal-tar, 374 
 Alkanet, reactions of, 352 
 
 root, 352 
 Alloy with zinc, 164 
 Alloys, 112 
 Alloxane, 372 
 
 action on fibres, 213 
 Aloes, 363 
 
 as a dye, 363 
 
 patent for preparing, 363 
 Alsace madder, 335 
 Alterants, 217 
 Alum, 137 
 
 as a mordant, 228 
 
 cake, 141 
 
 best mordant for Brazil wood, 317 
 mordants, 145 
 ore, 138 
 shale, 138 
 stone, 138 
 Alumina, 137, 148 
 
 Alumina — 
 
 acetate of, 141, 227 
 detected in copperas, 156 
 detection of, 148 
 mordant, 215 
 
 mordants with cochineal, 369 
 
 salts of, 148 
 
 subacetate of, 147 
 Aluminous lake, 354 
 Aluminate of soda, 141 
 Amalgam of gold, 205 
 
 of silver, 203 
 Amber from acetate of lead, 172 
 
 from chrome, 190 
 America, indigoes from, 276 
 Ammonia, 67 
 
 alum, 139 
 
 chloroxynaphthalate of, 387 
 
 in atmosphere, 62 
 
 isopurpurate of, 386 
 
 purpurate of, 371 
 Analogies of blues, 309 
 Analysis of catechu, 255, 256, 258 
 
 of cochineal, 366 
 
 of flax, 211 
 
 of morindine, 356 
 
 of Neapolitan silk, 222 
 Anderson on sooranjee, 355 
 Anil, 375 
 
 Anilic acid, 279, 282 
 Aniline, 375 
 
 black on wool, 396 
 
 black, printing paste for 397 
 
 blacks, solvent for, 396 
 
 blacks and grays, 384 
 
 blue, 379 
 
 blues and violets, 381 
 brown, 387 
 
 browns and maroons, 385 
 colors, 373 
 
 colors, coloring power and nature 
 of, 391 
 
 colors, identification of, 392 
 colors, determination of, 391 
 colors, Pohl's method of identify- 
 ing, 392 
 colors, steaming, 390 
 colors, value of, 391 
 green printing, 397 
 greens, 383 
 
 greens, Koechlin on, 397 
 orange, 382 
 reds, 380 
 
 to purify indigo, 397 
 violet, 379 
 yellows, 382 
 Animal charcoal in dyeing, 230 
 fibres, gray for, 397 
 fibres, affinity for coal-tar colors, 
 389 
 
INDEX. 
 
 405 
 
 Animal — 
 
 matters used in dyeing, 365 
 Animals, oxygen in, 47 
 Animalization, 390 
 Animalizing cotton, 222 
 Annotta, 348 
 
 adulterations of, 351 
 
 Carribee's preparation of, 349 
 
 colors from, 350 
 
 extraction of, 349 
 
 ingredients of, 349 
 
 John's examination of, 349 
 
 nankeen dye from, 351 
 
 reaction with, 350, 351 
 
 tests for, 351 
 
 to color butter and cheese, 351 
 Anthon's method of valuing cochineal, 
 367 
 
 Antidote for arsenic, 197 
 Antimonic acid, 199 
 Antimony, 199 
 
 Antoine's experiments with galls, 244 
 
 Anyle, 278 
 
 Appendix, 395 
 
 Application of affinity, 42 
 
 Aqua regia, 130 
 
 Archil, 352 
 
 effect of lime upon, 224 
 
 mordants not required for, 353 
 
 preparing, 352 
 
 reaction with, 353 
 
 reds from, 353 
 Army cloth, how dyed, 301 
 Arnotto, 348 
 
 Arrangement of colors, 31 
 Arseniate, and arsenite of copper, 169 
 Arsenic, 196 
 Arsenic acicl, 197, 198 
 
 sages, 197 
 Ash, 113 
 
 Asia, indigoes from, 275 
 Astringents important in dyeing, 221 
 Astringent nature of plants, 241 
 Attraction between fibre and coloring 
 
 matter, 332 
 Autumn, cause of change in plants, 239 
 Avignon madder, 335 
 Azaleine, 380 
 Azote, 59 
 Azuline, 386 
 Azurine, 383 
 
 Bachelier uses lime and casein, 223 
 Ball-soda, 124 
 Bancroft on lac, 370 
 
 on aloes as a dye, 363 
 Bancroft's arrangement of colors, 220 
 
 use of quercitron, 323 
 Bansdorff's theory for varieties of 
 copperas, 154 
 
 Barbary root, 364 
 Solly on, 364 
 Barium, 134 
 Bark, 323 * 
 Barks for dyeing, 258 
 Barreswil on reaction of iron and tan- 
 nin, 251 
 Barwood, 317 
 
 spirits, 183, 225 
 Barytes, 134 
 Bases, 112 
 
 action upon colors, 218 
 
 as mordants, 215 
 
 contain nitrogen, 236 
 
 from aniline, 378 
 Basic salts of lead, 171, 172 
 Bath for dyeing cotton on silk, 384 
 Bechamp on making aniline, 376 
 Beeswax, composition of, 236 
 Bengal catechu, 255 
 
 indigoes, 275 
 Benzole, 375 
 
 Berthollet on greens, 237 
 
 on indigo fermentation, 263 
 on tin as a mordant, 176 
 
 Berthollet's experiments, 77 
 
 Berzelius on impurities in indigo, 266 
 on reaction of iron and tannin, 251 
 process of selecting indigo, 266 
 
 Bichloride of platinum, 207 
 
 of tin, action on fibres, 213 
 
 Bichlorisatin, 281, 282 
 
 Bichromate of potash, 188 
 
 of potash, action of light on, 30 
 of potash, as a mordant, 228 
 of potash, in dyeing, 282 
 of potash, tests for, 193 
 
 Bignonia chica, 359 
 
 Binitro-naphthylic acid, 387 
 
 Binoxalate of potash, 118 
 
 Binoxide of hydrogen, 58 
 of nitrogen, 60 
 of tungsten, 194 
 
 Biphosphate of potash, 118 
 
 "Birmingham, sulphate of copper pro- 
 duced in, 168 
 
 Bismuth, 174 
 
 Bisulphate of iron, 155 
 of potash, 117 
 
 Bisulphuret of iron, 154 
 
 Bisulphuretted hydrogen, 102 
 
 Bitartrate of potash as a mordant, 228 
 
 Bixa orellana, 348 
 
 Bixeine, 351 
 
 Bixine, 351 
 
 Blacks, aniline, on wool, 396 
 Black ash, 114 
 Blacks, aniline, 384 
 Black, best dyed with pyrolignite of 
 iron, 157 
 
406 
 
 INDEX. 
 
 Black- 
 dyeing with sumach, 250 
 flux, 113 
 
 from naphthaline, 387 
 from fustic, 322 
 iron liquor, 227 
 jack, 164 
 lead, 107 
 
 printing paste for aniline, 397 
 
 soap, 132 
 
 tannin superior for dyeing, 246 
 Blauholz, 306 
 Bleaching, 75 
 
 calicoes, improvement in, 398 
 
 cotton goods, 398 
 
 liquor, 80 
 
 of feathers, 396 
 
 powder, 80 
 
 powder to make peroxide of lead, 
 171 
 
 powder, value of, 81 
 
 with cobalt, 163 
 
 with sulphurous acid, 94 
 Blende, 164 
 Bleu de nuit, 381 
 
 lumiere, 382 
 Block tin, 176 
 Blue, analogies of, 309 
 
 china, 283 
 
 color from alumina, 148 
 
 coloring matters, composition of, 
 
 309 
 
 crust on lead, 170 * 
 dyeing, 121 
 
 dyeing silks and woollens, 286 
 
 for porcelain and glass, 162 
 
 from red flowers, 240 
 
 ground, white pattern on, 282 
 
 iron and tin for, 227 
 
 Prussian, from nitrate of iron, 159 
 Blues, aniline, 381 
 
 from naphthaline, 387 
 
 indigo, composition of, 309 
 
 mordant for, 228 
 
 soluble, 389 
 Blue-stone, 168 
 
 sages, 169 
 Blue vat, how made, 288 
 
 vitriol, 168 
 Boiling lye, 85 
 
 of liquids, 21 
 Bois bleu, 306 
 
 de campeche, 306 
 
 de pernambouc, 314 
 Bolley's method of testing indigo, 273 
 Bolley on quercitron, 324 
 Bombay catechu, 255 
 Bombix, 212 
 
 Bones colored by madder, 338 
 Boracic acid, 106 
 
 Borate of soda, 106, 130, 
 Borax, 106 
 Boron, 106 
 
 Bottom, definition of, 250 
 Braconnot on casein, 223 
 Brasileto, 314 
 Brass, 112, 164 
 
 Brazil dye, action of metals on, 316 
 
 Brazil, indigoes of, 276 
 
 wood, action of acids on, 316 
 wood, action of alkalies on, 316 
 woods, 314 
 
 Brazilienholz, 314 
 
 Brezilin, 315 
 
 Brezilein, 316 
 
 Brezilin, composition of, 316 
 British barilla, 124 
 Bromates, 105 
 Bromic acid, 105 
 Bromine, 105 
 Brown, aniline, 387 
 
 from manganese, 150 
 Browning, 225 
 Brown, Jacobsen's, 387. 
 
 madder, 339 
 
 maroon, de Laire's, 385 
 
 picric acid, 387 
 Browns, aniline, 385 
 Brown sugar of dyers, 172 
 
 upon yarns from bark, 324 
 Broquette uses casein as a mordant, 
 
 222 
 Bucking, 76 
 
 Buff, from nitrate of iron, 159 
 Butter colored with annotta, 351 
 
 Cabbage affected by light, 238 
 Cadmium, 166 
 Cxsalpina brasileta, 314 
 
 cresta, 314 
 Calamine, 164 
 
 Calcareous waters for madder, 348 
 Calcium, 135 
 
 Calico printing with coal-tar colors, 390 
 Calorific rays, 25 
 Calvert's green, 383 
 Campeachy wood, 306 
 Camwood, 320 
 Cannabis saliva, 212 
 Caoutchouc, composition of, 236 
 Carbazotic acid, 280 
 Caraccas indigoes, 276 
 Carajuru, 358 
 Carboazotic acid, 386 
 Carbolic acid, 375 
 acid colors, 385 
 
 or phenic acid, colors from, 385 
 Carbon, 106 
 Carbonated alkali, 114 
 Carburetted hydrogen, 111 
 
INDEX. 
 
 407 
 
 Carbonate of iron, 157 
 
 of lead, 171 
 
 of lime, 136 
 
 of nickel, 164 
 
 of soda, 124 
 Carbonates of lime, 135 
 Carbonic acid, 108 
 
 decomposed by light, 29 
 
 oxide, 108 
 Carmine, 366, 369 
 
 of indigo, 305 
 
 reaction with, 366 
 Carolina indigoes, 276 
 Carribees' preparation of annotta, 349 
 Carthamus, 329 
 Carthamine, 329 
 Carucuru, 359 
 
 Carves and Thirault, mureine grays, 38 
 
 Caseate of lime, 223 
 
 Casein as a mordant, 222, 396 
 
 Castelhaz's mauveine gray, 385 
 
 Catalysis, 43 
 
 Catalytic influence, 43 
 
 Catechu, 254 
 
 action in dyeing. 256 
 
 adulteration of. 256 
 
 impurities in, 256 
 
 Malabar, 256 
 
 reactions of, 257 
 
 spurious, 256 
 Caustic lime, 135 
 
 potash, 116 
 
 potassa, action on fibres, 213 
 
 soda, 124 
 Celery affected by light, 238 
 Cerium, 201 
 Cerulin, 283 
 
 Chalk necessary sometimes in water 
 248 
 
 Chameleon, mineral, 150 
 Change in hues in leaves, 239 
 Characteristics of indigo, 277 
 Charcoal, 107 
 Charcoal in dyeing, 230 
 Cheese colored with annotta, 351 
 Chemic, 80, 283, 285 
 Chemical affinity, 41 
 
 changes in making indigo, 263 
 composition of indigo, 277 
 effects of heat upon colors, 23 
 investigation of logwood, 309 
 names, 399 
 nomenclature, 37 
 rays, 25 
 
 Chemistry necessary in dyeing, 216, 
 248 
 
 Chevalier, reports on exposition, 395 
 Chevreul on fustic, 321 
 
 on indigoes, 274 
 
 on quercitron, 324 
 
 Chevreul — 
 
 on reaction of iron and tannin, 251 
 Chevreul's analysis of pastel, 294 
 
 examination of logwood, 306 
 
 experiments, 232 
 
 process for Brazil wood, 315 
 
 process of selecting indigo, 266 
 
 process to obtain coloring matter 
 from logwood, 307 
 Chica, 358 
 China, blue, 283 
 Chlorate of potash, 118 
 Chloric acid, 70 
 Chloride of antimony, 199 
 
 of barium, 134 
 
 of cadmium, 166 
 
 of calcium, 136 
 
 of chromium, 186 
 
 of copper, 168 
 
 of gold, 206 
 
 of iron, 157 
 
 of lead, 173 
 
 of lime, 80 
 
 of manganese, 150 
 
 of nickel, 164 
 
 of nitrogen, 74 
 
 of palladium, 208 
 
 of platinum, 207 
 
 of silver, 203 
 
 of silver, effect of light on, 29 
 of sodium, 124, 130 
 of strontium, 135 
 of tin, 177 
 
 of tin as a mordant, 228 
 
 of zinc, 165 
 Chlorides, 71 
 
 of iridium, 209 
 
 of osmium, 209 
 Chlorimeter, 87 
 Chlorimetry, 86 
 Chlorindoptin, 281, 282 
 Chlorine, 68 
 
 acting on indigo, 281 
 
 bleaching, 78 
 
 effect of light on, 28 
 
 process, Lightfoot's, 396 
 Chlorisatin, 281, 282 
 Chloroform as a solvent of indigo, 397 
 Chloronile, 281, 282 
 Chlorophyllite, 237 
 Chloroxynaphthalate of ammonia, 387 
 Chloroxynaphthalic acid, 387 
 Chocolate from morindine, 357 
 Choice of mordants, 215 
 Chromate of copper, action of light on, 
 30 
 
 of lead, 189 
 
 of lead as a mordant, 397 
 Chromates of potash, 187 
 Chrome as a mordant, 192 
 
408 
 
 INDEX. 
 
 Chrome — 
 
 colors affected by light, 30 
 
 green, 191 
 
 iron, 185 
 
 orange, 191 
 
 yellow, 189 
 
 yellow dye, 189 
 
 yellows, dyeing of, 165 
 Chromic acid. 185, 187 
 
 acid, action on indigo, 280 
 Chromium, 185 • 
 
 salts of, 193 
 Chrysaniline, 379, 381 
 
 yellow, 382 
 Chryso-rhamnine, 328 
 Chrystoluidine, 379, 381 
 
 yellows, 382 
 Circumstances influencing affinity, 42 
 Cinnabar, 202 
 
 Citric acid, composition of, 236 
 
 for printing, 146 
 C. Koechlin's experiment, 384 
 Clay iron stone, 151 
 Clift's green, 383 
 Cloves, composition of oil, 236 
 Coal, 107 
 
 gas, 111 
 
 pit, tansy growing in, 238 
 
 tar, acids of, 374 
 
 tar, alkaloids of, 374 
 
 tar colors, dyeing with, 389 
 
 tar colors, general remarks on, 388 
 
 tar, composition of, 373 
 
 tar, distillation of, 374 
 
 tar, dyes from, 374 
 
 tar, neutral substances of, 374 
 Cobalt, 162 
 
 nitrate of, effect on alumina, 148 
 Coccus, 371 
 
 cacti, 365 
 
 ficus, 370 
 
 loco, 370 
 Cochineal, 365 
 
 adulteration of, 369 
 
 affinity of, 369 
 
 alumina mordants with, 369 
 
 analysis of, 366 
 
 Anthon's method of valuing, 367 
 German experiments on, 369 
 Robiquet's method of valuing, 367 
 wild, 366 
 value of, 367 
 
 Coke, 107 
 
 Colorimeter, 336 
 
 Colorine, 340, 343 
 
 Coloring matters, madder, 338 
 hypotheses on, 234 
 power and nature of aniline colors, 
 391 
 
 principles of madder, 344 
 
 Colors, action of bases upon, 218 
 absorbed by charcoal, 107 
 adjective, 220 
 
 Bancroft's arrangement of, 220 
 contrast of, 31 
 effect of heat on, 23 
 fast, 221 
 fugitive, 221 
 of flowers, 240 
 from annotta, 350 
 from carbolic or phenic acid, 385 
 from coal tar, 373 
 from naphthaline, 387 
 from vegetables, cause of, 237 
 from wongshy, 362 
 saddened, 247 
 simple, 26 
 substantive, 220 
 Combustion, oxygen a supporter of, 
 49 
 
 with tin and copper, 168 
 Commercial alizarine, 346 
 
 indigoes, 274 
 Common iron ores, 151 
 Complementary colors, 31 
 Composition of blue coloring matters, 
 309 
 
 of brezilin, &c, 316 
 
 of catechu, 255, 256, 258 
 
 of coal tar, 373 
 
 of products of indigo and nitric 
 acid and chlorine, 282 
 
 of quercitrine, 324 
 
 of sandal wood, 317 
 
 of vegetable substances, 235 
 
 of white indigo, 278 
 Compositions of the copperas vat, 305 
 Compounds, rules for naming, 37 
 Conditions of matter, 18 
 Constitution of salts, 44 
 Contrast of colors, 31 
 Copper, 167 
 
 acetate of, 228 
 
 arsenite of, 197 
 Copperas, 155, 156 
 
 effect of light on, 30 
 
 preferable as a mordant, 159 
 
 vats, 305 
 
 white, 165 
 Copper boilers lined with tin, 177 
 
 detected in copperas, 156 
 
 effect of salts, on catechu, 255 
 Coralline, 386 
 
 Cordillot's experiments, 384 
 Cornwall, tin mines of, 176 
 Coromandel indigoes, 275 
 Corrosive sublimate, 202 
 Cotton, 211 
 
 animalizing, 222 
 
 dyeing with manganese, 150 
 
INDEX. 
 
 409 
 
 Cotton — 
 
 goods, bleaching of, 398 
 
 mordant for, 228 
 
 tests for, 213 
 Crajuru, 359 
 
 Cream of tartar as a mordant, 228 
 Creosote, 375 
 Crofting, 76 
 
 theory of, 77 
 Cropped madder, 334 
 Crude naphtha, 375 
 Crum, composition of indigo, 277 
 
 on indigo with sulphuric acid, 284 
 
 on testing indigo, 268 
 Crura' s chlorimeter, 87 
 
 method of chlorimetry, 86 
 Cubic nitre, 130 
 Cudbear, 352 
 Cupeilation of lead, 170 
 Cupro-ammoniacal liquor, action on 
 
 fibres, 213 
 Cups of acorns, 258 
 Curcuma longa, 328 
 Curcumine, 328 
 
 Curd of milk as a mordant, 396 
 
 Cyanate of potash, 123 
 
 Cyanides, 110 
 
 Cyanogen, 110 
 
 Cyanogen, 46 
 
 Cyanide of potassium, 123 
 
 Cynips, 242 
 
 Dampness produced by chloride of zinc, 
 165 
 
 Dana's process of selecting indigo, 267 
 Danger from arsenic, 197 
 
 from arsenites of copper, 169 
 Davy on galls, 242 
 Dead cotton, 211 
 
 . oil, 374 
 Drebbel's discovery of value of tin as a 
 
 mordant, 176 
 Decaisne on madder, 344 
 Deception in galls, 249 
 Decoction, of Brazil wood, 316 
 Decoctions of logwood, 310 
 Decoctions, preparation of, 311 
 Decolorizing indigo as a test, 273, 274 
 Decomposition of gallic acid, 243 
 Defects in indigoes, 276 
 De Laire's brown maroon, 385 
 Deoxygenated indigo, 264 
 Dephlogisticated muriatic acid, 68 
 Depouilly process, 396 
 Detection of alumina, 148 
 
 of cobalt, 163 
 
 of impurities in litharge, 170 
 in sulphate of copper, 168 
 Determination of aniline colors, 391 
 of value of bleaching powder, 81 
 
 Detonation of isopurpurates, 336 
 Detonating qualities of picric acid, 280 
 Deutoxide of tin, 178 
 Dextrine in sizing warps, 398 
 Diagram of colors, 32 
 Diamond, 107 
 Didymium, 210 
 
 Difference in quality of red liquor, 145 
 Differences between an element and 
 
 compound, 34 
 Dingier on decoctions of Brazil wood, 
 
 326 
 
 Dinoxide of copper, 167 
 Diphenylic rosaniline, 379 
 Dissolving salts, 55 
 Distillation of coal tar, 374 
 
 of water, 51 
 Divi divi, 258 
 Doctored logwood, 311 
 Double muriates of tin, 181 
 Dumas, composition of indigo, 277 
 
 on indigoes, 274 
 
 on sulph-indylic acid, 238 
 
 plan to test soap, 133 
 
 process for indigo, 397 
 
 theory for varieties of copperas, 154 
 
 theory of composition of white 
 indigo, 278 
 
 theory of mordants, 228 
 Dung substitute, 103 
 Dutch madder, 334 
 Dye from uric acid, 372 
 Dye-houses, vats in, 291 
 Dyeing affected by quality of water, 
 247 
 
 black with sumach, 250 
 
 chemistry necessary in, 216 
 
 Prussian blue, 120 
 
 silks and woollens blue, 286 
 
 study necessary in, 233 
 
 temperature for, 390 
 
 with barwood, 319 
 
 with coal tar colors, 389 
 
 without mordants, 395 
 
 with safflower, 330 
 
 with woad and pastel, 292 
 
 with wongshy, 361 
 Dyes from coal tar, 374 
 Dye-woods, tannin in, 259 
 
 Earth, oxygen in, 47 
 
 Earths proper, 137 
 
 East Indian galls, 248 
 
 Effects of different rays upon colors, 27 
 
 of light causing combination, 28 
 Effect of nitrate of cobalt on alumina, 
 148 
 
 Egypt, indigo of, 276 
 Elective affinity in dyeing, 324 
 Electricity in mordanted goods, 146 
 
410 
 
 INDEX. 
 
 Elementary substances, 47 
 Elements of matter, 34 
 
 of vegetable substances, 234 
 Embroideries, imitation of, 396 
 Emeraldine, 383 
 Emetic tartar, 200 
 England, indigo prohibited in, 260 
 English copperas best, 156 
 Epsom salt, 136 
 Erbium, 210 
 
 Erdmann collects and names haematein 
 308 
 
 Erdmann's process to obtain coloring 
 
 matter from logwood, 307 
 Error in selecting copperas, 155 
 Erythrozym, 344 
 Essential salt of lemons, 118 
 Evil spirit of the mines, 162 
 Experiments on gases from indigo, 263 
 
 on reaction of iron and tannin, 252 
 
 with flowers, 240 
 Explosive nature of picrates, 386 
 Exposition, reports on, 395 
 Extracting alizarin, 337 
 
 coloring matter of indigo, 261 
 Extraction of annotta, 349 
 
 of gold from ore, 205 
 
 of iron from ore, 151 
 
 of silver from ore, 203 
 Extract of indigo, 283, 285 
 
 of logwood, 307, 308 
 
 of safflower, 332 
 Extracts of woods, 326 
 
 Fabric, relation of colors to, 26 
 
 Fabrics, textile, 211 
 
 Fancy shade, to dye, 75 
 
 Fast colors, 221 
 
 Feather bleaching, 396 
 
 Fermentation injures gall-dyes, 243 
 
 Ferricyanide of potassium, 122 
 
 Ferrocyanide of potassium, 119 
 
 Ferrocyanides, 120 
 
 Ferro-prussic acid, 119 
 
 Fibres, action of alloxane on, 213 
 
 bichloride of tin on, 213 
 
 caustic potassa, 213 
 
 cupro-ammoniacal liquors on, 
 213 
 
 muriatic acid on, 213 
 nitric acid on, 213 
 Fire-proof fabrics, 194 
 Firing, 226 
 Fixed green, 383 
 Flavine, 325 
 Flax, 211 
 
 tests for, 213 
 Flints, 106 
 
 Flowers, coloring matters of, 240 
 of madder, 346 
 
 Flowers — 
 
 of sulphur, 94 
 Fluorine, 105 
 Fluor spar, 105 
 Fluosilicic acid, 105 
 Fraud in galls, 249 
 Fremy's third oxide of iron, 151 
 French purple, 354 
 Fuchsine, 380 
 Fugitive colors, 221 
 
 nature of gallates, 243 
 Fuming sulphuric acid, 96 
 Furs, 212 
 Fusteric, 323 
 Fustet, 322 
 Fustic, 321 
 
 young, 322 
 
 Gallic acid, 242 
 
 composition of, 236 
 
 decomposition of, 243 
 
 not largely in vegetables, 243 
 Galls, 241 
 
 Aleppo, 248 
 
 analysis of, 249 
 
 Antoine's experiments with, 244 
 best, 248 
 black, 248 
 choice of, 248 
 green, 248 
 
 Guibourt's analysis of, 249 
 
 kinds of, 248 
 
 loss of color from, 243 
 
 markets for, 248 
 
 marmorated, 248 
 
 mixed, 248 
 
 natural, 248 
 
 selecting, 248 
 
 varieties of, 248 
 
 white, 248 
 Gall-nuts, 248 
 Gall-wasp, 242 
 
 Galvanic action in boilers, 177 
 Garancine, 340 
 
 patent for, 341 
 
 reactions with, 343 
 Gases absorbed by charcoal, 107 
 
 formed in making indigo, 263 
 
 solution of, 57 
 Gelatine as a mordant, 390 
 General effects of heat, 19 
 Generalities on textile fabrics, 213 
 General properties of matter, 18 
 
 remarks on coal-tar colors, 388 
 German experiments on cochineal, 369 
 
 silver, 112, 163 
 
 vat, 300 
 Girardin on barwood, 317 
 Girard and De Laire's purple, 381 
 Glauber salts, 129 
 
INDEX. 
 
 411 
 
 Gluten, 266 
 Glossary, 399 
 Gold, 205 
 Gossypiuru, 211 
 Grain tin, 176 
 Graphite, 107 
 
 Gray for animal fibres, 397 
 
 mauveine, 385 
 Grays, aniline, 384, 385 
 
 mureine, 385 
 Greeks early used indigo, 260 
 Green a compound color, 237 
 
 alizarine, 345 
 
 chrome, 191 
 
 fast, Williams' discovery of, 327 
 from arsenic, 197 
 from fustic, 322 
 
 fruits, excess of oxygen in, 236 
 
 picric acid, 386 
 
 printing aniline, 397 
 
 Scheele's, 169 
 
 vitriol, 152 
 Greens, aniline, 383 
 
 dyeing by chemic, 237 
 
 picric acid, 386 
 Guatimala indigoes, 276 
 Gum and sugar same in composition, 
 235 
 
 Gutta percha to prevent sores from 
 
 chrome and lead, 193 
 Gypsum, necessary sometimes in water, 
 
 248 
 
 Hsematein, 308 
 Hoematine, 306 
 Hematoxylin, 306 
 Hxmatoxylon campeachiacum, 306 
 Hard water, 52 
 Harmonizing colors, 32 
 Hartshorn, 67 
 
 Hausm arm's experiment, 223 
 Heat, 18 
 
 effect on colors, 23 
 
 the cause of conditions of matter, 
 18 
 
 Heavy oil, 374 
 Heavy spar, 134 
 Hemp, 212 
 
 Hindoo method of using morinda, 357 
 H. Kcechlin on aniline greens, 397 
 XL Koechlin's leucaniline brown, 385 
 Hofmann's blues and violets, 382 
 Hunter on morinda, 357 
 Hunt's experiments with vegetables, 
 238 
 
 Husks of nuts for dyeing, 259 
 Hydrated ether with barwood, 319 
 Hydrate of lime, 135 
 Hydrated protoxide of anyle, 278 
 Hydrates, 40 
 
 Hydriodic acid, 104 
 Hydrobromic acid, 105 
 Hydrocarbons, 111 
 Hydrochlorate of ammonia, 67 
 Hydrochloric acid, 70 
 Hydrocyanic acid, 110 
 Hydrofluoric acid, 105 
 Hydrotluosilicic acid, 106 
 Hydrogen, 49 
 
 arseniureted, 199 
 
 binoxide of, 58 
 
 favors formation of sugar, 236 
 Hydrogenation of indigo, 300 
 Hydrometer, 64, 65 
 
 not reliable, 145 
 Hyperchloric acid, 70 
 Hyperoxymuriates, 70 
 Hypochlorates, 70 
 Hypochloric acid, 69 
 Hypochlorous acid, 69 
 Hypophosphorous acid, 103 
 Hyposulphuric acid, 101 
 Hyposulphurous acid, 100 
 Hypothesis on coloring matters, 234 
 
 Ibiripitanga, 314 
 
 Identification of aniline colors, 392 
 
 Imitation of embroideries, 396 
 
 Imperial purple, 381 
 
 Improvement in bleaching calicoes, 398 
 
 Impure alizarine, 343 
 
 Impurities in catechu, 256 
 
 in hydrochloric acid, 72 
 
 in indigo, 265 
 
 in madder, 346 
 
 in nitric acid, 64 
 
 in sulphate of copper, 168 
 
 of water, 52 
 Increase in weight of silk by dyeing, 
 395 
 
 Indian vat, 295, 299 
 
 Indicum, 260 
 
 Indigo, 260 
 
 action of alkalies on, 277 
 action of chemicals on, 277 
 action of chlorine on, 281 
 action of chromic acid on, 280 
 action of nitric acid on, 280 
 action of salts on, 277 
 action of sulphuric acid on, 283 
 action of water on, 277 
 adulteration of, 273 
 Berthollet on fermentation in, 263 
 Berzelius' mode of selecting, 266 
 blue, 292 
 
 blue, composition of, 309 
 
 Bolley's test for, 273 
 
 brown, 266 
 
 characteristics of, 277 
 
 chemical changes in making, 263 
 
INDEX. 
 
 chemical composition of, 277 
 Chevreul's mode of selecting, 266 
 chlorine to test, 273 
 chloroform as a solvent for, 397 
 composition of products of, by nitric 
 
 acid and chlorine, 282 
 Crum's analysis of, 277 
 Crum's test for, 268 
 Dana's mode of selecting, 267 
 decolorizing as a test, 273, 274 
 deoxygenated, 264 
 Dumas' analysis of, 277 
 Dumas' process for, 397 
 early used by Greeks, 260 
 early used by Romans, 260 
 extract, 283, 285 
 
 adulteration of, 286 
 extracting coloring matter of, 261 
 extract of, 283, 285 
 hydrogenation of, 300 
 impurities in, 265 
 Kane on changes in, 263 
 manufacture of, 261 
 nature of, 265 
 Penney's test for, 274 
 prohibited in England, 260 
 properties of pure, 268 
 purification of, 397 
 purifying, 397 
 red, 266 
 
 Reinsh's tests for, 272 
 sampling, 266 
 
 Schlumberger's method for pure, 
 
 269 
 Senegal, 276 
 
 starch used to adulterate, 273 
 sublimation of, 268 
 Taylor's method for pure, 269 
 tests for, 266, 267, 268, 269, 272 
 Thomson on changes in, 263 
 to ascertain quality of, 266 
 to know value of, 266, 267 
 Ure on gases from, 263 
 value of, 271 
 white, 277 
 
 white, composition of, 309 
 white lead used to adulterate, 273 
 with sulphuric acid, 284 
 igoes, Caraccas, 276 
 Carolina, 276 
 Chevreul on, 274 
 commercial, 274 
 defects in, 276 
 Dumas on, 274 
 from Africa, 276 
 from America, 276 
 from Asia, 275 
 from Egypt, 276 
 Guatimala, 276 
 
 Indigoes — 
 
 of Bengal, 275 
 
 of Brazil, 276 
 
 of Coromandel, 275 
 
 of Java, 276 
 
 of Madras, 275 
 
 of Manilla, 275 
 
 of Mexico, 276 
 Indigofera, 260 
 Indigogen, 287 
 Indigotic acid, 279, 282 
 Indisine, 381 
 
 Ingredients of annotta, 349 
 
 Ink, permanent, 204 
 
 Inks, sympathetic, 162 
 
 Intermediate oxides of iron, 254 
 
 Iodic acid, 104 
 
 Iodide of ethyl green, 383 
 
 Iodide of potassium, colors from, 27 
 
 Iodine, 104 
 
 Iodine blues and violets, 382 
 Iridium, 208 
 Iron, 151 
 
 acetate of, 157 
 
 bisulphate of, 155 
 
 bisulphuret of, 154 
 
 carbonate of, 157 
 
 chloride of, 157 
 
 chrome, 185 
 
 deleterious in manganese, 150 
 effect of salts on catechu, 255 
 extracted from sulphate of man- 
 ganese, 150 
 liquor, 157 
 mordant, 215 
 nitrate of, 158 
 nitrate of, to prepare, 227 
 peracetate of, 161 
 peroxalate of, 161 . 
 persalts of, 158 
 persulphate of, 158, 162 
 per tartrate of, 161 
 protosalts, 161 
 pyrites, 154 
 
 pyrolignite of, 157 " 
 sulphate of, 152 
 sulphate of, as a mordant, 228 
 and alumina, acetate of, 227 
 and tin for royal blue, 227 
 
 Isatine, 280, 282 
 
 Isatinic acid, 280, 282 
 
 Isatis tinctoria, 260 
 
 Isomeric bodies, 235 
 
 Isopurpurates, 386 
 
 detonation of, 386 
 
 Isopurpuric acid, 386 
 
 Ivory, black, 107 
 
 Jacobsen's brown, 387 
 Jamaica wood, 306 
 
INDEX. 
 
 413 
 
 Java indigoes, 276 
 Jaune d'or, 387 
 
 John's analysis of cochineal, 366 
 examination of annotta, 349 
 Judging logwood, 312 
 Julian and Roquer introduce flowers of 
 madder, 346 
 
 Kane on changes in indigo, 263 
 Kane's theory of bleaching, 91 
 Kaolin, 141 
 
 Kermes, reactions of, 371 
 Kerms, 371 
 Killed iron, 227 
 Killing iron, 160 
 King's yellow, 198 
 Kobalds, 162 
 
 Koechlin C, bath for dyeing cotton or 
 
 silk, 384 
 Koechlin, C, experiments, 384 
 Koechlin, H., on aniline greens, 397 
 
 leucaniline browns, 385 
 Kopp's production of alizarine, 345 
 Kuhlmann's xanthine, 344 
 
 Lac, 370 
 
 dye, 370 
 
 lac, 370 
 
 spirits, 371 
 Lacs, 371 
 
 Lake, aluminous, 354 
 
 lake, 370 
 Lampblack, 107 
 Lanthanium, 210 
 Laurent on naphthaline, 387 
 Lauth's experiments, 384 
 Lavenders from safnower, 331 
 Lead, 169 
 
 basic salts of, 172 
 
 chromate of, 189 
 
 chromate of as a mordant, 397 
 
 effect of salts on catechu, 255 
 
 salts, value of, 174 
 
 white, to adulterate indigo, 273 
 Leaves absorb oxygen, 239 
 
 why they change in autumn, 239 
 Lemon juice, composition of, 236 
 Lepidolite, 131 
 Leucaniline, 379 
 
 brown, 385 
 Levant madder, 334 
 Libi davi, 258 
 Lichen roccella, 352 
 Liebig on presence of nitrogen, 234 
 
 on reaction of indigo, 278 
 Light, 25 
 
 action of on nitric acid, 63 
 
 affects colors, 29 
 
 changes color of plants, 238 
 
 Light — 
 
 decomposes chemical compounds, 
 29 
 
 Lightfoot's black, 384 
 
 chlorine process, 396 
 Light oil, 374 
 Lilacs, from safflower, 331 
 Lima wood, 315 
 Lime, 135 
 
 chloride of, 80 
 
 in blue vat, 291 
 
 in cl^eing with sumach, 251 
 
 objectionable in using acetate of 
 lead, 172 
 
 and casein as a mordant, 223 
 Limes, quality required, 305 
 Limestone, 136 
 Lime-water, 135 
 
 on logwood, 311 
 Linum usitatissimum, 211 
 Liquids, boiling of, 21 
 Liquor chica, 359 
 Litharge, 170 
 Lithia, 130 
 
 Lithospermum tinctorium, 352 
 
 Lithium, 130 
 
 Localities of tin ore, 176 
 
 Logwood, 306 
 
 chemical investigation of, 309 
 Chevreul's examination of, 306 
 Chevreul's process to obtain the co- 
 loring matter from, 307 
 decoctions, 310 
 
 Parkes on, 311 
 doctored, 311 
 
 Erdmann's process to obtain the 
 
 coloring matter of, 307 
 extract, 307, 308 
 
 forbidden by Queen Elizabeth, 306 
 
 judging, 312 
 
 lime-water on, 311 
 
 reactions on, 309 
 
 scalding, 310 
 
 testing, 312 
 
 value of, 312 
 Lowe's green, 383 
 Luminous rays, 25 
 Lunar caustic, 204 
 Luleo- gallic acid, 249 
 Luteoline, 327 
 Lythrum fruticosum, 357 
 
 MacCulloch, distinction between bar- 
 wood and camwood, 317 
 Madder, 333 
 
 adulterations of, 336, 346 
 
 Alsace, 335 
 
 Avignon, 335 
 
 bones colored by, 338 
 
 brown, 339 
 
414 
 
 INDEX. 
 
 Madder — 
 
 coloring matters, 338 
 coloring principles, 344 
 cropped, 334 
 Decaisne on, 344 
 Dutch, 334 
 
 extract, Pernod and Picard's, 397 
 
 extract, Rochleder's, 397 
 
 extract, Schutzenberger's, 398 
 
 extracts, values of, 397 
 
 flowers of, 346 
 
 Levant, 334 
 
 marks of, 335, 336 
 
 Meissonnier's extracts, 398 
 
 mordants for, 344 
 
 orange, 339 
 
 Pernod's test for, 346 
 
 preparations, 340 
 
 purple, 338 
 
 qualities of, 334 
 
 red, 338 
 
 sampling, 347 
 
 Schutzenberger on, 344 
 
 silk printing with, 346 
 
 tests for, 336 
 
 uncropped, 334 
 
 urine colored by, 338 
 
 useful products of, 339 
 
 varieties of, 334 
 
 yellow, 339 
 Madderic acid, 339 
 Madras indigoes, 275 
 Magenta, 380 
 Magnesia, 136 
 
 in mordanting, 224 
 
 objectionable in limes, 305 
 Magnesia nigra, 149 
 Magnesium, 136 
 Mahogany sawdust, 259 
 Malabar catechu, 256 
 Malvaceso, 211 
 Management of vats, 302 
 Manchester yellow, 387 
 Manganese, 149 
 
 chloride of, 150 
 
 how detected, 151 
 
 oxides of, 149 
 
 sulphate of, 149 
 Mangrove bark, 258 
 Manilla indigoes, 275 
 Manipulations of mordants, 147 
 Manufacture of aniline, 376 
 
 of indigo, 261 
 
 of indigo extract, 285 
 
 of soap, 131 
 Marine acid. 70 
 Marks of madder, 335, 336 
 Mamas' process for French purple, 
 353 
 
 Maroons, aniline, 383 
 
 Martius' yellow, 387 
 Matter, 18 
 Mauvaniline, 381 
 Mauve, 381 
 Mauveine, 379 
 
 gray, 385 
 
 sulphate of, 381 
 Measures of temperature, 19 
 Meissonnier's madder extracts, 398 
 Mellon, 111 
 Mellonides, 111 
 Mercer's experiments, 213 
 Mercury, 202 
 
 Metallic oxides, action on logwood, 309 
 
 salts, action on galls or sumac, 246 
 
 substances, 112 
 Metals, 112 
 
 action on Brazil dye, 316 
 
 proper, 149 
 Method of obtaining tannin from galls 3 
 242 
 
 Mexico, indigoes of, 276 
 Meyer process, 396 
 Mimosa used in dyeing, 357 
 Mineral alkali, 123 
 chameleon, 150 
 Minium, 171 
 Mistic, 366 
 
 Modified pastel vat, 298 
 Molybdenum, 195 
 Molybdic acid, 195 
 Monophenylic rosaniline, 379 
 Mordant, 144 
 
 alum, 228 
 
 alumina, 215 
 
 bitartrate of potash as, 228 
 
 casein as, 396 
 
 chloride of tin as, 228 
 
 chrome as, 192 
 
 copperas as, 159 
 
 cream of tartar as, 228 
 
 for cotton, 228 
 
 for woollens, 228 
 
 iron, 215 
 
 repose after, 229 
 
 Roman alum as, 228 
 
 sulphate of iron as, 228 
 
 test of, 145 
 
 tin, 215 
 
 tin as, 176 
 
 value of alum as, 138 
 Mordanted goods, electricity of, 146 
 Mordants, 214 
 
 action of, 228 
 
 alum, 145 
 
 bases as, 215 
 
 choice of, 215 
 
 Dumas' theory of, 228 
 
 for Brazil wood, 317 
 
 for coal-tar colors, 390 
 
INDEX. 
 
 415 
 
 Mordants — 
 
 for coal tar colors on vegetable 
 fibres, 395 
 
 for madder, 344 
 
 for printing, 224 
 
 manipulations of, 147 
 
 not required for archil, 353 
 
 oxides as, 215 
 
 phenomena from, 146 
 
 properties, 232 
 
 solution of, 215 
 
 theory of, 228 
 Morin, 321 
 
 Morinda citrifolia, 357 
 
 Hindoo method of using, 357 
 
 Hunter on, 357 
 Morindine, analyses of, 356 
 
 chocolate from, 357 
 
 purple from, 357 
 
 solution of, 356 
 31orus tinctoria, 321 
 Mosul galls, 248 
 Mottled soap, 131 
 Mucilaginous compounds, 236 
 Mull, 334 
 Munjeet, 348 
 Mureine grays, 385 
 Murexide, 371 
 
 reactions of, 372 
 Muriates, 71 
 Muriatic acid, 70 
 
 acid, action on fibres, 213 
 Myrobalans, 258 
 
 used in dyeing, 357 
 
 Naming compounds, 37 
 Nankeen dye, Scott's, 351 
 
 from nitrate of iron, 159 
 Naphtha, 375 
 
 crude, 375 
 
 solvent, 375 
 Naphthalamine, 387 
 Naphthaline, 375 
 
 alizarin from, 387 
 
 colors from, 387 
 
 Laurent on, 387 
 Naphthylamine, 387 
 
 yellow, 387 
 Native ores of arsenic, 198 
 Nature of indigo, 265 
 
 of light, 25 
 
 of salt, 39 
 Neapolitan silk, analysis of, 222 
 Nerium Tinctorium, 260 
 Neutral substances of coal tar, 374 
 New vegetable dyes, 355 
 Nicaragua wood, 315 
 Nicholson's purple, 381 
 Nickel, 163 
 
 carbonate of, 164 
 
 Nickel — 
 
 chloride of, 164 
 
 nitrate of, 164, 
 
 sulphate of, 164, 
 Night blue, 382 
 
 green, 383 
 Niobium, 210 
 Nitrate of ammonia, 62 
 
 of barytes, 134 
 
 of bismuth, 175 
 
 of cobalt, effect in alumina, 148 
 
 of copper, 168 
 of iron, 158 
 
 of iron, to prepare, 227 
 
 of lead, 171 
 
 of nickel, 164 
 
 of potash, 62, 118 
 
 of silver, 204 
 
 of silver, effect of light on, 29 
 
 of soda, 62, 124, 130 
 
 of strontium, 135 
 
 of tin, 178 
 
 of zinc, 165 
 Nitrates, action on Brazil dye, 316 
 
 deposits of, 62 
 Nitre, 64 
 Nitric acid, 61 
 
 acid, effect of light on, 29 
 
 acid, action on fibres, 213 
 
 acid, action on indigo, 280 
 
 acid, in dyeing, 225 
 Nitrogen, 58 
 
 chloride of, 74 
 
 not in coloring matters, 235 
 Nitromuriate of tin, 225 
 Nitrous acid, 61 
 Nomenclature, 37 
 Nordhausen acid, 96 
 Normandy on soap, 133 
 Nuts, gall, 248 
 
 valonia, 258 * 
 
 Oak bark, 258 
 Objections to arsenic, 197 
 Odor, a guide in preparing vats, 296, 
 301 
 
 Oil, dead, 374 
 heavy, 374 
 light, 374 
 
 of cloves, composition of, 236 
 of potatoes, composition of, 236 
 of sesamum, used in dyeing, 357 
 of turpentine, composition of, 236 
 with casein and lime, 223 
 
 Olefiant gas, 111 
 
 Orange, aniline, 382 
 chrome, 191 
 dye, 189 
 
 from acetate of lead, 172 
 from lead, 171 
 
416 
 
 INDEX. 
 
 Orange — 
 
 madder, 389 
 
 victoria, 382 
 Orceine, 353 
 
 composition of, 309 
 Or cine, 353 
 
 Ordway's analysis of iron crystals, 161 
 Ore of antimony, 199 
 
 of molybdenum, 195 
 Ores containing silver, 203 
 
 of arsenic, 196 
 
 of mercury, 202 
 
 of tin, 176, 179 
 Orpiment, 198 
 Osmium, 209 
 Oxalate of copper, 169 
 
 of potash, 118 
 
 of potash and chrome, 110 
 
 of tin, 183 
 Oxalates, 109 
 Oxalic acid, 109 
 Oxide of cadmium, 166 
 
 of copper, 167 
 
 of ianthanium, 210 
 
 of sodium, 124 
 
 of zinc, 165 
 Oxides of antimony, 199 
 
 of arsenic, 196 
 
 of bismuth, 175 
 
 of cerium, 201 
 
 of chromium, 185 
 
 of cobalt, 162 
 
 of gold, 205 
 
 of iridium, 209 
 
 of iron, 151 
 
 of iron, intermediate, 254 
 
 of lead, 170 
 
 of manganese, 149 
 
 of mercury, 202 
 
 of molybdenum, 195 
 
 as mordants, 215 
 
 of nickel, 163 
 
 of osmium, 209 
 
 of palladium, 208 
 
 of platinum, 207 
 
 of rhodium, 209 
 
 of silver, 204 
 
 of tellurium, 196 
 
 of tin, 177 
 
 of titanium, 184 
 
 of tungsten, 194 
 
 of uranium, 200 
 
 of vanadium, 1^4 
 Oxidizing vegetable matters, 168 
 Oxychloride of antimony, 199 
 
 of tin, 177, 180 
 Oxygen, 47 
 
 action in dyeing black, 251, 252 
 
 causes acid, 236 
 
 combinations with iron, 151 
 
 Oxygen — 
 
 false use of the word, 79 
 
 gas, to make, 48 
 Oxygenized muriatic acid, 68 
 Oxymuriatic acid, 68 
 Ozone, 93 
 
 Palladium, 207 
 
 Pao da rain ha, 314 
 
 Paraf and Javal process for black, 397 
 Parkes on frauds in copperas, 155 
 
 on logwood decoctions, 311 
 Paste for calico printing, 345 
 
 for printing aniline black, 397 
 Pastel, 292 
 
 vat, 294 
 Patent for garancine, 341 
 
 for preparing aloes, 363 
 Peachwood, 314 
 Pearlash, 114 
 Peel of walnuts, 259 
 Pelopium, 210 
 
 Penney's method of testing indigo, 274 
 
 test for tin, 180 
 Peonine, 386 
 Pelouze on galls, 242, 243 
 Peracetate of iron, 161 
 Perchloride of gold, 216 
 
 of mercury, 202 
 
 of tin, 180 
 Perhydrate hematoxylin, composition 
 of, 309 
 
 Perkins' aniline violet, 381 
 
 mauveine, 379 
 
 yellow, 387 
 Permanent ink, 204 
 Permanganate, alkaline, 396 
 Permuriate of tin, 180 
 Pernambuco wood, 315 
 Pernod's test for madder, 346 
 Pernod and Picard's madder extracts, 
 397 
 
 Peroxalate of iron, 161 
 Peroxide of gold, 205 
 
 of lead, 171 
 
 of mercury, 202 
 
 of molybdenum, 195 
 
 of nitrogen, 61 
 
 of palladium, 208 
 
 of platinum, 207 
 
 of silver, 204 
 
 of tin, 179 
 
 of uranium, 201 
 Persalts of iron, 158, 162 
 
 of mercury, 202 
 
 of platinum, 207 
 Persian berries, 328 
 Persis, 352 
 
 Persoz on reaction of iron and tannin, 
 252 
 
INDEX. 
 
 4L7 
 
 Persoz — 
 
 peonine or coralline, 385 
 Persulphate of iron, 158 
 Pertartrate of iron, 161 
 Petitclidier's imitation of embroideries, 
 396 
 
 Phenic acid colors, 385 
 
 Phenicienne, 386 
 
 Phenomena from mordants, 146 
 
 Phinacin, 283 
 
 Phoenicians use tin, 176 
 
 Phosphate of potash, 118 
 
 Phosphates attraction for alizarin, 338 
 
 Phosphides, 103 
 
 Phosphine, 382 
 
 Phosphoric acid, 103 
 
 Phosphorus, 103 
 
 Phosphorous acid, 103 
 
 Phosphurets, 103 
 
 Photography, 29 
 
 Picrates, explosive nature of, 386 
 Picric acid, 280, 386 
 
 brown, 387 
 
 greens, 386 
 Pincoffine, 346 
 
 Pink, from saffiower, 330, 331 
 Pipe-clay as a thickening, 147 
 Pittacal, 364 
 
 Plants absorb oxygen, 239 
 Platinum, 206 
 Platinum soldering, 165 
 Plumbago, 107 
 Plumb spirits, 183, 226 
 
 tubs, 310, 313 
 Pohl's method of identifying aniline col- 
 ors, 392 
 Poison by arsenic, 197 
 
 from salts of copper, 169 
 Poisonous effects of lead salts, 173 
 Potash, 113 
 
 alum, 139 
 
 bichromate as a mordant, 228 
 
 bitartrate as a mordant, 228 
 
 chromate of, 187 
 Potatoes, composition of oil, 236 
 Potash, nitrate of, 62 
 
 tellurate of, 196 
 
 specific gravity of, 116 
 
 vats, 293, 300 
 Potassa, effect of bichromate on cate- 
 chu, 255 
 
 isopurpurate of, 386 
 Potassium, 113 
 Potato affected by light, 238 
 Practical application of chemistry, 30 
 Precipitates affected by light, 30 
 
 by alumina salts, 148 
 
 from zinc salts, 165 
 Preisser favors Liebig's theory on in- 
 digo, 279 
 27 
 
 Preisser — 
 
 on barwood, 317 
 
 on Brazil woods, 316 
 Preparation of decoctions, 311 
 
 of lake, 370 
 Preparing aloes, 363 
 
 archil, 352 
 
 the blue vat, 291 
 Preparations of madder, 340 
 Printing aniline greens, 397 
 
 mordants for, 224 
 
 paste, 384 
 
 paste for aniline black, 397 
 without Jacquart loom, 396 
 works, vats in, 291 
 Prismatic colors, 26 
 Processes for selecting indigo, 266, 267 
 Process of dyeing black with sumach, 
 250 
 
 Prohibition of indigo, 260, 261 
 Properties of metals, 112 
 
 of mordants, 232 
 
 of oxygen, 49 
 
 of pure indigo, 268 
 Proposed new vegetable dyes, 355 
 Protochloride of palladium, 208 
 
 of platinum, 207 
 
 of tin, 121, 177 
 Protohydrate hsematoxylin, composi- 
 tion of, 309 
 Protonitrate of iron, 160 
 
 of tin, 178 
 Protosalts of iron, 161 
 Protosulphate of tin, 178 
 Protoxide of cadmium, 166 
 
 of copper, 167 
 
 of lead, 170 
 
 of mercury, 202 
 
 of nitrogen, 60 
 
 of palladium, 208 
 
 of platinum, 207 
 
 of silver, 204 
 
 of tin, 177 
 
 of uranium, 200 
 
 of zinc, 165 
 Prussian blue, 120 
 
 from nitrate of iron, 159 
 Puces, from safflower, 331 
 Pure clay, 141 
 
 indigo, properties of, 268 
 
 water, 51 
 Purification of indigo, 397 
 Purity of soaps, how known, 133 
 Purple, French, 354 
 
 from morindine, 357 
 
 imperial, 381 
 
 madder, 338 
 
 regina, 381 
 Purples from naphthaline, 387 
 Purpurate of ammonia, 371 
 
418 
 
 INDEX. 
 
 Purpurine, 345 
 Purwas used in dyeing, 357 
 Pyrites, iron, to make copperas, 153 
 Pyroligneous acid, 144 
 
 with lead, 172 
 Pyrolignite of alumina, 227 
 
 of iron, 157, 227 
 Pyroxylic spirit, composition of, 236 
 
 with barwood, 319 
 
 Qualities of catechu, 255 
 
 of madder, 334 
 Quality of indigo, to ascertain, 266 
 
 of red liquor, difference in, 145 
 
 of water affects dyeing, 247 
 Quartz, 106 
 Queen-wood, 314 
 Quercitrine, 324 
 Quercitron, 323 
 Quercus infectoria, 242 
 
 nigra, 323 
 Quicksilver, 202 
 
 Radicals, salt, 45 
 
 Rain, nitrate of ammonia in, 62 
 
 Raising, 217 
 
 Reactions of alizarin, 337 
 of alkanet, 352 
 of catechu, 257 
 of cobalt salts, 163 
 of flavine, 326 
 of indigo, 277, 278, 279 
 of kerms, 371 
 of logwood, 309 
 of murexide, 372 
 of quercitron, 323 
 of salts of bismuth, 175 
 
 of cadmium, 166 
 
 of cerium, 202 
 
 of chromium, 193 
 
 of gold, 206 
 
 of lead, 174 
 
 of mercury, 202 
 
 of molybdenum, 195 
 
 of nickel, 164 
 
 of palladium, 208 
 
 of platinum, 207 
 
 of silver, 205 
 
 of tellurium, 196 
 
 of tin, 184 
 
 of uranium, 201 
 
 of vanadium, 194 
 
 of zinc, 165 
 with annotta, 350, 351 
 with archil, 353 
 with barwood solution, 318 
 with camwood, 321 
 with carmine, 366 
 with fustic, 322 
 with fustic (young), 323 
 
 Reactions — 
 
 with garancine, 343 
 
 with salts of copper, 169 
 
 with weld, 327 
 
 with wongshy, 360, 361 
 Reagents which affect salts of manga- 
 nese, 151 
 Realgar, 198 
 Red carthamine, 332 
 
 chromate of potash, 188 
 
 from naphthaline, 387 
 
 lead, 171 
 
 liquor, 144 
 
 difference in quality, 145 
 varieties of, 145 
 
 madder, 338 
 
 oxide of mercury, 202 
 
 precipitate, 202 
 
 prussiate of potash, 122 
 
 spirits, 182, 224 
 
 woods, 314, 320 
 Reds from archil, 353 
 
 from munjeet, 348 
 Regina purple, 381 
 Reimann, dyeing aniline colors, 395 
 Reinsh's method of testing indigo, 272 
 Relation of colors to the fabric, 26 
 Reports on dyeing, etc., 395 
 Repose after a mordant, 229 
 Resin of gamboge, composition of, 236 
 Rhamnus tinctoria, 328 
 Rhodium, 209 
 Rhus cor iaria, 249 
 Rhus cotinus, 323 
 
 Robinson's discovery of a plant in a 
 coal-pit, 238 
 
 Robiquet's method of valuing cochi- 
 neal, 367 
 
 Robiquet and Colin on garancine, 340 
 Rochleder's madder extracts, 397 
 Roman alum preferred as a mordant, 
 228 
 
 vitriol, 168 
 Romans early used indigo, 260 
 Roots of walnut, 259 
 Rosaniline, 379, 380 
 
 greens, 383 
 Roseine, 380 
 Rosin soaps, 398 
 Rothine, 386 
 Roucou, 348 
 
 Roussin's alizarin from naphthaline, 387 
 
 Royal blue, dyeing, 121 
 
 Rubiacic acid, 339 
 
 Rubia memsgista, 333 
 
 Rubian, 344 
 
 Rubia tinctorium, 333 
 
 Rubine, 380 
 
 Ruby, 148 
 
 soluble, 386 
 
INDEX. 
 
 419 
 
 Rules for naming compounds, 37 
 Ruthenium, 210 
 
 Saccharine compounds, 236 
 Saddened colors, 247 
 Safflower, 329 
 Sal-ammoniac, 67 
 
 used by dyers, 183 
 Salt, 124 
 
 cake, 129 
 
 of sorrel, 109 
 
 radicals, 45 
 
 spirit of, 70 
 Salts, action on indigo, 277 
 
 action of metallic, on galls or su- 
 mach, 246 
 
 constitution of, 44 
 
 nature and nomenclature, 39 
 
 of alumina, 148 
 
 of cadmium, 1 66 
 
 of chromium, 186 
 
 of copper, 167 
 
 of strontium, 135 
 
 of tin, 121, 177, 180 
 
 of zinc, 165 
 
 solution of, 57 
 Sampling indigo, 266 
 
 madder, 347 
 Sand, 106 
 Sandal wood, 317 
 Santal, 317 
 Santaline, 317 
 Santa Martha wood, 315 
 Sapan wood, 315 
 Sapphire, 148 
 Saturation, 55 
 Saunders wood, 317 
 Saxon blue, 283 
 Scalding logwood, 310 
 Scarlet from tin, 176 
 Scheele's green, 169, 197 
 Schiel's analysis of morindine, 356 
 Schinus, 359 
 
 Schlumberger's method of obtaining 
 
 pure indigo, 269 
 Scott's nankeen dye, 351 
 Schunck on rubian, 344 
 
 and Pincoffs introduce commercial 
 alizarine, 346 
 Schutzenberger on madder, 344 
 Schtitzenberger's madder extracts, 398 
 Seed-lac, 370 
 
 Selection by dyers of copperas, 155 
 Selenium, 103 
 Senegal indigo, 276 
 Sesamum orientate, 357 
 Sesquioxide of tin, 178 
 Shell-lac, 370 
 Sicilian sumach, 250 
 Silica, 106 
 
 Silicic acid, 106 
 Silicium, 106 
 Silk, 212 
 
 analysis of Neapolitan, 222 
 
 printing with madder, 346 
 
 weight increased by dyeing, 395 
 Silver, 203 
 
 from lead ore, 170 
 
 gray for animal fibres, 397 
 Simple colors, 26 
 Single muriates of tin, 181 
 Sizing warps, cjextrine for, 398 
 Slaked lime, 135 
 Sludge, 288 
 Smalt blue, 163 
 Smyrna galls, 248 
 Soap, 131 
 
 test for water, 53 
 Soaps, rosin, 398 
 Soda, 123 
 
 alum, 139 
 
 aluminate of, 141 
 
 ash, 124, 125 
 
 borate of, 106 
 
 nitrate of, 62 
 
 stanno-arsenite of, 178 
 
 tellurate of, 196 
 
 tungstate of, 194 
 Sodium, 123 
 Soft soap, 132 
 
 water, 52 
 Soldering platinum vessels, 165 
 
 with chloride of zinc, 165 
 Solly on Barbary root, 364 
 Solubility of aniline colors, 388 
 Soluble blues or violets, 389 
 
 ruby, 386 
 Solution of mordants, 215 
 Solutions affected by light, 30 
 Solvent for aniline blacks, 396 
 
 naphtha, 375 
 Solvents for aniline colors, 388 
 Sooranjee, 355 
 
 Sores from chrome and lead, 193 
 Source of water, 52 
 Souring, 76 
 
 Specific gravity of potash, 116 
 Spectrum, 26 
 Spirit of salt, 70 
 Spirits of tin, 181 
 Spurious catechu, 256 
 Stackler on iron mordants, 254 
 Stannic acid, 180 
 
 oxide, 180 
 Stanno-arsenite of soda, 178 
 Stannous salts, 177 
 Starch to adulterate indigo, 273 
 Steaming aniline colors, 390 
 Steam rollers, 147 
 Steeping, 75 
 
420 
 
 INDEX. 
 
 Stenhouse's experiments, 241 
 
 method for obtaining dye from 
 lichens, 353 
 Stein on wongshy, 359 
 Sticking, 90 
 Stick-iac, 370 
 
 potash, 117 
 Stream tin, 176 
 Strong boiling, 22 
 Strontia, 135 
 Strontium, 135 
 
 Study necessary in dyeing, 233 
 Subacetate of alumina, 147 
 Subacetates of lead, 172 
 Subchloride of copper, 167 
 
 of gold, 216 
 Sublimation of indigo, 268 
 Suboxide of copper, 167 
 
 of gold, 205 
 
 of lead, 170 
 
 of mercury, 202 
 
 of phosphorus, 103 
 
 of silver, 204 
 Substances affecting boiling point, 21 
 Substantive colors, 220 
 Sugar, composition of, 235 
 
 of lead, 171 
 
 and gum same in composition, 
 
 235 
 
 Sulphate of alumina, 141 
 of antimony, 199 
 of barytes, 134 
 of bismuth, 175 
 of cadmium, 166 
 of chromium, 186 
 of cobalt, 162 
 of copper, 167 
 of indigo, 283, 285 
 of iron, 152 
 
 of iron as a mordant, 228 
 
 of lead, 173 
 
 of lime, 136 
 
 of manganese, 149 
 
 of mauveine, 381 
 
 of nickel, 164 
 
 of platinum, 207 
 
 of potash, 117 
 
 of silver, 204 
 
 of soda, 129 
 
 of tin, 178 
 
 of zinc, 165 
 Sulphates of lime, 135 
 Sulph-indylic acid, 283 
 Sulphion, 45 
 Sulphite of potash, 118 
 Sulphites, alkaline for printing, 397 
 Sulpho-purpuric acid, 283 
 Sulphur, 93 
 
 Sulphuret of antimony, 199 
 of molybdenum, 195 
 
 Sulphurets of arsenic, 198 
 
 of silver, 203 
 Sulphuretted hydrogen, 101 
 Sulphuric acid, 95 
 
 acid, action on indigo, 283 
 
 acid as a solvent of aniline, 388 
 Sulphurous acid, 94 
 Sumach, 249 
 
 dyes injured by fermentation, 243 
 
 Venetian, 322 
 Sun, acts on Brazil dyes, 317 
 Sweetening, 89 
 
 Swimming, in the blue vat, 289 
 Symbols, 36 
 Sympathetic inks, 162 
 
 Table of condensation of sulphuric acid, 
 97 
 
 of quantity of acids in nitric, &c, 
 65 
 
 of solution of salts, 56, 57 
 of specific gravity of hydrochloric 
 acid, 72 
 
 of strength of sulphuric acid, 99 
 
 of tests for water, 55 
 
 of thermometer scales, 20 
 
 of value of bleaching powder, 84 
 Tannic acid, composition of, 236 
 Tannin, 242 
 
 for cotton printing, 397 
 
 in dye woods, 259 
 
 precipitates aniline colors, 388 
 
 superior for dyeing black, 246 
 Tansy in a coal-pit, 238 
 Tapestry, imitation of, 396 
 Tartar, cream of, as a mordant, 228 
 
 emetic, 200 
 Tartaric acid, composition of, 236 
 Tartrate of antimony and potassa, 200 
 
 of potash and tin, 178 
 Taylor's method of obtaining pure in- 
 digo, 269 
 Technical terms, glossary of, 399 
 Tellurate of potash, 196 
 
 of soda, 196 
 Telluric acid, 196 
 Tellurites, 196 
 Tellurous acid, 196 
 Tellurium, 196 
 Temperature for dyeing, 390 
 
 measures of, 19 
 Terbium, 210 
 Terminalia chebula, 357 
 Terms, glossary of, 399 
 Terra japonic a, 254 
 
 Tessie du Motay and Marechal on alka- 
 line permanganates, 396 
 Test for oxalic acid, 109 
 
 for quantity of tin, 180 
 
 glass, 86 
 
INDEX. 
 
 421 
 
 Testing copperas, 156 
 logwood, 312 
 madder, 336 
 mordant, 145 
 soap, 133 
 soda-ash, 126 
 
 the value of lead salts, 174 
 Tests for alum, 139 
 for annotta, 351 
 for bichromate of potash, 1 93 
 for bleaching powder, 81 
 for impurities in nitric acid, 64 
 for indigo, 266, 267, 268, 269, 
 272 
 
 for litharge, 170 
 
 for madder, 346 
 
 for silver, 204 
 • for water, 53 
 
 for wool, cotton, flax, &c, 213 
 Textile fabrics, 211 
 
 fabrics, generalities on, 213 
 
 fabrics rendered fire-proof, 194 
 Thenard and Hoard's experiments, 229 
 Theories of composition of white in- 
 digo, 278 
 Theory of aniline colors, 377 
 
 of bleaching, 77 
 
 of mordants, 228 
 
 of the blue vat, 288 
 Thermometers, 20 
 
 Thorn on elective affinity of coloring 
 
 matters and bases, 324 
 Thomson on changes in indigo, 264 
 Tin, 175 
 
 acted on by nitrate of copper, 168 
 chloride, best mordant from Bra- 
 zil wood, 317 
 chloride of, as a mordant, 228 
 effect of salts on catechu, 255 
 mordant, 215 
 
 and iron for royal blue, 227 
 Tinkal, 130 
 Tinstone, 179 
 Titanium, 184 
 
 Tobacco kept moist with chloride of 
 
 zinc, 165 
 Toluidine greens, 383 
 Tribasic acetate of lead, 172 
 Trinitrophenic acid, 386 
 Triphenylic rosaniline, 379 
 Tungstate of soda, 194 
 Tungstenum, 194 
 Tungstic acid, 194 
 Turkey red dyeing, 357 
 Turmeric, 328 
 
 Turpentine, composition of oil, 236 
 TwaddelPs hydrometer, 64, 65 
 
 Uncropped madder, 334 
 Union of elements, 35 
 
 Universal exposition, dyeing in, 395 
 Uranium, 200 
 
 Ure on gases from indigo, 263 
 Uric acid, dye from, 372 
 Urine colored by madder, 338 
 Useful products of madder, 339 
 Use of potash to dyers, 114 
 
 of symbols, 36 
 Uses of tin in dyeing, 176 
 
 Valerianic acid, 279, 282 
 
 Valonia nuts, 258 
 
 Value of aniline colors, 391 
 
 of cochineal, 367 
 
 of indigo, 271 
 
 of indigo, to know, 266, 267 
 
 of iron liquor, 157 
 
 of lead salts, 174 
 
 of logwood, 312 
 
 of varieties of copperas, 155 
 
 of wongshy as a color, 361 
 Values of madder extracts, 397 
 Vanadic acid, 193 
 Vanadium, 193 
 Varieties of madder, 334 
 
 of red liquor, 145 
 
 of sulphate of iron, 155 
 Vat, blue, how made, 288 
 Vats, 288, 291, 293, 294, 297, 300, 302, 
 305 
 
 management of, 302 
 Vegetable alkali, 113 
 dyes, new, 355 
 
 fibres, mordants for coal-tar colors, 
 395 
 
 fibres, no affinity for coal-tar co- 
 lors, 390 
 
 matters used in dyeing, 234 1 
 
 substances, elements of, 234 
 Vegetables, gallic acid not found largely 
 in, 243 
 
 oxygen in, 47 
 Venetian sumach, 322 
 Verdigris, 169 
 Verona sumach, 250 
 Vert lumiere, 383 
 Victoria orange, 382 
 Vinegar, composition of, 236 
 
 to make white lead, 171 
 sugar of lead, 171 
 Violaniline, 379 
 Violets, aniline, 381 
 
 soluble, 389 
 Viol & Duflot, feather bleaching, 396 
 Virey on carajuru, 358 
 Vitality affects the color, 240 
 Vitriol, blue, 168 
 
 green, 152 
 
 white, 165 
 Vogei's dye, 382 
 
422 
 
 INDEX. 
 
 \ 
 
 Walnut for dyeing, 259 
 
 Warrington's method of ascertaining 
 
 quantity of tannin, 259 
 Water, 50 
 
 action on indigo, 277 
 
 as a solvent, 55 
 
 oxygen in, 47 
 
 quality of affects dyeing, 247 
 required to dissolve green vitriol, 
 
 153 
 tests for, 53 
 Weight of silk increased by dyeing, 
 395 
 
 Weissgerber's experiments with oil, 
 
 358 
 Weld, 326 
 
 White copperas, 165 
 indigo, 264, 277 
 lead, 171 
 
 oxide of arsenic, 197 
 pattern on blue ground, 282 
 vitriol, 165 
 
 Wild cochineal, 366 
 
 Williams, discovery of fast green, &c, 
 327 
 
 Woad plant, 260 
 
 vat, 297 
 
 and pastel, 292 
 Wold, 326 
 Wolfram, 194 
 Wongshy, 359 
 
 colors from, 362 
 
 dyeing with, 261 
 
 reactions with, 360, 361 
 
 Stein on, 359 
 
 value as a color, 361 
 Woods, 314 
 
 extracts of, 326 
 
 red, 314, 320 
 
 Wood vinegar with lead, 172 
 yellow, 321 
 
 Woody fibre, composition of, 235 
 
 Wool, 212 
 
 aniline black on, 396 
 dyeing with purpurine, 346 
 
 Woollens, mordant for, 228 
 
 Wools, tests for, 213 
 
 Xanthin, 337 
 Xanthine, 344 
 Xantho-rhamnine, 328 
 
 Yellow chromate of potash, 187 
 chrome, 189 
 
 from acetate of lead, 172 
 from lead, 171 
 from naphthaline, 387 
 madder, 339 
 Manchester, 387 
 Martius', 387 
 naphthylamine, 387 
 Perkins', 
 
 prussiate of potash, 119 
 
 spirits, 183, 226 
 
 wood, 321 
 Yellows, aniline, 382 
 Young fustic, 322 
 
 Zinaline, 382 
 Zinc, 164 
 
 oxide of, 165 
 
 chloride of, 165 
 
 detected in copperas, 156 
 
 nitrate of, 165 
 
 salts of, 165 
 
 salts, precipitates for, 1 65 
 salts, reactions of, 165 
 sulphate of, 165 
 
CATALOGUE 
 
 OF 
 
 PRACTICAL AND SCIENTIFIC BOOKS, 
 
 PUBLISHED BY 
 
 HENRY CAREY BAIRD, 
 
 INDUSTRIAL PUBLISHER, 
 IsTo- 406 WJ^JL.JSTTjrr STREET, 
 PHILADELPHIA. 
 
 ' Any of the Books comprised In this Catalogue will be sent by mail, 
 free of postage, at the publication price. 
 
 My New and Enlarged Catalogue, 95 pages Svo., with full descriptions 
 of Books, will be sent, free of postage, to any one who will favor m 
 with his address. 
 
 ARMENGAUD, AMOUROUX, AND JOHNSON—THE PRACTICAL 
 DRAUGHTSMAN'S BOOK OF INDUSTRIAL DESIGN, AND 
 MACHINIST'S AND ENGINEER'S DRAWING COMPANION: 
 
 Forming a complete course of Mechanical Engineering and 
 Architectural Drawing. From the French of M. Armengaud 
 the elder, Prof, of Design in the Conservatoire of Arts and 
 Industry, Paris, and MM. Armengaud the younger and Amou- 
 roux, Civil Engineers. Rewritten and arranged, with addi- 
 tional matter and plates, selections from and examples of the 
 most useful and generally employed mechanism of the day. 
 By William Johnson, Assoc. Inst. C. E., Editor of "The 
 Practical Mechanic's Journal." Illustrated by 50 folio steel 
 plates and 50 wood-cuts. A new edition, 4to. . $10 00 
 
 A RLOT. — A COMPLETE GUIDE FOR COACH PAINTERS. 
 
 Translated from the French of M. Arlot, Coach Painter late 
 Master Painter for eleven years with M. Ehrler, Coach Manufac- 
 turer, Paris. With important American additions . . $1 25 
 
 A RROWSMITH.— PAPER-HANGER'S COMPANION : 
 
 A Treatise in which the Practical Operations of the Trade are 
 Systematically laid down: with Copious Directions Prepara- 
 tory to Papering; Preventives against the Effect of Damp on 
 Walls; the Various Cements and Pastes adapted to the Seve- 
 ral Purposes of the Trade ; Observations and Directions for 
 the Panelling and Ornamenting of Rooms, &c. By James 
 Arrowsmith. 12mo., cloth $1 25 
 
2 
 
 HENRY CAREY BAIRD'S CATALOGUE. 
 
 ■D:\IRD.— THE AMERICAN COTTON SPINNER, AND MANA- 
 ^ GER'S AND CARDER'S GUIDE * 
 
 A Practical Treatise on Cotton Spinning; giving the Dimen- 
 sions and Speed of Machinery, Draught and Twist Calcula- 
 tions, etc. ; with notices of recent Improvements : together 
 with Rules and Examples for making changes in the sizes and 
 numbers of Roving and Yarn. Compiled from the papers of 
 the late Robert H. Baird. 12mo. . . . $1 50 
 
 "DAKER. — LONG-SPAN RAILWAY BRIDGES : 
 
 Comprising Investigations of the Comparative Theoretical and 
 Practical Advantages of the various Adopted or Proposed Type 
 Systems of Construction; with numerous Formulae and Ta- 
 bles. By B. Baker. 12mo $2 00 
 
 •DAKEWELL.— A MANUAL OF ELECTRICITY— PRACTICAL AND 
 - 0 THEORETICAL : 
 
 By F. C. Bakewell, Inventor of the Copying Telegraph. Se* 
 cond Edition. Revised and enlarged. Illustrated by nume- 
 rous engravings. 12mo. Cloth .... 
 
 •DEANS — A TREATISE ON RAILROAD CURVES AND THE L0- 
 D CATION OF RAILROADS : 
 
 By E. W. Beans, C. E. 12mo. ... $2 00 
 
 "DLENKARN. — PRACTICAL SPECIFICATIONS OF WORKS EXE- 
 D CUTED IN ARCHITECTURE, CIVIL AND MECHANICAL 
 
 ENGINEERING, AND IN ROAD MAKING AND SEWER. 
 
 ING: 
 
 To which are added a series of practically useful Agreements 
 and Reports. By John Blenkarn. Illustrated by fifteen 
 large folding plates. 8vo $9 00 
 
 "DLINN. — A PRACTICAL WORKSHOP COMPANION FOR TIN, 
 ■° SHEET-IRON, AND COPPER-PLATE WORKERS : 
 
 Containing Rules for Describing various kinds of Patterns 
 used by Tin, Sheet-iron, and Copper-plate Workers ; Practical 
 Geometry ; Mensuration of Surfaces and Solids ; Tables of the 
 Weight of Metals, Lead Pipe, etc. ; Tables of Areas and Cir- 
 cumferences of Circles ; Japans, Varnishes, Lackers, Cements, 
 Compositions, etc. etc. By Leroy J. Blinn, Master Me- 
 chanic. With over One Hundred Illustrations. 12nm $2 50 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 1 
 
 BOOTH. -MARBLE WORKER'S MANUAL: 
 
 Containing Practical Information respecting Marbles in gene- 
 ral, their Cutting, Working, and Polishing ; Veneering of 
 Marble ; Mosaics ; Composition and Use of Artificial Marble, 
 Stuccos, Cements, Receipts, Secrets, etc. etc. Translated 
 from the French by M. L. Booth. With an Appendix con- 
 cerning American Marbles. 12mo., cloth . . $1 50 
 
 BOOTH AND MORFIT. — THE ENCYCLOPEDIA OF CHEMISTRY, 
 n PRACTICAL AND THEORETICAL : 
 
 Embracing its application to the Arts, Metallurgy, Mineralogy, 
 Geology, Medicine, and Pharmacy. By James C. Booth, 
 Melter and Refiner in the United States Mint, Professor of 
 Applied Chemistry in the Franklin Institute, etc., assisted by 
 Campbell Morfit, author of "Chemical Manipulations," etc. 
 Seventh edition. Complete in one volume, royal 8vo., 978 
 pages, with numerous wood-cuts and other illustrations. $5 00 
 
 DOWDITCH.— ANALYSIS, TECHNICAL VALUATION, PURIEI- 
 D CATION, AND USE OF COAL GAS : 
 
 By Rev. W. R. Bowditch. Illustrated with wood engrav- 
 ings. 8vo. $6 50 
 
 "DOX. — PRACTICAL HYDRAULICS: 
 
 A Series of Rules and Tables for the use of Engineers, etc. 
 By Thomas Box. 12mo. $2 50 
 
 "DU CKMASTER. — THE ELEMENTS OF MECHANICAL PHYSICS : 
 
 By J. C. Buckmaster, late Student in the Government School 
 of Mines ; Certified Teacher of Science by the Department of 
 Science and Art ; Examiner in Chemistry and Physics in the 
 Royal College of Preceptors ; and late Lecturer in Chemistry 
 and Physics of the Royal Polytechnic Institute. Illustrated 
 with numerous engravings. In one vol. 12mo. . $1 50 
 
 pULLOCK. — THE AMERICAN COTTAGE BUILDER : 
 
 A Series of Designs, Plans, and Specifications, from $200 to 
 to $20,000 for Homes for the People ; together with Warm- 
 ing, Ventilation, Drainage, Painting, and Landscape Garden- 
 ing. By John Bullock, Architect, Civil Engineer, Mechani- 
 cian, and Editor of " The Rudiments of Architecture and 
 Building," etc. Illustrated by 75 engravings. In one vol. 
 8vo $3 50 
 
4 
 
 HENRY CAREY BAXRD'S CATALOGUE!. 
 
 BULLOCK. — THE RUDIMENTS OF ARCHITECTURE AND 
 D BUILDING : 
 
 For the use of Architects, Builders, Draughtsmen, Machin- 
 ists, Engineers, and Mechanics. Edited by John Bullock, 
 author of "The American Cottage Builder." Illustrated by 
 250 engravings. In one volume 8vo. . . . $3 50 
 
 •BURGH.— PRACTICAL ILLUSTRATIONS OF LAND AND MA- 
 n RINE ENGINES : 
 
 Showing in detail the Modern Improvements of High and Low 
 Pressure, Surface Condensation, and Super-heating, together 
 with Land and Marine Boilers. By N. P. Burgh, Engineer. 
 Illustrated by twenty plates, double elephant folio, with text. 
 
 $21 00 
 
 BURGH.— PRACTICAL RULES FOR THE PROPORTIONS OF 
 D MODERN ENGINES AND BOILERS FOR LAND AND MA- 
 RINE PURPOSES. 
 
 By N. P. Burgh, Engineer. 12mo. . . . $2 00 
 "DURGH. — THE SLIDE-VALVE PRACTICALLY CONSIDERED : 
 
 By N. P. Burgh, author of " A Treatise on Sugar Machinery," 
 "Practical Illustrations of Land and Marine Engines," " A 
 Pocket-Book of Practical Rules for Designing Land and Ma- 
 rine Engines, Boilers," etc. etc. etc. Completely illustrated. 
 
 12mo. * . . $2 00 
 
 "BYRN. — THE COMPLETE PRACTICAL BREWER : 
 
 Or, Plain, Accurate, and Thorough Instructions in the Art of 
 Brewing Beer, Ale, Porter, including the Process of making 
 Bavarian Beer, all the Small Beers, such as Root-beer, Ginger- 
 pop, Sarsaparilla-beer, Mead, Spruce beer, etc. etc. Adapted 
 to the use of Public Brewers and Private Families. By M. La 
 Fayette Byrn, M. D. With illustrations. 12mo. $1 25 
 
 YRJST.— THE COMPLETE PRACTICAL DISTILLER : 
 
 Comprising the most perfect and exact Theoretical and Prac- 
 tical Description of the Art of Distillation and Rectification ; 
 including all of the most recent improvements in distilling 
 apparatus ; instructions for preparing spirits from the nume- 
 rous vegetables, fruits, etc. ; directions for the distillation and 
 preparation of all kinds of brandies and other spirits, spiritu- 
 ous and other compounds, etc. etc. ; all of which is so simpli- 
 fied that it is adapted not only to the use of extensive distil- 
 lers, but for every farmer, or others who may wish to engage 
 in the art of distilling By M. La Fayette Byrn, M. D. 
 With numerous engravings. In one volume, 12mo. $1 50 
 
 B 
 
HENRY CAREY B AIRE'S CATALOGUE 
 
 DYRNE. — POCKET BOOK FOR RAILROAD AND CIVIL ENG1- 
 - 0 NEERS: 
 
 Containing New, Exact, and Concise Methods for Laying out 
 Railroad Curves, Switches, Frog Angles and Crossings; the 
 Staking out of work; Levelling; the Calculation of Cut- 
 tings ; Embankments ; Earth-work, etc. By Oliver Byrne. 
 Illustrated, 18mo,, full bound . . . . $1 75 
 
 DYRNE. — THE HANDBOOK FOR THE ARTISAN, MECHANIC, 
 AND ENGINEER : 
 
 By Oliver Byrne. Illustrated by 185 Wood Engravings. 8vo. 
 
 $5 00 
 
 "DYRNE.— THE ESSENTIAL ELEMENTS OF PRACTICAL ME- 
 n CHANICS: 
 
 For Engineering Students, based on the Principle of Work. 
 By Oliver Byrne. Illustrated by Numerous Wood Engrav- 
 ings, 12mo. ........ $3 63 
 
 DYRNE. — THE PRACTICAL METAL-WORKER'S ASSISTANT: 
 Comprising Metallurgic Chemistry ; the Arts of Working all 
 Metals and Alloys ; Forging of Iron and Steel ; Hardening and 
 Tempering ; Melting and Mixing ; Casting and Founding ; 
 Works in Sheet Metal; the Processes Dependent on the 
 Ductility of the Metals ; Soldering ; and the most Improved 
 Processes and Tools employed by Metal- Workers. With the 
 Application of the Art of Electro-Metallurgy to Manufactu- 
 ring Processes ; collected from Original Sources, and from the 
 Works of Holtzapffel, Bergeron, Leupold, Plumier, Napier, and 
 others. By Oliver Byrne. A New, Revised, and improved 
 Edition, with Additions by John Scoffern, M. B , William Clay, 
 Wm. Fairbairn, F. R. S., and James Napier. With Five Hun- 
 dred and Ninety-two Engravings ; Illustrating every Branch 
 of the Subject. In one volume, 8vo. 652 pages . $7 00 
 
 DYRNE.— THE PRACTICAL MODEL CALCULATOR: 
 
 For the Engineer, Mechanic, Manufacturer of Engine Work, 
 Naval Architect, Miner, and Millwright. By Oliver Byrne. 
 1 volume, 8vo., nearly 600 pages . . . . $4 50 
 
 JgEMRO SE. — MANUAL OF WOOD CARVINGr : With Practical Il- 
 lustrations for Learners of the Art, and Original and Selected de- 
 signs. By William Bemrose, Jr. With an Introduction by 
 Llewellyn Jewitt, F. S. A., etc. With 128 Illustrations. 4to. ? 
 cloth $3 00 
 
S HENRY CAREY BAIRD'S CATALOGUE. 
 
 "DAIRD. — PROTECTION OF HOME LABOR AND HOME PRO- 
 ■° SUCTIONS NECESSARY TO THE PROSPERITY OF THE 
 AMERICAN FARMER : 
 
 By Henry Carey Baird. 8vo., paper . * 10 
 
 B 
 
 B 
 
 AIRD. — THE RIGHTS OF AMERICAN PRODUCERS, AND THE 
 WRONGS OF BRITISH FREE TRADE REVENUE REFORM. 
 
 By Henry Carey Baird. (1870) .... 5 
 
 AIRD.— SOME OF THE FALLACIES OF BRITISH-FREE-TRADE 
 REVENUE-REFORM. 
 
 Two Letters to Prof. A. L. Perry, of Williams College, Mass. By 
 Henry Carey Baird. (1871.) Paper .... 5 
 
 B 
 
 ]g AIRD . — STANDARD WAGES COMPUTING TABLES : 
 
 An Improvement in all former Methods of Computation, so ar- 
 ranged that wages for days, hours, or fractions of hours, at a spe- 
 cified rate per day or hour, may be ascertained at a glance. By 
 T. Spangler Baird. Oblong folio $5 00 
 
 AUERMAN. — TREATISE ON THE METALLURGY OF IRON. 
 
 Illustrated. 12mo $2 50 
 
 DICKNELL'.S VILLAGE BUILDER. 
 
 *° 55 large plates. 4to $10 00 
 
 BISHOP.— A HISTORY OF AMERICAN MANUFACTURES : 
 
 From 1608 to 1866 ; exhibiting the Origin and Growth of the Prin- 
 cipal Mechanic Arts and Manufactures, from the Earliest Colonial 
 Period to the Present Time ; By J. Leander Bishop, M. D., Ed- 
 ward Young, and Edwin T. Freedley. Three vols. 8vo., 
 
 $10 00 
 
 OX.— A PRACTICAL TREATISE ON HEAT AS APPLIED TO 
 THE USEFUL ARTS : 
 
 For the use of Engineers, Architects, etc. By Thomas Box, au- 
 thor of " Practical Hydraulics." Illustrated by 14 plates, con- 
 taining 114 figures. 12mo $4 25 
 
 B 
 
 QABINET MAKER'S ALBUM OF FURNITURE : 
 
 Comprising a Collection of Designs for the Newest and Most 
 Elegant Styles of Furniture. Illustrated by Forty-eight Large 
 and Beautifully Engraved Plates. In one volume, oblong 
 
 $5 00 
 
 QHAPMAN.— A TREATISE ON ROPE-MAKING : 
 
 As practised in private and public Rope-yards, with a Description 
 of the Manufacture, Rules, Tables of Weights, etc., adapted to the 
 Trade ; Shipping, Mining, Railways, Builders, etc. By Robert 
 Chapman. 24mo, . . . . ■. - . ~ $1 50 
 
 \ 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 7 
 
 pRAIK.— THE PRACTICAL AMERICAN MILLWRIGHT AND 
 U MILLER. 
 
 Comprising the Elementary Principles of Mechanics, Me- 
 chanism, and Motive Power, Hydraulics and Hydraulic 
 Motors, Mill-dams, Saw Mills, Grist Mills, the Oat Meal Mill, 
 the Barley Mill, Wool Carding, and Cloth Fulling and Dress- 
 ing, Wind Mills, Steam Power, &c. By David Craik, Mill' 
 wright. Illustrated by numerous wood engravings, and five 
 folding plates. 1 vol. 8vo. „ . . . $5 00 
 
 HAMPIN. — A PRACTICAL TREATISE ON MECHANICAL EN- 
 U GINEERING: 
 
 Comprising Metallurgy, Moulding, Casting, Forging, Tools, 
 Workshop Machinery, Mechanical Manipulation, Manufacture 
 of Steam-engines, etc. etc. With an Appendix on the Ann- 
 lysis of Iron and Iron Ores. By Fbancis Campin, C. E. To 
 which are added, Observations on the Construction of Steam 
 Boilers, and Remarks upon Furnaces used for Smoke Preven- 
 tion; with a Chapter on Explosions. By R. Armstrong, C. E. s 
 and John Bourne. Rules for Calculating the Change Wheels 
 for Screws on a Turning Lathe, and for a Wheel-cutting 
 Machine. By J. La Nicca. Management of Steel, including 
 Forging, Hardening, Tempering, Annealing, Shrinking, anc( 
 Expansion. And the Case-hardening of Iron. By G. Ede. 
 8vo. Illustrated with 29 plates and 100 wood engravings. 
 
 $6 00 
 
 rt AMP IN. —THE PRACTICE OF HAND-TURNING IN WOOD, 
 U IVORY, SHELL, ETC. i 
 
 With Instructions for Turning such works in Metal as maybe 
 required in the Practice of Turning Wood, Ivory, etc. Also 
 an Appendix on Ornamental Turning. By Francis Campin , 
 with Numerous Illustrations, 12mo., cloth . . $3 00 
 
 pAPRON DE DOLE, — DITSSAUCE. — BLUES AND CARMINES OF 
 U INDIGOc 
 
 A Practical Treatise on the Fabrication of every Commercial 
 Product derived from Indigo. By Felicien Capron de Dole 
 Translated, with important additions, by Professor H. Dc$» 
 sauce. 12mo. 
 
HENRY CAREY BAIRDS CATALOGUE. 
 
 IAREY. — THE WORKS OF HENRY C> CAREY : 
 
 CONTRACTION OR EXPANSION t REPUDIATION OR RE- 
 SUMPTION? Letters to Hon. Hugh McCulloch. 8yo. 38 
 FINANCIAL CRISES, their Causes and Effects. 8vo. paper 
 
 25 
 
 HARMONY OF INTERESTS; Agricultural, Manufacturing, 
 
 and Commercial. 8vo. r paper $1 00 
 
 Do. do. cloth . . . $1 50 
 
 LETTERS TO THE PRESIDENT OF THE UNITED STATES. 
 Paper $1 00 
 
 MANUAL OF SOCIAL SCIENCE. Condensed from Carey's 
 " Principles of Social Science/* By Kate McKean. 1 vol. 
 12mo . . $2 25 
 
 MISCELLANEOUS WORKS: comprising "Harmony of Inter- 
 ests," " Money," 1 "Letters to the President," "French and 
 American Tariffs," "Financial Crises," "The Way to Outdo 
 England without Fighting Her," " Resources of the Union," 
 "The Public Debt," "Contraction or Expansion," "Review 
 of the Decade 1857 — '67," "Reconstruction," etc. etc. 1 vol. 
 
 8vo., cloth . $4 50 
 
 MONEY: A LECTURE before the N. Y. Geographical and Sta- 
 tistical Society. 8vo., paper 25 
 
 PAST, PRESENT, AND FUTURE. 8vo. . . . $2 50 
 
 PRINCIPLES OF SOCIAL SCIENCE. 3 volumes 8vo.; cloth 
 
 $10 00 
 
 REVIEW OF THE DECADE 1857— '67. 8vo., paper 50 
 RECONSTRUCTION : INDUSTRIAL, FINANCIAL, AND PO- 
 LITICAL. Letters to the Hon. Henry Wilson, U. S. S. 8vo 
 paper ....... . 50 
 
 THE PUBLIC DEBT, LOCAL AND NATIONAL. How to 
 provide for its discharge while lessening the burden of Taxa- 
 tion. Letter to David A. Wells, Esq., U. S. Revenue Commis- 
 sion. 8vo., paper ....... 25 
 
 THE RESOURCES OF THE UNION. A Lecture read, Dec. 
 1865, before the American Geographical and Statistical So- 
 ciety, N. Y., and before the American Association for the- Ad- 
 vancement of Social Science, Boston ... 50 
 
 THE SLAVE TRADE, DOMESTIC AND FOREIGN; Why it 
 Exists, and How it may be Extinguished. 12mo., cloth $1 50 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 9 
 
 LETTERS ON INTERNATIONAL COPYRIGHT. (1867.) 
 
 Paper • 50 
 
 KEVIEW OF THE FARMERS' QUESTION. (1870.) Paper 25 
 
 RESUMPTION! HOW IT MAY PROFITABLY BE BROUGHT 
 AROUT. (1869.) 8vo., paper .... 50 
 
 REVIEW OF THE REPORT OF HON. D. A. WELLS, Special 
 Commissioner of the Revenue. (1869.) 8vo., paper 50 
 
 SHALL WE HAVE PEACE? Peace Financial and Peace Poli- 
 tical. Letters to the President Elect. (1868.) 8vo., paper 50 
 
 THE FINANCE MINISTER AND THE CURRENCY, AND 
 THE PUBLIC DEBT. (1868.) 8vo., paper . . 50 
 
 THE WAY TO OUTDO ENGLAND WITHOUT FIGHTING 
 HER. Letters to Hon. Schuyler Colfax. (1865.) 8vo., paper 
 
 $1 00 
 
 WEALTH! OF WHAT DOES IT CONSIST ? (1870.) Paper 25 
 
 HAMUS.— A TREATISE ON THE TEETH OF WHEELS : 
 
 Demonstrating the best forms which can be given to them for the 
 purposes of Machinery, such as Mill-work and Clock-work. Trans- 
 lated from the French of M. Camus. By John I. Hawkins. 
 Illustrated by 40 plates. 8vo $3 00 
 
 pIOXE. — MINING LEGISLATION. 
 
 A paper read before the Am. Social Science Association. By 
 Eckley B. Coxe. Paper 20 
 
 p 0LBTJRN . — THE GAS-WORKS OF LONDON: 
 
 Comprising a sketch of the Gas-works of the city, Process of 
 Manufacture, Quantity Produced, Cost, Profit, etc. By Zerah 
 Colburn. 8vo., cloth 75 
 
 H0LBTJRN. — THE LOCOMOTIVE ENGINE : 
 
 Including a Description of its Structure, Rules for Estimat- 
 ing its Capabilities, and Practical Observations on its Construc- 
 tion and Management. By Zerah Colburn. Illustrated. A 
 new edition. 12mo. $1 25 
 
 riOLBURN AND MAW. — THE WATER-WORKS OF LONDON: 
 Together with a Series of Articles on various other Water- 
 works. By Zerah Colburn and W. Maw. Reprinted front 
 " Engineering." In one volume, 8vo. . . $4 00 
 
 nAGTJERREOTYPIST AND PHOTOGRAPHER'S COMPANION: 
 
 JJ 12mo. 7 cloth $1 25 
 
10 
 
 HENRY CAREY BAIRD'S CATALOGUE. 
 
 "HIRCKS.— PERPETUAL MOTION : 
 
 Or Search for Self-Motive Power during the 17th, 18th, and 
 19th centuries. Illustrated from various authentic sources in 
 Papers, Essays, Letters, Paragraphs, and numerous Patent 
 Specifications, with an Introductory Essay by Henry Dircks, 
 C. E. Illustrated by numerous engravings of machines. 
 12mo., cloth $3 50 
 
 TJIXON. — THE PRACTICAL MILLWRIGHT'S AND ENGINEER'S 
 ■ U GUIDE : 
 
 Or Tables for Finding the Diameter and Power of Cogwheels ; 
 Diameter, Weight, and Power of Shafts ; Diameter and Strength 
 of Bolts, etc. etc. By Thomas Dixon. 12mo., cloth. $1 50 
 
 JJUNCAN. — PRACTICAL SURVEYOR'S GUIDE: 
 
 Containing the necessary information to make any person, of 
 common capacity, a finished land surveyor without the aid of 
 a teacher. By Andrew Duncan. Illustrated. 12mo., cloth. 
 
 $1 25 
 
 "nUSSAUCE.— A NEW AND COMPLETE TREATISE ON THE 
 13 ARTS OF TANNING, CURRYING, AND LEATHER DRESS- 
 ING : 
 
 Comprising all the Discoveries and Improvements made in 
 France, Great Britain, and the United States. Edited from 
 Notes and Documents of Messrs. Sallerou, Grouvelle, Duval, 
 Dessables, Labarraque, Payen, Rene\ De Fontenelle, Mala- 
 peyre, etc. etc. By Prof. H. Dussauce, Chemist. Illustrated 
 
 by 212 wood engravings. 8vo $10 00 
 
 TjUSSAUCE. — A GENERAL TREATISE ON THE MANUFACTURE 
 OF SOAP, THEORETICAL AND PRACTICAL : 
 Comprising the Chemistry of the Art, a Description of all the Raw 
 Materials and their Uses. Directions for the Establishment of a 
 Soap Factory, with the necessary Apparatus, Instructions in the 
 Manufacture of every variety of Soap, the Assay and Determination 
 of the Value of Alkalies, Fatty Substances, Soaps, etc. etc. By 
 Professor H. Dussauce. With an Appendix, containing Ex- 
 tracts from the Reports of the International Jury on Soaps, as 
 exhibited in the Paris Universal Exposition, 1867, numerous 
 Tables, etc. etc. Illustrated by engravings. In one volume 8vo. 
 
 of over 800 pages . . $10 00 
 
 ,USSAUCE.— PRACTICAL TREATISE ON THE FABRICATION 
 OF MATCHES, GUN COTTON, AND FULMINATING POW- 
 DERS. 
 
 By Professor H. Dussauce. 12mo. . . . $3 00 
 
 D 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 11 
 
 TJUSSAUCE. — A PRACTICAL GUIDE FOR THE PERFUMER : 
 
 Being a New Treatise on Perfumery the most favorable to the 
 Beauty without being injurious to the Health, comprising a 
 Description of the substances used in Perfumery, the Form- 
 ulae of more than one thousand Preparations, such as Cosme- 
 tics, Perfumed Oils, Tooth Powders, Waters, Extracts, Tinc- 
 tures, Infusions, Vinaigres, Essential Oils, Pastels, Creams, 
 Soaps, and many new Hygienic Products not hitherto described. 
 Edited from Notes and Documents of Messrs. Debay, Lunel, 
 etc. With additions by Professor H. Dussauce, Chemist. 12mo. 
 
 $3 00 
 
 TYUSSAUCE. — A GENERAL TREATISE ON THE MANUFACTURE 
 - L ' OF VINEGAR, THEORETICAL AND PRACTICAL. 
 
 Comprising the various methods, by the slow and the quick pro- 
 cesses, with Alcohol, Wine, Grain, Cider, and Molasses, as weft 
 as the Fabrication of Wood Vinegar, etc. By Prof. H. Dussauce. 
 12mo. $5 00 
 
 TYUPLAIS. — A COMPLETE TREATISE ON THE DISTILLATION 
 U AND MANUFACTURE OF ALCOHOLIC LIQUORS : 
 
 From the French of M. Duplais. Translated and Edited by M. 
 McKennie, M D. Illustrated by numerous large plates and wood 
 engravings of the best apparatus calculated for producing the 
 finest products. In one vol. royal 8vo. $10 00 
 
 This is a treatise of the highest scientific merit and of the 
 greatest practical value, surpassing in these respects, as well as 
 in the variety of its contents, any similar volume in the English 
 language. 
 
 [YE GRAFF.— THE GEOMETRICAL STAIR-BUILDERS' GUIDE: 
 
 Being a Plain Practical System of Hand-Railing, embracing all 
 its necessary Details, and Geometrically Illustrated by 22 Steel 
 Engravings ; together with the use of the most approved princi- 
 ples of Practical Geometry. By Simon De Graff, Architect. 
 
 4to. . $5 00 
 
 TjYER AND COLOR-MAKER'S COMPANION : 
 
 Containing upwards of two hundred Receipts for making Co- 
 lors, on the most approved principles, for all the various styles 
 and fabrics now in existence ; with the Scouring Process, and 
 plain Directions for Preparing, Washing-off, and Finishing the 
 Oroods. In one vol. 12mo $1 25 
 
12 HENRY OaRBY BAIRD'S CATALOGUE. 
 
 1? AST ON. — A PKACTICAL TREATISE ON STREET OR HORSE- 
 POWER RAILWAYS : 
 
 Their Location, Construction, and Management ; with General 
 Plans and Rules for their Organization and Operation ; toge- 
 ther with Examinations as to their Comparative Advantages 
 over the Omnibus System, and Inquiries as to their Value for 
 Investment; including Copies of Municipal Ordinances relat- 
 ing thereto. By Alexander Easton, C. E. Illustrated by 23 
 plates, 8vo., cloth . $2 00 
 
 pSRSYTH. — BOOK OF DESIGNS FOR HEAB-STONES, MURAL, 
 C AND OTHER MONUMENTS : 
 
 Containing 78 Elaborate and Exquisite Designs. By Forsyth. 
 
 4to., cloth . . / . $5 00 
 
 This volume, for the beauty and variety of its designs, has 
 never been surpassed by any publication of the kind, and should 
 be in the hands of every marble-worker who does fine monumental 
 work. 
 
 pAIRBAIRN.— THE PRINCIPLES OF MECHANISM AND MA- 
 X CHINERY OF TRANSMISSION : 
 
 Comprising the Principles of Mechanism, Wheels, and Pulleys, 
 Strength and Proportions of Shafts, Couplings of Shafts, and 
 Engaging and Disengaging Gear. By William Fairbairn, 
 Esq., C. E., LL. D., F. R. S., F. G. S., Corresponding Member 
 of the National Institute of France, and of the Royal Academy 
 of Turin ; Chevalier of the Legion of Honor, etc. etc. Beau- 
 tifully illustrated by over 150 wood-cuts. In one volume 12mo. 
 
 $2 50 
 
 pAIRBAIRN.— PRIME-MOVERS : 
 
 Comprising the Accumulation of Water-power ; the Construc- 
 tion of Water-wheels and Turbines; the Properties of Steam; 
 the Varieties of Steam-engines and Boilers and Wind-mills. 
 By William Fairbairn, C. E., LL. D., F. R. S., F. G. S. Au- 
 thor of " Principles of Mechanism and the Machinery of Trans- 
 mission. " With Numerous Illustrations. In one volume. (In 
 press.) 
 
 piLBART. — A PRACTICAL TREATISE ON BANKING: 
 
 ^ By James William Gilbart. To which is added: The Na- 
 tional Bank Act as now in force. 8vo. . .$4 5® 
 
 HESNER. — A PRACTICAL TREATISE ON COAL, PETROLEUM, 
 ^ AND OTHER DISTILLED OILS. 
 
 By Abraham Gesner, M. D., F. G. S. Second edition, revised 
 and enlarged. By George Weltden Gesner, Consulting 
 Chemist and Engineer. Illustrated. 8vo. • . $3 50 
 
HENRY CAREY BAIRNS CATALOGUE, 
 
 nOTHIC ALBUM FOR CABINET MAKERS: 
 
 Comprising a Collection of Designs for Gothic Furniture. Ii< 
 lustrated by twenty-three large and beautifully engraved 
 plates. Oblong $3 00 
 
 H RANT. — BEET-ROOT SUGAR AND CULTIVATION OF THE 
 ^ BEET : 
 
 By E. B. Grant. 12mo. . . ■ . . . $1 25 
 
 H REGORY. — MATHEMATICS FOR PRACTICAL MEN : 
 
 Adapted to the Pursuits of Surveyors, Architects, Mechanics, 
 and Civil Engineers. By Olinthus Gregory. 8vo., plates, 
 cloth $3 00 
 
 HRISWOLD. — RAILROAD ENGINEER'S POCKET COMPANION. 
 
 Comprising Rules for Calculating Deflection Distances and 
 Angles, Tangential Distances and Angles, and all Necessary 
 Tables for Engineers ; also the art of Levelling from Prelimi- 
 nary Survey to the Construction of Railroads, intended Ex- 
 pressly for the Young Engineer, together with Numerous Valu- 
 able Rules and Examples. By W. Griswold. 12mo., tucks. 
 
 $1 75 
 
 H UETTIER. — METALLIC ALLOYS : 
 
 Being a Practical Guide to their Chemical and Physical Pro- 
 perties, their Preparation, Composition, and Uses. Translated 
 from the French of A. Guettier, Engineer and Director of 
 Founderies, author of ' ' La Fouderie en France," etc. etc. By 
 A. A. Fesquet, Chemist and Engineer, In one volume, 12mo. 
 
 $3 00 
 
 TTATS AND FELTING: 
 
 A Practical Treatise on their Manufacture. By a Practical 
 
 Hatter. Illustrated by Drawings of Machinery, &c, 8vo. 
 
 $1 2k 
 
 XT AY. — THE INTERIOR DECORATOR: 
 
 The Laws of Harmonious Coloring adapted to Interior Decora- 
 tions : with a Practical Treatise on House-Painting. By D. 
 R. Hat, House-Painter and Decorator. Illustrated by a Dia- 
 gram of the Primary, Secondary, and Tertiary Colors. 12mo. 
 
 $2 25 
 
 TTUGHES.— AMERICAN MILLER AND MILLWRIGHT'S AS- 
 11 SI ST ANT : 
 
 By Wm. Carter Hughes. A new edition. In one volume, 
 12mo. . . . . . ... $1 50 
 
14 HENRY CAREY BAIRD'S CATALOGUE. 
 
 JJUNT. — THE PRACTICE OF PHOTOGRAPHY. 
 
 By Robert Hunt, Vice-President of the Photographic Society, 
 London. With numerous illustrations. 12mo., cloth . 75 
 
 RST.— A HAND-BOOK FOR ARCHITECTURAL SURVEYORS r 
 
 Comprising Formulse useful in Designing Builders' work, Table 
 of Weights, of the materials used in Building, Memoranda 
 connected with Builders' work, Mensuration, the Practice of 
 Builders' Measurement, Contracts of Labor, Valuation of Pro- 
 perty, Summary of the Practice in Dilapidation, etc. etc. By 
 J. F. Hurst, C. E. 2d edition, pocket-book form, full bound 
 
 $2 50 
 
 !RVIS. — RAILWAY PROPERTY: 
 
 A Treatise on the Construction and Management of Railways ; 
 designed to aiford useful knowledge, in the popular style, to the 
 holders of this class of property as well as Railway Mana- 
 gers, Officers, and Agents. By John B. Jervis, late Chief 
 Engineer of the Hudson River Railroad, Croton Aqueduct^ &c. 
 One vol. 12mo., cloth . . $2 00 
 
 'OHNSON. — A REPORT TO THE NAVY DEPARTMENT OF THE 
 UNITED STATES ON AMERICAN COALS : 
 
 Applicable to Steam Navigation and to other purposes. By 
 Walter R. Johnson. With numerous illustrations. 607 pp. 
 8vo.,, . ... $10 00 
 
 0HNST0N.— INSTRUCTIONS FOR THE ANALYSIS OF SOILS, 
 LIMESTONES, AND MANURES 
 
 By J. W. F. Johnston. 12mo. . 35 
 
 gTSENE. — A HAND-BOOK OF PRACTICAL GAUGING, 
 
 For the Use of Beginners, to which is added a Chapter on Dis- 
 tillation, describing the process in operation at the Custom 
 House for ascertaining the strength of wines. By James B. 
 Keene, of H. M. Customs. 8vo, . . $1 25 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 gENTISH.— A TREATISE ON A BOX OF INSTRUMENTS, ' 
 
 And the Slide Rule ; with the Theory of Trigonometry and Lo- y 
 garithms, including Practical Geometry, Surveying, Measur- 
 ing of Timber, Cask and Malt Gauging, Heights, and Distances. 
 By Thomas Kentish. In one volume. 12mo. . . $1 25 
 
 OBELL.—ERNL— MINERALOGY SIMPLIFIED : 
 
 A short method of Determining and Classifying Minerals, by 
 means of simple Chemical Experiments in the Wet Way. 
 Translated from the last German Edition of F. Von Kobell, 
 with an Introduction to Blowpipe Analysis and other addi- 
 tions. By Henri Erni, M. D., Chief Chemist, Department of 
 Agriculture, author of "Coal Oil and Petroleum." In one 
 volume. 12mo. . . $2 50 
 
 ANDRIN. — A TREATISE ON STEEL: 
 
 Comprising its Theory, Metallurgy, Properties, Practical Work- 
 ing, and Use. By M. H. C. Landrin, Jr., Civil Engineer. 
 Translated from the French, with Notes, by A. A. Fesquet, 
 Chemist and Engineer. With an Appendix on the Bessemer 
 and the Martin Processes for Manufacturing Steel, from the 
 Report of Abram S. Hewitt, United States Commissioner to 
 the Universal Exposition, Paris, 1867. 12mo. . . $3 00 
 
 ARKIN. — THE PRACTICAL BRASS AND IRON FOUNDER'S 
 1 GUIDE. 
 
 A Concise Treatise on Brass Founding, Moulding, the Metals 
 and their Alloys, etc. ; to which are added Recent Improve- 
 ments in the Manufacture of Iron, Steel by the Bessemer Pro- 
 cess, etc. etc. By James Larkin, late Conductor of the Brass 
 Foundry Department in Reany, Neafie & Co.'s Penn Works, 
 Philadelphia. Fifth edition, revised, with extensive Addi- 
 tions. Ia one volume. 12mo. . . . . $2 25 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 T EAVITT. — FACTS ABOUT PEAT AS AN ARTICLE OF FUEL? 
 
 With Remarks upon its Origin and Composition, the Localities 
 m which it is found, the Methods of Preparation and Manu 
 facture, and the various Uses to which it is applicable ; toge 
 ther with many other matters of Practical and Scientific Inte- 
 rest. To which is added a chapter on the Utilization of Coal 
 Dust with Peat for the Production of an Excellent Fuel at 
 Moderate Cost, especially adapted for Steam Service. By H. 
 T. Leavitt. Third edition. 12mo. . . . $1 75 
 
 T ER0UX= — A PRACTICAL TREATISE ON THE MANUFAC- 
 TURS OF WORSTEDS AND CARDED YARNS: 
 Translated from the French of Charles Leroux, Mechanical 
 Engineer, and Superintendent of a Spinning Mill. By Dr, H. 
 Paine, and A. A. Fesquet. Illustrated by 12 large plates, In 
 one volume 8vo. . $5 00 
 
 TESLIE (MISS) . — COMPLETE COOKERY : 
 
 Directions for Cookery in its Various Branches. By Miss 
 Leslie. 60th edition. Thoroughly revised, with the addi- 
 tion of New Receipts. In 1 vol. 12mo., cloth . . $1 50 
 
 TESLIE (MISS). LADIES' HOUSE BOOK: 
 
 a Manual of Domestic Economy. 20th revised edition. 12mo., 
 cloth . . . $1 25 
 
 TESLIE (MISS) .—TWO HUNDRED RECEIPTS IK FRENCH 
 Jj COOKERY. 
 
 12mo 50 
 
 T IEBER. — ASSAYER'S GUIDE : 
 
 Or, Practical Directions to Assayers, Miners, and Smelters, for 
 the Tests and Assays, by Heat and by Wet Processes, for the 
 Ores of all the principal Metals, of Gold and Silver Coins and 
 Alloys, and of Coal, etc. By Oscar M. Lieber. 12mo., cloth 
 
 $1 25 
 
 T OVE. — THE ART OF DYEING, CLEANING, SCOURING, AND 
 U FINISHING ; 
 
 On the most approved English and French methods ; being 
 Practical Instructions in Dyeing Silks, Woollens,, and Cottons, 
 Feathers, Chips, Straw, etc.; Scouring and Cleaning Bed and 
 Window Curtains, Carpets, Rugs, etc.; French and English 
 Cleaning, etc. By Thomas Love. Second American Edition, to 
 which are added General Instructions for the Use of Aniline 
 Colors.. 8vo.. r . . . „ * • „ , 5 00 
 
HENRY CAREY BAIRD'S CATALOGUE. 17 
 
 M 
 
 M 
 
 TWTAIN AND BROWN. — QUESTIONS ON SUBJECTS CONNECTED 
 1V1 WITH THE MARINE STEAM-ENGINE : 
 
 And Examination Papers ; with Hints for their Solution. By 
 Thomas J. Main, Professor of Mathematics, Royal Naval College, 
 and Thomas Brown, Chief Engineer, R.N. 12mo., cloth $1 50 
 
 AIN AND BROWN. — THE INDICATOR AND DYNAMOMETER 
 
 With their Practical Applications to the Steam-Engine. By 
 Thomas J. Main, M. A. F. R., Ass't Prof. Royal Naval College, 
 Portsmouth, and Thomas Brown, Assoc. Inst. C. E., Chief En- 
 gineer, R. N., attached to the R. N. College. Illustrated. From 
 the Fourth London Edition. 8vo. ... . $1 50 
 
 AIN AND BROWN — THE MARINE STEAM-ENGINE. 
 
 By Thomas J. Main, F. R. Ass't S. Mathematical Professor at 
 Royal Naval College, and Thomas Brown, Assoc. Inst. C. E. 
 Chief Engineer, R. N. Attached to the Royal Naval College. 
 Authors of " Questions Connected with the Marine Steam-En- 
 gine," and the '* Indicator and Dynamometer." With numerous 
 Illustrations. In one volume 8vo. . . . . . $5 00 
 
 ARIIN.— SCREW-CUTTING TABLES, FOR THE USE OF ME- 
 CHANICAL ENGINEERS : 
 
 Showing the Proper Arrangement of Wheels for Cutting the 
 Threads of Screws of any required Pitch ; with a Table for 
 Making the Universal Gas-Pipe Thread and Taps. By W. A. 
 
 Martin, Engineer. 8vo 50 
 
 ILES — A PLAIN TREATISE ON HORSE-SHOEING. 
 With Illustrations. By William Miles, author of "The Horse's 
 Foot" 
 
 TUTOLES WORTH. — POCKET-BOOK OF USEFUL FORMULAE AND 
 1YJ - MEMORANDA FOR CIVIL AND MECHANICAL EN3INEERS. 
 
 By Guilford L. Molesworth, Member of the Institution of 
 Civil Engineers, Chief Resident Engineer of the Ceylon Railway. 
 Second American from the Tenth London Edition. In one 
 volume, full bound in pocket-book form . . . . $2 0(1 
 
 OORE.— THE INVENTOR'S GUIDE: 
 
 Patent Office and Patent Laws : or, a Guide to Inventors, and a 
 Book of Reference for Judges, Lawyers, Magistrates, and others. 
 
 By J G. Moore. 12mo., cloth $1 25 
 
 APIER. — A MANUAL OF ELECTRO-METALLURGY : 
 Including the Application of the Art to Manufacturing Processes. 
 By James Napier. Fourth American, from the Fourth London 
 edition, revised and enlarged. Illustrated by engravings. In 
 one volume, 8vo $2 00 
 
 M 
 
 M 
 
 M' 
 
 N 
 
18 HENRY CAREY BAIRD'S CATALOGUE. 
 
 "VTAPIER. — A SYSTEM OF CHEMISTRY APPLIED TO DYE IN ft : 
 
 By James Napier, F. C. S. A New and Thoroughly Revised 
 Edition, completely brought up to the present state of the 
 Science, including the Chemistry of Coal Tar Colors. By A. A. 
 Fesquet, 'Chemist and Engineer. With an Appendix on Dyeing 
 and Calico Printing, as shown at the Paris Universal Exposition 
 of 1867, from the Reports of the International Jury, etc. Illus- 
 trated. In one volume 8vo., 400 pages . . . . $5 00 
 
 TVTEWBERY. — GLEANINGS FROM ORNAMENTAL ART OF 
 
 ^ EVERY STYLE; 
 
 Drawn from Examples in the British, South Kensington, Indian, 
 Crystal Palace, and other Museums, the Exhibitions of 1851 and 
 1862, and the best English and Foreign works. In a series of one 
 hundred exquisitely drawn Plates, containing many hundred ex- 
 amples. By Robert Newbery. 4to $15 00 
 
 jy^ICHOLSON. — A MANUAL OF THE ART OF BOOK-BINDING : 
 
 Containing full instructions in the different Branches of Forward- 
 ing, Gilding, and Finishing. Also, the Art of Marbling Book- 
 edges and Paper. By James B. Nicholson. Illustrated. 12mo. 
 cloth .... ..... $2 2i 
 
 ■VTORRIS.— A HAND-BOOK FOR LOCOMOTIVE ENGINEERS AND 
 1N MACHINISTS: 
 
 Comprising the Proportions and Calculations for Constructing 
 Locomotives ; Manner of Setting Valves ; Tables of Squares, 
 Cubes, Areas, etc. etc. By Septimus Norris, Civil and Me- 
 chanical Engineer. New edition. Illustrated, 12mo., cloth 
 
 $2 00 
 
 MYSTROM. — ON TECHNOLOGICAL EDUCATION AND THE 
 r CONSTRUCTION OF SHIPS AND SCREW PROPELLERS: 
 
 For Naval and Marine Engineers. By John W. Nystrom, late 
 Acting Chief Engineer U. S. N. Second edition, revised with 
 additional matter. Illustrated by seven engravings. 12mo. 
 
 $2 50 
 
 NEILL. — A DICTIONARY OF DYEING AND CALICO PRINT- 
 ING: 
 
 Containing a brief account of all the Substances and Processes in 
 use in the Art of Dyeing and Printing Textile Fabrics : with Prac- 
 tical Receipts and Scientific Information. By Charles O'Neill, 
 Analytical Chemist ; Fellow of the Chemical Society of London ; 
 Member of the Literary and Philosophical Society of Manchester ; 
 Author of " Chemistry of Calico Printing and Dyeing." To which 
 is added An Essay on Coal Tar Colors and their Application to 
 
 0 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 19 
 
 0 
 
 Dyeing and Calico Printing. By A. A. Fesquet, Chemist and 
 Engineer. With an Appendix on Dyeing and Calico Printing, as 
 shown at the Exposition of 1867, from the Reports of the Interna, 
 tional Jury, etc. In one volume 8vo., 491 pages . . $6 00 
 S BORN.— THE METALLURGY OF IRON AND STEEL: 
 
 Theoretical and Practical : In all its Branches ; With Special Re- 
 ference to American Materials and Processes. By H. S. Osborn, 
 LL. D., Professor of Mining and Metallurgy in Lafayette College, 
 Easton, Pa. Illustrated by 230 Engravings on Wood, and 6 
 
 Folding Plates. 8vo., 972 pages $10 00 
 
 QSBORN. — AMERICAN MINES AND MINING : 
 v Theoretically and Practically Considered. By Prof. H. S. Os- 
 born, Illustrated by numerous engravings. 8vo. {hi preparation.) 
 pAINTER, GILDER, AND VARNISHER'S COMPANION : 
 
 Containing Rules and Regulations in everything relating to the 
 Arts of Painting, Gilding, Varnishing, and Glass Staining, with 
 numerous useful and valuable Receipts; Tests for the Detection 
 of Adulterations in Oils and Colors, and a statement of the Dis- 
 eases and Accidents to which Painters, Gilders, and Varnishers 
 are particularly liable, with the simplest methods of Prevention 
 and Remedy. With Directions for Graining, Marbling, Sign Writ- 
 ing, and Gilding on Glass. To which are added Complete Instruc- 
 tions for Coach Painting and Varnishing. 12mo., cloth, $1 50 
 
 pALLETT. — THE MILLER'S, MILLWRIGHT'S, AND ENGI- 
 L NEER'S GUIDE. 
 
 By Henry Pallett. Illustrated. In one vol. 12mo. . $3 00 
 pERKINS.— GAS AND VENTILATION. 
 
 Practical Treatise on Gas and Ventilation. With Special Relation 
 to Illuminating, Heating, and Cooking by Gas. Including Scien- 
 tific Helps to Engineer-students and others. With illustrated 
 Diagrams. By E. E. Perkins. 12mo., cloth . . . $1 25 
 
 HEREIN S AND ST OWE. — A NEW GUIDE TO THE SHEET-IRON 
 
 L AND BOILER PLATE ROLLER : 
 
 Containing a Series of Tables showing the Weight of Slabs and 
 Piles to Produce Boiler Plates, and of the Weight of Piles and the 
 Sizes of Bars to Produce Sheet-iron ; the Thickness of the Bar 
 Gauge in Decimals ; the Weight per foot, and the Thickness on 
 the Bar or Wire Gauge of the fractional parts of an inch ; the 
 Weight per sheet, and the Thickness on the Wire Gauge of Sheet- 
 iron of various dimensions to weigh 112 lbs. per bundle ; and the 
 conversion of Short Weight into Long Weight, and Long Weight 
 into Short. Estimated and collected by G» II. Perkins and J. G' 
 Stowe . , , $2 50 
 
20 
 
 HENRY CAREY BAIRD'S CATALOGUE. 
 
 pHILLIPS AND DARLINGTON.— RECORDS OF MINING AND 
 £ METALLURGY : 
 
 Or, Facts and Memoranda for the use of the Mine Agent and 
 Smelter. By J. Arthur Phillips, Mining Engineer, Graduate of 
 the Imperial School of Mines, France, etc., and John Darlington. 
 Illustrated by numerous engravings. In one vol. 12mo. . $2 00 
 pRADAL, MALEPEYRE, AND DUS SAUCE. — A COMPLETE 
 TREATISE ON PERFUMERY : 
 
 Containing notices of the Raw Material used in the Ait, and the 
 Best Formulae. According to the most approved Methods followed 
 in France, England, and the United States. By M. P. Pradal, 
 Perfumer-Chemist, and M. F. Malepeyre. Translated from the 
 French, with extensive additions, by Prof. H. Dussauce. 8vo. $10 
 
 pROTEAUX.— PRACTICAL GUIDE FOR THE MANUFACTURE 
 X OF PAPER AND BOARDS. 
 
 By A. Proteaux, Civil Engineer, and Graduate of the School of 
 Arts and Manufactures, Director of Thiers's Paper Mill, 7 Puy-de- 
 Dome. With additions, by L. S. Le Normand. Translated from 
 the French, with Notes, by Horatio Paine, A. B., M. D. To 
 which is added a Chapter on the Manufacture of Paper from Wood 
 in the United States, by Henry T. Brown, of the "American 
 Artisan." Illustrated by six plates, containing Drawings of Raw 
 Materials, Machinery, Plans of Paper-Mills, etc. etc. 8vo. $5 00 
 TD EGNAULT. — ELEMENTS OF CHEMISTRY. 
 
 By M. Y. Regnault. Translated from the French by T. For- 
 rest Benton, M. Ik , and edited, with notes, by James C. Booth, 
 Melter and Refiner U. S. Mint, and Wm. L. Faber, Metallurgist 
 and Mining Engineer. Illustrated by nearly 700 wood engravings » 
 Comprising nearly 1500 pages. In two vols. 8vo., cloth $10 00 
 
 TDEID. — A PRACTICAL TREATISE ON THE MANUFACTURE OF 
 11 PORTLAND CEMENT: 
 
 By Henry Reid, C. E. To which is added a Translation of M. 
 A. Lipowitz's Work, describing a new method adopted in Germany 
 of Manufacturing that Cement. By W. F. Rem. Illustrated by 
 plates and wood engravings. 8vo. . . . . . $7 00 
 
 •DIFFAULT, VERGNAUD, AND TOUSSAINT. — A PRACTICAL 
 11 TREATISE ON THE MANUFACTURE OF COLORS FOR 
 PAINTING: 
 
 Containing the best Formulae and the Processes the Newest and 
 in most General Use. By MM. Riffault, Vergnaub, and Tous- 
 saint. Revised and Edited by M. F. Malepeyre and Dr. Emil 
 Winckler. Illustrated by Engravings* In one voL Svo. {In 
 preparation^ 
 
HENRY CAREY BATRD'S CATALOGUE. 
 
 21 
 
 DIFEAULT, VERGrNAUD, AND TOUSSAINT.— A PRACTICAL 
 TREATISE ON THE MANUFACTURE OF VARNISHES : 
 
 By MM. Riffault, Vergnaud, and Toussaint. Revised and 
 Edited by M. F. Malepeyre and Dr. Emil Winckler. Illus- 
 trated. In one vol. 8vo. (hi preparation.) 
 
 OHUNK. — A PRACTICAL TREATISE ON RAILWAY CURVES 
 ° AND LOCATION, FOR YOUNG ENGINEERS. 
 
 By Wm. F. Shunk, Civil Engineer. 12mo., tucks . . $2 00 
 
 gMEATON.— BUILDER'S POCKET COMPANION: 
 
 Containing the Elements of Building, Surveying, and Architec. 
 ture ; with Practical Rules and Instructions connected with the sub- 
 ject. By A. C. Smeaton, Civil Engineer, etc. In one volume, 
 12mo. . . $1 50 
 
 HMITH.— THE DYER'S INSTRUCTOR: 
 
 Comprising Practical Instructions in the Art of Dyeing Silk, Cot- 
 ton, Wool, and Worsted, and Woollen Goods: containing nearly 
 800 Receipts. To which is added a Treatise on the Art of Pad- 
 ding j and the Printing of Silk Warps, Skeins, and Handkerchiefs, 
 and the various Mordants and Colors for the different styles of 
 such work. By David Smith, Pattern Dyer, 12mo., cloth 
 
 $3 0& 
 
 OMITH.— THE PRACTICAL DYER'S GUIDE: 
 
 Comprising Practical Instructions in the Dyeing of Shot Cobourgs, 
 Silk Striped Orleans, Colored Orleans from Black Warps, ditto 
 from White Warps, Colored Cobourgs from White Warps, Merinos, 
 Yarns, Woollen Cloths, etc. Containing nearly 300 Receipts, to 
 most of which a Dyed Pattern is annexed. Also, a Treatise on 
 the Art of Padding. By David Smith. In one vol. 8vo. $25 00 
 
 OHAW. — CIVIL ARCHITECTURE : 
 
 Being a Complete Theoretical and Practical System of Building, 
 containing the Fundamental Principles of the Art. By Edward 
 Shaw, Architect. To which is added a Treatise on Gothic Archi- 
 tecture, &c. By Thomas W. Silloway and George M. Hard- 
 ing , Architects. The whole illustrated by 102 quarto plates finely 
 engraved on copper. Eleventh Edition. 4to. Cloth. $10 00 
 
 OLOAN. — AMERICAN HOUSES : 
 
 A variety of Original Designs for Rural Buildings. Illustrated by 
 26 colored Engravings, with Descriptive References. By Samuel 
 Sloan, Architect, author of the " Model Architect," etc. etc. 8vo. 
 
 $2 50 
 
 OCHINZ.— RESEARCHES ON THE ACTION OF THE BLAST. 
 D FURNACE. 
 
 By Chas. Schinz. Seven plates. 12mo. . . $4 25 
 
 \ 
 
22 
 
 HENRY CAREY BAIRD'S CATALOGUE. 
 
 OMITH.— PARKS AND PLEASURE GROUNDS : 
 
 Or, Practical Notes on Country Residences, Villas, Public Parks, 
 and Gardens. By Charles H. J. Smith, Landscape Gardener 
 and Garden Architect, etc. etc. 12mo. . , . . $2 25 
 
 OTOKES.— CABINET-MAKER'S AND UPHOLSTERER'S COMPA- 
 ° NION: 
 
 Comprising the Rudiments and Principles of Cabinet-making and 
 Upholstery, with Familiar Instructions, Illustrated by Examples 
 for attaining a Proficiency in the Art of Drawing, as applicable 
 to Cabinet-work ; The Processes of Veneering, Inlaying, and 
 Buhl-work ; the Art of Dyeing and Staining Wood, Bone, Tortoise 
 Shell, etc. Directions for Lackering, Japanning, and Varnishing; 
 to make Prench Polish ; to prepare the Best Glues, Cements, and 
 Compositions, and a number of Receipts, particularly for workmen 
 generally. By J. Stokes. In one vol. 12mo. With illustrations 
 
 $1 25 
 
 STRENGTH AND OTHER PROPERTIES OF METALS. 
 
 Reports of Experiments on the Strength and other Properties of 
 Metals for Cannon. With a Description of the Machines for Test- 
 ing Metals, and of the Classification of Cannon in service. By 
 Officers of the Ordnance Department U. S. Army. By authority 
 of the Secretary of War. Illustrated by 25 large steel plates. In 
 1 vol. quarto . . $10 00 
 
 SULLIVAN. — PROTECTION TO NATIVE INDUSTRY. 
 
 ^ By Sir Edward Sullivan, Baronet. (1870.) 8vo. . $1 5C 
 
 ryiABLES SHOWING THE WEIGHT OF ROUND, SQUARE, AND 
 1 FLAT BAR IRON, STEEL, ETC. 
 
 By Measurement. Cloth 63 
 
 rpAYLOR. — STATISTICS OF COAL: 
 
 ^" Including Mineral Bituminous Substances employed in Arts and 
 Manufactures j with their Geographical, Geological, and Commer- 
 cial Distribution and amount of Production and Consumption on 
 the American Continent. With Incidental Statistics of the Iron 
 Manufacture. By R. C. Taylor. Second edition, revised by S. 
 S. Haldeman. Illustrated by five Maps and many wood engrav- 
 ings. 8vo., cloth . . $6 00 
 
 riPEMPLETON. — THE PRACTICAL EXAMINATOR ON STEAM 
 A AND THE STEAM-ENGINE : 
 
 With Instructive References relative thereto, for the Use of Engi- 
 neers, Students, and others. By War. Templeton, Engineer 12mo- 
 
 SI 25 
 
HENRY CAREY BAIRD'S CATALOGUE. 
 
 23 
 
 IHOMAS. — THE MODERN PRACTICE OF PHOTOGRAPHY. 
 
 By R. W. Thomas, F. C. S. 8vo., cloth .... 75 
 «*PHOMSON. — FREIGHT CHARGES CALCULATOR. 
 
 By Andrew Thomson, Freight Agent . . . . $1 25 
 TURNING : SPECIMENS OF FANCY TURNING EXECUTED ON 
 * THE HAND OR FOOT LATHE : 
 
 With Geometric, Oval, and Eccentric Chucks, and Elliptical Cut- 
 ting Frame. By an Amateur. Illustrated by 30 exquisite Pho- 
 tographs. 4to $3 00 
 
 ^TURNER'S (THE) COMPANION: 
 
 Containing Instructions in Concentric, Elliptic, and Eccentric 
 Turning; also various Plates of Chucks, Tools, and Instru- 
 ments ; and Directions for using the Eccentric Cutter, Drill, 
 Vertical Cutter, and Circular Rest ; with Patterns and Instruc- 
 tions for working them. A new edition in 1 vol. 12mo. $1 50 
 
 TTRBIN — BRULL.— A PRACTICAL GUIDE FOR PUDDLING 
 U IRON AND STEEL. 
 
 By Ed. Urbtn, Engineer of Arts and Manufactures. A Prize 
 Essay read before the Association of Engineers, Graduate of the 
 School of Mines, of Liege, Belgium, at the Meeting of 1865-6. 
 To which is added a Comparison of the Resisting Properties 
 of Iron and Steel. By A. Brull. Translated from the French 
 by A. A. Fesquet, Chemist and Engineer. In one volume, 8vo. 
 
 $1 00 
 
 TTOGDES. — THE ARCHITECT'S AND BUILDER'S POCKET COM- 
 V PANION AND PRICE BOOK. 
 
 By F. W. Vogdes, Architect. Illustrated. Full bound in pocket* 
 
 book form . . $2 00 
 
 In book form, 18mo., muslin . . , . . 1 50 
 
 WARN.— THE SHEET METAL WORKER'S INSTRUCTOR, FOR 
 VV ZINC, SHEET-IRON, COPPER AND TIN PLATE WORK- 
 ERS, &c. 
 
 By Reuben Henry Warn, Practical Tin Plate Worker. Illus- 
 trated by 32 plates and 37 wood engravings. 8vo. . . $3 CO 
 
 yn-ATSON.— A MANUAL OF THE HAND-LATHE. 
 
 " By Egbert P. Watson, Late of the " Scientific American," Au- 
 thor of "Modern Practice of American Machinists and Engi- 
 neers," In one volume, 12mo. . . . . . $1 50 
 
24 
 
 HENRY CAREY BAIRD'S CATALOGUE. 
 
 WATSON.— THE MODERN PRACTICE OF AMERICAN MA. 
 VY CHINISTS AND ENGINEERS : 
 
 Including the Construction, Application, and Use of Drills, Lathe 
 Tools, Cutters for Boring Cylinders, and Hollow Work Generally, 
 with the most Economical Speed of the same, the Results verified 
 by Actual Practice at the Lathe, the Vice, and on the Floor. 
 Together with Workshop management, Economy of Manufacture, 
 the Steam-Engine, Boilers, Gears, Belting, etc. etc. By Egbert 
 P. Watson, late of the " Scientific American. " Illustrated by 
 eighty-six engravings. 12mo. $2 50 
 
 WATSON.— THE THEORY AND PRACTICE OF THE ART OF 
 
 VV WEAVING BY HAND AND POWER: 
 
 With Calculations and Tables for the use of those connected with 
 the Trade. By John Watson, Manufacturer and Practical Machine 
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 And other processes for Confectionery, &c. In which are ex- 
 plained, in an easy and familiar manner, the various Methods 
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 From the Transactions of the Society of Engineers, 1867. By 
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 OHLER.— A HAND-BOOK OF MINERAL ANALYSIS. 
 
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 L. B. CAT. NO. 1137 
 
 
 
N 163 
 
 1 
 
 GETTY CENTER LIBRARY 
 
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 j 3125 00140 5899